BOC MICROBIOLOGY EXAM 4 WITH
COMPLETE QUESTIONS AND ANSWERS [
GRADED A+]
Biochemically, the Enterobacteriaceae are gram negative rods that: - ✔✔Ferment
glucose, reduce nitrate to nitrite, and are oxidase negative.
THe ortho-nitrophenyl-Beta-galactopyranoside (ONPG) test is most useful when
differentiating: - ✔✔Shigella spp. from some strains of Escherichia coli
The Voges-Proskauer (VP) test detects which end product of glucose
fermentation? - ✔✔Acetoin
©morren2024/2025.Year published 2024.
, At which pH does the methyl red(MR) test become positive? - ✔✔pH of 4.5
A positive Simmons citrate test is seen as a: - ✔✔Blue color in the medium after
24 hours of incubation at 35C
A leg wound culture from a hospitalized 70 year old diabetic man grew motile,
lactose-negatvie colonies on MacConkey agar. Given the following biochemical
reactions at 24 hours, what is the most probable organism:
---------------------------------------------------------------------
H2S neg, TSI neg, Indole neg, DNase pos, urease neg, VP pos, Citrate pos,
Phenylalanine deaminase neg, ornithing and lysine pos, gelatin hydrolysis pos,
arginine neg. - ✔✔Ammonium carbonate
Which reagent is added to detect the production of indole? - ✔✔p-
Dimethylaminobenzaldehyde
©morren2024/2025.Year published 2024.
COMPLETE QUESTIONS AND ANSWERS [
GRADED A+]
Biochemically, the Enterobacteriaceae are gram negative rods that: - ✔✔Ferment
glucose, reduce nitrate to nitrite, and are oxidase negative.
THe ortho-nitrophenyl-Beta-galactopyranoside (ONPG) test is most useful when
differentiating: - ✔✔Shigella spp. from some strains of Escherichia coli
The Voges-Proskauer (VP) test detects which end product of glucose
fermentation? - ✔✔Acetoin
©morren2024/2025.Year published 2024.
, At which pH does the methyl red(MR) test become positive? - ✔✔pH of 4.5
A positive Simmons citrate test is seen as a: - ✔✔Blue color in the medium after
24 hours of incubation at 35C
A leg wound culture from a hospitalized 70 year old diabetic man grew motile,
lactose-negatvie colonies on MacConkey agar. Given the following biochemical
reactions at 24 hours, what is the most probable organism:
---------------------------------------------------------------------
H2S neg, TSI neg, Indole neg, DNase pos, urease neg, VP pos, Citrate pos,
Phenylalanine deaminase neg, ornithing and lysine pos, gelatin hydrolysis pos,
arginine neg. - ✔✔Ammonium carbonate
Which reagent is added to detect the production of indole? - ✔✔p-
Dimethylaminobenzaldehyde
©morren2024/2025.Year published 2024.
