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94 Cards in this Set
- Front
- Back
What in gram positive bacteria induces TNF and IL-1?
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Teichoic acid
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What in gram negative bacteria induces TNF and IL-1?
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Lipid A from LPS (outer membrane)
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Which bacteria has no cell wall?
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Mycoplasma
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What do you use to culture H. influenzae?
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Chocolate agar with factors V (NAD+) and X (hematin)
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What do you use to culture M. tuberculosis?
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Lowenstein-Jensen agar
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What do you use to culture fungi?
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Sabouraud's agar
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What bacteria are intracellular?
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Rickettsia, Chlamydia, and Legionella
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Which bacteria are encapsulated?
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Klebsiella, Salmonella, Streptococcus Pneumoniae, Haemophilus influenzae, and Neisseria meningitidis.
Diagonised with a positive quelling reaction |
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What is the only gram positive bacteria with endotoxin?
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Listeria monocytogenes
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What test is used to detect a recent S. pyogenes infection?
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ASO titer
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Glycocalyx
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For bacteria, this mediates adherence to surfaces, especially foreign surfaces (indwelling catheters).
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Teichoic acid
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Unique to cell wall of gram positive organisms. Induces TNF and IL-1.
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Outer membrane
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Lippopolysaccharide. Unique to cell wall of gram negative organisms. Lipid A induces TNF and IL-1.
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What bacteria have unusual cell membranes/walls and what is unusual?
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Mycoplasma - contains sterols and has no cell wall
Mycobacteria - contains mycolic acid and has a high lipid content |
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Which bacteria do not gram stain well?
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Treponema, Rickettsia, Mycobacteria, Mycoplasma, Legionella pneumophila, and Chlamydia.
These Rascals May Microscopically Lack Color. |
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What stain is used for Cryptococcus neoformans?
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India ink
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What stain is used for Legionella?
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Silver stain; also used for fungi
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What culture media is used for H. influenzae?
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Chocolate agar with factors V (NAD+) and X (hematin).
Some CHOCOLATE from the five (V) and dime (X) will make that FLU feel better. |
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What culture media is used for M. tuberculosis?
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Lowenstein-Jensen agar
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What culture media is used for fungi?
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Sabouraud's agar
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What is MacConkey's agar?
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Used for lactose fermenting enterics; fermentation produces acid, turning plate pink); bile salts and crystal violet inhibit gram + growth.
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What bacteria are obligate aerobes?
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Nocardia, Pseudomonas, Mycobacterium tuberculosis, and Bacillus
Nagging Pests Must Breath. |
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What bacteria are obligate anaerobes?
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Clostridium, Bacteroides (found in gut), and Actinomyces = Anaerobes Can't Breath Air.
They lack catalase and/or superoxide dismutase and are thus susceptible to oxidative damage. Aminoglycosides are ineffective b/c these antibiotics require O2 to enter the bacterial cell. Drugs of choice - clindamycin and metronidazole |
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What bacteria are obligate intracellular?
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Rickettsia, Chlamydia - can't make either own ATP
also Legionella Stay inside because it's Really Cold (and Legionella). |
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Which bacteria are encapsulated?
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Klebsiella pneumoniae, Salmonella, Streptococcus pneumoniae, Haemophilus influenzae type B, and Neisseria meningitidis.
Kapsules Shield SHiN SHiN can produce IgA protease, cause meningitis, and take up DNA from the environment. |
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Staph aureus alpha-toxin
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Causes hemolysis
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Staph aureus beta-toxin
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Sphingomyelinase
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Staph aureus proteins A, B, and C of gamma toxin
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A+B = hemolysin
B+C = leukocidin |
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Staph aureus TSST-1
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Causes toxic shock syndrome; release of cytokines
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Staph aureus exfoliative toxin
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Causes scalded skin syndrome
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What toxins are secreted by Streptococcus pyogenes (group A step)? What is the action of each?
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Streptolysin O - hemolysis; oxygen labile
Steptolysin S - hemolysis; oxygen Stable Erythrogenic/pyrogenic toxins - skin rash and fever of scarlet fever |
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What do ASO titers detect?
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Group A streptococcus (AntiStreptolysin O); used to detect rheumatic fever.
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Superantigens
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Bind directly to MHC II and T-cell receptors simultaneously, activating large numbers of T cells to stimulate release of INF-gamma and IL-2.
