Microbio 420 Lecture 2

Passive immunity

means that human body is not producing its own antibody against microbe or toxin. The antibody present in blood stream were produced elsewhere. •Specific antibody introduced in to the host •Host immune system does not produce specific antibodies against the microbe -Ab transfer from mother -Injection of antibody

Active immunity

means that human body is producing its own antibody against microbe or toxin and has the antibody in blood stream. •Microbial antigens appear in the host, •Host immune system produces specific antibodies against the microbe -infection -vaccination

T/F If 19 students in a class of 53 receive the measles vaccine, the remaining students in the class will be protected from measles by herd immunity.

False

T/F If the virus is present as a provirus in the host cell, it remains latent and never produces new virus.

False

T/F There is a proven scientific association between autism and vaccination, particularly the MMR vaccine.

False

T/F. All of the wrestlers who contracted HSV-1 or impetigo in this case did so at the January 24-25 competition.

False

T/F. Influenza viruses that have undergone antigenic drift are more problematic than those that have undergone antigenic shift because antigenic drift leads to annual influenza epidemics.

False

T/F. Mycobacterium tuberculosis does not have a peptidoglycan cell wall.

False

Directly observed therapy short-course (DOTS)

method to ensure that patient complies with their tuberculosis treatment: healthcare worker watches while patient takes medication

T/F 3. Some of the patients at the dialysis facility were already infected with HCV prior to the outbreak described in the case study.

True A small proportion of patients at the facility were already infected with hepatitis C before the outbreak occurred and investigators surmised that the new infections most likely came from these patients rather than the staff.

T/F. The lipids of foamy macrophages are thought to facilitate M. tuberculosis survival in the host cell.

True

Croup

acute obstruction of the larynx resulting from respiratory viral infection

If you look inside the core or capsid of HIV, you will find three enzymes: reverse transcriptase, integrase, and ______.

protease The protease functions late in HIV replication

Multidrug-resistant tuberculosis (MDR-TB)

strains of Mycobacterium tuberculosis resistant to the first line anti-TB drugs, isoniazid and rifampicin

Please label the figure to show your understanding of HIV replication. Two labels are unused.

(going counter clockwise, starting on top left) -Viral genome and reverse transcript (RT) enter cell -DNA copy synthesized by RT -RNA degraded, second DNA strand synthesized -DNA copy is incorporated by integrase into host cell genome, forming provirus -with host cell activation, viral DNA is transcribed, giving mRNAs and genome RNA -viral RNA translated, giving viral enzymes and structural proteins -viral membrane proteins are transported to host cell membrane -first viral assembly and budding occurs

What percentage of the compounds originally screened show effectiveness against both multiplying and dormant bacteria?

0.16%

What percentage of the total number of people with CA-MRSA in this case (primary and secondary infections) improved with only drainage of their lesions?

36.3%

Immunoassays can be used

All of the answer choices to detect very small quantities of antigen. to detect very small quantities of antibody. to diagnose viral infections. Immunoassays are extremely sensitive tests that permit rapid and accurate measurement of antibody and antigen, including those of viral origin.

The causative agents of pertussis and tuberculosis differ in that

B. Pertussis produces exotoxins that damage the host, while M. tuberculosis does not Bordetella pertussis makes three exotoxins that damage host cells, while Mycobacterium tuberculosis does not make any exotoxins.

Which parts of the respiratory system have no normal microbiota? Check all that apply.

Bronchioles Trachea Alveoli Lungs

Which of the following medications created the largest zone of inhibition?

Chloramphenicol The largest zone of inhibition was measured at 27 mm around the disc containing chloramphenicol.

Why are human bite wounds potentially so dangerous?

Crushed tissue and the presence of facultative anaerobes depletes O2 in the wound, fostering growth of anaerobic microbes introduced into the site by the bite.

What signs/symptoms does a person develop when they first inhale Mycobacterium tuberculosis?

Generally none—they are aymptomatic

Immunologic disorders

Immunologic disorders are various dysfunctions of the immune system.

Infections of lower respiratory system

Pertussis (whooping cough) Tuberculosis Bacterial pneumonia Influenza

The USA principal vaccines

Preventing bacterial diseases DTaP (replaced older DTP or DTwP) Purified diphtheria & tetanus toxoids Fragments of Bordetella pertussis cell wall MCV-4 or MPSV-4 Purified polysaccharide from N. meningitidis PCV-7 (PCV-13) (PCV-23) Polysaccharides of 7 (13) (23) S. pneumoniae serotypes conjugated to diphtheria toxoid, CRM197 Hib- Polysaccharides of H. Preventing viral diseases MMR Attenuated viruses of Measles, Mumps, Rubella Varicella-Zoster (Chickenpox) Attenuated virus of Herpes-Zoster Salk (Sabin) polio vaccine Polio, inactivated/attenuated virus HDCV

Medical use of antibodies

•Monoclonal antibodies are better suited for medical use as they have higher specificity than polyclonal antibodies and they are less likely to cross-react with human antigens. •Out of all monoclonal antibodies, humanized antibodies are the best for medical use, as they do not trigger immune response in patients and can be used multiple times in the same patient.

PAb production

•Organism is injected with antigen multiple times - according to standard protocol for immunization •In due time, blood is drawn from immunized organism •Antiserum is isolated from collected blood of immunized animal. If desired, IgG (main class of antibody) fraction can be purified from antiserum •After boost immunization, another batch of antiserum can be drawn from time to time using vacutainers

Hypersensitivity II

•What is type II hypersensitivity? Type II hypersensitivity is an immune response in which host cells are damaged due to antibodies binding to the cell surface. This video discusses five mechanisms of cellular damage, including via the complement pathway, opsonization and phagocytosis, and antibody-mediated cellular dysfunction.

Hypersensitivity III

•What is type III hypersensitivity? Type III hypersensitivity describes when antigen-antibody complexes deposit in the blood vessels and cause subsequent inflammation and tissue damage. This video covers the pathophysiology, as well as several important clinical examples of type III hypersensitivity.

Hypersensitivity IV

•What is type IV hypersensitivity? Type IV hypersensitivity is a T-cell-mediated hypersensitivity, meaning the inflammation and potential tissue damage is caused by either T helper cells (CD4+) or T cytotoxic cells (CD8+). This video covers the pathophysiology, symptoms, and several examples, including contact dermatitis as with poison ivy, as well as several other systemic diseases.

A monoclonal antibody suspension

is produced by immortalized B cells.

Polyclonal antibodies

•They are antibodies produced by plasma cells descended from various naïve B cells •They are polyvalent or they can recognize various epitopes of the same antigen They are produced either in human volunteers or laboratory animals like goats, rabbits etc

Properties of monoclonal antibody

•They are called monoclonal as they contain the antibody produced by single clone of plasma cells descended from single naïve B-cell. •These antibodies can recognize only single epitope •Therefore, they are less likely to cross-react with other antigens, including human cells and tissues.

Properties of polyclonal antibody

•They are called polyclonal as they are mixture of antibodies produced by different clones of plasma cells descended from various naïve B-cells. •These antibodies can recognize various epitopes on the same antigen •Therefore, are more likely cross-react with other antigens. •Polyclonal antibodies are produced by injecting antigen into volunteers or lab animals.

Primary immunodeficiency disorders

•They are inborn or congenital and are resulting from genetic defects (mutations). •Examples: •Selective Ig A deficiency - little or no Ig A produced (other antibody classes are not affected) due to mutations in chromosomes 6, 14 or 18. As a result, activated B cells cannot develop into plasma cells producing IgA class antibodies. This is the most common immunodeficiency disorder - it occurs in 1 out of 700 people; •Agammaglobulinemia - few or no antibodies produced due to mutation in X chromosome and inability B cell mature to naïve B cells. This type of immunodeficiency disorder occurs in 1 out of 50,000 people; •Severe combined immunodeficiency disorder (SCID) - Defects in bone marrow stem cells occur due to mutation in the gene localized on X chromosome that encodes common gamma chain shared by various interleukin receptors. As a result, both B and T lymphocytes are not functional. This type of disorder found in 1 out of 500,000 live births. •Stem cells can be obtained from fetal material (fetus) and they have ave almost unlimited capacity to divide, can differentiate into different tissues, may be used to test he effects of drugs on human cells

Monoclonal antibodies

•They are produced by plasma cells descended from single naïve B cell •They are monovalent or they can recognize single epitope of the antigen −They are more specific and less likely to have cross-reactivity than polyclonal antibodies •They are produced in specific cell cultures called hybridomas

Systemic allergic reaction

- It involves Ig E localized on basophils It can be cause by −Most common cases associated with - peanuts, bee stings, penicillin injections −Less common cases - aspirin, ibuprofen, shellfish, milk, eggs, ants, bedbugs, wasps •Allergen enters blood and triggers the release of inflammatory mediators by circulating basophils. •Massive vasodilation leads to blood pressure ↓ & shock

Localized allergic reaction

- It involves Ig E localized on mast cells -Hives (urticaria) •Ingested allergen is absorbed into blood stream and delivered to the skin, •mast cells degranulation results in localized inflammation reaction - known as wheal and flare -Asthma

Autoimmune diseases

- are damaging immune responses directed against self-antigen (or auto-antigens) of its own cells and tissues. They can be induced by: •Injury - when internal parts of the body, normally shielded from immune system, become exposed to it and trigger immune response. Examples: Rheumatoid arthritis •Infection - when infections are caused by microbes that induce production of antibodies that are cross-reacting with human antigens. Examples: Rheumatoid arthritis EXTRA: See Appendix 2 to lecture 7 •Imperfect clonal deletion of naïve B cells during maturation of immune system in developing fetus. Examples: Type I diabetes mellitus

Immunodeficiencies

- are insufficient immune responses to foreign antigen or inability to mount the immune response at all. They can be of two types: •Primary - occur due to mutations in the genes involved in encoding components of immune system. Examples: selective Ig A deficiency, agammaglobulinemia, severe combined immunodeficiency disorder (SCID) •Secondary - occur when an individual is exposed to unfavorable living conditions, including malnutrition and pollution, or infected with certain microbes. Examples: AIDS as a result of HIV infection

Type IV: delayed-type cell-mediated

- caused by hyper-reaction of T cytotoxic cells that were sensitized in previous exposure to the allergen. No antibody involved. •Allergen directly binds to T helper and T cytotoxic-cells previously activated −This type of allergy does not involve antibodies. •Cell-mediated reactions peak in 2 to 3 days after exposure

Please select all statements that apply to hemolytic disease of the newborn to test your understanding of this disorder.

-Fetal RBC leakage sensitizes the mother to make anti-Rh antibodies. -Anti-Rh antibodies that are IgG can cross the placenta and induce complement-mediated lysis of fetal RBCs. -Hemolytic disease is a type II hypersensitivity reaction. Rh+ fetal cells possess an antigen that the mother's cells do not possess, so release of Rh+ fetal RBC into maternal circulation results in sensitization (synthesis of anti-Rh IgM). Each of the subsequent Rh+ pregnancies of this mother are at risk for hemolytic disease because a secondary exposure produces anti-Rh IgG, which can cross the placenta and cause complement-mediated fetal RBC lysis (type II hypersensitivity reaction). Rh+ fetal cells possess an antigen that the mother's cells do not possess, so release of Rh+ fetal RBC into maternal circulation results in sensitization (synthesis of anti-Rh IgM). Each of the subsequent Rh+ pregnancies of this mother are at risk for hemolytic disease because a secondary exposure produces anti-Rh IgG which can cross the placenta and cause complement-mediated fetal RBC lysis (type II hypersensitivity reaction).

HIV Risk factors:

-Herpes infection; -Promiscuous unprotected sex; -Injected drug use

Hemolytic disease of newborn

-It involves surface protein of RBC - Rh (rhesus) factor and IgG antibodies -It occurs when Rh - mother second time becomes pregnant with Rh+ children -At the time of first delivery of Rh- positive child, Rh-negative mother become sensitized to Rh factor and produces anti-Rh antibody (IgG) -During second pregnancy with Rh+ child, maternal anti-Rh antibody is crossing placenta & is attacking RBC of fetus causing hemolytic disease -Prevention- Use of immunosuppressive pills (Rho-GAM) at 26-28 weeks of pregnancy

Which of the following statements about normal skin microbiota are TRUE?

-Members of the normal microbiota protect the skin from colonization by pathogens. -Acne can be caused by opportunistic skin normal microbiota. -Body odor can be caused by the metabolic by-products of some normal microbiota. -Some normal microbiota species of the skin are obligate anaerobes.

Please select the TRUE statements about lymphocyte disorders.

-People with defects in their late complement system components are at risk for repeated Gram-negative bacterial infections. -People with selective IgA deficiency are at risk for repeated infections of the respiratory tract. -Children with DiGeorge syndrome are at risk for virus and obligate intracellular bacterial infections This is true. Recall that IgA is found in mucous. People lacking this antibody are at rsk of respiratory, gastrointestinal and genitourinary infections because the mucous membranes of these tracts are not well protected. This is true. Recall that T cells are involved in the destruction of host cells with intracellular parasites.

Select reasons that you think might prevent a person being treated for TB from being compliant with their medication regime.

-They may not have easy access to the medications and even if they do, they may not be able to afford them. -People often stop taking medications when they feel better and in the case of TB, most people start to feel better after a few weeks. This is true, especially in some developing countries.This is true. When people feel better, they often do not see the need for continuing a medication. This happens quite a bit in the case of TB because the drugs are supposed to be taken for several months.When medications are developed, their effectiveness (benefit) versus their risks are assessed. If a medication has more risk than benefit, it does not make it to market. The idea that medications are always toxic and bad for one is incorrect.Please read the article again. Is this information true? TB medications are actually typically given as pills.This is definitely not true. M. tuberculosis divides very slowly and can also go dormant. It takes months of treament to destroy all of the organisms.

According to this CDC letter: 1) Where Zoe had contracted chickenpox? 2) What was the reason for Zoe to be rushed to hospital and to stay there for a week? 3) What was the reason for Zoe to stay home for another week after she was released from hospital?

1) It is unknown where Zoe was exposed to chickenpox. 2) Infection of blisters with Staphylococcus aureus had aggravated Zoe's state so severely that she had to be rushed to hospital and had to stay there for a week. 3) Since the chickenpox blisters were not healed after one week stay at hospital, Zoe had to stay an extra week at home to prevent her exposure to anything that can cause another infection.

According to this CDC letter: 1) What are possible complications from chickenpox vaccine? 2) What are benefits from chickenpox vaccine?

1. Possibity of side effects such as soreness at the injection site, rash, seizure (rare, caused by fever), in very rare situations people with severe rash can infect others in the household 2. It helps to prevent very serious chickenpox cases (decreasing chances of hospitalization and death), protects children from adults carrying chickenpox (disease is more serious in children), avoids pain and missed school/work. Prevents chickenpox pneumonia

Type III: immune complex-mediated

1. Soluble antigen triggers production of specific antibodies 2. Immune complexes are formed of soluble antigen and produced IgG antibodies 3. Persistent immune complexes activate compliment. This leads to vasodilation and entrapment of immune complexes in the walls of blood vessels 4. Vasodilation and entrapped immune complexes attract neutrophils and basophils. Upon arrival, these cells release proteases 5.Released proteases erode the wall of blood vessels. In turn, this initiates blood clotting mechanism. Clots obstruct blood flow causing necrosis Example: Post-streptococcal glomerulonephritis can develop if streptococcal infection is left untreated. It may lead to kidney failure. The exact nature of antigen produced by Streptococcus pyogenes is unknown.

Slowing the spread of microbial drug resistance

1.Responsibilities of physicians and healthcare workers •Increase the efforts to prescribe antibiotics for specific organisms, ‒Prescribe only when they are really needed. •Educate the patients on proper use of antibiotics ‒Explain consequences of skipping the dose or stopping antibiotics course before it is completed 2.Responsibilities of patient •Follow instructions carefully and complete the prescribed course ‒Misuse of antibiotics leads to microbial resistance 3.Importance of public education •Educate public about limitations and appropriateness of antibiotics use 4.Impact of non-medical use of antibiotics Stop the use of antibiotics as additives to animal and bird feeds

Characteristics of antimicrobial medications

1.Selective toxicity •It is expressed as THERAPEUTIC INDEX: TI = Minimal [toxic to human] / Minimal [toxic to microbe] 2.Antimicrobial action •Does it inhibit the growth or to kill the microbe •What are the drug's targets in a microbe 3.Spectrum of activity •Ability of drug to affect the range of microbes: Broad-spectrum and Narrow-spectrum 4.Effects of combinations •Combination of drugs may increase (synergism) or reduce (antagonism) their effect 5.Pharmacokinetics •Rate of absorption, Tissue distribution, •Metabolism (stability in body), Rate of excretion 6.Resistance to the drug •Innate resistance (mycoplasma resistant to penicillin) •Acquired resistance (mutation or gene acquisition) 7.Adverse effects •Allergic reactions, Toxic effect, •Suppression of normal flora

Exposure to poison ivy, Latex, Nickel in metal jewelry, Chromium in leather

1.Symptoms - Large burning and itching localized rash or irritation of skin that takes few days or weeks to heal. 2.Causes - exposure (direct contact) of skin to allergen 3.Pathogenesis - it is similar to that of TB test, but involves different allergens 4.Prevention - allergy testing for identification of allergen and avoiding it in the future. 5.Treatment - immediate washing of the contacted skin with soap and cold water; Application of weak acid solutions (lemon juice, vinegar); Oral antihistamines (like Benadryl) and corticosteroids (hydrocortisone cream) -boils or blisters

What proportion of the students with physician-confirmed skin infections had either fungal infections or MRSA?

10.8%

Hydramacin is a protein that is 60 amino acids long. How many nucleobases would the mRNA encoding hydramacin have?

180 Each amino acid is encoded by a codon of 3 mRNA bases, so this would be 180 bases

Please label the figure to show your understanding of disease progression in people infected with HIV. Not all labels are used.

1st section acute retroviral syndrome flu-like symptoms may occur, HIV infection spreads through the body 2nd section Clinical latency asymptomatic interval 3rd section AIDS lymph node enlargement, fever, weight loss, fatigue, diarrhea, etc HIV-2 and ART are not placed on this figure. The figure shows disease progression, not virus type of treatment.

Place the following in the order they are used in the indirect ELISA test. 1 = enzyme-linked antibody 2 = known antigen 3 = patient serum 4 = substrate

2, 3, 1, 4 The known antigen is adsorbed to the well. Next, the patient serum is added and the well is rinsed. The indicator enzyme linked to a secondary antibody is added, followed by its substrate. A color change may or may not occur—it depends on whether the patient's serum had the antibody to the known antigen present.

What percentage of the students who participated in the January tournament reported physician-confirmed skin infections after the competition?

22.0%

How could you positively identify the presence of Helicobacter pylori infection without testing blood, feces or biopsy?

?? Blood Tests Blood tests are used to measure antibodies to H pylori. Antibodies are proteins made by the body's immune system when it detects harmful substances such as bacteria. Blood tests for H pylori can only tell if your body has H pylori antibodies. It cannot tell if you have a current infection or how long you have had it. This is because the test can be positive for years, even if the infection is cured. As a result, blood tests cannot be used to see if the infection has been cured after treatment. Stool Test A stool test can detect traces of H pylori in the feces. This test can be used to diagnose the infection and confirm that it has been cured after treatment. Biopsy A tissue sample, called a biopsy, is taken from the stomach lining. This is the most accurate way to tell if you have an H pylori infection. To remove the tissue sample, you have a procedure called endoscopy. The procedure is done in the hospital or outpatient center. Usually, a biopsy is done if endoscopy is needed for other reasons. Reasons include diagnosing the ulcer, treating bleeding, or making sure there is no cance

Shigella has ID50 = 10 and number of reported shigellosis cases in decline. Salmonella has ID50 = 106 and number of reported salmonellosis cases is increasing. Why is the number of reported salmonellosis cases increasing in the USA?

??? Although a conclusive root cause could not be identified, several potential contributing factors to the 2020 red onion outbreak were identified, including a leading hypothesis that contaminated irrigation water used in a growing field in Holtville, CA may have led to contamination of the onions

What types of bacteria do you expect to find on the skin? •Aerotolerant, Facultative anaerobes, Microaerophiles, Obligate aerobes, or Obligate anaerobes?

??? aerotolerant Facultative anaerobe Microaerophiles Obligate anaerobe Obligate aerobe

Which of the following is considered a secondary case of CA-MRSA in this study?

A person who had not recently been tattooed but who contracted MRSA from close contact with another MRSA-infected individual.

What are 2 reasons for occurrence of most TB cases in coastal areas? Can you think of third reason?

A range of factors that disproportionately affect migrants and ethnic minorities, including genetic susceptibility, vitamin D deficiency and co-morbidities such as diabetes mellitus and HIV, also increase vulnerability to infection with Mycobacterium tuberculosis (M. tb) or reactivation of latent infection. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5349312/ https://ejmcm.com/article_1696_96444b45460f59cd5487ef6fdcb7de85.pdf

Why was the ELISA assay used to determine if patients had contracted hepatitis C?

All of the choices are correct Because ELISA shows antibodies against an infectious agent before symptoms begin to show in the patient. So patients showing a positive result could be treated immediately. It allows screening of many patients simultaneously. It is an extremely sensitive assay. ELISA is a very powerful serological test that shows the presence of antibodies even before a patient begins to show symptoms (a situation that is not common for most diseases but can be true for chronic infections like HIV and HCV). The direct ELISA can also identify patients who already have disease and therefore will already have antibodies against HCV. This is important for patients who have been infected with microbes such as hepatitis C or HIV so that treatment can begin as soon as possible.

Which of the following does NOT describe an anaphylactic response?

Allergen route of entry is always due to inhalation. Systemic anaphylaxis is characterized by sudden respiratory and circulatory disruption that can be fatal in a few minutes. In humans, the allergen and route of entry are variable, though bee stings and injections of antibiotics or serum are implicated most often. The concentration of chemical mediators and the strength of the response are greatly amplified in systemic anaphylaxis as compared to cutaneous anaphylaxis. Upon secondary exposure to allergen, the immune system responds with a sudden, massive release of chemicals into the tissues and blood, which act rapidly on the target organs.

Allergies (also called hypersensitivities)

Allergies •They are damaging immune responses to usually harmless foreign antigens, which are called allergens Allergies occur in individuals who were previously exposed to allergen. Immune system over-reacts to appearance of allergen and causes extensive damage to the organism. There are four types of allergies: •Type I or IgE-mediated allergy involves IgE class antibodies localized on mast cells or basophiles. Examples: hives, hay fever, asthma, anaphylaxis •Type II or Antibody-dependent cytotoxic allergy involves IgG, IgM antibodies + Phagocytes and Natural killers or MAC formation. Examples: transfusion reactions, hemolytic disease of newborn •Type III or Immune complex-mediated allergy involves IgG class antibodies that have formed immune complexes with soluble antigen that are persisting in blood stream. Examples: glomerulonephritis, disseminated intravascular coagulation, Arthus reaction, Serum sickness •Type IV or Delayed cell-mediated allergy involves only previously activated T cytotoxic or T helper cells. No antibodies are involved. Examples: Mantoux test, contact dermatitis, rejection of transplants

According to MMWR - 2004-52-1285 article: What were antibiotics that this individual had received in the first seven days? What are their mechanisms of action?

Amoxicillin was a first antibiotic prescribed to the patient. It is bactericidal antibiotic that inhibits the synthesis of bacterial cell wall. It was prescribed with clavulanate potassium (it is not antibiotics) that stabilizes amoxicillin by inhibiting the activity of beta-lactamases. On 4th-7th days patient was receiving multiple antibiotics including: Azithromycin (inhibits protein synthesis); Ceftriaxone and Nafticillin (both are inhibiting the synthesis of bacterial cell wall).

Which of the medications tested in the above image is/are a beta-lactam antibiotic(s)?

Ampicillin Ampicillin is a semisynthetic penicillin that targets the cell wall.

Lect 11 Glossary

Antibiotic-associated diarrhea - it is a complication of taking antimicrobial medications •Bile - it is a fluid produced by the liver that aids in the digestion and absorption of fats •Cirrhosis - it is a damage to the liver that interferes with liver function •Dysentery - it is serious form of diarrhea accompanied by blood, pus, and mucus in the feces •Gastroenteritis - it is acute inflammation of the stomach and intestines characterized by nausea, vomiting, diarrhea, and abdominal pain •Gingivitis - it is inflammation of the gums •Hemolytic uremic syndrome (HUS) - it is serious condition

In this case, what did the ELISA detect?

Antibodies ELISA was used to detect antibodies to hepatitis C virus in the blood to determine if a patient has been or is currently infected with HCV.

Type II: antibody-dependent cytotoxicity (mechanism)

Antibody (IgG or IgM) binds to the cell surface triggering the following: •Antibody-dependent cellular cytotoxicity (ADCC) - Fc domain of cell-bound antibody is recognized by natural killers or macrophages (see lecture 5)

______ are molecules that can specifically bind with antibodies, B-cell receptors and T-cell receptors.

Antigens Antigens are substances that induce an immune response.

Please select all of the statements that illustrate examples of the first-line defenses present in the skin.

Antimicrobial peptides, which disrupt membranes of bacteria. Low pH of sebum, which makes skin inhospitable to most microbes. Lysozyme, which breaks down peptidoglycan. Keratin, which prevents microbe penetration. Sloughing of skin, which removes attached microbes.

Please choose the class of antimicrobials that would have the most selective toxicity.

Antimicrobials that inhibit cell wall synthesis. Antimicrobials that inhibit cell wall synthesis have the most selective toxicity. This is because eukaryotic cells don't have a peptidoglycan (cell wall) synthesis pathway. The bacterial enzymes in the cell wall synthesis pathway can be successfully inhibited without inhibiting any pathways in the host.

Why were the clients with bacteremia give intravenous vancomycin?

Bacteremia means the MRSA was in their bloodstream, necessitating IV medication.

What are possible mechanisms of microbial resistance to b-lactams?

Bacterial resistance to beta-lactam antibiotics includes modification of porins (permeability barrier) and of targets (low affinity of PBP's for the drug), production of inactivating enzymes (beta-lactamases) and inhibition of release of autolytic enzymes. Resistance to β-lactam antibiotics predominantly occurs through one of two mechanisms: 1) the production of β-lactamases, which is the most common resistance mechanism in Gram-negative bacteria, or 2) the production of an altered PBP with a lower affinity for most β-lactam antibiotics. Bacteria can become resistant to penicillin by modifying enzymes that make the cell wall. Some bacteria, including Streptococcus phenominae, have developed resistance to β-lactams through modification of their penicillin binding proteins (or PBPs), which make up the active site of transpeptidase enzymes.

Why are dialysis patients particularly susceptible to blood-borne infections?

Because their blood is processed in a dialysis machine that could be the source of infection. The process of dialysis involves removal of the patient's blood and processing through a dialysis machine. This frequent transfer of blood is a potential source for blood-borne infections.

How is hepatitis C spread?

Blood-to-blood contact hepatitis C is spread through blood-to-blood contact, usually through blood products or through sharing needles.

Based upon the information in the case, hydramacin can be classified as what type of antibiotic?

Broad spectrum Hydramacin appears to be effective against both Gram-positive and Gram-negative bacteria making it a broad spectrum antibiotic.

Which of the statements about Clostridium tetani and tetanus pathogenesis are TRUE?

C. tetani produces a potent neurotoxin that spreads systemically Treatment of a person with tetanus includes tetanus immune globin (TIG), antibiotics, and tetanus toxoid. Tetanus can be diagnosed by signs and symptoms.

In order to bind to a host cell, the spikes of HIV have to attach to ______.

CD4 and a coreceptor The virus must bind to a complex made of both CD4 and a coreceptor found on helper T-cells and macrophages.

Please match the exotoxins with their effect on the host.

Capsule: External component that aids in avoiding phagocytosis Clumping factor: Facilitates attachment to fibrinogen-coated indwelling devices Coagulase: Causes clots in capillaries Leukocidin: Kills neutrophils Proteases: Degrade collagen and tissue components Protein A: Interferes with opsonization and phagocytosis α-toxin: Makes holes in host cell membrane

Please select all of the statements that are TRUE of impetigo.

Causative organism can be Staphylococcus aureus or Streptococcus pyogenes. The disease can be transmitted by both direct contact and indirect contact.

Inhibition of nucleic acid synthesis

Ciprofloxacin •It irreversibly inhibits DNA synthesis •Particularly, it inhibits DNA gyrase and a variety of other enzymes playing role in replication of bacterial DNA •Class - fluoroquinolones. •EXAMPLES: of other antibiotics from this class are Gemifloxacin, Levifloxacin •It is bactericidal antibiotic as it irreversibly binds to DNA gyrase and other enzymes of DNA synthesis. •It is broad spectrum antibiotic that effective against Gram-positive, Gram-negative and Acid-fast bacteria •Side effects: due to serious side effects, including increased risk of cancer, its medical use is limited to treatment of tuberculosis. •Bacterial resistance: Genetic mutations leading to changes in targeted enzymes. Microbial resistance can develop rapidly, even during a course of treatment. Rifampin (Rifampicin) •It irreversibly inhibits RNA synthesis •Particularly, it inhibits RNA polymerase involved in synthesis of RNA new strand •Class - rifamycins. •EXAMPLES: of other antibiotics from this class are Rifabutin, Rifaximin •It is bactericidal antibiotic as it irreversibly binds to RNA polymerase and inhibits RNA synthesis. •It is broad spectrum antibiotic that effective against Gram-positive, Gram-negative and Acid-fast bacteria. •Side effects: Due to high toxicity, it's medical use is limited to treatment of tuberculosis, leprosy and prophylaxis of meningitis in people exposed to Neisseria meningitidis. •Bacterial resistance: Genetic mutations leading to changes in targeted enzymes.

From where did the secondary cases contract MRSA?

Close contact with a MRSA-positive person.

Lower Digestive System Infections

Common characteristics of bacterial infections of LDS Signs and symptoms •Incubation period - 2 days or less •Loss of appetite, Nausea, Vomiting, •Diarrhea •Sometimes fever Etiological agents •Most of the bacterial infections caused by enteric bacteria (Enterobacteriaceae family) ‒Members of the following genera: Escherichia, Salmonella, Shigella etc Pathogenesis •Bacteria attach to epithelium using adhesins localized on pili •Some microbes are using Type III secretion system to manipulate intestinal cells and invade them •Enterotoxins are causing intestinal cells to loose water and electrolytes leading to diarrhea Epidemiology •Transmission occurs via fecal-oral route involving water or food contaminated with animal or human feces •Pathogens are sensitive to acid & have much higher infectious dose than acid-resistant bacteria •Low gastric acidity is a risk factor Prevention & Treatment •Oral rehydration therapy; Antibiotic treatment is usually not recommended •Hand washing; Control of water & food supply •Very few vaccines available, they are not effective Common characteristics •It starts within 2 days of exposure with loss of appetite, nausea, vomiting followed by diarrhea. •Infections are mainly caused by enteric bacteria of genera Escherichia, Salmonella, Shigella. They use adhesins localized on pili to bind to epithelium. •Produced enterotoxins cause the loss of electrolytes and fluids by in host. •Infections transmitted via fecal-oral route. •Most microbes are sensitiive to acid and have high infectious dose. •Infections can be prevented by hand washing, sanitary control of water and food supply. •Treatment usually include oral rehydration therapy only. Properties of bacterial family of Enterobacteriaceae •Gram-negative facultative anaerobic bacilli •They can ferment lactose with production of lactic acid and gas. •They are tightly associated with intestines of humans and animals •Enteric bacteria include species of Escherichia, Salmonella, Shigella,

According to this CDC letter: What are possible complications from chickenpox?

Complications from chickenpox include infected blisters, pneumonia, bleeding disorders, brain swelling (encephalitis), some times it can lead to death. Before introduction of chickenpox vaccine, about 11,000 people were hospitalized and about 50 children and 50 adults died every year from chickenpox in the USA alone.

