Microbiology, Ch 21, Nester's 9th

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Klebsiella Pneumonia

- Enterobacteria such as Klebsiella sp. and other Gram negative rods can cause pneumonia, especially if host defenses are impaired - Klebsiella sp. common hospital-acquired pathogens, cause most of the deaths from healthcare-associated infections Signs/Symptoms: - 1-3 day incubation - cough, chills, SOB, fever, chest pain and cyanosis - same as for penumococcal pneumonia - chills are repeated chills and a thick, bloody, JELLY-LIKE sputum Causative Agent: - Klebsiella pneumoniae - G- rod with large capsule that produces mucoid (mucusy) colonies - common part of normal microbiota in GI tract and my be sound in mouth or throat Pathogenesis: - person-to-person contact through secretions (contact or inhalation) or from medical equipment like ventilators - first colonize throat, then to lungs via inhaled air or mucus - adhesins aid in colonization - virulence factors: - capsule - interferes with opsonin C3b - sidiophore - high affinity for Fe, quickly grabs up the cell's iron. The iron depletion acts as a celluler stressor that induces inflammation and ehances the spread of bacteria. - klebsiella bacteria results in more tissue damage than does pneumococcal pneumonia and in the rapid formation of LUNG ABSCESSES. - means even if meds work the damage to lungs may be permanent and the perosn may still die. - infeciton can spread through the blood, causing abscesses in other tissues, like liver/brain or causing septic/endotoxic shock. Epidemiology: - Klebsiella is widespread in nature and common in normal microbiota. People who get this pneumonia are very old/young or have a comprommised immune system - strains that circulate in hospitals/nursing homes are often resistant to antimicrobials and more are becoming multi-drug resistant Tx/Prevention: - treat with antibiotics - drug sensitivity testing to figure out which ones - seriously ill? Immediately give combination antibiotic therapy - surgery to drain abscesses - tx is challenging - strains becoming multi-drug resistant Most have plasmids: β-lactamase (resist β-lactams such as penicillin); many also extended-spectrum lactamase (ESBL) (resist many cephalosporins) - fatality rate can reach 50% - No specific preventative measures like vaccination - prevent spread by following infection control measures (gown, glove, wash hands), disinfect environment, use sterile respiratory equipment and give antibiotics only when you have to control but avoid development of resistance.

T/F - "Flesh-eating" Streptococcus pyogenes is considered a newly emerging disease.

False

The causative agent of the pneumonia that results in permanent lung damage, may be nosocomial, and has a high mortality if untreated is: A) S. pneumoniae. B) K. pneumoniae. C) S. pyogenes. D) S. aureus. E) M. pneumoniae.

K. pneumoniae. Klebsiella pneumoniae - G- rod with large capsule and makes large, mucoid colonies when grown on agar.

Which antibiotics may be completely ineffective in treating a mycoplasmal infection? A) Penicillin AND tetracycline B) Penicillin AND cephalosporin C) Tetracycline AND cephalosporin D) Cephalosporin AND erythromycin E) Erythromycin AND tetracycline

Penicillin AND cephalosporin Both work against the cell wall, mycoplasma has no cell wall.

Both S. pneumoniae and K. pneumoniae use this as a virulence factor. A) Pili B) Flagella C) Capsules D) Cilia E) Toxins

capsule

The resistance of Klebsiella to antibiotics may be: A) chromosomal mediated AND lysosomal mediated. B) plasmid mediated AND lysosomal mediated. C) chromosomal mediated AND plasmid mediated. D) lysosomal mediated AND capsule mediated. E) capsule mediated AND plasmid mediated.

chromosomal mediated AND plasmid mediated. Most have plasmids: β-lactamase (resist β-lactams such as penicillin); many also extended-spectrum lactamase (ESBL) (resist many cephalosporins) Capsule is about resistance to being engulfed by phagocytes. No lysosomes. Phagocytes have lysosomes. Resistance can be due to spontaneous nucleic acid mutations or conferred by plasmids. So that one.

Two relatively widespread North American lung mycoses are A) candidiasis and coccidioidomycosis. B) candidiasis and aspergillosis. C) aspergillosis and Reyes syndrome. D) coccidioidomycosis and histoplasmosis. E) None of the choices is correct.

coccidioidomycosis and histoplasmosis

The common cold - Causative Agent:

- 30-50% caused by the 100+ types of human RHINOVIRUSES - family Picornaviridae - group of naked ssRNA viruses - can be grown in culture - in live cells at 33C and slightly acidic pH (conditions mimic upper respiratory tract) - inactivated if pH drops below 5.3 (too acidic) - so destroyed in the stomach - many other viruses (like some adenoviruses and coronaviruses) can produce signs/symptoms of the common cold

Why do some otitis media cases not respond to antibiotic treatment? - Most cases are caused by bacteria that are resistant to commonly prescribed antibiotics. - About 30% of cases are caused by respiratory viruses—antibiotics do not help these cases. - Otitis media is caused by viruses that constantly undergo antigenic shift and/or antigenic drift. - The bacterial causative organisms mutate frequently, changing their antibiotic target sites. - Unless the exact causative organism is identified, it is impossible to prescribe the correct antibiotic.

- About 30% of cases are caused by respiratory viruses—antibiotics do not help these cases. p.535 "about 1/3 of cases are caused by RESPIRATORY VIRUSES, explaining why sonme infections do not respond to antibiotics, which have no effect on viruses."

Adenovirus Respiratory Tract Infections -

- Adenoviruses are widespread, cause a dif types of infection depending on the viral serotype. - some cause a sore throat, others eye infections Adenoviruses are representative of the many viruses that cause upper respiratory tract infections characterized by FEVER. Symptoms look much like the common cold but with FEVER - 5-10 days after infection, sore throat, pus on pharynx and tonsils - is why this can be CONFUSED WITH STREP THROAT. - Lymph nodes large/tender, mild cough maybe. - Conjuntivitis and diarrhea maybe. - if severe cough with chest pain, can be mistaken for Pnuemonia - recovery in 1-3 wks

Diphtheria is an acute contagious disease caused by an exotoxin that: - functions by inhibiting protein synthesis. - may cause destruction of cardiac, kidney and nerve tissues. - can be neutralized as a result of immunity produced by the DTaP vaccine. - All of the choices are correct.

- All of the choices are correct.

Legionella pneumophila may be found in: - soil and aquatic ecosystems. - air-conditioning systems. - shower stalls. - All of the choices are correct.

- All of the choices are correct.

The exotoxin produced by Corynebacterium diphtheriae: - causes an inflammatory response. - causes the formation of a pseudomembrane on the respiratory mucosa. - may destroy cardiac and kidney tissue. - All of the choices are correct.

- All of the choices are correct.

Which of the following drug(s) is(are) used to treat tuberculosis? - Isoniazid - Ethambutol - Pyrazinamide - All of the choices are correct.

- All of the choices are correct.

Which of the following is prevented by the DTaP vaccine? - Diphtheria - Whooping cough - Tetanus - All of the choices are correct.

- All of the choices are correct. D- diphtheria - toxoid T - Tetnus - toxoid aP - acellular (subunit) Pertussis

All of the following are examples of fixed macrophages EXCEPT: - Kupffer cells. - alveolar macrophages. - microglia. - All of these are examples of fixed macrophages

- All of these are examples of fixed macrophages Ch 14 again. - liver - lungs - brain

Adenoviruses - Prevention/Tx:

- As with colds, no specific tx for adenoviruses, most patients recover on their own - if secondary bacterial infections occur ->antibiotics - available is an orally given attenuated vaccine against 2 serotypes most likely to cause severe disease but only given to Military recruits

How can Streptococcus pyogenes initially be differentiated from other Streptococcus species that form part of the throat normal microbiotia? - By Gram staining—it is a Gram-positive organism. - By culturing the bacteria on nutrient agar and checking for hemolysis. - By morphology—the bacteria are spherical and grow in long chains. - By detection of the "A" carbohydrate in its cell wall using antibodies. - By specific disease signs and symptoms, including sore throat and fever.

- By detection of the "A" carbohydrate in its cell wall using antibodies. p.537. The organism can be differentiated from other streptococci that normally inhabit the throat by its colony morphology on blood agar - S. pyogenes colonies are surrounded by a characteristic clear zone ob beta-hemolysis. Mos species of Streptococcus that are typically part of the normal throat microbiota are either alpha-hemolytic or non-hemolytic. A few other streptococci are beta-hemolytic too though so what else? S. pyogenes is commonly referred to as GAS - Lancefield grouping uses antibodies to distinguish the cell wall carbs in streptococcal species and S. pyogenes is characterized by the "A" carb in its cell walls. That's why this answer and not the second one.

What is the most likely reason why smokers are more at risk for respiratory system infections? - Cigarette smoke is carcinogenic (cancer-causing), leading to a much higher incidence of lung cancer. - They aren't; this is just a rumor used to get people to stop smoking. - Smokers take in microbes from their hands into their lungs as they handle cigarettes and inhale the smoke. - Tobacco contains viruses that are inhaled when a person smokes; these cause respiratory infections. - Chemicals in cigarette smoke can impair the mucociliary escalator, preventing natural cleansing of the respiratory tract.

- Chemicals in cigarette smoke can impair the mucociliary escalator, preventing natural cleansing of the respiratory tract. slide 9 - ciliary movement is impaired by: smoking, alcohol/narcotic abuse, viral infections. Increased the chance of infection if you can't move the mucus up and out of the lungs.

Which is the causative agent of the upper respiratory tract infection characterized by the formation of a pseudomembrane on the tonsils or in the throat? - Streptococcus pneumoniae - Mycobacterium tuberculosis - Corynebacterium diphtheriae - Mycoplasma pneumoniae - Bordetella pertussis

- Corynebacterium diphtheriae

A bacteriophage is necessary for toxin production in: - E. coli. - Staphylococcus aureus. - Corynebacterium diphtheriae. - Streptococcus pyogenes. - All of the answer choices are correct.

- Corynebacterium diphtheriae. - a lysogenic bateriophage - lysogenic converstion - it makes diphtheria toxin - an A-B exotoxin. Not a good question because the strains of S. pyogenes that make SPEs do so because of lysogenic converstion too. - superantigen - erythrogenic toxin -> scarlet fever.

