Exam #4 - Adv Clin Microbio (Lab)

Enterobacteriaceae: Gm, glucose, ox, nitrate, motility, media/morph (4)

• short, fat, non-spore forming Gram (-) rods (facultative anaerobes)

• all ferment glucose (+)

• all oxidase (-)

• all reduce nitrate → nitrite 

• all are motile except: Shigella, Klebsiella, Yersinia

• all grow well on routine media:

  • BAP: large grey, may be beta-hemolytic

  • CHOC: large grey

  • MAC: pink (LF) to clear/colorless (NLF)

  • HEK: orange to clear/colorless, some with black centers (H2S)

S. aureus: Gm, morph, tests (7)

• gram (+) cocci in clusters

• BAP: appears large, golden color, beta-hemolytic

• Coag (+), Cat (+), PYR (-), VP (+), bacitracin (S), erythromycin (S), 6.5% NaCl broth (+)

S. saprophyticus: Gm, morph, tests (4)

• Gram (+) cocci in clusters

• BAP: large colonies, range from very white to slightly pigmented; usually non-hemolytic

• coagulase (-), Novobiocin (R), Urease (+), polymyxin B (S)

S. epidermidis: Tests (2), Hemolytic activity, Gm

• Urease (+), Novobiocin (S)

• gamma-hemolytic

• Gm (+) cocci in clusters

Enterococcus sp.: Media, Gm, tests (6)

• BAP: small, flat, translucent, non-hemolytic

• MAC: NG

• Gram (+) cocci in pairs, short chains

• Cat & CAMP (-)

• PYR & Esculin (+)

• (R): bacitracin, SMZ, optochin

• (S): Vancomycin

Streptococcus Gp. A: Species, Gm, morph/media, tests (8)

• S. pyogenes

• Gram (+) cocci with short chains

• SBA (selective): small, transparent, and smooth with a well-defined area of beta-hemolysis

• (S): Vancomycin, bacitracin

• (R): SMZ, optochin

• (+): PYR

• (-): CAMP, bile esculin, 6.5% NaCl

Streptococcus Gp. B: Species, morph/media, Gm, tests (10)

• S. agalactiae

• SBA plate: greyish-white mucoid colonies with a small beta-hemolysis zone

• MAC: NG

• Gram (+) cocci in pairs and chains

• (S): vancomycin

• (R): bacitracin, SMZ, optochin

• (+): CAMP, leucine

• (-): PYR, Bile esculin, 6.5% NaCl, Cat

Streptococcus Gp. D: tests for identification

• (S): vancomycin

• (R): bacitracin, optochin

• (+): Leucine, bile esculin

• (-): PYR, CAMP, 6.5% NaCl

Streptococcus pneumoniae: tests (10), Gm, morph

• catalase (-)

• (S): vancomycin, bacitracin, SMZ, optochin

• (+): Leucine

• (-): PYR, CAMP, bile esculin, 6.5% NaCl

• Gram (+) cocci in chains and pairs

• green alpha-hemolytic zone

Strep viridans: Morph, test

• morph: small, dry, alpha-hemolytic

• MAC: NG

• Cat (-); NGUF

Micrococcus: Tests (5), Gm, morph

• catalase (+), coagulase (-)

• Bacitracin (S), (-) anaerobic acid production from glucose, (-) anaerobic acid production from glycerol in presence of erythromycin

• Gm (+) cocci

• Morph: produce yellow pigment

H. influenza: Growth requirements, Gm, morph, testing (2)

• needs factor X (hemin) & V (NAD) → Only grow on CHOC

• small, gram (-) coccobacilli; pleomorphic

• BAP/MAC: no growth; on CHOC: growth

• Porphyrin test and Satelliting require NAD (V) & Hemin (X)

Neisseria gonorrhoeae: Media, Gm, morph, tests (4)

• CHOC agar & selective media

  1. selective: Thayer Martin (TM), New York City (NYC), Martin Lewis (ML)

  2. requires O2

• Intracellular or extracellular Gram (-) diplococci

  1. diagnostic in males; not in women due to norm flora

• Gray, small, glistening, raised; does not grow on BAP

• oxidase (+)

• (+) for glucose only

• Susceptibility testing:

  • beta lactamase & disk diffusion

  • penicillin resistance is a major problem

  • quinolones & broad spectrum cephalosporins are drugs of choice

Nocardia: Gm, stains, morph

• Gm (+) branching rods, wet prep (on sulfur granules)

• Mod kinyoun: partially acid fast

• orange, glaborous, heaped, folded, may be white to pink, dry, crumbly

Streptomyces: Morph, odor

• leathery, heaped, folded, cream to brown to black with white chalky surface

• heavy odor of dirt

• Gm (+) extremely long rods