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175 Cards in this Set
- Front
- Back
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What organisms do not Gram stain well?
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Treponema (Darkfield and fluorescent Ab), Rickettsia (intracellular), Mycobacteria (acid fast), Mycoplasma (no cell wall), Legionella (Usually intracellular; silver stain), Chlamydia (intracellular and lacks muramic acid in cell wall)
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What organisms do you stain with Giemsa?
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Borrelia, Plasmodium, trypanosomes, Chlamydia
(BORING PLASTICS TRY CHLAMYDIA) |
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What organisms do you stain with PAS?
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Whipple's disease (Tropheryma whippleii). Stains glycogen, mucopolysaccharides
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What organisms do you stain with Ziehl-Neelsen?
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Acid-fast organisms
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What organisms do you stain with India Ink?
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Cryptococcus neoformans (mucicarmine can be used to stain thick polysaccharide capsule red)
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What organisms can you stain with Silver stain?
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Fungi (Pneumocystis), Legionella
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What culture requirements does H. influenzae have?
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Chocolate agar with factors V (NAD+) and X (hematin)
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What culture requirements does N. gonorroeae have?
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Thayer-Martin (or VPN) media- Vancomycin (inhibits GP organisms), Polymyxin (inhibits GN organisms), and Nystatin (inhibits fungi)
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What culture requirements does B. pertussis have?
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Gordet-Gengou (potato) agar
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What culture requirements does C. diphtheriae have?
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Tellurite plate, Loffler's media; Forms black colonies
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What culture requirements does M. tuberculosis have?
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Lowenstein-Jensen agar
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What culture requirements does M. pneumoniae have?
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Eaton's agar (needs cholesterol)
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What culture requirements do lactose-fermenting enterics have?
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Pink colonies on MacConkey's agar (turns the plate pink); E. coli is grown on eosin-methylene blue (EMB) agar as blue-black colonies with metallic sheen.
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What culture requirements does Legionella have?
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Charcoal yeast extract agar buffered with cysteine
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What culture requirements do fungi have?
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Sabouraund's agar
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What organisms are obligate aerobes?
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Nocardia, Pseudomonas aeuginosa, Mycobacterium tuberculosis, Bacillus
Nagging Pests Must Breath |
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What organisms are obligate anaerobes?
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Clostridium, Bacteroides, Actinomyces (lack catalase and/or superoxide dismutase and are susceptible to oxidative damage. Generally foul smelling (SCFA), difficult to culture, and produce gas in tissue (CO2 and H2). Cannot use aminoglycosides because these antibiotics require O2 to get into the bacterial cell.
Can't Breath Air |
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What organisms are obligate intracellular bugs?
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Rickettsia, Chlamydia, and USUALLY Legionella. Can't make ATP
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Facultative intracellular
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Salmonella, Neisseria, Brucella, Mycobacterium, Listeria, Francisella, Legionella
Some Nasty Bugs May Live FacultativeLy |
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What organisms are encapsulated?
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Strep pneumo, Klebsiella, H. influenzae type B, N. meningitidis, Salmonella, Group B strep. Their capsules are antiphagocytic and produce a positive Quellung reaction
Some Killers Have Nice Shiny Bodies; Remember that asplenic patients will frequently be infected with these! |
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What organisms are urease positive?
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Proteus, Klebsiella, H. pylori, Ureaplasma
Particular Kinds Have Urease |
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What organisms produce pigment?
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Actinomyces israelii (yellow), S. aureus (yellow), Pseudomonas (blue-green), Serratia marcescens (red)
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What organisms produce IgA protease?
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S. pneumo, H. influenzae type B, Neisseria (SHiN)
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What bugs produce superantigens?
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S. aureus- TSST-1 causes toxic shock syndrome, enterotoxins cause food poisoning, exfoliatin causes SSSS
S. pyogenes- Scarlet-fever erythrogenic toxin causes toxic shock-like syndrome |
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What bugs produce ADP-ribosylating A-B toxins?
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C. diphtheriae- Inactivates EF2 and causes pharyngitis and "pseudomembrane" in throat.
V. cholerae- Stimulates AC and increases the pumping of Cl into the gut and decreases Na absorption (rice water diarrhea) E. coli- HT stimulates AC; ST stimulates GC B. pertussis- Inhibits Gi to increase cAMP and cause whooping cough; inhibits chemokine receptor, causing lymphocytosis |
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What exotoxin does C. perfringens produce?
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alpha toxin- lecithinase that acts as a phospholipase to cleave cell membranes and cause gas gangrene. Double zone of hemolysis on blood agar.
