Question 1

Important factors that must be considered when determining whether antimicrobial susceptibility testing is warranted include

Accepted Answer

A)  the body site from which the organism was isolated. 
B)  the presence of other bacteria and the quality of the specimen from which the organism was grown. 
C)  the host's status. 
D)  All the above 
A)  the body site from which the organism was isolated. 
B)  the presence of other bacteria and the quality of the specimen from which the organism was grown. 
C)  the host's status. 
D)  All the above

Question 2

Oxacillin-resistant Staphylococcus aureus is called

Accepted Answer

A)  methicillin-resistant S. aureus (MRS
A) . 
B)  oxacillin-resistant S. aureus. 
C)  penicillin-resistant S. aureus. 
D)  penicillinase-resistant S. aureus. 
A)  methicillin-resistant S. aureus (MRS
A) . 
B)  oxacillin-resistant S. aureus. 
C)  penicillin-resistant S. aureus. 
D)  penicillinase-resistant S. aureus.

Question 3

In this type of antimicrobial susceptibility test, a McFarland 0.5 standardized suspension of bacteria is swabbed over the surface of a Mueller-Hinton agar plate, and paper disks containing single concentrations of each antimicrobial agent are placed onto the inoculated surface. What is the name of this test?

Accepted Answer

A)  Kirby-Bauer 
B)  MIC 
C)  Breakpoint 
D)  Agar dilution 
A)  Kirby-Bauer 
B)  MIC 
C)  Breakpoint 
D)  Agar dilution

Question 4

How are antibiotics chosen for inclusion into laboratory antimicrobial testing protocols?

Accepted Answer

A)  There are no set standards, because physicians demand which drugs they want tested for particular bugs each time an antimicrobial susceptibility test is performed. 
B)  The Clinical and Laboratory Standards Institute (CLSI) recommends the drugs that should be tested and reported for each type of specimen. 
C)  The institutional pharmacy and therapeutics committee sets the list of drugs that are used in their facility 
D)  Both B and C. 
A)  There are no set standards, because physicians demand which drugs they want tested for particular bugs each time an antimicrobial susceptibility test is performed. 
B)  The Clinical and Laboratory Standards Institute (CLSI) recommends the drugs that should be tested and reported for each type of specimen. 
C)  The institutional pharmacy and therapeutics committee sets the list of drugs that are used in their facility 
D)  Both B and C.

Question 5

Quality control of antimicrobial susceptibility tests involves

Accepted Answer

A)  performing antimicrobial susceptibility tests on organisms using the CLSI charts to interpret the results. 
B)  using organisms grown from patient cultures to test the reactivity of the antimicrobial drugs. 
C)  testing standard reference strains that have defined antimicrobial susceptibility (or resistance) to the drugs tested. 
D)  None of the above 
A)  performing antimicrobial susceptibility tests on organisms using the CLSI charts to interpret the results. 
B)  using organisms grown from patient cultures to test the reactivity of the antimicrobial drugs. 
C)  testing standard reference strains that have defined antimicrobial susceptibility (or resistance) to the drugs tested. 
D)  None of the above

Question 6

Guidance for the development of a selective-reporting or cascade-reporting protocol for antibiotics is available from the

Accepted Answer

A)  Centers for Disease Control and Prevention (CD
C) . 
B)  Clinical Laboratory and Standards Institute (CLSI). 
C)  United States Army Medical Research Institute (USAMRII
D) . 
D)  Food and Drug Administration (FD
A) . 
A)  Centers for Disease Control and Prevention (CD
C) . 
B)  Clinical Laboratory and Standards Institute (CLSI). 
C)  United States Army Medical Research Institute (USAMRII
D) . 
D)  Food and Drug Administration (FD
A) .

Question 7

On what media is Kirby-Bauer testing performed for Neisseria gonorrhoeae?

Accepted Answer

A)  GC agar base supplemented with various nutrients 
B)  Mueller-Hinton agar supplemented with vancomycin 
C)  Mueller-Hinton agar supplemented with X and V factors 
D)  Mueller-Hinton agar supplemented with biotin, and X and V factors 
A)  GC agar base supplemented with various nutrients 
B)  Mueller-Hinton agar supplemented with vancomycin 
C)  Mueller-Hinton agar supplemented with X and V factors 
D)  Mueller-Hinton agar supplemented with biotin, and X and V factors

Question 8

Goals of combination antimicrobial therapy include all the following, except

Accepted Answer

A)  obtain broad-spectrum coverage. 
B)  enhance antibacterial activity through synergistic interactions. 
C)  minimize resistance development. 
D)  ensure that at least one antimicrobial will obtain the MBC at the infection site. 
A)  obtain broad-spectrum coverage. 
B)  enhance antibacterial activity through synergistic interactions. 
C)  minimize resistance development. 
D)  ensure that at least one antimicrobial will obtain the MBC at the infection site.