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ADP ribosylating A-B toxins
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ADP ribosylating A-B toxin
Interferes with host cell function. B (binding) component binds to a receptor on surface of host cell, enabling endocytosis. A (active) component then attaches an ADP-ribosyl to a host protein (ADP ribosylation), altering protein function. |
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Corynebacterium diphtheriae toxin
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ADP ribosylating A-B toxin
Inactivates elongation factor (EF-2); causes pharyngitis and "pseudomembrane" in throat. Do not scrape pseudomembrane; this will cause the toxin to go systemic and affect protein synthesis in the heart and brain. |
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Vibrio cholerae toxin
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ADP ribosylating A-B toxin
ADP ribosylation of G protein stimulates adenylyl cyclase, increasing Cl pumping into the gut and decreasing Na absorption. H2O moves into gut lumen; causes voluminous rice-water diarrhea. |
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E. coli toxin
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ADP ribosylating A-B toxin
ETEC; Heat-labile toxin stimulates adenylate cyclase; heat-stable toxin stimulates guanylate cyclase. Both cause watery diarrhea. Labile like the Air, Stable like the Ground. |
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Bordetella pertussis toxin
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ADP ribosylating A-B toxin
Increases cAMP by inhibiting Galpha1 (Gi); causes whooping cough; inhibits chemokine receptor, causing lymphocytosis. |
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Clostridium perfringens toxin
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Alpha toxin causes gas gangrene; get double zone of hemolysis on blood agar.
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C. tetani toxin
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Blocks the release of GABA and glycine; causes "lockjaw".
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Bacillus anthracis toxin
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Edema factor, part of the toxin complex, is an adenylate cyclase.
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Shigella toxin
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Shiga toxin (also part of E. coli O157:H7) cleaves host cell rRNA (inactivates 60S ribosome); also enhances cytokine release, causing hemolytic uremic syndrome.
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Mutated CMV DNA polymerase or lack of viral protein kinase
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Ganciclovir Resistance
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What organisms are most commonly implicated in subacute endocarditis?
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Streptococcus viridans, staphylococcus epidermidis, enterococci
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What is the most common aerobic skin flora?
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Staphylococcus epidermidis
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What 4 conditions is Streptococcus pneumoniae the most common cause of?
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Meningitis, Otitis media, Pneumonia, Sinusitis
S. pneumo MOPS are Most OPtochin Sensitive Associated with "rusty" sputum, sepsis in sickle cell anemia and splenectomy. |
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What bacteria are most responsible for neonatal death?
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Group B strep, E. coli, and Listeria
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What is the pathogenesis behind rheumatic fever?
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Antibodies against M protein enhance host defenses against S. pyogenes but can give rise to rheumatic fever.
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What bacteria form spores?
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Only certain gram positive rods form spores - Bacillus anthracis, Clostridium perfringens, Clostridium tetani, Bacillus cereus, C. botulinum, and Coxiella burnetti.
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What antibiotic use is most likely to result in C. diff superinfection? What is the treatment?
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Clindamycin or ampicillin
Treatment is metronidazole or oral vancomycin. |
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What is a toxicity of methicillin?
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Hypersensitivity and interstitial nephritis
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Coinfection of N. gonnorhea and C. trachomatis is common. What antibiotics should be given to cover both?
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N. gonnorhea - ceftriaxone or fluoroquinolone
C. trichomatis - azithromycin or doxycycline |
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Which bugs are covered by cephalexin or cefazolin?
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First gen cephalosporins
Gram positive cocci and PEcK (Proteus, E. coli, and Klebsiella) |
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Which bugs are covered by cefprozil?
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Second generation cephalosporins
Gram positive cocci plus HEN PEcKS H. flu type B, Enterobacter, Neisseria, Proteus, E. coli, Klebsiella, Serratia |
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Which bugs are covered by cefdinir and ceftriaxone?
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Serious gram negative infections resistant to other beta lactams; meningitis (S. pneumo), pseudomonas, gonorrhea.
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What bugs are covered by cefepime?
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Fourth generation cephalosporin
Increased activity against gram positive organisms and Pseudomonas |
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What stain would you use for Treponemes?
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Darkfield microscopy and fluorescent antibody staining
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Antibodies to which protein of Streptococcus pyogenes (group A streptococci) enhance host defenses but can give rise to rheumatic fever?
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M protein
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What is the function of protein A of staph aureus?
