Final Lecture Exam: micro Dr. Dan

Staphylococcus Species

-There are currently 31 species--- 12 of which colonize humans • The three species of major medical importance are: - S. aureus: primary pathogen - S. epidermidis: common skin microflora but can lead to nosocomial and opportunistic infections. - S. saprophyticus: another opportunist very similar to S. epidermidis and occasionally causes primary UTI (urinary tract infection) in women.

Classification method for Streptococci

-first classified using the Lancefield Classification system based on cell wall carbohydrates displaced on each species - 17 different alphabetical groups The four groups of clinical importance include: • Group A: Strep. pyogenes - the primary human pathogen - Causes 95% of all streptococcal diseases • Group B: Strep. agalactiae - responsible for neonatal infections • Group C: primarily an animal pathogen but can cause skin and soft tissue infections in humans • Group D: Enterococcus - causes several human infections, especially nosocomial infections and UTIs Hemolytic patterns on sheep blood agar are • Beta hemolysis: complete hemolysis with a clear zone around the colonies. GAS, GBS, GCS • Alpha hemolysis: incomplete hemolysis with a greenish zone around the colonies. (Strep. pneumoniae & viridans strep.) • Gamma hemolysis: NO hemolysis (Some GDS)

Bacillus anthracis Bioterrorism

-in 2001, Bacillus anthracis spores were intentionally distributed through the postal system causing 22 cases of anthrax and 5 deaths -A brown powder placed in letters mostly caused cutaneous anthrax, whereas a finer powder in other letters mostly caused inhalation anthrax

diseases caused by Group A Streptococcus pyogenes (GAS)

-meningitis -sinusitis -otitis -pharyngitis, tonsilitis, adenitis -pneumonia -impetigo, erysipelas, cellulitis, strep throat -necrotizing fasciitis -myositis -carditis -chorea -polyarthritis -subcutaneous nodules -erythema marginatum -scarlet fever -acute post-streptococcal glomerulonephritis -toxic shock syndrome -puerperal fever -septic arthritis -osteomyelitis

True Enteric Pathogens: Salmonella and Shigella

-non-coliform of the Enterobacteriaceae Family -non-lactose fermenters -selective/differential agar used: MacConkey Agar (distinguishes between lactose fermenting and non-lactose fermenting Enterobacteriaceae) lac += pink colonies. lac -+= clear colonies on yellow backgrd

Giselle's 4-week-old newborn develops meningitis. Short, gram-positive bacilli are isolated from a spinal tap. Giselle reveals that she had eaten unpasteurized cheese from Mexico during the pregnancy, and she recalled having mild gastroenteritis. Which of the following is the Most Likely etiological agent? a. Bacillus cereus b. Listeria monocytogenes c. Bacillus anthracis d. Clostridium botulinum e. Corynebacterium diphtheriae

b. Listeria monocytogenes

During her summer job at Petsmart, Nathalie got yelled at by her boss about the danger of leaving dog urine on the floor for too long. He claimed it could potentially get customers sick. What possible pathogen is Most Likely to be found in the urine of dogs? a. Yersinia pestis b. Borrelia burgdorferi c. Leptospira interrogans d. Bartonella henselae e. Vibrio parahaemolyticus

c. Leptospira interrogans

ectopic pregnancies

fertilized ovum implants on tissue other than endometrial lining of uterus

Staph. epidermidis is what type of hemolysis

gamma - hemolysis

HSV 1 & 2

herpes labialis=cold sores

S. aureus Systemic Diseases

most systemic staphylococcal infections have a focal pattern spreading from a local cutaneous infection to other sites via the bloodstream. Bacteremia: the presence of viable bacteria in the blood Osteomyelitis: infection of the bone Endocarditis: infection of the inner heart lining and heart valves

The Genus Clostridium virulence factors

produces the most potent exotoxins that are among the most poisonous substance on earth Clostridium species can cause wound & tissue infections, and food intoxication.

Streptococcus pneumoniae and Ottis Media

strep. pneumoniae is the leading cause for Otitis Media (middle ear infection) is a very common infection in children in the U.S. • Pneumococcus can gain access to the chamber of the middle ear by way of the eustachian tube. • Children under 2 years are most susceptible because of their shorter eustachian tubes but usually outgrow recurrent infections.

Rebecca Craighill Lancefield

the person that identified ALL strains of streptococci

why do pathogens cause blood clots

to prevent neutrophils from arriving to area

Clostridium botulinum and Botulism prevention

use proper canning food techniques - adequate pressure cooking can achieve sterilization bulging cans or bottles that look or smell spoiled should be discarded botulinum toxin is rapidly inactivated at 100 degrees C (10 minutes)

3 antibiotics in Thayer Martin agar

vancomycin (gram positive inhibitor) polymixin (gram-negative rods inhibitor) Nystatin (fungal inhibitor)

Chlamydia trachomatis Serotype D-K

• 2nd most common STD in the U.S. but #1 most reported STD. • 10% of people carry C. trachomatis in their genital tract. • Around 50% of infected men and 75% of infected women are asymptomatic. • In males, causes non-gonococcal urethritis (NGU), can produce a clear to yellow discharge, and may also lead to scarring and infertility. • In females, causes urethritis and is the #1 cause of Pelvic Inflammatory Disease (PID). Can also lead to infertility and ectopic pregnancy. • In newborns, can cause Inclusive Conjunctivitis, which is acquired through contact with secretions of an infected genitourinary tract. • Within 5-6 days, an abundant, watery, exudate collects around the conjunctival sac. • Prevented with eye prophylaxis of all newborns (as for gonococcal infection) with antibiotics.

Human Immunodeficiency Virus (HIV)

• A Retrovirus - Enveloped, RNA virus • Called Retroviruses because they reverse the usual order of transcription. • HIV is the cause of Acquired Immuno-deficiency Syndrome (AIDS) • Capsid contains 3 important enzymes - Reverse Transcriptase: makes DNA copy from viral RNA - Integrase: integrates viral DNA into host chromosome - Protease: required for viral release and maturation • GP120 viral spikes attach to CD4 molecules and other receptors on immune cells. • GP41 allows for fusion into host cell

Staphylococcus aureus

• A facultative anaerobe and is catalase positive (releases oxygen bubbles from H2O2 ) • The optimum temperature is 37degreesC though it can grow between 10degreesC and 46degreesC. • Produces many virulence factors • It is the most resistant of the non-endospore forming pathogens. They can withstand: - High salt concentrations (7.5-10%) - Extremes in pH (pH 4-10) - Drying (persist on skin and fomites in a clinical setting) - Heat (temperatures up to 60o C for an hour) - Antibiotics that they have developed resistance to (e.g., MRSA, VRSA)

Clostridium perfringens

• A large, rectangular, spore former found in soil, dust and the feces of humans and animals. • Endospores are not usually seen in clinical specimens. • Causes food intoxication, mostly from heavily contaminated meats (especially stews and gravies) that are reheated or kept warm for long periods of time. Presents as watery diarrhea with severe abdominal cramping. No vomiting.

Tuberculoid Leprosy

• A superficial infection characterized by shallow skin lesions containing few bacilli. • No skin disfigurement is caused but damage to nerves usually results and causes loss of pain perception. • Easily treated than other form of leprosy.

Clostridium tetani and Tetanus

• C. tetani releases Tetanospasmin into local tissue which is absorbed by peripheral nerves and carried to target neurons in spinal column. • The neurotoxin inhibits muscle relaxation, causing muscles to contract uncontrollably called spastic paralysis • Spastic paralysis begins in the jaw area - trismus (jaw muscle spasms causing lockjaw) and risus sardonicus (facial muscle spasms producing a wry, masklike grin), and descends, if untreated, causing paralysis of large muscle groups (rigid back spasm), and death from paralysis of throat and respiratory muscles.

Neisseria meningitidis

• Called the Meningococcus and causes epidemic cerebrospinal meningitis • Highest incidence of disease in children less than 5 years of age • 2nd most common cause in adults, after Streptococcus pneumoniae. • Humans are the reservoir of infection and harbor the pathogen in the nasopharynx. • The disease spreads within families and communities, with sporadic or epidemic incidences in late winter or early spring. -12 different strains with serotypes B, C, and Y responsible for most cases of infection in U.S.