Which of the following is/are not associated with strep throat? - Sore throat and fever. - Patches of pus in the throat. - Enlarged lymph nodes in the neck. - Cough and nasal discharge. - Abdominal pain and headache.

- Cough and nasal discharge. Strep throat is characterized by sore throat, difficulty swallowing, fever after an incubation period of 2-5 days. Throat red with patches of pus and scattered tiny hemorrhages. Lymph nodes in neck enlarged/tender. In older kids and young adults - abdominal pain or headache. Pts do not usually have a cough, weepy yes or runny nose. Spontaneously recover in 1 wk Many have mild or no symptoms at all.

Why are some tissues damaged by diphtheria toxin while others are unaffected by it? - Diphtheria toxin is a superantigen. Only TH cells are affected by this type of toxin, so tissues lacking TH cells are unaffected. - The causative agent is inhaled into the lungs, so only lung tissue is affected by the toxin released by the organism. - Diphtheria toxin is an A-B toxin. Cells that do not have a receptor for the toxin are unaffected by it. - The causative agent is ingested, so only gastrointestinal tissue is affected by the toxin released by the organism. - Diphtheria is a localized infection. Only tissues in the immediate area of the bacteria are affected by the toxin.

- Diphtheria toxin is an A-B toxin. Cells that do not have a receptor for the toxin are unaffected by it. Cells that do sustain heavy damage -> heart, kidney, nerves - why heart/kidney failure and paralysis can occur later.

Which is used in the vaccination for C. diphtheriae? - Protein A - M protein - Lipopolysaccharide - Intact bacteria - Exotoxin

- Exotoxin It is an inactivated toxoid vaccine - doesn't replicate in the host, is exotoxin treated with formalin - Toxoid vaccines use a toxin (harmful product) made by the germ that causes a disease. They create immunity to the parts of the germ that cause a disease instead of the germ itself. That means the immune response is targeted to the toxin instead of the whole germ. DTap - diphtheria, tetnus, pertussis - need a booster every 10 years as immunity decreases after childhood.

Your son comes home from school complaining that he is ill. He tells you he thinks he has the flu—he has a sore throat, runny nose, and a cough, and his eyes are very red. Everyone in your family received a influenza vaccine about a month ago, and as the CDC reports that this year's vaccine is approximately 70% effective, you think it is unlikely that your son does in fact have this disease. In addition, your son does not seem to have muscle aches or a headache, which generally occur with flu. Nonetheless, he does look ill and when you take his temperature, you find that he has a fever of 38.9oC. You take him to see his doctor, because you suspect that while your son likely does not have influenza, he also does not have a common cold. The doctor knows that your son is unlikely to have a common cold, based on which sign/symptom? A) Sore throat B) Fever C) Cough D) Runny nose E) Fatigue The doctor checks your son's throat and notes that he has has gray-white pus on the pharynx and tonsils. He also has enlarged lymph nodes in his neck. This suggests to the doctor that your son has the bacterial infection ________, which he attempts to confirm by ________. A) strep throat; doing a rapid antigen detection test (RADT) and throat culture. B) pneumococcal pneumonia; doing a rapid antigen detection test (RADT) and throat culture. C) mycoplasmal pneumonia; performing a mantoux skin test and doing a throat culture. D) legionellosis; performing a mantoux skin test and a chest x-ray. E) tuberculosis; doing a throat culture and rapid TB skin test.

- Fever (no fever with common cold) - strep throat; doing a rapid antigen detection test (RADT) and throat culture.

Which statement regarding common colds and adenoviral respiratory tract infections is TRUE? A) Fever is a sign of adenoviral respiratory tract infections, but is not a sign for the common cold. B) The incubation period for adenoviral respiratory tract infections is 1-2 days, while that for common colds is 5-10 days. C) Cold viruses are non-enveloped, double-stranded DNA viruses while adenoviruses are non-enveloped single-stranded RNA viruses. D) Cold viruses may cause infections other than respiratory infections while adenoviruses only cause upper respiratory tract infections. E) Adenoviral respiratory tract infections may also be caused by bacteria while the common cold is always caused by a virus of some kind.

- Fever is a sign of adenoviral respiratory tract infections, but is not a sign for the common cold.

- Freshwater streams AND cooling towers.

You are an RN working in the emergency department (ED) at a major hospital in New York City. During one shift, you see two patients who are exhibiting coughing with blood-containing sputum, and shortness of breath. Both patients report that they have experienced headaches, muscle aches, high fever, confusion, and shaking chills in the days preceding their ED visit. One of the patients also has some digestive tract symptoms including diarrhea, abdominal pain, and vomiting. You discover that the patients live in the same apartment building, although they do not know each other. You suspect that they have a type of pneumonia, and given the circumstances, think it may be legionellosis. You read up on this disease to refresh your memory about it. What is the likely source of the L. pneumophila in this case? A) The cooling water tower providing feeding air conditioners in the patient's offices. B) The showers or faucets at the local gym where both patients regularly worked out. C) The produce section at the grocery store where vegetables are sprayed with water for freshness. D) The water tank in the patient's building that provides hot water to apartments. E) Further investigation by an agency such as the CDC would be needed to determine this.

- Further investigation by an agency such as the CDC would be needed to determine this. - why this instead of the water at their apartment - I realized that if it was any of these sources then it wouldn't just be the two of them. There are a lot of places they could have been exposed and the CDC should investigate.

In tuberculosis, when a caseous lesion calcifies, it is called a _________. - tubercle - Ghon complex - tuberculous cavity - All of the choices are correct.

- Ghon complex

The most common bacterial pathogen(s) involved with sinusitis, otitis media, and conjunctivitis is/are: - S. aureus AND H. influenzae. - H. influenzae AND S. pneumoniae. - H. influenzae AND S. epidermidis. - S. pneumoniae AND S. aureus. - S. epidermidis AND S. pneumoniae.

- H. influenzae AND S. pneumoniae. Many people carry strains w/o effect. Haemophilus influenzae is a tiny, G- rod. Streptococcus pneumoniae is a G+ diplococcus with a capsule (virulence factor) and is just called pneumoccocus. Strains that infect the conjunctiva have ADHESINS to attach firmly to the conjunctiva.

The common cold - Epidemiology:

- Humans = only source of cold viruses - spread = virus-containing droplets we inhale or infected secretions we rub in w/ contaminated hands. - first 2-3 days - high [virus] in snot/on hands - most likely to transmit virus then - day 4/5 - virus levels undetectable - low levels can be present for 2 wks - infective dose - a few virions - colds NOT highly contagious with preventions like washing hands

Which of the following is associated with the upper respiratory system? - Humidifying inhaled air. - Warming inhaled air AND drying inhaled air. - Cooling inhaled air AND drying inhaled air. - Cooling inhaled air AND humidifying inhaled air. - Humidifying inhaled air AND warming inhaled air

- Humidifying inhaled air AND warming inhaled air Incoming cold air initiates a nervous response that brings more blood flow to warm incoming air and contact with the mucus membranes humidify incoming air.

Mycoplasmal Pneumonia = Walking Pneumonia

- Leading pneumonia of college students, common among military recruits, children and young adults; generally mild - does not show the severe signs/symptoms of most other pneumonias so is called Atypical Pneumonia Signs/Symptoms: - 2-3 wk incubation (all others were just a couple of days) - onset is gradual; initial symptoms are fever, headache, muscle pain, fatigue. Dry cough after several days; mucoid sputum may be produced later - otitis media in ~15% of cases Causative Agent: - Mycoplasma pneumonia - small bacterium with no cell walls that makes 'fried egg' colonies - grows slowly and is aerobic Pathogenesis: - only a few inhaled cells can start infection - cells use adhesion proteins to attach to respiratory epithelium - Interfere with ciliary action, cause cells to slough off - Inflammatory response with accumulation of lymphocytes and macrophages thickens walls of bronchial tubes and alveoli - damage to mucociliary escalator means more vulnerable to secondary bacterial infections Epidemiology: - s spread by aerosolized droplets shed from about 1 week before symptoms begin to many weeks afterward • Accounts for ~1/5 of bacterial pneumonias • Immunity following recovery not permanent; repeat attacks have occurred within 5 years Tx/Prevention: - Mycoplasma pneumoniae lacks cell walls so antibiotics like beta lactams aren't going to work. - • Tetracycline, erythromycin shorten illness if given early, but they are only bacteriostatic • No preventative measures exist except avoiding overcrowding in schools, military facilities

Which of the following bacterial pathogens is found in aquatic environments and is commonly present in air conditioning systems and cooling towers? - Klebsiella pneumoniae - Enterobacter aerogenes - Vibrio cholera - Legionella pneumophila

- Legionella pneumophila - found in natural waters, water system - L. pneumophila is protected from chlorine inside amoebas. (freshwater ones)

You are an RN working in the emergency department (ED) at a major hospital in New York City. During one shift, you see two patients who are exhibiting coughing with blood-containing sputum, and shortness of breath. Both patients report that they have experienced headaches, muscle aches, high fever, confusion, and shaking chills in the days preceding their ED visit. One of the patients also has some digestive tract symptoms including diarrhea, abdominal pain, and vomiting. You discover that the patients live in the same apartment building, although they do not know each other. You suspect that they have a type of pneumonia, and given the circumstances, think it may be legionellosis. You read up on this disease to refresh your memory about it. Select the FALSE statement regarding legionellosis and its causative agent. A) The causative organism survives well in the water systems of buildings, particularly in hot water systems, where chlorine levels are generally low. B) People become infected with L. pneumophila when they inhale aerosol droplets contaminated with the organism. It is not acquired from other infected individuals. C) L. pneumophila produces a β-lactamase, which makes it resistant to many penicillins and some cephalosporins, so is typically treated with a macrolide or a fluoroquinolone. D) Legionella pneumophila is an obligate intracellular parasite that survives in ameba in the environment and in kupffer cells in infected people. E) L. pneumophila prevents phagosome-lysosome fusion in phagocytes, thus avoiding destruction; the bacteria manipulate conditions to multiply within these cells.

- Legionella pneumophila is an obligate intracellular parasite that survives in ameba in the environment and in kupffer cells in infected people. Kupffer cells are macrophges in the liver. L. pneumophila lives in alveolar macrophages.