According to MMWR - 2004-52-1285 article: What was the main reason that the treatment was ineffectual and patient has died of diphtheria?

Diphtheria antitoxin (DAT) was administered only on the 9th day of the illness. This DAT administration delay resulted in the death of a patient despite the fact that he was receiving multiple antibiotics.

Upper Digestive System Infections

Dental caries (tooth decay) Periodontal disease Helicobacter pylori gastritis Mumps

Prevention & Treatment (allergies)

Desensitization - procedure that causes immune system to produce more IgG against allergen Treatment - Epinephrine (adrenaline), intravenous fluids, anti-histamines and steroids. Omalizumab

Please place the following events in the correct order to test your understanding of the mechanism of action of desensitization or "allergy shots."

Diluted but gradually increasing concentrations of pure allergen are injected. (1) Degranulation of mast cells is prevented. (4) Allergen-specific IgG antibodies are produced by B cells. (2) IgG binds to allergen before it can bind IgE. (3) One theory suggests that injection with dilute but gradually increasing concentrations of allergens stimulate the formation of high levels of allergen-specific IgG instead of IgE. Then these IgG-blocking antibodies remove allergen from the system before it can bind to IgE, thus preventing the degranulation of mast cells.

the ______ of the zone of inhibition is always measured in ______.

Diameter, mm The diameter of the zone of inhibition is measured in millimeters (mm) to determine susceptibility to antimicrobial agents.

During incubation, antimicrobials applied to the bacterial lawn become increasingly ______ as they diffuse out of the disc into the medium.

Diluted The antimicrobial agents move from a high concentration on the disc to a lower concentration within the medium via diffusion.

An ELISA to detect the hCG hormone, elevated during pregnancy, would be classified as a(n) ______ ELISA.

Direct A pregnancy test detects the presence of the antigen, hCG hormone, and therefore is a direct ELISA.

Staphylococcal food poisoning

Disease is caused by ingested temperature-resistant enterotoxin that acts as super-antigen (type I exotoxin) 1. Food cooking kills all microbes 2. Unsafe handling contaminates food with S. aureus 3. If food kept at room temp., S. aureus grows & produces toxin 4. Heat-stable toxin survives food reheating 5. Food with toxin is consumed Staph intoxication in 1 to 6 hours To prevent S. aureus growth, the cooked & prepared food must be stored at 4OC or at 55OC or higher. Staphylococcus aureus •It can survive at higher temperatures, up to 55OC for up to 30 minutes •It is halophilic bacterium that survives high salt and high sugar concentrations •Temperature-resistant super-antigen of S. aureus is causing toxic shock. •Massive release of histamine, interleukins etc. •Resulting in drop of blood pressure that may potentially lead to disseminated blood clot formation

Etiological agent

Disease is developing due to infection by Human Immunodeficiency Virus (HIV-1 or HIV-2) •Enveloped retrovirus. Capsid has two copies of ss(+)RNA genome and 3 viral enzymes

Which assay was used to confirm the patients' diagnosis in this case?

ELISA ELISA was used to screen patient sera for antibodies to the fungus.

Examples of microbial resistance to antibiotics

Enterococcus Part of normal intestinal flora; Common cause of nosocomial infections; Strains resistant to vancomycin - VRE (vancomycin resistant enterococcus Mycobacterium tuberculosis Microbe is often resistant to one of the multiple drugs used to treat infection When organisms become resistant to rifampin and isoniazid they are termed multi-drug-resistant or MDR-TB. Klebsiella pneumoniae - see also MMWR reports listed in slide notes Recently appeared strains are highly resistant to treatment by carbapenem Staphylococcus aureus Most strains had acquired resistance to penicillin due to acquisition of penicillinase genes Many strains become methicillin-resistant (MRSA) due to mutations in penicillin-binding protein Some strains become vancomycin intermediate (VISA) and vancomycin resistant (VRSA) due to mutations in side chains of peptidoglycan Antibiotics: •Carbapenem is broad-spectrum antibiotic of b-lactam antibiotic family, highly resistant to most b-lactamases. •Methicillin is chemically modified penicillin that is penicillinase-resistant •Vancomycin inhibits bacterial cell wall synthesis by binding to peptidoglycan side chains. •VISA - infection can be treated if antibiotic concentration is increased 2-3 fold. •VRSA - infection is treated if antibiotic concentration is increased > 3-5 fold •Macrolides - is a class of bacteriostatic antibiotics that interfere with protein synthesis. It includes Erythromycin, Azithromycin, Clarithromycin.

Please match the different types of antiretroviral medication with their mechanism of action.

Entry inhibitors --> Prevent access to co-receptor CCR5 or prevent fusion of viral envelope with host cell membrane. Reverse transcriptase inhibitors --> Prevent synthesis of DNA copy from the viral RNA genome. Integrase inhibitors --> Prevent integration of the DNA copy of the HIV genome into the host cell genome. Protease inhibitors -->Prevent cleavage of viral polyproteins into individual proteins, thus inhibiting virions from maturing.

Which of the following is NOT a class of antiretroviral medications currently available for HIV-positive individuals?

Envelope inhibitors

Inflammation of which of the following parts of the upper respiratory tract is/are potentially life-threatening?

Epiglottis Epiglottitis is potentially life-threatening because the swollen flap may block the airway.

Respiratory system lined by mucous membranes

Epithelial cells form continuous anatomical barrier Mucous (goblet) cells produce mucus Ciliated cells remove mucus and trapped microbes

Please match the disease with the description of the characteristic rash with which it is associated.

Erythema migrans -- Lyme disease Rash on palms and soles -- Rocky Mountain spotted fever "Slapped face" rash -- Fifth disease Fine red rash, starting on face -- Rubeola Rash with fluid-filled vesicles -- Varicella

The causative agent of histoplasmosis belongs to which domain(s) of life?

Eukarya Histoplasmosis is caused by Histoplasma capsulatum, which is a eukaryotic fungus.

T/F Condoms provide 100% protection against all sexually transmitted infections

False

Types of the skin diseases

Exogenous Pathogen enters via breaks in the integrity of the skin -Folliculitis, -Impetigo, -Necrotizing fasciitis •Abscess forming, non-contagious - Folliculitis; Furuncles; Carbuncles •Spreading infections, contagious - Impetigo; Rocky Mountain Spotted Fever; Lime Disease; Superficial cutaneous mycoses •Necrotizing infections causing necrosis - Necrotizing fasciitis; Gas gangrene Endogenous Pathogen enters the skin from underlying tissue or carried by blood or lymph -Rashes due to Varicella, Measles, Rubella, Toxin-induced •Abscess formation - from endocarditis caused by Streptococcus aureus •Rashes - caused by various viral infections •Necrosis - Purpura fulmaris due to chronic meningococcemia Toxin-induced Pathogen infects place distant from the skin, toxin produced is delivered to the skin. -Scalded skin syndrome •Scalded Skin Syndrome •Toxic Shock Syndrome

T/F. Please determine whether the following statement is true or false: "The influenza virus is able to decrease the effectiveness of the host immune response by a mechanism called antigenic drift, which involves the reassortment of gene strands with other influenza viruses."

False

T/F/ Corynebacterium diphtheriae is very invasive and can cause direct damage to the heart, kidneys, and nerves.

False

T/F If the Kirby-Bauer assay revealed any zone of inhibition for hydramacin, this would mean that the test organism was sensitive to this novel drug.

False False, the measurement of the diameter of the zone of inhibition would have to be compared to the established range for these values in order to determine if the organism was in fact sensitive to hydramacin.

Fluorescent antibody test

Fc of antibody can be labeled without affecting the specificity of antibody-antigen interaction. Direct labeling Indirect labeling •Specific antibody directed against a microbe is labeled (tagged) with fluorescent dye before it can be used in fluorescent antibody test. •It can be labeled directly (dye is directly attached to antibody) or indirectly (dye is attached to secondary antibody that can bind to primary specific antibody. •Sample is placed on slide and incubated with tagged antibody. •After rinsing, slide examined under fluorescent microscope. •If patient was infected with a microbe, microbe would be stained by antibody and become visible under the microscope.

Type I allergy: immediate IgE-mediated- general mechanism

First exposure to allergen 1. B-cell activation 2. proliferation, cell-class switching to IgE, memory cells 3. Sensitization Next exposure to allergen 4. Cross-linking of cell bound IgE 5. degranulation and release of mediators 6. allergy reaction

Which of the following are ways to avoid catching the common cold?

Frequent handwashing Avoiding touching nose and eyes Avoiding crowded areas Hand washing is a good way to avoid contracting the cold virus. Cold viruses are easily transmitted to the respiratory tract via the eye or nose. Avoiding touching these will help prevent catching a cold. Cold viruses are spread by droplet transmission. Avoiding crowded areas will help reduce risk of catching a cold.

Acquisition of gut flora in infants

Gastrointestinal tract of newborn is sterile After birth, the bacteria from mother and environment colonize the infants, including their digestive systems Colonization of infant's digestive system At the beginning, intestines are colonized by E. coli and Streptococcus spp. In a few days, bacterial count reaches 108-1010 per gram of feces During first week of life, they create environment suitable to other microbes The stomach of newborn is lacking acid! Normal flora of digestive system is affected by a diet In breast-fed babies - Bifidobacterium, Lactobacillus are predominant They are Gram-positive bacteria In formula-fed babies: Bacteroides, Enteric bacteria, Enterococcus are prevailing They are Gram-negative bacteria People with predominantly Gram negative bacteria in their guts have tendency to have extra weight.

HIV prevention

General public Education to increase awareness Safe sex practice Use of condoms is NOT 100% effective Abstinence is the only 100% effective Monogamous relationship reduces risks Not sharing needles/syringes Destroy before placing them in trash Use of PrEP, pre-exposure prophylaxis & testing Particularly if one partner is HIV-positive or there are multiple partners Use of PEP, post-exposure prophylaxis Take it daily for 28 days Health-care workers Use universal precautions: Use of gloves, gowns, masks, goggles, Do not recap needles Use of PEP, post-exposure prophylaxis After potential exposure to HIV take it daily for 28 days Mandatory screening of blood, organ transplants. Report the new cases Vaccines that are in clinical trials: •Whole-cell Salmonella with gp120 gene expressed •Subunit vaccine using gp120 gene expressed in Saccharomyces cerevisiae •Canarypox virus with HIV capsid protein gene •Naked DNA consisting of genes tat (encodes transcription factor) and gag (encodes capsid protein) Potential Use of CRISPR System in Prevention and Treatment of HIV Infections Graph explanation: •Red line - represents the number of people newly infected with HIV world-wide. The number of newly infected was on steady increase until 1997, when it peaked at over 3.5 million people. Since then number of newly HIV-infected people was in decline, dropping to about 2.7 million people in 2008. •Blue line - represents number of deaths from AIDS world-wide. Number of deaths from AIDS as on a rise until 2003, then it leveled off until 2006, and then after it is in decline. This reflects a few facts: •There are less people newly infected by HIV •Substantial progress was made in development of effective antiretroviral drugs •Grey columns - represent number of people living with HIV. The number was on increase until 2005, when it leveled off. This reflects the fact that there are less people newly infected every year.

Corynebacterium

Gram-positive facultative anaerobe, slightly bent non-motile pleomorphic bacillus that form no endospore Corynebacterium diphtheriae It forms metachromatic granules It forms distinctive black colonies on (blood agar + tellurium) It lacks ability to invade human body - always on surface Virulence factors: Diphthin (IgA protease) and Diphtheria toxin (toxin is produced only by strains lysogenic for b virus) •Gram-positive, catalase positive, facultative anaerobe producing no endospore, nonmotile, from rod-to filament-shaped bacteria that are straight or slightly curved. •They are producing some mycolic acid but still are stained purple in Gram stain. •Metachromatic granules are usually representing regions where excess of phosphate is stored. They are revealed by Albert - Ponder stain - different parts of the organism are stained in different colors by single dye (due to pH differences) •The cells are forming characteristic "Chinese letters" growth arrangements •Corynebacterium diphtheriae is normally non-pathogenic and has no virulence factors to penetrate first line of defense •However, upon lysogenic conversion the microbe acquires ability to produce diphtheria toxin (class A-B toxin) that can affects the protein synthesis in targeted cell. •They are producing diphthin, the protease digesting IgA class antibody •This protease helps microbe to survive on surface of mucous membrane but it does not improve microbial invasiveness.

According to MMWR - 2004-52-1285 article: What was the main reason that healthy Pennsylvania man aged 63 had contracted diphtheria?

He had never been immunized against diphtheria and had traveled to Haiti where the disease is endemic.

Which cells possess the receptor complex for gp120, resulting in their destruction and the overall loss of immune function seen in AIDS?

Helper T-cells and macrophages Helper T-cells and macrophages are the cells that have receptors for HIC gp120 and can be infected by the virus.

Hyperbaric oxygen treatment ‒It is effective only for infections caused by Clostridium perfringens - WHY?

If clostridium bacteria are exposed to high amounts of oxygen, their replication, migration and exotoxin production can be inhibited. This is why hyperbaric oxygen is used in the treatment of gas gangrene. Clostridia lack superoxide dismutase, making them incapable of surviving in the oxygen-rich environment created within a hyperbaric chamber. This inhibits clostridial growth, exotoxin production, and exotoxin binding to host tissues

Why is incidence of strep throat peaks in winter / early spring?

Immediate care centers seeing high number of strep throat cases. Strep throat season, which happens during late winter and early spring, is hitting the Louisville area. A sore throat often is considered to be a cold symptom, but allergies, dry air and even acid reflux could cause a sore throat. Strep throat occurs most commonly in children. Time of year. Although strep throat can occur anytime, it tends to circulate in winter and early spring. Strep bacteria flourish wherever groups of people are in close contact. there are two reasons someone may get frequent strep throat: Sheer exposure. This happens a lot when there are outbreaks of Strep in school and is most common in winter and spring months. Also, families with several children tend to pass it around to each other.

If you had to test 75 patients for antibodies to Bacillus anthracis (causative agent of anthrax), which immunoassay would you use?

Indirect ELISA With so many samples to test, you would select an indirect ELISA, which allows analysis of 96 samples at one time.

Viral Infections of Circulatory System

Infectious mononucleosis

The area of clearing around the discs is called the zone of

Inhibition A zone of inhibition is the clear area that develops around a test bacterium sensitive to the applied antimicrobial agent

What is the test organism's level of sensitivity to tetracycline?

Intermediate The zone of inhibition measured 15 mm for this medication, which is classified as resistant to this medication. Less than 14 mm indicates resistance to the medication, while more than 19 mm would indicate sensitivity to the medication.

Artificially acquired immunity

It is resulting from human acts like: •Vaccination - results in ability of body produce its own specific antibody against a microbe •Variolation is vaccination against smallpox. It was originally developed by Chinese, then it was improved by Jenner. He called it vaccination. •Vaccination is more effective and much safer than variolation. •Injection of immunoglobulins produced elsewhere. It does not involve the ability of recipient's body produce its own specific antibody against a microbe

Naturally acquired immunity

It is resulting from natural processes like: •Infection - results in ability of body produce its own specific antibody against a microbe •Transfer of antibody from mother to child - via placenta or via breast milk. It does not result in the ability of child's body produce its own specific antibody against a microbe

Staphylococcal scalded skin syndrome

It is toxin-induced disease - toxin is delivered to skin after it is produced elsewhere Signs & symptoms It starts with nose, mouth and genitalia becoming painful to touch Then, skin becomes red and wrinkled as if it was burned or scalded Skin is felt like sandpaper Large blisters filled with fluid appear everywhere on the body Highly characteristic Nikolsky's sign: epidermis is detaching if skin slightly rubbed with finger Etiological agent Staphylococcus aureus •The disease is caused only by S. aureus strains producing exfoliative toxin Etiological Agent •SSSS is caused by Staphylococcus aureus that is Gram-positive facultative anaerobe that is halophilic and mannitol fermenter. •It is catalase-positive cocci growing in clusters and can produce various virulent factors. •To cause SSSS, S. aureus strain must produce exfoliative toxin that acts as highly specific protease which is targeting desmoglein I, a protein in desmosomes that hold skin cells (keratinocytes) together Pathogenesis •Exfoliative toxin is secreted by Streptococcus aureus at the site of infection •The toxin enters blood stream and it is delivered to the skin •In the skin, exfoliative toxin digests desmoglein I present in desmosomes and expressed mainly in epidermis •As a result, epidermis is split from dermis just below the keratinized outer layer ‒Infected start losing the fluids and become a prime target to secondary skin infections •Mortality rates may reach 40%, if infection is left untreated -The outcome depends on prompt treatment and overall health of the patient •Complications −Secondary infections that are primarily caused by Pseudomonas aeruginosa •Staphylococcus aureus produces exfoliative toxin at the site of infection. •The toxin enters blood stream, it is delivered to the skin and cts as highly specific protease that cleaves desmoglein I, a protein in desmosomes that hold skin cells (keratinocytes) together, and splits epidermis from dermis. •As the epidermis is lost, the infected starts losing the fluids and become prime target for secondary infections, particularly caused by Pseudomonas aeruginosa. •Due to severe loss of fluids and secondary infections, mortality rate may reach up to 40%, if disease is not promptly treated. Epidemiology •Classification: ‒Сontagious, Notifiable disease •Reservoir: ‒Infected humans •Routes of transmission: ‒Respiratory droplets ‒Direct (Hand shakes) Indirect contacts (Fomites) •Statistics: ‒Usually, SSSS occurs in isolated cases. §Still, small epidemics can occur in nurseries ‒The disease is occurring mainly §Infants or elderly §immuno-compromised patients •Contagious, notifiable disease. •Natural reservoir - humans infected with S. aureus strain producing exfoliative toxin •Transmission occurs via direct and indirect contacts •SSSS mainly affects infants, elderly, or immuno-compromised •It usually occurs as isolated cases. However, small epidemics can occur in nurseries Prevention •Quarantine ‒It is the only effective preventive measure against the spread of the disease ‒It is also reducing the risk of getting secondary infections §Secondary infections are caused primarily by Pseudomonas aerogenes •Vaccine ‒NONE •Good hygiene ‒Avoid the crowds and interaction with infected Treatment •Prompt fluids replacement -It is essential for patient's survival •Antibiotic treatment -Semi-synthetic penicillins that are resistant to penicillases §Alternatively, b-lactam antibiotics can be combined with b-lactamase inhibitors -Clindamycin that besides being bacteriostatic, also has some anti-toxin activity •Removal of the dead skin -It reduces the chances of getting secondary infection Clindamycin •It is semisynthetic derivative of lincomycin, a natural antibiotic produced by Streptomyces lincolnensis. Clindamycin has a bacteriostatic effect - it inhibits protein synthesis in bacterial cells

Why is influenza virus has very high mutation rate?

It is well known that the influenza viral RNA-polymerase represents the lack of proofreading function. Thus, the integration of faulty nucleotides often occurs during the viral replication process with a rate of 10−3 to 10−4, which results in high mutation rates [39,40] Influenza A is a genetically labile virus, with mutation rates as high as 300 times that of other microbes. Changes in its major functional and antigenic proteins occur by means of 2 well-described mechanisms: antigenic drift and antigenic shift. It is most pronounced in influenza A viruses. As is the case in all RNA viruses, mutations in influenza viruses occur frequently because the virus' replication machinery does not have a proofreading mechanism.

What is the disadvantage of an antibiotic with a short half-life?

It must be given multiple times daily.

Transfusion reaction

It occurs if wrong type of blood is used in transfusion - mostly involves IgM. - Immune system produce antibody against the wrong red blood cells and kills them

Variolation

It was the method of inoculation first used to immunize individuals against smallpox (Variola) with material taken from a patient or a recently variolated individual, in the hope that a mild, but protective, infection would result.

Please choose the method of antimicrobial susceptibility testing that involves measuring and evaluating zones of inhibition around antibiotic discs placed on a culture of bacteria prior to incubation.

Kirby-Bauer test

Comparison of Signs & Symptoms Varicella (chickenpox) Rubeola (measles) Rubella (German measles)

Lec 10, slide 26

Comparison of epidemiology of varicella, rubeola, and rubella

Lec 10, slide 30 Comparison of epidemiology of varicella, rubeola, and rubella •All three diseases are •Contagious and notifiable. •Have reservoirs in humans. •Transmitted via respiratory droplets and fomites. •There is herd immunity achieved in the US population due to immunization campaign. •Varicella (Chickenpox) •The virus cannot be eradicated as it can turn provirus, •It can cross placenta and cause infections in fetus resulting in congenital varicella syndrome •Rubeola (Measles) •The virus can be eradicated as it does not form provirus •Latest outbreak of measles in the US had occurred in 2014. •It is less likely to cross placenta and cause infections in fetus •Rubella (German measles) •The virus can be eradicated as it does not form provirus •There were no endemic cases were reported in both Americas since 2009. •It crosses placenta and causes infections in fetus resulting in congenital rubella syndrome. Abortion is advised to pregnant women that were exposed to virus and do not have immunity Rubeola •Outbreak can still occur due to : •Children too young to be vaccinated or preschool children never vaccinated •Persons not vaccinated for religious or medical reasons •Over 4 million cases were reported globally in 1980, nowadays about 100,000 cases reported annually •In 2014 there was a major measles outbreak in California involving about 200 people. Rubella •During the epidemic in the U.S. between 1962-1965, rubella virus infections during pregnancy were estimated to have caused 30,000 still births and 20,000 children to be born impaired or disabled as a result of CRS.

Prevention of Varicella, Rubeola, and Rubella

Lec 10, slide 31 Prevention of Varicella, Rubeola, and Rubella •All three diseases can be prevented by immunization. •Chickenpox is prevented by attenuated Varicella-Zoster vaccine. •Measles and German measles are prevented by attenuated MMR vaccines. •Both of these vaccines can be combines into MMRV vaccine. •These vaccines are highly effective (over 90%) and they are part of the US immunization schedule. •Currently, there is about 95% of young children immunized in the USA. •The use of these vaccine is not recommended for immunization of pregnant women. Varicella-Zoster vaccine •The WHO recommends routine vaccination only if a country can keep more than 80% of people vaccinated. If only 20 to 80% of people are vaccinated it is possible that more people will get the disease at an older age and outcomes overall may worsen. Either one or two doses of the vaccine is recommended. •In the United States two doses are recommended starting at twelve to fifteen months of age. As of 2012 most European countries either recommend it for all children or just those at high risk, but not all countries provide the vaccine due to its cost. •The vaccine is very safe. Minor side effects may include pain at the site of injection, fever, and rash. •Severe side effects are rare and occurred mostly in those with poor immune function. Its use in people with HIV/AIDS should be done with care. •It is not recommended during pregnancy. The vaccine is available either by itself or along with MMR vaccine. MMR vaccine •Since introduction of vaccine, occurrences of rubeola and rubella have become rare in the countries with high immunization rates (over 80%). •Vaccination has interrupted the transmission of rubella in the Americas: no endemic cases have been observed since February 2009. •Since the viruses can always be reintroduced from other continents, the population in the USA still need to be vaccinated to keep the western hemisphere free of rubeola and rubella. Treatment of Varicella, Rubeola, and Rubella •There is no treatment of these diseases. Antibiotics may be prescribed to prevent secondary bacterial infections.

Sources of antibiotics chart

Lec 8, slide 18

Normal microbiota of the upper respiratory system (table)

Lec 9, slide 4

Comparison of Etiological agents Varicella (chickenpox) Rubeola (measles) Rubella (German measles)

Lect 10, Slide 27 Varicella zoster virus •It is enveloped virus with double-stranded linear DNA genome. •It can turn into provirus causing latent viral infection. •It can cross placenta causing congenital syndrome. . Rubeola virus •It is enveloped virus with single-stranded linear RNA(-) genome. •Virus gives positive hemagglutination reaction, which can be used in diagnostics •Virus-infected cells are fusing and forming giant multinuclear cells known as Koplik's spots. • Sequence analysis suggested that measles virus most probably appeared in human population around 11th or 12th century AD. •It had diverged from wide-spread in the past rinderpest virus that infects cattle. Rubella virus •It is enveloped virus with single-stranded linear RNA(+) genome. •It can cross placenta causing severe congenital syndrome. It can cross placenta and infect fetus causing congenital rubella syndrome or stillbirth.

Virulence Factors Table

Lect 9, slide 8

New vaccines required chart

Lecture 8 Slide 11

Chart of Attenuated and Inactivated vaccines

Lecture 8, Slide 3

Otitis media

infection of the middle ear

Classification of skin lesions & diseases

Lesion is any damage or change in the tissue of an organism, caused by disease or trauma Lesions •Vesicle is formed during chickenpox •Bulla is formed during bullous impetigo •Pustule is formed during smallpox •Macule is formed during rubella (German measles)

Explain the difference between MIC and MBC.

MIC is the minimum dose of an antimicrobial medication that prevents the growth of an organism, while MBC is the minimum dose of that medication that kills the organism. Recall that MIC is the minimum dose of an antimicrobial medication that prevents the growth of an organism, while MBC is the minimum dose of that medication that kills the organism.

Normal flora of human skin

Microbial species make-up of normal flora on the skin: Fungi (like species of genus Malassezia) (7%), Gram negative (17%), Gram positive - 76% (Actinobacteria 52%, Firmicutes 24% ), Actinobacteria •Corynebacterium •Propionibacterium •Micrococcus •Other Bacteriodetes Cyanobacteria Firmicutes •Staphylococcus •Other Proteobacteria Unclassified Malassezia •It is a genus of fungi. •It is naturally found on the skin surfaces of many animals, including humans. •In occasional opportunistic infections, some species can cause hypopigmentation or hyperpigmentation on the trunk and other locations in humans. Phylum Actinobacteria •It is a group of Gram-positive bacteria that have high guanine and cytosine content in their DNA. • Phylum Bacteroidetes •It includes three large classes of Gram-negative, non-spore-forming, anaerobic, and rod-shaped bacteria that are widely distributed in the environment, including in soil, sediments, and sea water, as well as in the guts and on the skin of animals. • Phylum Cyanobacteria •It includes bacteria that obtain their energy through photosynthesis. • Phylum Firmicutes •It is composed of Gram-positive bacteria with low GC content in their DNA. • Phylum Proteobacteria •It includes 5 classes (a, b, g, d, e) of Gram-negative bacteria.

Which of the following diseases that cause childhood deaths or disabilities are now prevented with successful vaccination?

Measles, Pertussis, Paralytic poliomyelitis, Diphtheria -Measles can cause serious childhood illness, and even death. The MMRV vaccine prevents this disease. P -Pertussis can cause serious childhood illness, and even death. The DTaP vaccine prevents this disease. -Polio can cause serious childhood illness, and even death. The IPV and OPV vaccines prevent this disease. -Diphtheria can cause serious childhood illness, and even death. The DTaP vaccine prevents this disease.

If an immunocompromised child lives in a community in which 97% of people have received the MMRV vaccine, herd immunity is likely to protect the child from

Measles, mumps, chickenpox, german measles -The child will be protected from measles, mumps, rubella and chickenpox. -The child will be protected from measles, mumps, rubella and chickenpox. -The "V" in this vaccine stands for varicella, or chickenpox. The child will be protected from measles, mumps, rubella and chickenpox. -The "R" in this vaccine stands for rubella, also called German measles. The child will be protected from measles, mumps, rubella and chickenpox.

Genetically modified monoclonal antibodies

Mouse antibody. •Constant region of antibody is mouse-specific •The antibody is causing immune response in humans •Monoclonal antibodies can be produced but they can be injected only once in a patient Chimerical antibody. •Constant region of mouse antibody is replaced with ones of human antibody •Immune response to these antibodies is muted in humans •Monoclonal antibodies can be produced and can be injected more than once Human antibody. •Constant region of antibody is human-specific •The antibody is not causing immune response in humans •Monoclonal antibodies cannot be produced Humanized antibody. •Constant and some variable regions of mouse antibody are replaced with human ones •There is no immune response to these antibodies in humans •Monoclonal antibodies can be produced and injected multiple times

Resistance to antimicrobial drugs

Mutation of existing genes 1.Alteration of target molecules Examples: resistance to Sulfa drugs, Rifampin, Ciprofloxacin, Penicillin, Vancomycin 2.Alteration of transport proteins Examples: resistance to tetracycline Bacterial resistance to antimicrobial drugs acquired due to mutation in existing gene •It may occur via spontaneous or induced mutations that leads to resistance due to •Alteration of target molecule so that antibiotic no longer binds to it. •Alteration of molecule responsible in transport of antibiotic in to the cell •EXAMPLES: •Resistance to vancomycin is due to replacement of terminal D-Ala by lactic acid in peptidoglycan precursor's side chain •Resistance to penicillin is due to modification of penicillin-binding protein - PBP type 2a in Staphylococcus aureus •Resistance to tetracyclines may occur due to either reduced drug uptake or Increased excretion rate by microbial cell Resistance to ciprofloxacin, rifampin, sulfa drugs, trimethoprim occur due to mutations in the genes encoding corresponding bacterial enzymes targeted by Acquisition of new genes 1.Alteration of target molecules Examples: resistance to erythromycin due to methylation of 23S ribosomal RNA 2.Alteration of antibiotic molecule Examples: resistance to Chloramphenicol, b-Lactams (including penicillin) Bacterial resistance to antimicrobial drugs due to new genes acquisition •It mainly occurs via transfer of R plasmids between bacterial strains or species leading to •Alteration of target molecule so that antibiotic is no longer binds to it •Alteration of structure of antibiotic leading to antibiotic inactivation •EXAMPLES: •Chemical modification of antibiotic - acetylation of chloramphenicol by newly acquired bacterial acetyl transferase •Digestion of antibiotic - break down of β-lactam ring of penicillins or cephalosporins by newly acquired bacterial penicillase or β-lactamase •Chemical modification of target molecule - resistance to erythromycin due to methylation of 23S rRNA by newly acquired methylase

Common Bacterial Infections

Necrotizing fasciitis (flesh eating disease)

According to MMWR - 2004-52-1285 article: How and when the diphtheria was positively confirmed?

On day 11, pseudomembrane was tested positive for Corynebacterium diphtheriae tox genes by polymerase chain reaction. (Gene tox encodes diphtheria toxin)

According to MMWR - 2004-52-1285 article: What were the treatments on 8th day of illness and after?

On day 8th patient continued to receive multiple antibiotics (penicillin, vancomycin, gentamycin). On day 9th, patient received diphtheria antitoxin (DAT)

What was the likely source(s) of infection at the dialysis center?

Other patients Due to improper disinfection techniques, blood was found on dialysis equipment, chairs, and the floor. The source of the blood was other patients.

Microbial makeup of digestive system normal microbiota

Over 1000 microbial species are living in human digestive system. 40 species make up ~99% of normal flora Most of normal flora is found in large intestines. Microbial species include: 99% of them are facultative or obligate anaerobic bacteria; Fungi; Protists; All together microbes make up to 60% of feces' mass. Bacterial genera found in large intestines Gram negative -Bacteroides -Escherichia Gram positive -Bifidobacterium -Clostridium -Lactobacillus -Peptococcus -Peptostreptococcus -Ruminococcus Benefits of having the normal flora in the guts: Training of immune system, Suppression of harmful bacteria growth Aiding in digestion of carbohydrates Production of vitamins (biotin and K) for the host Production of hormones directing host to store fats Research data: Rodents grown in sterile conditions and lacking gut flora had to consume 30% more calories just to maintain the same weight as their counterparts that have microbes in intestines Benefits of normal flora •Normal flora (NF) can: 1.train immune system of the host upon accidental exposure as some antigens may be shared with pathogens. 2.suppress the growth of harmful microbes by masking binding sites, by using up of available nutrients, or even by direct killing of pathogens. 3.increase the effectiveness of food digestion and nutrient extraction. 4.produce vitamins that are required but not produced by the hosts (for example, E. coli is producing biotin and vitamin K). 5.produce hormone-like molecules that affect metabolism of the host and direct the body to store more fat. Effect of normal flora makeup on body weight •In skinny people, Gram-positive bacteria prevail, while in people with excessive weight Gram-negative bacteria are prevailing •It has been shown that microbes can affect the effectiveness of carbohydrate fermentation and synthesis of fatty acids in host organisms •Rodents grown in sterile conditions and lucking gut flora had to consume 30% more calories just to maintain the same weight as their counterparts that have bacteria in intestines.