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What does the exotoxin produced by C. tetani do?
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Blocks the release of GABA and glycine to cause "lockjaw"
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What does the exotoxin produced by C. botulinum do?
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Blocks the release of Ach to cause anticholinergic symptoms, CNS paralysis. Spores are found in canned food and honey (floppy baby syndrome)
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What exotoxin does B. anthracis produce?
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Edema factor- AC
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What exotoxin does Shigella produce?
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Shiga toxin cleaves host cell rRNA (inactivates 60S ribosome), causes cytokine release (HUS)
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What exotoxin does S. pyogenes produce?
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Streptolysin O is a hemolysin; antigen for ASO antibody, which is used in the diagnosis of rheumatic fever.
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What toxins are cAMP inducers?
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V. cholerae (permanently activates Gs), Pertussis (permanently disables Gi), ETEC heat-labile toxin, B. anthracis edema factor (an adenylate cyclase itself- NOT by ribosylation of endogenous AC)
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What bacteria exhibit transformation?
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S. pneumoniae, H. influenzae type B, Neisseria (SHiN)
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What bacterial toxins are encoded in a lysogenic phage?
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ShigA-like toxin, Botulinum toxin, Cholera toxin, Diphtheria toxin, Erythrogenic toxin of S. pyogenes
(ABCDE) |
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How do you differentiate between Staphylococcal species?
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S. aureus is coagulase positive
S. epidermidis is novobiocin sensitive and coagulase negative S. saprophyticus is novobiocin resistant and coagulase negative |
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How do you differentiate between alpha hemolytic Streptococcal species?
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S. Viridans is optochin resistant and S. pneumoniae is optochin sensitive
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How do you differentiate between beta hemolytic bacteria?
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S. pyogenes is bacitracin sensitive, catalase negative
S. aureus is catalase and coagulase positive S. agalactiae is catalase negative and bacitracin negative L. monocytogenes has tumbling motility, causes meningitis in newborns, and can be contracted from unpasteurized milk |
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What bacteria ferment lactose?
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Citrobacter, Klebsiella, E. coli (produces beta-galactosidase), Enterobacter, Serratia
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Haemophilus influenzae
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Small GNR, aerosol transmission, most invasive disease is caused by capsular type B, produces IgA protease, cultured on chocolate agar and requires factors V (NAD+) and X (hematin) for growth or can be grown with S. aureus (provides factor V). Causes Epiglottitis (cherry red in children), meningitis (treat with ceftriaxone), otitis media, pneumonia, treat close contacts with rifampin. DOES NOT CAUSE FLU!
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Klebsiella
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Intestinal flora that causes lobar pneumonia in alcoholics and diabetics when aspirated. Red currant jelly sputum. Also causes nosocomial UTIs. 4 As (Aspiration pneumonia, abscesses in lungs, alcoholics, diAbetics)
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E. Coli- EIEC
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Produces Shiga-like toxin, invades the intestinal mucosa and toxin causes necrosis and inflammation. Presents as dysentery
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E. Coli- ETEC
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Labile toxin/stabile toxin. No inflammation or invasion. Presents as traveler's diarrhea (watery).
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E. coli- EPEC
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No toxin produced. Adheres to apical surface, flattens villi (stacked brick- aka enteroaggregative), prevents absorption. Presents as diarrhea, usually in children (Pediatrics)
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E. coli- EHEC
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O157:H7 is the most common serotype. Produces Shiga-like toxin and Hemolytic-uremic syndrome (triad of anemia, thrombocytopenia, and acute renal failure). The endothelium swells and narrows lumen, leading to mechanical hemolysis and reduced renal blood flow; damaged endothelium consumes platelets. Presents as dysentery (toxin alone causes necrosis and inflammation) and does NOT ferment sorbitol (distinguishes from other E. coli)
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What GP bacterium has LPS?
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Listeria
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What GN bacterium does NOT have LPS?
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Nisseria- Has LOS
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What is the main virulence factor for S. aureus?
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Protein A- Binds Fc-IgG to inhibit complement fixation and phagocytosis (and opsonin)
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What is the main virulence factor for S. pneumo?
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Capsule; also produces IgA protease
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What is the major virulence factor for S. pyogenes?
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M protein- and this is what we make antibodies to that causes rheumatic fever.
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How can you differentiate enterococci and nonenterococci (Group D strep)?
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Enterococci- Grow in bile AND 6.5% NaCl
Nonenterococci- Grow in bile but NOT in 6.5% NaCl |
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How is C. diphtheria diagnosed?
