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Bacteriology

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navyy's version from 2017-08-30 18:23

Culture requirements

BugMedia
H. influenzaeChocolate agar with factors V (NAD+) and X (hematin)
N. gonorrhaeaeThayer-Martin (VPN) media - Vancomycin, Polymyxin, and Nystatin
B. pertussisBordet-Gengou (potato) agar
C. diptheriaeTellurite plate, Loffler's media
M. tuberculosisLowenstein-Jenson agar
M. pneumoniaeEaton's agar
Lactose-fermenting entericsMacConkey's agar (pink colonies b/c fermentation produces acid that turns plate pink), E. coli: EMB (eosin-methylene blue) agar as blue-black colonies with metallic sheen
LegionellaCharcoal yeast extract agar buffered with cysteine
FungiSabouraud's agar
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Stains

Question Answer
GiemsaBorrelia, Plasmodium, trypanosomes, Chlamydia
PASStains glycogen, mucopolysaccarides; diagnoise Whipple's disease (Tropheryma whippelii)
Ziehl-NeelsenAcid-fast organisms
India inkCyptococcus neoformans (also can use mucicarmine)
Silver stainFungi (Pneumocystis), Legionella
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Virulence factors

FactorBugFunction
Protein AS. aureusBinds Fc of Ig. Prevents opsonization and phagocytosis
IgA proteaseSHiN -- S. pneumoniae, H. influenzae type B, NeisseriaCleaves IgA and allows for colonization of respiratory mucosa
M proteingroup A strepHelps prevent phagocytosis
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Exotoxins

BugToxin and FunctionBad shit that happens afterwards
S. aureusSuperantigen -- TSST-1toxic shock syndrome (Helper-T)
S. aureusSuperantigen -- enterotoxinsfood poisoning
S. aureusSuperantigen -- exfoliatinscalded skin syndrome (protease)
S. pyogenesScarlet fever-erythrogenic toxintoxic shock-like syndrome
Corynebacterium diphtheriaeA-B toxin inactivating EF2 (elongation factor) - Protein synthesis Xcauses pharyngitis and psuedomembrane (throat, tonsils)
VibriocholeraeA-B toxin causing ADP ribosylation of G protein, stimulating adenylate cyclaserice-water diarrhea (pumping out Cl, and decreasing Na absorption)
E. coliHeat-labile toxin (adenylate cyclase)Watery diarrhea
E. coliHeat-stabile toxin (guanylate cyclase)Watery diarrhea
Bordetella pertussisA-B toxin, inhibits G-alpha-i (increasing cAMP), inhibits chemokine receptorwhooping cough, lymphocytosis
Clostriudium perfringinsalpha toxingas gangrene (double zone of hemolysis on blood agar)
C. tetaniInhibits release of GABA and glycineLockjaw, spastic paralysis, arched back
C. botulismInhibits release of AChanticholinergic sx, CNS paralysis, "floppy baby"
Bacillus anthracis3 components: Cell-bind protein (protective antigen) + Edema Factor + Lethal Factoradenylate cyclase, kills by blocking signal transduction
ShigellaShiga toxin, cleaves host cell rRNA and enhances cytokine releaseHUS
S. pyogenesStreptolysin Ohemolysis
Pseudomonas Aexotoxin A -- inactivates EF 2
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Gram positive bacteria (Cocci)

FindingBug
Catalase +, coag +, GoldenColonies (blood agar), Beta hemolysis, Menatol FermentStaph. aureus
Catalase +, coag -, novobiocin sensitive, non-hemolytic, Menatol non-fermentStaph. epidermis
Catalase +, coag -, novobiocin resistantStaph. saprophyticus
Catalase -, alpha hemolysis, capsule and optochin sensitive, bile solubleStrep. pneumo (pneumococci)
Catalase -, alpha hemolysis, no capsule, optochin resistant, not bile solubleViridans strep (s. mutans)
Catalase -, beta hemolysis, bacitracin sensitive, ELISA, ASO titer (rheumatic fever)group A strep (s. pyogenes)
Catalase -, beta hemolysis, bacitracin resistant, hydrolyze Hippurate, CAMP test +group B strep (s. agalactiae)
Catalase -, no hemolysisEnterococcus and Peptostreptococcus
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Gram negative bacteria

FindingBug
Cocci, maltose fermenter, Oxidase + (chocolate agar)N. meningitidis (Meningococcus)
Cocci, maltose non-fermenter, Oxidase +(Thayer-Martin Medium), Organism visible (Neutrophils - Urethral exudate), NAAT (screening)N. gonorrhoeae (Gonococci)
Coccoid rods (short rods)H. influenzae, Bordetella pertussis, Pasturella multocida, Brucella sp.
Rods, Lactose fermenter (fast)E. coli, Klebsiella, Enterobacter
Rods, Lactose fermenter (slow)Citrobacter, Serratia, Providencia, Arizona (Oppurtunist pathogens)
Rods, Lactose non-fermenter , Oxidase negativeShigella, Salmonella, Proteus
Rods, Lactose non-fermenter, Oxidase positivePsuedomonas
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Pigment producing bacteria

Question Answer
Gold/yellow pigmentstaph aureus
yellow "sulfur" granulesactinomyces
blue green pigmentpseudomonas
red pigmentserratia masrcescens
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