Which of the following proteins produced by B. anthracis function together to kill phagocytes? A) Local factor, protective antigen, AND edema factor. B) Lethal factor, protective antigen, AND edema factor. C) Local factor, protective antibody, AND edema factor. D) Lethal factor, protective antigen, AND endotoxin. E) Lethal factor, protective antibody, AND endotoxin.

- Lethal factor, protective antigen, AND edema factor.

Which of the following is a virulence factor of Streptococcus pyogenes? - M protein - Capsule - Endotoxin AND pili - M protein AND pili - M protein AND capsule

- M protein AND capsule M protein - adhesin. Inactivates C3b of compliment - INTERFERES WITH PHAGOCYTOSIS Capsule - hyaluronic acid - mimics host cell structure and INHIBITS PHAGOCYTOSIS

Mycobacterial infections in AIDS patients are mostly likely to be caused by ________. - Mycobacterium avium complex - Mycobacterium tuberculosis - Mycobacterium bovis - Mycobacterium africanum

- Mycobacterium avium complex

If you are a 20-year-old healthy young adult and you have to CHOOSE a type of pneumonia to become infected with (and you will NOT get treatment for it), which would be the 'best,' and why? - Pneumococcal pneumonia-it doesn't destroy lung tissue and can be completely recovered from. - Klebsiella pneumonia-it has the shortest recovery time. - Mycoplasmal pneumonia-it has the mildest symptoms and is generally easily cleared out. - Viral pneumonia-there are many antiviral medications you can take for this version with very few side effects.

- Mycoplasmal pneumonia-it has the mildest symptoms and is generally easily cleared out.

The best way to speed up recovery from a common cold is to: - dose the patient with ibuprofen to keep the fever down. - to take decongestants as a means of alleviating the symptoms of the cold. - to take 1,000 mg of vitamin C every day during the illness. - None of the above-in fact, the only way to clear out a cold is to let your immune system do its job. Several of the treatments above may actually INCREASE the time needed to get over the illness.

- None of the above-in fact, the only way to clear out a cold is to let your immune system do its job. Several of the treatments above may actually INCREASE the time needed to get over the illness. • No proven treatments • Viruses not affected by antibiotics, antibacterial medications **• Analgesics, antipyretics can reduce symptoms but may prolong symptoms and duration**

Select the best description of the causative agent of diphtheria. - Pleomorphic, Gram-negative lysogen. - Gram-positive, spore-forming rod. - Gram-positive, encapsulated, spore-former. - Pleomorphic, Gram-positive lysogen. - Pleomorphic, Gram-positive, flagellated lysogen.

- Pleomorphic, Gram-positive lysogen. Corynebacterium diphtheriae is a pleomorphic, non-motile, non-spore forming G+ rod that is a lysogen because it is a lysogenic bacteriophage that inserts its DNA into the bacteria's genome that causes it to make the diphtheria exotoxin (lysogenic conversion). - club-shaped and often arranged side-by-side in pallisades (like a wooden fence).

How are pleurisy and pneumonia are different? - Pleurisy is inflammation of the lungs (not necessarily due to a microbe), while pneumonia is microbial infection of the linings that surround the lungs. - Pneumonia is active microbial infection of the lungs, while pleurisy is inflammation of the linings that surround the lungs (not necessarily due to a microbe). - Pleurisy is caused by viruses (single-stranded or double-stranded RNA), while pneumonia is caused by bacteria (Gram-positive only). - Pneumonia is caused by viruses (single-stranded or double-stranded DNA), while pleurisy is caused by bacteria (Gram-negative or Gram-positive). - Pneumonia is always a fatal infection and cannot be easily treated while pleurisy is not—treatment of this condition is by antiviral medications.

- Pneumonia is active microbial infection of the lungs, while pleurisy is inflammation of the linings that surround the lungs (not necessarily due to a microbe). slide 13. Pneumonitis = inflammation of lungs, often viral. Pneumonitis that causes the alveoli to fill with pus/fluid = pneumonia.

Which of the following is specifically associated with diphtheria? - Pseudomembrane in throat - General malaise - Fever and sore throat - Microhemorrhages - Widespread rash

- Pseudomembrane in throat Signs and symptoms: 2-6 days after infection, mild sore throat, slight fever, extreme fatigue and malaise (general discomfort). Neck swells dramatically, pseudomembrane on tonsils/throat or in nasal cavity, heart/kidney failure and paralysis can happen later. - pseudomembrane - dead epithelial cells, clotted blood, fibrin and WBCs from inflammatory response to bacteria. Can become loose, obstruct airway - pt can suffocate.

Which step(s) of phagocytosis are avoided by Streptococcus pyogenes? - Recruitment of phagocytes AND phagolysosome formation - Phototaxis AND recognition and attachment - Recruitment of phagocytes AND recognition and attachment - Phagolysosome formation - Phagolysosome formation AND lysis

- Recruitment of phagocytes AND recognition and attachment Recruitment of phagocytes - makes C5a peptidase Recognition and attachment - capsules, M protein, Protein G = Fc receptors

Pneumococcal pneumona - causative agent:

- Steptococcus pneumoniae - a G+ diplococcus with a thick polysaccharide capsule (remember of sinusitis, otitis media and conjuntivitis slides) - virulence factor - cells are elongated with tapered end = lancet-shaped - strains with no capsule do not cause invasive disease

Which of the following statements regarding resistance in Klebsiella species is FALSE? A) β-lactamase confers resistance to β-lactam antibiotics such as penicillin. B) Extended-spectrum β-lactamase (ESBL) confers resistance to many of the cephalosporins. C) Carbapenemase confers resistance to carbapenems as well as other β-lactam drugs. D) There are few effective treatments available for carbapenem-resistant K. pneumoniae infections. E) Strains of Klebsiella that produce β-lactamase are resistant to penicillin but will respond to all cephalosporins.

- Strains of Klebsiella that produce β-lactamase are resistant to penicillin but will respond to all cephalosporins.

Which statement about S. pyogenes and strep throat pathogenesis is FALSE? - S. pyogenes strains that produce streptococcal pyrogenic exotoxins are lysogens. - Streptococcal pyrogenic exotoxins are A-B toxins that bind to host cells using the B portion. - Streptolysins O and S produced by S. pyogenes destroy blood cells by making holes in their cell membranes. - Spread of S. pyogenes is aided by streptokinase, an enzyme that breaks down blot clots. - The hyaluronic acid capsule of S. pyogenes helps it avoid the innate immune defenses.

- Streptococcal pyrogenic exotoxins are A-B toxins that bind to host cells using the B portion. SPEs are superantigens that causes a massive activation of T helper cells, cause them to release anti-inflammatory cytokines = Cytokine Storm -> seriousness of these infections.

Which of the following has been associated with the flesh-eating organism? - H. lechter - Pseudomonas aeruginosa - Streptococcus pyogenes - Staphylococcus aureus

- Streptococcus pyogenes - some Streptococcus pyrogenic exotoxin SPE-producing stains of Steptococcus pyogrenes cause toxic shock and necrotizing fasciitis.

The cause of strep throat is: - Staphylococcus aureus. - Streptococcus pyogenes—beta-hemolytic, group A. - Staphylococcus pyogenes—alpha-hemolytic, group B. - Streptococcus pneumoniae. - Staphylococcus aureus—beta-hemolytic, group A.

- Streptococcus pyogenes—beta-hemolytic, group A. Streptococcal pharyngitis (Strep Throat) G+ chains of beta-hemolytic GAS

Which of the following indicates bacterial conjunctivitis rather than viral conjunctivitis? - Increased tear production - Redness of conjunctiva - Swelling and pus - Sensitivity to light - All of the answer choices are correct.

- Swelling and pus Acute bacterial conjunctivitis - organisms probably inoculated directly onto conjuntiva from airborne respiratory droplets or from transfer from contaminated hands. - resist destruction by lysosyme - attachment aided by degradation of MUCIN, a protective component of surface membrane - attachment, then release tissue-damaging enzymes, sometimes combined with toxins, to harm eye tissue

Why would it be reasonable to treat strep throat but not diphtheria with antibacterial antibiotics? - The signs and symptoms of diphtheria are mostly caused by the exotoxin produced by the causative agent. An antibiotic won't affect the exotoxin. - The signs and symptoms of strep throat are mostly from the exotoxin produced by the causative agent. An antibiotic effectively eliminates these exotoxins. - The causative agent of diphtheria is a virus, not a bacterium. The drug would have no effect against this infectious agent. - There are no antibiotics that have proven effective against the bacterium that causes diphtheria. - The causative agent of diphtheria is pleomorphic and does not have a cell wall. There are thus no antibiotics that would be effective against this organism.

- The signs and symptoms of diphtheria are mostly caused by the exotoxin produced by the causative agent. An antibiotic won't affect the exotoxin. - strep throat - signs/symptoms due to virulence factors of S. pyogenes. - causative agent of diphtheria is Corynebacterium diphtheriae - a pleamorphic, non-motile, non-spore forming, G+ rod with irregularly staining metachormatic granules towards the ends. - both penicillin and erythromycin are effective against C. diphtheriae but can't do anything against absorbed toxin - penicillin is beta-lactam, erythromycin is macrolide - primarily bacteriostatic and works against protein synthesis

Why are there currently no vaccines against Streptococcus pyogenes? - There are many antigenic types in the M protein of this organism. A vaccine against one type might not protect against another. - There is great variation in the polysaccharide capsule of this organism. A vaccine against one type might not protect against another. - Antibodies to streptococcal M protein may also recognize and bind to myosin in the heart, causing autoimmunity and leading to rheumatic fever. - There is great variation in the M protein of this organism. A vaccine against one M type might not protect against another AND antibodies to streptococcal M protein may also recognize and bind to myosin in the heart, causing autoimmunity and leading to rheumatic fever. - There is great variation in the polysaccharide capsule of this organism. A vaccine against one type might not protect against another AND antibodies to streptococcal M protein may also recognize and bind to myosin in the heart, causing autoimmunity and leading to rheumatic fever.