PCV13 vaccine is conjugated vaccine and triggers immune response in young children. WHAT might be the reasons for not using PCV-13 vaccine in immunization of young children?

PCV13. Young children who get PCV13 at the same time as inactivated flu vaccine may be at increased risk for seizures caused by fever. Because PCV13-type disease is at historically low levels among adults ≥65 years and most pneumococcal disease among these adults is due to non-PCV13 serotypes, ACIP no longer recommends their routine vaccination with PCV13.

PEP

PEP must be taken as soon as possible, •but not later than 72 hours after exposure •It must be taken once or twice daily for 28 days PEP is for people without HIV or don't know your HIV status, and in the last 72 hours: •think that may have been exposed to HIV during sex (for example, if the condom broke), •shared needles and works to prepare drugs (for example, cotton, cookers, water), or •were sexually assaulted •It is not 100% effective PEP is also for health-care worker who was accidentally exposed to HIV

Contact dermatitis

PPD test (Mantoux test, Tuberculin test) Exposure to poison ivy; latex, nickel in jewelry; chromium in leather

Periodontal disease

Periodontal disease starts after plaque is formed at gum line. The plaque triggers inflammation reaction Signs & symptoms Stage 1. Gingivitis It is swelling and redness of the gums Within few days of plaque formation §Gums bleed easily §Gums become tender Stage 2. Periodontitis It is progressive loss of bone supporting teeth §Sensitive, swelled, bleeding and receding gums §Bad breath; Teeth become loose and discolored §Loss of bones (seen on X-ray) and teeth Pathogenesis 1.Plaque is formed at gum line and extends into gingival crevice 2.Contact of bacteria with gum triggers inflammation that leads to gingivitis 3.Gingival crevice widens & deepens forming periodontal pockets 4.Bacterial exotoxins are causing bone to soften and recede leading to periodontitis Epidemiology Classification: Hygiene-related disease Reservoir: Humans Routes of transmission: Microbes are part of normal flora Statistics: World-wide data §It is second most common disease §Prevailed in those who are over 35 §90% of elderly have periodontal dis. ‒US data §50% of population is affected §~10% of affected have severe form Risk factors: Stress; Poor oral hygiene; Smoking; Heredity; Crooked teeth; Diabetes; Medications that cause dry mouth Factors increasing the risks of periodontal disease: •Smoking •Diabetes •Poor oral hygiene •Stress •Heredity •Crooked teeth •Underlying immuno-deficiencies •e.g., AIDS •Fillings that became defective •Taking medications that cause dry mouth •Bridges that no longer fit properly •Female hormonal changes, such as with pregnancy or the use of oral contraceptives Prevention To prevent gingivitis: At home §Flossing and brushing everyday To prevent periodontitis: At dental office: §Semi-annual teeth cleaning and polishing Research data: Failing to floss increases the risks of heart diseases and early death - Journal of Aging Research Quality oral health care may inhibit dementia - NIH Record, 2013, LXV, 1. Treatment Treatment of gingivitis and early periodontitis: At dental office: §Plaque removal §Cleaning out inflamed gingival crevice Treatment of advanced periodontitis: At dental office: §Cleaning out inflamed gingival crevices §Minor surgery of affected gums §Antibiotic therapy

Bacterial Infections of Circulatory System

Plague (black death)

PrEP

PrEP is for people without HIV who have had anal or vaginal sex in the past 6 months and: •have a sexual partner with HIV (especially if viral load is unknown or detectable or •have not consistently used a condom or •have been diagnosed with an STD in the past 6 months •Reduces the risk of getting HIV by 99% PrEP is recommended for injected drugs users that: •have an injection partner with HIV or •shares needles, syringes, or other equipment to inject drugs (for example, cookers) •Reduces the risk of getting HIV by about 75% PrEP should be taken by those who has HIV partner and are considering to get pregnant - 99% effective PrEP must be taken daily as long as risky behavior persist. Reasons people stop taking PrEP: •if risk of getting HIV infection becomes low because of changes in life style. •if pills are not taken daily for different reasons •PrEP has side effects •if blood tests show that body is reacting to PrEP in unsafe ways, provider may stop prescribing PrEP for the patient.

Please identify the wound-infecting pathogen shown in the figure.

Pseudomonas aeruginosa

What test further confirmed that the patients were infected with hepatitis C?

RNA sequencing Hepatitis C is an RNA virus, so RNA sequencing was performed to find the correlation between patients who already had hepatitis C and those who contracted it at the dialysis center.

What accounts for a color change in a direct ELISA?

Reaction between enzyme bound to the second antibody and the substrate. The enzyme bound to the secondary antibody hydrolyzes the substrate, which releases a dye.

stages of HIV infection / AIDS

Secondary Immunodeficiency Disorders 1.Incubation period - it can last 2-4 weeks 2.Acute HIV infection - it can last up to 1 month 3. Latency stage - it can last from 2 weeks 4. 4.AIDS - it can last a month or so

What group of viruses does HIV belong to?

Retroviruses HIV, along with HTLV, belongs to the Retrovirus family or Retroviridae.

HIV, and related viruses such as HTLV, possess which unusual virally-encode enzyme?

Reverse transcriptase Reverse transcriptase, an enzyme that makes double-stranded DNA from single-stranded RNA, is characteristic of HIV and other retroviruses.

Strep throat (streptococcal pharyngitis) is caused by

S. pyogenes group A

Hydramacin is unique, but appears to be most similar to proteins found in

Scorpion venom Hydramacin appears to be similar to proteins found in scorpion venom.

Anaerobic Bacterial Infections Tetanus (lockjaw)

Tetanus is caused by a toxin produced by bacterium entered body via deep wound Signs & symptoms Early signs & symptoms •Irritability/difficulty swallowing Contraction of jaw muscles (lockjaw) convulsions Late signs & symptoms •Difficulty in breathing •Rigid arched back (Opisthotonus), leading to stomach's regurgitation Risus sardonicus Opisthotonus •The disease starts with difficulty of swallowing and contraction or spasm of jaw muscles (called lockjaw). •Later it develops into convulsions, difficulties in breathing, Risus sardonicus (rigid smile due to spasm of facial muscles). •In the most severe cases opisthotomis (rigid arched back due to spasm of back muscles) can develop that may lead to regurgitation of stomach resulting secondary infections of lungs (pneumonia). Etiological agent Clostridium tetani •Gram positive obligate anaerobic bacilli that are forming endospores. •Endospores: ‒Have terminal localization; ‒Larger than the cell diameter ‒Extremely resistant to the heat ‒Abundant in dust and soil •Plasmid pE88 encodes two toxins: −Tetanolysin is cholesterol-dependent cytolysin that is released only from dead bacteria. −Tetanospasmin is secretory A-B toxin that is second deadliest biological toxin known (LD50 = 2.5 ng/kg). It blocks signal transduction. •The disease is caused by Clostridium tetani, Gram-positive obligate anaerobic bacillus •It belongs to Firmicutes, the bacterial group with low GC content (24-50%) in DNA. •Under anaerobic condition, microbe forms terminal endospores that are larger than diameter of bacterial cells and are abundant in soil and extremely resistant to heat. •If C. tetani carries pE88 plasmid, it produces two potent exotoxins •Tetanolysin, type II exotoxin that is cholesterol-dependent cytolysin, that cause cell lysis and tissue necrosis. The toxin is released from dead bacterial cells only. •Tetanospasmin, type III exotoxin that is secretory AB toxin. It is second deadliest biological toxin known, LD50 = 2.5 ng/kg of human body. It inhibits signal transduction in nervous system. Pathogenesis •Endospores enter via skin wound •Under anaerobic condition, endospores germinate and C. tetani starts growing •If microbe carries pE88 plasmid, it makes ‒Tetanolysin and Tetanospasmin •Tetanospasmin acts as zinc-dependent protease that stops the vesicle-associated membrane transport between neurons, ‒It blocks release of GABA nd interrupts signal transduction between motor neuron and relaxing neuron leading to muscle spasm, paralysis, and death (in 60% of tetanus cases) •Endospores enter via damaged skin. •They germinate only in anaerobic condition, so the wound can be insect bite, deep puncture, soiled incision or unhealed umbilical cord. •Under anaerobic condition, bacteria carrying pE88 plasmid produces two toxins: 1.Tetanolysin is causing cell lysis and tissue necrosis when released from dead bacteria. 2.Tetanospasmin is secretory AB neurotoxin that it blocks release of GABA (γ-aminobutyric acid) between inhibitory and motor neurons resulting in muscle spasm or paralysis. Cardiac failure develops in 60% of tetanus cases, which leads to death. Epidemiology •Classification: ‒Non-communicable, Notifiable disease •Reservoir: ‒Soil; Rusty objects •Routes of transmission: ‒Damaged skin via puncture, insect bite, deep wound ‒Unhealed umbilical stump •Statistics: ‒US data §Total tetanus is ~30 cases annually §Neonatal tetanus is sporadic ‒World-wide data §Total tetanus is ~10,000 cases §Neonatal tetanus is ~3,500 cases •Non-communicable notifiable disease that has soil and dust as natural reservoir. •Microbe enters the body via deep puncture, wound, wasp/bee bite resulting in tetanus or via unhealed umbilical stump leading to neonatal tetanus. •Neonatal tetanus can develop if instrument used to cut umbilical cord was not properly sterilized. •There are about 10,000 tetanus cases reported globally each year, 50% of them are neonatal tetanus. •40% of all neonatal tetanus cases are reported in African region •Another ¼ of all neonatal tetanus cases are reported in Western pacific region •Neonatal tetanus is practically non-existent in Europe or Americans •In the USA, 20 to 50 cases of tetanus are reported annually, none of them are neonatal cases. Prevention •NOTE: Those who have recovered from tetanus will have no active immunity - they still must be immunized •Vaccine ‒Currently it is DTaP that contains Tetanospasmin toxoid §Produced antibodies will neutralize free toxin but will have no effect on pathogen ‒Immunity wanes 10 years after immunization §Boost immunization is required every 10 years §50% of US population has no adequate protection •DTaP vaccine provides protection against tetanus but boost shots must be done every 10 years. •To ensure adequate oxygenation and thus prevent endospore germination, the deep wound must be thoroughly cleaned with all dead tissue and foreign material removed. Treatment •Thorough cleaning of deep wounds ‒To ensure adequate oxygenation level, remove all dead tissue, foreign material •Antibiotic treatment ‒Penicillin and Erythromycin are given to kill the pathogen and prevent new toxin production •Tetanus immune globulin (TIG) treatment ‒TIG is administered immediately if tetanus is just suspected ‒It inactivates toxin circulating in blood •Tetanus immune globulin (TIG) must be immediately administered if tetanus is suspected. It will neutralize unbound tetanospasmin and stop the disease progression. •Antibiotic treatment (penicillin or erythromycin) would kill bacteria, but would have no effect on toxins. •Recovered from tetanus have no immunity.

Please evaluate the test organism's sensitivity to chloramphenicol.

Sensitive The zone of inhibition measured 27 mm for this drug, which is classified as sensitive to this medication.

Which component of blood contains antibodies?

Serum Serum is the liquid remaining after blood plasma has clotted, and it contains antibodies. Refer to chapter 15 for additional information

Varicella (chickenpox)

Signs & Symptoms •Incubation period up to 2 weeks. •Red spots appear on head's back, then spread to torso and turn to vesicular lesions •Lesions disappear in 1-2 weeks •Disease can be reactivated in form of shingles causing the appearance of painful lesions around waist •Varicella has incubation period up to 2 weeks. •First red spots appear on head's back then spread to rest of body. •Spots turn to vesicular lesions that are mainly located on torso. •Vesicles may turn pustules due to secondary bacterial infections. •Secondary bacterial infections are likely •Lesions disappear in 1-2 weeks •or much later in case of secondary infection. •In some cases, disease may be reactivated years after resulting in shingles (Herpes zoster) •Very painful rash around waist caused by reactivated chickenpox virus •It can coincide with vomiting and possible coma, predominantly seen in children 5 to 15. •Possible liver and brain damage with mortality rate around 30% •Evidence suggests that taking aspirin increases risk of complications

Hair follicle infections

Signs & Symptoms It is exogenous skin disease - microbes are entering the skin along the hair shaft Etiological agent Staphylococcus aureus Folliculitis •It is skin condition when a small pustule, bump or pimple formed around hair follicle. •It has white head surrounded by reddish tissue Furuncle (boil) •It is skin condition when bacteria spread from infected follicle in to adjacent tissues. •It is causing localized redness, swelling, tenderness and pus formation. Carbuncle •It is skin infection that develops in area with a thick skin, affects large areas, leads to abscess formation. •Signs are similar to that of boil, but it can be accompanied by fever. •Potentially it can turn in to systemic infection Pathogenesis •Staphylococcus aureus enters hair follicle along the hair shaft •In hair follicle, pathogen binds to epithelial cells causing an inflammation ‒It is followed by accumulation of leukocytes and dead tissue, forming plug & pus. •COMPLICATIONS: −Spread of infection to subcutaneous tissue may lead to large painful abscesses −If microbe enters bloodstream, infections of heart, bones, and brain are possible Epidemiology •Classification: ‒Non-contagious, Non-notifiable Reservoir: Humans, Routes of transmission: ‒Respiratory droplets ‒Direct (Hand shakes) Indirect contacts (Fomites Statistics: 20% of healthy humans are continuously carrying Staphylococcus aureus asymptomatically, Another 60% will be colonized within a year. For this reason, source of staphylococcal infection outbreaks hard or impossible to identify •Classification: ‒Non-contagious, Non-notifiable Prevention −Keep the skin clean and dry Treatment •Antibiotics treatment ‒Penicillin and Vancomycin use against Staphylococcus aureus is complicated due to microbe's wide-spread antibiotic resistance §90% of strains are resistant to penicillin §They are found in 80% of hospitals §There are VISA, VRSA, MRSA strains ‒Polymyxin or Bacitracin §In form of antimicrobial ointments •Hydrogen peroxide treatment −3% solution overpowers all defensive mechanisms of S. aureus and kills it by destroying membranes and proteins −Very cheap and very effective treatment for superficial skin infections •Rubbing alcohol −60% solution kills bacteria by destroying membrane and dehydration −It also helps to keep the skin dry −Very cheap and very effective treatment for superficial skin infections •Surgical draining of furuncles and carbuncles Ubiquitous •It means: •existing or being everywhere at the same time; •constantly encountered •widespread Glossary •MRSA or methicillin resistant Staphylococcus aureus •VRSA or vancomycin resistant S. aureus •It means that increase of antibiotic concentration 3-5 times has no effect on the growth of a microbe •VISA or vancomycin intermediate resistant S. aureus •It means that increase of antibiotic concentration 2-3 time would stop the microbial growth

Acne

Signs & Symptoms It is exogenous skin infection - microbe enters skin via hair shaft and sebum canal Acne vulgaris Affect pores and upper-most layers of the skin Blackheads or whiteheads are formed on the skin Sometimes it is surrounded by reddish area Inflammatory acne Inflammation involves large area of the skin Nodular, cystic acne It involves deep skin layers. Nodules (cysts) filled with pus are formed Etiological agents Cutibacterium (Propionibacterium) acnes •Gram positive •Slender bent bacilli ‒Forms metachromatic granules •Facultative anaerobe •Virulence factors: ‒Tissue degrading enzymes ‒Biofilms; Some are b-hemolytic Staphylococcus aureus •Gram positive •Cocci arranged in clusters ‒Halophile •Facultative anaerobe •Virulence factors: ‒Numerous virulence factors. ‒For details see slide 6 Pathogenesis •Due to increased sebum production, sebum canal become clogged leading to anaerobic condition ‒Sebum production is increased in teenagers during puberty period •In anaerobic environment, C. acne overgrows and produces hydrolytic enzymes ‒These enzymes cause damage to the lining of sebum canal •Due to this damage S. aureus enters in to surrounding tissues ‒Continuous contact of bacteria with human tissues is causing strong inflammation ‒The type of acne is determined by type of C. acne and S. aureus strains involved in infection •COMPLICATIONS: ‒If bacteria enter blood, it can lead to Endocarditis; Septic arthritis; Corneal ulcers Propionibacterium acne •Some of the strains are opportunistic pathogens as they can produce some virulence factors, including hyaluronate lyase •Hyaluronate lyase is an enzyme that degrades hyaluronan, a component of the extracellular matrix of connective tissue in humans. •These strains in anaerobic conditions and in the presence of Staphylococcus aureus can cause Inflammatory (moderate) or Nodular cystic (severe) acne •P. acne occasionally can enter blood stream and cause: •Corneal ulcers (eye infections) •Endocarditis, damaging heart valves •Septic arthritis, affecting the joints •P. acne is also associated with implant-associated infections as it can form biofilm Epidemiology •Reservoirs: ‒Humans, part of normal flora •Routes of transmission: ‒Cutibacterium (Propionibacterium) acnes is part of normal flora ‒The C. acnes count is tremendously increasing just before puberty •Statistics: ‒Up to 85% teens are affected in the USA and world-wide ‒Acne is related to levels of sebum production -Sebum production is depending on hormones produced by the body •Classification: ‒Non-communicable, Non-notifiable Prevention •Good hygiene ‒General skin cleanness Treatment •Treatment of mild forms: -Topical antimicrobials: Hydrogen peroxide; Benzoyl peroxide (gel) -Phototherapy: C. acne is sensitive to 405-420 nm (blue) light •Treatment of severe forms: Surgical draining of cysts (nodules

Lyme disease

Signs & symptoms 1. Early localized infection It starts few days after tick bite Erythema migrans 2. Early disseminated infection •It starts in 2 to 8 weeks post rash, if disease was left un-treated •Influenza-like symptoms •Painful eye movement, •Enlargement of lymph nodes •Fainting •Irregular heart beat •Paralysis of facial muscles, •Emotional instability •Impaired concentration 3. Late persistent infection •It starts begins within 6 months after rash and slowly disappear over the years •Symptoms develop in 60% of untreated cases •Arthritis of the large joints •Chronic nervous system impairment •Early localized infection •S&S start in few days after tick bite when skin rash appears at site of tick bite as small red dot that slowly enlarges forming erythema migrans that can reach up to 15 cm in diameter •Early disseminated infection •S&S appear in 2 to 8 weeks, if disease left untreated, •Then it is followed by enlargement of lymph nodes •Influenza-like symptoms (malaise, chills, fever, headache, stiff neck, joint and muscle pain, backache). •Fainting and irregular heartbeat as heart's electric conduction become impaired •Paralysis of facial muscles, emotional instability and impaired concentration. •Late persistent infection •S&S appear 6 month after the rash in 60% of untreated cases •Arthritis of large joints (knee, elbow) •Chronic nervous system impairment •Nerve pain, •Numbness or tingling in hands and feet, •Problems with short-term memory, •Inflammation of the brain and spinal cord Possible paralysis and depression Etiological agent Borrelia burgdorferi Gram negative (diderm) Up to 25 mm-long spirochete Microbe has multiple copies of linear genome It has axial filament composed of 11 endoflagella Microaerophilic •Lyme disease is caused by Borrelia burgdorferi, •It is microaerophilic spirochete that is up to 25 micrometers long and has multi-copied linear genome. •It is slow growing with generation time 24-48 hours. •It is considered to be diderm (has double membrane) rather than Gram-negative as it has axial filament composed of 11 endoflagella located between the membranes. •Rotation of axial filament provides the mechanism for screw-in motility of the bacterium. •It is one of the few bacteria that can grow without iron. Pathogenesis •Borrelia burgdorferi enters the host ‒via bite of infected tick ‒Immune response is suppressed by tick saliva at bite site •The growing spirochetes move from the bite site to surrounding tissues ‒It results in local inflammation that appear as enlarging skin rash (erythema migrans) •Borrelia burgdorferi enters bloodstream and cause very intense immune response ‒It causes S & S of early disseminated infection & late persistent infection ‒Pathogen stops growing and, as a result of this, no longer responds to antibiotics •Complications: ‒Autoimmune diseases (Rheumatoid arthritis); Chronic nervous system impairment •Microbe enters the skin via infected tick bite. •Immune response is initially suppressed by tick's saliva, which allows bacteria to growth at the site of bite. •Continued bacterial growth and migration from the bite site are causing the signs of early localized infection - expanding skin rash (erythema migrans) due to inflammation reaction. •After entering the bloodstream, pathogen spreads in the body causing intense immune response resulting in signs and symptoms of early disseminated infection and late persistent infection. •Over the time autoimmune disease may develop. •The pathogen does not cross the placenta. Epidemiology •Classification: ‒Communicable, Notifiable zoonosis •Statistics (continued): ‒US data - up to 30,000 cases annually §Reported in 47 states; Highest rate in PA, NJ, & NY §Most cases are reported in June and July: •Reservoir: ‒White-footed mouse; •Routes of transmission: ‒Bite by infected black-legged tick •Statistics: ‒World-wide data §Disease has spread from the USA to entire world •Communicable, notifiable zoonic disease •Transmitted via bite of infected tick. Several species are involved but the most frequent is black-legged tick (Ixodes scapularis). •Reservoir is the population of white-footed mouse. •Disease is spread to all continents but it is originated in North America. •In 2015, over 28000 cases were reported in the USA in all states but Hawaii, Montana, Oklahoma •95% of them were reported in the North-East and upper Midwest USA, •Pennsylvania, New Jersey and New York accounting the 1stm 2nd, and 3rd highest number of reported cases. •Most of the cases are occurring in June and July. Prevention •Preventing tick bites -Avoid areas w/ tall grass visited by deer -Use repellents containing DEET -Wear protective clothes - light colored secured shirts with long sleeves, pants -Carefully inspect the body & belongings upon leaving tick-infested area •After being bitten by tick -Remove attached ticks without crushing -Submit the tick for analysis. §If tick is infected, you must take antibiotic prophylaxis Treatment •No delays! ‒Seek medical help if bitten by tick or erythema migrans has appeared •Antibiotic treatment -In early (1st) stage of the disease - Doxycycline, Amoxicillin taken orally, recovery rapid and complete §Recovery is rapid and complete. -In advanced (2nd, 3rd) stage of disease - intravenous Ceftriaxone, Ampicillin may be required -Antibiotics are far less effective in these stages of the disease.

Common cold

Signs & symptoms AT THE VERY BEGINNING Scratchy mild sore throat, Cough, Sneezing THEN: Runny nose Initially, nasal secretions are profuse and watery Later, nasal secretions turn thick, purulent (pus-like) No fever, unless secondary infection is present Signs and symptoms disappear in about a week Etiological agent Disease is caused by various rhinoviruses Rhinoviruses are Small non-enveloped viruses Genome is single-stranded RNA This is a basis for high mutation rate and antigenic drift More than 100 known serotypes of rhinoviruses As a result, there is no vaccine available High mutation rate in RNA viruses •It is due to inability of RNA polymerase, enzyme required for replication of RNA viruses, has no ability to do a proof-reading of replicated RNA molecule •Unlike to RNA polymerase, DNA polymerase has ability to do proofreading - if during chromosome replication a wrong nucleotide is inserted in growing strand of DNA, the enzyme (DNA polymerase) can recognize a mistake, remove wrong nucleotide and replace it with a correct one. •Continuous mutation of nucleotides in genes of RNA viruses is resulting in continuous change of antigenic properties of viral proteins, called antigenic drift. Pathogenesis Virus binds to epithelial cells of mucous membrane in pharynx. Virus enters the cell and replicates via lytic cycle Infected and killed cells and newly produced viral particles are causing the inflammation reaction It sets off the signs and symptoms Infection is halted by antibody produced during immune response mounted by host organism COMPLICATIONS: Primary viral infection may extend to §ears, §sinuses §lower respiratory tract (pneumonia) Secondary viral or bacterial infections (pneumonia) Epidemiology Classification: Contagious, Non-Notifiable disease Zoonosis ??? Reservoir: Humans only Routes of transmission: −Respiratory droplets; −Direct contacts (hand shake); −Indirect contacts (fomites); −High viral load is in nasal secretions particularly during first 3 days of disease Young children are easily transmitting disease due to lack of good hygiene Statistics: Not Available. Prevention •Quarantine ‒For those who are infected Vaccine NONE. Too many viruses and their different serotypes are causing common cold Good hygiene Frequent hand washing Avoiding crowds during times when common cold is prevalent Keeping hands away from face Treatment Antibiotic treatment Antibiotics are ineffectual (USELESS) More over, they may prolong duration of infection due to inhibition of inflammation Antiviral drugs They may reduce the spread of the disease if taken at onset of symptoms

Tuberculosis

Signs & symptoms Chronic illness that starts with Loss of appetite & Fatigue Followed by Chest pain Slight fever with night sweats Progressive weight loss Chronic productive cough If sputum contains blood, tuberculosis turns to active form and individual becomes infective to others Etiological agent Mycobacterium tuberculosis and other related mycobacterial species (see slide notes) Slender, acid fast aerobic bacilli It is slow growing (generation time ~ 20 hours) and resistant to antibiotic treatment and disinfectants due to hydrophobic cell wall, Easy killed by pasteurization procedure. It grows in characteristic cell clusters, It is called "corded growth" Virulence factor: Components of cell wall Microbe does not produce any known toxins •The disease is caused primarily by Mycobacterium tuberculosis. •However other mycobacterial species can also cause tuberculosis in humans: •M. africanum (limited to Africa); M. bovis (threat from this species was eliminated with introduction of milk pasteurization); M. canetti (limited to Africa); M. microtti (found largely in HIV-infected patients); •Mycobacterial species belong to phylum Actinobacteria, which is a group of Gram positive bacteria with high content of G/C (69-73%) in their DNA. •They have hydrophobic acid-fast cell wall that is very hydrophobic and contains compounds that enable bacterial survival inside macrophages by inhibiting digestion. •As a result, mycobacteria have very long generation time - from 24 hours to 12 days. •Bacteria are aerobic slender bacilli that do not form endospores and show corded growth in culture, when the cells are sticking to each other due to high hydrophobicity of cell wall. •Virulence factors •Mycobacteria produce no known toxins •The only known virulence factor - components of cell wall that enable bacteria to survive and grow inside macrophages Mycobacterial species causing diseases other than tuberculosis •Mycobacterium leprae - causes leprosy or Hansen's disease •Mycobacterium marinum - may be occupational hazard to pet shop workers as it was isolated from fish and causes skin lesions •Mycobacterium avium - causes atypical mycobacterial infections in patients with late stages of HIV infection •Mycobacterium kansasii - cause chronic human pulmonary disease resembling tuberculosis and skin infections Pathogenesis •Damage is due to delayed cell-mediated hypersensitivity reaction (type IV allergy). Tubercles are clearly seen on X-ray images as multiple whitish dots Matured tubercle brakes up letting microbe into airways. Active form of TB develops •Damage to infected is done due to type IV delayed allergy reaction. •After entering alveola, pathogen is ingested by alveolar macrophage. •Due to acid-fast cell wall, microbe survives inside macrophage and replicate, forming primary site of infection. •New macrophages are attracted to this site trying to kill pathogen and infected macrophage, which leads to new macrophages becoming infected. •Since the infection cannot be eliminated, a protective wall (granuloma known as tubercule) is eventually formed, separating the site of infection from the rest of host. •At this point infection is in inactive form and person is not infective to others. •Formation of tubercle results in chronic inflammation reaction that leads to slow maturation of tubercle and their calcification. •At this point first signs and symptoms would appear. •NOTE: 90% of TB cases are asymptomatic •If mature tubercle breaks up, it leads to appearance of blood in sputum and appearance of bacterial cells in respiratory airways. •At this point tuberculosis turns to active form and person becomes highly infective to others. •Microbe enters lymphatic system and is spread to other parts of the body forming secondary sites of infection (i.e. in the bones). •If disease at this stage is left untreated, mortality rate is almost 100%. •Latent tuberculosis infections may turn into tuberculosis (disease), if the person's immune system is impaired by stress, advanced age, or disease like AIDS Epidemiology Reservoir: Humans; Animals Routes of transmission: ‒Respiratory droplets (ID50 = 10), ‒Direct contacts (hand shakes) ‒Indirect contacts (fomites) Disease can also be contracted from animals (via raw cow milk) •Classification: ‒Contagious(*), Notifiable disease •Statistics: ‒World-wide data - over 6,000,000 cases annually. On increase ‒US data - about 9,000 cases annually. Decreasing Transmission rate is increased by Lack of ventilation; Coughing; Crowded quarters HIV infection increases risk of tuberculosis •Statistics: ‒World-wide data - over 6,000,000 cases annually. On increase ‒US data - about 9,000 cases annually. Decreasing Transmission rate is increased by Lack of ventilation; Coughing; Crowded quarters HIV infection increases risk of tuberculosis Statistical data: •Tuberculosis cases reported world-wide had increased from about 3 million in 1993 to about 6 million in 2010 and continue to increase. •During same period the number of cases reported in the USA had dropped from 25,000 to about 11,000 and continue to drop. •TB cases are approximately evenly distributed among Whites, Hispanics, and Asians at about 3,600 in each group. Number of TB cases in Blacks are over 5,100. Tuberculosis Trends — United States, 2014 - MMWR, March 20, 2015 / 64(10);265-269 - https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6410a2.htm •In 2014, a total of 9,412 new tuberculosis (TB) cases were reported in the United States, with an incidence rate of 3.0* cases per 100,000 persons, a decrease of 2.2% from 2013 (1). The percentage decrease in rate is the smallest decrease in over a decade. Tuberculosis — United States, 1993-2010 - MMWR, November 22, 2013 / 62(03);149-154 - https://www.cdc.gov/mmwr/preview/mmwrhtml/su6203a25.htm •Tuberculosis (TB) is transmitted via the airborne route by person-to-person contact. •Although TB is a leading cause of death on a global scale, most cases can be cured with treatment. •From 1993 to 2010, the TB cases reported in the US decreased from 25,103 to 11,182. •Despite the decrease, TB continues to affect many communities in the United States disproportionately and unequally, especially racial/ethnic minorities and foreign-born persons. •TB remains one of many diseases and health conditions with large disparities and inequalities by income, race/ethnicity, educational attainment, and other sociodemographic characteristics. Prevention •Quarantine ‒For those who have active form TB •Screening of general public ‒Tuberculin test (Montoux, PPD) is used to detect those who were previously exposed to pathogen - see slide's notes for details ‒Chest X-ray is required for confirmation of tuberculosis Vaccine BCG vaccine is used to immunize general public in Europe In the USA, this vaccine is reserved to individuals with high-risk, like Health-care workers, School teachers It is not used for general public on the grounds that it eliminates the use of PPD. Treatment Antibiotic treatment It is based on use of antibiotic cocktails 1)Antibiotics that reduce hydrophobicity of cell wall of acid-fast pathogen ‒Pyrazinamide inhibits fatty acid synthesis; Isoniazid inhibits mycolic acid synthesis; ‒Ethambutol prevents attachment of mycolic acids to cell wall; 2)Bactericidal antibiotics that kill acid-fast pathogen ‒Streptomycin inhibits protein synthesis; ‒Rifampin inhibits RNA synthesis; Ciprofloxacin inhibits DNA synthesis •Since the antibiotic treatment lasts few months, Directly Observed Therapy (DOT) is used during initial treatment of tuberculosis (see slide 23 of lecture 8) •It requires the use of antibiotic cocktail for several months. •As a result, DOTS (directly observed therapy short course) is mandatory at the beginning of treatment to ensure that no doses are missed. •Antibiotic cocktail includes drugs that reduce hydrophobicity of mycobacterial cell wall (Ethambutol, Isoniazid, Pyrazinamide) combined with bactericidal antibiotics inhibiting nucleic acid synthesis (Rifampin) or protein synthesis (Streptomycin). Diagnostics (Tuberculin or Montoux or PPD test), •A standard dose of tuberculin antigen injected intradermally. •Reaction is read in 48-72 hours by measuring the diameter of induration (raised hardened area). •If no induration or if it is less than 5 mm, the result is negative. Erythema is not measured. •Positive result indicates that person was exposed to mycobacteria. •X-ray of chest must be taken for positive confirmation of tuberculosis.