Question 9

Agar dilution and disk diffusion tests for Streptococcus pneumoniae and Streptococcus spp. use

Accepted Answer

A)  Mueller-Hinton agar supplemented with X and V factors. 
B)  Columbia base supplemented with 5% sheep blood. 
C)  trypticase soy agar base supplemented with 5% lysed horse blood. 
D)  Mueller-Hinton agar supplemented with 5% sheep blood. 
A)  Mueller-Hinton agar supplemented with X and V factors. 
B)  Columbia base supplemented with 5% sheep blood. 
C)  trypticase soy agar base supplemented with 5% lysed horse blood. 
D)  Mueller-Hinton agar supplemented with 5% sheep blood.

Question 10

When would it be appropriate for an institution to routinely test group C agents?

Accepted Answer

A)  For urinary tract infections 
B)  If a particular institution routinely encounters large numbers of isolates resistant to group A and group B agents 
C)  For blood cultures 
D)  If a particular institution routinely encounters large numbers of isolates susceptible to group A and group B agents 
A)  For urinary tract infections 
B)  If a particular institution routinely encounters large numbers of isolates resistant to group A and group B agents 
C)  For blood cultures 
D)  If a particular institution routinely encounters large numbers of isolates susceptible to group A and group B agents

Question 11

What is the most widely used supplementary quality control measure for antimicrobial susceptibility testing?

Accepted Answer

A)  $\beta$-Lactamase testing 
B)  Use of antibiograms to verify results generated on patient isolates 
C)  Correlation of clinical outcomes with laboratory findings 
D)  None of the above 
A)  $\beta$-Lactamase testing 
B)  Use of antibiograms to verify results generated on patient isolates 
C)  Correlation of clinical outcomes with laboratory findings 
D)  None of the above

Question 12

Two antibiotics are contraindicated in pediatric patients. They are

Accepted Answer

A)  erythromycin and augmentin. 
B)  cleocin and zithromax. 
C)  tetracycline and ceclor. 
D)  tetracycline and fluoroquinolones. 
A)  erythromycin and augmentin. 
B)  cleocin and zithromax. 
C)  tetracycline and ceclor. 
D)  tetracycline and fluoroquinolones.

Question 13

What is the principle of the most commonly used test to detect $\beta$-lactamase production?

Accepted Answer

A)  Chromogenic cephalosporin nitrocefin 
B)  Redox reaction 
C)  Hydrolysis of fluorogenic substrate 
D)  Reduction of acetoin 
A)  Chromogenic cephalosporin nitrocefin 
B)  Redox reaction 
C)  Hydrolysis of fluorogenic substrate 
D)  Reduction of acetoin

Question 14

Once zone measurements have been made, the millimeter reading for each antimicrobial agent is

Accepted Answer

A)  sent to the physician to determine the appropriateness of antibiotic therapy for his patient. 
B)  converted into MIC units. 
C)  interpreted as susceptible, intermediate, or resistant. 
D)  None of the above 
A)  sent to the physician to determine the appropriateness of antibiotic therapy for his patient. 
B)  converted into MIC units. 
C)  interpreted as susceptible, intermediate, or resistant. 
D)  None of the above

Question 15

A microbiology technologist is performing a $\beta$-lactamase test on a staphylococcus isolated from a hospitalized patient. The test was negative, so the technologist reported out in vitro antimicrobial susceptibility test results for $\beta$-lactam antibiotics. After 2 days, the patient was not improving and the physician changed the patient's antibiotic to an aminoglycoside. The patient showed improvement immediately. Why was the $\beta$-lactamase test on the staphylococci negative, when the organism produced $\beta$-lactamase?

Accepted Answer

A)  The test was a false negative-the organism really did produce $\beta$-lactamase, but it did not react with the test. 
B)  Staphylococci must be exposed to the $\beta$-lactam agent before it will produce a positive test result. 
C)  The test was a false positive-the organism reacted with the test, but it did not produce a $\beta$-lactamase. 
D)  The staphylococci on the plate were more than 24 hours old and false-negative test results can occur when an "old" organism is used. 
A)  The test was a false negative-the organism really did produce $\beta$-lactamase, but it did not react with the test. 
B)  Staphylococci must be exposed to the $\beta$-lactam agent before it will produce a positive test result. 
C)  The test was a false positive-the organism reacted with the test, but it did not produce a $\beta$-lactamase. 
D)  The staphylococci on the plate were more than 24 hours old and false-negative test results can occur when an "old" organism is used.