- There is great variation in the M protein of this organism. A vaccine against one M type might not protect against another AND antibodies to streptococcal M protein may also recognize and bind to myosin in the heart, causing autoimmunity and leading to rheumatic fever. First part true - almost picked just that but the second part is true too and we don't want this post-streptococcal sequalae to occur. - an appropriate vaccine would have to protect against many different strains of S. pyogenes without causing an autoimmune resoonse (causing the immune system to act against "self")

How do adenoviruses avoid the adaptive immune system? A) They cloak themselves with a hyaluronic acid capsule. B) They interfere with antigen presentation on MHC class I molecules. C) They synthesize C5a peptidase. D) They block interferon and antiviral protein production. E) They interfere with antigen presentation on MHC class II molecules.

- They interfere with antigen presentation on MHC class I molecules.

Which of the following are considered diseases of the lower respiratory tract? A) Diphtheria and pneumonia B) Influenza and diphtheria C) Tuberculosis and pneumonia D) Common cold and tuberculosis E) Influenza and tuberculosis

- Tuberculosis and pneumonia TB is in lungs and so is pneumonia. Upper is head and neck, lower is chest.

Which of the following statements about otitis media is FALSE? - The causative organisms may form a biofilm, leading to chronic infections. - It is usually preceded by infections of the nasal cavity and upper pharynx. - It may sometimes spread to the membranes covering the brain, causing meningitis. - Using decongestants and antihistamines to treat otitis media is generally very effective. - Otitis media during the "flu" season can be decreased by giving the flu vaccine to infants in day-care facilities

- Using decongestants and antihistamines to treat otitis media is generally very effective.

What kind of media do we culture Corynebacterium diphtheriae on?

- a selective media with potassium tellerite - inhibits growth of normal throat microbiota and C. diphtheriae colonies will grow black or brown. - can also grow on Leoffler's medium - enhances the formation of metachromatic granules.

Pneumococcal Pneumonia Signs/Symptoms

- accounts for ~60% of adult pneumonia patients requiring hospitalization - pneumococci are an important cause of community-acquired pneumonia (CAP) - 1-3 days incubation. - preceded by 1-2 days of runny nose, upper respiratory congestion, then sudden fever and shaking chills. - cough, fever, chest pain, sputum production (pus, other material coughed up from lungs) - Sputum becomes pinkish or rust colored from blood, Severe chest pain aggravated by each breath or cough - Causes shallow rapid breathing - Patient develops dusky color from poor oxygenation - w/o tx survivors show profuse sweating and rapid return to normal temp after 7-10 days

The disease that closely resembles "strep throat" but is of viral origin is: A) adenoviral pharyngitis. B) otitis media. C) the common cold. D) tonsilitis. E) bronchitis.

- adenoviral pharyngitis. It's the gray-white pus seen on pharynx and tonsils.

M protein, a virulence factor of Streptococcus pyogenes, directly interferes with which of the following steps of phagocytosis? - elimination - adherence - digestion - chemotaxis

- adherence M protein - adhesin - lets cell attach to host cell. - it inactivates Cb3 - an opsonin - opsonins bind to antigen and make it more attractive to and easier for phagocytes to bind to and engulf. It says Evasion on the pic on slide 17...

Rapid diagnostic tests for streptococcal infections may use: - blood agar AND the Kirby-Bauer test. - antibodies AND blood agar. - DNA probes. - the Kirby-Bauer test AND DNA probes. - antibodies AND DNA probes.

- antibodies AND DNA probes. Antibodies is a given, blood agar isn't a rapid test - involves incubation, Kirby-Bauer isn't rapid either... Kirby-Bauer tests test whether particular bacteria are susceptible to specific antibiotics. -What is special about Mueller Hinton agar that makes it useful for the Kirby Bauer test? It is used for the routine susceptibility testing of non-fastidious microorganism by the Kirby-Bauer disk diffusion technique. Five percent sheep blood and nicotinamide adenine dinucleotide may also be added when susceptibility testing is done on Streptococcus species.

The virulence of Klebsiella is due partly to the: A) motility of the organism AND exotoxin produced. B) structure and organization of flagella. C) structure of their pili AND exotoxin produced. D) antiphagocytic properties of their capsules. E) exotoxin produced AND antiphagocytic properties of their capsules.

- antiphagocytic properties of their capsules. Can get into bloodstream and produce endotoxic shock though. K. pneumoniae is G- rod. G- have LPS in their outer membrane. LPS = endotoxin.

Diphtheria is treated with: - antitoxin and antibiotics. - anti-inflammatory drugs and antibiotics. - DPT vaccine. - diuretic drugs and antibiotics.

- antitoxin and antibiotics. Antibiotics to kill the bacteria and antitoxin to stop the toxin.

The RADT and throat culture are both negative for Streptococcus pyogenes, the causative agent of strep throat. The doctor tells you that your son likely has an adenoviral respiratory tract infection. Adenoviruses are resistant to destruction by detergents and alcohol solutions. This indicates that these viruses A) are double-stranded RNA viruses. B) are non-enveloped viruses. C) are enveloped viruses. D) are endospore-formers. E) are also resistant to multiple antibiotics.

- are non-enveloped viruses. Naked viruses are resistant to more things that will inactivate an enveloped one. Adenovirus - nakes, dsDNA and humans are their only reservoir.

Adenovirus

- attach to and infect epithelial cells, genome transported to host cell nucleus, virus multiplies - Mechanisms for avoiding host defenses: - delaying apoptosis - blocking interferon function - interfering with antigen presentation by MHC class I molecules MHC class 1 - can be made by any cell, intracellular antigens, present to CD8 Tc lymphocytes. - after replication complete, a virally encoded "death protein" is pruduced ->cell lysis - severe infection = extensive cell destruction/inflammation - different serotypes of adenoviruses affect different tissues.

The characteristic virulence factor of S. pneumoniae is: A) a capsule. B) flagella. C) pili. D) cilia. E) A-B toxin.

- capsule polysaccharide capsule that stops the opsonin C3b to avoid phagocytosis.

The pneumococcal vaccine is directed against the: A) flagella. B) pili. C) cilia. D) capsule. E) A-B toxin.

- capsule. The vaccines contain capsule polysaccharides from the 13 or 23 most common serotypes

Pneumococcal pneumonia - Tx/Prevention:

- early in illness? Penicillin, erythromycin (G+ diplococci with capsule, remember?) - strains resistant to antibiotics more common - PCV13 vaccine - Pneumococcal conjugate vaccine, 13 serotypes - for under 2, over 65 and people at high risk due to health conditions - contains capsular polysaccharides from 13 serotypes attached to bacterial proteins to create T-dependent antigens - polysaccharides are T-independent antigens and w/o the protein added wouldn't be enough alone to cause a large enough immune response in a child under 2. - PPSV23 vaccine - pneumococcal polysaccharide vaccine, 23 serotypes - dive at least 1 yr after getting the PCV13 - contains capsule polysaccharides from the 23 most common serotypes - recommended for all adults over 65 plus some high risk people.

Diphtheria toxin works on: - lysosomes. - mitochondria. - chloroplasts. - elongation factor 2. - messenger RNA.

- elongation factor 2. - the bacteria (C. diphteriae) grow in the throat but the toxin gets into the bloodstream (toxemia). An A-B toxin, the B subunit attached to host cell receptors -> endocytosis -> A subunit detaches and is activated to a functional enzyme that inactivated EF-2 that the host eukaryotic cell needs for its 80s ribosomes to move along mRNA - translation stops, cell dies. Enzyme is not used up, keeps inactivating EF-2 in that cell.

The conjuctivae: - have no resident bacteria. - are often covered with bacteria. - are populated with S. aureus. - are populated with S. pyogenes.

- have no resident bacteria. slide 11 - surface of the eye and lining of eyelids covered by conjuntiva. Conjuntiva - very few bacteria present, infection = conjuntivitis.

Projecting from the outer envelope of the influenza virus are two glycoproteins called: A) leukocidin and hemolysin. B) hyaluronidase and coagulase. C) hemagglutinin and neuraminidase. D) lysozyme and coagulase. E) coagulase and gp160.

- hemagglutinin and neuraminidase HA spikes attach to receptors on host epithelial cells. NA spikes are critical in the release of new virions - it destroys the host cell surface receptors that bind to budding virions. Subtypes of flu viruses based on HA, NA types - mostly HI,2,3 and Ni,2 infect people.

5. When in the human body, Legionella pneumophila resides: - in alveolar macrophages. - in alveoli. - in the lower intestinal tract. - in the meninges.

- in alveolar macrophages. - inhaled in aersolized water, they lodge in lungs and promote their uptake by alveolar macrophages. - surface protein called macrophage invasion potentiator (Mip) aids entry into macrophages - the cells also bind C3b as an opsonin

Rhinoviruses need to be grown: A) in living cells AND at 39°C. B) in synthetic media AND at 39°C. C) on blood agar AND at 33°C. D) in live animals or plants. E) in living cells AND at 33°C.

- in living cells AND at 33°C.

Pertussis "Whooping Cough"

- is preventable by vaccine - causes up to 1/2 million deaths every year and is endemic in the US Signs/Symptoms - 1-2 wks incubation stage - 3 stages - catarrhal, peroxysmal and convalescent stage - Catarrhal = inflammation of mucus membranes. lasts 1-2 wks, signs/symptoms resembling an upper respiratory tract infection (snot, sneeze, low fever, mild cough) - Paroxysmal = repeated sudden attacks, lasts 2-4 weeks or longer, frequent bursts of violent uncontrollable coughing. Dry cough, severe enough to burst small b.vessels in eyes. Tongue protrudes and neck veins stand out. Coughing spasm followed by 'whoops' as forceful attempts to inhale. Vomiting and seizures can occur/pt may become cyanotic ( blue from lack of oxygen) - Convalescent = recovery Not contagious, coughing decreases. Slow recovery over some weeks. Caustive Agent: - Bordatella pertussis = tiny G- rod, with capsule, aerobic. Cells sensitive to drying and sunlight, die quickly outside the host. Pathogenesis: - inhaled, attaches to ciliated cells of respiratory epithelium Attachment aided by 2 COLONIZATION FACTORS: - FHA - filamentous hemagglutinin - pilus from bacterial surface - fimbriae Colonizes upper throat, trachea, bronchi and bronchioles. grow in dense masses on epithelial surface but don't invade tissue. - release 3 TOXINS: - Pertussis toxin (PT) = A-B toxin - Adenylate cyclase toxin - Tracheal cytocoxin

Which of the following about Bacillus anthracis is TRUE? A) It contains lipopolysaccharide. B) It is flagellated. C) It is rod-shaped. D) It stains pink in the Gram stain. E) It causes hemolysis on blood agar.