Neisseria meningitidis virulence factors

• Capsule - confers virulence and antiphagocytic • Fimbriae • IgA Protease • Endotoxin (LOS) Transmission by aerosolized respiratory droplets (esp. in families or crowded situations such as military barracks or dormitories).

Molluscum Contagiosum

• Caused by the Molluscum Contagiosum Virus (MCV) which forms clusters of benign, pink, waxy, tumor-like growths on skin • Transmitted by direct contact and fomites • In the U.S., it is most common in children 1-10 years of age and is considered an STD in adults -self resolves overtime

Haemophilus ducreyi

• Causes Chancroid, an STD characterized by painful genital ulcers. • Common in the tropical areas of the world (Africa, Asia, Latin America). • Transmitted by direct contact with infected lesions in the genitals or perianal area. • Afflicts mostly males and is more common in the MSM community.

Rickettsia typhi

• Causes Endemic Typhus (or Murine Typhus) • Reservoir is infected mice and rats and it is transferred to humans via fleas. • In the U.S., most reported cases arise sporadically among workers in rat-infested industrial sites • Causes a milder disease than epidemic typhus (R. prowazekii) with symptoms also including fever, rash, headache, muscle aches, and malaise.

Chlamydia trachomatis Serotype L1-L3

• Causes Lymphogranuloma venereum (LGV) - a sexually transmitted disease endemic in Africa, Asia, and South America. • About 500 cases per year in the U.S. • Bacteria invades the lymphatic tissue in the genital areas and form large tropical buboes. • Swollen lymph nodes can rupture and cause deforming edema of the genital and anus (bloody proctocolitis).

Chlamydia trachomatis Serotypes A-C

• Causes Ocular Trachoma - infection of the epithelial cells of the eye. • Leading cause of microbial blindness worldwide. • Several million cases occur endemically in Africa and Asia and transmission favored by contaminated fingers, fomites, and flies. • Symptoms include conjunctivitis followed by build up of pebbled appearance in the eyelids. Inflammation results in corneal damage and blindness.

Haemophilus aegyptius

• Causes acute communicable bacterial conjunctivitis (pink eye) • Presents with subconjunctival hemorrhage and purulent discharge (pus) • Highly contagious! • Transmitted via fomites and contaminated fingers • Treated with antibiotic eyedrops

Epstein-Barr Virus (EBV) 4

• Causes the disease known as Infectious Mononucleosis ("the kissing disease") • Transmission: direct oral contact and contamination with saliva • Infects lymphoid tissue and salivary glands • Very ubiquitous in people. By mid-life, 90-95% of all people have been infected. • In some people, the entire course of infection and latency is asymptomatic • In children and young adults mononucleosis causes sore throat, high fever, and cervical lymphadenopathy

Vibrio cholerae

• Comma-shaped Gram (-) Bacilli with a unipolar flagellum • Found in humid environments but mostly infected people are the reservoirs. • Etiological agent of Cholera, a devastating disease for centuries • Transmission is through fecal contamination of food and water • Ranks among the top causes of morbidity and mortality worldwide, affecting several millions of people in endemic regions of Asia and Africa. • Uncommon in the U.S. but brought by asymptomatic carriers or occasional shellfish ingestion in the Gulf States.

Bacillus cereus

• Common soil microbe that can be an airborne and dust-borne contaminant • Multiplies very readily in cooked foods such as rice, potato, and meat dishes. • Spores and toxins survive short periods of cooking and reheating; when the food is stored at room temperature, the spores germinate and release enterotoxins. • Enterotoxins result in food intoxication - acute vomiting, nausea, abdominal cramps, and diarrhea. • Symptoms disappear within 24 hours.

Clostridium tetani

• Common spore-forming resident of soil and the gastrointestinal tract of animals. • Bacterial cells resemble a tennis racket or drumstick because of its round, terminal endospores. • Spores enter through a wound, especially deep implantation, and germinate in anaerobic tissue. • Vegetative cells release the tetanus toxin (Tetanospasmin) which blocks muscle relaxation.

Medically important gram- bacilli

• Comprise a large group of Non-endospore Forming Bacteria: -Enterobacteriaceae Family (enterics) -Zoonotic Pathogens -Other Pathogens

Campylobacter jejuni

• Curved or spiral Gram (-) bacilli, often appearing in S-shaped or gull-winged pairs. • Has emerged as one of the most important causes of bacterial gastroenteritis worldwide • Acquired from ingestion of raw or undercooked poultry, other contaminated beverages and food (water, milk, meat) or direct contact with infected animals. • Adheres to the intestine, burrows through the mucus and multiplies. • Secretes an enterotoxin which causes headache, fever, abdominal pain, bloody or watery diarrhea. • Normally resolves on its own.

Other Chlamydial pathogens

Chlamydia pneumoniae: • Causes a mild atypical pneumonia (walking pneum.) • Transmission via aerosolized respiratory droplets • Implicated in ~20% of community acquired pneumonia • Can cause severe reaction in asthmatic patients. Chlamydia psittaci: • Causes Ornithosis (Parrot Fever) • A zoonosis transmitted via inhalation of dried bird feces • Highly infectious disease of birds, especially turkeys in the U.S. • Also causes an atypical pneumonia or flu-like infection with fever, headache and muscle aches. -also called Bird Fancier's Disease

Enterobacteriaceae antigens and virulence factors

Classified by 2 Surface Antigens: 1. O - LPS Antigen 2. H - Flagellar Antigen 3. K - Capsule/Fimbrial Antigen Virulence Factors: • Fimbriae - for adherence • Endotoxin - LPS • Exotoxins - mostly enterotoxins causing gastroenteritis Examples: E. coli O157:H7 E. coli O104: H4 E. coli K strains

Treponema pallidum diagnosis

Dark field Microscopy Fluorescence Antibody Test

Neisseria meningitidis diagnosis

Diagnosis: • The most useful specimens are blood and cerebrospinal fluid (CSF) which are cultured and/or Gram stained. Meningococcal Vaccine: • A subunit vaccine using capsular polysaccharides. Recommended by CDC for all ages, especially during outbreaks, military, and college freshmen living in dormitories. -Antibiotic prophylaxis given to people with significant exposure to those sick with the disease

Helicobacter pylori

• Curved, spiral lophotrichous bacilli • Humans are the only reservoir • Fecal-oral transmission • The primary habitat is the harsh human stomach! • Bores into the stomach epithelium and secretes urease which hydrolyzes stomach urea to produce an alkaline ammonia cloud. Neutralizes stomach acid. • Implicated in 90% of stomach and duodenal ulcers and a major factor in the development of stomach cancer. • Immune response causes inflammation (gastritis), ulcers and cancer.

Mycobacterium tuberculosis

• Does not produce exotoxins or enzymes that contribute to infectiousness. • Contains waxes and a cord factor that prevent its destruction by phagocyte lysosomes. • In infected tissues, cord factor contributes to serpentine cord formation • Transmission: fine airborne respiratory droplets Per the CDC: • 1/4th of the world's population is infected with TB • 1-2 million deaths per year • Leading killer of people infected with HIV

Extrapulmonary Tuberculosis

• During the course of reactivation, the bacilli disseminate rapidly to extrapulmonary sites such as: - kidneys - bones - brain - genital tract • Very high mortality rate • Treatment of all Tuberculosis stages involves multidrug therapy lasting from 6-24 months. • BCG Vaccine available outside of U.S.

Epstein-Barr Virus and Cancer

• EBV has been implicated in Burkitt's lymphoma, a B-cell cancer that usually develops in the jaw and grossly swells the cheek. • The prevalence in Africa may be associated with chronic coinfections with other diseases, such as malaria. • EBV also has oncogenic implications in nasopharyngeal carcinoma in older Chinese and African men.

Hepatitis B Virus (HBV)

• Enveloped, icosahedral, double stranded DNA • Tropism for Liver • A minute amount of blood can transmit infection and also spread through sex, semen, saliva, IV drug use, childbirth and breast-feeding • Can become a chronic infection • Increases risk of cirrhosis and hepatocellular carcinoma -can cause fever, body rash, enlarged liver, arthritis

Botulinum food posoining

• Improper canning of food, especially home-made canned vegetables, smoked meats and cheese spreads, does not kill spores and they can germinate in the cans producing botulinum toxin. • Incubation is 1-2 days. Botulism characteristically affects the muscles supplied by the cranial nerves first, causing eyelid drooping, double vision, loss of facial expression, dry mouth, difficulty chewing and swallowing, followed by flaccid paralysis.