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GPR with metachromatic granules!!!
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How do you kill spores?
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Steam at 121oC for 15 minutes
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What is at the core of the spore?
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Dipicolinic acid
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What toxins does C. difficile produce?
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1. Toxin A- Binds brush border of gut and is a chemoattractant; causes inflammation and water loss
2. Toxin B- Cytotoxic by destroying cytoskeletal structure of the enterocytes (depolymerizes actin) and forms a pseudomembrane |
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Which bacterium has a polypeptide capsule?
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Bacillus anthracis (has D-glutamate)
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What toxin does B. anthracis produce?
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Edema factor, Lethal factor
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Which GP organism is weakly acid fast?
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Nocardia
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What is the viurlence factor for mycobacteria?
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Cord factor- inactivates neutrophils, damages mitochondria, and releases TNF; causes bacteria to grow in a serpentine fashion
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Which form of Hansen's disease is worse?
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Lepromatous type
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What type of media does vibrio grow in?
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Alkaline
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Which bacteria ferment lactose?
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Citrobacter, Klebsiella, E. coli, Enterobacter, Serratia
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What ferments glucose and maltose?
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N. meningitidis
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What ferments only glucose and not maltose?
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N. gonororhea
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What is the H. flu vaccine conjugated to?
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Diphtheria toxoid
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What toxin does Pseudomonas produce?
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Exotoxin A- inactivates EF-2 (like Corynebacterium)
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What is the virulence factor for E. coli that cause cystitis and pyelonephritis?
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Fimbrae
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What is the virulence factor for E. coli that cause pneumonia and neonatal meningits?
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K capsule
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What is the virulence factor for E. coli that cause septic shock?
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LPS
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What strains of E. coli produce Shiga-like toxin?
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EIEC (invasive), EHEC
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Which strain of E. coli does NOT ferment sorbitol and does not produce glucoronidase?
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EHEC
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What causes mesenteric adenitis that can mimic Crohn's disease or UC?
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Yersinia enterocolitica
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What is triple therapy for H. pylori?
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Metronidazole + Bismuth + tetracycline or amoxicillin
Metronidazole + Omeprazole + clarithromycin (more expensive) |
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Which bacteria uses Mn instead of Fe as a cofactor?
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Borrelia burgdorferi (Lyme disease)
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What are signs of tertiary syphilis?
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Broad-based ataxia, positive Romberg (dorsal columns), Charcot joint, stroke without hypertension
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What can cause a false positive VDRL test?
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Viral infection (mono, hepatitis)
Drugs Rheumatic fever SLE Leprosy |
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What is transmitted by the louse?
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Borrelia recurrentis (relapsing fever)
Rickettsia prowazekii (typhus) |
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What is transmitted by the Ixodes tick?
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Borrelia burgdorferi, Babesia, Anaplasma
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What is transmitted through unpasteurized dairy?
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Brucella (undulant fever)
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What is transmitted through flee bites, rodents, and prarie dogs?
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Yersinia pestis
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What is the classic triad seen in Rickettsial infection?
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Headache, fever, rash (vasculitis)
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Where is the rash of RMSP (R. rickettsii) vs Typhus (R. prowazekki)
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Rickettsia on the wrists (hands and feet), Typhus on the Trunk
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What rashes are on the palms and soles?
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Tertiary syphilis, RMSF, HFMD
Peeling of palms and soles- Mercury (acrodynia), Kawasaki disease |
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What is the Weil-Felix reaction
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Proteus antigens are mixed into a patients serum so that antirickettsial antibodies cross react to Proteus O antigens and agglutinate (NEGATIVE IN COXIELLA)
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Where is Histoplasmosis seen?
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Mississippi and Ohio river valleys (associated with caves and bird/bat droppings)
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Where is Blastomycosis seen?
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States EAST of the Mississippi River and Central America
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Where can Blasto and Cocci disseminate?
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Skin and Bone
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Where is coccidioidomycosis seen?
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SW US, CA (San Joaquin Valley or desert)
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What are the 3 diseases caused by Aspergillus?
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1. Allergic bronchopulmonary disease (like asthma)
2. Lung cavity aspergilloma of prior lesions (old TB, neoplasm) 3. Invasive- seen in HIV and CGD |
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What produces "soap bubble" lesions in the brain?
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Crypto
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What produces a black necrotic eschar on facial cranial nerve?
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Mucor and Rhizopus spp.
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What produces fruiting bodies?
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Aspergillus
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What produces saucer-shaped yeast forms?