Dental caries (tooth decay)

Signs & symptoms Disease develops before signs become apparent Once developed, symptoms include: Discoloration of a tooth Roughness or defect in a tooth Pain, Swollen gums Tooth can break while chewing Etiological agent Streptococcus mutans Gram-positive Cocci arranged in chains Facultative anaerobe. −It is part of normal flora Virulence factors: −In sucrose presence, it forms biofilm - tooth plaque −Produces a lot of lactic acid during fructose fermentation Pathogenesis Using adhesins, Streptococcus mutans binds to surface of the teeth enamel In the presence of dietary sucrose, S. mutans produces glucans, forms biofilm known as dental plaque While fermenting fructose (comes from sucrose) microbe produces lactic acid retained in plaque. In acidic pH, calcium is dissolved, washed out from enamel leading to dental caries At advanced stages of caries development, other bacteria also play role Epidemiology Classification: Hygiene-related disease Routes of transmission: Microbe is part of normal flora Statistics: It is the most common disease in humans Risk factors: Diet - disease's incidence is depending mainly on availability of sucrose §does breast over-feeding lead to early caries? Environmental factors - excessive iron in water increases the rate of the disease Heredity & Income - microbial binding is receptor-specific, dental care reduces risks Age - young people are more susceptible to disease than adults Reservoir: Humans

Shigellosis

Signs & symptoms Incubation period from 12 hours to 4 days Disease starts with Stomach cramps; Nausea; Vomiting Mucoid diarrhea In severe cases, infected develops: Fever; Bloody diarrhea; Signs and symptoms last for up to 7 days Severity of S&S is determined by microbial species and pathogen's strain Etiological agents Shigella dysenteriae, S. flexneri •Virulence factors: ‒High resistance to stomach acid ‒Type III secretion system ‒Effector proteins ‒Endotoxin (heat-resistant LPS) ‒Variety of exotoxins •Gram-negative •Bacilli (enteric bacteria) •Facultative anaerobe •Non-motile outside of the host cell ‒Inside host it uses actin-based motility ‒Some strains may form flagella Pathogenesis Ingested Shigella passes stomach and enters the guts It is taken up by M cells during antigen sampling and presented to macrophage that ingests it Ingested microbe avoids digestion & escapes macrophage after killing it by exotoxin. Using adhesins, Shigella binds to epithelial cells Effectors proteins injected by the bacteria via type III secretion system, are forcing epithelial cells to take up Shigella via directed uptake mechanism (see lecture 8) Inside epithelial cells Shigella becomes motile by producing actin tails It allows bacteria to spread from one cell to another Produced exotoxins and inflammation are killing off infected cells Complications: Seizures; Post-infectious arthritis •Bacteria are up taken by M cells of the large intestine in "antigen sampling" •M cells transport bacterium beneath epithelium and present it to macrophage •After evasion of macrophage digestion, Shigella adhere to epithelial cells and using type III secretion system enters into epithelial cells via "directed uptake" •Bacteria multiply at high rate inside epithelial cells and moving about via "polymerized actin tails". These tails push bacteria from one cell into another •Dead cells slough off initiating intense inflammatory response •The areas covered with pus and blood appear in the intestines leading to appearance of the blood in the feces •Some strains of S. dysenteriae produce potent A-B toxin - Shiga toxin that associated with fatal hemolytic uremic syndrome •A treatment given to counteract the effect of shiga toxin would also decrease the severity of infections caused by E. coli O157:H7. Epidemiology Classification: Contagious, Notifiable disease Reservoir: Humans, Apes Routes of transmission: Oral-Fecal route, ID50 = 10 −Contaminated food and water (vehicles) −Direct (hand shake); −Indirect contacts (fomites); Statistics: World-wide data §Estimated over 80,000,000 cases annually §Estimated up to 1,000,000 deaths annually The US data §About 15,000 reported cases. §Number of cases are declining ‒Transmission is more likely when hygiene and sanitation standards are poor •Shigella is the third most common cause of travelers' diarrhea in patients returning to the USA •Risk of infection is highest for people traveling to Africa, followed by Central America, South America, and Asia. •Fomites are objects or materials that are likely to carry infection, such as clothes, utensils, and furniture Prevention Vaccine NONE, due to high antigenic variability of Shigella. Over 50 known serotypes. Good hygiene Thorough & frequent hand washing •Water supply ‒Securing water source ‒Water disinfection •Food supply ‒Surveillance of food handlers & supplies Travelers Good hygiene - Frequent hand washing before cooking and eating; Safe food and water - §Avoid street food vendors; §Cook the food immediately before eating; Fruit must be peeled personally; §Use boiled or bottled water; Avoid ice unless it is made of boiled water; Treatment Usually, shigellosis will resolve within 4-7 days, even without treatment •Rehydration ‒Fluids and electrolytes §Administered orally §In severe cases - intravenously ‒Zinc treatment §It reduces stool volume by 10% and shortens diarrhea by 8 h •Antibiotic treatment ‒Broad-spectrum antibiotics like Cephalosporin, Ciprofloxacin ‒>20% of Shigella strains are resistant to antibiotics due to R plasmid. ‒Some strains are multi drug resistant Diagnostics •Disease is confirmed by culture of stool specimen or rectal swab •Samples must be processed quickly as microbe can not survive for long outside of the host

Pertussis (whooping cough)

Signs & symptoms Incubation period up to 14 days 1.Catarrhal stage S&S are similar to that of common cold 2.Paroxysmal stage Severe cough spasms followed by a forceful air inspiration. Fever, Vomiting, Seizure may occur 3.Convalescence stage Recovery from disease Etiological agent Bordetella pertussis Gram negative, Coccobacillus, Obligate aerobe Outside the host, it survives for short periods only Virulence factors: Capsule Endotoxin Various exotoxins §Pertussis toxin; §Filamentous hemagglutinin; §Invasive adenylate cyclase; §Tracheal cytotoxin Virulence factors of Bordetella pertussis •Capsule - interferes with phagocytosis, blocking the binding of phagocytic cells to a microbe •Toxins: •Pertussis toxin (PTx) - it is adhesin that participates in attachment of a microbe to the host cell. •It is also A-B toxin. A-subunit as it enters cytoplasm of targeted cells activates membrane-bound regulatory protein which leads to increased production of cAMP, •It in turn increases mucus production, decreased killing ability of phagocytes and natural killers •Invasive adenylate cyclase - it is both membrane-damaging toxin and enzyme. •It is causing lysis of accumulated leukocytes and •It is increasing the intracellular level of cyclic AMP •inhibiting the function of T-helper cells •Tracheal cytotoxin - interferes with functions of ciliated cells, causing ciliostasis and killing off the ciliated cells. It also induces fever- •Filamentous hemagglutinin - is involved in microbial attachment to the host cell Pathogenesis Pathogen enters respiratory tract with droplets It attaches to ciliated cells using pertussis toxin (PTx) and filamentous hemagglutinin (FHA) as adhesins Microbe colonizes mucous membranes of Nasopharynx; Trachea; Bronchi; Bronchioles Microbe grows in dense masses producing various toxins: −Pertussis toxin (PTx) is also increasing mucus production via increased cAMP synthesis −Invasive adenylate cyclase is membrane-damaging toxin and enzyme: it is causing the lysis of leukocytes and further increasing mucus production −Tracheal cytotoxin is causing ciliostasis (ciliated cells stop beating) and death of ciliated cells §It is also pyrogenic (causing fever) Combination of increased mucus production and massive death of ciliated cells results in Whooping Cough Reflex as some bronchioles become completely obstructed by mucus Complications: −Secondary infections (pneumonia) are common; Seizures; Encephalopathy •Using pertussis toxin and filamentous hemagglutinin as adhesins, B. pertussis attaches to ciliated cells and colonizes nasopharynx trachea, bronchi and bronchioles. •Pertussis toxin and invasive adenylate cyclase (IAC) dramatically increase mucous production. •At the same time, IAC kills off leucocytes and tracheal cytotoxin is causing ciliostasis and kills off ciliated cells. •Resulting mucous buildup triggers whooping cough reflex. Pneumonia caused by secondary infections is the most common complication. •Presence of Bordetella and toxin production leads to inflammation reaction and cough reflex to clear excessive secretions. Spasmatic cough may last up to 6 weeks •Possible complications •Pneumonia (often) •Seizures, •Encephalopathy, Epidemiology •Classification: ‒Contagious, Notifiable disease Reservoir: Humans only Routes of transmission: Respiratory droplets Direct contacts Indirect contacts Statistics: World-wide data - about 100,000 cases annually, in decline Over 50% of cases occur in infants. It is often mistaken for persistent common cold US data - >10,000 cases annually, increasing Epidemiology: •It is highly contagious, notifiable disease. Natural reservoir is humans only. Disease is transmitted by respiratory droplets, direct and indirect contacts. Most of the reported cases occur in infants. •Due to herd immunity, number of cases reported globally has dropped from about 2 million cases in 1980 to about 78,000 cases in 2009 and continue to decrease. •However, the number of the cases reported in the USA has increased from 1,700 cases reported in 1980 to 12,000 cases reported in 2009. Pertussis Epidemic — California, 2014 - MMWR, December 5, 2014 / 63(48);1129-1132 - https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6348a2.htm •On June 13, 2014, the California Department of Public Health (CDPH) declared that a pertussis epidemic was occurring in the state when reported incidence was more than five times greater than baseline levels. Pertussis Epidemic — Washington, 2012 - MMWR, July 20, 2012 / 61(28);517-522 - https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6128a1.htm •Since mid-2011, a substantial rise in pertussis cases has been reported in the state of Washington. •In response to this increase, the Washington State Secretary of Health declared a pertussis epidemic on April 3, 2012. •By June 16, the reported number of cases in Washington in 2012 had reached 2,520 (37.5 cases per 100,000 residents), a 1,300% increase compared with the same period in 2011. Outbreaks of Pertussis Associated with Hospitals --- Kentucky, Pennsylvania, and Oregon, 2003 - MMWR , January 28, 2005 / 54(03);67-71 - https://www.cdc.gov/mmwr/preview/mmwrhtml/mm5403a3.htm •Pertussis outbreaks have been reported in various settings, including sports facilities, summer camps, schools, and health-care facilities. •Mild and atypical manifestations of pertussis among infected persons and the lack of quick and accurate diagnostic tests can make pertussis outbreaks difficult to recognize and therefore difficult to control. •Outbreaks among health-care workers (HCWs) are of special concern because of the risk for transmission to vulnerable patients. •This report describes three pertussis outbreaks among HCWs and patients that occurred in hospitals in Kentucky, Pennsylvania, and Oregon in 2003. Prevention •Quarantine ‒Up to 6 weeks for those who are infected Antibiotics prophylaxis Erythromycin may be used for those who were in contact with infected Vaccine Currently it is DTaP that contains acellular Pertussis §Immunity wanes 10 years after immunization §Boost immunization is required Vaccine is 70% effective •Quarantine •For up to 6 weeks to prevent spread of the disease. •Antibiotics prophylaxis •Antibiotics are prescribed to anyone who was in contact with infected person to kill bacteria and prevent spreading of the disease. •DTaP vaccine •It is a part of the US immunization schedule. •It includes acellular component of pertussis (toxoid) that triggers production of protective antibodies (70% effective). •Booster immunization is required every 10 years. •There is 85% coverage with 3rd dose of vaccine among 1-year-olds world-wide (over 95% coverage in the USA). About 50% of adult •population in the USA does not have proper protection against pertussis. Treatment Antibiotic treatment Erythromycin or Sulfa drugs are effective during catarrhal stage Antibiotics are not effective during paroxysmal stage - WHY •Antibiotics are effective only during catarrhal stage of disease. •Erythromycin or sulfa drugs are antibiotics of choice. •During paroxysmal stage of disease antibiotics are not effective.

Necrotizing fasciitis (flesh eating disease)

Signs & symptoms Infection begins at site of trauma Sites of surgery Skin bruises Insect bites, Tissues become red and swollen within hours Necrosis of the subcutaneous tissues Skin color turns violet Intense pain & Fever Diarrhea and vomiting Etiological agents Gram-positive cocci: −Streptococcus pyogenes (most cases) −Staphylococcus aureus Gram-positive bacilli: Clostridium perfringens §For properties, see slide noted Clostridium perfringens •Gram-positive •endospore-forming bacillus •Obligate anaerobe •Virulence factors: •Perfringolysin, a-toxin - both are membrane-damaging toxins •Vigorous fermenters that produce a lot of gases that increase invasiveness •It may cause annually as much as 250,000 cases of foodborne diseases in the USA Pathogenesis •Infection leads to rapid human tissue necrosis •Mortality rate is up to 25% •Pathogens produce various virulence factors that increase microbial invasiveness Staphylococcus aureus Proteases •Enzymes digesting proteins Superantigen •Nonspecific activation of T cells resulting in cytokine storm Leukocidins •Membrane-damaging exotoxins a, b toxins •Membrane-damaging exotoxins Streptococcus pyogenes Proteases •Enzymes digesting proteins Superantigen •Nonspecific activation of T cells resulting in cytokine storm Streptolysin O •Exotoxin that forms pores in cholesterol-rich membranes Streptolysin S •Exotoxin that forms pores in cholesterol-rich membranes Clostridium perfringens Proteases •Enzymes digesting proteins Perfringolysin O •Exotoxin that forms pores in cholesterol-rich membranes a toxin •Membrane-damaging exotoxin Hydrogen & Carbon dioxide •Gases produced in huge quantities during bacterial growth •Produced exotoxins are secreted by bacteria and are killing the cells at infection site causing necrosis of tissue. •Invasive strains of S. pyogenes produce both pyrogenic exotoxin A and pyrogenic exotoxin B Epidemiology •Classification: ‒Communicable, Notifiable disease, often nosocomial •Reservoir: ‒Infected humans ‒Environment •Routes of transmission: ‒Vehicles (Parenteral route) §Enters via skin breaks •Statistics: ‒US data - ~1,500 cases; §Mortality rate can reach 60% if disease coincides with streptococcal toxic shock syndrome •Risk factors: Immunocompromised; Diabetes mellitus; Elderly •Healthy individual who has a strong immune system, and practices good hygiene and proper wound care, has extremely low chances of getting necrotizing fasciitis ("flesh-eating" bacteria). •Most people who get necrotizing fasciitis have other health problems that may lower their body's ability to fight infection. •Some of these conditions include diabetes, kidney disease, cancer, or other chronic health conditions that weaken the body's immune system. Prevention •Antibiotic prophylaxis ‒Usually it is not recommended for those who were in contact with infected •Vaccine ‒NONE •Good hygiene ‒Keep skin clean ‒Prompt wound treatment Treatment •Surgery −Early removal of necrotic tissue −In advanced stages - Limb amputation, Skin grafts •Antibiotic treatment ‒Broad-spectrum antibiotics (Vancomycin, Erythromycin) administered parenterally •Hyperbaric oxygen treatment ‒It is effective only for infections caused by Clostridium perfringens - WHY? •The first line of defense against this disease is strong antibiotics given parenterally. But since bacterial toxins can destroy soft tissue and reduce blood flow, antibiotics may not reach all of the infected and dying areas. This is why rapid surgical exploration and removal of dead tissue—in addition to antibiotics—is often critical to stopping the infection.

Helicobacter pylori gastritis

Signs & symptoms Most cases are asymptomatic S&S develop if stomach infection is advanced and is complicated by ulcer / cancer (20% or 2% of cases, respectively): Bloating; Belching, Bleeding; Abdominal pain; Vomiting; •Most of the cases are asymptomatic. •S&S are developing when stomach infection is already in advanced stage and it is complicated by stomach or duodenum ulcers (20% of infections) or/and stomach cancer (develops in 2% of cases). •Symptoms of advanced infection include: •Belching (noisy gas emission from stomach through the mouth), •Bloating (swollen state of stomach caused by retention of gas) •Bleeding, Abdominal pain Etiological agent Helicobacter pylori Gram negative, Motile (lophotrichous), short, curved bacilli Microaerophilic and Alkalophilic Virulence factors: Urease (coverts urea to ammonia), LPS and various Exotoxins •The disease is caused by Helicobacter pylori •It is Gram-negative, microaerophilic, alkaliphilic (optimal pH 8), mobile (lophotrichous) short curved bacillus that belong to epsilon-proteobacteria. •The microbe is fastidious, requiring blood, and slow growing - colonies are forming within 2-4 days. •Virulence factors include •urease (produces ammonia), •LPS similar to the host mucus, •various exotoxins (phospholipases, cytotoxins VacA and CagA). Pathogenesis Infection leads to inflammation resulting in exposure of stomach lining to acid & development of ulcer •Ingested pathogen enters mucous and binds to stomach lining. •Bacterial urease forms ammonia that neutralizes pH locally and disturbs tight junctions between the cells of stomach lining. •Bacterial LPS that is similar to host mucus reduces the phagocytosis and inflammation reaction. •Bacterial proteases and VacA cytotoxin cause damage membrane of the host cell, which leads to cell death. •Reduced mucus production exposes the lining to acid leading to formation of ulcers. •Strains linked to cancer are also producing CagA toxin that is delivered via Type III secretion system. Cancer in Helicobacter pylori infection •Strains of H. pylori associated with increased risk of cancer produce CagA cytotoxin •The toxin is delivered to host cells via type III secretion system •It interferes with host cell signaling and promoting inflammation •Only ~2% of chronically infected develop cancer. •It is thought that not microbe itself but exposure of host cells to acid and forced continuous cell division to replenish lost stomach lining is causing cancer due to mutations. Epidemiology •Classification: Communicable (Contagious?), non-Notifiable disease Statistics: World-wide data §70% of population is infected in developing countries US data §Up to 40% of the US population is infected §Incidence is higher in lower socio-economic groups §Infections tend to cluster in families §Incidence rate is in direct correlation with the age Reservoirs: Infected humans Routes of transmission: Fecal-Oral & Oral-Oral Contaminated food (vehicle) Houseflies (vectors) Prevention •No proven preventive measures ‒Generally good hygiene? Diagnostics Fecal antigen assay; Urea breath test; Biopsy §Histology §Rapid urease test •Lactobacillus casei strain Shirota ‒It has been shown that strain Shirota inhibit the growth of H. pylori "in vitro" Treatment Antibiotic treatment Mix of two broad-spectrum antibiotics (Erythromycin, Clarithromycin, Amoxicillin) and Antacid taken rally for 2 weeks

Cholera

Signs & symptoms Most of the cases are asymptomatic or have mild S&S 5-10% of cholera cases are severe and have the following S&S: In early stages of infection §Vomiting §Rapid heart rate ‒In advanced stages of cholera §Profuse watery diarrhea or "rice-water stool" oInfected will loose up to 20 liters of fluids oRice-water stool would contain up to 100,000,000 bacteria per 1 ml §Dry mouth; Thirst; Loss of skin elasticity; Muscle cramps; Low blood pressure; §Restlessness; Irritability §If left untreated, severe dehydration & electrolyte imbalance would quickly lead to shock and death •from 5% to 10% of infections develop vomiting and profuse watery diarrhea (called rice-water stool) that leads to loss of up to 20 liters of fluids a day with up to 108 bacterial cells per 1 ml. •As a result, patient experiences thirst, dry mucous membrane, loss of skin elasticity, muscle cramps, low blood pressure. •If severe cases left untreated, patient dies due to severe dehydration and electrolyte imbalance. Etiological agent Vibrio cholerae Sensitive to acidic pH; but tolerant to salt & alkaline pH Virulence factor: Cholera toxin (AB) is produced, if bacteria lysogenic for CTXj virus Gram negative Motile vibrio (curved bacillus) with single flagellum Facultative anaerobe •Disease is caused by Vibrio cholerae that is non-enteric bacterium of class g-Proteobacteria. •It is Gram-negative facultative anaerobic curved bacillus (vibrio) with single flagellum. It is sensitive to acidic pH but tolerate elevated salt and pH p to 9.5. Therefore, it can survive in brackish waters. •To cause infection, bacterium must be lysogenic for CTXj filamentous virus. Lysogenic bacteria produce cholera toxin, that is type III intracellular A-B exotoxin. Pathogenesis Only Vibrio cholerae lysogenic for CTXj virus can produce cholera toxin Most of ingested V. cholerae are killed by stomach acid That is why the pathogen's ID50 = 100 x 106 cells, but the use of antacid lowers it to 0.01 x 106 cells In the guts, surviving bacteria use pili-located adhesins to bind to epithelial cells Produced cholera toxin enters epithelial cells & up-regulates adenylate cyclase Increased level of cAMP results in massive loss of chlorine ions In turn, large amount of water leaves the affected cells due to created osmosis resulting in diarrhea Infected person may lose up to 20 liters of fluids. For comparison: total volume of blood in average human is about 5 liters •V. cholerae is pathogenic when it is lysogenic for CTXj virus. •Upon colonization of the guts, V. cholerae lysogenic for CTXj virus produces cholera toxin that enters epithelial cell and up-regulates the adenylate cyclase activity. •Increased level of cAMP causes epithelial cells to secrete large amount of chlorine ions. •In turn, large amount of water leaves the affected cells due to osmosis, which is resulting in highly characteristic for this infection "rice water" stool. •Infected person may lose up to 20 liters of fluids. •In severe cases infected may even die if infection is not treated. Epidemiology Classification: Communicable, Notifiable disease •Reservoir: ‒Brackish water, ‒Plankton, ‒Crabs, ‒Shellfish •Routes of transmission: ‒Fecal-Oral route via contaminated water, seafood or produce grown with human feces as fertilizer. •Statistics: ‒World-wide data - about 150,000 cases annually. On increase. §Serious outbreaks occur if infrastructure affected by war, earthquake or hurricane §Haiti cholera outbreak 2010: oAbout 750,000 cases reported o50% infected were hospitalized oOver 8,600 died (1.2% fatality rate) ‒US data - about 10 cases annually •Cholera is communicable, notifiable disease. •Reservoirs - contaminated brackish waters, plankton, crabs, shellfish, vegetables grown with human feces as fertilizers. •Transmission occurs via fecal-oral route. V. cholerae is acid-sensitive and has ID50 = 108 vibrios. However, if antacid is taken, ID50 is about 104 vibrios. •Over 100,000 cases of cholera reported world-wide annually. •However large outbreaks can occur: over 700,000 cases were reported in Haiti in 2010. •Over 8,600 people have died in this outbreak. Under 10 cases of cholera reported in the USA annually Key facts: •Cholera is an acute diarrheal disease that can kill within hours if left untreated. •Researchers have estimated that each year there are 1.3 million to 4.0 million cases of cholera, and 21 000 to 143 000 deaths worldwide due to cholera. •Up to 80% of cases can be successfully treated with oral rehydration solution (ORS). •Severe cases will need rapid treatment with intravenous fluids and antibiotics. •Provision of safe water and sanitation is critical to control the transmission of cholera and other waterborne diseases. •Safe oral cholera vaccines should be used in conjunction with improvements in water and sanitation to control cholera outbreaks and for prevention in areas known to be high risk for cholera. •A global strategy on cholera control with a target to reduce cholera deaths by 90% was launched in 2017. WHO: Ending Cholera. A Global Roadmap to 2030 •The new global strategy for cholera control at the country level and provides a concrete path toward a world in which cholera is no longer a threat to public health. • By implementing the strategy between now and 2030, the Global Task Force on Cholera Control (GTFCC) partners will support countries to reduce cholera deaths by 90 percent. •With the commitment of cholera-affected countries, technical partners, and donors, as many as 20 countries could eliminate disease transmission by 2030. Prevention •Water supply ‒Securing water source ‒Water disinfection (Chlorination, Ozon- or UV-treatment) •Food supply ‒Adequate sanitary precautions and practices Travelers Vaccine - Oral vaccine against cholera toxin is 85-90% effective for 6 months Good hygiene - Frequent hand washing, especially before cooking and eating; Safe food and water - §Cook the food immediately before eating; Fruit must be peeled personally; §Use boiled or bottled water; Avoid ice unless it is made of boiled water; •Adequate sanitation (hand washing etc.) and safe (chlorinated) water supply. •Oral cholera toxoid vaccine is 90% effective for the next 6 months. It is not on US immunization schedule and is recommended for travelers. •Travelers should maintain good hygiene: frequent hand washing, especially before cooking and eating; avoid ice made of un-boiled water; food cooking just before consumption; peel fruit personally; use only boiled or bottled water, including in dishwashing. Treatment •Antibiotic treatment ‒It is not recommended ‒Antibiotics are quickly excreted from the body due to "rice water" stool and therefore: §It does not limit spread of disease §It will contribute to bacterial resistance to antibiotics. •Rehydration ‒Fluids and electrolytes §Administered orally §In severe cases - intravenously ‒Zinc treatment §It reduces stool volume by 10% and shortens diarrhea by 8 h •Antibiotics treatment usually are not recommended. •Prompt rehydration and electrolyte replenishment. •It has been shown that Zinc treatment significantly reduces stool volume and shorten diarrhea. Zinc treatment •http://www.cdc.gov/cholera/treatment/zinc-treatment.html •A study in Bangladesh showed that zinc supplementation significantly reduced the duration and severity of diarrhea in children suffering from cholera. •The study was conducted with 179 children, 3-14 years old, who were admitted to a hospital within 24 hours of the onset of cholera symptoms. •In the study, all children received antibiotics and rehydration therapy as needed, but those in the intervention group also received zinc supplementation. •Children who received zinc supplementation had 8 fewer hours of diarrheal illness and 10% less diarrheal stool volume, on average. •Zinc has also been shown to have a similar effect in children with diarrhea caused by infections other than cholera, and is recommended for the treatment of pediatric diarrhea more generally.

Diphtheria

Signs & symptoms Onset signs and symptoms (Respiratory form): It begins with mild sore throat that accompanied by slight fever, It is followed by fatigue, malaise, Barking cough Advanced signs and symptoms (Respiratory form): Bull neck - dramatic swelling of the neck, Whitish pseudo-membrane formed on tonsils, pharynx Difficulties in breathing with possible bluish coloration of skin due to low oxygenation level Signs and symptoms of respiratory form of diphtheria •It starts with mild sore throat, slight fever and barking cough. •It is followed by neck swelling known as "bull neck", difficulties in breathing and formation of whitish pseudo-membrane on tonsils and pharynx. •Whitish pseudo-membrane is highly specific sign for diphtheria. It is comprised of dead human cells, bacterial cells and has high concentration of diphtheria toxin Etiological agent Corynebacterium diphtheriae - see slide notes Non-invasive bacterium producing 2 virulence factors •Diphtheria is caused by Corynebacterium diphtheriae that belongs to group of Actinobacteria, Gram-positive bacteria with high GC content (50-75%). •The microbe is facultative anaerobic non-motile slightly bent pleomorphic bacilli. •It forms distinctive black colonies when it is grown on blood agar supplemented with tellurium. •Corynebacterium diphtheriae is part of normal flora, but it turns pathogenic only if become lysogenic for beta virus •Virulence factors: •Diphthin that acts as IgA protease •Diphtheria toxin is A-B type toxin that inhibits protein synthesis in targeted cells by binding to EF-2. Production of diphtheria toxin requires lysogenic conversion of bacterial cell by beta virus. Pathogenesis C. diphtheriae can grow only on the surface of human body without spreading into deeper layers •Bacterium turns pathogenic only if it is infected by beta (b) bacteriophage After lysogenic conversion, the viral gene for diphtheria toxin is expressed Free iron (Fe2+/3+) can effectively suppresses the toxin production "in vitro" Produced toxin is secreted by the bacteria, absorbed by the human body and enters circulatory system that delivers toxin to target cell The exotoxin has potential to cause damage to kidneys (majority of cases); heart muscle (in 20% of cases); nervous system (in 10% of cases) Mortality rate is up to 20%, even if disease is treated •Non-lysogenic Corynebacterium diphtheriae is part of normal flora and is not pathogenic. •C. diphtheriae lysogenic for beta virus produces and secretes diphtheria toxin in inactive form •Inactive toxin enters blood stream and spread in the body to all tissues •Via B-part, toxin binds to specific receptor located on plasma membrane of the target cell •The cell uptakes the toxin via endocytosis forming vesicle in the cytoplasm •The toxin is cleaved into A and B subunits, which activates A subunit. •The active A subunit enters cytosol and inhibits the proteins synthesis via binding to Elongation factor 2 (EF-2) and inhibiting the ribosome movement along mRNA •Diphtheria toxin can target kidneys, heart muscle and nervous system. Epidemiology •Reservoir: include: 1) People who have asymptomatic cases (about 5%); 2) People with active disease; 3) People recovered from the disease but are still carrying the bacteria; 4) Contaminated fomites ‒Humans only •Routes of transmission: ‒Respiratory droplets, ‒Direct contacts (hand shakes) ‒Indirect contacts (fomites) •Statistics: ‒World-wide data - about 4,000 cases annually. Decreasing. ‒US data - 60 cases in total (1980-2018) −Disease has strong ability to return (see slide notes and the graph) Classification: Contagious, Notifiable disease Diphtheria Epidemic -- New Independent States of the Former Soviet Union, 1990-1994 - MMWR, March 17, 1995 / 44(10);177-181 •Although diphtheria was controlled for approximately 30 years after the institution of childhood vaccination with diphtheria toxoid in the late 1950s, epidemic diphtheria has reemerged in the New Independent States (NIS) of the former Soviet Union. •The epidemic began in 1990 in the Russian Federation and spread to Ukraine in 1991 and, during 1993-1994, to 12 of the 13 remaining NIS. In most affected countries, the incidence rate of reported diphtheria has increased twofold to 10-fold each year. •This report summarizes data provided to the World Health Organization (WHO) about diphtheria in the NIS during 1989-1994. •Overall, reported cases of diphtheria in the NIS increased from 839 in 1989 to 47,802 in 1994 (Figure 1). •In 1994, a total of 1746 persons died; case-fatality rates ranged from 2.8% (Russian Federation) to 23.0% (Lithuania and Turkmenistan). Prevention •Quarantine ‒For those who are infected Antibiotics prophylaxis For those who were in contact with infected Vaccine First one was introduced in 1920 Currently it is DTaP that contains Diphtheria toxoid §Antibodies against diphtheria toxoid neutralize free diphtheria toxin but have no effect on bound toxin or the bacterium itself Immunity wanes 10 years after immunization §Boost immunization is required every 10 years •Quarantine •DTaP vaccine •It is part of the US immunization schedule •It includes inactivated diphtheria toxin (toxoid) ) that triggers production of protective antibodies. •Booster immunization is required every 10 years. •There is 85% coverage with 3rd dose of vaccine among 1 year-olds world-wide •over 95% coverage with 3rd dose of vaccine among 1 year-olds in the USA •About 50% of adult population in the USA does not have proper protection against diphtheria • Antibiotics prophylaxis •It is prescribed to anyone who was in contact with infected person. Treatment Antitoxin •It is the antibody produced in animals or human volunteers immunized with diphtheria toxoid (inactivated toxin) •It binds to free toxin and inactivates it. •It has no effect on the toxin that is already taken up by the target cell. Antibiotic treatment Penicillin and Erythromycin are antibiotics of choice They are given to kill a pathogen They also prevent production of new toxin and stop the spread of disease Antibiotics have not effect on toxin circulating in bloodstream Diphtheria antitoxin treatment First diphtheria antitoxin was introduced in 1894 It is antibodies against diphtheria toxoid produced in volunteers or in laboratory animals It is given to neutralize unbound diphtheria toxin already present in blood stream Antitoxin has no effect on already bound toxin or bacterium Effective treatment of diphtheria requires early application of antitoxin

Plague (black death)

