Question 1

Chromogenic cephalosporins are used to test for:

Accepted Answer

A)  action of beta-lactamase inhibitors. 
B)  intrinsic resistance to beta-lactam drugs by decreased intracellular uptake of the drug. 
C)  production of beta-lactamase by the infecting organism. 
D)  intrinsic resistance to beta-lactam drugs by altered antibiotic targets. 
A)  action of beta-lactamase inhibitors. 
B)  intrinsic resistance to beta-lactam drugs by decreased intracellular uptake of the drug. 
C)  production of beta-lactamase by the infecting organism. 
D)  intrinsic resistance to beta-lactam drugs by altered antibiotic targets. C

Question 2

An important requirement for appropriate inoculum preparation in susceptibility testing includes the use of a(n):

Accepted Answer

A)  pure culture. 
B)  inoculum that matches the severity of the infection. 
C)  single isolated colony. 
D)  variety of colony types. 
A)  pure culture. 
B)  inoculum that matches the severity of the infection. 
C)  single isolated colony. 
D)  variety of colony types. A

Question 3

Growth on the oxacillin agar screen means that a patient should be treated with which antibiotic?

Accepted Answer

A)  Oxacillin 
B)  Methicillin 
C)  Vancomycin 
D)  Cephalosporin 
A)  Oxacillin 
B)  Methicillin 
C)  Vancomycin 
D)  Cephalosporin C

Question 4

Bactericidal tests should be performed:

Accepted Answer

A)  for every clinically significant organism isolated from a clinical specimen. 
B)  to evaluate antimicrobial agents usually considered to be bacteriostatic. 
C)  for severe and life-threatening infections. 
D)  on all gram-positive and gram-negative organisms, whether or not they are clinically significant. 
A)  for every clinically significant organism isolated from a clinical specimen. 
B)  to evaluate antimicrobial agents usually considered to be bacteriostatic. 
C)  for severe and life-threatening infections. 
D)  on all gram-positive and gram-negative organisms, whether or not they are clinically significant.

Question 5

A bacterial suspension of 1.5 x 10⁸ colony-forming units (CFUs)/mL is comparable with which standard inoculum?

Accepted Answer

A)  0.5 
B)  1.0 
C)  1.5 
D)  2.0 
A)  0.5 
B)  1.0 
C)  1.5 
D)  2.0

Question 6

In the disk diffusion method of antimicrobial susceptibility testing, what is the standard agar base medium used for testing most bacterial organisms?

Accepted Answer

A)  5% blood agar 
B)  Mueller-Hinton agar 
C)  Mueller-Hinton broth 
D)  Brain-heart infusion broth 
A)  5% blood agar 
B)  Mueller-Hinton agar 
C)  Mueller-Hinton broth 
D)  Brain-heart infusion broth

Question 7

Detection of the haze produced by some resistant staphylococci and enterococci against methicillin and vancomycin can best be accomplished by:

Accepted Answer

A)  using reflected light. 
B)  using transmitted light. 
C)  placing the medium under the light, rather than in front of it. 
D)  microscopy. 
A)  using reflected light. 
B)  using transmitted light. 
C)  placing the medium under the light, rather than in front of it. 
D)  microscopy.

Question 8

The minimum inhibitory concentration (MIC)result recorded in antimicrobial testing can be defined as the:

Accepted Answer

A)  maximum concentration of antimicrobial agent that should be used for optimal therapy. 
B)  minimum concentration of antimicrobial agent that should be used for optimal therapy. 
C)  lowest antimicrobial agent concentration that completely inhibits visible bacterial growth. 
D)  highest antimicrobial agent concentration that completely inhibits visible bacterial growth. 
A)  maximum concentration of antimicrobial agent that should be used for optimal therapy. 
B)  minimum concentration of antimicrobial agent that should be used for optimal therapy. 
C)  lowest antimicrobial agent concentration that completely inhibits visible bacterial growth. 
D)  highest antimicrobial agent concentration that completely inhibits visible bacterial growth.

Question 9

Staphylococcal resistance to oxacillin is used to determine and report resistance to:

Accepted Answer

A)  vancomycin. 
B)  aminoglycoside. 
C)  cephalosporin. 
D)  amikacin. 
A)  vancomycin. 
B)  aminoglycoside. 
C)  cephalosporin. 
D)  amikacin.

Question 10

The serum bactericidal test (SBT)involves:

Accepted Answer

A)  subculturing the clear tubes of a completed broth dilution test. 
B)  99.9% reduction in CFUs/mL, compared with the organism concentration in the original inoculum. 
C)  using patient serum to detect bacteriostatic and bactericidal activity and the antibacterial impact of factors other than the antibiotics. 
D)  microscopically interpreting results using microtiter plates. 
A)  subculturing the clear tubes of a completed broth dilution test. 
B)  99.9% reduction in CFUs/mL, compared with the organism concentration in the original inoculum. 
C)  using patient serum to detect bacteriostatic and bactericidal activity and the antibacterial impact of factors other than the antibiotics. 
D)  microscopically interpreting results using microtiter plates.

