Question 1

What type of medium is used in the motility test?

Accepted Answer

A)  Semi-solid 
B)  Cornmeal 
C)  Sabouraud dextrose 
D)  Peptone gel 
A)  Semi-solid 
B)  Cornmeal 
C)  Sabouraud dextrose 
D)  Peptone gel A

Question 2

What are the sugars present in triple sugar iron (TSI)?

Accepted Answer

A)  Sucrose, glucose, lactose 
B)  Mannitol, lactose, arabinose 
C)  Sucrose, glucose, rhamnose 
D)  Lactose, sucrose, raffinose 
A)  Sucrose, glucose, lactose 
B)  Mannitol, lactose, arabinose 
C)  Sucrose, glucose, rhamnose 
D)  Lactose, sucrose, raffinose A

Question 3

This reagent is used to demonstrate a positive phenylalanine deaminase test.

Accepted Answer

A)  10% ferric chloride 
B)  Methyl red 
C)  $\alpha$-Naphthol 
D)  40% sodium hydroxide 
A)  10% ferric chloride 
B)  Methyl red 
C)  $\alpha$-Naphthol 
D)  40% sodium hydroxide A

Question 4

Name the two reagents that are needed to visualize nitrite in the nitrate reduction test.

Accepted Answer

A)  Sulfanilic acid and 40% sodium hydroxide 
B)  Sulfuric acid and $\alpha$-naphthol 
C)  N,N-dimethyl-$\alpha$-naphthylamine and sulfanilic acid 
D)  N,N-dimethyl-$\alpha$-naphthylamine and sulfuric acid 
A)  Sulfanilic acid and 40% sodium hydroxide 
B)  Sulfuric acid and $\alpha$-naphthol 
C)  N,N-dimethyl-$\alpha$-naphthylamine and sulfanilic acid 
D)  N,N-dimethyl-$\alpha$-naphthylamine and sulfuric acid

Question 5

Bacteria demonstrating weak decarboxylase activity

Accepted Answer

A)  will have a false-negative test. 
B)  may take up to 4 days to be positive. 
C)  require extra reagents to show the positive reaction. 
D)  will have a false-positive test. 
A)  will have a false-negative test. 
B)  may take up to 4 days to be positive. 
C)  require extra reagents to show the positive reaction. 
D)  will have a false-positive test.

Question 6

The principle of the citrate test includes all the following, except:

Accepted Answer

A)  Bacteria able to use citrate will use the ammonium salts releasing ammonia. 
B)  The alkaline pH that results from use of the ammonium salts changes the pH indicator. 
C)  The pH indicator changes from red to bright yellow. 
D)  The pH indicator changes from green to blue. 
A)  Bacteria able to use citrate will use the ammonium salts releasing ammonia. 
B)  The alkaline pH that results from use of the ammonium salts changes the pH indicator. 
C)  The pH indicator changes from red to bright yellow. 
D)  The pH indicator changes from green to blue.

Question 7

What amino acid is the substrate in indole test broth?

Accepted Answer

A)  Ornithine 
B)  Arginine 
C)  Tryptophan 
D)  Leucine 
A)  Ornithine 
B)  Arginine 
C)  Tryptophan 
D)  Leucine

Question 8

Why does the Moeller decarboxylase base medium contain glucose if it is testing the decarboxylation of amino acids?

Accepted Answer

A)  The decarboxylation of the amino acids takes place during the glucose metabolic pathway. Once glucose is broken down into pyruvic acid, then the amino acid is modified. 
B)  To get the energy needed to take the carboxyl group off the amino acid, the bacteria must have glucose. 
C)  When glucose is fermented, one of the by-products is acetoin. This acetoin is part of the mechanism that cleaves the carboxyl group from the specific amino acid. 
D)  Decarboxylases are inducible enzymes produced in an acid pH. 
A)  The decarboxylation of the amino acids takes place during the glucose metabolic pathway. Once glucose is broken down into pyruvic acid, then the amino acid is modified. 
B)  To get the energy needed to take the carboxyl group off the amino acid, the bacteria must have glucose. 
C)  When glucose is fermented, one of the by-products is acetoin. This acetoin is part of the mechanism that cleaves the carboxyl group from the specific amino acid. 
D)  Decarboxylases are inducible enzymes produced in an acid pH.