Signs & symptoms Signs and symptoms depend on how the disease was contracted Bubonic plague It is contracted via infected flea bite 1-6 days after bite, person develops enlarged lymph nodes (buboes) Accompanied by high fever, delirium, patchy bleeding under the skin Pneumonic plague 1-3 days after inhalation of infected respiratory droplets, person develops −Cough, −High fever, −Delirium, −Pneumonia, −Blood in sputum, −Rapid shock, −Death Septicemic plague It develops if microbe enters bloodstream −Shock, −Disseminated intravascular coagulation, −Skin bleeding leading to black patchy rash Signs and symptoms There are 3 forms of plague, each has unique S&S: •bubonic plague •from 1 to 6 days after infected flea bite lymph nodes are enlarged and are forming buboes. •It is accompanied by high fever, delirium, patchy bleeding under the skin. •pneumonic plague •from 1 to 3 days after bacterium inhalation person develops cough, high fever, delirium, pneumonia with blood in sputum. •septicemic plague •It develops if pathogen enters bloodstream resulting in disseminated intravascular coagulation leading to reddish-black patchy skin rash. Etiological agent Yersinia pestis Virulence factors: Biofilm; Capsule; Type III secretion system; Endotoxin ‒Virulence factors encoded by 3 plasmids §F1 is part of capsule §Pla destroys C3b, C5a, blood clots §V antigen controls type III secretion system §YOP proteins inhibit phagocytosis, immune response Gram-negative Facultative anaerobe Mesophilic bacillus ‒Virulence factors encoded by bacterial chromosome §Spa A - adhesin •Disease is caused by Yersinia pestis that Gram-negative facultative anaerobic, mesophilic bacilli. •It produces capsule, forms biofilm and has type III secretion system •Some virulence factors are encoded on chromosome •PsaA protein (adhesin). •Other virulence factors are encoded by 3 plasmids: •F1 protein (part of capsule), Pla protein (plasminogen that destroys C3b, C5a, clots), V antigen (control type III secretion system), YOP proteins (interferes with digestion by macrophages and immune response). Pathogenesis Yersinia pestis enters the host via flea bite and delivered to lymph node Pathogen replicates inside macrophage causing acute inflammation reaction Bacteria released from necrotic buboes enter the bloodstream, turning bubonic plague in to septicemic form (both are non-contagious) If Yersinia pestis enters lungs, plague turns to contagious pneumonic form If disease left untreated, mortality rate ranges from 50% to 90% •Y. pestis enters host via flea bite. •Pla protein inactivates compliment system and prevents formation of blood clots. •Microbe is delivered to lymph node where it is ingested by a macrophage. •Bacteria replicates inside macrophages causing acute inflammation reaction that leads to enlargement of lymph node, forming "buboes". •Large number of bacteria is released from necrotic buboes into blood stream turning bubonic plague into septicemic one accompanied by skin hemorrhage, shock, disseminated intravascular coagulation and death. Epidemiology Classification: Contagious (~20% of cases), Notifiable zoonosis Statistics: World-wide data §There are about 10,000 cases reported annually. Most of cases are reported in Madagascar, Congo The US data §Disease is sporadic (10-100 cases annually) due to rodent control. Reservoirs: Rodents (Prairie dogs, Rats) Routes of transmission: Bite of infected flea (main RT) Respiratory droplets from patients with pneumonic form Prevention •Rodent control ‒The most important preventive measure •Quarantine ‒For those who are infected Vaccine NONE Antibiotics prophylaxis Tetracycline is prescribed for those who were in contact with infected Treatment Antibiotic treatment Broad spectrum antibiotics like Gentamycin, Ciprofloxacin It is effective if antibiotics are given within 24 hours from onset of symptoms

Salmonella gastroenteritis

Signs & symptoms •Incubation period from 12 hours to 3 days •Disease starts with ‒Stomach cramps; ‒Nausea; ‒Vomiting ‒Diarrhea •Severe cases are rare: ‒Fever; ‒Diarrhea turns severe & bloody •S&S are lasting for up to 7 days Etiological agents Salmonella enterica, serotypes Typhimurium & Enteritidis. Others species: S. anteritidis, S. bongori •Gram-negative •Motile (peritrichous) bacilli •Facultative anaerobe •Virulence factors: ‒Type III secretion system ‒Effector proteins ‒Endotoxin (heat-resistant LPS) ‒Variety of exotoxins Pathogenesis S. enterica is sensitive to stomach acids & ID50 is over 106 cells •Upon reaching distal end of small intestines, microbe binds to epithelial cells •Binding of S. enterica to cellular receptors activates Type III secretion system - see lecture 6 for details •Type III secretion system delivers microbial effector proteins to targeted cell triggering membrane ruffling •Membrane ruffling initiates directed uptake of the microbe by epithelial cell via endocytosis •Up-taken microbe multiply within the phagosome and are discharged from the cell at basal membrane •microbes released from the cells survive the attack by macrophages and kill them •Some microbes escape phagosomes and replicate directly in cytoplasm •Inflammation and toxin production increase the fluid secretion leading to diarrhea Epidemiology Reservoirs: Reptiles; Birds Routes of transmission: Oral-Fecal route, ID50 = 108 −Food contaminated by feces (Vehicles) §Poultry; Eggs §Produce −Pet-carriers (Direct contact) §Turtles, Iguanas, Chickens ‒Hands contaminated by feces Classification: Communicable, Notifiable zoonosis Statistics: World-wide data §Estimated over 100,000,000 cases annually The US data §Over 50,000 cases reported annually. On increase. §Most cases are associated with contaminated food of animal origin or infected pets Microbe is readily found in animals and can survive outside of the host for long time §It does not cause the disease in animals and birds and, therefore, they can be asymptomatic carriers How do people get infected by Salmonella? •Salmonella live in the intestinal tracts of humans and animals, including birds. •Salmonella are usually transmitted to humans via food contaminated with animal feces. •Contaminated foods usually look and smell normal. •Contaminated foods are often of animal origin, such as beef, poultry, milk, or eggs, but any food, including vegetables, may become contaminated. •Food may also become contaminated by the hands of an infected food handler who did not wash hands with soap after using the bathroom. •Salmonella may also be found in the feces of some pets, especially those with diarrhea, and people can become infected if they do not wash their hands after contact with pets or pet feces. •Reptiles, such as turtles, lizards, and snakes, are particularly likely to harbor Salmonella. •Many chicks and young birds carry Salmonella in their feces. Some of the latest salmonellosis outbreaks in the US Multistate outbreak linked to bean sprouts As of 11/24/2014 : 68 people infected, 26% are hospitalized, 10 NE states were involved Outbreak linked to live poultry in backyard As of 10/21/2014 : 363 people were infected in 43 states; 33% were hospitalized Prevention Vaccine None Epidemiological surveillance Reporting and tracing the outbreaks to their source Good hygiene Hands washing after pets handling Food safety Avoid eating raw, undercooked eggs, poultry or meat Prevent cross-contamination of food Store separately uncooked food from cooked and ready to eat food Hands washing after touching uncooked food Prevention •Buy eggs only from stores or other suppliers that keep them refrigerated. •Consumers can consider buying and using pasteurized shell eggs, which are available for purchase from certain stores and suppliers. •Keep eggs and chicken refrigerated. •Discard cracked or dirty eggs. •Wash hands and cutting boards, dishes, utensils, and counter tops with soap and water after contact with raw eggs or raw chicken. •Eggs should be thoroughly cooked until both the yolk and white are firm. Recipes containing eggs mixed with other foods should be cooked to an internal temperature of 160ºF (71ºC). •Chicken should be cooked until the internal temperature reaches 165ºF (74ºC). •Eat eggs promptly after cooking. Do not keep eggs warm or at room temperature for more than 2 hours. •Refrigerate unused or leftover foods promptly. •Avoid eating raw eggs (as in homemade ice cream or eggnog). Commercially manufactured ice cream and eggnog are made with pasteurized eggs. •Avoid restaurant dishes made with raw or lightly cooked, unpasteurized eggs. Restaurants should use pasteurized eggs in any recipe (such as Hollandaise sauce or Caesar salad dressing) that would result in consumption of raw or lightly cooked eggs. Treatment Most cases are resolved without treatment within 7 days Hospitalization may be required in severe cases Antibiotic treatment It is usually not advised unless it is severe case Salmonella enterica strains have shown multidrug resistance Most likely it is due to wide-spread use of sub-therapeutic levels of antibiotics in animal feeds

Influenza

Signs and Symptoms Short incubation period - up to 2 days Person become infective 1 day before S&S Headache, Fever, Muscle pain, Dry cough Acute symptoms abate within a week Cough and fatigue may linger Etiological agent Influenza viruses types A, B, C Viral genome Single-stranded RNA genome Types A & B: It is divided into 8 segments Type C: genome is divided into 7 segments Viral envelope (type A and B virus): Hemagglutinin is adhesin, used in detection & identification of virus Neuraminidase is enzyme that is involved in budding during virus replication Etiological agent •Disease is caused by enveloped influenza virus (types A, B, or C), whose single stranded RNA genome is divided into 8 (A or B) or 7 (C) segments. •The envelop has two essential proteins - •Hemagglutinin that functions as viral adhesin and can agglutinate RBC, which is used in ID of virus •Neuraminidase, an enzyme that is involved in budding off newly assembled viral particles from host cell. •The virus has ability to rapidly mutate due to antigenic drift and antigenic shift. • Antigenic drift •It is characteristic to any RNA virus - due to high rate of mutation during genome replication. •Viral genome is changing at slow pace. Antigenic shift •It is a result of infection of the cell by two different viral strains at the same time resulting in mixing of the viral genes/proteins and appearance of new recombinant viral strains. •Viral genome is changing abruptly. Pathogenesis Virus attaches to epithelial cells via hemagglutinin This protein is used in diagnostics of the infection Virus is temperate and slowly replicates in host cell Newly produced virions are released via budding avoiding outright killing the cell Infected cell is eventually dying, which leads to inflammation reaction This sets off signs and symptoms of the disease Humoral immune response (antibodies) suppresses the viral replication Epidemiology •Classification: ‒Contagious, Notifiable disease (Zoonosis) Reservoirs: humans, Animals and birds Routes of transmission: ‒Respiratory droplets ‒Direct contacts (hand shakes) ‒Indirect contacts (fomites) Statistics: World-wide data - outbreaks occur annually with over 500,000 deaths §Virus has segmented RNA genome, enabling it to go via antigenic drift and antigenic shift US data (2018-19 season) - 42,900,000 cases; 647,000 were hospitalized and 61,200 deaths Statistics: World-wide data - outbreaks occur annually with over 500,000 deaths §Virus has segmented RNA genome, enabling it to go via antigenic drift and antigenic shift US data (2018-19 season) - 42,900,000 cases; 647,000 were hospitalized and 61,200 deaths •Classification: Contagious, Notifiable disease (Zoonosis) Prevention New vaccine is required every year Vaccine •It is produced from attenuated viruses grown in embryonated eggs. •Vaccine is effective 80% to 90% Treatment Antiviral drugs (see slide notes •Neurominidase inhibitors prevent budding of the viral particles off the cells •Tamuflu, Relenza, Inavir •M2 proton channel inhibitors prevent replication of virus inside the cell •Amantidine, Rimantidine. •They are about 70-90% effective if taken early Antigenic drift (slow changes) •It is characteristic to any RNA virus. •Influenza virus is undergoing antigenic drift because it has RNA genome •RNA polymerase producing copies of viral RNA genome does not have proof-reading capabilities. •Which means that any nucleotide wrongly inserted in newly synthesized copy of viral RNA genome would stay there. Antigenic shift (rapid changes) •It can occur in any virus that has segmented genome •Influenza virus is undergoing antigenic drift (slow changes) because it has segmented genome (divided into 7-8 segments). •Antigenic shift occurs when two different strains of influenza virus infect the same cell: newly assembled virions (viral particles) in such cell would have assorted (mixed) segments of RNA genome. •For example, if the cell is infected by two influenza viruses with genomes completely different from each other and each divided into 8 segments, such cell would produce 8^2 = 64 types of recombinant influenza viruses.

Infectious mononucleosis

Signs and symptoms Symptoms appear after long incubation period Usually 30 to 60 days post infection Symptoms include fever, sore throat covered with pus, fatigue, enlarged lymph nodes and spleen In most cases fever and sore throat disappear within 2 weeks, Lymph node enlargement disappears within 3 weeks Generally, people recover completely in 4 weeks Etiological agent Infection is caused by Epstein-Barr virus of herpesvirus family. •It is double stranded DNA enveloped virus Pathogenesis (lect 11, slide 37, steps) •Epstein-Barr virus infects and kills epithelial cells in throat and mouth resulting in pharyngitis. •Virus enters lymphatic vessels and become trapped in lymph nodes. •Virions escaped lymph nodes enter blood stream and infect B cells. •If virus replicates, infected B cells are killed by T cytotoxic cells. •If virus turns in to provirus, the infected cell is immortalized and actively divides. •Newly produced B cells turn into plasma cells. •Since the virus infects B cells randomly, the plasma cells produce various antibodies called heterophile as they recognize various antigens. • The Epstein-Barr virus (EBV) infections has been linked to increased risk of seven other diseases: •systemic lupus erythematosus (SLE), •multiple sclerosis (MS), •rheumatoid arthritis (RA), •juvenile idiopathic arthritis (JIA), •inflammatory bowel disease (IBD), •celiac disease, •type 1 diabetes. Epidemiology Reservoirs: Humans only Routes of transmission: Respiratory droplets, mainly via mouth to mouth kissing (=> "kissing disease") Indirect contacts via shared water bottles, drinking caps, toothbrushes •Classification: ‒Contagious, Notifiable disease Statistics: ‒Disease distributed world-wide, particularly in crowded, economically disadvantaged areas §Infects at early age without producing symptoms and is resulting in immunity ‒More affluent populations are missing exposure and generally are lacking immunity §Disease occurs almost exclusively in adolescents and adults who lack immunity ‒Virus can persist in saliva for up to 18 months Prevention Vaccine NONE Good hygiene Avoid exposure to saliva of another person Avoid sharing toothbrush, Avoid sharing drinking caps, water bottles Treatment Anti-viral treatment Acyclovir inhibits productive infection but it has no activity against latent virus

Mumps

Signs and symptoms •It is acute viral infection that affecting parotid & salivary glands ‒In rare occasions it affects pancreas, and meninges ‒In adolescents and adults it may also involve ovaries, testicles •Incubation period for up to 3 weeks, S&S last for 2 weeks. •It starts with loss of appetite, headache, fever, ‒Then followed by painful swelling of one or both parotid glands, earache, pain while talking or chewing. •Adolescents and adults often may also have severe S&S: ‒Men suffer from orchitis, painful swelling of testicles with possible reduced fertility or sterility. ‒Women (20% of infected) may suffer from pelvic pain due to ovary infection. Pregnant women often have miscarriage. ‒In older: meningitis or even death. Etiological agent Mumps virus is enveloped virus with single-stranded RNA(-) genome •It belongs to paramyxovirus family that is shared with Rubeola virus •It causes acute viral infections only •Besides parotid glands, it may also infect meninges, pancreas, ovaries, testicles Pathogenesis •Replicating virus is causing very strong inflammatory response leading to signs and symptoms ‒Dying cells are releasing enormous amount of virus in saliva and urine •COMPLICATIONS: ‒Deafness; Meningitis; Miscarriage, Orchitis (often); Male sterility (rarely) •Virus enters upper respiratory tract and replicates in nasopharynx asymptomatically resulting in relatively long incubation period. •Then, virus enters bloodstream and spreads throughout the body infecting ducts of parotid gland. •Other body parts that can be infected by mumps virus are pancreas and tubules of ovaries, testicles or kidneys. •Replicating virus is causing strong inflammatory response leading to developing severe swelling of parotid gland and pain. •Swelling in testicles may obstruct the blood flow and lead to hemorrhage and tissue necrosis - it may lead to reduced fertility in men but it rarely causes sterility. •Infection in pregnant women lead to miscarriage. •Dying cells release enormous amount of virus to saliva and urine (if ovaries or testicles are infected). Epidemiology •Classification: ‒Contagious, Notifiable disease •Reservoir: ‒Infected humans only •Routes of transmission: ‒Respiratory droplets, ‒Direct contacts (hand shakes) ‒Indirect contacts (fomites) •Statistics: ‒World-wide data - 400,000 cases annually ‒US data - about 1,000 cases annually ‒Mumps is good candidate for eradication: §Infection leads to strong life-long immunity §Only one reservoir; Only one serotype §Virus does not cause latent infections •Mumps is contagious, notifiable disease with humans as only reservoir. •It is transmitted via respiratory droplets, direct and indirect contacts. •Infected become infective a week before S&S onset. •The disease is largely under control due to immunization campaign. Still, outbreaks occur: in 2015 there were about 400,000 mumps cases reported world-wide and over 1,000 mumps cases in the USA. •It is a good candidate for eradication: •Single host, •Only active infection that leads to strong life-long immunity. Prevention •Quarantine •Vaccine ‒Currently it is MMR vaccine •Quarantine infected for 5 days to limit the spread of disease. •MMR vaccine contains attenuated mumps virus and is 90% effective. Treatment •No treatments •Antibiotic treatment ‒Only for secondary infections caused by bacteria

Scientists discovered this novel protein while studying what mechanism in Hydra?

Skin defenses Hydramacin was discovered while researching defense mechanisms in the skin of this organism.

Identify the risk factors associated with the tattooists in this case.

Some of them used printer ink for the tattoos. Some tattooists had skin lesions while working. The tattooists did not sterilize their equipment between clients. They were unlicensed.

What is novel and exciting about the compounds isolated by this research team?

Some of them work on dormant bacteria as well as replicating bacteria, rather than only on dividing bacteria like the antibiotics currently used.

Proteins that project or stick out from the envelope of HIV and attach or adsorb it to host cells are called ______.

Spikes Glycoprotein spikes are found on the outside of the membrane of enveloped viruses.

Why is the treatments of infections caused by S. aureus require the use of semi-synthetic penicillins?

Staphylococcus aureus is naturally susceptible to virtually every antibiotic that has ever been developed. Resistance is often acquired by horizontal transfer to genes from outside sources, although chromosomal mutation and antibiotic selection are also important. This exquisite susceptibility of S. The treatment of choice for S. aureus infection is penicillin. In most countries, S. aureus strains have developed a resistance to penicillin due to production of an enzyme by the bacteria called penicillinase Staphylococcal resistance to penicillin is mediated by blaZ, the gene that encodes β-lactamase (Figure ​ 2a). This predominantly extracellular enzyme, synthesized when staphylococci are exposed to β-lactam antibiotics, hydrolyzes the β-lactam ring, rendering the β-lactam inactive.

Infections of upper respiratory system

Streptococcal pharyngitis (Strep throat) Diphtheria Common Cold

Select which of the following microbial control methods WERE NOT followed by the interviewed tattooists in this case.

Tattooists changed gloves between clients. Tattooists used new needles on each client. Tattooists cleaned the client's skin with disinfectant before the procedure. Tattooists used new ink pots for each client.

Inhibition of metabolic pathways - Folic acid biosynthesis

Sulfa drugs & Trimethoprim Both antibiotics are •Bacteriostatic, •Broad spectrum •They are competitive inhibitors of the enzymes involved in folic acid biosynthesis −The folic acid biosynthesis pathway is absent in human cells •The combined use of both antibiotics has synergistic effect −Effect of combined use is greater than the use of either antibiotics separately Folic acid •It is precursor of nucleotides and also used in synthesis of coenzymes •Folic acid biosynthesis pathway is present in bacterial cells. •Folic acid biosynthesis pathway is not present in humans. •As a result, humans have to get folic acid from the food Sulfanilamide •It is competitive inhibitor of dihydropteroate synthetase, the enzyme catalyzing the first step of metabolic pathway of folic acid biosynthesis •Substrate of dihydropteroate synthetase is PABA •Sulfanilamide has structural similarities to PABA •It competes with PABA for binding to active site of dihydropteroate synthetase. •Sulfanilamide is effective antimicrobial drug. •Antibiotic has very high therapeutic index •Combined use of sulfanilamide and trimethoprim has synergistic effect •Trimethoprim inhibits another enzyme of metabolic pathway of folic acid biosynthesis •Mechanism of microbial resistance: Acquisition of the plasmid carrying the genes of alternative enzymes •Side effects relatively rare: Stevens Johnson syndrome - necrosis of epidermal cells leading to separation of dermis from epidermis. Type I allergy

Which of the following antimicrobials inhibit bacterial metabolic pathways such as folate biosynthesis?

Sulfonamides Trimethoprim

Match each of the following autoimmune diseases with its major mechanism of tissue damage.

T cells destroy pancreatic islet (beta) cells - (1) - Type 1 diabetes mellitus Autoantibodies form immune complexes in small blood vessels. - (4) - Systemic lupus erythematosus (SLE, lupus) Autoantibodies prevent muscle contraction. - (3) - Myasthenia gravis Lymphocytes destroy joint tissues. - (5) - Rheumatoid arthritis Autoantibodies cause overstimulation of thyroid. - (2) - Graves' disease Each of these diseases results from damage caused by the immune system. However, the mechanism of this damage-induction is different in each disease. Sometimes it's antibody-related; other times it's mediated by specific T cells. Knowing the immune response that causes the damage can lead to development of better therapies to fight the illness.

Immunosuppressive medications such as cyclosporin A and tacrolimus suppress cellular-signaling mechanisms in

T lymphocytes, suppressing T cell proliferation and responses.

WHAT was the reason in replacement of DTP or DTwP vaccine with DTaP?

The United States switched from whole cell to acellular pertussis vaccines in the 1990s following global concerns with the safety of the whole cell vaccines. Despite high levels of acellular pertussis vaccine coverage, the United States and other countries are experiencing large pertussis outbreaks. Researchers have proposed a number of ideas for the increase, including increased awareness of the disease and better diagnostic techniques. Others have suggested that fewer people were getting the vaccine, and some thought that the new vaccine's ingredients were less effective.

What is a possible reason that the compounds isolated from the sponges may not be useful for treating TB in people, even though in vitro tests indicate that they are effective against this organism?

The concentration of the compound used in vitro may prove to be toxic in humans.

Pneumonia

inflammation of the lungs with filling of the air sacs with fluids, pus, or blood

History of antimicrobial drugs

The first synthetic (arsenic) compound used as antimicrobial drug It is effective against Treponema pallidum that causes syphilis When in cell, it is metabolized and it is split forming sulfanilamide It is effective against infections caused by Streptococcus spp.

PCV-13 is used in immunization of adults only. WHY the use of PCV-13 had reduced the prevalence of pneumococcal disease among young children as well?

The licensure (in 2000) and subsequent widespread use of a heptavalent pneumococcal conjugate vaccine (PCV7) have had a significant impact on decreasing the incidence of serious invasive pneumococcal disease (IPD) in all age groups, especially in children under 2 years of age. Widespread use of PCV7 and PCV13 in children has led to sharp declines in pneumococcal disease among unvaccinated children and adults by preventing carriage, and thereby transmission, of vaccine-type strains Streptococcus pneumoniae (pneumococcus) can cause serious illness, including sepsis, meningitis, and pneumonia with bacteremia (invasive) or without bacteremia (noninvasive). Since the early 1980s, PPSV23 has been recommended for persons aged ≥2 years with certain underlying medical conditions, and all adults aged ≥65 years (3). 7-valent pneumococcal conjugate vaccine (PCV7) was introduced into the routine pediatric immunization schedule in 2000 and was replaced by PCV13 in 2010 (4). In 2012, PCV13 was recommended in series with PPSV23 for adults aged ≥19 years with immunocompromising conditions, CSF leaks, or cochlear implants (2). In 2014, PCV13 was recommended for all adults aged ≥65 years (1,5). Widespread use of PCV7 and PCV13 in children has led to sharp declines in pneumococcal disease among unvaccinated children and adults by preventing carriage, and thereby transmission, of vaccine-type strains (Figure). In 2014, ACIP recognized that, while in the short-term, routine PCV13 use among adults aged ≥65 years was warranted, in the long-term, continued indirect effects from PCV13 use in children might limit the utility of this recommendation. In addition, models predicted limited public health benefits in the long-term, given the relatively low remaining PCV13-type disease burden (1). Therefore, ACIP proposed that the recommendation for routine PCV13 use among adults aged ≥65 years be evaluated 4 years after implementation of the 2014 recommendation.

What are possible mechanisms of microbial resistance to vancomycin?

The main mechanism of glycopeptide resistance (e.g., vancomycin) in enterococci involves the alteration of the peptidoglycan synthesis pathway, specifically the substitution of D-Alanine-D-Alanine (D-Ala-D-Ala), to either D-Alanine-D-Lactate (D-Ala-D-Lac) or D- Alanine-D-Serine (D-Ala-D-Ser) Bacterial resistanceVancomycin resistance is caused by an altered peptidoglycan terminus (d-ala-d-lac instead of the usual d-ala-d-ala), resulting in reduced vancomycin binding and failure to prevent cell wall synthesis. Resistance in vancomycin-intermediate S. aureus and glycopeptide-intermediate S. Vancomycin resistance is acquired when a sensitive Enterococcus acquires a special piece of DNA called a plasmid that permits the bacteria to become resistant to vancomycin. The new strains are called vancomycin-resistant enterococci (VRE).

Which antibiotic is more likely to disturb normal microbiota, broad- or narrow-spectrum?

The medications most likely to disrupt the normal gut microbiome are antibiotics, with broad-spectrum antibiotics contributing most to microbiome disturbance. Broad-spectrum antibiotics are antibiotic medications that are effective against both gram-positive as well as gram-negative bacteria3. These antibiotics are commonly used when a bacterial infection is present, but there is a lack of time or resources and treatment needs to be administered immediately.Throughout history, broad-spectrum antibiotics have saved countless lives and enabled advancements in surgery and treatment for hospital-acquired infections. However, while extremely useful, broad-spectrum antibiotics have been associated with acquired allergies and are the main contributing cause of the antibiotic resistance crisis. The most common broad-spectrum antibiotics used in humans are: Narrow-spectrum antibiotics target a few types of bacteria. Broad-spectrum antibiotics target many types of bacteria. Both types work well to treat infections. But using broad-spectrum antibiotics when they're not needed can create antibiotic-resistant bacteria that are hard to treat. Narrow-spectrum antibiotics have been shown to be effective when the bacterial genus or species is known. However, clinicians need to diagnose the offending bacteria rapidly and accurately before an infection becomes too severe.Clinicians need additional resources and training to understand what types of bacterial species can be targeted with narrow-spectrum antibiotics and when these can be effective4.

Please select the TRUE statements regarding this case.

The skin infections identified in this case are contagious Herpes gladiatorum is a viral skin infection. Wrestlers are at risk of skin infections because of the nature of the sport.

Chemotherapy

The use of chemical compound to treat a disease.

Pharyngitis

inflammation of the throat

How was hepatitis C spread at the dialysis center?

Through improper disinfection practices Hepatitis C is spread through blood-to-blood contact, and in this case, transmission of the virus was through improper disinfection practices between patients and by the staff not wearing gloves or washing their hands.

Match the antimicrobial medications with the ribosomal subunit to which they bind. Not all labels are used.

Top 50S Streptogarmins Chlorhamphenical Oxazolidinones Lincosamides Macrolides Bottom 30S Tertracyclines Glycylcyclines Aminoglycosides Streptogamins, chloramphenicol, oxazolidones, lincosamides, and macrolides all affect the large ribosomal subunit.

Match the labels with the correct areas it describes in this image of an E (epsilometer) test. Not all labels are used.

Top to Bottom -type of antibiotic indicated here -Highest antibiotic concentration -MIC value read here -lowest antibiotic concentration The E test is used to determine antibiotic sensitivity and MIC. The name of the antibiotic is given at the top of the strip. The antibiotic concentration decreases along the strip from the top down. The MIC is read at the point where the bacterial growth intersects the strip.

T/F After complement activation, basophils may degranulate, releasing mediators that cause vasodilation.

True

T/F Attachment of HIV to a host cell requires a receptor and co-receptor on the surface of the host cell.

True

T/F For poliomyelitis eradication to be successful globally, both IPV and OPV should be included in the vaccine strategy.

True

T/F Some antibiotics fail to kill/inhibit a pathogen simply because the microbe is naturally (intrinsically) resistant to it

True

T/F. Human bite wounds are usually infected with both aerobic and anaerobic species of mouth bacteria.

True

T/F. The anti-Mycobacterium tuberculosis compounds isolated from sea sponges by the research team in this case are made by microbes living in the sponges.

True

True or False: Histoplasma is endemic to Central and South America, and areas in the United States.

True Histoplasma capsulatum, and its associated disease histoplasmosis, can be observed in Central/South America and even in the Ohio River Valley in the United States.

T/F Hydramacin needs to be tested in human trials.

True One important phase of testing is to determine if a compound has any toxic effects on the patient.

Please categorize the statements according to the type of hypersensitivity.

Type I: -hives -asthma -shock -mediated by histamine -involves basophils and mast cells -causes skin wheals and flares Type II: -transfusion reactions -hemolytic disease of the newborn -mediated by ADCC -involves NK cells -causes no skin reactions Type III: -involves phagocytes -causes arthus reaction in skin -serum sickness -disseminated intravascular coagulation -mediated by neutrophil enzymes Type IV: -causes skin inflammation -contact dermatitis -involves dendritic cells -mediated by T cell cytokines -tuberculin reaction Type I hypersensitivity reactions are IgE-mediated and result in anaphylaxis and allergic reactions. Type II involve antibody-coated cells with complement activation resulting in lysis. Type III is due to circulating immune complexes that are deposited in the basement membranes. Type IV is delayed hypersensitivity and results in cytotoxic reactions in tissues.

Pathogenesis

Varicella (chickenpox) Chickenpox Virus infects & replicates in mucosa of respiratory system Virus enters blood stream and is delivered to the skin. Dying infected skin cells are triggering inflammation and formation of vesicles Virus may enter peripheral neurons and turn in to provirus. Shingles (herpes zoster) Reactivated virus moves along infected neuron to skin, infects keratinocytes, causing the appearance of painful shingles Reactivation is correlating with the decline of immunity COMPLICATIONS: •Secondary infections; •Congenital varicella syndrome with various birth defects

Skin Infections Caused by Viruses

Varicella (chickenpox) Rubeola (measles) Rubella (German measles) These diseases are classified a endogenous skin disease since etiological agents are delivered to the skin via circulatory system

Key Concept Activity: Diseases of the Respiratory System Please assign the diseases to either the upper or the lower respiratory tract on the figure. Not all labels are used.

Upper Respiratory System Adenoviral pharyngitis common cold diphtheria strep throat Lower respiratory system pneumonia leigonellosis RSV infections Tuberculosis Influenza Histoplasmosis Coccidiomycosis Hantavirus pulmonary syndrome Pertussis

Anatomy, physiology, and ecology

Upper digestive system •Oral cavity and tongue - mechanical digestion of food •Salivary gland - produces saliva that contains amylase, the enzyme participating in starch digestion •Epiglottis - prevents food from entering trachea •Esophagus - muscular tube that delivers food from mouth to stomach •Stomach - chemical digestion of food. It produces stomach juice containing pepsin and 2N HCl that partially digests proteins Saliva It contains lysozyme that digest cell wall and lead to bacterial cell lysis It contains Ig A It also has amylase Microbes are removed mechanically Lower digestive system •Pancreas - produces pancreatic juice containing multiple digestive enzymes - proteases, nucleases, lipases, and enzymes digesting carbohydrates •Liver - produces bile, the juice aiding in digestion of fats •Gallbladder - stores bile until it is used in digestion •Small intestines - it is the major place of food digestion and absorption of nutrients •Appendix - unlike to animals, in humans it does not play any role in digestion •Large intestines - place of water absorption and where most of normal flora resides •Rectum - place where feces are forming •Anus - controls the waste expulsion Gastric juice It kills practically all microbes It contains pepsin, a protease and concentrated hydrochloric acid pH 2 kills most microbes upon their entry in to stomach Some microbes like Helicobacter & Shigella can survive stomach's acid Most microbes are found in large intestines

If person is infected with herpes virus, that person would carry the virus for the rest of life. WHY?

