Question 1

When should antimicrobial susceptibility testing be performed on a bacterial isolate from a clinical specimen?

Accepted Answer

A)  When the isolate is determined to be a probable cause of the patient's infection 
B)  When the susceptibility of the isolate to particular antimicrobial agents cannot be reliably predicted 
C)  When the organism is part of the normal microbiota 
D)  Both A and B 
A)  When the isolate is determined to be a probable cause of the patient's infection 
B)  When the susceptibility of the isolate to particular antimicrobial agents cannot be reliably predicted 
C)  When the organism is part of the normal microbiota 
D)  Both A and B

Question 2

Therapy of disseminated meningococcal infections and various types of gonococcal (GC) infections are

Accepted Answer

A)  hard to treat and require special $\beta$-lactamase tests. 
B)  an important public health concern, so a full spectrum of antimicrobial susceptibility testing is always performed. 
C)  generally empiric based on recommendations of CDC. 
D)  None of the above 
A)  hard to treat and require special $\beta$-lactamase tests. 
B)  an important public health concern, so a full spectrum of antimicrobial susceptibility testing is always performed. 
C)  generally empiric based on recommendations of CDC. 
D)  None of the above

Question 3

A combination of antimicrobials is said to show synergism if

Accepted Answer

A)  its antibacterial activity is significantly greater than that of the single agents. 
B)  its antibacterial activity is significantly less than that of the single agents. 
C)  the antibacterial activity is sustained for a much prolonged time compared with the single agents. 
D)  the antibacterial activity is sustained for a much shorter time compared with the single agents. 
A)  its antibacterial activity is significantly greater than that of the single agents. 
B)  its antibacterial activity is significantly less than that of the single agents. 
C)  the antibacterial activity is sustained for a much prolonged time compared with the single agents. 
D)  the antibacterial activity is sustained for a much shorter time compared with the single agents.

Question 4

What principle does the VITEK series use to determine antimicrobial susceptibility?

Accepted Answer

A)  Turbidimetry 
B)  Redox indicator system 
C)  Hydrolysis of a fluorogenic substrate 
D)  Carbon dioxide concentration 
A)  Turbidimetry 
B)  Redox indicator system 
C)  Hydrolysis of a fluorogenic substrate 
D)  Carbon dioxide concentration

Question 5

Why are aminoglycosides not an effective treatment for meningitis?

Accepted Answer

A)  They do not cross the blood-brain barrier. 
B)  They are nephrotoxic and will harm the patient's kidneys. 
C)  They are ototoxic and will harm the patient's ears. 
D)  They are not effective against Neisseria, Streptococcus, or Haemophilus. 
A)  They do not cross the blood-brain barrier. 
B)  They are nephrotoxic and will harm the patient's kidneys. 
C)  They are ototoxic and will harm the patient's ears. 
D)  They are not effective against Neisseria, Streptococcus, or Haemophilus.

Question 6

All the following organisms often produce $\beta$-lactamase, except

Accepted Answer

A)  Haemophilus influenzae. 
B)  Neisseria gonorrhoeae. 
C)  Moraxella catarrhalis. 
D)  Neisseria meningitidis. 
A)  Haemophilus influenzae. 
B)  Neisseria gonorrhoeae. 
C)  Moraxella catarrhalis. 
D)  Neisseria meningitidis.

Question 7

If the MIC or zone size is interpreted as intermediate 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 or more than can be achieved and 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 or more than can be achieved and for which the clinical response is likely to be less than with a susceptible strain. 
D)  None of the above

Question 8

A man goes to his doctor because he has a cloudy substance dripping from his penis. A Gram stain is performed and gonorrhea is isolated. What is the drug of choice to treat this infection?

Accepted Answer

A)  Gentamicin 
B)  Erythromycin 
C)  Vancomycin 
D)  Ceftriaxone 
A)  Gentamicin 
B)  Erythromycin 
C)  Vancomycin 
D)  Ceftriaxone

Question 9

In vitro testing conditions that can be modified to enhance the expression of oxacillin resistance include all the following, except

Accepted Answer

A)  use Mueller-Hinton media. 
B)  making final test readings after a full 24 hours of incubation. 
C)  incubation of tests at temperatures no greater than 35$\degree$ C. 
D)  preparation of inocula using the direct inoculum suspension procedure. 
A)  use Mueller-Hinton media. 
B)  making final test readings after a full 24 hours of incubation. 
C)  incubation of tests at temperatures no greater than 35$\degree$ C. 
D)  preparation of inocula using the direct inoculum suspension procedure.

Question 10

A 12-year-old girl goes to the doctor complaining of a sore throat, fever, headache, and general malaise. The doctor does a quick strep test that is positive for group A $\beta$-hemolytic Streptococcus. No antibiotic testing is needed because Streptococcus is

Accepted Answer

A)  universally susceptible to penicillin. 
B)  universally susceptible to erythromycin. 
C)  not treated in throat cultures. 
D)  not considered a pathogen in the throat. 
A)  universally susceptible to penicillin. 
B)  universally susceptible to erythromycin. 
C)  not treated in throat cultures. 
D)  not considered a pathogen in the throat.

Question 11

What is the principle of the Etest?

Accepted Answer

A)  Turbidimetry 
B)  Establishing an antimicrobial density gradient in agar 
C)  Carbon dioxide concentration 
D)  Redox indicator system 
A)  Turbidimetry 
B)  Establishing an antimicrobial density gradient in agar 
C)  Carbon dioxide concentration 
D)  Redox indicator system

Question 12

In this method of antimicrobial susceptibility testing, specific volumes of various concentrations of antimicrobial solutions are dispensed into premeasured volumes of molten and cooled agar, which is subsequently poured into standard Petri dishes. Organisms are inoculated onto the plate. What type of antimicrobial susceptibility testing is this?