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PCP
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What produces cigar-shaped yeast forms?
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Sporothrix
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What produces acid fast cysts?
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Cryptosporidium- Watery diarrhea in AIDS, can infect water systems of cities
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What produces the triad of chorioretinitis, hydrocephalus, and intracranial calcification?
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Toxoplasma- neonatal
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How do you treat Toxoplasma?
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Sulfdiazine + pyrimethamine
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What enters through the cribiform plate?
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Mucor/Rhizpus spp.
Naegleria fowleri |
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How do you treat Trypanosoma brucei?
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Suramin for blood borne disease, Melarsorol for CNS (SURe is nice to go to sleep; MELAtonin helps with sleep)
Note: anitgenic variation |
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How do you treat Typanosoma cruzi?
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Nifurtimox
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What is associated with kala-azar
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Leishmania donovani
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How do you treat Leishmania donovani?
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Sodium stibogluconate
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Where are macrophages containing "amastigotes" found (lack flagella form)?
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Leishmania donovani
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How do you treat Babesia?
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Quinin, clindamycin
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What is transmitted by the Ixodes tick?
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B. burgdorferi
Babesia |
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What shows motile trophozoites on wet mount?
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Trichomonas vaginalis
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What does Trichinella spiralis do?
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Undercooked pork; inflammation of muscle (encyst), periorbital edema
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What helminth causes anemia?
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Hookwork (Ancylostoma duodenale, Necator americanus)
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How do you treat elephantiasis?
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Diethylcarbamazine
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What is transmitted by the black fly?
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Onchocerca- river blindness (black skin nodules, black sight, black fly)
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How do you treat T. solium?
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Praziquantel, bendazoles for neurocystericosis
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What causes an anphylaxis?
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Cysts of Echinococcus granulosus
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What nematodes are ingested?
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Enterobius, Ascaris, Trichnella
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What nematodes are cutaneous?
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Strongyloides, Ancylostoma, Necator
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What causes hemoptysis and is transmitted through undercooked crab meat?
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Paragonimus westermani
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What parasite can cause portal hypertension?
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Schistosoma mansoni
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What vaccines are live-attenuated?
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Smallpox, yellow fever, chickenpox, Sabin's polio virus, MMR (this one can be given to HIV-positive patients too), Francisella tularnensis, BCG (Tb)
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What vaccines are killed/inactivated?
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Rabies, Influenza, Salk polio, HAV
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What vaccines are recombinant?
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HBV, HPV
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What viruses are naked?
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Calcivirus, picornavirus, reovirus, parvovirus, adenovirus, papillomavirus, polyoma virus (naked CPR and PAPP smear)
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What DNA virus is NOT double stranded?
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Parvovirus- ss
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What DNA viruses are NOT linear?
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Papilloma and polyoma (circular, supercoiled), hepadenavirus (circular, incomplete)
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What DNA virus is NOT icosahedral and does NOT replicate in the nucleus?
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Poxvirus- complex and has its own DNA-dependent RNA polymerase!
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What viruses are segmented?
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Bunyaviruses
Orthomyxoviruses Arenaviruses Reovuses (rotavirus) All can undergo reassortment to cause worldwide pandemics (antigenic shift) |
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What is the only picornavirus that is NOT an enterovirus?
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Rhinovirus- labile at gastric pH; the rest are stable (Polio, Echo, Coxsackie, HAV)
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Which purified nucleic acids of viruses are infective?
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dsDNA (except pox and HBV) and +SS RNA; Naked nucleic acids of -SS RNA and dsRNA viruses are NOT infective (require enzymes contained in the complete virion to be infective!)
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Which RNA viruses do not replicate in the cytoplasm?
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Influenza virus, retrovirus
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What does Parvovirus B19 cause in adults?
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Rheumatoid arthritis like symptoms
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Where do each of the herpesviruses remain latent?
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HSV1- Trigeminal ganglia
HSV2- Lumbosacral ganglia VZV- Trigeminal and DRG EBV- B cells CMV- Mononuclear cells |
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What is associated with circulating "atypical lymphocytes?"
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EBV; actually just normal T cells reacting to EBV infected cells
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Which virus has RNA that is translated into 1 large polypeptide that is cleaved by proteases into functional viral proteins?
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Picornaviruses
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How does rotavirus cause gastroenteritis?
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It destroys villi, leading to decreased absorption of Na and water. Green diarrhea.
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What are patients with influenza virus at risk for?
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Fatal bacterial superinfection
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What do all paramyxoviruses contain on their surface?