When the sores have healed and the skin looks normal again, the virus hides in the nerve cells under the surface of the skin. Once someone is infected with the herpes virus, he or she will have the infection for the rest of his life. Herpes is challenging to cure because of the nature of the virus. The HSV infection can hide away in a person's nerve cells for months or years before reappearing and reactivating the infection Herpes is forever. When one of the sexually transmitted virus' two strains enters the body through genital tissue, it travels to neurons near the spine that the body's defenses have learned not to kill - even when infected - because they don't regenerate easily.

Select which of the following were Maricopa County Department of Public Health recommendations for schools with wrestling teams.

Wrestlers should be provided with hand sanitizer at practice and competition Wrestlers should shower before each match. Wrestlers with uncovered lesions should be excluded from competition

Why are wresters particularly at risk of skin diseases?

Wrestling is a sport that involves a lot of skin-to-skin contact.

The Kirby-Bauer disc diffusion test is used to determine

antimicrobial susceptibility. The Kirby-Bauer disc diffusion test is used to determine bacterial susceptibility to various antimicrobial agents.

Firmicutes

are Gram-positive bacteria that have low GC-content in DNA (24-50%). •Gram-positive facultative anaerobes •Salt-tolerant; Catalase-positive; Growing as cocci in clusters •Staphylococcus epidermidis It is part of normal flora in humans. It does not produce virulent factors and has no ability to invade human host. •However, some strains may form biofilms: •It is the principal staphylococcal species found on skin that plays a vital role in limiting the skin colonization by pathogens •It may represent danger to immuno-compromised patients only The growth on blood agar. Note the color of colonies and lack of hemolysis •It prefers to grow on the skin. •Plays vital role in limiting colonization of the skin by pathogen •Does not produce any virulence factors and lacks ability to invade. −However, it can form biofilm •Staphylococcus aureus - it is OPPORTUNISTIC PATHOGEN that is part of normal flora in humans. Still, various strains of S. aureus can cause various infections in humans depending on what virulence factors are produced: •Capsule/Biofilm interfere with ingestion by phagocytes and helps microbe survive treatment by antibiotics •Adhesins - Clumping factor A binds to fibrin, fibrinogen, plastic devices; FnBPA (fibronectin-binding protein A) binds to acellular tissue substances and plastic devices. •Protein A binds IgG inverted thus interfering with phagocytosis (prevents ingestion) •Enzymes - penicillases and b-lactamases - digest penicillins and b-lactam antibiotics, Catalase - inactivated hydrogen peroxide produced by attacking macrophages; Coagulase - deposit human proteins on bacterial cell and, thus interfering with phagocytosis. It is found in the most virulent strains. Hyaluronidase - breaks connections between the cells in human tissue thus increasing microbe invasiveness. Staphylokinase - dissolves blood clots thus increasing microbe invasiveness •Exotoxins - Superantigen (TSST-1) nonspecifically activates T-helper cells resulting in "cytokine storm". Exfoliative toxin - protease digesting desmoglein I that holds keratinocytes (skin cells) together; a-, b- toxins - membrane-disturbing toxins (pore-forming and lipid-digesting, respectively); Leukocidin is secretory toxin that kills phagocytes by forming pores in their plasma (cytoplasmic) membrane. •Penicillin-binding protein 2a - does not bind penicillin, resulting in bacterial resistance to penicillin. •Staphyloxantin inactivates hydrogen peroxide produced by attacking macrophages The growth on blood agar. Note the color of colonies and presence of hemolysis •It prefers to grow in nasal chambers. •Opportunistic pathogen •It can produce multiple virulence factors −See slide notes and Lecture 9 for more details

Bacteriostatic antibiotics

are effective only if their concentration reach certain level in microbial cell. These antibiotics stop microbial growth but do not kill them. Microbes would resume the growth after drug withdrawal, as soon as concentration of antibiotic falls below certain level. EXAMPLES: Tetracycline, Erythromycin •If infection is caused by Gram-negative bacteria, bacteriostatic antibiotics must be used in treatment of the infection.

Bactericidal antibiotics

are killing the microbes. If bactericidal drug is removed, microbial growth would not resume. EXAMPLES: Penicillin, Streptomycin •Minimal bactericidal concentration is the lowest concentration that kills 99.9% of microbes •If infection is caused by acid-fast bacteria, only bactericidal antibiotics must be used in treatment.

Symptoms of disease

are what can be felt by a patient only

Signs of disease

are what can be observed by anyone

Inhibition of cell wall synthesis

b-lactam drugs •They compete with side chain for active site of PBP •They include penicillins and cephalosporins that are inhibiting the synthesis of bacterial cell wall by binding to active site of penicillin-binding protein and thus preventing the cross-linking of peptidoglycan polymeric fibers. •Bacterial resistance to beta-lactams - 1) mutation in penicillin-binding protein so that it no longer binds penicillin but it is still can cross-link peptidoglycan fibers; 2) microbe produces enzyme (penicillases or b-lactamases that break down the b-lactam ring of penicillins or cephalosporins. •Natural penicillins are narrow spectrum antibiotics, while semi-synthetic penicillins and cephalosporins are broad spectrum antibiotics. •It can be administered intravenously or orally. Vancomycin •It competes with PBP for binding to peptide side chain Vancomycin can not cross outer membrane of Gram negative bacteria •It is inhibiting the synthesis of bacterial cell wall by binding to side chain of NAM-NAG and thus preventing cross-linking of peptidoglycan polymeric fibers. •Bacterial resistance to vancomycin - mutation in pentapeptide side chain of NAM-NAG that replaces the terminal alanine (Ala) with lactic acid, so that it no longer binds vancomycin but it is still can be cross-linked by penicillin binding protein. •It is narrow spectrum antibiotic as it can not cross outer membrane of Gram negative bacteria. and, therefore, it can be used against Gram positive bacteria only. •It must be administered only intravenously due to it's poor absorption from intestinal tract Bacitracin •It interferes with delivery of cell wall precursors Bacitracin is toxic to humans as it disturbs plasma membrane of human cells •It is inhibiting the transport of peptidoglycan precursors across membrane, from cytoplasm to site of cell wall synthesis •It inhibits cell wall synthesis by interfering with transport of peptidoglycan precursors across plasma membrane. The drug inhibits de-phosphorylation of bactoprenol-phosphate that is a carrier for the precursors. •However, due to high toxicity, it's use is limited to topical applications. It is a common ingredient in non-prescription first-aid ointments

The HIV proviral DNA inserted into the host cell's DNA is used to make

both viral genome RNA and viral mRNA. HIV mRNA is made which directs host cells to make the HIV proteins, and multiple copies of genome RNA are synthesized which will be "wrapped" inside newly made capsids.

Histoplasma often grows in the droppings of

bats and birds. Hantavirus is contracted from dust contaminated with mouse urine, while Histoplasma often grows on bat or bird droppings.

If you can block the effect of HIV protease, you will

block cleavage of the HIV polyprotein into individual proteins. Blocking the effect of HIV protease will block cleavage of the HIV polyprotein into individual proteins

If hydramacin exhibits selective toxicity in experiments, it will

cause no damage to host tissues. A medication exhibiting selective toxicity kills or inhibits microbial cells but does not cause host cells any damage.

Inactivated whole agent vaccines

contain bacteria or viruses treated with formalin that kills or inactivated microbes by cross-linking their proteins - EXAMPLES: Salk polio vaccine, Influenza vaccine, Rabies vaccine, Hepatitis A •It protects only against one disease DNA vaccines •They work by having human cell use the introduced foreign DNA to make the microbial protein antigen •It would trigger immune response leading to antibody production that would afford the protection against the disease •It is used in making Russian vaccine against COVID-19, Sputnik V Peptide vaccines •Synthetic fragments of antigen •Stable to heat, •Have little unwanted material •Cause minimal side effects

Developing a vaccine to protect people from the common cold has not been possible because:

colds are caused by a large number of immunologically different viruses.

Subunit vaccines

contain purified from pathogen key protein antigens or antigenic fragments - EXAMPLES: Acellular Pertussis vaccine (it is a part of DTaP vaccine), •Toxoids - toxins purified from pathogen that are inactivated but retaining antigenic properties of native toxins. EXAMPLES: Diphtheria and Tetanus toxoids that are part of DTaP vaccine •Polysaccharide vaccines contain polysaccharides purified from capsules. They can not be used in immunization of young children, reserved for immunization of adults only. EXAMPLES: PPSV (pneumococcal polysaccharide vaccine) against Streptococcus pneumoniae -Conjugated vaccines contain polysaccharides linked to proteins, which turns polysaccharides into T-cell dependent antigens. EXAMPLES: Hib vaccine (against Haemophilus influenza serotype B), PCV-7, PCV-13 (pneumococcal conjugated vaccine against 7 or 13 antigens against Streptococcus pneumoniae) •It can protect against several diseases. Recombinant vaccines produced by genetically modified microorganisms - EXAMPLES: Hepatitis B vaccine is produced in yeasts producing part of viral coat proteins

The term "latent" is used to describe some of the HIV virus inside of infected host cells because

double-stranded viral DNA (provirus) is inserted into the host DNA. The term "latent" is used to describe some of the HIV virus inside of infected host cells because double-stranded viral DNA (provirus) is inserted into the host DNA.

The provirus state exists when

double-stranded viral DNA is integrated into host cell chromosome.

The HIV protein that is involved in attachment of the virus to host cells is ______.

gp120

The two viral proteins inserted into the host cell membrane as the virus buds out of the cell are gp41 and ______.

gp120 gp120 and gp41 are inserted into the host cell membrane, creating the spikes of the virus before the core of the virus buds out.

Tubercle

granuloma formed in tuberculosis; they are collections of lymphocytes and macrophages found in chronic inflammatory response, an attempt by the body to wall off and contain persistent organisms and antigens

An AIDS/HIV patient in need of a bone marrow transplant receives one from a donor who is CCR5 negative (lacks CCR5). If the procedure is successful, this would result in the HIV patient producing CCR5-negative white blood cells. This is beneficial to the patient because CCR5

is a co-receptor for HIV, so infection of white blood cells by the virus is impaired.

Herd immunity

is a phenomenon when at least 85% of a population acquires immunity to a disease either through natural immunity or a vaccination. It prevents major outbreaks of the contagious disease as the rest of population is also protected due to interruption of disease transmission.

Individual immunity

is when a particular individual has immunity to a disease. It protects the individual from getting a disease

AIDS

is acquired immunodeficiency syndrome, the last stage of HIV infection

Poliomyelitis (polio)

is acute viral disease transmitted via oral-fecal route: •asymptomatic in 90-95% •mild illness in 4-8% •meningitis in 1-2% •paralysis in 0.5% Poliomyelitis as an example of importance of immunization •Before the vaccines, up to 50,000 polio paralytic cases were reported annually in the USA. •Vaccination of public with Salk inactivated polio vaccine (IPV) in 1954 had reduced number of paralytic polio cases to under 600 in 1962. •Introduction of Sabin attenuated vaccine (OPV) in 1963 further reduced number of paralytic polio cases to 5 in 1973. After 1998, there were no paralytic polio cases reported in the USA. •However, the outbreak of polio in former USSR in 1991-1996 due to the lapse in immunization of general public, indicates that the disease is under control only if there is a herd immunity. •NOTE: Salk polio vaccine protects only against paralytic polio cases •Intestines of immunized by Salk inactivated vaccine (IPV) still can be infected by the virus. Outbreak of poliomyelitis in former USSR in 1991-1996 •This outbreak of polio indicate that the disease still has ability to return. •The outbreaks had occur due to inefficient service in public health (particularly lapse in immunization of infants) on territory of former USSR after breakup. •The magnitude of paralytic polio outbreak was limited to 10-110 cases reported annually in Russia or Tajikistan alone with no cases reported before •The outbreak did not reach larger proportions as the population still had herd immunity against polio due to stringent immunization efforts in previous years.

Antimicrobial drug

is any compound that can stop the growth or kill a microbe Antibiotic is antimicrobial drug produced by bacteria or fungi Any compound that interferes with the growth of microbes within a host

HIV

is human immunodeficiency virus, etiological agent of HIV infection and AIDS

Vaccine

is preparation of a pathogen or its parts used to induce active immunity

Immunodeficiency disorder

is the inability of immune system to mount adequate immune response

Selective toxicity

is the most important characteristic of any antimicrobial drug It is ability of antimicrobial drug to stop the growth or kill a microbe without causing damage to the host (human) •drug's ability to interfere with microbial growth without causing the damage to the patient •It is expressed as therapeutic index •TI = [the lowest concentration toxic to human] / [the lowest concentration toxic to microbe] •the higher therapeutic index, the more selective antibiotic is •EXAMPLE: TI for trimethoprim = 250 mM / 0.005 mM = 50,000

•Streptococcus pyogenes

it is HUMAN PATHOGEN that is not a part of normal flora in humans. Severity of the infection is depending on what set of virulence factors is produced: •Capsule/Biofilm interfere with ingestion by phagocytes and helps microbe survive treatment by antibiotics •Adhesins - M protein acts as adhesin but it also inhibits the activity of C3 convertase, thus preventing activation of compliment system and interfering with attraction of phagocytes to the site of infection. Protein F is fibronectin-binding protein and it is analogous to FnBPA of S. aureus •Protein G binds IgG inverted thus interfering with phagocytosis (prevents ingestion). •Enzymes - Hyaluronidase breaks connections between the cells in human tissue thus increasing microbe invasiveness. Streptokinase - dissolves blood clots thus increasing microbe invasiveness; C5a peptidase digest C5a thus preventing inflammation reaction and attraction of phagocytic cells to site of infection. •Exotoxins - Superantigens (SpeA, SpeC) nonspecifically activate T-helper cells leading to "cytokine storm"; Lipid digesting enzymes; Streptolysin O, Streptolysin S are secretory toxins that form pores in cholesterol-containing membranes (i.e. plasma membrane of human cells), which results in cell lysis. •Due to frequent very serious complications, even mild infection caused by S. pyogenes MUST BE TREATED with antibiotics.

AIDS

lasts 1 months or so, if disease is not treated. •AIDS-specific S&S •More specific S&S •T helper-cells count drops below 200 cells per one ml (microliter) •Pneumocystis pneumonia, •Kaposi's sarcoma, •Thrush (candidiasis) •Increased susceptibility to tuberculosis •NOTE: AIDS patients frequently suffer from virus-induced tumors due to integration of HIV genome into the host cell chromosome, which may result in loss of control of the cell cycle, turning normal cells into cancer ones. •Less specific S&S include •Recurring respiratory infections •Sinusitis - inflammation of nasal sinuses, •Bronchitis - inflammation of bronchi, •Otitis - inflammation of middle ear; •Pharyngitis - inflammation of throat •Moderate and unexplained weight loss •Skin rashes •Prostatitis - inflammation of prostate gland, •B cell lymphomas • •FAILURE TO DESCRIBE THE MORE SPECIFIC and LESS SPECIFIC SINGS & SYMPTOMS WOULD LEAD TO REDUCTION OF POINTS IN FINAL EXAM

Incubation period

lasts 2 to 4 weeks •S&S are absent as HIV load is very low and the virus did not cause any serious damage yet. HIV load is rapidly increasing.

Latency stage

lasts from 2 month to 20 years depending on the status of immune system of infected person. •S&S may include recurring respiratory infections

Acute HIV infection

lasts up to 1 month -liver and spleen enlargement - CNS- malaise, headache, neuropathy -pharyngitis -sores in esophagus -muscle pain -lymph node enlargement - rash -weight loss -stomach upset -fever •More specific S&S include •marked drop (30% or more) in T helper cells count, •thrush (candidiasis) •Less specific S&S are Flu-like: •headache, •muscle pain, •fever, •enlargement of lymph nodes, •nausea and vomiting. •Other S&S include •unexpected weight loss. •pharyngitis, •liver & spleen enlargement, •skin rash •Sores in esophagus •FAILURE TO DESCRIBE MORE SPECIFIC AND LESS SPECIFIC SIGNS & SYMPTOMS WOULD LEAD TO REDUCTION OF POINTS IN FINAL EXAM WOULD

Mucociliary escalator

layer of mucus moved by cilia lining the respiratory tract that traps bacteria and other particles and moves them into the throat

The types of cells infected by HIV are ______ early in the course of an infection and ______ later in the infection cycle.

macrophages; helper T cells

Antigenic shift

major changes in antigenic composition of microbe (particularly in influenza virus) resulting from re-shuffling of nucleic acids during infection of the same host cell by different viral strains

Antigenic drift

minor changes that occur naturally (particularly in influenza virus) in antigens as a result of mutations

Adjuvants

must be used with inactivated vaccines. •The substances that help to induce a better immune response. •The most common one is Alum (salts of Al).

B lymphocytes

often need helper T-cell interaction for activation. B lymphocytes are cells that can be activated by helper T cells to differentiate into antibody-secreting plasma cells.

Attenuated pathogen

pathogen whose virulence is reduced by its specific cultivation. •Elevated temperature used by Robert Koch to grow Vibrio cholerae

Bartonellosis is a bacterial disease that is

potentially very dangerous to AIDS patients or other immunocompromised individuals.

The Hib vaccine (Hib = Haemophilus influenza type b) is specially constructed so that an infant's immune system will mount an immune response against the bacterium's capsule. Based on this information, the vaccine is likely a

protein-polysaccharide conjugate.

Sputum

pus and other material coughed up from the lungs

HIV attaches to host cells by binding to

receptors HIV and other viruses attach to receptors on the surface of the host cell. This binding gives the virus its host and tissue specificity.

The HIV enzyme that makes a double-stranded DNA copy of the viral genome is

reverse transcriptase. This enzyme synthesizes DNA from an RNA template.

Extensively drug-resistant tuberculosis (XDR-TB)

strains of Mycobacterium tuberculosis resistant to the first line anti-TB drugs, isoniazid and rifampicin, and at least 3 of the second-line anti-TB drugs

Inhibition of protein synthesis

streptomycin •Blocks initiation of translation •Class - aminoglycosides. EXAMPLES: of other antibiotics from this class are Gentamicin, Kanamycin •It is bactericidal antibiotic as it irreversibly binding to 30S ribosomal subunit and inhibits initiation of translation. •It is broad-spectrum antibiotic that is effective against Gram-positive, Gram-negative and Acid-fast bacteria. However, it is not effective against Enterococcus and Streptococcus. •Side effects: Extended use may lead to nephrotoxicity. Bacterial resistance: Microbes can produce enzymes that chemically modifies the antibiotic Erythromycin •Blocks translocation of ribosome •Class - macrolides; EXAMPLES: of other antibiotics from this class are Azithromycin, Lincomycin •It is bacteriostatic antibiotic as it reversibly binds to 50S ribosomal subunit and inhibits translocation of ribosome, thus inhibiting the elongation of polypeptide chain. •It is broad-spectrum antibiotic that is effective against Gram-positive and Gram-negative bacteria. Bacterial resistance Tetracycline •Blocks tRNA binding to ribosome •Class - tetracyclines. EXAMPLES: of other antibiotics from this class are Oxycycline, Doxycycline •It is bacteriostatic antibiotic: reversibly binds to 30S ribosomal subunit ,inhibits tRNA binding to ribosome •It is broad-spectrum antibiotic that is effective against Gram-positive and Gram-negative bacteria, not effective against Acid-fast bacteria. •Side effects: Tetracyclines can cause discoloration in teeth when it is used by young children •Bacterial resistance: Microbes reduce drug's uptake or increase the antibiotic excretion. Chloramphenicol •Blocks peptide bond formation •Class - chloramphenicols; •It is bacteriostatic antibiotic that inhibits bacterial growth by reversible binding to 50S ribosomal subunit and blocking peptide bond formation, thus inhibiting the elongation of polypeptide chain. •It is broad-spectrum antibiotic that effective against Gram-positive and Gram-negative bacteria. •Side effects: It is toxic and reserved as the last resort antibiotic. It can cause fatal aplastic anemia, a condition when bone marrow does not produce enough new blood cells of all types to replenish the blood. It also increases the risk of leukemia. •Bacterial resistance: Microbe produce enzyme that acetylates the antibiotic.

Antibiotic

substance produced by a microbe that, in small amounts, inhibits the growth or kills another microbe •Semi-synthetic - is isolated from a microbe and chemically modified •Broad-spectrum antibiotics - are active against wide range of various microbes. EXAMPLES: Tetracycline, Streptomycin are active against Gram positive and Gram negative bacteria. Streptomycin is also effective against acid-fast bacteria. •Narrow spectrum antibiotics - are active against specific group of microbes. EXAMPLES: Penicillin, Erythromycin are active against Gram positive bacteria only

HIV infection progresses to full-blown AIDS when

the number of CD4+ helper T cells in the patient's blood drops to a very low level.

In order to make the second strand of DNA when HIV starts replicating inside of a cell,

the original HIV RNA is broken down and its DNA copy is the template for a second DNA strand. HIV RNA is broken down as it is converted into DNA, leaving a single-stranded DNA template which is used to make the second DNA strand.

A characteristic of Klebsiella pneumonia that differentiates it from other types of pneumonia is ______.

thick, bloody sputum

Granulomas similar to those seen in the disease ______ are formed when Histoplasma infects the lungs.

tuberculosis The granulomas that form with histoplasmosis are similar to those seen in tuberculosis. Sometimes histoplasmosis even causes caseous necrosis.

Retroviruses such as HIV have

two copies of single-stranded RNA

The ELISA test ______.

uses enzymes and substrates. The ELISA test uses an enzyme-linked antibody and substrate to cause a color change to occur.

HIV Routes of transmission

‒Contact with the following infected bodily fluids: §Semen, §Vaginal secretion §Blood §Breast milk ‒Sexual contact, ‒Shared needles, ‒Blood transfusion, ‒Organ transplant, ‒Perinatal transmission §Pregnancy, labor, delivery or breast feeding

Comparison of pathogenesis of Varicella, Rubeola, and Rubella

•All three diseases are starting with infection of upper respiratory tract and replication of these viruses in epithelial cells. •Then all three viruses enter circulatory system - blood (varicella and rubella viruses) and lymph (measles virus). •Varicella (chickenpox) •Varicella-Zoster virus delivered to the skin is lysing the cells causing vesicular skin rush due to inflammation reaction. •Virus enters peripheral neurons causing latent viral infection. •When immunity wanes, varicella virus re-activated causing shingles. •Complications from secondary infections are common. •Virus can cross placenta and cause congenital varicella syndrome ranging from underdeveloped toes and fingers to severe anal and bladder malformation, damage to brain (encephalitis, microcephaly, hydrocephaly), damage to eyes and skin disorders •Rubeola (measles) •Virus delivered to skin resulting in inflammation reaction and development of macular skin rash that lasts for about 1 week. •Complications from secondary infections are common. •Rubella (German measles) •Virus is causing sustained viremia. •Produced antibody form complexes with rubella virus that are deposited in skin and joints leading to faint skin rush that last for 3 days and joint pain lasting for 3 weeks. •If pregnant mother becomes infected, rubella virus is causing congenital rubella syndrome with severe birth defects or stillbirth. Rubeola (measles) •Virus infects mucosa of upper respiratory system and mouth −Virus fuses infected cells into giant multinuclear cells (Koplik spots) •Virus enters lymph system and is spread throughout the body −Infection became systemic •Virus is delivered to the skin and infects keratinocytes −Replicating virus triggers inflammation resulting in skin lesions •COMPLICATIOS: ‒Secondary infections caused mainly by Gram-positive cocci like Staphylococcus aureus Rubella (German measles) •Virus infects epithelial cells of upper respiratory tract •Virus enters blood stream causing sustained viremia −Infection became systemic •Produced antibodies form immune complexes −Antibodies bind to virus in reaction of neutralization −Immune complexes are deposited in the skin and joints −This leads to development of skin rash and joint pain •COMPLICATIONS: ‒Secondary infections (pneumonia); ‒Congenital rubella syndrome with various birth defects

General mechanism of type I allergy development

•Allergy develops only on second or subsequent exposure to allergen •First exposure to allergen leads to sensitization of an individual. •Allergen binds to B cell receptor (with specificity identical to the antibody to be produced by descendants of this cell) •The allergen is taken inside the cell and its fragments exposed on MHCII. •The allergen's fragments on MHCII are recognized by T helper cell that delivers interleukin 4, which leads to activation of the B cell. •During immune response the class switching process occurs where Ig M class antibodies are replaced with the IgE class antibodies •Produced IgE antibody binds to mast cells and basophils, both of whom have IgE receptors exposed on their surfaces. •Mast cells are abundantly present in mucous membranes. •Basophils are present in circulatory system •Second and subsequent exposure to allergen leads to allergic reaction •Allergy reaction may develop only upon second and subsequent exposures to allergen. •Allergen binds to IgE antibody on mast cells or basophils. •If it cross-links at least two molecules of the cell-bound IgE, it triggers massive release of histamine within few seconds leading to development of allergic reaction •Local allergic reaction develops, if mast cells are involved. Examples: hives, asthma. •Systemic allergic reaction develops, if basophils circulating in blood stream are involved. Examples: anaphylaxis

Glossary Lect 11

•Antibiotic-associated diarrhea - it is a complication of taking antimicrobial medications •Bile - it is a fluid produced by the liver that aids in the digestion and absorption of fats •Cirrhosis - it is a damage to the liver that interferes with liver function •Dysentery - it is serious form of diarrhea accompanied by blood, pus, and mucus in the feces •Gastroenteritis - it is acute inflammation of the stomach and intestines characterized by nausea, vomiting, diarrhea, and abdominal pain •Gingivitis - it is inflammation of the gums •Hemolytic uremic syndrome (HUS) - it is serious condition

Attenuated vaccines

•Attenuated vaccine is the weakened but still alive pathogen that can grow. •In healthy individuals, it can not cause a disease. •However, It can cause a disease in individuals with compromised immune system •One injection is usually sufficient to develop strong immunity •Examples: vaccines against most viral infections. •Polio (Sabin); Measles, Mumps, Rubella (MMR); Chickenpox (Varicella-Zoster) •Smallpox (Vaccinia virus)

Mechanism of autoimmune disease development

•Autoimmune disease occurs when immune system attacks self-antigens of the cells and tissues. These attacks kill the cells or damage to the tissues. In some cases, certain types of cells can be wiped out completely. •Autoimmune disease may occur due to several reasons: •imperfect clonal deletion of naïve B-cells or T-cytotoxic cells during maturation of immune system; •productions of cross-reactive antibody due to infections caused by microbes carrying antigens that have high homology to host antigens; •injuries when self-antigens normally hidden become exposed to the immune system.

Firmicutes

•Bacitracin is inhibiting synthesis of bacterial cell wall. It is effective against Gram- positive bacteria. High toxicity limits the use to topical applications. •Polymyxin is causing damage to membrane. Effective against Gram-negative bacteria

Clostridial myonecrosis (Gas Gangrene)

•Before antibiotics discovery, it was common infection in wounded soldiers -It occasionally occurs after surgery, especially in people with underlying diseases Signs & symptoms •They begin abruptly with rapidly increasing pain in wounded area •Increased swelling and bloody fluid leaks from wound -Fluid is often brownish and may appear frothy, due to intense gas production (carbon dioxide & hydrogen) •Skin becomes stretched and mottled with black spots •Patient appears very ill but alert •Delirium and coma occur late in illness and is followed by death Etiological agent Clostridium perfrigens, other clostridia •Gram-positive, obligate anaerobe, endospore-forming non-motile bacillus Virulence factors: •Various proteases and Exotoxins Pathogenesis •Microbe enters via deep puncture, insect bite or wound contaminated with soil Presence of dirt and dead tissue create anaerobic conditions in the wound Microbe would not grow in healthy tissue as it is always well oxygenated Growing pathogen produces α toxin that kills human cells causing tissue necrosis Produced proteases increase the growth and spread of a microbe in tissue Produced CO2 and H2 further increase tissue damage & invasiveness of microbe Pathogenesis •Risk factors: •Long delays in treatment of the wound •Presence of dirt and dead tissue in wound that creates anaerobic conditions •Microbe would not grow in healthy tissue as it is always well oxygenated •Bacteria produce α toxin •It kills human cells by compromising integrity of their plasma membrane •Bacteria produce various enzymes that break down the dead tissues •Collagenase breaks down collagen, the main structural protein in the extracellular space in the various connective tissues in humans and animals. It is the most abundant protein in mammals, making up from 25% to 35% of the whole-body protein content. This enzyme It increases the growth (nutrient availability) and spread of a microbe in human tissue •Hyaluronidase breaks down hyaluronic acid that is distributed widely throughout connective, epithelial, and neural tissues. •As strong fermenter, microbe produces a lot of gas (CO2 and H2) •Gas accumulates in tissue, greatly contributing to spread of bacteria in the tissue Epidemiology Classification: Non-communicable, notifiable disease Reservoir: Soil; Dusty surfaces •Routes of transmission: ‒Deep skin wound; Insect bite •Spores of Clostridium perfringens are also present in human and animal feces •Microbe is present in vaginal tract of up to 9% of healthy women •Gas gangrene of uterus is fairly common after self-induced abortion •However, disease is rarely develops after miscarriage or after childbirth •Disease is developing mainly due to neglected wounds •Disease develops only if deep wounds were contaminated with bacterial endospores and were not appropriately cleaned and treated Prevention Vaccine None •Thorough cleaning of deep wounds ‒To ensure adequate oxygenation level, remove all dead tissue, foreign material Treatment Surgery Prompt removal of affected tissues. Amputation may also be required Antibiotic treatment Penicillin and Erythromycin Hyperbaric oxygen treatment

Conjugation of bacterial polysaccharides with CRM197

•CRM197 is non-toxic genetically modified protein that increases efficiency of immune response to bacterial polysaccharide present in vaccine and conjugated to CRM197

Structure of HIV

•Capsid of HIV •It is built of p24 •contains 2 copies of single stranded RNA(+) genome, •3 viral enzymes: •reverse transcriptase (converts ssRNA to double stranded DNA), •integrase (inserts dsDNA viral genome into the host chromosome), •viral protease (cleaves newly synthesized viral pro-protein into proteins used in virion assembly). •Capsid is surrounded by envelop •Viral envelop •It is stabilized by p17 matrix protein. •The envelop is acquired during assembly of virion at the plasma membrane of infected cell •it has two proteins: •gp120 docking protein that serves viral adhesin. •gp41 transmembrane protein that hold gp120 •Presence of "gp" in the name of protein reflects the facts that these proteins are glycoproteins (chemically modified by sugars) • •FAILURE TO DESCRIBE THE COMPONENTS OF CAPSID AND ENVELOP AND THEIR FUNCTIONS WOULD LEAD TO REDUCTION OF POINTS IN FINAL EXAM

Chimerical antibody versus humanized antibody

•Chimerical antibody is MAb produced in hybridomas derived from genetically modified mice where mouse constant region of antibody is replaced with human one. It causes muted immune response and can be injected into patient more than once. •Humanized antibody is MAB produced in hybridomas derived from GMO mice where mouse constant and some of variable region of antibody are replaced with the human ones. Humanized antibody does not trigger immune response in humans and, therefore, better suited for medical use. Some of them have been approved for the use as immunotoxins in cancer therapy. . •EXAMPLES: •Omalizumab is a recombinant humanized monoclonal antibody that is used to treat Type I allergy reactions. This IgG antibody works by binding to the Fc portion of IgE antibodies, preventing them from binding to mast cells and basophils, and therefore, preventing. •Leronlimab (PRO 140) is recombinant humanized monoclonal antibody directed against CCR5 that is used to prevent entry of HIV in T helper cells

Actinobacteria

•Chloramphenicol is reversibly inhibiting protein synthesis. Bacteriostatic. Effective against both Gram-positive and Gram-negative bacteria. It is used as last resort antibiotic for life-threatening infections due to its high toxicity to humans. •Erythromycin is reversibly inhibiting protein synthesis. Bacteriostatic. Effective against both Gram-positive and Gram-negative bacteria. •Streptomycin is IRREVERSIBLY inhibiting protein synthesis, effectively killing microbes. BACTERICIDAL. Effective against both Gram-positive and Gram-negative bacteria. One of the antibiotics used in combination with others in treatment of tuberculosis. •Tetracycline is reversibly inhibiting protein synthesis. Bacteriostatic. Effective against both Gram positive and Gram-negative bacteria.