Question 16

What is the storage temperature for frozen panels?

Accepted Answer

A)  0° C 
B)  -20° X  to -70° C 
C)  -75° X to -100° C 
D)  273 K 
A)  0° C 
B)  -20° X  to -70° C 
C)  -75° X to -100° C 
D)  273 K

Question 17

Which enterococcus is/are the most common species demonstrating vancomycin resistance among clinical isolates?

Accepted Answer

A)  Enterococcus faecium 
B)  E. faecalis 
C)  Both A and B 
D)  Neither A nor B 
A)  Enterococcus faecium 
B)  E. faecalis 
C)  Both A and B 
D)  Neither A nor B

Question 18

Note that for some antimicrobial agents, different MIC interpretive criteria exist for

Accepted Answer

A)  organisms or organism groups. 
B)  anatomic sites. 
C)  age groups. 
D)  immune status. 
A)  organisms or organism groups. 
B)  anatomic sites. 
C)  age groups. 
D)  immune status.

Question 19

What is the most widely used method of inoculum standardization?

Accepted Answer

A)  McFarland turbidity standards 
B)  Remel inoculum standards 
C)  Becton-Dickson standards 
D)  Difco standards 
A)  McFarland turbidity standards 
B)  Remel inoculum standards 
C)  Becton-Dickson standards 
D)  Difco standards

Question 20

If the MIC or zone size is interpreted as susceptible using the latest CLSI tables

Accepted Answer

A)  the clinical interpretation of the result is that the patient's infecting organism should respond to therapy with that antimicrobial agent using the dosage normally recommended for that type of infection and that species. 
B)  the patient's infecting organism is unlikely to be inhibited by the usually achievable concentrations of the antimicrobial agent based on the dosages normally used with that drug. 
C)  the patient's infecting organism is likely to require the maximum amount of antimicrobial for which the clinical response is likely to be less than with a susceptible strain. 
D)  None of the above 
A)  the clinical interpretation of the result is that the patient's infecting organism should respond to therapy with that antimicrobial agent using the dosage normally recommended for that type of infection and that species. 
B)  the patient's infecting organism is unlikely to be inhibited by the usually achievable concentrations of the antimicrobial agent based on the dosages normally used with that drug. 
C)  the patient's infecting organism is likely to require the maximum amount of antimicrobial for which the clinical response is likely to be less than with a susceptible strain. 
D)  None of the above

Exam 13: Antimicrobial Susceptibility Testing

Important factors that must be considered when determining whether antimicrobial susceptibility testing is warranted include

Oxacillin-resistant Staphylococcus aureus is called

How are antibiotics chosen for inclusion into laboratory antimicrobial testing protocols?

Quality control of antimicrobial susceptibility tests involves

Guidance for the development of a selective-reporting or cascade-reporting protocol for antibiotics is available from the

On what media is Kirby-Bauer testing performed for Neisseria gonorrhoeae?

Goals of combination antimicrobial therapy include all the following, except

Agar dilution and disk diffusion tests for Streptococcus pneumoniae and Streptococcus spp. use

When would it be appropriate for an institution to routinely test group C agents?

What is the most widely used supplementary quality control measure for antimicrobial susceptibility testing?

Two antibiotics are contraindicated in pediatric patients. They are

What is the principle of the most commonly used test to detect β\betaβ -lactamase production?

Once zone measurements have been made, the millimeter reading for each antimicrobial agent is

What is the storage temperature for frozen panels?

Which enterococcus is/are the most common species demonstrating vancomycin resistance among clinical isolates?

Note that for some antimicrobial agents, different MIC interpretive criteria exist for

What is the most widely used method of inoculum standardization?

If the MIC or zone size is interpreted as susceptible using the latest CLSI tables

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

Biochemical Identification of Gram-Negative Bacteria

Immunodiagnosis of Infectious Diseases

Applications of Molecular Diagnostics

Antimicrobial Agent Mechanisms of Action and Resistance Mechanisms

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

Ocular Infections

Filters

What is the principle of the most commonly used test to detect $\beta$ -lactamase production?