Question 11

The antibiotic nitrofurantoin is effective against both gram-positive and gram-negative bacteria.This antibiotic is effective against which type of specimen?

Accepted Answer

A)  Blood 
B)  Cerebrospinal fluid (CSF) 
C)  Urine 
D)  Sputum 
A)  Blood 
B)  Cerebrospinal fluid (CSF) 
C)  Urine 
D)  Sputum

Question 12

The minimal bactericidal concentration (MBC)test involves:

Accepted Answer

A)  testing the organism against gram-positive antibiotics. 
B)  testing the organism against gram-negative antibiotics. 
C)  99.9% reduction in CFUs/mL, compared with the organism concentration in the original inoculum. 
D)  observing the first tube where growth is inhibited. 
A)  testing the organism against gram-positive antibiotics. 
B)  testing the organism against gram-negative antibiotics. 
C)  99.9% reduction in CFUs/mL, compared with the organism concentration in the original inoculum. 
D)  observing the first tube where growth is inhibited.

Question 13

The concentrations in a broth dilution test that separate the categories of susceptible, intermediate, and resistant are called:

Accepted Answer

A)  MICs. 
B)  tolerance limits. 
C)  breakpoints. 
D)  border concentrations. 
A)  MICs. 
B)  tolerance limits. 
C)  breakpoints. 
D)  border concentrations.

Question 14

Up-to-date tables that list potential antimicrobial agents to include in batteries for testing against particular organisms or organism groups are published by the:

Accepted Answer

A)  Centers for Disease Control and Prevention (CD
C) . 
B)  National Committee for Clinical Laboratory Standards (NCCLS). 
C)  Manual of Standard Operating Procedures (MSOP). 
D)  Clinical and Laboratory Standards Institute (CLSI). 
A)  Centers for Disease Control and Prevention (CD
C) . 
B)  National Committee for Clinical Laboratory Standards (NCCLS). 
C)  Manual of Standard Operating Procedures (MSOP). 
D)  Clinical and Laboratory Standards Institute (CLSI).

Question 15

Enterococcal high-level gentamicin resistance predicts resistance to:

Accepted Answer

A)  vancomycin. 
B)  aminoglycoside. 
C)  cephalosporin. 
D)  amikacin. 
A)  vancomycin. 
B)  aminoglycoside. 
C)  cephalosporin. 
D)  amikacin.

Question 16

Enterococcal resistance to ampicillin predicts resistance to:

Accepted Answer

A)  vancomycin. 
B)  aminoglycoside. 
C)  cephalosporin. 
D)  amikacin. 
A)  vancomycin. 
B)  aminoglycoside. 
C)  cephalosporin. 
D)  amikacin.

Question 17

In the microdilution broth dilution method, the interpretive criteria for the susceptible, intermediate, or resistant categories are based on the:

Accepted Answer

A)  amount of turbidity in the test well. 
B)  correlations of the MIC with serum achievable levels for the antimicrobial agent, particular resistance mechanisms, and successful therapeutic outcomes. 
C)  size of the zone of inhibition. 
D)  reciprocal value of the MIC. 
A)  amount of turbidity in the test well. 
B)  correlations of the MIC with serum achievable levels for the antimicrobial agent, particular resistance mechanisms, and successful therapeutic outcomes. 
C)  size of the zone of inhibition. 
D)  reciprocal value of the MIC.

Question 18

Daptomycin, whose mode of action is to inhibit cell membrane function, is ineffective against which organism?

Accepted Answer

A)  Staphylococcus aureus 
B)  Enterococcus 
C)  Escherichia coli 
D)  Streptococcus spp. 
A)  Staphylococcus aureus 
B)  Enterococcus 
C)  Escherichia coli 
D)  Streptococcus spp.

Question 19

As a result of the organism going through several doubling generations of growth before inhibition, a haze of bacterial growth occurs on the agar around the disk.This phenomenon, which should be ignored, can be observed when testing which class of antibiotics?

Accepted Answer

A)  Aminoglycosides 
B)  Sulfonamides 
C)  Penicillins 
D)  Cephalosporins 
A)  Aminoglycosides 
B)  Sulfonamides 
C)  Penicillins 
D)  Cephalosporins

Question 20

The primary goal of antimicrobial susceptibility testing is to:

Accepted Answer

A)  determine whether the pathogen is capable of expressing resistance to the potential choices of antimicrobial agents. 
B)  determine the extent of an organism's intrinsic resistance. 
C)  determine in vivo whether the administered antibiotic is killing the pathogen. 
D)  identify toxins associated with bacterial pathogens. 
A)  determine whether the pathogen is capable of expressing resistance to the potential choices of antimicrobial agents. 
B)  determine the extent of an organism's intrinsic resistance. 
C)  determine in vivo whether the administered antibiotic is killing the pathogen. 
D)  identify toxins associated with bacterial pathogens.