DTaP vaccine

•DTaP is inactivated subunit vaccine that contains diphtheria and tetanus toxoids and acellular component of Bordetella pertussis. Previous vaccine, DTwP, had the whole killed cells of B. pertussis. •DTaP vaccine provides protection against diphtheria, tetanus, and pertussis (whooping cough). •It can be used in pregnant women and immunocompromised.

Actinobacteria

•Diphtheroids are similar to Corynebacterium but lack the metachromatic granules Gram-positive bacteria that have high GC-content (50-75%). Some are acid fast bacteria. Cutibacterium (former Propionibacterium) Aerotolerant, slender bacillus slightly bent, non-motile. Forms no endospores Cutibacterium (Propionibacterium) acnes Part of normal flora, slow growing, usually residing in sweat and sebaceous glands Strains causing acne producing few virulence factors - tissue-degrading enzymes and may form biofilms Some strains may even show b-hemolytic activity Responsible for body odor due to breaking down oily components and formation of propionic acid that has strong distinct unpleasant odor. Propionibacterium acnes •Gram-positive, aerotolerant slightly bent bacilli lacking growth arrangements. •It is part of skin normal flora of sebaceous gland rich shoulders and head •Strains causing acne can produce several virulence factors: −Tissue-degrading enzymes (lipases, hyaluronate lyase, proteases) −Hyaluronate lyase is an enzyme that degrades hyaluronan, a component of the extracellular matrix in connective tissue in humans. −Biofilm formation is major virulence factor of P. acnes in implant associated infections −Some strains may even show b-hemolytic activity Corynebacterium Facultative anaerobe, slender bacillus slightly bent, non-motile, Forms no endospores Presence of metachromatic granules Corynebacterium diphtheriae •Part of normal flora •Exhibit palisades growth arrangement •On tellurium-containing blood agar it forms distinctive black colonies Corynebacterium diphtheriae •Gram-positive, catalase positive, non spore-forming, nonmotile, slightly curved bacilli that have palisade (or Chinese letters) growth arrangements •It is still producing some mycolic acid, therefore, can be considered acid fast •Microbe has metachromatic granules that are storing phosphates. •In Albert-Ponder stain, the cell stained by a single dye shows two colors, green and brown (due to pH differences - metachromatic granules have acidic pH, while cytoplasm has neutral pH). •The microbe is part of normal flora and can not penetrate the first line of defense and, thus, always remains on surface of mucous membrane or skin. •It produces diphthin, the protease digesting IgA class antibodies, that enables microbe survive on surface of mucous membrane •Only after lysogenic conversion by beta virus, C. diphtheriae turns pathogenic and produces diphtheria toxin. Diphtheria toxin is class A-B secretory toxin that inhibits protein synthesis in targeted cell.

Type I allergy reaction

•During first exposure to allergen, naïve B cells are activated via T helper cells and are going via clonal expansion. Newly formed plasma cells start producing IgM class antibodies. In process of antibody class switching, the cells switch antibody production from IgM to IgE class antibodies, which are loaded on IgE receptors of mast cells and basophils. The allergic reaction is triggered upon subsequent exposures to the same allergen, when it cross-links at least two molecules of the cell-bound IgE, which triggers massive release of histamine leading to allergic reaction. •Prevention - Desensitization techniques tis used o reduce sensitivity - small quantities of allergen is injected in attempt to force B cells to switch from IgE to IgG production. . •Treatment - Injection of epinephrine (adrenaline) improves passage of airways, increases blood pressure. Intravenous fluids are given to replenish the loss of fluids in circulatory system. Anti-histamines and Steroids - the effectiveness is assumed, not proven. •Omalizumab is a recombinant humanized monoclonal antibody (rhuMAb) that can be administered by intravenous injection to treat astma. This monoclonal IgG antibody bindis to the Fc portion of IgE antibodies, preventing them from binding to mast cells and basophils.

HIV treatment

•Entry inhibitors block access to CCR5 co-receptor or prevent fusion of viral envelope with host cell membrane. ‒EXAMPLES: Leronlimab, Fostemsavir •Reverse transcriptase inhibitors block conversion of viral ssRNA to dsDNA ‒Nucleoside analogs are competitive inhibitors of reverse transcriptase (RT). EXAMPLES: AZT, D4T, 3TC, Tenofovir, Emtricitabine ‒Non-nucleoside inhibitors are non-competitive inhibitors of reverse transcriptase (RT). EXAMPLES: Nevirapine, Delavirdine •Integrase inhibitors block integration of viral genome into host's chromosome and prevent HIV from turning into provirus ‒EXAMPLES: Raltegravir •Protease inhibitors interfere with cleavage of HIV pro-protein into active subunits and, thus, block assembly of new viral particles. ‒EXAMPLES: Saquinavir, Indinavir, Ritonavir Highly Active Anti-Retroviral Therapy (HAART) •It usually consists of 2 nucleoside analogs of RTI and either 1 PI or 1 non-nucleoside RTI Cost and availability of treatment to HIV infected •Globally, less than 50% of HIV infected have access to the treatment •According to article published in New York Times on September 18, 2018: ‒Annual cost of HIV treatment in the USA is $39,000 (~$107 per day) ‒Overall, about $20,000,000,000 are annually spent on HIV treatment in the USA Entry inhibitors •Leronlimab (PRO 140) is humanized monoclonal antibody targeted against the CCR5 thus preventing HIV entry into T helper cells •Fostemsavir (Rukobia) interferes with the interaction of CD4 and gp120 by binding to it, thus preventing entry of HIV into helper cells, macrophages, and dendritic cells. • Cost of HIV treatment in 2018 •According to article published in New York Times on September 18, 2018 https://www.nytimes.com/2018/09/18/opinion/pricing-hiv-drugs-america.html •HIV drugs annual cost is $39,000 in the US or about $107 per day. •Overall, the USA spends about $20 billion a year on HIV drugs.

Pathogenesis 1.Using the graph, describe dynamics and relationship between HIV, T helper cells, macrophages, anti-HIV antibodies, natural killers, normal flora during all four stages of HIV infection 2.Use slide 21 to describe how immune response makes more cells infected.

•FAILURE TO DESCRIBE PATHOGENESIS @ ALL STAGES OF HIV INFECTION WOULD LEAD TO REDUCTION OF POINTS IN FINAL EXAM 1. First stage- T-helper cell count is high, copies of HIV RNA are low, 2. Macrophages as major reservoir of HIV in infected •Anti-HIV antibodies produced during acute HIV infection stage opsonize HIV virions that are recognized and bound by macrophages via Fc receptors. •However, viral envelop blocks the fusion of phagosomes with lysosomes. In some cases, HIV remain in phagosomes & survive for months. In other cases, HIV replicates inside macrophage making it a source of newly produced HIV. •Virions (viral particles) are assembled at plasma (cytoplasmic) membrane and released from the infected cell via budding. CD4 receptor with co-receptor •CD4 (cluster of differentiation 4) is a glycoprotein found on the surface of immune cells such as •T helper cells that are also carrying CXCR4 co-receptor •Monocytes (macrophages and dendritic cells) that are also carrying CCR5 co-receptor involved in binding of HIV Fc receptors •Its name is derived from its binding specificity for a part of an antibody known as the Fc (fragment crystallizable) region. •Fc receptors bind to antibodies that are attached to infected cells or invading pathogens. •Their activity stimulates phagocytic or cytotoxic cells to destroy microbes, or infected cells by antibody-mediated phagocytosis or by antibody-dependent cell-mediated cytotoxicity. •They are present on B lymphocytes, follicular dendritic cells, natural killer cells, macrophages, neutrophils, eosinophils, basophils, human platelets, mast cells

Streptococcus

•Gram-positive aerotolerant (obligate fermenters). •Salt-sensitive; Catalase-negative; Growing as Cocci in chains •S. mutans, S. pneumoniae, S. salivarius, S. viridans they are part of normal flora S. pneumoniae The growth on blood agar. Note the color of medium around colonies •It prefers to grow on mucous membrane of mouth and trachea. •Opportunistic pathogen ‒Capsule is the key virulence factor that inhibit C3b activity it is OPPORTUNISTIC PATHOGEN. However, microbe can be carried asymptomatically. The only known virulence factors produced by S. pneumoniae are •Capsule. Key virulence factor that interferes with phagocytosis via inhibition of C3b activity. •IgA protease, digesting IgA class antibodies •Pneumolysin - pore-forming exotoxin that can interfere with functions of soluble molecules and cells of the immune system. •Microbe can cause infections only if it produces capsule AND it enters lungs, which can occur only if ciliary escalator is non-functional. If capsule is not produced, then strain can not even colonize the host. S. pyogenes The growth on blood agar. Note the color of medium around colonies •It prefers to grow on mucous membrane of mouth and trachea •Pathogen producing various virulence factors & their combinations −See slide notes for details it is HUMAN PATHOGEN that is not a part of normal flora in humans. Severity of the infection is depending on what set of virulence factors is produced: •Capsule/Biofilm interfere with ingestion by phagocytes and helps microbe survive treatment by antibiotics •Adhesins - M protein acts as adhesin but it also inhibits the activity of C3 convertase, thus preventing activation of compliment system and interfering with attraction of phagocytes to the site of infection. Protein F is fibronectin-binding protein and it is analogous to FnBPA of S. aureus •Protein G binds IgG inverted thus interfering with phagocytosis (prevents ingestion). •Enzymes - Hyaluronidase breaks connections between the cells in human tissue thus increasing microbe invasiveness. Streptokinase - dissolves blood clots thus increasing microbe invasiveness; C5a peptidase digest C5a thus preventing inflammation reaction and attraction of phagocytic cells to site of infection. •Exotoxins - Superantigens (SpeA, SpeC) nonspecifically activate T-helper cells leading to "cytokine storm"; Lipid digesting enzymes; Streptolysin O, Sreptolysin S are secretory toxins that form pores in cholesterol-containing membranes (i.e. plasma membrane of human cells), which results in cell lysis. •Due to frequent very serious complications, even mild infection caused by S. pyogenes MUST BE TREATED with antibiotics.

Monitoring progression of HIV infection

•HIV disease progression can be monitored using fluorescence-activated cell sorting by using a fluorescently labeled anti-CD4 antibody to count the number of CD4+ T cells in a patient's blood sample.

HIV replication

•HIV infects CD4-positive cells that carry CCR5 (macrophages, dendric cells) or CXCR4 (T helper cell) co-receptor via interaction of gp120 with CD4/co-receptor complex. •Once in the cell, HIV is uncoated and viral ssRNA(+) is converted to dsDNA by reverse transcriptase. •Then dsDNA forms complex with intergrase, enters nucleus where it is inserted into the host chromosome. Virus may lay dormant or replicate: dsDNA is used to make copies of viral genome that is also used to make viral proteins in cytoplasm. •New HIV virions are assembled at plasma membrane of infected cell and released via budding. •NOTE: AIDS patients frequently suffer from virus-induced tumors due to integration of HIV genome into the host cell chromosome, which may result in loss of control of the cell cycle, turning normal cells into cancer ones. •Watch provided videos or read the textbook. • •FAILURE TO DESCRIBE HIV REPLICATION WOULD LEAD TO REDUCTION OF POINTS IN FINAL EXAM

Genetic analysis via PCR

•If PCR is used, then theoretically a single virion can be detected in the sample. This diagnostic can be used during any stage of HIV infection. The most sensitive method of diagnostics. •PCR (polymerase-chain reaction) allows specific amplification of the gene, generating thousands to millions of copies of a particular DNA sequence •It is highly sensitive but very expensive

MCV-4and MPSV-4 vaccines

•Immunization with these vaccines provides protection against meningitis caused by Neisseria meningitidis •MCV-4 - conjugated vaccines against 4 antigens. Approved for use in young children. •MPSV-4 - polysaccharide vaccine against 4 antigens. Reserved for use in adults

Principles of immunological testing

•Immunological testing takes advantage of specificity of antibody-antigen interactions −It is used in diagnostics of various infectious diseases •If specific antibody is found in a sample, it indicates that patient was exposed to pathogen •If microbial antigen is found in a sample, it indicates that patient is infected with a microbe

Immunotoxins

•Immunotoxins are antibodies conjugated with toxin. •Immunotoxin specifically binds to a particular type of cell (i.e. cancer cell) •Then, it is taken inside the cell (internalized) and toxin kills the targeted cell. •Humanized antibodies are particularly well suited for use as immunotoxins since they do not trigger immune response in humans. •So far, 9 monoclonal antibodies have been approved for cancer therapy

Critical function of lungs is gas exchange

•In alveoli the oxygen delivered by air inspiration is exchanged for carbon dioxide •Any interference with gas exchange (for example - inflammation reaction) may create grave situation and even kill patient.

Autoimmune diseases

•In autoimmune disease immune system attacks self antigens Autoimmune disease may develop due to: −Imperfect clonal deletion of B cells or T cytotoxic cells - see lecture 5/slide 19 −Tissue injury when self antigens, normally hidden, become exposed to immune system −Infections leading to immune response to other antigens that are similar to self antigens Type 1 diabetes mellitus It occurs when immune system attacks the insulin-producing beta cells in the pancreas Rheumatoid arthritis It occurs when immune system attacks cartilage and synovial membrane

Inactivated vaccines

•Inactivated vaccine is a killed pathogen or its parts. •It can not grow or cause a disease in healthy or immunocompromised individuals. •Multiple injections are required with adjuvant to develop strong immunity •Examples: •Against dangerous or latent viruses: Polio (Salk), Hepatitis, Rabies •Against dangerous bacterial infections: Diphtheria, Tetanus, Pertussis (DTaP); Meningitis (MCN-4, MPSV-4, Hib); Pneumonia (PCV-7, PCV-13)

Rubella (German measles)

•Incubation period up to 3 weeks •Faint macular rash appears on face, spreads to the body, fades in 3 days •Swollen lymph nodes behind ears, on neck •Forchheimer's sign in 20% cases −Small red papules on soft palate •Adults have joint pain for 3 weeks •It is also known as three days measles as the rash lasts for 3 days only •It has incubation period of up to 3 weeks •It begins with slight fever and mild cold. •Faint rosy macular rash appears on face, then spreads to rest of body. •Lymph nodes behind ears and on neck become swollen. •The rash disappears within 3 days. •Small red papules develop on soft palate (Forchheimer's sign) develop in 20% of the cases. •Adults are likely to experience joint pain that can last up to 3 weeks

Types of inactivated vaccines

•It also includes adjuvants - the substances that help to induce a better immune response. The most common adjuvant used is Alum - precipitated aluminum salts. Inactivated whole agent vaccines Subunit vaccines Conjugated vaccines

Rubeola (Measles)

•It begins with running nose, cough, red weepy eyes, fever •Macular rash appears on forehead first, then spreads to the body and lasts for about 1 week •Koplik spots appear on mucosa against molars •This disease is also known as hard or red measles. •It begins with running nose, cough, red weepy eyes and fever. •Macular rash appears first on forehead and then spread to rest of body. •Highly specific Koplik spots resembling grain of salt appear on mucous membrane opposite to molars. •The rash disappears in 1 week. •Secondary infections caused by Gram-positive cocci are common

Mechanism of type III allergy

•It develops when IgG class antibodies and soluble foreign antigen form immune complex that is not promptly eliminated and persist in circulatory system for extended period. •Persisting immune complexes activate compliment system causing vasodilation of blood vessels and entrapment of the immune complexes in the walls of blood vessels. •Attracted neutrophils and basophils release proteases causing the damage to the lining of blood vessels. •The damage activates blood clotting mechanism causing disseminated intravascular coagulation, local blockade of blood flow and tissue necrosis. . •Examples: glomerulonephritis, disseminated intravascular coagulation, Arthus reaction, Serum sickness.

Adverse effects

•It includes possible side-effects resulting for antimicrobial medication use. •EXAMPLES: •Allergic reactions - allergy to penicillin (anaphylaxis - see lecture 9) •Toxic effects - chloramphenicol may cause fatal aplastic anemia, a condition when body can not produce blood cells •Suppression of normal flora - Antibiotic-associated colitis caused by Clostridium difficile

Antimicrobial action

•It includes whether the drug kills microbe or just inhibit the growth. It also includes the drug's targets in the microbial cell. •Bacteriostatic antimicrobial medication - see slide notes to slide 14 •Bactericidal antimicrobial medication - see slide notes to slide 14 •Drug targets in microbe - Cell wall; Protein synthesis (ribosomes); DNA synthesis (DNA polymerase)

Virulence factors of Streptococcus pyogenes.

•It is HUMAN PATHOGEN that is not a part of normal flora in humans. •Severity of the infection caused is depending on what set of virulence factors is produced: •Capsule/Biofilm interfere with ingestion by phagocytes and helps microbe survive treatment by antibiotics •Adhesins - M protein acts as adhesin but also inhibit the activity of C3 convertase, thus preventing activation of compliment system and interfering with attraction of phagocytes to the site of infection. Protein F is fibronectin-binding protein and it is analogous to FnBPA of S. aureus •Protein G binds IgG inverted thus interfering with phagocytosis (prevents ingestion). •Enzymes - Hyaluronidase breaks connections between the cells in human tissue thus increasing microbe invasiveness. Streptokinase - dissolves blood clots thus increasing microbe invasiveness; C5a peptidase digest C5a thus preventing inflammation reaction and attraction of phagocytic cells to site of infection. Exotoxins - Superantigens (SpeA, SpeC) nonspecifically activate T-helper cells leading to "cytokine storm"; Lipid digesting enzymes; Streptolysin O, Sreptolysin S are secretory toxins that form

Virulence factors of Staphylococcus aureus

•It is OPPORTUNISTIC PATHOGEN that is part of normal flora in humans. •Still, various strains of S. aureus can cause various infections in humans depending on what virulence factors are produced: •Capsule/Biofilm interfere with ingestion by phagocytes and helps microbe survive treatment by antibiotics •Adhesins - Clumping factor A binds to fibrin, fibrinogen, plastic devices; FnBPA (fibronectin-binding protein A) binds to acellular tissue substances and plastic devices. •Protein A binds IgG inverted thus interfering with phagocytosis (prevents ingestion) •Enzymes - penicillases and b-lactamases - digest penicillins and b-lactam antibiotics, Catalase - inactivated hydrogen peroxide produced by attacking macrophages; Coagulase - deposit human proteins on bacterial cell and, thus interfering with phagocytosis. It is found in the most virulent strains. Hyaluronidase - breaks connections between the cells in human tissue thus increasing microbe invasiveness. Staphylokinase - dissolves blood clots thus increasing microbe invasiveness •Exotoxins - Superantigen (TSST-1) nonspecifically activates T-helper cells resulting in "cytokine storm". Exfoliative toxin - protease digesting desmoglein I that holds keratinocytes (skin cells) together; a-, b- toxins - membrane-disturbing toxins (pore-forming and lipid-digesting, respectively); Leukocidin is secretory toxin that kills phagocytes by forming pores in their plasma (cytoplasmic) membrane. •Penicillin-binding protein 2a - does not bind penicillin, resulting in bacterial resistance to penicillin. •Staphyloxantin inactivates hydrogen peroxide produced by attacking macrophages

Vacutainer

•It is a device used to collect the blood and isolate antiserum •It is a test tube with negative pressure and closed with rubber stopper. •The test tube has a gel that allows blood cells to go through when test tube is subjected to centrifugation, thus separating the antibody-containing liquid phase (plasma) of blood from blood cells.

Pneumocystis pneumonia (PCP)

•It is a form of pneumonia, caused by the yeast-like fungus Pneumocystis jirovecii. •Pneumocystis pneumonia is not commonly found in the lungs of healthy people, but, •Fungus can cause a lung infection in people with a weak immune system. •Pneumocystis pneumonia is specifically present in patients undergoing chemotherapy for cancer, with HIV/AIDS, and those who use immuno-suppressants. It is caused by a yeast Pneumocystis jiroveci that produce cysts resembling crushed ping-ping balls that can be stained by toluidine blue. On X-ray it shows the presence of characteristic increased opacity (area of whitish dots) in lower lungs on both sides (marked by red arrows)

Pharmacokinetics of antimicrobial medication

•It is concerned with absorption, tissue distribution and stability of the drug in human body. •Route of administration - If drug is unstable at acidic pH and it is destroyed in stomach, then it must be administered intravenously or intramuscularly. EXAMPLES: Penicillin G is sensitive to acid and cannot be taken orally or it must be taken along with antacid, while Penicillin V is not sensitive to acid and can be taken orally. •Tissue distribution of the drug in the body as it may differ from one tissues to another. EXAMPLE: Nitrofurantoin is concentrated in urine only, therefore, it is used only in treatment of urogenital infections. •Half-life of drug is time required for body to eliminate 50% of drug original dose. Half-life dictates the frequency of drug administration. Patients with damaged liver or kidney tend to excrete drugs slowly. EXAMPLE: Penicillin G

Statistical data for HIV cases reported globally

•It is a pandemic disease with about 37 million HIV-infected world-wide. •70% of HIV-infected are living in Africa •9% of HIV-infected are living in North and South America. •The highest level of HIV-infected among teenagers reported in India, South Africa, Kenya, Nigeria (over 100,000 cases in each). •The USA has between 20,000 and 50,000 HIV-infected teenagers. •The level of HIV-infection much lower in Canada (under 1,000). •Predominant routes of HIV transmission world-wide is as following: •#1 heterosexual; •#2 homosexual; •#3 injected drug use HIV cases among teenagers (ages 10-19) reported globally •over 100,000 HIV-infected teenagers in India, South Africa, Kenya, or Nigeria •20,000 to 50,000 HIV-infected teenagers in USA, Brazil or Malaysia •Less than 1,000 HIV-infected teenagers in Canada, Australia or Northern Europe Statistical data for the USA •About 38,000 of new HIV infections reported annually and it is declining. •65% new infections are due to male-to-male homosexual contacts; •26% are due to heterosexual contact, •7% are due to injected drug use. •Highest HIV incidence is in Blacks, Lowest incidence is in Asians. •The states with highest number of new HIV cases are: Florida and California (12% each), Texas (11%), New York and Georgia (7% each). •52% of new HIV infections are reported among 20-34 years old. •FAILURE TO DESCRIBE THE WORLD-WIDE HIV STATISTICS WOULD LEAD TO REDUCTION OF POINTS IN FINAL EXAM

Adjuvant

•It is a substance that increases the immune response to antigen. Alum is most common adjuvant used.

Kaposi's sarcoma

•It is a tumor caused by infection with human herpesvirus 8 (HHV8), also known as Kaposi sarcoma-associated herpesvirus (KSHV) or KS agent. •It is a systemic disease that can manifest with cutaneous lesions with or without internal lesions. •The AIDS-related KS lesions often rapidly progress to plaques and nodules affecting the upper trunk, face, and oral mucosa. Purplish nodules appear on the skin, Infection may also affect mouth, lungs, gastro-intestinal tract

Spectrum of activity of antimicrobial medications

•It is ability of antimicrobial medication to affect the growth of a range of microbes •Broad-spectrum drugs - see slide notes to slide 14 •Narrow-spectrum drugs - see slide notes to slide 14

Smallpox

•It is an acute infectious and contagious disease of humans, caused by either of two virus variants named Variola major and Variola minor. •Variola is a derivative of the Latin varius, meaning "spotted", or varus, meaning "pimple". •Smallpox localizes in small blood vessels of the skin and in the mouth and throat. •In the skin, this leads to characteristic rash, and later to pus-filled pustules mainly localized on limbs and head. •Variola major produces a more serious disease and has an overall mortality rate of 30-35%, while Variola minor causes a milder form of disease with mortality rate about 1% of infected. •Vaccine against smallpox is based on Vaccinia virus, the microbe that infects the cows causing cowpox but it does not cause disease in humans. •Vaccinia virus is closely related to Variola virus and it has proteins with antigenic properties similar to Variola virus •Therefore, antibody produced against Vaccinia virus are also protective against smallpox.

Immunoassay in detection of HIV infection

•It is an in vitro test in which known antibodies or antigens are used to detect or quantify given antibodies / antigens •ELISA (Enzyme-Linked Immunosorbent Assay) test •It is used in initial test to diagnose HIV to detect antibody against HIV •It is a colorimetric assay that is used to detect enzyme-labeled antibodies bound to antigens: •Human blood is added to antigen-coated well of microtiter plate & incubated to allow the binding. Then, plate is rinsed to remove all unbound material •Secondary enzyme-tagged antibody against human antibody Fc domain is added •After rinsing, a substrate for enzyme linked to secondary antibody is added •Development of reaction (color change) indicates that sample is HIV-positive •This is fast but not 100% accurate method •The positive results must be confirmed by other methods. •It can be used only when titer (concentration) of antibody against HIV in the blood is high enough. •Western blot •It is used to confirm positive results of ELISA and it detects the presence of HIV antigen. •It is more time-consuming but more accurate method: •Proteins in sample being tested are separated by SDS gel electrophoresis according to their sizes. •Proteins are transferred on to the membrane via blotting •Membrane is incubated with anti-HIV antibodies, followed by secondary antibody directed against human antibody and tagged by one of the following - radioactivity, enzyme or fluorescent dye •Specific signal is developed

General mechanism of type II allergy

•It is antibody-dependent cytotoxicity that results from production of IgG and IgM antibodies binding to the surface of the self-cells. That is why it is antibody-dependent. •Sticking out Fc domains ("tails") of antibodies bound to the self-cells are triggering the activation of compliment system via classical pathway and an attack by natural killers. All that leads to the death of self-cell. That is why it is cytotoxicity. •Normally this mechanism is used by immune system to kill virus-infected and cancerous cells. However, in certain cases it can lead to allergy reaction. •Examples: transfusion reaction, hemolytic disease of newborn.

Type I allergy

•It is called immediate IgE-mediated allergy because it often develops in under one hour and it involves class IgE antibodies present on surface of basophils or mast cells •Type I allergy occurs in 20-30% of population who are genetically predisposed.

Mechanism of type 1 diabetes mellitus development

•It is caused by imperfect clonal deletion of T cytotoxic cells that attack and kill in pancreas the insulin-producing beta cells. •Insulin is required for exposure of glucose transport protein, GLUT4, on surface of human cells and glucose intake. In the absence of insulin GLUT4 is hidden and human cells are starving even in the presence of glucose. •The following signs and symptoms set in: excessive urination, increased thirst, dry mouth, increased hunger, fatigue, weight loss, premature death. Affected individuals are requiring regular insulin injections for the rest of life.

Oral thrush

•It is caused by overgrowth of Candida albicans, a type of yeast that is commonly referred to as a dimorphic fungus since it grows both as yeast and filamentous cells. •It is a common in human gut flora of up to 60% of healthy adults and does not survive outside mammalian hosts and causes problems in immunocompromised individuals. •Overgrowth of the fungus results in candidiasis (called oral thrush if it happens on mucous membrane in the mouth). Candidiasis is often observed in HIV-infected patients.

History of HIV/AIDS

•It is estimated that virus may have crossed from chimpanzee to humans in Western Africa in late XIX or beginning of XX century •probably due to hunting primates for meat (bush-meat) •Until 1950-ties, AIDS was endemic disease limited to certain areas on African continent •In 1950-ties the spread of the disease was facilitated by human migration and urbanization •Retroactive epidemiological studies established the oldest known AIDS case •Anti-HIV antibodies were found in blood samples of patient who has died in 1959 in Congo •Development of modern transportation and unsafe sex practice further helped to spread HIV •First Westerner known to die from AIDS was Norwegian sailor who has died in 1976 •FAILURE TO DESCRIBE THE ROUTES OF TRANSMISSION AND HIV STATISTICS (WORLD-WIDE and USA) WOULD LEAD TO REDUCTION OF POINTS IN FINAL EXAM

Impetigo

•It is exogenous skin disease ‒microbes are entering via damaged skin Signs & symptoms Bullous impetigo •Painless bulla on trunk, arms, legs. •Mainly affect kids under two years of age. Impetigo contagiosa •Affects deeper skin layer. •Produces flu-like symptoms: ‒fatigue, headaches, vomiting Ecthyma •Painful pus-filled sores turned in to ulcers. •Swollen lymph nodes next to affected area •Bullous impetigo - Affects mainly infants and children under 2 years. •It is painless bulla on the trunk, arms and legs. •Skin around bulla is red and itchy but not sore. •If bulla breaks, it is covered by yellowish crust. •May last longer than sores from other types of impetigo. •Impetigo contagiosa - Affects deeper layers of the skin •Discrete, thin-walled pustule that rupture, releasing pus that produces crust. •It causes flu-like symptoms: Fatigue, Weakness of muscles, Headaches, Vomiting. •Ecthyma •Painful fluid/pus-filled sores turning to deep ulcers •Swollen lymph nodes next to the affected area •Hard, thick, gray-yellow crust is covering the sores •Little holes the size of pinheads to the size of pennies appear after crust recedes leading to scars. Etiological agents Staphylococcus aureus •Gram-positive cocci in clusters ‒Halophiles; Mannitol & Catalase positive •Facultative anaerobes Streptococcus pyogenes •Gram-positive cocci in chains •Salt-sensitive; Mannitol & Catalase negative •Aerotolerant •Virulence factors: numerous Pathogenicity •Pathogen enters the host via minor breaks in the skin ‒Virulence factors like proteases, hyaluronidase increase the invasiveness of Staphylococcus aureus invade deep layers of the tissue •Contact of bacterial cells and host tissue results in local inflammation reaction that leads to development of skin lesions Epidemiology •Reservoir: ‒Humans •Routes of transmission: ‒Enters via damaged skin ‒Respiratory droplets ‒Direct contacts (hand shakes) ‒Indirect contacts (fomites) •Classification: ‒Contagious, Non-notifiable disease •Statistics: ‒World-wide data - disease affects over 160,000,000 children annually §Prevalent among 2 to 6 year-old children •Predisposing factors: −Young age; Scratching; Playing close contact sports; Tropical climate; Immunodeficiency Prevention •Good hygiene ‒Keep the skin clean ‒Avoid contacts with infected ‒Wounds must be treated and covered Treatment •Antibiotic treatment −Erythromycin, b-Lactams •Hydrogen peroxide treatment •Antibacterial soaps & creams Capsule - interferes with phagocytosis and immune response. •Capsule of Streptococcus pyogenes is made of hyaluronic acid and, therefore, it has very low antigenicity Antibody-binding proteins - they bind antibodies by their Fc domains ("tails"), thus interfering with phagocytosis •Protein A - located on cell wall of S. aureus interfere with immune response. Protein A also provides bacterial cell protection against invasion by certain bacteriophages •Protein G is found in Streptococcus pyogenes and interfere with immune response similarly to protein A of S. aureus Adhesins - are proteins that allow pathogens to bind to the host •Clumping factor A - adhesin found in Staphylococcus aureus •FnBPA (fibronectin-binding protein A) is another adhesin of S. aureus that enables microbe to bind to connective tissue in humans •Protein M - facilitate binding of S. pyogenes to host cells/tissue •It also interferes with activation of compliment system by inhibition of C3 convertase that splits C3 into C3a and C3b •Antibodies against protein M are cross-reacting with antigens found in human heart muscle •Protein F - facilitate binding of S. pyogenes to host cells/tissue. It has multiple serotypes and determines type of tissue that strain can infect. It is analogous to FnBPA of S. aureus Proteases - tissue-destroying enzymes that greatly increase invasiveness of pathogens •lipases •proteases •hyaluronidases

RhoGAM®

•It is human immune globulin is a prescription medicine given by intramuscular injection that is used to prevent Rh immunization, a condition in which an individual with Rh-negative blood develops antibodies after exposure to Rh-positive blood. •It is used: •After delivery of a Rh-positive baby •Routine prevention of Rh immunization at 26 to 28 weeks of pregnancy. •Maternal or fetal bleeding during pregnancy from certain conditions. •Actual or threatened pregnancy loss at any stage. •Ectopic pregnancy (pregnancy in which the fertilized egg implants outside the uterus). •http://www.rhogam.com/patients/you-re-pregnant-and-you-re-rh-negative/

Streptococcal pharyngitis (Strep throat)

•It is inflammation of the pharynx resulting in sore throat. •It can be caused by various bacteria and viruses Signs & symptoms Sore throat High fever (above 38oC or 100oF) Enlarged reddish tonsils with pus patches Enlarged lymph nodes in the neck Signs and symptoms may also include: Headache, nausea and vomiting, Myalgia (muscle pain) Rash on soft palate - palatal petechiae Etiological Agent Streptococcus pyogenes, Aerotolerant Gram-positive cocci in chains. Virulence factors: Numerous. For details see slide 8 of this lecture Pathogenesis •Streptococcus pyogenes binds to epithelial cells in pharynx by using Proteins F and M protein as adhesins −M protein (over 80 known serotypes) also inhibits activity of C3 convertase •During colonization, microbe produces enzymes: Proteases, Hyaluronidase, Streptokinase that increase invasiveness of pathogen. •Efficiency of immune response is reduced by Capsule, protein G, C5a peptidase •Continuous contact of pathogen with human tissue results in intense inflammation ‒That leads to development of signs and symptoms of the disease ‒Up to 12% of people are carrying Streptococcus pyogenes asymptomatically •Complications −Serious complications develop if infection is left untreated. −They include: Retropharyngeal abscesses; Rheumatic fever; Acute glomerulonephritis Epidemiology •Reservoir: ‒Humans only •Routes of transmission: ‒Respiratory droplets ‒Direct (Hand shakes) Indirect contacts (Fomites) •Classification: ‒Сontagious, Non-Notifiable disease •Statistics: ‒World-wide data - Number of cases unknown §Incidence peaks in winter & spring §Most cases occur among school children ‒US data - up to 4,000,000 cases annually §S. pyogenes survives on tooth brush for 15 days Antigenic variations in protein M define what type of disease would be caused by a strain •Streptokinase is an enzyme that activates human plasminogen resulting in formation of plasmin, the protein that can dissolve blood clots and can activate collagenases •Thus, streptokinase is facilitating the spread of bacterium in the infected body •Hyaluronidase is an enzyme that can digest hyaluronic acid, thus increasing tissue permeability for the microbe Retropharyngean abscesses •It is infection of deep tissue on the back of pharynx •Sign and symptoms •Stiff and painful neck, difficulties of swallowing, fever, enlarged lymph nodes in neck. Rheumatic fever •It is a complication is caused by anti-M-protein antibody cross-reactivity that can involve heart, joints, skin, or brain. It occurs 2-3 weeks past infection, typically in children 5 - 17 y. old •Signs and symptoms •Migratory polyarthritis - from legs upwards; •Corditis - inflammation of heart muscle leading to congestive heart failure, shortness of breath, heart murmur •Erythema marginatum - long lasting rash on trunk and/or arms Acute glomerulonephritis (post-infection post-streptococcal glomerulonephritis) •It is a disorder of small vessels in the kidneys caused by infections, particularly streptococcal infections of skin (impetigo) or streptococcal pharyngitis (very rare). •It is type III allergy reaction, when immune complexes are trapped in capillaries. •Signs and symptoms •Hematuria is presence of the blood in urine •Oliguria - is when urine output reduced to 400 ml/day (normally it should be 600 to 2500) •Hypertension, •Acute renal necrosis due to capillary necrosis or capillary thrombosis Prevention •Quarantine ‒For those who are infected. They must stay @ home Vaccine Not available Due to wide antigenic variability of protein M Good hygiene Avoid crowds and crowded places Adequate ventilation of buildings reduces the rate of transmission Tonsillectomy in patients with frequent throat infections Treatment •To relieve pain Paracetamol (acetaminophen) •Before antibiotic treatment ‒Pharyngitis with S&S similar to strep throat can also be caused by viruses §Therefore, streptococcal infection must be confirmed ‒Confirmation by bacterial cultivation or ID-ing by Rapid Antigen Detection Test §Rapid diagnostics may also use DNA probe testing •Antibiotic treatment of confirmed streptococcal cases Treatment reduces the risks of complications & spread of the infection Penicillin or Cephalosporins. If sensitive to b-lactams, then Erythromycin

Asthma

•It is local allergy involving mucous membrane of respiratory airways •It is characterized by reversible airflow obstruction & bronchospasm.