- it is rod-shaped. Anthrax is a disease primarily of livestock but people get it too. Bacillus anthracis is G+, makes endospores, non-hemolytic, non-motile, rod shaped bacterium whose spores can remain in the environment indefinately and whose vegetative cells have a capsule made of an amino-acid polymer instead of polysaccharide.

Legionnaires' disease is so named because: - it caused a large epidemic among members of the French Foreign Legion. - it was first identified at a convention of the American Legion. - it was a common infection among foot soldiers. - None of the choices are correct.

- it was first identified at a convention of the American Legion. Legionnaires' Disease unknown until 1976 • Attendees of American Legion Convention in Philadelphia developed mysterious pneumonia

Bacterial infections of the lower respiratory system:

- less common than in the upper respiratory system but are much more serious. Pneumonia - disease of lower tract, alveoli fills with fluids like pus and blood. Typically results from an inflammatory response to micrboial infection of lungs and is the LEADING CAUSE OF DEATH due to infectious disease in the US.

Virulence factors used by S. pyogenes include all of the following EXCEPT: - protein F. - M protein. - a capsule. - lipopolysaccharide - protein G.

- lipopolysaccharide G+ chains, no outer membrane for LPS. protein F - attachment to fibrin, a protein on epithelial cells M protein - adhesin. Inactivates Cb3 of compliment Capsule - hyaluronic acid - mimics host cell structure. Protein G - binds to Fc of opsonizing IgG, avoids phagocytosis. - not listed are C5a peptidase, SPEs, streptolysins O and S plus tissue degrading enzymes (DNase, streptokinase (breaks down blood clots), hyaluronidase, proteases)

Adenovirus Respiratory Tract infections - Causative Agent

- more than 50 antigenic types of adenoviruses infect humans - naked, dsDNA - can remain infectious in the environment for long period of time, are resistant to destruction by detergents and alcohol solns BUT are easily inactivated by heat (56C), enough chlorine and various other disinfectants.

The preferred habitat of S. aureus is the: - throat. - urethra. - bladder. - nasal chamber.

- nasal chamber. slide 10 - 20% of healthy people carry Staphylococcus aureus - potential pathogen that is common in the nostrils

The eyes connect directly to the nasal passage through the: - frontal sinuses. - nasolacrimal ducts. - middle ear. - tonsils.

- nasolacrimal ducts. slide 11 - tear ducts connect to nasal chamber. Infection is dacryocystitis.

Otitis media and sinusitis are usually preceded by a(n): - middle ear infection. - pseudomonal infection. - oropharyngeal infection. - nasopharyngeal infection.

- nasopharyngeal infection. Middle ear opens up to the nasopharynx by eustachian tubes - infection damages the ciliated cells, resulting in inflammation and swelling.

Which of the following types of cell is able to create webs of extracellular fibers that help kill a variety of microbes? - platelets - NK cells - neutrophils - eosinophils

- neutrophils Ch 14.

The common cold - Tx/Prevention:

- no proven tx for common cold - analgesics (painkillers)/antipyretics (fever reducers) like aspirin/IBU can reduce symptoms but may prolong symptoms and duration of viral shedding and delay the antibody production that lead to recovery. - Prevention: handwashing, hands away from face, avoid crowded places, avoid people with colds for first few days, when they are shedding high numbers of viral particles. - NO VACCINE = large # of immunologically different viruses cause colds (more than 100 types!)

Adenoviruses - Epidemiology:

- only reservoir = humans - can persist in the environment - Naked, ssDNA - spread by respiratory droplets - crowded areas :( - asymptomatic infections common - virus shed from respiratory tract during acute illness and from feces for months afterwards

Influenza is caused by: A) orthomyxovirus. B) H. influenzae. C) cytomegalovirus. D) adenovirus. E) coronavirus.

- orthomyxovirus. Causative agent of Influenza A is virus in the orthomyxovirus family. Has an envelope, ssRNA in 8 segments.

Effective preventive methods for avoiding the common cold include all of the following EXCEPT: A) hand washing. B) avoiding crowds. C) not touching one's face. D) avoiding close contact with people with colds. E) prophylactic antibiotics.

- prophylactic antibiotics.

The common cold - Pathogenesis:

- rhinoviruses infect EPITHELIAL CELLS that line the upper respiratory tract - ciliary motions stops, cells die and slough off. - damage -> release of pro-inflammatory cytokines, stimulates nerve reflexes = increased snot, tissue swelling and sneezing (so congested, can't breathe!) - can spread to ears, sinuses or lower respiratory tract before the immune system stops the infection. - cause of pneumonia in immunocompromised.

The disease characterized by the appearance of a toxin-mediated rash that spares the area around the mouth and causes the tongue to look like the surface of a ripe strawberry is: - chickenpox. - scarlet fever. - strep throat. - measles.

- scarlet fever. Some strains of S. pyogenes make streptococcal pyrogenic exotoxins (SPE) that care called erythrotoxins - red toxins - red rash of scarlet fever. Signs and symptoms: high fever, rough skin, pink-red rash, strawberry tongue. - some SPE-producing stains cause toxic shock and necrotizing fasciitis.

The rhinovirus contains: A) single-stranded RNA and is an enveloped virus. B) double-stranded RNA and is an enveloped virus. C) single-stranded RNA and and is a non-enveloped virus. D) double-stranded RNA and is a non-enveloped virus. E) single-stranded RNA and and is a retrovirus.

- single-stranded RNA and and is a non-enveloped virus. p.543 "a group of NON-ENVELOPED virues with a SINGLE-STRANDED RNA genome" Other quizlet worksheet says A but...

The rhinovirus contains: - single-stranded RNA. - double-stranded RNA. - double-stranded DNA. - multiple pieces of single-stranded DNA.

- single-stranded RNA.

The signs and symptoms of adenovirus respiratory tract infections may be confused with those of: A) pneumonia AND tuberculosis. B) tuberculosis AND diphtheria. C) pertussis AND pneumonia. D) strep throat AND pneumonia. E) strep throat AND pertussis.

- strep throat AND pneumonia.

The key virulence factor of S. pneumoniae interferes with: A) the action of C3. B) the action of C3b. C) the action of C5a. D) interferon. E) All of the answer choices are correct.

- the action of C3b. 2 Virulence factors mess with the action of C3b - capsule = resistant to phagocytosis - interferes with the opsonin C3b - pneumococcal surface protein (PsaA) interferes with C3b too

A sharp reduction in the incidence of Haemophilus influenzae serotype b infections is principally due to: - the discovery of new antibiotics. - the development of an effective vaccine - the elimination of the natural reservoir of H. influenzae. - improvements in sanitary conditions in meat processing plants.

- the development of an effective vaccine

A sharp reduction in the incidence of Haemophilus influenzae serotype b infections is principally due to: A. the discovery of new antibiotics. B. the development of an effective vaccine. C. the elimination of the natural reservoir of H. influenzae. D. improvements in sanitary conditions in meat processing plants.

- the development of an effective vaccine.

The common cold - Signs/Symptoms:

- the most frequent infectious disease in humans, - accounts for >50% of upper respiratory tract infections each year. - 1-2 days after infection - malaise, then runny nose, sneezing, coughing, mildly sore throat and hoarseness. Snot is copious and water, may thicken and get cloudy. - NO FEVER unless secondary bacterial infection. - 1 wk, mild cough for a bit longer.

The eyes are protected from infection by: - the washing action of the tears and eyelids AND the use of contact lenses. - the washing action of the tears and eyelids AND the chemical action of lysozyme. - the chemical action of lysozyme AND the use of contact lenses. - the use of contact lenses AND the dryness of the eye surface. - the dryness of the eye surface AND the chemical action of lysozyme.

- the washing action of the tears and eyelids AND the chemical action of lysozyme.

A vaccine for the common cold is not possible because: A) the surface antigens of rhinovirus mutate frequently. B) there are more than 100 types of rhinovirus. C) the causative agent of colds is unknown. D) the rhinovirus cannot be grown in sufficient quantities. E) rhinoviruses are resistant.

- there are more than 100 types of rhinovirus.

You ask the doctor whether there is a vacccine that your children can be given to prevent further adenoviral infections. He tells you A) that there is no need for a vaccine because your son can be treated with antibiotics AND that adenovirus infections can be avoided by handwashing. B) there is a vaccine against two adenovirus serotypes but this is only given to military recruits AND that adenovirus infections can mostly be avoided by handwashing. C) there is a vaccine against two adenovirus serotypes but this is only given to healthcare personnel BUT that adenovirus infections are easily treated with antibiotics. D) it is not possible to generate vaccines against any double-stranded DNA viruses AND that adenovirus infections can be avoided by handwashing. E) it is not possible to synthesize vaccines for preventing diseases caused by RNA viruses BUT that adenovirus infections can be prevented with prophylactic antibiotics.

- there is a vaccine against two adenovirus serotypes but this is only given to military recruits AND that adenovirus infections can mostly be avoided by handwashing.

Which is used in the vaccination for C. diphtheriae? - protein A - M protein - toxoid - red blood cells

- toxoid Inactivated toxoid booster - diphtheriae, tetanus.

Which of the following are considered diseases of the lower respiratory tract? - diphtheria and pneumonia - influenza and diphtheria - tuberculosis and pneumonia - common cold and tuberculosis

- tuberculosis and pneumonia slide 5 - lower respiratory tract = chest. Often serious, may be fatal. Upper respiratory tract - head and neck, Colds & sinus infections - uncomfortable but not life-threatening - clear w/o tx in ~1 week.

Antigenic shifts may be the result of: A) two different viruses infecting a cell at the same time. B) the lysogenic conversion of two viruses. C) conjugation of two viruses. D) blending of a bacterial and a viral genome. E) the lysogenic conversion of two viruses AND blending of a bacterial and viral genome.

