Microbiology Lab ASCP exam
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Anaerobic specimens- unacceptable
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Throat, sputum, genital
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Media selection: throat
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BAP, CNA, (SXT)
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Media selection: Urine
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BAP, Mac, (CNA)
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Media selection: Wound
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BAP, CHOC, Mac
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Media selection: Sputum
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BAP, Mac, Choc, CNA
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Media selection: Genital
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Choc, MTM
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Media selection: CSF
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Choc, BAP, broth
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Media selection: Blood
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Broth
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Boricon Tubes
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Urine
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Jembec plate
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MTM for Neisseria gonnorheae
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Enterobacteriaceae
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gram neg bacilli oxidase negative Ferments Glucose Reduces nitrate to nitrite Mac agar- selective from gneg and differential for lactose ferment
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Spot indol
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organism forms indol from tryptophan negative: enterobacter, Klebsiella, P. mirabalis, enterobacteriaceae - absence of blue Positive/pink: E. coli, Aeromonas, Proteus spp, Flavobacterium
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Oxidase Test
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bacterial colonies having cytochrome oxidase develop blue color Neg - enterobacteriaceae Pos - Aeromonas, Pseudomonas, Neisseria
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Triple Sugar Iron Agar (TSI)
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Yellow butt (acid) - ferments glucose Red Butt (alkaline) - no glucose fermentation yellow slant (acid) - lactose, sucrose or both Red slant (alkaline) - non lactose or sucrose utilization Gas: breaks in agar Black: H2S
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TSI - Salmonella typhi TSI - Salmonella sp. TSI - Shigella TSI - Proteus vulgaris TSI- Proteus mirabilis TSI - Klebsiella TSI - E. coli
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K/A no gas, H2S+/- no urea K/A, gas, H2S pos no urea K/A, no gas, no H2S no urea K(or)A/A, gas H2S Pos UREA K/A, gas, H2S pos UREA A(or)K, gas, H2S neg UREA A/K, +/- gas, no H2S no urea
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Haemophilus influenzae Haemophilus parainfluenzae Haemophilus hemolyticus
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Needs XV, -ALA Needs V, +ALA Needs XV, +ALA, hemolysis on quad
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Beta lactamase Test
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Nitrocefin disk (cephalosporin) Positive: pink red Negative: no color change
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X & V Requirements Test
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X factor: hemin, hematin V factor: NAD
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DNase
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Positive= clearing Staphlylococcus aureus Negative =
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slide Coagulase
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Bound coagulase - protein with prothrombinlike activity to differentiate S. aureus from other Staph. * 2 minute test
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tube coagulase
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Free coagulase - protein with prothrombinlike activity incubate 35C for 4 hours reincubate 25C and read after 18 hours Differentiate S. aureus from other Staph
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Catalase
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converts H2O2 O2 and H20 Differentiates Micrococcaceae (Staph) Positive Streptococcus = Negative Enterococcus faecalis = tiny bubbles
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Staph isolation plates
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BAP, CNA, Mannitol salt agar
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Novobiocin susceptibility test
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S. saprophyticus = resistant = no zone of inhibition CNS/ S. aureus = sensitive = 16 mm zone or larger
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Staph Latex
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Latex with fibrinogen particles, IgG and specific anticapsular monoclonal antibodies Positive = S. aureus organisms
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Staph identification tests
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Catalase, DNase, Coagulase, novobiocin, Latex GPC,
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Streptococcus isolation plates
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BAP, SXT, CNA
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Streptococcus identification tests
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Catalase, Bile esculin, sodium chloride tolerance, Camp, Spot CAMP, Optochin, Bile solubility, Bacitracin, Hippurate hydrolysis, PYR, latex
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Bile esculin
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Group D Streptococci hydrolize esculin in presence of 4% bile salts Positive (dark) = Enterococcus faecalis = Streptococcus bovis (Group D Non-entero) Negative (not dark) = Gamma strep no Group D
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Sodium Chloride Tolerance
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Ability to grow in 6.5% NaCl Positive (turbid) = Enterococcus faecalis Negative=S. bovis (Group D Non-enterococci), Gamma Strep not D
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Camp
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Positive (arrow) = Group B Strep negative = Group A strep
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Optochin susceptibility test (taxo P discs)
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Selectively inhibits the growth of S. pneumoniae Positive (zone) = Strep. pneumo negative (no zone) = Strep viridans
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Bile solubility
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Disappearance of the tested colonies - hydrolyzed area Positive = S. pneumoniae
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Bacitracin susceptibility test
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Positive (zone) = group A Beta hemolytic Strep negative (no zone) = non-Group A Beta hemolytic Strep
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Catalase
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Positive = Staph Negative = Strep
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Hippurate Hydrolysis
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Enzyme hippuicase hydrolyses Na hippurate to benzoic acid and glycine Positive (Purple) = Group B Strep, (gardnerella vaginalis, campy) Negative (clear) = Group A Strep
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PYR
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Hydrolyzed by the amino peptidase enzyme Positive (pink/red)= Enterococcus (Strep. faecalis), Beta Strep Group A Negative (yellow/orange) =Alpha Strep (Strep. viridans,) S. bovis (group D non-enterococcus)
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Strep Grouping Test: A, B, C, F, G
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Latex agglutination with group specific antibodies and cell wall antigens
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Plate CAMP Test
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Hemolytic activity of S. aureus is enhanced by extracellular protein produced by Beta Strep Group B Arrow = Beta Strep GroupB No arrow = Beta Strep group A
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Neisseria gonorrhoeae Neisseria meningitidis Moraxella
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Growth on MTM/Choc Diplococci Oxidase +
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Throat Urine sputum wound
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Beta Strep A S. aureus, S. sapro, E. faecalis, Enterobacteriaceae S. pneumo, Pseudomonas, Haemophilus, Neisseria Anything
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Kirby-Bauer Test
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Qualitative value - no MIC Sens, Intermediate, Resistant
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Kirby-Bauer with epsilometer test
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MIC Value
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MIC
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determined by observing the lowest antimicrobial concentration showing an inhibition of growth.