Gonorrhea in Males

• Infection primarily restricted to the urethra causing urethritis, with painful urination and prolific pus production. • Untreated cases may resolve spontaneously within several weeks but it can occasionally spread to the prostate gland and epididymis, leading to scar tissue and infertility.

Influenza Genetic Changes

• Influenza A constantly changes because of its high mutation rate - Antigenic Drift: constant genetic change of the glycoproteins through mutation. - Antigenic Shift: genetic reassortment between genes from different viral subtypes. Example: H1N1 + H2N2 strains infecting same cells can give rise to H1N2 or H2N1 • Constantly have new Flu strains occurring because of Antigenic Drift and Shift. (why we need constant vaccine updates) • Immunity to 1 strain does not protect against other strains

Influenza Transmission & Control

• Influenza virus binds primarily to ciliated cells of the respiratory mucosa causing varying degrees of respiratory illness: fever, headache, sore throat, coughing, shortness of breath, and can lead to pneumonia • Spread via respiratory droplets Major Pandemics • 1918 (Spanish Flu) H1N1 • 1968 (Hong Kong Flu) H3N2 • 2005 (Bird Flu) H5N1 • 2009 (Swine Flu) H1N1 • Antivirals (Tamiflu) are available along with supportive care to treat infection • A yearly flu vaccine is highly recommended -The 1918 Spanish Flu killed up to 50 million people world-wide making it the most devastating plague in human history

Influenza Life Cycle

• Influenza's segmented genome complicates the packaging of new viruses. • If more than 1 Influenza virus infects the same cell, the genome segments of each different subtype could get mixed up during packaging. • This leads to Antigenic Shift - Major changes in the Influenza A virus due to recombination of viral strains from two different host species. (major cause is pig cells)

Botulism

• Ingested or secreted botulinum toxin travels to the neuromuscular junctions of skeletal muscles. • In the normal state, neurons release acetylcholine which cross the synapse and stimulate muscle contraction. • In botulism, the toxin blocks the release of acetylcholine and keeps the muscle from contracting. • This results in flaccid paralysis

Progression of HIV Infection

• Initial Infection: Vague, Mononucleosis-like symptoms that soon disappear - Marked by high levels of free virus in the blood • Asymptomatic Phase: 2-15 years - Rapid drop in free virus and antibodies level rise - Over time, levels of T helper cells begin to decline • AIDS: T helper cell # falls below 200/μL initiating fever, swollen lymph nodes, diarrhea, weight loss, neurological symptoms, opportunistic infections & cancers

Fancisella tularensis

• Intracellular pathogen transmitted by contact with infected animals or ticks. • Causes Tularemia, a zoonotic disease of mammals endemic to the northern hemisphere. • Human infection starts with transfer of infected animal blood, most commonly by trauma while skinning a rabbit, or when a tick from the rabbit bites a human. • Ulceroglandular tularemia (from cuts or vector bite) - begins with fever, chills, malaise, and an ulcerating lesion at the inoculation site.

Brucella

• Intracellular zoonotic pathogen transmitted to humans from infected animals. • 3 species: B. abortus (cattle), B. melitensis (goats), B. suis (pigs) • Spread from infected animals by direct mucosal contact, traumatic skin implantation, or ingestion. • Causes Brucellosis or Undulant Fever, a flu-like disease with a fluctuating pattern of fever lasting weeks to a year. • Occupational hazard of veterinarians, slaughterhouse workers, farmers, and anyone who ingests unpasteurized dairy products (milk and soft cheese).

Haemophilus influenzae

• It was erroneously believed to be the causative agent of the flu, until the influenza virus was discovered. • Responsible for many cases of acute bacterial meningitis, primarily by the b serotype. • Transmission via direct contact • The Hib Vaccine has significantly decreased the reported cases of bacterial meningitis in children. • Other types of H. influenzae are still a main common cause of otitis media in children and cherry-red epiglottitis .

Borrelia burgdorferi and lyme disease

• Ixodes tick requires 32-48 h of feeding to transmit disease • Lyme disease is nonfatal but often evolves into a slow progressive syndrome that mimics neuromuscular and rheumatoid conditions. • Early symptom is Bull's Eye Rash (70% of cases) • 4-6 weeks after tick bite, develop fever, headache, mild stiff neck, joint arthritis, and dizziness. • Can progress to cardiac and neurological symptoms. • High Risk groups include anyone involved in outdoor activities: -Hikers -Campers -Boy scouts -Hunters •Infections most common in summer and early fall • Prevention: protective clothing, boots, leggings, insect repellants • Dogs can also acquire the disease - vaccine available for them

Streptococcus Morphology

Morphology: - The streptococci are characterized by being Gram positive, spherical/ovoid cells typically arranged in long beadlike chains. - Non-spore forming and non-motile - Common inhabitants of the throat, nasopharynx, and occasionally the skin in humans. • Most are facultative anaerobes that ferment a variety of sugars. • Lack catalase which allows differentiation of streptococci from the staphylococci. • Most pathogenic forms are fastidious and require enriched media to grow (like blood agar). • Their colonies are usually small, round, translucent, and grayish (smaller than staphylococcal colonies). -beta hemolysis

Differentiating between staphylococcus and streptococcus and between staphylococcus species

Staph is catalase postive Strept is catalase negative Coagulase Test: -s. aureus is positive -Streptococci, S. epidemidis, and S. saprophyticus is negative Coagulase Test is the most important test to distinguish Staph. aureus from the other staphylococci.

Staphylococcus Morphology

Staphylococci are -gram positive -spherical shaped cocci that are arranged in clusters -Lack spores and flagella (non-motile) -Common inhabitants of the skin & mucous membranes

4 Genera of Cocci that are a significant cause of infections in humans

Staphyococcus Streptococcus Entercoccus Neisseria Because these bacteria stimulate the formation of PUS they are collectively referred to as the pyogenic cocci (pus forming cocci)

Strep. pyogenes and Necrotizing Fasciitis

The Flesh Eating Bacteria • This streptococcal infection has received notoriety as being a devastating disease. • It has always been around and is the result of virulent Group A streptococcal toxins and enzymes which destroy tissues. •Strep. pyogenes enters the tissue through a break in the skin. • A cellulitis develops • after which bullae (large blisters) form • followed by gangrene(death of tissue associated with loss of blood supply • Massive tissue necrosis • With systemic symptoms including multi-organ failure.

Herpesviruses

• Large, enveloped, icosahedral dsDNA virus • Named for the tendency of some herpes infections to produce a rash that spreads (creeps). • All members show latency and cause recurrent infections. • Infections become more severe with age, cancer chemotherapy, immunosuppression, etc. • Comprises a large family with 8 known to infect humans: - HHV 1 & 2: Herpes Simplex Virus 1 & 2 (HSV 1 & 2) - HHV-3: Varicella-Zoster Virus (VZV) - HHV-4: Epstein-Barr Virus (EBV) - HHV-5: Cytomegalovirus (CMV) - HHV-6 & HHV-7 - HHV-8: Kaposi's Sarcoma-associated Herpes Virus (KSHV)

Poxviruses

• Largest and most complex animal virus family • Enveloped with a large, brick-shaped appearance • Possess dsDNA and have the largest genome of all viruses • They multiply in the cytoplasm in well-defined sites called factory areas (carry own polymerases) • Produce eruptive skin pustules called pocks or pox, which leave small, depressed scars (pockmarks) upon healing. • Important members of the Poxvirus family include: • Variola virus - causes Smallpox • Vaccinia virus - used to make Variola vaccine • Cowpox virus - used in Jenner's work • Monkeypox virus - can infect humans

Neisseria meningitidis and meningitis

• Meningococcus enters the respiratory tract, crosses the mucosal barrier and enters the bloodstream. • Bacteremia allows it to travel to the brain and cross the blood-brain barrier to establish infection in and around the meninges. • Meningitis symptoms include headache, fever, nausea, vomiting and stiff neck. • Endotoxin release also can cause hemorrhage and shock. • Mortality approaches 100% if untreated and drops to 10% with treatment.

