MICROBIO - Chapter 8.2 Flashcards
- Biochemically, Enterobacteriaceae spp. are gram (-) rods that:
A. Ferment glucose, reduce nitrate to nitrite, oxidase negative
B. Ferment glucose, produce indophenol oxidase, and form gas
C. Ferment lactose and reduce nitrite to nitrogen gas
D. Ferment lactose and produce indophenol oxidase
A. Ferment glucose, reduce nitrate to nitrite, oxidase negative
Ortho-nitrophenyl-β-galactopyranoside (ONPG) test is most useful when differentiating:
A. Salmonella spp. from Pseudomonas spp.
B. Shigella spp. from some strains of Escherichia coli
C. Klebsiella spp. from Enterobacter spp.
D. Proteus vulgaris from Salmonella spp.
B. Shigella spp. from some strains of Escherichia coli
Voges-Proskauer (VP) test detects which end product of glucose fermentation?
A. Acetoin
B. Nitrite
C. Acetic acid
D. Hydrogen sulfide
A. Acetoin
At which pH does the methyl red (MR) test become positive?
A. 7.0
B. 6.5
C. 6.0
D. 4.5
D. 4.5
A positive Simmons citrate test is seen as a:
A. Blue color in the medium after 24 hrs of incubation at 35°C
B. Red color in the medium after 18 hrs of incubation at 35°C
C. Yellow color in the medium after 24 hrs of incubation at 35°C
D. Green color in the medium after 18 hrs of incubation at 35°C
A. Blue color in the medium after 24 hrs of incubation at 35°C
In the test for urease production, ammonia reacts to form which product?
A. Ammonium citrate
B. Ammonium carbonate
C. Ammonium oxalate
D. Ammonium nitrate
B. Ammonium carbonate
Which of the following reagents is added to detect the production of indole?
A. p-Dimethylaminobenzaldehyde
B. Bromcresol purple
C. Methyl red
D. Cytochrome oxidase
A. p-Dimethylaminobenzaldehyde
Decarboxylation of the amino acids lysine, ornithine, and arginine results in the formation of:
A. Ammonia
B. Urea
C. Carbonate
D. Amines
D. Amines
Lysine iron agar (LIA) showing a purple slant and a blackened butt indicates:
A. Escherichia coli
B. Citrobacter spp.
C. Salmonella spp.
D. Proteus spp.
C. Salmonella spp.
Putrescine is an alkaline amine product of which bacterial enzyme?
A. Arginine decarboxylase
B. Phenylalanine deaminase
C. Ornithine decarboxylase
D. Lysine decarboxylase
C. Ornithine decarboxylase
Which genera are positive for phenylalanine deaminase?
A. Enterobacter, Escherichia, and Salmonella
B. Morganella, Providencia, and Proteus
C. Klebsiella and Enterobacter
D. Proteus, Escherichia, and Shigella
B. Morganella, Providencia, and Proteus
Kligler iron agar (KIA) differs from triple-sugar iron agar (TSI) in the:
A. Ratio of lactose to glucose
B. Ability to detect H2S production
C. Use of sucrose in the medium
D. Color reaction denoting production of acid
C. Use of sucrose in the medium
The malonate test is most useful in differentiating which members of the Enterobacteriaceae family?
A. Shigella
B. Proteus
C. Salmonella subgroups 2, 3 (the former Arizona)
D. Serratia
C. Salmonella subgroups 2, 3 (the former Arizona)
Which genera of the Enterobacteriaceae family are known to cause diarrhea and are considered enteric pathogens?
A. Enterobacter, Klebsiella, Providencia, and Proteus
B. Escherichia, Salmonella, Shigella, and Yersinia
C. Pseudomonas, Moraxella, Acinetobacter, and Aeromonas
D. Enterobacter, Citrobacter, and Morganella
B. Escherichia, Salmonella, Shigella, and Yersinia
An isolate of E. coli recovered from the stool of a patient with severe bloody diarrhea should be tested for which sugar before sending it to a reference laboratory for serotyping?
A. Sorbitol (fermentation)
B. Mannitol (oxidation)
C. Raffinose (fermentation)
D. Sucrose (fermentation)
A. Sorbitol (fermentation)
Care must be taken when identifying biochemical isolates of Shigella because serological cross reactions occur with:
A. Escherichia coli
B. Salmonella spp.
C. Pseudomonas spp.
D. Proteus spp.
A. Escherichia coli
Which species of Shigella is most commonly associated with diarrheal disease in the United States?
A. Shigella dysenteriae
B. Shigella flexneri
C. Shigella boydii
D. Shigella sonnei
D. Shigella sonnei
Which of the following tests best differentiates Shigella species from E. coli?
A. H2S, VP, citrate, and urease
B. Lactose, indole, ONPG, and motility
C. Hydrogen sulfide, MR, citrate, and urease
D. Gas, citrate, and VP
B. Lactose, indole, ONPG, and motility
Which genera of Enterobacteriaceae are usually nonmotile at 36°C?
A. Shigella, Klebsiella, and Yersinia
B. Escherichia, Edwardsiella, and Enterobacter
C. Proteus, Providencia, and Salmonella
D. Serratia, Morganella, and Hafnia
A. Shigella, Klebsiella, and Yersinia
Fever, abdominal cramping, watery stools, and fluid and electrolyte loss preceded by bloody stools 2 to 3 days before is characteristic of shigellosis but may also result from infection with:
A. Campylobacter spp.
B. Salmonella spp.
C. Proteus spp.
D. Yersinia spp.
A. Campylobacter spp.
Cold enrichment of feces (incubation at 4°C) in phosphate-buffered saline prior to subculture onto enteric media enhances the recovery of:
A. Enterotoxigenic Escherichia coli
B. Salmonella paratyphi
C. Hafnia alvei
D. Yersinia enterocolitica
D. Yersinia enterocolitica
Which group of tests, along with colonial morphology on primary media, aids most in the rapid identification of Enterobacteriaceae?
A. MR and VP, urease, and blood agar plate
B. Phenylalanine deaminase, urease, and CDC agar plate
C. Bacitracin, β-lactamase, and MacConkey agar plate
D. Indole, oxidase, MacConkey, and blood agar plates
D. Indole, oxidase, MacConkey, and blood agar plates