BOC Microbiology Revision Exam
Questions With Guaranteed Pass
Solutions.
Biochemically, the Enterobacteriaceae are gram negative rods that: - Answer Ferment glucose, reduce
nitrate to nitrite, and are oxidase negative.
THe ortho-nitrophenyl-Beta-galactopyranoside (ONPG) test is most useful when differentiating: - Answer
Shigella spp. from some strains of Escherichia coli
The Voges-Proskauer (VP) test detects which end product of glucose fermentation? - Answer Acetoin
At which pH does the methyl red(MR) test become positive? - Answer pH of 4.5
A positive Simmons citrate test is seen as a: - Answer 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. - Answer Ammonium carbonate
Which reagent is added to detect the production of indole? - Answer p-Dimethylaminobenzaldehyde
Decarboxylation of the amino acids lysine, ornithine, and arginine results in the formation of: - Answer
Amines
Lysine iron agar (LIA) showing a purple slant and blackened butt indicates: - Answer Salmonella spp.
, Putrescine is an alkaline amine product which bacterial enzyme? - Answer Ornithine decarboxylase
Which genera are positive for phenylalanine deaminase?
----Enterobacter, Escherichia, and Salmonella
----Morganella, Providencia, and Proteus
----Klebsiella and Enterobacter
----Proteus, Escherichia, and Shigella - Answer Morganella, Providencia and Proteus
Kligler iron agar (KIA) differs from triple-sugar iron agar (TSI) in the: - Answer The use of sucrose in the
medium
The malonate test is most useful in defferentiating which members of the Enterobacteriaceae? - Answer
Salmonella subgroups 2, and 3 (the former Arizona)
Which genera of the Enterobacteriaceae are known to cause diarrhea and are considered enteric
pathogens? - Answer 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? - Answer Sorbitol
(fermentation)
Care must be taken when identifying biochemical isolates of Shigella because serological cross reactions
occur with: - Answer E. coli
Which species of Shigella is most commonly associated with diarrheal disease in the united states? -
Answer S. sonnei
Which of the following tests best differentiates Shigella species from E. coli? - Answer Lactose, indole,
ONPG, and motility (Shigella is negative for all)
Which genera of Enterobacteriaceae ae usually nonmotile at 36C? - Answer Shigella, Klebsiella, and
Yersinia
Questions With Guaranteed Pass
Solutions.
Biochemically, the Enterobacteriaceae are gram negative rods that: - Answer Ferment glucose, reduce
nitrate to nitrite, and are oxidase negative.
THe ortho-nitrophenyl-Beta-galactopyranoside (ONPG) test is most useful when differentiating: - Answer
Shigella spp. from some strains of Escherichia coli
The Voges-Proskauer (VP) test detects which end product of glucose fermentation? - Answer Acetoin
At which pH does the methyl red(MR) test become positive? - Answer pH of 4.5
A positive Simmons citrate test is seen as a: - Answer 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. - Answer Ammonium carbonate
Which reagent is added to detect the production of indole? - Answer p-Dimethylaminobenzaldehyde
Decarboxylation of the amino acids lysine, ornithine, and arginine results in the formation of: - Answer
Amines
Lysine iron agar (LIA) showing a purple slant and blackened butt indicates: - Answer Salmonella spp.
, Putrescine is an alkaline amine product which bacterial enzyme? - Answer Ornithine decarboxylase
Which genera are positive for phenylalanine deaminase?
----Enterobacter, Escherichia, and Salmonella
----Morganella, Providencia, and Proteus
----Klebsiella and Enterobacter
----Proteus, Escherichia, and Shigella - Answer Morganella, Providencia and Proteus
Kligler iron agar (KIA) differs from triple-sugar iron agar (TSI) in the: - Answer The use of sucrose in the
medium
The malonate test is most useful in defferentiating which members of the Enterobacteriaceae? - Answer
Salmonella subgroups 2, and 3 (the former Arizona)
Which genera of the Enterobacteriaceae are known to cause diarrhea and are considered enteric
pathogens? - Answer 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? - Answer Sorbitol
(fermentation)
Care must be taken when identifying biochemical isolates of Shigella because serological cross reactions
occur with: - Answer E. coli
Which species of Shigella is most commonly associated with diarrheal disease in the united states? -
Answer S. sonnei
Which of the following tests best differentiates Shigella species from E. coli? - Answer Lactose, indole,
ONPG, and motility (Shigella is negative for all)
Which genera of Enterobacteriaceae ae usually nonmotile at 36C? - Answer Shigella, Klebsiella, and
Yersinia