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Catarrhalis Disk
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Positive (blue) = M. catarrhalis Negative = N. gonorrhoeae
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MiniTek
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N. gonorrhoeae + --- N. meningitidis ++-- N. lactamica +++- M. catarrhalis ++++
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Gram Positive Bacilli
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Listeria monocytogenes Erysipelothrix rhusiopathiae Corynebacterium diphtheriae Bacillus sp. Lactobacillus sp.
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Listeria sp. tests (GPB)
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bile - esculin tube motility
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Erysipelothrix (GPB)
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TSI
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Catalase -GPB
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Listeria monocytogenes Erysipelothrix rhusiopathiae Corynebacterium diphtheriae Bacillus sp.
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Gram Pos Bacillus isolation plates
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BAP, CNA - columbia
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Hydrogen Sulfide Production
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H2S reacts with iron salks to produce black precipitate ferric sulfide E. rhusiopathiae +
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Loeffler's Serum Medium
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isolates C. diphtheriae but is non-selective produces cells with metachromatic granules when stained with methylene blue stain
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Serum Tellurite agar
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Corynebacterium dephtheriae will appear as brown-black colonies with intense halo *selective and differential
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Mycobacteriology decontamination
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Mucolytic agent: 15 min 1. NALC - frees mycobacteria trapped in mucus 2. NaOH 4% 3. TSP 13% 4. Oxalic acid 5% 5. Clorox beach - used to prepare spec for AFB smear ONLY
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Mycobacteria medium
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Lowenstein-Jensen Petragnani Middlebrook 7H10, 11, 12
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Mycobacteria staining
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Acid Fast staining: ziehl-neelsen, kinyoun's cold, aura mine fluorochrome
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Anaerobic bacateria
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Bacteroides Clostridium
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Double zone of hemolysis
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Clostridium perfringens
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microscopic preparations for mycology
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Lactophenol cotton blue Periodic acid-schiff stained smear KOH prep
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Tube urease
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Enzyme by Cryptococcus neoformans that can hydrolyse urea to ammonia and CO2. Increase in pH is detected by indicator phenolphalein.
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C. albicans screen
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Positive: PRO+ and NGL+
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Germ Tube Test
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Positive: C. albicans Negative: C. tropicalis
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Gram positive Bacilli
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Corynebacterium Lactobacillus E. rhusiopathiae Bacillus Listeria
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Gram positive Cocci
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Strep Staph
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Gram neg bacilli
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Gardnerella Legionella A. actinomycetmcomitans Eikenella Vibrio C. j jejuni Yersinia pestis Enterobacteriaceae Klebsiella B. pertussis Haemophilus
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Gram neg cocci
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Neisseria (diplo) Moraxella (cocco)
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D-ALA Porphryin Test
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ALA disc Rxn: orange red fluorescence Screens: H. influenzae, H. parainfluenzae, H. haemolyticu
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Bacitracin
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Bacitracin disc from blood agar Rxn: zone Screen: Beta Strep group A
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Bile Esculin
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Bile Esculin agar tubes Rxn: Blackening Screen: Group D Streptococci
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Catalase
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Hydrogen peroxide Rxn: bubbles Screen: Micrococceae Staph +, Strep neg, Enterococcus +/-
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Esculin Hydrolysis Test
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Esculin Disc Rxn: dark, no fluorescence Screens: Enterococci +, Beta Strep group A neg
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Rapid hippurate Test
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Hippurate disc, nihydrin reagent Rxn: purple color Screens: Beta strep Group B, Gardnerella, Campy +
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Na Hippurate
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Rxn: Purple color in tube Screens: Beta Strep Group B +, Beta Strep Group A neg
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Novobiocin Test
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Discs, 0.5 McFarland Rxn: Zone Screens: Staph. saprophyticus +, Coag Neg Staph - neg
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Optochin Test
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Taxo discs on Blood agar plate Rxn: zone Screens: Strep. pneumo, Strep viridans (group A) neg
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Pathodex Strep grouping
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Latex A, B, C, F, G Rxn: Agglutination Screens: Streptococcus typing
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PYR
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Disc Rxn: pink/red in 1 minute screens: Enterococcus faecalis +, Alpha Strep viridans neg,
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Salt Tolerance
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Heart infusion broth Rxn: growth Screens: Enterococci faecalis +, Group D neg
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Plate CAMP test
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Blood agar, Staph aureus, beta Strep B, beta Strep A Rxn: arrow head hemolysis Screens: Beta strep Group B +, Beta strep Group A
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Bile solubility
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Na deoxycholate, bile salts, dreft Rxn: hemolysed area screen: Strep. pneumo +
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Tube coagulase
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rabbit plasma Rxn: clot at 4, 18 hours screens: S. aureus +, Coag Neg staph neg
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Pastorex Latex
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reagent latex Rxn: agglutination Screens: Staph aureus +, CNS neg
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Slide coagulase
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rabbit plasma Rxn: agglutination 10-15 sec Screens: S. aureus +, Coag Neg Staph neg
