MLS Micro Exam 3

Neisseria gonorrhoeae CTA Sugars

Fermentation of glucose only

Neisseria gonorrhoeae growth requirements

Immediate plating, room temperature, CO2 incubator

Neisseria gonorrhoeae media

Chocolate, NYC, modified Thayer Martin, Martin Lewis 

Neisseria gonorrhoeae complications

Direct smear not reliable for diagnosis in women, women harbor NGUF that resemble gm neg diplococci, specimens fragile- plating must happen quickly

Neisseria gonorrhoeae colony morphology

small, flat, brown, sticky, sweet smell

Neisseria gonorrhoeae gram stain

Gram-negative intracellular diplococci

E. coli MAC colony morphology

Pink, flat, LF colonies

E. coli HEK colony morphology

Orange, flat, LF colonies

E. coli indole result

positive

E. coli MR result

positive

E. coli VP result

negative

E. coli citrate result

negative

E. coli TSI result

A/A (G) or K/A (G)

E. coli LIA result

K/A

E. coli urease result

Negative

E. coli motility result

positive

E. coli gram stain

Gram-negative rods

What kind of E. coli causes traveller’s diarrhea?

ETEC (Enterotoxigenic E. coli)

What kind of E. coli is the most common to cause illness in people?

Enterohemorrhagic E. coli (0157:H7)

Proteus vulgaris colony morphology

NLF, swarms across plates

Proteus vulgaris indole result

positive

Proteus vulgaris MR result

positive

Proteus vulgaris VP result

negative

Proteus vulgaris citrate result

negative

Proteus vulgaris motility result

positive

Proteus vulgaris TSI result

K/A (G) H2S

Proteus vulgaris urease result

positive

Morganella motility result

positive

Morganella MR result

positive

Morganella indole result

positive

Morganella urease result

positive

Morganella TSI result

K/A

Edwardsiella motility result

positive

Edwardsiella MR result

positive

Edwardsiella indole result

positive

Edwardsiella urease result

negative

Edwardsiella TSI result

K/A (G) H2S

Proteus mirabilis motility result

positive

Proteus mirabilis MR result

positive

Proteus mirabilis indole result

negative

Proteus mirabilis urease result

positive

Proteus mirabilis TSI result

K/A (G) H2S

Citrobacter freundii motility result

positive

Citrobacter freundii MR result

positive

Citrobacter freundii indole result

negative

Citrobacter freundii urease result

50/50 negative/positive

Citrobacter freundii TSI result

A/A (G) H2S

Salmonella motility result

positive

Salmonella MR result

positive

Salmonella indole result

negative

Salmonella urease result

negative

Salmonella TSI result

K/A (G) H2S

Salmonella LIA result

K/K H2S

Serratia motility result

positive

Serratia MR result

negative

Serratia citrate result

positive

Serratia TSI result

K/A

Enterobacter cloacae motility result

positive

Enterobacter cloacae MR result

negative

Enterobacter cloacae citrate result

positive

Enterobacter cloacae TSI result

A/A (G)

Klebsiella aerogenes motility result

positive

Klebsiella aerogenes MR result

negative

Klebsiella aerogenes citrate result

positive

Klebsiella aerogenes TSI result

A/A (G)

Klebsiella pneumoniae motility result

negative

Klebsiella pneumoniae citrate result

positive

Klebsiella pneumoniae VP result

positive

Klebsiella pneumoniae indole result

negative

Klebsiella pneumoniae TSI result

A/A (G)

Klebsiella oxytoca motility result

negative

Klebsiella oxytoca citrate result

positive

Klebsiella oxytoca VP result

positive

Klebsiella oxytoca indole result

positive

Klebsiella oxytoca TSI result

A/A (G)

Shigella motility result

negative

Shigella citrate result

negative

Shigella TSI result

K/A

Shigella LIA result

K/A

Yersinia motility result

negative

Yersinia citrate result

negative

Yersinia TSI result

K/A or A/A

Shigella colony morphology

Flat NLF colonies

Non-fermenter characteristics

Aerobic, slow growers, 

Pseudomonas aeruginosa gram stain

long, thin, gram-negative rods

Pseudomonas aeruginosa colony morphology (BAP)

flat, irregular edge, gray-green, silver sheen, beta hemolytic, may be mucoid. Corn tortilla or grape odor

Pseudomonas aeruginosa colony morphology (MAC)

May not grow on MAC, if it does it will be flat NLF

Pseudomonas aeruginosa TSI result

K/K, silver sheen

Non-fermenter biochemicals

Oxidase, motile, OF glucose, Tech agar, TSI

Non-fermenter antibiotics used

aminoglycosides, colistin, meropenem, ceftazidime, tazobactam

Urine possible contaminating organisms

Strep viridans, Diptheroids, Lactobacillus, Yeasts, Staphylococcus, Gram negative bacilli (for S. aureus and GNB- only considered NGUF is quantity is less than other GP or NGUF organisms present)

Urinary tract common pathogens

E. coli, Klebsiella, Proteus, Pseudomonas aeruginosa, S. aureus, Staph saprophyticus, Enterococcus, Strep agalactiae,

Quantitation of NGUF in a clean catch urine specimen

Growth of >3 organisms, one or two present each < 10K

Quantitation of contamination in a clean catch urine specimen

3 or more organisms not consistent with skin or genital tract, 50-100k NGUF and >100k pathogen

Quantitation of a pathogen in a clean catch urine specimen

One organism >10k, two organisms each >10k, <50k NGUF w/ >50k pathogen

Urine specimen storage

Specimens collected into sterile containers may be refrigerated for 24h, in transport containers hold at RT use within 2h

Urine collection methods

clean catch, catheterized, suprapubic aspiration

Salmonella diseases

Typhoid fever, gastroenteritis, enteric fever, bacteremia

Shigella diseases

Bacillary dysentary, diarrheal illness

Shigella serotypes

A- dysenteriae

B- flexneri

C- boydii

D- sonnei

(Dirty Fingers Bring Shigella)