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Binds Fc region of Ig. Prevents opsonization and phagocytosis.
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What is the MOA for Vibrio cholerae toxin?
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Permanently activates Gs, increasing cAMP, and causing rice water stools.
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What is the MOA for Vibrio pertussis toxin?
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Permanently disables Gi, increasing cAMP, and causing whooping cough.
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What is the MOA of Bacillus anthracis toxin?
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Bacillus anthracis toxin includes edema factor, a bacterial adenylate cyclase (increases cAMP).
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What are the symptoms of rheumatic fever?
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No "rheum" for SPECCulation:
Subcutaneous plaques, Polyarthritis, Erythema marginatum, Chorea, and Carditis |
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Which type of steptococcus can grow in 6.5% NaCl?
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Enterococci
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Which bacteria is associated with bacteremia and subacute endocarditis in colon cancer?
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Streptococcus bovis
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What medium is used to grow diphtheria?
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Tellurite agar
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Which bacteria form spores?
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Only certain gram positive rods - Bacillus anthracis, Clostridium perfringens, C. tetani, B. cereus, and C. botulinum.
Spores have dipicolinic acid in their core. |
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Tetanospasmin
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An exotoxin produced by Clostridium tetani which blocks glycine release from Renshaw cells in the spinal cord. Causes spastic paralysis, trismus (lockjaw), and risus sardonicus.
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What is the only bacteria with a polypeptide capsule?
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Bacillus anthracis has a capsule that contains D-glutamate.
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What is the only gram positive bacteria with endotoxin?
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Listeria
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What are the possibilities if a PPD comes back positive?
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Current TB infection, past TB infection, or BCG vaccination
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Mycobacterium kansasii
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Found in patients with chronic bronchitis or COPD; produces TB like pulmonary symptoms.
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Mycobacterium avium intracellulare
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Often resistant to multiple drugs; causes disseminated disease in AIDS.
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Mycobacterium scrofulaceum
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Causes cervical lymphadenitis in children.
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Mycobacterium marinum
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Aquatic; causes osteomyelitis, arthritis, and cellulitis in patients that work in shipyards or aquarium handlers.
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What is the reservoir for Mycobaterium leprae in the United States?
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Armadillos
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What is the treatment for Hansen's disease?
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Leprosy; treatment is long term oral dapsone (toxicity is hemolysis and methemoglobinemia). Alternate treatments include rifampin and combination of clofazimine and dapsone.
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What would you give for prophylaxis in close contracts with someone who had contracted meningococcus infection?
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Rifampin
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What causes pontiac fever?
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Legionella pneumophila; it is a mild flu-like syndrome.
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What are the toxins produced by Pseudomonas?
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endotoxin (fever, shock) and exotoxin A (inactivates EF-2)
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Which strain of E. coli causes bloody diarrhea and fever?
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EIEC
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Salmonella typhi
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Causes typhoid fever - fever, diarrhea, headache, rose spots on abdomen. Can remain in the gallbladder chronically.
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Yersinia enterocolitica
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Usually transmitted from pet feces, contaminated milk, or pork. Outbreaks are common in day-care centers. Can mimic Crohn's or appendicitis, especially in adolescents.
LLQ or RLQ pain with fever. |
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Which bacteria are spirochetes?
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BLT
Borrelia, Leptospira, and Treponema |
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Treponema pertenue
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Causes yaws - infection of the skin, bone, and joints, healing with keloids, and severe limb deformities after 5-10 years. Disease of the tropics. Not an STD, but VDRL positive.
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What are the symptoms of congenital syphilis?
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Saber shins, saddle nose, CN VIII deafness, Hutchinson's teeth, mulberry molars, and frontal bossing
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What causes bacillary angiomatosis?
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Bartonella hensli
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What causes undulant fever?
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Brucella
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What is the classic triad of Rickettsiae infection?
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Headache, fever, and rash (vasculitis)
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What infections cause a rash seen on palms and soles?
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Coxsackie A infection, Rocky Mountain Spotted Fever, and Syphilis
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Chlamydia psittaci
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Causes psitticosis, a lung disease that can spread systemically. Notable for an avian reservoir.
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Which bacteria has a cell wall that is lacking muramic acid?
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Chlamydiae species
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What is the only bacteria whose cell membrane contains cholestrol?
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Mycoplasma
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How does congenital toxoplasmosis present?
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Chorioretinitis, hydrocephalus, and intracranial calcifications
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