Accepted Answer

A)  Macrodilution 
B)  Broth dilution 
C)  Disk diffusion 
D)  Agar dilution 
A)  Macrodilution 
B)  Broth dilution 
C)  Disk diffusion 
D)  Agar dilution

Question 13

What is the most critical step in any susceptibility test?

Accepted Answer

A)  Plate streaking 
B)  Organism isolation 
C)  Gram stain identification 
D)  Inoculum preparation 
A)  Plate streaking 
B)  Organism isolation 
C)  Gram stain identification 
D)  Inoculum preparation

Question 14

What broth is recommended in the tube dilution MIC tests?

Accepted Answer

A)  Trypticase soy 
B)  Mueller-Hinton 
C)  Columbia 
D)  Cooked meat 
A)  Trypticase soy 
B)  Mueller-Hinton 
C)  Columbia 
D)  Cooked meat

Question 15

A drug will generally inhibit multiplication of the bacteria so that the patient's immune defense mechanisms are no longer overwhelmed when

Accepted Answer

A)  all the debris and necrotic cells are removed. 
B)  the drug concentration exceeds the MIC for the microbe. 
C)  the patient is not infected with a gram-negative rod. 
D)  two synergistic drugs are used to kill the bacteria. 
A)  all the debris and necrotic cells are removed. 
B)  the drug concentration exceeds the MIC for the microbe. 
C)  the patient is not infected with a gram-negative rod. 
D)  two synergistic drugs are used to kill the bacteria.

Question 16

What is a mechanism for ensuring the testing personnel are proficient in their tasks?

Accepted Answer

A)  Supervisory review of reported results 
B)  Self-assessment checklists 
C)  Periodic competency testing through proficiency surveys 
D)  All of the above 
A)  Supervisory review of reported results 
B)  Self-assessment checklists 
C)  Periodic competency testing through proficiency surveys 
D)  All of the above

Question 17

After the plate is incubated in the Kirby-Bauer test, what occurs?

Accepted Answer

A)  The plate is tested to make sure an isolated organism grew on the plate. 
B)  The diameter of each inhibition zone for each antibiotic is measured using a ruler or caliper. 
C)  The amount of carbon dioxide in the plate is measured to ensure confluent organism growth. 
D)  None of the above. 
A)  The plate is tested to make sure an isolated organism grew on the plate. 
B)  The diameter of each inhibition zone for each antibiotic is measured using a ruler or caliper. 
C)  The amount of carbon dioxide in the plate is measured to ensure confluent organism growth. 
D)  None of the above.

Question 18

What McFarland standard provides turbidity comparable to that of a bacterial suspension containing approximately 1.5 $\times$ 108 colony-forming units (CFU)/mL?

Accepted Answer

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

Question 19

What is the approximate final concentration of organisms in each well of a microdilution tray?

Accepted Answer

A)  3 $\times$ 105 CFU/mL 
B)  1 $\times$ 105 CFU/mL 
C)  4 $\times$ 105 CFU/mL 
D)  5 $\times$ 105 CFU/mL 
A)  3 $\times$ 105 CFU/mL 
B)  1 $\times$ 105 CFU/mL 
C)  4 $\times$ 105 CFU/mL 
D)  5 $\times$ 105 CFU/mL

Question 20

What agencies develop the zone interpretive criteria?

Accepted Answer

A)  CDC and USAMRIID 
B)  U.S. FDA and CDC 
C)  FDA and CLSI 
D)  CLSI and CDC 
A)  CDC and USAMRIID 
B)  U.S. FDA and CDC 
C)  FDA and CLSI 
D)  CLSI and CDC

Exam 13: Antimicrobial Susceptibility Testing

When should antimicrobial susceptibility testing be performed on a bacterial isolate from a clinical specimen?

Therapy of disseminated meningococcal infections and various types of gonococcal (GC) infections are

A combination of antimicrobials is said to show synergism if

What principle does the VITEK series use to determine antimicrobial susceptibility?

Why are aminoglycosides not an effective treatment for meningitis?

All the following organisms often produce β\betaβ -lactamase, except

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

A man goes to his doctor because he has a cloudy substance dripping from his penis. A Gram stain is performed and gonorrhea is isolated. What is the drug of choice to treat this infection?

In vitro testing conditions that can be modified to enhance the expression of oxacillin resistance include all the following, except

A 12-year-old girl goes to the doctor complaining of a sore throat, fever, headache, and general malaise. The doctor does a quick strep test that is positive for group A β\betaβ -hemolytic Streptococcus. No antibiotic testing is needed because Streptococcus is

What is the principle of the Etest?

What is the most critical step in any susceptibility test?

What broth is recommended in the tube dilution MIC tests?

A drug will generally inhibit multiplication of the bacteria so that the patient's immune defense mechanisms are no longer overwhelmed when

What is a mechanism for ensuring the testing personnel are proficient in their tasks?

After the plate is incubated in the Kirby-Bauer test, what occurs?

What McFarland standard provides turbidity comparable to that of a bacterial suspension containing approximately 1.5 ×\times× 108 colony-forming units (CFU)/mL?

What is the approximate final concentration of organisms in each well of a microdilution tray?

What agencies develop the zone interpretive criteria?

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

All the following organisms often produce $\beta$ -lactamase, except

A 12-year-old girl goes to the doctor complaining of a sore throat, fever, headache, and general malaise. The doctor does a quick strep test that is positive for group A $\beta$ -hemolytic Streptococcus. No antibiotic testing is needed because Streptococcus is

What McFarland standard provides turbidity comparable to that of a bacterial suspension containing approximately 1.5 $\times$ 10⁸ colony-forming units (CFU)/mL?