Exam 12: Laboratory Methods and Strategies for Antimicrobial Susceptibility Testing

Chromogenic cephalosporins are used to test for:

An important requirement for appropriate inoculum preparation in susceptibility testing includes the use of a(n):

Growth on the oxacillin agar screen means that a patient should be treated with which antibiotic?

Bactericidal tests should be performed:

A bacterial suspension of 1.5 x 10⁸ colony-forming units (CFUs)/mL is comparable with which standard inoculum?

In the disk diffusion method of antimicrobial susceptibility testing, what is the standard agar base medium used for testing most bacterial organisms?

Detection of the haze produced by some resistant staphylococci and enterococci against methicillin and vancomycin can best be accomplished by:

The minimum inhibitory concentration (MIC)result recorded in antimicrobial testing can be defined as the:

Staphylococcal resistance to oxacillin is used to determine and report resistance to:

The serum bactericidal test (SBT)involves:

The antibiotic nitrofurantoin is effective against both gram-positive and gram-negative bacteria.This antibiotic is effective against which type of specimen?

The minimal bactericidal concentration (MBC)test involves:

The concentrations in a broth dilution test that separate the categories of susceptible, intermediate, and resistant are called:

Up-to-date tables that list potential antimicrobial agents to include in batteries for testing against particular organisms or organism groups are published by the:

Enterococcal high-level gentamicin resistance predicts resistance to:

Enterococcal resistance to ampicillin predicts resistance to:

In the microdilution broth dilution method, the interpretive criteria for the susceptible, intermediate, or resistant categories are based on the:

Daptomycin, whose mode of action is to inhibit cell membrane function, is ineffective against which organism?

As a result of the organism going through several doubling generations of growth before inhibition, a haze of bacterial growth occurs on the agar around the disk.This phenomenon, which should be ignored, can be observed when testing which class of antibiotics?

The primary goal of antimicrobial susceptibility testing is to:

Microbial Taxonomy

Bacterial Genetics, Metabolism, and Structure

Host-Microorganism Interactions

Laboratory Safety

Specimen Management

Role of Microscopy

Traditional Cultivation and Identification

Nucleic Acid-Based Analytic Methods for Microbial Identification and Characterization

Immunochemical Methods Used for Organism Detection

Serologic Diagnosis of Infectious Diseases

Principles of Antimicrobial Action and Resistance

Staphylococcus Micrococcus and Similar Organisms

Streptococcus Enterococcus and Similar Organisms

Bacillus and Similar Organisms

Listeria Corynebacterium and Similar Organisms

Erysipelothrix Lactobacillus and Similar Organisms

Nocardia Streptomyces Rhodococcus and Similar Organisms

Enterobacteriaceae

Acinetobacter, Stenotrophomonas, and Other Organisms

Pseudomonas, Burkholderia, and Similar Organisms

Rhizobium, Ochrobactrum, and Similar Organisms

Chryseobacterium, Sphingobacterium, and Similar Organisms

Alcaligenes, Bordetella Nonpertussis, Comamonas, and Similar Organisms

Vibrio, Aeromonas, Chromobacterium, and Related Organisms

Sphingomonas Paucimobilis and Similar Organisms

Moraxella and Related Organisms

Eikenella and Similar Organisms

Pasteurella and Similar Organisms

Actinobacillus, Aggregatibacter, Kingella, Cardiobacterium, Capnocytophaga, and Similar Organisms

Haemophilus

Bartonella and Afipia

Campylobacter, Arcobacter, and Helicobacter

Legionella

Brucella

Bordetella Pertussis, Bordetella Parapertussis, and Related Species

Francisella

Streptobacillus Moniliformis and Spirillum Minus

Neisseria and Moraxella Catarrhalis

Overview and General Considerations

Overview of Anaerobic Organisms

Mycobacteria

Obligate Intracellular and Non-culturable Bacterial Agents

Cell Walldeficient Bacteria: Mycoplasma and Ureaplasma

The Spirochetes

Laboratory Methods for Diagnosis of Parasitic Infections: Overview

Intestinal Protozoa

Blood and Tissue Protozoa

Other Protozoa

Intestinal Nematodes Roundworms

Tissue Nematodes Roundworms

Blood and Tissue Filarialnematodes

Intestinal Cestodes

Tissue Cestodes

Intestinal Trematodes

Liver and Lung Trematodes

Blood Trematodes

Overview of Fungal Identification Methods and Strategies

Hyaline Molds, Mucorales Zygomycetes, Dermatophytes, and Opportunitistic and Systemic Mycoses

Dematiaceous Melanizedmolds