Primary Tuberculosis

• Minimum infectious dose is 10 cells • Bacilli are phagocytosed by alveolar macrophages & multiply intracellularly • Weeks later, the immune system mounts a cell-mediated assault, forming tubercles

HPV and Genital Warts

• Most common STD in the U.S. • In excess of 30 million carriers of 35 types of HPV associated with genital warts (most common types are 6, 11, 16, and 18) • HPV 16 and 18 cause an estimated 70% of cervical cancer and most HPV-caused anal, vulval, vaginal and penile cancer. Treatment of Warts: - Most common warts regress over time - Physical removal via topical medication, cauterization, freezing, or laser surgery Two effective subunit HPV vaccines are available - Cervarix (16, 18) and Gardasil 9

Rickettsia rickettsii

• Most common rickettsial infection in the U.S • Tick-borne disease with small mammals serving as the reservoir (squirrels, chipmunks, raccoons). • Etiological agent of Rocky Mountain Spotted Fever (RMSF)

Gonorrhea in newborns

• Newborns may be infected from gonococcus carriers as they pass through the birth canal. • Can cause eye inflammation, purulent conjunctivitis and edema, which can lead to blindness. • Prevented by prophylaxis after birth using silver nitrate or other antibiotic drops. • Preventable neonatal disease so pregnant woman should be screened.

Adenoviruses

• Non-enveloped (naked) virus • icosahedral capsid, dsDNA • 30 types are associated with human disease • Infect lymphoid tissue, respiratory & intestinal epithelia and conjunctiva of the eye • 2 major serotype groups: Serotypes 1-7 (Respiratory) - Spread by respiratory droplets and ocular secretions - Cause colds, pharyngitis, viral conjunctivitis Serotypes 40-42 (Gastroenteritis) - Spread through fecal-oral route - Causes acute watery diarrhea

Papillomaviruses

• Non-enveloped, icosahedral capsid, dsDNA • Cause Papillomas (Warts) - benign squamous epithelial growth • Over 100 different strains of the Human Papillomavirus (HPV) • Transmissible through direct contact, contaminated fomites, or autoinoculation • Incubation: 2 weeks to more than a year EX: Common warts, Periungual warts, plantar warts

Clostridium perfringens and Gas Gangrene

• Spores introduced through anaerobic wounds will germinate and release gas and alpha toxin. Alpha toxin: causes RBC rupture, edema, and tissue destruction. • The gas formed in tissue is due to fermentation of muscle carbohydrates that are released during myonecrosis (muscle death). • Symptoms include: swelling, bullae (large blisters), crepitus, tissue necrosis, fever and shock. The infection is rapidly fatal if untreated. • Treatment includes debridement (surgical removal of dead or damaged tissue), amputation, large doses of antibiotics, and hyperbaric oxygen therapy.

Rickettsia prowazekii

• Spread via the Human Louse with humans serving as the only host and reservoir. Louse defecates on bite wound or feces scratched in. • Etiological agent of Epidemic Typhus (or Louse-Borne Typhus) • Transfer of lice is increased by overcrowding, infrequently changing clothes, sharing clothes, and poor hygiene. • Low incidence in the U.S. but still present in regions of Africa, Central America, and South America.

Localized S. aureus Infections

• Staphylococcus aureus usually invades the skin through wounds, follicles or skin glands. Abscess (Boils): an inflamed lesion with a core of pus - Furuncle: abscess resulting from an infected hair follicle. - Carbuncle: deeper abscess formed by an aggregation of furuncles. Impetigo: an infection of the epidermis characterized by honey-crusted skin lesions. Common in newborns and young children. IF Impetigo is left infected the infection can start going into blood stream and cause serious complications

Streptococcus pyogenes Group A

• Strict parasite • Inhabits throat, nasopharynx, occasionally skin • Surface Antigens: -C-carbohydrates are unique techoic acid used for basis of Lancefield group. Protects against lysozyme. - M protein is fimbriae • Exoenzymes: -Streptokinase digests blood clots - Hyaluronidase is a spreading factor • Exotoxins: - Hemolysins lyse erythrocytes - Erythrogenic toxin is an exotoxin responsible for fever and rash in strep throat infections.

Bacillus anthracis and Anthrax

• The anthrax bacillus undergoes its cycle of vegetative growth and sporulation in the soil. • Animals and humans become infected when they come into contact with the spores and they germinate inside a host to form vegetative cells which release the anthrax exotoxin. • There are 3 types of Anthrax, each dependent upon the portal of entry. - Cutaneous Anthrax - Gastrointestinal Anthrax - Inhalation Anthrax

Escherichia coli

• The best-known fecal coliform and the most abundant intestinal facultative anaerobe. • Most species are nonpathogenic and motile. • Can cause an opportunistic infection when it enters the urethra and is the most common cause of urinary tract infections (UTIs). • Some strains are pathogenic with differing virulence factors and effects.

Inhalation Anthrax

• The deadliest form of anthrax, with a 99% mortality rate if left untreated. • Anthrax spores are inhaled into the lungs. • They are engulfed by macrophages and transported to the lymph nodes where they germinate and secrete exotoxin. • The anthrax toxin kills macrophages, and leads to pulmonary edema, internal hemorrhaging, shock, and rapid death. Anthrax is treatable with antibiotics and a subunit vaccine is available for high-risk groups (military, veterinarians) and for livestock.

Bartonella henselae

• The most common agent of Cat-Scratch Disease • Carried by 40% of cats, especially kittens, and transmitted via cat scratches or bites. • Local papules appear at site of inoculation and the lymph nodes can become infected. • Prevention by thorough degerming of a cat scratch or bite.

Cutaneuos anthrax

• The most common and least dangerous of all forms. • Spores enter through the skin from small cuts and abrasions. • Skin inoculation site forms a papule (raised lesion) that erupts to form a painless, black necrotic lesion called an eschar.

Human Herpes Virus 6 & 7

• The most common herpesvirus, with up to 95% prevalence in tested human populations. • Transmitted by close contact with saliva and other secretions and targets T cells. • Etiological agent of Roseola, an acute febrile disease in babies between 2 and 12 months of age. - Illness begins with fever followed by a faint rose pink rash over the neck, trunk, and buttocks. The disease is self-limiting, and children recover in 2-4 days. • Adults may get mono-like symptoms, lymphadenopathy and hepatitis

Gonorrhea in females

• The primary site of infection is the cervix, but gonococcus can be isolated from the urethra, vagina, and rectum. • Symptoms include vaginal discharge, painful urination, vaginitis, urethritis, and salpingitis (inflammation of fallopian tubes) • Can cause PID (pelvic inflammatory disease) • Women can become infertile or develop ectopic pregnancies later in life because of prior asymptomatic gonorrheal infection due to scarring of the fallopian tubes.

The Viridans Streptococci

• These streptococci are characterized by alpha hemolysis (hence viridans = "green") • They are the most numerous and widespread residents of the oral cavity, nasopharynx, genital tract, skin • They are not very invasive but dental or surgical procedures facilitate entrance. - At least 24 species have been identified and have been divided into 5 groups. - Common examples are: - Strep. mitis - Strep. sanguinis - Strep. mutans - Strep. salivarius

Haemophilus

• Tiny, pleomorphic Gram (-) rods • Very fastidious and grown in Chocolate Agar • Normal colonists in nasopharynx of some healthy individuals 3 Species of Medical Importance: • Haemophilus influenzae • Haemophilus aegyptius • Haemophilus ducreyi

Secondary Tuberculosis

• Tubercles filled with masses of bacilli expand and drain into the bronchial tubes and upper respiratory tract. • Gradually the patient experiences more severe symptoms: - violent coughing - greenish or bloody sputum - low fever and night sweats - weight loss and fatigue - chest pain • Untreated reactivated tuberculosis has nearly a 60% mortality rate

Tertiary Syphilis

• Up to decades after the secondary rash clears, tertiary syphilis can occur. • Can affect the heart, nerves, skin, joints and eyes. • No longer contagious. • Formation of Gummas - painless swollen masses that invade skin and bones. • Can develop Neurosyphilis - mental deterioration and psychological problems