- two different viruses infecting a cell at the same time. How flu changes: - Antigenic DRIFT: minor mutations in HA and NA genes, often of a single amino acid; responsible for seasonal influenza - Immunity developed from previous year less effective - Antigenic SHIFT: uncommon; concurrent infection allows mixture of 8 RNA segments; causes pandemic influenza - Human strain can gain novel HA and/or NA antigens - Animal strain can gain ability to infect humans

Pneumococcal Pneumonia - Epidemiology:

- up to 30% of healthy people carry encapsulated pneumococci in throat - bacteria seldom reach lungs because mucociliary escalator removes them - impair the escalator, risk of this pneumonia rises dramatically. - alcohol, narcotic use, viral respiratory infections - increased risk in people over 50, heart or lung disease, diabetes cancer.

Otitis media probably develops from an infection that spread: - from the outer ear to the middle ear. - from the sensory neurons of the middle ear. - upward through the Eustachian tube. - through the tympanic membrane. - via the meninges.

- upward through the Eustachian tube.

- upward through the Eustachian tube. Middle ear connects to nasopharynx by the Eustachian tube - equalized the pressue and drain any fluid away.

Which is more likely to happen—antigenic DRIFT, or antigenic SHIFT—and why? A) Antigenic DRIFT, since infection with only a single virus strain is required, and the random mutations happen as the virus replicates in the infected person's cells. B) Antigenic SHIFT, since infection with only a single virus strain is required, and the random mutations happen as the virus replicates in the infected person's cells. C) Antigenic DRIFT, since infection with only a single virus strain is required and random mutations occur more readily in this situation than if two virus strains are present. D) Antigenic SHIFT, since multiple viruses in a cell at once means more RNA polymerase to copy the RNA, and therefore more possibilities for mistakes to be made (leading to mutations). E) Antigenic drift and antigenic shift occur at the same frequency. Genetic change is just as likely to occur if one viral strain or more than one strain is/are present.

A) Antigenic DRIFT, since infection with only a single virus strain is required, and the random mutations happen as the virus replicates in the infected person's cells.

You are an RN working in the emergency department (ED) at a major hospital in New York City. During one shift, you see two patients who are exhibiting coughing with blood-containing sputum, and shortness of breath. Both patients report that they have experienced headaches, muscle aches, high fever, confusion, and shaking chills in the days preceding their ED visit. One of the patients also has some digestive tract symptoms including diarrhea, abdominal pain, and vomiting. You discover that the patients live in the same apartment building, although they do not know each other. You suspect that they have a type of pneumonia, and given the circumstances, think it may be legionellosis. You read up on this disease to refresh your memory about it. L. pneumophila was unrecognized as the causative agent of legionellosis for a long time. Why is this? A) L. pneumophila both stains poorly with common methods, and is difficult to culture in the laboratory. B) The organism is fastidious and is difficult to culture in the laboratory. C) L. pneumophila stains poorly with common methods, so is difficult to detect. D) L. pneumophila has no surface antigens and thus cannot be stained with fluorescence. E) There is no way to grow L. pneumophila in vitro; this organism can only be cultivated in cell cultures or viruses.

A) L. pneumophila both stains poorly with common methods, and is difficult to culture in the laboratory.

Enlargement of which of the following structures may contribute to ear infections by interfering with normal drainage from Eustachian tubes? - Nasal chamber - Nasal conchae - Adenoids - Epiglottis - Parotid glands

Adenoids - tonsils at the back of the throat

Virulence factors used by S. pyogenes may be: - Protein F. - M Protein. - a capsule. - Protein G. - All of the choices are correct.

All of the choices are correct - Protein F attaches to surface protein on epithelial cells called fibrin. M protein is an adhesin and inactivates opsonin C3b and avoids activating complement inflammatory response. Capsule mimics host cell hyaluronic acid and hides cell from phagocytes, Protein G is an Fc receptor that binds Fc part of opsonizing IgG.

Newborn infants can be infected with Group _______ streptococcus during birth.

Which is more dangerous to human beings: antigenic DRIFT or antigenic SHIFT? A) Antigenic DRIFT, since this produces the quickest and largest degree of changes in the virus structure and we may not have immunity against it. B) Antigenic SHIFT, since this produces the quickest and largest degree of changes in the virus structure and we may not have immunity against it. C) Antigenic DRIFT; the small changes make the virus look like something we already have an immune response in place for, but we actually don't, letting the virus hide from the immune responses for a longer period of time. D) Antigenic SHIFT; the process completely changes the virus, allowing it to jump from one species to another (such as from birds into humans). As such, we have no responses in place for the new virus. E) These are equally dangerous. In both cases, major genetic and phenotypic changes occur in the virus, which means that people have absolutely no immune responses in place for dealing with the infection.

B) Antigenic SHIFT, since this produces the quickest and largest degree of changes in the virus structure and we may not have immunity against it.

Is antigenic shift alone likely to lead to influenza pandemics? A) Yes. ONLY antigenic shift can lead to the large-scale mixing of gene elements required to produce a pandemic flu strain. B) Perhaps, but it would most likely be a mixture of antigenic shift AND drift that would result in a pandemic strain. C) No. ONLY antigenic DRIFT can lead to the large-scale mixing of gene elements required to produce a pandemic flu strain. D) No. Antigenic SHIFT is responsible for changes in the hemagglutinin protein, while antigenic DRIFT is responsible for changes in the neuraminidase protein. You need both to lead to a pandemic strain. E) No. Antigenic SHIFT is responsible for changes in the neuraminidase protein, while antigenic DRIFT is responsible for changes in the hemagglutinin protein. You need both to lead to a pandemic strain.

B) Perhaps, but it would most likely be a mixture of antigenic shift AND drift that would result in a pandemic strain. The other options don't actually make sense at all, and the use of ONLY = no.

The reservoir of the common cold is the: A) family pet. B) human. C) infected fomite. D) fruit. E) rhinovirus.

B) human.

The causative agent of whooping cough is: A) parvovirus. B) M. pneumoniae. C) B. pertussis. D) S. aureus. E) W. pertussis.

B. pertussis. Bordatella pertussis - tiny G- rod with capsule, aerobic - sensitive to sunlight, drying, quickly dies outside host

Which of the following does NOT explain why a patient with Klebsiella pneumonia is more likely to die than one with pneumococcal pneumonia? A) Treatment options for Klebsiella pneumonia are limited because the causative agent is resistant to many antibiotics. Pneumococcal pneumonia can be treated with antibiotics such as penicillin. B) The causative agent of Klebsiella pneumonia is Gram-negative and may cause septic shock. Streptococcus pneumoniae is a Gram-positive bacterium so does not have endotoxin. C) The most severe types of Pneumococcal pneumonia can be prevented with the PPSV23 vaccine. There is no vaccine that protects against Klebsiella pneumonia. D) Klebsiella pneumoniae causes lung abscesses which may result in the death of the patient. Pneumococcal pneumonia does not result in permanent lung damage. E) All of these statements explain why Klebsiella pneumonia is more frequently fatal than pneumococcal pneumonia.

C) The most severe types of Pneumococcal pneumonia can be prevented with the PPSV23 vaccine. There is no vaccine that protects against Klebsiella pneumonia.

p. 537 Table 21.1 Virulence Factors of Streptococcus pyogenes C5a peptidase, Hyaluronic acid capsule, M protein, protein F, protein G, Streptococcal pyrogenic exotoxins (SPEs), Streptolysins O and S, Tissue-degrading enzymes

C5a peptidase - inhibits recruitment of phagocytes by destroying complement component C5a. Hyaluronic acid capsule - inhibits phagocytosis. M protein - interferes with phagocytosis by causing inactivation of complement component C3b, an opsonin; involved in attachment to host cells. protein F - responsible for attachment to host cells. protein G - binds to Fc portion of antibodies, thereby interfering with opsonization. Streptococcal pyrogenic exotoxins (SPEs) - superantigens responsible for scarlet fever, toxic shock, "flesh-eating" fasciitis Streptolysins O and S - Lyse leukocytes and erythrocytes Tissue-degrading enzymes - enhance spread of bacteria by breaking down DNA, proteins, blood clots, tissue and hyaluronic acid.

The resistance of the tubercle bacillus to various factors is probably due to its: A) cell wall. B) capsule. C) larger ribosomes. D) ability to adhere tightly.

Cell Wall Mycobacterium tuberculosis - slender, acid-fast, rod-shaped bacterium, aerobe with a generation time of over 16 hours. - cell wall contains mycolic acids, cells resist drying, disinfectants, strong acids and alkalis, responsible for acid-fast staining. - easily killed by PASTURIZATION

Why did it take so long to understand that L. pneumophila is the cause of a respiratory tract infection? A) It stains poorly and is difficult to detect. B) It has fastidious growth requirements and is difficult to culture. C) It is extremely rare in nature and is seldom present in a population. D) It has fastidious growth requirements and is difficult to culture AND it stains poorly and is difficult to detect. E) It is extremely small and can only be detected using electron microscopy AND it is extremely rare in nature and is seldom present in a population.

D) It has fastidious growth requirements and is difficult to culture AND it stains poorly and is difficult to detect. -rare in nature and seldom present in a population.

Why are pneumococcal pneumonia infections so dangerous in nursing homes? A) There is a vaccine for protecting children against pneumococcal pneumonia but no vaccine available for protection of older adults. B) There is no longer an antibiotic effective against the infection, and older adults are unable to fight the infection without medication. C) This type of pneumonia causes permanent lung damage, and old people often have impaired lung function in the first place. D) The immune system of older people is usually impaired, leaving them predisposed to more serious and potentially life-threatening pneumonia. E) This question is misleading. Pneumococcal infections are not dangerous.

D) The immune system of older people is usually impaired, leaving them predisposed to more serious and potentially life-threatening pneumonia.

The best way to speed up recovery from a common cold is: A) to dose the patient with ibuprofen to keep the fever down. Reducing fever speeds up recovery. B) to take decongestants as a means of alleviating the symptoms of the cold. C) to take 1,000 mg of vitamin C every day during the illness. Vitamin C destroys cold viruses. D) let the immune system do its job. Several of the treatments listed may actually increase the recovery time. E) take an antibiotic such as penicillin that will rid the body of the cold virus.

D) let the immune system do its job. Several of the treatments listed may actually increase the recovery time.

Beta-hemolytic group A streptococci are responsible for _________. A. rheumatic fever B. necrotizing fasciitis C. pharyngitis D. All of the choices are correct.

D. All of the choices are correct.

Mycoplasma pneumoniae: A. does not cause pneumonia despite its name. B. causes pneumonia more often than Streptococcus pneumoniae. C. causes pneumonia only in conjunction with viral activity. D. is one of the causes of atypical pneumonia.