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F protein- causes respiratory epithelial cells to fuse and form multinucleated cells.
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What causes giant cell pneumonia in the immunocompromised?
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Rubeola (measles)
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What causes parotitis, orchitis, and aseptic meningitis?
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Mumps virus
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Which virus should you give a prophylactic vaccination immediately upon exposure?
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Rabies
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Which virus has a bullet shaped capsid?
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Rabies
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Cytoplasmic inclusions in Purkinje cells of the cerebellum?
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Rabies
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What is the virion enzyme for HBV?
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DNA-dependent DNA polymerase
(uses host DNA-dependent RNA polymerase) |
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What is the only thing that's positive during the window period of HBV infection?
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Anti-HBcAg
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What indicates the presence of HBV infection?
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HBsAg
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What indicates immunity to HBV?
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Anti-HBsAg
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What are the 3 structural genes for HIV?
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env (gp 120 and gp41- cleaved from gp160)
gag (p24) pol (RT) |
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How do babies get a false positive ELISA screen?
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anti-gp120 antibodies from an infected mother can cross the placenta
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What is the first thing to rise in HIV infection?
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viral p24 antigen
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What is the transmissible form of prion disease?
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PrPsc (beta pleated form)
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What is the normal flora of the nose?
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S. epidermidis; colonized by S. aureus
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What is the normal flora of the colon?
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Bacteroides fragilis > E. coli
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What are the normal vaginal flora?
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Lactobacillus, colonized by E. coli and GBS
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What is founded in reheated meat dishes that causes food poisoning?
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C. perfringens
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What is associated with turtles?
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Salmonella
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What are the causes of bloody diarrhea?
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Campylobacter, Salmonella, EHEC, EIEC, C. diff, Entamoeba histolytica
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What are the causes of watery diarrhea?
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ETEC, cholera, C. perfringens, protozoa (Giardia, Cryptosporidium), Viruses (rotavirus, adenovirus, Norwalk virus)
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What are the most common causes of pneumonia in different age groups?
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Neonates (<4 weeks): GBS, E.coli, Listeria
Children (4 wks - 18 yrs): Viruses (RSV), Mycoplasma, Chlamydia pneumoniae, S. pneumo Adults (18-40): Myoplasma, C. pneumo, S. pneumo Adults (40-65): S. pneumo, H. flu, Anaerobes, viruses, Mycoplasma Elderly (>65): S. pneumo, Influenza, Anaerobes, H. flu, GNR |
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What are the normal vaginal flora?
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Lactobacillus, colonized by E. coli and GBS
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What bacteria commonly cause pneumonia post-virally?
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Staph, H. flu
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What is the most common nosocomial pneumonia?
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Staph, GNRs
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What are the most common causes of meningitis in neonates?
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GBS, E. coli, Listeria
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What are the most common causes of meningitis in children (6mo-6yrs)?
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S. pneumo, Neisseria, H. flu, Enteroviruses (Echo, Coxsackie)
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What are the most common causes of meningitis in 6-60 yrs?
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N. meningitidis, Enteroviruses, S. pneumo, HSV
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What are the most common causes of meningitis in >60?
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S. pneumo, GNRs, Listeria
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What are the most common causes of meningitis in HIV?
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Crypto, CMV, toxo, JC
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What is the MCC of osteomyelitis?
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S. aureus
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What indicates a GNR UTI?
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Positive nitrite test (EXCEPT S. saprophyticus)
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What causes "swarming" on agar?
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Proteus mirabilus because of motility
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What congenital infection causes hearing loss (unilateral), seizures, and petechial rash?
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CMV (MC TORCHES infection)
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What congenital infection causes chronic diarrhea and recurrent infections?
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HIV
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Childhood rash and postauricular LAD?
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Rubella
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Ulcers, LAD, rectal strictures?
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LGV
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Vaginitis, strawberry colored mucosa, corkscrew motility on wetmount?
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Trichomonas
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How do you tell Bartonella and HHV-8 lesions apart in HIV patients?
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Bartonella- neutrophilic inflammation
HHV-8- lymphocytic infiltration Both cause superficial vascular proliferation |
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Meningitis that leads to myalgia and paralysis in unimmunized kids?
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Polio
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What are the catalase positive organisms?
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S. aureus, Nocardia, Aspergillus (commonly infect CGD patients)
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What are neutropenic patients susceptible to?
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Candida (invasive), Aspergillus
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What bacteria invade the intestine?
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Salmonella, Shigella, EHEC, campylobacter, Entamoeba, EIEC
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