Intracellular Bacterial Parasites

• Very Small, Pleiomorphic Gram (-) Rods • Facultative or Obligate Intracellular Parasites (OIP) 5 Medically Important Species: • Rickettsia rickettsii • Rickettsia prowazekii • Rickettsia typhi • Bartonella henselae • Chlamydia trachomatis

Parvoviruses

• Very small, non-enveloped, icosahedral virus • The only single stranded DNA virus • Cause distemper in cats, enteric disease in dogs, fatal cardiac infection in puppies • Parvovirus B19 causes infection in human - Disease is called erythema infectiosum or Fifth Disease - Common childhood infection spread by respiratory droplets - Infection may go unnoticed, though the child may have a low-grade fever, a characteristic "Slapped Cheek Rash", along with body rash. - Severe fatal anemia can result if pregnant woman transmits virus to fetus (hydrops fetalis) - only get it once, life immunity

Primary Syphilis

• Weeks after infection, a painless chancre forms at the infection site. • 40-60% of males and 90% of females do not recall their primary lesions because they are painless and inconspicuous. • Highly Infectious! • The chancre heals spontaneously as T. pallidum enters the bloodstream. • Chancre can also appear in other areas in the body that come in contact with an infected lesion

S. aureus notable enzymes

•Coagulase: an enzyme that clots blood and is an important diagnostic marker used to differentiate S. aureus from other staphylococci • Hyaluronidase: digests hyaluronic acid which comprises the basement membrane found in tissue. Also known as spreading factor. • Staphylokinase: digests blood clots. • Lipase: digests lipids and oils, allowing bacteria to more easily colonize the skin. • Penicillinase & other antibiotic-resistance enzymes (MRSA): inactivates penicillin and other beta-lactam drugs.

Mycobacteria genus

•Gram positive, irregular shaped bacilli • Often long and filamentous • Acid-Fast Bacilli (AFB) distinguished by complex cell walls containing mycolic acids and waxes. • Strict aerobes that grow well on simple nutrients and media, albeit very slowly compared to other bacteria. 2 Species of Medical Importance: • Mycobacterium tuberculosis • Mycobacterium leprae

S. aureus exotoxins

•Hemolysins: lyse erythrocytes (RBCs) • Leukocidins: lyse white blood cells • Enterotoxins: exotoxins that act upon the gastrointestinal tract of humans which induce nausea, vomiting, and diarrhea • Exfoliative toxin: separates the epidermal layer from the dermis and causes the skin to peel away. • Toxic shock syndrome toxin (TSST): causes severe systemic effects including fever, vomiting, rash, and shock

Systemic streptococcus pyogenes diseases

arise from possible complications of a strep throat infection GROUP A Scarlet Fever: Infection with a lysogenic strain(bacteria that have phages inside of them) of Strep. pyogenes carrying a prophage can release erythrogenic toxin causing a systemic bright red rash over the body (scarlatina) and strawberry tongue. Rheumatic Fever: If bacteria enters the bloodstream, it can attach to and damage heart valves, leading to heart murmurs and heart disease.

What is the surface antigen that is only found on Group A strep?

M protein w/ fimbriae

Salmonella typhi

(ABROAD)• The most serious pathogen in the genus Salmonella. • Etiological agent of Typhoid Fever • Humans are the only host and reservoir • Feces-contaminated food or water is ingested and motile bacilli attaches to intestinal cells • Gradual onset of headache, loss of appetite, lethargy and fever, with abdominal pain followed by a few short bouts of diarrhea after the second week. • Disease can lead to perforations in the small intestine leading to death

Salmonella enterica

(US)About 2,500 serotypes (including S. enteritidis and S. typhimurium) • Normal animal intestinal flora (cows, chickens, rodents, reptiles) • Transmission mainly from raw poultry or eggs, reptilian pets, or raw milk. • One of the leading causes of gastroenteritis • Bacteria is ingested and they invade small intestine epithelial cells • Usually self-limiting in the healthy, causing fever and an inflammatory but watery diarrhea with abdominal pain, nausea and vomiting.

Major Hepatitis Viruses

-5 major viruses -HBV and HCV can cause cancer

common opportunistic infection in Aids patients

-AIDS wasting syndrome, chronic diarrhea -CMv Retinitis -mycobacteria and pneumocystis pneumonias -neurodegenerative diseases -candidiasis -kaposi's sarcoma

Enterococcus

-Enterococcus faecalis and other species (mostly Enterococcus faecium) are found in large numbers in the large intestine as part of the normal microbiota (flora). -Enterococcus possess Lancefield Group D cell wall antigens and originally were classified as Group D streptococci. -Enterococci colonize the GI tract of humans and animals -Cause opportunistic infections of the urinary tract, from wounds, and bacteremia -Most infections arise endogenously from the patient's own intestinal flora -At risk are patients who have been: - hospitalized for prolonged periods - treated with broad spectrum antibiotics to which enterococci are resistant (VRE).

Toxigenic S. aureus Diseases

-S. aureus diseases associated with exotoxins production -acute vomiting= 1-6 hours post ingestion of contaminated food Food Intoxication: caused by heat stable enterotoxins produced by the bacteria. Associated with foods rich in carbohydrates like cream pastries, potato salad, also ham and processed meats. Scalded Skin Syndrome: bacteria grows on skin surface and secretes exfoliative toxin causing upper skin layer separation. Toxic Shock Syndrome: severe systemic infection due to TSST. First identified through tampon use. Causes fever, vomiting, rash and shock.

acute GI symptoms is about

1-6 hours post ingestion

Staohylococcal disease can be classified into:

1. local pyogenic infections(boils) 2. systemic infections(osteomyelitis) 3. toxigenic infections(scalded skin syndrome)

Curved Gram negative bacilli

3 Genera of Medical Importance: -Vibrio: Comma-shaped rods with a single polar flagellum -Campylobacter: Short spirals or curved rods with one flagellum -Helicobacter: Tight spirals and curved rods with several polar flagella

True pathogenic Escherichia coli strains

All are spread via fecal-oral route, from poor sanitation and fecal contamination. • Enterotoxigenic E. coli (ETEC): Non-invasive but forms enterotoxins which stimulate secretion & fluid loss causing severe watery diarrhea. • Enteroinvasive E. coli (EIEC): Invades the large intestinal wall and causes inflammatory disease leading to bloody diarrhea. • Enterohemorrhagic E. coli (EHEC): most common Strain O157:H7 has fimbriae that adhere to the intestinal wall and releases toxins causing severe bloody diarrhea, hemorrhagic syndrome & severe kidney damage. - Examples include: O157:H7 and O121, O26 -Found in food or water contaminated by cattle feces (mainly hamburger). -Person-to-person transmission also occurs. -<100 cells needed for infection.

T/F virus cause pus formation

FALSE only BACTERIA can form pus

The Genus Bacillus

Gram-positive, endospore-forming, motile rods Mostly saprobic Aerobic and catalase positive Versatile in degrading complex macromolecules Source of antibiotics Primary habitat is soil 2 species of medical importance: Bacillus anthracis Bacillus cereus

Localized Strep. pyogenes infections

Group A Impetigo: associated with epidemics among schoolchildren. poor hygiene Erysipelas: infection in the dermis caused by a deeper wound or incision. Rash is very red and hot! Streptococcal Pharyngitis: (Strep Throat) • Multiplies in the tonsils or pharyngeal mucous membranes. • Causes redness, edema, extreme tenderness with painful swallowing and accompanied by fever and headache. • Other signs include a purulent exudate (pus) over the tonsils. very horrid breath because of formation of pus

Gonorrhea Diagnosis

Microscopy: A Gram stain of a male urethral swab or from specimens taken from the cervix, urethra or rectum of the female reveals intracellular Gram (-) diplococci in WBCs. • ~500,000 new cases of gonorrhea occur every year in the U.S. • Prior infection does not provide long lasting immunity.