Question 9

This test is useful in the initial differentiation of Proteus, Morganella, and Providencia species from the rest of the Enterobacteriaceae.

Accepted Answer

A)  Oxidation-fermentation 
B)  Methyl red 
C)  Amino acid decarboxylase 
D)  Phenylalanine deaminase 
A)  Oxidation-fermentation 
B)  Methyl red 
C)  Amino acid decarboxylase 
D)  Phenylalanine deaminase

Question 10

The methyl red test detects metabolic by-products from what pathway?

Accepted Answer

A)  Mixed acid fermentation pathway 
B)  Butylene glycol pathway 
C)  Citrate pathway 
D)  Clark and Lubs pathway 
A)  Mixed acid fermentation pathway 
B)  Butylene glycol pathway 
C)  Citrate pathway 
D)  Clark and Lubs pathway

Question 11

What two reagents can be used to visualize indole in the broth?

Accepted Answer

A)  Indole and xylene 
B)  40% sodium hydroxide and α-naphthol 
C)  10% ferric chloride 
D)  Ehrlich's and Kovac's 
A)  Indole and xylene 
B)  40% sodium hydroxide and α-naphthol 
C)  10% ferric chloride 
D)  Ehrlich's and Kovac's

Question 12

This test determines if an organism is a delayed lactose fermenter.

Accepted Answer

A)  $\beta$-Galactosidase 
B)  Dihydroxylase 
C)  Nitrate 
D)  o-nitrophenyl-$\beta$-D-galactopyranoside (ONPG) test 
A)  $\beta$-Galactosidase 
B)  Dihydroxylase 
C)  Nitrate 
D)  o-nitrophenyl-$\beta$-D-galactopyranoside (ONPG) test

Question 13

What medium is used in the urease test?

Accepted Answer

A)  Christensen media 
B)  Loeffler's media 
C)  Moeller's oxidative broth 
D)  Kovac's reagent 
A)  Christensen media 
B)  Loeffler's media 
C)  Moeller's oxidative broth 
D)  Kovac's reagent

Question 14

A positive test for motility

Accepted Answer

A)  turns the motility media blue. 
B)  shows hazy appearance throughout or movement away from a stab. 
C)  appears as a scum on the top of the media. 
D)  will turn blue after the addition of the indicator bromothymol blue. 
A)  turns the motility media blue. 
B)  shows hazy appearance throughout or movement away from a stab. 
C)  appears as a scum on the top of the media. 
D)  will turn blue after the addition of the indicator bromothymol blue.

Question 15

What chemicals are added to TSI to detect the production of hydrogen sulfide gas?

Accepted Answer

A)  Phenol red and ferrous sulfate 
B)  Bromothymol blue and sodium thiosulfate 
C)  Ferrous sulfate and sodium thiosulfate 
D)  Copper sulfate and ferrous sulfate 
A)  Phenol red and ferrous sulfate 
B)  Bromothymol blue and sodium thiosulfate 
C)  Ferrous sulfate and sodium thiosulfate 
D)  Copper sulfate and ferrous sulfate

Question 16

When performing the O/F test, one tube is covered with mineral oil and one tube is left uncovered. Why is one tube covered with mineral oil?

Accepted Answer

A)  To create an anaerobic (fermentative) environment 
B)  To create an aerobic (oxidative) environment 
C)  To create a reductive environment 
D)  To create an asaccharolytic environment 
A)  To create an anaerobic (fermentative) environment 
B)  To create an aerobic (oxidative) environment 
C)  To create a reductive environment 
D)  To create an asaccharolytic environment

Question 17

The two reagents used in the Voges-Proskauer test are

Accepted Answer

A)  methyl red and acetoin. 
B)  40% KOH and methyl red. 
C)  o-nitrophenol and $\alpha$-naphthol. 
D)  40% KOH and $\alpha$-naphthol. 
A)  methyl red and acetoin. 
B)  40% KOH and methyl red. 
C)  o-nitrophenol and $\alpha$-naphthol. 
D)  40% KOH and $\alpha$-naphthol.

Question 18

During this process, glucose enters the glycolysis pathway, resulting in the formation of pyruvic acid, which is further oxidized to other acids. What is this process called?