D. is one of the causes of atypical pneumonia.

Which is true of hantavirus? A) It is a zoonosis involving mice. B) It has three segments of single-stranded RNA. C) The primary effect is to flood the lungs with fluid. D) Shock and death occur in 30% of the cases. E) All of the choices are correct.

E) All of the choices are correct. Caused by hantaviruses of bunyavirus family • Enveloped; ssRNA genome in three segments • Each type infects rodent species; harmless to them • Inflammatory response to viral antigen causes capillaries to leak plasma into lungs, suffocating patient, causing blood pressure to fall • Shock and death occur in more than 40% of cases (text = 30%)

Mycoplasmal and Klebsiella pneumonias: A) have similar incubation periods. B) have causative agents that lack cell walls. C) are serious diseases often requiring hospitalization. D) are both relatively mild diseases. E) None of the choices is correct.

E) None of the choices is correct.

Colds are effectively treated with: A) antibiotics. B) aspirin and acetaminophen. C) proteases. D) nucleotide analogs. E) None of the choices is correct.

E) None of the choices is correct. - Viruses don't respond to antibiotics. - aspirin and APAP are about making symptoms less so the person is more comfortable No vaccines for the common cold so none of the choices are correct.

The illness in strep throat is largely from the exotoxin produced. An antibiotic effectively eliminates exotoxins T/F

False

There are no antibiotics that have proven effective against the bacterium that causes diphtheria. T/F

False

Diphtheria is a contagious disease that spreads from person to person mainly by the fecal-oral route. T/F

False - Spread by AIR, acquired via inhalation or from fomites. Cutaneous diphtheria with chronic ulcers - may be a source is a person comes into contact with them.

Corynebacterium diphtheriae is an invasive, toxin-producing, pleomorphic spore-forming bacterium that aggressively enters tissues and the bloodstream. T/F

False Bacterium stays in the throat - is non-motile = Non-invasive non-spore forming It's the A-B exotoxin it produces (lysogenic conversion) that enters the blood stream and moves throughout the body (toxemia).

Once the initial case has occurred, Legionnaires' disease spreads as a propagated epidemic. T/F

False Common Source, I'd think.

The causative agent of diphtheria is a virus, not a bacterium. The antibiotic would have no effect. T/F

False Corynebacterium diphtheriae is a pleomorphic, non-motile, non-spore forming G+ rod that is a lysogen.

Mycoplasma is effectively treated with cell wall inhibiting antibiotics. T/F

False No cell wall so...

Streptococcus pneumoniae is the most prevalent Gram-negative bacterium isolated from pneumonia patients. T/F

False Streptococcus pneumoniae is a gram-POSITIVE diplococci with a capsule

People infected with M. tuberculosis are always highly infectious to everyone around them-true or false, and why? - True-they are constantly shedding bacteria to the environment around them in high numbers, facilitating transmission. - False-while in the early stages of the illness, their tissues are not irritated and damaged to induce the cough required to spread the organism in respiratory droplets very easily. - True-as the mode of transmission is direct contact, anyone or anything they touch can be infected. - False-since TB requires a very high infectious dose, in the early stages of the disease, the patients aren't producing enough bacteria in their respiratory secretions to be infectious.

False-while in the early stages of the illness, their tissues are not irritated and damaged to induce the cough required to spread the organism in respiratory droplets very easily. - infection by Mycobacterium tuberculosis results in asymptomatic lung infection - Mycobacterium tuberculosis • Slender, acid-fast, rod-shaped bacterium • Strict aerobe with generation time over 16 hours • Unusual cell wall contains mycolic acids: cells resist drying, disinfectants, strong acids and alkali; responsible for acid-fast staining • Easily killed by pasteurization

Which of the following interferes with phagocytosis of S. pyogenes? - Hyaluronic acid capsule - M protein - C5a peptidase - Protein G - All of the answer choices are correct.

Hyaluronic acid capsule - I think it should be ALL. Table 21.1 literally says, "INHIBITS PHAGOCYTOSIS" Capsule mimics host cell component - phagocytes don't see it. M protein in S. pyogenes is an important adhesin that functions in attachment to the host cell - the antibodies that attach to M protein prevent infection. M protein also interferes with phagocytosis by inactivating the opsonin C3b from compliment, prevents complement activation too. C5a peptidase inactivated the chemoattractant C5a - avoids calling phagocytes to the area. Protein G is an Fc receptor that binds Fc part of opsonizing IgG - so phagocytes don't want to eat it.

In which disease are monoclonal antibodies against PA protein used as treatment? A) Inhalation anthrax B) Legionellosis C) Pertussis D) Pneumococcal pneumonia E) Influenza

Inhalation anthrax Anthrax is a disease primarily of livestock but people get it too. Bacillus anthracis is G+, makes endospores, non-hemolytic, non-motile, rod shaped bacterium whose spores can remain in the environment indefinately and whose vegetative cells have a capsule made of an amino-acid polymer instead of polysaccharide.

Why is Legionella pneumophila detected using immunofluorescence? A) It is a virus. B) It stains poorly with conventional dyes. C) It is Gram-non-reactive. D) It is an acid-fast bacterium. E) It lacks a peptidoglycan cell wall.

It stains poorly with conventional dyes. - Legionella pneumophila G- rod, fastidious (needs added nutrients if we want to culture it) Stains poorly in tissue/with conventional dyes Facultative intracellular parasite - live in freshwater amoebas and can persist in biofilms (if disturbed, huge numbers can be released) p.556 "the organism stains poorly with conventianal dyes, but it can be detected using immunofluorescence."

How does Legionella pneumophila survive adverse conditions? A) It forms endospores when in dry or hot environments. B) It produces cysts. C) It is acid-fast and resists dehydration. D) It survives in protozoa that can withstand adverse conditions. E) It is an intracellular parasite in fish.

It survives in protozoa that can withstand adverse conditions. Facultative intracellular parasite; survives well in freshwater amebas, which can form cysts during adverse conditions, allowing bacteria within to survive - inhaled in aersolized water, they lodge in lungs and promote their uptake by alveolar macrophages. - surface protein called macrophage invasion potentiator (Mip) aids entry into macrophages - the cells also bind C3b as an opsonin

Which is FALSE about pertussis toxin? A) It uses part B to attach to receptors on the host cell. B) It uses part A to inactivate G protein. C) It affects the level of cAMP in a cell. D) It affects the level of mucus secretion. E) It uses part A to attach to receptors on the host cell.

It uses part A to attach to receptors on the host cell. Pertussis toxin is an A-B toxin - part B does attach to receptors on the host cell - part A does inactivate G protein (regulatory protein in host cell) - it does affect the level of cAMP in cell which affects the level of mucus secretion

The process used for identifying different carbohydrates of streptococci: - Lancefield grouping. - CHO typing. - peptidoglycan typing. - fermentation testing. - NAAT typing.

Lancefield Grouping - Better predictor of pathogenic potential then hemolysis (beta or alpha on blood agar plate)

Legionella pneumophila, a fastidious Gram-negative rod.

The bacterial lung infection acquired by inhalation of aerosols of contaminated water is:

Legionnaires' Disease

In S. pyogenes, which of the following interferes with phagocytosis? - M protein - protein A - collagen - pilin

M protein Table 21.1 literally says, "interferes with phagocytosis" M protein in S. pyogenes is an important adhesin that functions in attachment to the host cell - the antibodies that attach to M protein prevent infection. M protein also interferes with phagocytosis by inactivating the opsonin C3b from compliment, prevents complement activation too. More than 80 antigenic types of M protein exist! - Different S. pyogenes strains with in GAS are distinguished by variations in the virulence factor M protein on their surface.

Adenoviral pharyngitis is effectively treated with: A) antibiotics. B) lysozyme. C) proteases. D) nucleotide analogs. E) None of the choices is correct.

None of the choices is correct.

Which of the following most accurately describes the pathogenesis of inhalation anthrax? A) EF binds to host cell membranes, forming a pore that allows PA or LF to enter the cells, where they disrupt critical cell functions. This triggers a series of events that cause death of the cell resulting in pulmonary edema. B) PA binds to host cell membranes, forming a pore that allows EF or LF to enter the cells, where they disrupt critical cell functions. This triggers a series of events that cause death of the cell resulting in pulmonary edema. C) LF binds to host cell membranes, forming a pore that allows EF or PA to enter the cells, where they disrupt critical cell functions. This triggers a series of events that cause death of the cell resulting in pulmonary edema. D) PA and EF bind to host cell membranes, forming a pore that allows LF to enter the cells, where they disrupt critical cell functions. This triggers a series of events that cause death of the cell resulting in pulmonary edema. E) EF and LF bind to host cell membranes, forming a pore that allows PA to enter the cells, where it disrupts critical cell functions. This triggers a series of events that cause death of the cell resulting in pulmonary edema.

PA binds to host cell membranes, forming a pore that allows EF or LF to enter the cells, where they disrupt critical cell functions. This triggers a series of events that cause death of the cell resulting in pulmonary edema. See, the endospores sit in the lungs for up to 60 days before they head to the chest lymph nodes to germinate but the vegetative cells make 3 proteins that function together as anthrax toxin to kill phagocytes and damage surrounding tissues. p.558 "First, PA (protective antigen) binds to host cells, forming a pore that allows EF (edema factor) or LF (lethal factor) to enter the cells, where they disrupt critical cell functions. This results in pulmonary edema, and triggers a series of events that cause death of the cell."

The 3 toxins that Bordatella pertussis produces:

Petussis Toxin (PT) - an A-B toxin, B attaches to receptor on host cell, A detaches and gets into cytoplasm where it is activated into an ENZYME. It activates a membrane-bound regulatory protein that controls production of cAMP, leading to more cAMP being made. High levels of cAMP interfere with cell isgnalling -> significant increase in mucus made, decreased killing ability of phagocytes, massive release of lymphocytes into blood, ineffective NK cells and low blood sugar. Adenylate cyclase toxin (ACT) - an a membrane-damaging toxin and an enzyme. Toxin reduces phygocytosis by causing lysis of accumulating WBCs. INsdie the cell it also catalyzes the rxn that converts ATP to cAMP. Tracheal cytotoxin (TCT) - is a fragment of peptidoglycan that B. pertussis released during growth and it causes host cells to release a fever-inducing cytokine (interleukin-1). Is also toxic to ciliated epithelial cells - they die and slough off, rapid decline in ciliary action.