The Genus Clostridium

Morphology: • Gram positive, endospore-forming rods, terminal round or ovoid spores • Anaerobic with spores that will only germinate under anaerobic conditions • Catalase negative (unlike the genus Bacillus) • Saprobes in the environment and some are commensals of humans and animals 4 Species of Medical Importance: -Clostridium tetani -C. perfringens -C. botulinum -Clostridium difficile

Clostridium tetani and Tetanus treatment

Immediate antitoxin therapy with human tetanus immune globulin (TIG) patients may require a respirator and a tracheostomy

Neisseria

Morphology: -Neisseria are aerobic, Gram (-) diplococci with flattened adjacent sides. - Non-spore forming and lack flagella - Most species are generally non-invasive (but are opportunistic) and colonize the mucous membranes and skin. - Pathogenic Neisseria are strict parasites and have capsules and fimbriae as main virulence factors. • They are very fastidious, nonhemolytic, and require complex media for growth. • The bacteria may be cultured on Chocolate Agar which contains heated blood and/or hemoglobin for enrichment (just dry blood) • Selective Media is ThayerMartin Agar (contains 3 antibiotics that inhibit other microbes from growing) • There are two primary pathogenic species of Neisseria: -Neisseria gonorrhoeae -Neisseria meningitidis

Bacillus anthracis

Morphology: • Large, block-shaped rods • Have central endospores with streptobacilli arrangement Virulence Factors: • Unique polypeptide capsule that is immunogenic and antiphagocytic • Anthrax exotoxin which causes edema, cell death (necrosis) and tissue destruction

Hepatitis Viruses

Now Includes Hepatitis D (HDV) and Hepatitis E (HEV)

Other Vibrio pathogens

Salt-tolerant (halophilic) inhabitants of coastal waters, associated with marine invertebrates Vibrio parahaemolyticus: • Acute gastroenteritis from eating raw, partially cooked, or poorly stored seafood • Fish, squid, shrimp, lobster, crabs, oysters, clams • Explosive diarrhea from enterotoxins but less severe than cholera Vibrio vulnificus: • Acute gastroenteritis from contaminated seafood, especially raw oysters • Can develop serious necrotic cellulitis from shucking contaminated oysters or any skin penetration from contaminated water.

HIV Infection

So here's the lifecycle of HIV right so it's going to bind via GP120 your CD4 cells. Okay, along with the co receptor its then going to use GP41 to fuse into the host cell then you're going to encode and then the RNA is going to be made into a DNA copy using reverse transcriptase. And then the reverse transcriptase will allow the viral RNA to not have DNA copies of it so here's HIV DNA. Then integrase will take the HIV DNA and integrated into your chromosomes, so now it becomes a permanent part right now, you have latency, you have a pro virus it's now inside of your chromosomes permanent right so then now that you have this HIV genome into your chromosomes. your cells going to start making HIV proteins. And you're gonna start assembling the HIV virus and then the virus will use protease to start cutting it's proteins properly. To then insert their viral Spikes on to your cell membrane and then you're going to have budding so this protease is very important to kind of chop up and make their protein become functional so you can make new viruses that way that one just brought out.

Yersinia pestis and the plague

There are 3 forms of Plague Bubonic Plague: • Plague bacilli multiply in flea bite, enters lymph node to form a painful, rapidly enlarging bubo. • Also causes fever, chills, headache and nausea. Septicemic Plague: Progression to massive bacterial growth in blood leading to coagulation and tissue destruction causing necrosis - the Black Death Pneumonic Plague: Infection is localized to lungs and is highly contagious through inhaled droplets. Fatal if left untreated.

Opportunistic Enterobacteriaceae

These bacteria cause infection when host defenses fail or during medical procedures (nosocomial) Klebsiella pneumoniae: • Pneumonia occurs primarily in patients with underlying pulmonary disease or alcoholism • Klebsiella UTIs occur in patients with urinary catheters. • Can also cause meningitis, bacteremia, & wound infections Serratia marcescens: Causes pneumonia, particularly catheterassociated bacteremia, UTIs, and wound infections Enterobacter, Citrobacter: Mostly associated with urinary tract infections

S. aureus virulence factors

Various S. aureus strains exhibit a great variety of virulence factors, with no single toxin or enzyme completely responsible for the virulence seen in the species. Protein A forces antibodies to bind backwards with the Fc region instead of variable region...when they bind the wrong way, it does not trigger to correct immune response

Secondary Syphilis

Weeks to months after the chancre heals • Still contagious! • Systemic infection resulting in body rash (palms and soles of feet), fever, headache, wart-like growths (condylomata lata) in genital areas and swollen lymph nodes

Claustridium botulinum

Worldwide spore forming anaerobe that commonly inhabits soil and water and the intestinal tract of animals • Under anaerobic environments, vegetative cells release the most potent microbial toxin - Botulinum Toxin • Botulism is an intoxication usually associated with eating canned or preserved foods, though it can occur as a result of infection. • 3 types of Botulism: • Botulinum Food Poisoning • Infant Botulism • Wound Botulism

Lepromatous Leprocy

a deeply nodular infection that causes severe disfigurement of the face and extemities

Streptococcus pneumoniae

aka Pneumococcus • A significant human pathogen that causes 60-70% of all bacterial pneumonias and a main cause of bacterial meningitis. • Small, lancet-shaped cells in pairs (diplococcus) or short chains. • Humans are the principal reservoir carrying the pneumococcus in their nasopharynx. • The major virulence factor is a pronounced capsule, present in all pathogenic strains of Strep. pneumoniae • 90 different capsular types have been identified using the Quellung Test (a capsular swelling test using antiserum specific for a particular capsule type) • Available subunit vaccines target these capsular strains: Prevnar 13 for infants and Pneumovax 23 for adults and older

Neisseria gonorrhoeae

aka gonococcus because it is the etiological agent of gonorrhea. Top 5 STDs • Strictly a human infection • Does not survive more than 1-2 hours on fomites • Infection is asymptomatic in 10% of males and 50% of females -Does grow on Thayer-Martin agar

Clostridium tetani and Tetanus prevention

an effective DTap vaccine containing tetanus toxoid booster shot (Tdap) is recommended every 10 years.

Clostridium botulinum and Botulism treatment

antitoxin available that must be administered early for greatest effectiveness patients are managed with respiratory and cardiac support systems

Bordetella pertussis

• A very small, encapsulated Gram (-) coccobacillus • A uniquely human pathogen • Etiological agent of Whooping Cough, a communicable childhood disease that causes an acute respiratory syndrome. • Transmission by contact with airborne droplets created by coughing or sneezing, or direct contact with discharge. • Vaccine is available (DTaP) that contains pertussis toxoid and other antigens. Booster shots are recommended at ages 10-18 years. Virulence: • Adhesins and toxins are the primary mediators of the disease. • B. pertussis attaches to ciliated respiratory epithelium through adhesins (filamentous hemagglutinin, pertussis toxin) to inhibit and then kill these cells. -The loss of the ciliary mechanism leads to a buildup of mucus and blockage of the airways. This leads to fits of abrupt, hacking coughs followed by a deep inhalation that produce a "whoop" sound. -Cough in unvaccinated individuals is so severe that it frequently leads to aspiration pneumonia, eye hemorrhages, hernias, tongue ulcers and seizures.

Viruses & Viral Diseases

• A virus is a small, acellular, infectious particle. • A virus is also an obligate intracellular parasite. • Viruses are limited to a particular host or cell type. • Viral infections range from very mild to life-threatening. • Many viruses are strictly human in origin, others require transmission by zoonotic vectors. • Most DNA and a few RNA viruses can become permanent residents of the host cell. - Latent infections - Chronic infections - Oncogenic • Several viruses can cross the placenta and cause congenital defects. Certain viruses are also considered teratogens - agents that cause birth defects or kill the embryo outright.

Pasteurella multocida

• A zoonotic pathogen that is normal oral flora in many animals • Causes opportunistic human infections • Transmitted via animal bites or scratches and causes cellulitis and a local abscess that can spread to joints, bones, and lymph nodes. • Pasteurella has adapted to the nasopharynx of the household cat and most U.S. cases result from cat bites.

Yersinia pestis

• A zoonotic pathogen • Short bacilli with bipolar staining • Etiological agent of the Plague • Small rodents serve as reservoirs and fleas act as biological vectors • Virulence Factors: - Capsule - Coagulase - Exotoxins (cause tissue necrosis) In the U.S., wild rodents (especially prairie dogs and rabbits) are the reservoir in the southwest desert.