Pseudomonas aeruginosa Infections

•It is mainly secondary and nosocomial infections of ‒skin, external ear, eye, lungs •Infections can also be contracted in swimming pools and hot tubs Signs & symptoms •Skin lesions, Chills, Fever, •Shock, caused by bacteremia •Change in tissue color -P. aeruginosa produces water-soluble pigments: pyocyanin (blue) and pyoverdine (yellow) Etiological agent Pseudomonas aeruginosa •Gram-negative, •Motile bacillus •Facultative anaerobe •Virulence factors: ‒Various hydrolytic enzymes §That enables microbe to survive in water condensate, disinfectants, human body ‒Endotoxin ‒Exotoxins §Exotoxin A, Exoenzyme S, Phospholipase C ‒Pigments §Pyocyanin forms biofilm §Pyoverdine functions as siderophore P. aeruginosa is an opportunistic pathogen •Exotoxins: •Exotoxin A is delivered via type III secretion system. It stops protein synthesis, which is causing the death of host cells •Exoenzyme S is produced by majority of strains. It interferes with phagocytosis. •Phospholipase C is an enzyme that causes the damage to plasma membrane of host cells by digesting lecithin. It leads to death of host cells •Enzymes: •Collagenase is an enzyme digesting collagen in human tissues. This helps microbe to spread in to deeper layers of human tissue. •Elastase is an enzyme digesting elastin in human tissues. This helps microbe to spread in human tissues. Pathogenesis •P. aeruginosa is causing mainly secondary and nosocomial infections •Continuous contact of bacteria and human tissue results in inflammation reaction ‒Produced enzymes, like proteases, cause additional damage and delay the healing •Produced toxins increase the microbe's invasiveness -Exoenzyme S, Exotoxin A, Phospholipase C •Formation of biofilm considerably complicates antibacterial treatment •COMPLICATIONS: −if it enters bloodstream, it can cause infections of heart, bones, kidneys, or septic shock Epidemiology •Classification: ‒Communicable disease •Reservoir: ‒Environment, Humans •Routes of transmission: ‒Vehicles: §water, soil, §fomites •Microbe can persist in standing or distilled water •It also can contaminate: -Chlorinated swimming pools; Hot tubs -Soaps; Eye drops; Ointments; Disinfectants; •P. aeruginosa is ubiquitous and can easily enter hospitals on shoes, flowers, ornamental plants Exoenzyme S of P. aeruginosa https://www.ncbi.nlm.nih.gov/pmc/articles/PMC187317/ •It is a type III secretion effector which includes both a GTPase-activating protein and an ADP-ribosyltransferase (ADPRT) activity. •It interferes with phagocytic activity of macrophages Commonly acquired infections include •Rash and external ear infections •Obtained from contaminated swimming pools and hot tubs •Infection of foot bones •Eye infections •Heart valve infections •Lung biofilms Nosocomial infections include •Lung infections •Burn infections Prevention •Elimination of bacterial sources •Prompt wound care Treatment •Antibiotic treatment -Imipenem, Gentamicin, Ciprofloxacin •Antibacterial silver cream •Broad-spectrum antibiotics administered as ointments •However, many bacterial strains are multi-drug resistant •In case of bacteremia, medications must be administered intravenously and at much higher doses

PCV-13 vaccine

•It is pneumococcal conjugated vaccine against 13 antigens that was approved in 2009 for immunization of adults only. •Replacement of PCV-7 for PCV-13 in immunization of adults led to decline in prevalence of invasive pneumococcal disease not only adults but also among young children who were still immunized by PCV-7

PCV-7 vaccine

•It is pneumococcal conjugated vaccine against 7 antigens that was approved n 1997 for immunization of children and adults. •Its introduction resulted in 4-fold decline in prevalence (# cases reported for 100,000 people) of invasive pneumococcal disease among young children. •The use of this vaccine in immunization of adults resulted in 30% decline in prevalence of invasive pneumococcal disease among old adults

Vaccine against cancer

•It is practically impossible to develop universal vaccine against all types of cancer •Each type of cancer caused by different factors and affects specific type of cell, tissue.

Anaphylaxis

•It is systemic allergy that involves basophils •As allergen enters the blood stream, histamine is released from basophils throughout entire body. •Most cases are associated with peanuts, bee stings, and penicillin injections.

Rheumatoid arthritis

•It is systemic disease in which immune response (antibodies and cellular components) target cartilage and synovial membrane of the joints in wrists, palms, knees, ankles and feet. It results in eventual immobilization of affected person.

Immunization (vaccination)

•It protects via individual immunity & also herd immunity (when 85% or more of population is immunized).

Antimicrobial action

•It refers to cellular processes or structures that drug is targeting

Spectrum of activity of antimicrobial medications

•It refers to range of microbes against which antibiotic is effective •Broad and narrow spectrum drugs - for details, see slide notes to slide 14 •It is checked by Kirby-Bauer (disk-diffusion) method •For details, see slide 25 of lecture 2 •The bigger zone of inhibition, the more effective drug is. However, size of inhibition zone is also influenced by the drug's size, stability and concentration •The size of the zone is influenced by the drug's molecular weight (size), stability, and concentration.

Penicillin

•It was discovered by Alexander Fleming (Scotland) in 1928, while he was working with pure cultures of Staphylococcus aureus. •One day he noticed that bacterial growth n Petri dish was partially suppressed in close proximity to colonies of a mold contaminant, Penicillium notatum (chrysogenum). •In 1945, he shared Nobel Prize with Florey and Chain, who purified the drug. •Antibiotic inhibits the synthesis of bacterial cell wall and is effective mainly against Gram positive bacteria. It is also effective against Neisseria, Gram negative bacteria. •Natural penicillins are isolated from fungi: •Penicillin G is sensitive to acidic environment of stomach and, therefore, must be administered intramuscularly. •Penicillin V, is acid-resistant and, therefore, can be taken orally. •Semi-synthetic penicillins are isolated from fungi and then chemically modified that led to new properties of penicillins: •Ampicillin has broader antimicrobial spectrum •Methicillin is resistant to inactivation by penicillinase, bacterial enzyme that can digest natural penicillins.

Streptomycin

•It was discovered by Selman Waksman (USA) in 1943, while he was working at Rutgers University with bacterial flora of soil. •Antibiotic was isolated from actinobacterium Streptomyces griseus found in soil. •Antibiotic irreversibly inhibits protein synthesis. •It is antibiotic of choice in treatment of tuberculosis.

Hives

•Local allergy involving skin reaction. It occur in people with food allergy when they ingest food. •Allergen is absorbed from intestines into bloodstream. It is delivered to the skin, where it binds to IgE on mast cells, causing degranulation and inflammation reaction leading to skin rash.

MMR vaccine

•MMR contains three attenuated live viruses: measles, mumps, and rubella and provides protection against corresponding diseases. •The vaccine can not be used in pregnant women due to high risk of rubella congenital syndrome.

Production of monoclonal antibody

•Mouse is injected with antigen •Spleen is taken from immunized animal and the cells are collected •Spleen cells (including activated B cells) are fused with myeloma cells (cancerous B cells isolated from mice and cultured in vitro) •The cells are placed in multi-well plates (1 cell per well) and is grown in selective medium that allows only hybrid cells to grow. •Hybridomas producing antibodies are selected and tested for antibody production. •Selected clone is expanded and used to produce monoclonal antibody

Secretions of mucous membrane of respiratory system:

•Mucus - captures microbes entering with air; •Ig A promote phagocytosis; •Lysozyme is an enzyme that can digest bacterial cell wall; •The surface of mucous membrane is scouted by wandering and alveolar microphages

Principles of immunization

•Naturally acquired immunity is acquisition of adaptive immunity via natural events •Artificially acquired immunity is acquisition of adaptive immunity via human acts

Vaccine against influenza (flu)

•New vaccine is required due to high mutation rate of influenza virus

Vaccine against HIV

•No vaccines effective against HIV are developed yet.

Blood types

•One of the red blood cell's surface proteins can be chemically modified by sugar type A, sugar type B or not modified at all. It is defined by genotype of individual. •Blood types O, A, B, or AB reflect no modification of the protein, modifications of the protein with type A sugar, with type B sugar, or with both sugar types, respectively. •As fetus develops, immune system kills off naïve B cells that can produce antibody against self-antigens present on red blood cells. However, naïve B cells capable of producing antibody against surface antigens of RBC not present in fetus survive clonal deletion.

Fungi

•Penicillins are inhibiting the synthesis of bacterial cell wall. Diverse family of antibiotics. Penicillins are more effective against Gram-positive bacteria and are less effective against Gram-negative bacteria, as it can not penetrate their outer membrane. However, it can have effect only on actively growing microbes. •Cephalosporins are inhibiting the synthesis of bacterial cell wall. However, it can have effect only on actively growing microbes. Cephalosporins are effective against both Gram-positive and Gram-negative bacteria, as it can cross outer membrane of later bacteria. However, they are less effective on Gram-positive bacteria as tend to have low affinity to penicillin-binding proteins of these bacteria

Bacterial pneumonia

•Pneumonia is resulting from infection and inflammation of lung tissue −Among infectious diseases, it is the major killer of general public in any country •This disease can be caused by bacteria, viruses or even fungi −We will focus on 3 bacterial pneumonia: §Pneumococcal pneumonia caused by Streptococcus pneumoniae §Klebsiella pneumonia caused by Klebsiella pneumoniae §Mycoplasmal pneumonia caused by Mycoplasma pneumoniae Signs & Symptoms Common Signs and Symptoms •It starts with Runny nose; Cough; High fever •Upper respiratory system quickly becomes congested •Shallow breathing; Chest pain; Headache Signs & Symptoms specific to Pneumococcal pneumonia •None •All Signs and Symptoms abate within 5 - 7 days. Signs & Symptoms specific to Klebsiella pneumonia •Red gelatinous sputum •All Signs and Symptoms are very severe Signs & Symptoms specific to Mycoplasmal pneumonia •Mucoid sputum; Dry cough •All Signs and Symptoms are very mild and can be missed Etiological agents Streptococcus pneumoniae •Gram-positive •Aerotolerant •lancet-shaped diplococci arranged into chains •Virulence factors: ‒Capsule §a key factor that interferes with C3b ‒Adhesins, ‒IgA protease, −Pneumolysin §a pore-forming toxin Klebsiella pneumoniae •Gram-negative •Facultative anaerobe, •Non-motile bacilli with no arrangement •Virulence factors: ‒Capsule, −Adhesins, −Endotoxin, −Siderophores Mycoplasma pneumoniae •No cell wall •Obligate aerobe, •Motile pleomorphic bacteria, no arrangement •Virulence factors: −Adhesin P1 organized into "TIP-structure" Klebsiella pneumoniae •home page on CDC.com http://www.cdc.gov/HAI/organisms/klebsiella/klebsiella.html •Pan-Resistant New Delhi Metallo-Beta-Lactamase-Producing Klebsiella pneumoniae - Washoe County, Nevada, 2016 - MMWR - January 13, 2017 / 66(1);33 - https://www.cdc.gov/mmwr/volumes/66/wr/mm6601a7.htm •On August 25, 2016, the Washoe County Health District in Reno, Nevada, was notified of a patient at an acute care hospital with carbapenem-resistant Enterobacteriaceae (CRE) that was resistant to all available antimicrobial drugs. •The specific CRE, Klebsiella pneumoniae, was isolated from a wound specimen collected on August 19, 2016. •After CRE was identified, the patient was placed in a single room under contact precautions. •Hospital Outbreak of Carbapenem-Resistant Klebsiella pneumoniae Producing New Delhi Metallo-Beta-Lactamase - Denver, Colorado, 2012 - MMWR - February 15, 2013 / 62(06);108 https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6206a5.htm Mycoplasma pneumoniae •home page on CDC.com: http://www.cdc.gov/pneumonia/atypical/mycoplasma/ •Mycoplasma are closely related to genus Clostridium as judged by 16S ribosomal RNA homology •During evolution, mycoplasmas have lost large chunk of its genome, including genes involved in cell wall biosynthesis •Their plasma membrane is reinforced by cholesterol. Pathogenesis Pneumonias are inflammatory disease of the lung in which the fluid accumulated and fills the alveoli Pneumococcal pneumonia •It occurs only if strain is capsulated •After reaching lung alveoli, microbe is causing inflammation reaction −Phagocytosis is fend off by capsule, but no major damage done to lung tissue •COMPLICATIONS: develop if microbe enters blood stream, −Streptococcus pneumoniae may cause Septicemia; Endocarditis; Meningitis Klebsiella pneumonia •Upon entry alveoli, microbe is causing inflammation reaction −Phagocytosis is fend off by capsule •Abscesses and necrosis of lung tissue lead to very high mortality rate (80%) −Patients with Klebsiella pneumonia tend to die sooner. •COMPLICATIONS: develop if microbe enters blood stream, −Klebsiella pneumoniae may cause wide-spread formation of abscesses in other tissues •Formation of abscess in the lungs and necrosis of lung tissue results in very high mortality rate, which can reach 80% •Patients with Klebsiella pneumonia are also tend to die sooner than patients with other types of pneumonia Mycoplasmal pneumonia •Microbe colonizes ciliary escalator and causes ciliated cells slough off •Inflammation reaction leads to thickening of walls in bronchi and alveoli −This leads to reduced gas exchange in alveoli and difficulty in breathing •COMPLICATIONS: −Mycoplasma pneumoniae infections create opportunities for secondary resp. infections Epidemiology Pneumococcal pneumonia •Classification: ‒Contagious, Notifiable disease •Reservoir: ‒Humans (respiratory s.) •Routes of transmission: ‒Respiratory droplets ‒Direct contacts ‒Indirect contacts ‒Risks rise sharply if §Ciliary escalator destroyed, §Low immune system •Statistics: ‒Accounts to 60% of all bacterial pneumonia cases ‒About 30% humans are asymptomatic carriers Klebsiella pneumonia •Classification: ‒Communicable, Notifiable disease •Reservoir: ‒Humans (guts) •Routes of transmission: ‒Fecal-oral route via human feces ‒Parenteral route ‒Mostly nosocomial disease ‒Risks rise sharply if §Ciliary escalator destroyed, §Diabetes, §Alcoholism - due to low personal hygiene •Statistics: ‒World & US data are NA Transmission of Klebsiella pneumoniae •To get a Klebsiella infection, a person must be exposed to the bacteria. For example, Klebsiella must enter the respiratory (breathing) tract to cause pneumoniae, or the blood to cause a bloodstream infection. •In healthcare settings, Klebsiella bacteria can be spread through person-to-person contact (for example, from patient to patient via the contaminated hands of healthcare personnel, or other persons) or, less commonly, by contaminated environment. The bacteria are not spread through the air. •Patients in healthcare settings also may be exposed to Klebsiella when they are on ventilators (breathing machines), or have intravenous catheters or wounds. Preventing the transmission of Klebsiella pneumoniae •Strict adherence to hand hygiene and wearing gowns and gloves when they enter rooms where patients with Klebsiella-related illnesses are housed. Healthcare facilities also must follow strict cleaning procedures to prevent the spread of Klebsiella. •To prevent the spread of infections, patients also should clean their hands very often, including: Before preparing or eating food; Before touching their eyes, nose, or mouth; Before and after changing wound dressings or bandages; After using the restroom; After blowing their nose, coughing, or sneezing; After touching hospital surfaces such as bed rails, bedside tables, doorknobs, remote controls, or the phone Mycoplasmal pneumonia •Classification: ‒Contagious, Notifiable disease •Reservoir: ‒Humans (respiratory s.) •Routes of transmission: ‒Respiratory droplets ‒Direct contacts (hand shakes) ‒Indirect contacts (fomites) ‒Risks rise sharply if §Ciliary escalator destroyed, §Low immune system •Statistics: ‒World & US data are NA ‒Makes up to 20% of all pneumonia cases Prevention Pneumococcal pneumonia •Quarantine ‒For those who are infected •Antibiotic prophylaxis ‒For those who were in contact with infected •Good hygiene ‒Frequent hand washing ‒Avoiding crowds during outbreaks ‒Keeping hands away from face • •Vaccine ‒PPSV - polysaccharide vaccine ‒PCV 7 (13) (23) - conjugated vaccines Klebsiella pneumonia •Hospitalization ‒For those who are infected •Hospitals ‒Proper sterilization and disinfection of medical equipment •Good hygiene ‒Frequent hand washing ‒Avoiding contacts with human feces • • •Vaccine ‒None Mycoplasmal pneumonia •Quarantine ‒For those who are infected •Antibiotic prophylaxis ‒For those who were in contact with infected •Good hygiene ‒Frequent hand washing ‒Avoiding crowds during outbreaks ‒Keeping hands away from face •Vaccine ‒None Treatment Pneumococcal pneumonia •Antibiotic treatment ‒Penicillin ‒Erythromycin ‒However, stains of Streptococcus pneumoniae increasingly become antibiotic-resistant Klebsiella pneumonia •Antibiotic treatment ‒Cephalosporin ‒Aminoglycosides §Streptomycin §Gentamycin §Tobramycin ‒However, stains of Klebsiella pneumoniae increasingly become multi-drug resistant, §Including last line antibiotics, like Carbapenem Mycoplasmal pneumonia •Antibiotic treatment ‒Tetracycline ‒Erythromycin ‒Mycoplasma pneumoniae is naturally resistant to b-lactams: §Penicillins §Cephalosporins Tetracycline can stain the teeth

Prevention and treatment of hemolytic disease of newborn

•Prevention of the disease can be achieved y blood testing of parents before delivery of the child; If rhesus-negative mother is pregnant with first rhesus-positive child, mother is given rhesus immune globulins at 28th week of pregnancy and within 72 hours of delivery to prevent sensitization of mother to rhesus antigen. •Treatment of the disease can be done only by blood transfusion in newborn.

Mechanism of hemolytic disease of newborn

•Rh-negative humans do not carry Rh (rhesus) factor on their red blood cells (RBC) and have ability to produce antibody against Rh-factor upon exposure to it. •When Rh-negative woman becomes pregnant with Rh-positive child, she become exposed to Rh- factor during childbirth. At this point mother starts production of IgG against Rh-factor. •If she becomes pregnant with second Rh-positive child, maternal IgG against Rh-factor would cross placenta and attack RBC of fetus leading to hemolytic disease of newborn.

•Staphylococcus epidermidis

•S. mutans, S. pneumoniae, S. salivarius, S. viridans they are part of normal flora It is part of normal flora in humans. It does not produce virulent factors and has no ability to invade human host. •However, some strains may form biofilms: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2807625/ •It is the principal staphylococcal species found on skin that plays a vital role in limiting the skin colonization by pathogens •It may represent danger to immuno-compromised patients only

PPD test (Mantoux or Tuberculin test)

•Signs and Symptoms - development of erythema (redness of the skin) with hardened area in the center (induration) within 48-72 hours after intradermal injection of a proteins' dose purified from Mycobacterium tuberculosis. Reaction is read 48-72 hours later by measuring the diameter of hardened area on forearm. A person exposed to M. tuberculosis antigens would develop hardened area 5 mm or more in diameter. •Causes - injection of tuberculin skin test into a person previously exposed to Mycobacterium tuberculosis •Pathogenesis - Reaction develops mainly from T helper-cells that recognize the antigen and release pro-inflammatory cytokines resulting in local inflammation reaction. •The tiny amount of purified protein is injected •Reaction is positive if hardened area (induration) is 5 mm or more pointing that person was exposed to mycobacterium

Secondary immunodeficiency disorders

•They are acquired depletions of certain type of immune cells due to: •Environmental factors - Pollution and/or malnutrition •Advanced age •Use of immunosuppressive drugs •Certain infections and malignancies. Examples: •Syphilis, leprosy, and malaria - affect T-cells and macrophages •Malignancies of lymphoid system - decrease antibody-mediated immunity •AIDS - the most widely-spread disorder - destroys T helper cells, thus inhibiting the initiation of cellular and antibody-mediated immunity

Infectious diseases Anatomy, Physiology, & Ecology

•Skin is a anatomical barrier that protects the body from microbial invasion. •Skin is bathed in secretions and forms distinct ecological habitat for microbes Epidermis - is composed of the outermost layers of cells in the skin. •It is a stratified epithelium, composed of proliferating basal and differentiated keratinocytes. •The outermost cells are dead and are filled with keratin, the protein found in hair and nails •It acts as the body's major barrier separating body content from inhospitable environment, •It prevents the pathogens from entering the body, making the skin a natural barrier to infection. •It also regulates the amount of water lost from the body Dermis - is the layer of skin below epidermis. •The dermis is tightly connected to the epidermis through a basement membrane. •Structural components of the dermis are collagen, elastic fibers, blood and lymphatic vessels, many tiny nerves, glands •Sweat glands - produce sweat that has pH 4-6.8; high salt (NaCl) concentration; lactic and fatty acids •Sebaceous glands - produce sebum, the acidic oily or waxy matter that lubricate and waterproof the skin and hair. It contains •various triglycerides (40%), wax (26%), free fatty acids (30%), including Sapienic acid, the compound unique to humans that has strong antibacterial activity. Subcutaneous tissue •It is underlying the skin. It is rich in fat, providing the thermal insulation of the body

Strategy of antibiotic treatment of mycobacterial infections

•Species from genus Mycobacterium are acid fast bacteria •Their cell wall can not be easily penetrated by antimicrobials and nutrients •As a result, acid-fast bacteria are very slow growing & requiring prolonged treatment •There are relatively few drugs effective in treatment of mycobacterial infections •Successful treatment of such infection necessitates the use of special strategy Step 1. Antibiotics are used to reduce hydrophobicity of cell wall •Ethambutol - It prevents the attachment of mycolic acids to cell wall •Isoniazid - It inhibits the synthesis of mycolic acid •Pyrazinamide - Action is not clear, probably inhibits the fatty acid synthesis Step 2. Bactericidal antibiotics are used to kill a microbe •Streptomycin - irreversibly binds to ribosome & inhibits protein synthesis •Rifampin - irreversibly binds to RNA polymerase & inhibits RNA synthesis •Ciprofloxacin - irreversibly binds to DNA gyrase & inhibits DNA synthesis •Since the course of antibiotics lasts few months, Directly Observed Therapy (DOT) is used during treatment of tuberculosis (see slide notes) Ethambutol •It is bacteriostatic against actively growing Mycobacterium tuberculosis. •It reduces hydrophobicity of cell wall by inhibiting the enzyme arabinosyl transferase involved in synthesis of arabinogalactan and thus preventing the attachment of mycolic acids to the cell wall. •It has various side effects including Optic neuritis; Red-green blindness; Peripheral neuropathy; Damage to liver; Joint pain Isoniazid •It is bactericidal to rapidly growing mycobacteria but bacteriostatic if mycobacteria are slow-growing. •It is prodrug, which is activated in the bacterial cell •It inhibits the mycolic acid synthesis Pyrazinamide •It is bactericidal to rapidly growing mycobacteria but bacteriostatic if mycobacteria are slow-growing. •It is a prodrug, which is activated in the bacterial cell •Mechanism of action is not clear but may be involve inhibition of fatty acid synthase and thus interfering with synthesis of long chain (C16) fatty acids. DOT •It means that a trained health care worker or other designated individual (excluding a family member) provides the prescribed TB drugs and watches the patient swallows every dose. • Strategy •Mycobacteria are acid-fast bacteria with highly hydrophobic cell wall. So, mycobacterial infections must be treated by cocktail of antibiotics for a few months and up to 1-2 years. •The cocktail must include antibiotics that reduce hydrophobicity of cell wall and bactericidal antibiotics that can kill bacterial cells even at low concentration. •Effective concentration of bacteriostatic antibiotics is impossible to achieve in acid-fast bacteria. •At the beginning of treatment, antibiotics must be taken in the presence of healthcare worker (directly observed therapy or DOT).

Obtaining specific antibodies

•Specific antibody can recognize epitope of a particular antigen and has no cross-reaction −Specific antibodies can be used in diagnostics and even in treatment of the disease

Virulence factors covering bacterial cell with human proteins

•Staphylococcus aureus - Protein A; Clumping factor A; FnBPA; Coagulase; •Streptococcus pyogenes - Protein G; M protein; Protein F

Vaccine against strep throat

•Strep throat is pharyngitis caused by Streptococcus pyogenes •Development of effective vaccine against strep throat is very difficult as there are over 80 known serotypes of Streptococcus pyogenes •Any confirmed strep throat case must be promptly treated with antibiotics •If strep throat is left untreated, there is a great chance of serious complications.

Effects of combination of antimicrobial medications

•Synergism and antagonism of the drugs - for details see slide notes to slide 17 •EXAMPLES: •Compound A has highest antimicrobial effect as judged from the size of clear zone •Compound B has lesser antimicrobial effect as judged from the size of clear zone •Compound C has no antimicrobial effect as there is no clear zone formed •Appearance of additional symmetric clear zone between disks A and B indicates that there is mutual synergistic effect of A and B compounds. •Appearance of additional asymmetric clear zone between disks B and C indicates that compound C has synergistic effect on compound B. However, compound B has no effect no compound C

Effect of combination of antimicrobial medications

•Synergism occurs when the effect of two drugs together is greater than the effect of either alone. •EXAMPLE: Ethambutol + Isoniazid + Streptomycin in TB treatment. The first two reduce hydrophobicity of cell wall of M. tuberculosis by inhibiting the synthesis of mycolic acid, while the third drug irreversibly binds to ribosome and inhibits the protein synthesis in the cell. •EXAMPLE: Sulfa drug and trimethoprim are inhibiting two enzymes of folic acid biosynthesis metabolic pathway. Bacteria is unlikely to develop resistance against both antibiotics at the same time •Antagonism occurs when the effect of two drugs combined is less than an effect of either drug used alone. •EXAMPLE: Penicillin and chloramphenicol combined have bacteriostatic effect, while penicillin alone kills bacteria

Indirect labeling of antibody

•The tag is attached to another (secondary) antibody directed against of Fc of (primary) antibody directed against a microbe •It is more advantageous labeling as the same tagged secondary antibody can be used to label any antibody produced in the same biological species •For example, fluorescein-tagged anti-human IgG antibody from donkey can be used to label and detect any human antibodies.

Direct labeling of antibody

•The tag is attached to antibody directed against microbe •The antibody can be labeled by the tags of various nature: •Radioactive, •Fluorescent dye, •Enzyme •Others (like toxins or drugs)

Treatment varicella, rubeola or rubella

•There are no treatment for varicella, rubeola or rubella ‒Antibiotics can be used only to treat secondary infections caused by bacteria

Actinobacteria

•They are Gram-positive bacteria have high GC-content, 50-75% •Some of actinobacteria are acid fast bacteria. •Natural reservoirs are soil, fresh water, human skin

Mechanism of transfusion reaction

•Transfusion of wrong type of blood triggers production of antibodies directed against type A and/or type B sugar present on red blood cells (RBC) in transfused blood. Binding of these antibodies to RBC of transfused blood activates the compliment system via classical pathway leading to formation of membrane attack complex. It also recruits natural killers. In both cases the targeted RBC is lysed. •If wrong type of blood is transfused, the new transfusion of correct type of blood is required.

Vaccine against herpes

•Vaccine can prevent new infections •However, if infection is established it can not be cured.

Hypersensitivity I

•What is type I hypersensitivity? Type I hypersensitivity, or sometimes IgE-mediated hypersensitivity or immediate hypersensitivity, is a type of immune reaction in which tissue is damaged due to IgE antibody. Most allergies are caused by type I hypersensitivity reactions. This video covers the pathophysiology, complications, signs and symptoms, and treatment for type I hypersensitivity reactions.