AAB MT MICROBIOLOGY EXAM ACTUAL

AAB MT MICROBIOLOGY EXAM (ACTUAL / )

QUESTIONS AND VERIFIED CORRECT ANSWERS

Nonfermenters produce what reaction in triple sugar iron (TSI) agar? - ---Answers_----Alkaline slant, alkaline or neutral butt

Which of the following amino acids are used in the test for decarboxylase? - ---Answers_----lysine, arginine, and ornithine

How many tubes are required to perform the decarboxylase test? - ---Answers_----4 tubes are needed; one for each substrate plus one control tube

Which of the following is an enzyme that removes the amino group from the amino acid? - ---Answers_----Deaminase

What is the decarboxylase test? - ---Answers_----The decarboxylase test is useful for differentiating the Enterobacteriaceae. Bromcresol phosphate is purple at pH 6.8 and above. It is yellow at pH below 5.2.

Organisms that produce urease do what to the medium? - --- Answers_----Hydrolyze urea to ammonia

Hydrogen sulfide production, other than in triple sugar iron agar, requires a source of metal and what other component in 1 / 3

the test medium? - ---Answers_----An organic source of sulfur

All of the following organisms are nonmotile at 37 degrees C except which one? - ---Answers_----Proteus vulgaris

Gelatinase breaks down gelatin into which end products? - --- Answers_----Amino acids

What indicates a positive DNase result after 0.1 HCl is added to the plate? - ---Answers_----Clearing around the colony

What is the DNase test? - ---Answers_----DNase agar is a differential medium that tests the ability of an organism to produce an exoenzyme, called deoxyribonuclease or DNase, that hydrolyzes DNA. DNase agar contains nutrients for the bacteria, DNA, and methyl green as an indicator.

If the negative nitrate reduction test does not change color after the powdered zinc is added, how is it reported? - --- Answers_----Positive -- No color after powdered zinc Negative -- Red after powdered zinc

What is the purpose of the ONPG test? - ---Answers_---- Detects slow lactose fermenters

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What is the ONPG test? - ---Answers_----Ortho-Nitrophenyl- β-galactoside (ONPG) is a colorimetric and spectrophotometric substrate for detection of beta- galactosidase activity. β-galactosidase is required for lactose utilization. Negative = no color; positive = yellow.

Salmonella, Shigella, and Eschericia coli have what in common? - ---Answers_----All are members of Enterobacteriaceae

A GNR isolated from a urine culture has the following

reactions:

IMViC ++-- Motility Positive Urease Negative - ---Answers_----Escherichia coli

A GNR isolated from a stool culture has the following

reactions:

Urease Negative Phenylalanine deaminase Negative Lysine decarboxylase Negative Motility Negative Citrate Negative - ---Answers_----Shigella dysenteriae

A mucoid lactose fermenter was isolated from a sputum

specimen on MacConkey agar with these reactions:

Motility Negative

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