Leptospira interrogans

• A zoonotic spirochete - primarily an animal disease transmitted accidentally to humans • Transmission via indirect contact with urine from infected animals • Animals shed bacteria in their urine and contaminate water • Portal of entry in humans is mucous membranes and abraded skin. • Principal targets are the kidneys, liver, brain and eyes. • Causes jaundice, fever, kidney damage, meningitis, neurological problems. Leptospirosis is an occupational hazard of: • Sewer Workers • Dairy Farmers • Veterinarians • Slaughterhouse workers • Military personnel • Livestock workers • Rice Farmer Incidence increase during natural disasters (hurricanes) and heavy rains

Borrelia burgdorferi

• A zoonotic spirochete that is transmitted by ticks • Etiological agent of Lyme Disease • The most common vector-borne disease in the United States (30,000 reported cases per year but estimated at ~300,000 cases per year) • Complex lifecycle involving mice and deer

Vibrio cholerae and Cholera

• After being ingested, V. cholerae must pass through the acid environment of the stomach, thus it requires a high infectious dose (1 million cells) to establish infection. • Infects surface of small intestine (non-invasive) • Virulence is due to an enterotoxin called Cholera Toxin that causes massive electrolyte & water loss through secretory diarrhea, causing severe dehydration leading to muscle, circulatory, & neurological problems • Cholera: Profuse, watery diarrhea with mucous flecks ("rice-water stools"). • Fluid loss is so great: nearly 1 liter per hour in severe cases; can lose up to 50% of body weight during the course of the disease. • Treatment involves replacement of water and electrolytes, along with antibiotics. • Prevention: proper sewage disposal and water purification; vaccine available for travelers

Viridians Group Disease

• Although normal oral cavity flora, they are opportunistic and associated with: -Dental Caries & Tooth Abscesses -Subacute Endocarditis: bloodborne bacteria settle and grow in inner heart lining and valves -Bacteremia, meningitis, and abdominal infection

Influenza Virus

• An Orthomyxovirus - Enveloped, helical capsid, segmented ssRNA genome an RNA virus • Etiological agent causing Influenza (Flu) • 3 Influenza virus types - Influenza A (Epidemics & Pandemics) - Influenza B (Epidemics only) - Influenza C (Minor respiratory illness) • 2 important envelope glycoprotein spikes - Hemagglutinin (HA): binds to host cell - Neuraminidase (NA): assists in viral budding and release • Influenza subtypes based on H & N combinations, eg. H1N1, H3N8

Kaposi's Sarcoma-associated Herpes Virus (HHV-8)

• An STD that infects B cells • Has been isolated from Kaposi's sarcoma, a common tumor in AIDS patients. -wont flare up unless you are severely immunocompromised

Congenital Syphilis

• Any child born to mothers with untreated or inadequately-treated syphilis. • Occurs in the fetus of an infected pregnant woman in primary and secondary stages. Acquired through transplacental dissemination. • Newborns often demonstrate such signs as nasal discharge ("snuffles"), peeling skin rashes on hands and feet, bone deformities. • Children with late stage congenital syphilis develop teeth malformation, blindness and deafness

Variola virus & Smallpox

• At one time, smallpox was ranked as one of the deadliest infectious diseases, leaving no civilization untouched. • Through the efforts of the World Health Organization, it became the first disease to be eliminated by vaccination. The last case of smallpox was seen in 1977. • Strictly a human pathogen • Transmission was through inhalation or direct skin contact. • Infection associated with fever, malaise, severe headache, & a vesicular rash throughout the body • Variola major - highly virulent, caused toxemia, shock, and intravascular coagulation • Variola minor - less virulent

Rickettsia prowazekii & Epidemic Typhus

• Bacteria enter endothelial cells & cause necrosis of the vascular lining • Results in high fever, rash (spreads from chest to extremities), joint and muscular pain. Can be complicated by personality changes, hypotension and gangrene. • Historically present in areas of war, poverty, and famine.

Shigella

• Etiological agent of Bacillary Dysentery - a disease marked by crippling abdominal cramps and frequent diarrhea with mucus and blood. • Important species are S. dysenteriae (severest form), S. boydii and both S. sonnei and S. flexneri (found in U.S.) • Only found in human and ape gastrointestinal tract • Transmission through fecal-oral spread • Feces-contaminated food or water is ingested and the nonmotile Shigella is phagocytosed into the large intestines where they survive in the phagosome and multiply. • They spread to adjacent cells and stimulate an inflammatory immune response that causes extensive tissue destruction. • Also releases endotoxin & exotoxins (Shiga toxin) • Shiga toxin cleaves the 60S ribosome, inhibiting protein synthesis.

Mycobacterium leprae

• Etiological agent of Leprosy • Called Hansen's Bacillus • Strict parasite that has not been grown in artificial media or human tissue cultures • Slowest growing of all species and multiplies in host cells • Endemic in regions throughout the world • Not very contagious and mechanism of transmission is poorly understood. Spread through direct contact. • Multiplies in macrophages in the skin and spreads to nerves. • 2 Forms of Leprosy: -Tuberculoid Leprosy -Lepromatous Leprosy

Varicella-Zoster Virus (VZV) 3

• Etiological agent of Varicella (commonly known as Chickenpox) and a recurrent infection called Herpes Zoster (Shingles). • Extremely communicable and transmitted mainly via respiratory droplets but also skin contact. • The virus replicates in the respiratory mucosa (incubation of 10-20 days) and then travels through the bloodstream and spreads throughout the body. • Primary Infection - Chickenpox - Fever and a vesicular (fluid filled) itchy rash - Virus enters neurons (dorsal root ganglia) and remains latent A live, attenuated Varicella vaccine is available. • Secondary infection - Shingles • Reactivation of the virus results in Herpes Zoster (Shingles) with vesicles localized to distinctive areas • Reactivation by such stimuli as X-Ray treatments, immunosuppresive and other drug therapy, surgery, stress • Very painful and tender • Can cause Chicken Pox in newly infected individuals

Neisseria gonorrhoeae virulence factors

• Fimbriae: provide adhesion to mucosal membranes • IgA Protease: Destroys the IgA secretory antibody on host mucosal surfaces. • Capsule: (blocks phagocytosis by macrophages and neutrophils) • Endotoxin: (highly toxic; referred to as LOS instead of LPS) Transmission is through sexual contact or extragenital inoculation

Corynebacterium diphtheriae

• Gram positive, non-spore forming bacilli • Irregular shaped and pleiomorphic (club-shaped or palisade arrangement) • Non-motile and grows best in oxygen • Corynebacterium are ubiquitous in plants and animals and colonize the skin and mucous membranes of humans. • C. diphtheriae only has human reservoirs, with respiratory spread. • Etiological agent of Diphtheria which is no longer a significant cause of illness in the United States due to successful vaccination with DTap vaccine. • Most cases occur in non-immunized children from 1-10 years of age. 2 Stages of Disease: • Local, primary infection in the upper respiratory tract (pharynx, tonsils, larynx, and trachea) • Toxin production and toxemia -Virulence is due to Diphtheria exotoxin which is only produced by lysogenic strains of Corynebacterium (infected by a bacteriophage carrying the exotoxin gene). -Toxin causes exudative pharyngitis which evolves into a thick, dirty white pseudomembrane (composed of dead cells, fibrin, bacteria, lymphocytes and gray pigment), which is difficult to remove without damaging tissues. -The membrane can obstruct the airway and cause suffocation. • Diptheria toxin can diffuse into the neck tissue and produce edema so that the patient appears "bull necked". • Bacteria do not invade deeper than the epithelial tissues but toxin is absorbed and disseminated, e.g., diphtheria toxin damages the heart and causes myocarditis and cardiac dysfunction. • Death can occur from respiratory obstruction or cardiac failure. Treatment: Antibiotics and Diphtheria antitoxin

Listeria monocytogenes

• Gram positive, non-spore forming rods • Short bacilli (coccobacilli) with flagella • They are facultative anaerobes that grow in acidic conditions, high salt and a wide temperature range (1 to 45°C - includes cold growth, which is rare in pathogens). • Primary reservoir is soil and water but animals, plants, and food are secondary sources of infection. • Listeriosis is infection with Listeria causing gastroenteritis resulting in food poisoning from eating refrigerated foods, particularly unpasteurized milk and soft cheeses, deli meats, unwashed fruits and vegetables. • Listeria can cross the placenta or infect babies during delivery, causing neonatal septicemia and meningitis.