Accepted Answer

A)  Oxidation 
B)  Reduction 
C)  Fermentation 
D)  Synthesis 
A)  Oxidation 
B)  Reduction 
C)  Fermentation 
D)  Synthesis

Question 19

A technician is reading the biochemical tests for identifying a particular gram-negative rod. The organism has produced acid, indicated by a color change, in the closed tube only. This indicates that the organism is

Accepted Answer

A)  an oxidizer. 
B)  a fermenter. 
C)  both an oxidizer and a fermenter. 
D)  a reducer. 
A)  an oxidizer. 
B)  a fermenter. 
C)  both an oxidizer and a fermenter. 
D)  a reducer.

Question 20

This identification system for Enterobacteriaceae has a series of 20 cupules attached to a plastic strip. Inside the cupules are lyophilized pH-based substrates. What is the name of this system?

Accepted Answer

A)  ID Tri-Panel 
B)  API 20E 
C)  Microbact 
D)  Enterotube II 
A)  ID Tri-Panel 
B)  API 20E 
C)  Microbact 
D)  Enterotube II

Exam 9: Biochemical Identification of Gram-Negative Bacteria

What type of medium is used in the motility test?

What are the sugars present in triple sugar iron (TSI)?

This reagent is used to demonstrate a positive phenylalanine deaminase test.

Name the two reagents that are needed to visualize nitrite in the nitrate reduction test.

Bacteria demonstrating weak decarboxylase activity

The principle of the citrate test includes all the following, except:

What amino acid is the substrate in indole test broth?

Why does the Moeller decarboxylase base medium contain glucose if it is testing the decarboxylation of amino acids?

This test is useful in the initial differentiation of Proteus, Morganella, and Providencia species from the rest of the Enterobacteriaceae.

The methyl red test detects metabolic by-products from what pathway?

What two reagents can be used to visualize indole in the broth?

This test determines if an organism is a delayed lactose fermenter.

What medium is used in the urease test?

A positive test for motility

What chemicals are added to TSI to detect the production of hydrogen sulfide gas?

When performing the O/F test, one tube is covered with mineral oil and one tube is left uncovered. Why is one tube covered with mineral oil?

The two reagents used in the Voges-Proskauer test are

During this process, glucose enters the glycolysis pathway, resulting in the formation of pyruvic acid, which is further oxidized to other acids. What is this process called?

A technician is reading the biochemical tests for identifying a particular gram-negative rod. The organism has produced acid, indicated by a color change, in the closed tube only. This indicates that the organism is

This identification system for Enterobacteriaceae has a series of 20 cupules attached to a plastic strip. Inside the cupules are lyophilized pH-based substrates. What is the name of this system?

Bacterial Cell Structure, Physiology, Metabolism, and Genetics

Hostparasite Interaction

The Laboratory Role in Infection Control

Control of Microorganisms

Performance Improvement in the Microbiology Laboratory

Specimen Collection and Processing

Microscopic Examination of Materials From Infected Sites

Use of Colony Morphology for the Presumptive Identification of Microorganisms

Immunodiagnosis of Infectious Diseases

Applications of Molecular Diagnostics

Antimicrobial Agent Mechanisms of Action and Resistance Mechanisms

Antimicrobial Susceptibility Testing

Staphylococci

Streptococcus, Enterococcus, and Other Catalase-Negative, Gram-Positive Cocci

Aerobic Gram-Positive Bacilli

Neisseria Species and Moraxella Catarrhalis

Haemophilus, Hacek, Legionella, and Other Fastidious Gram-Negative Bacilli

Enterobacteriaceae

Vibrio, Aeromonas, and Campylobacter Species

Nonfermenting and Miscellaneous Gram-Negative Bacilli

Anaerobes of Clinical Importance

The Spirochetes

Chlamydia, Rickettsia, and Similar Organisms

Mycoplasma and Ureaplasma

Mycobacterium Tuberculosis and Nontuberculous Mycobacteria

Medically Significant Fungi

Diagnostic Parasitology

Clinical Virology

Agents of Bioterror and Forensic Microbiology

Biofilms: Architects of Disease

Upper and Lower Respiratory Tract Infections

Skin and Soft Tissue Infections

Gastrointestinal Infections and Food Poisoning

Infections of the Central Nervous System

Bacteremia and Sepsis

Urinary Tract Infections

Genital Infections and Sexually Transmitted Infections

Infections in Special Populations

Zoonotic Diseases

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