The scientist who developed a system of identifying the variety of strains of Streptococci was: - Hans Zimmer. - Donald Sutherland. - O. T. Avery. - Rebecca Lancefield. - Louis Pasteur.

Rebecca Lancefield

Rebecca Lancefield - demonstrated that streptococci can be classified according to their cell wall carbohydrates. - this system : Lancefield grouping Before Lancefield streptococcal classification was based on the type of hemolysis displayed when organism were grown on blood agar. - beta hemolysis = clear spots on blood agar - alpha hemolysis = greenish partial clearing on blood agar

Rebecca Lancefield • divided streptococci into groups based on surface antigens instead of blood agar hemolysis • α-hemolytic streptococci • classified β-hemolytic streptococci according to cell wall carbohydrates • System now known as "Lancefield grouping" • Strains from human infections have same cell wall carbohydrate ("A"), different from other sources • Better predictor of pathogenic potential then hemolysis •

About 60% of the bacterial pneumonias that require hospitalization of adults are caused by: A) S. pyogenes. B) S. pneumoniae. C) S. aureus. D) K. pneumoniae. E) M. pneumoniae.

S. pneumoniae - G+ diplococci, with capsule

You are an RN working in the emergency department (ED) at a major hospital in New York City. During one shift, you see two patients who are exhibiting coughing with blood-containing sputum, and shortness of breath. Both patients report that they have experienced headaches, muscle aches, high fever, confusion, and shaking chills in the days preceding their ED visit. One of the patients also has some digestive tract symptoms including diarrhea, abdominal pain, and vomiting. You discover that the patients live in the same apartment building, although they do not know each other. You suspect that they have a type of pneumonia, and given the circumstances, think it may be legionellosis. You read up on this disease to refresh your memory about it. L. pneumophila is a facultative intracellular parasite. How does it manipulate the immune system so as to enter host cells? A) The bacterial cells bind complement component C3b (an opsonin), enhancing phagocytosis. B) The bacteria have macrophage invasion potentiator (Mip) that promotes their uptake by alveolar macrophages. C) The bacteria cause necrosis of alveolar cells, leading to an inflammatory response. D) The bacteria survive in alveolar macrophages by preventing phagosome-lysosome fusion AND the bacteria cause necrosis of alveolar cells, leading to an inflammatory response. E) The bacterial cells bind complement component C3b (an opsonin), enhancing phagocytosis AND the bacteria have a surface protein (Mip) that promotes their uptake by alveolar macrophages.

The bacterial cells bind complement component C3b (an opsonin), enhancing phagocytosis AND the bacteria have a surface protein (Mip) that promotes their uptake by alveolar macrophages.

Why is legionellosis not treated with β-lactam medications? A) The causative organism produces β-lactamases, so is resistant to many of these medications. B) The medication must be able to accumulate within alveolar macrophages to be effective, which β-lactam antibiotics do poorly. C) The causative organism produces β-lactamases, so is resistant to many of these medications AND the causative organism is acid-fast, so has mycolic acids and waxes in the cell wall that β-lactams cannot penetrate. D) The causative organism is acid-fast, so has mycolic acids and waxes in the cell wall that β-lactams cannot penetrate AND the causative organism produces endospores so is highly resistant to these medications. E) The medication must be able to accumulate within alveolar macrophages to be effective, which β-lactam antibiotics do poorly AND the causative organism produces β-lactamases, so is resistant to many of these medications.

The medication must be able to accumulate within alveolar macrophages to be effective, which β-lactam antibiotics do poorly AND the causative organism produces β-lactamases, so is resistant to many of these medications. Legionella pneumophila produces a beta lactamase, makes it resistant to many penicillins and some cephalosproins. Because the bacteria multiply inside the alveolar macrophages, medication must be able to accumulate within these cells to be effective, which beta lactam antibiotics do poorly. p.557

Why is it so important to protect against influenza?

The vaccine is fairly effective in protecting against the flu. However, a problem comes from the changing nature of the flu virus. The antibody generated from the last exposure may be useless against the next iteration of the virus. The virus has several segments of RNA and is also found in animals. Both of these characteristics allow for changing and mixing of the nucleic acid, which may be reflected in changes in the antigenic nature of the virus. Therefore, every year there is a possibility that the antigens have changed enough from the last infection to be unrecognizable. In particular, the changes appear in the neuraminidase and hemagglutinin molecules coating the virus.

Which is/are true of coccidioidomycosis and histoplasmosis? - They are both soil fungi.They are both dimorphic fungi. - They are both life-threatening. - They may be treated with antibiotics. - They are both soil fungi AND they are both dimorphic fungi.

They are both soil fungi AND they are both dimorphic fungi.

A variety of free-living amoebae and ciliated protozoa are thought to provide a natural reservoir for survival and growth of Legionella spp. in nature. T/F

True

Adenoviruses may cause eye infections as well as upper respiratory tract infections. T/F

True

Diphtheria exotoxin is made only by strains of Corynebacterium diphtheriae that carry a prophage containing the tox gene.T/F

True

Histoplasmosis may mimic tuberculosis. T/F

True

Klebsiella species easily acquire and are a source of R pneumococcal pneumonia. T/F

True

New cases of tuberculosis are frequently the result of reactivation of old dormant infections. T/F

True

Of infectious diseases, pneumonia is a major killer in the general population. T/F

True

T/F - Pneumonias are inflammatory diseases of the lung in which fluid fills the alveoli.

True

T/F - Streptococci are grouped by their cell wall carbohydrates.

True

T/F - Otitis media is an infection of the middle ear that is rare in the first month of life.

True - it becomes very common in early childhood, children who use pacifiers after age 2 have an increased risk of developing otitis media. Older children develop immunity to H. influenzae and the bacterium rarely causes otitis media in children older then 5. Sinusitis affects adults and older children.

Klebsiella easily acquire and are a source of R factors. T/F

True Resistance transfer factor (shortened as R-factor or RTF) is an old name for a plasmid that codes for antibiotic resistance.

Pneumococcal pneumonia - Pathogenesis: - encapsulated pneumococci inhaled into alveoli multiply rapidly, cause inflammatory response - Can affect nerve endings, cause pain: pleurisy

Virulence factors - capsule = resistant to phagocytosis - interferes with the opsonin C3b - pneumococcal surface protein (PsaA) interferes with C3b too - pneumolysin - membrane-damaging toxin that destroys ciliated epithelium - caused inflammatory response -> accumulation of fluid and phagocytic cells in alveoli -> difficult breathing. Can see the fluid as abnormal shadows on X-rays. Sputum has increasing amounts of pus, blood and bacteria If pneumococci enter blood from inflamed lungs = 3 outcomes - potentially fatal - sepsis = bloodstream infection - endocarditis = infection of heart valves - meningitis = infection of the meninges W/o complications in a wk you'll make enough anti-capsular antibodies to allow phagocytosis and destruction of the pneumococci = complete recovery

The destructive nature of tuberculosis can be characterized as a(n): A) endotoxin pyrogenic response. B) delayed-type cell-mediated hypersensitivity reaction. C) immune complex reaction. D) inflammatory response. E) inflammatory pyogenic response.

delayed-type cell-mediated hypersensitivity reaction. Type IV hypersensitivies are mediated by T cells - I suspect this is a poorly worded question. p.554 " this reaction is due to the accumulation of macrophages and T lymphocytes at the injection site, caused by a delayed type hypersensitivity reaction to the injected antigens." It is talking about the tuberculin skin test (TST)/Mantoux test

Rebecca Lancefield showed that almost all the strains of b-hemolytic streptococci from human infections: - could cause rheumatic fever. - had the same cell wall carbohydrate "A." - had variable cell wall carbohydrates. - responded to penicillin. - had the same cell wall carbohydrate "beta."

had the same cell wall carbohydrate (surface antigen), carbohydrate "A" - B also available, C = carbohydrate antigen on cells of horses, cattle and guinea pigs, D on cell wall of human normal microbiota

Primary reservoir for Diphtheria is:

humans - Spread by AIR, acquired via inhalation or from fomites. Cutaneous diphtheria with chronic ulcers - may be a source is a person comes into contact with them. - treat with injection of anti-serum - give immediately is diphtheria is suspected because the delay to culture it could be fatal. - antibodies can clear the bacterium but too much absorbed toxin can be deadly. - even with treatment, mortality is ~10%

The spread of mycoplasma is through: A) inhalation of infected droplets. B) the fecal-oral route. C) an insect vector. D) a fomite such as a towel. E) opportunistic normal microbiota.

inhalation of infected droplets.

The sudden, violent, uncontrollable cough of pertussis is described as: A) productive. B) contagious. C) infective. D) paroxysmal. E) catastrophic.

paroxysmal. Occurs during paroxysmal stage - 3 stages for pertussis Catarrhal stage - inflammation of mucus membranes Paroxysmal stage - repeated sudden attacks - the cough and the whoop Convalescent stage - not contagious, recovery

Although unusually resistant to many control factors, the tubercle bacillus is easily killed by: A) strong acids. B) disinfectants. C) pasteurization. D) strong alkalis. E) All of the answer choices are correct.

pasteurization. Mycobacterium tuberculosis - slender, acid-fast, rod-shaped bacterium, aerobe with a generation time of over 16 hours. - cell wall contains mycolic acids, cells resist drying, disinfectants, strong acids and alkalis, responsible for acid-fast staining. - easily killed by PASTURIZATION

Most colds are probably caused by: A) rhinovirus. B) S. aureus. C) Pseudomonas sp. D) E. coli. E) varicella.

rhinovirus. More than 100 types of human rhinoviruses.

The virulence of the tubercle bacillus is due to its: A) toxin. B) lysogenic conversion. C) resistance to antibiotics. D) survival within macrophages. E) lysogenic conversion AND resistance to antibiotics.

survival within macrophages. Look at your PP notes - I laid it all out nice and neat in the notes. - airborne cells inhaled into lungs - Alveolar macrophages engulf; unable to destroy - Mycolic acids prevent fusion of phagosome with lysosomes - Bacteria exit, multiply within macrophage's cytoplasm

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