HIV Transmission

• HIV is spread only by direct and rather specific routes • Blood • Semen • Vaginal Fluids • HIV can also be isolated from the following • Urine • Tears • Sweat • Saliva • Men having sex with other men (a group labeled MSM) have increased susceptibility because of the practice of anal sex, which is known to lacerate the rectal mucosa and can provide an entrance for viruses from semen into blood.

The Spirochetes

• Have a typical Gram (-) cell wall • Possess a well-developed periplasmic space that encloses the flagella (called an endoflagella) • Helical shape with numerous coils •All are motile with endoflagella flexing and spinning along the axis • Majority are free-living saprobes or commensals of animals 3 Pathogenic Genera of Spirochetes: • Treponema • Leptospira • Borrelia

Viral Hepatitis

• Hepatitis - an inflammatory disease of liver cells that may result from several viruses • Interferes with liver's excretion of bile pigments such as bilirubin into the intestines. Bilirubin accumulates in blood & tissues causing jaundice (main symptom), a yellowing of the skin and eyes. • Caused by several unrelated viruses

Treponema pallidum

• Humans are the natural host • Extremely fastidious and sensitive. Cannot survive for long outside of the host • Causes Syphilis, a major worldwide STD Transmission: • Sexual Contact- direct contact with mucous membranes or abraded skin. Hooked tip of the spirochete binds to epithelium before entering the bloodstream. • Congenital (Crosses the placenta) • Blood transfusion

Chlamydia trachomatis

• Humans are the reservoir • Body secretions carry the elementary bodies to mucous membranes 3 main pathogenic serotypes of Chlamydia trachomatis • A - C which cause Ocular Trachoma • D - K which cause genitourinary infections and inclusion conjunctivitis • L1 - L3 which cause Lymphogranuloma venereum

Clostridium difficile

• Normal resident of the colon that is usually present in low numbers (Present in 2-5% of the adult population). • Nosocomial infection is common. • Overgrowth of C. difficile in the gastrointestinal tract is often associated with antibiotic use. • Causes antibiotic-associated (or pseudomembranous) colitis. • It is now the second most common intestinal disease after salmonellosis in industrialized countries. • Superinfection with C. difficile leads to release of exotoxins which lead to diarrhea, inflammation and intestinal damage giving rise to pseudomembranous colitis. Severe cases leading to death arise from intestinal perforation. • Highest risk group: Nursing home patients • Treatment: Removal of antibiotics in uncomplicated cases, stronger antibiotics for severe cases, and fecal transplantation therapy.

Chlamydia

• Obligate Intracellular Gram (-) Parasites • Alternate between 2 Stages: - Elementary Body (EB) - Reticulate Body (RB) • EB is the infectious stage taken into phagocytic vesicles by the host cell • In the phagosome, EB develops into a RB. • RB is the noninfectious but metabolically active and dividing stage. • Mature RBs reorganize into EBs and are released from the cell to infect new host cells. -Doesn't grow on Thayer-Martin agar

Influenza Surveillance & Preparation

• Observe pig, bird, and human populations. • Make a "best guess" for flu vaccines. Exact strains are reviewed annually in relation to the strains circulating in the last year. Usually, one or two of the strains in the vaccine are changed each year. 2020-2021 Flu Vaccine (Quadrivalent) • A/Guangdong/2019 (H1N1)-like virus • A/Hong Kong/2671/2019 (H3N2)-like virus •B/Washington/02/2019-like virus •B/Phuket/3073/2013-like virus • Reduce transmission from birds to humans and pigs to humans. New flu strains often start in Asia, where people live close to their pigs and chickens.

infant botulism

• Occurs most frequently in infants less than 1 year old. Is the most common form of botulism in the USA. • The infant ingests spores in dust or honey. The immature GI tract flora permits spore germination and growth of vegetative cells. • Symptoms include constipation, generalized weakness, weak crying, poor feeding, lethargy, loss of head control (floppy baby syndrome), and possible respiratory arrest.

Legionella pneumophila

• Pleomorphic Gram (-) Rods • Aquatic organism found intracellularly in amoebas • Widely distributed in water and found in water supplies, air conditioners, cooling tanks, hot water heaters. • Acquired by inhaling aerosols containing Legionella • Causes Legionnaire's Disease - pneumonia, headache, fever, diarrhea and nonproductive cough. Occurs mostly in older people debilitated by diabetes, alcoholism, smoking, or immunocompromised. • A less severe form of the disease is called Pontiac Fever and does not lead to pneumonia and rarely causes death.

Streptococcus pneumoniae and Pneumonia

• Pneumococcus in the nasopharynx can gain entry to the lower respiratory tract if compromising factors are present that impair mucociliary motion, cough reflex, etc. (viral respiratory infection, severe allergy, alcoholism) • Once in the lungs, the bacteria can evade non-specific immune defenses such as phagocytosis because of its large capsule.

Cytomegalovirus (CMV) 5

• Produces "giant cells" with nuclear & cytoplasmic inclusions called "owl's eye" • Very ubiquitous human pathogen • Transmitted in saliva, respiratory mucus, breast milk, urine, semen, cervical secretions & feces. • Can cross the placenta and is the most common cause of congenital infection in the U.S (causing mental retardation and hearing loss). • CMV is commonly carried in a latent state in various tissues. you can only get it once: life immunity. • Most infections are asymptomatic but can cause cytomegalovirus mononucleosis similar to EBV. • Groups that may develop a more virulent form of the disease include newborns and AIDS patients who can develop fever, severe diarrhea, hepatitis, pneumonia, blindness and death.

Rickettsia rickettsii & RMSF

• R. rickettsia infects the endothelium of the vasculature causing a spotted rash which results from the leaking of RBCs from dilated blood vessels. • The rash has a centripetal spread: starts on the extremities (palms and soles) and then moves inward to the trunk of the body. Rash accompanied by fever. • Necrotic lesions may occur from the rash and in more serious and complicated cases, pinpoint hemorrhages may result in major organs leading to permanent central nervous system damage, pneumonitis, cardiac problems and death.

Gastrointestinal Anthrax

• Rare but deadly condition. • Spores enter via ingestion. • Follows consumption of contaminated meat, causing acute inflammation of the gastrointestinal tract. • Causes nausea, fever, abdominal pain, vomiting of blood, and severe diarrhea. • 50% mortality rate if untreated. 60% survival rate with treatment

Enterobacteriaceae family

• Small Gram negative rods • Facultative Anaerobes • Catalase positive • Many inhabit soil and water & some are common occupants of the large intestine • The enteric pathogens are frequent causes of diarrheal illnesses through the action of their enterotoxins Divided into: - Fecal Coliforms (Lactose Fermenters) - Non-Coliforms (Non-Lactose Fermenters)

Pseudomonas aeruginosa

• Small, Gram (-) Rods • Highly motile with a single polar flagellum • Ubiquitous in soil and water • Grows on most media and has a highly versatile metabolism • Resistant to soaps, dyes, quaternary ammonium disinfectants, drugs, drying • A major nosocomial and opportunistic pathogen • Reservoirs - Water (faucets, drains), respiratory equipment, raw vegetables, flowers, and slimy bar soap. • Produces greenish-blue pigment: Pyocyanin & Pyoverdine • Cultures produce fruity, grape-like odor Virulence Factors: • Endotoxin (LPS) • Polysaccharide slime layer that is antiphagocytic and involved in biofilms • Exotoxins that degrade host tissues Often multidrug resistant so testing is essential Infections in healthy people: Skin Rashes & Wound Infections, Hot Tub Folliculitis & Swimming Pool infections (green pus) & infections in burn patients Main killer of Cystic Fibrosis patients

Wound botulism

• Spores enter a wound or puncture much as in tetanus, but the symptoms are similar to those of food-borne botulism. • Increased cases are reported in injection drug users. Botox Cosmetic Treatment: • Super-diluted botulinum toxin is injected into wrinkled areas to create controlled muscle weakening. • Toxin wears off so repeat injections are given every 4-6 months.