1. Choose the correct statement(s) regarding the white blood cell (WBC) count and differential
A. WBC are usually elevated in response to infection
B. The normal range of the WBC is 12,500-20,000 cells/mm3 (12.5-20.0 × 109/L)
C. WBC is nonspecific and can be elevated in response to a number of noninfectious conditions
D. Neutrophils are the most common type of WBC in the blood
2. The inflammatory process initiated by infection can set up a complex host responses which include:
A. Activation of the complement cascade
B. An increase in the erythrocyte sedimentation rate
C. Elevations of C-reactive protein
D. Increased production of interleukins and tumor necrosis factor
3. Which of the following circumstances would not be considered colonization with normal flora?
A. S. epidermidis found on the skin
B. S. aureus in the bloodstream
D. Viridans streptococci found in the nasopharnx
4. Choose the correct statement(s) regarding the Gram stain and use of cultures to identify potential pathogens
A. The Gram stain may provide a presumptive diagnosis and identify whether the pathogen is Gram-positive or negative and a bacillus or cocci
B. Cultures can provide definitive pathogen identification and differentiate organisms on the basis of biochemical characteristics
C. Every effort should be made to avoid culture contamination
D. Even with automated systems, detection of bacteria or fungi within a few hours is not yet possible
5. Although widely employed, the use of hybridization probes is often limited by their lack of sensitivity.
6. Which of the following is incorrect regarding the use of nucleic acid amplification?
A. Polymerase chain reaction (PCR) is based on the capability of a DNA polymerase to copy and elongate a targeted strain of DNA
B. Each PCR cycle doubles the amount of DNA originally present
C. PCR techniques are useful for detecting fastidious or slowing growing organisms
D. Gene markers for resistance for M. tuberculosis and methicillin-resistant S. aureus are two examples where PCR techniques have been employed
7. The benefit of rapid diagnostic technology is to:
A. Quickly identify and or rule out infectious pathogens
B. Streamline antimicrobial therapy
C. Improve infection control measures such as isolation
8. One limitation of microtiter MIC testing is that:
A. There is a limited ability to automate the test procedures
B. Microtiter MICs have little to no value in the contemporary management of infections
C. Microtiter MICs may overestimate in vivo beta-lactam activity
D. There is a wide variation in the MIC test procedures due to inadequate standardization
9. Which of the following is incorrect regarding MIC testing?
A. Defined as the lowest concentration of a given antimicrobial that will kill (99.9%) of the patient's organism after 18-24 hours incubation
B. Defined as the lowest concentration of given antimicrobial that will visually inhibit the organism from growing after 18-24 hours incubation
C. Kirby-Bauer Test is a qualitative MIC test that can be used for organisms that grow rapidly on artificial media with MIC results expressed as mg/L
D. An E-test can be used as quantitative test expressed as mg/L to measure a MIC
10. MM is a patient with pneumonia and a lung abscess. Staphylococcus aureus (susceptible to vancomycin via microtiter MICs) grew from a properly-obtained sample of the patient's sputum. Vancomycin therapy was started, but the patient has not responded to 7 days of therapy. Which of the following would be the LEAST LIKELY explanation for the failure?
A. The presence of vancomycin-resistant Staphylococcus aureus (VRSA)
B. A peak vancomycin serum concentration less than 25 mcg/mL (mg/L; 17 µmol/L)
C. Inadequate penetration of the vancomycin to the site of the infection
D. An undetectable vancomycin serum trough concentration
11. Which of the following statements is NOT true concerning antimicrobial susceptibility testing and its application to the management of infections?
A. An infection due to an antimicrobial-resistant organism will not respond to treatment with maximal doses
B. A modification of the disk diffusion test method can be used to detect beta-lactamase production
C. Automated susceptibility test systems can interface with pharmacy records to help assess appropriateness of antimicrobial therapy.
D. Newly-developed testing methods for Mycobacteria have reduced susceptibility reporting time to less than 28 days
12. A patient has a lung infection due to Pseudomonas aeruginosa. He currently is receiving therapy with a fluoroquinolone that on average produces a peak serum concentration of 5 mcg/mL (mg/L) and an AUC of 100. The MIC for this fluoroquinolone against his infecting pathogen is 2 mcg/mL (mg/L). Which of the following statements is TRUE?
A. The data provided are incomplete, since the pharmacodynamic predictor of activity for fluoroquinolones is the time above the MIC
B. The fluoroquinolone's peak-to-MIC ratio is optimized for this pathogen
C. The fluoroquinolone's AUC-to-MIC ratio is optimized for this pathogen
D. The fluoroquinolone should be avoided due to concern for development of resistance
13. Which of the following statements is FALSE concerning "once-daily" [extended interval] aminoglycoside dosage regimens?
A. The higher doses produce higher peak serum concentrations which maximize antimicrobial activity
B. Peak and/or mid-dose serum concentrations should be routinely monitored
C. Nomograms can be used to determine dosage regimens.
D. Limitations in the clinical studies of "once daily" regimens has prevented widespread use
14. Which of the following methods would be LEAST APPROPRIATE for determining the individual antimicrobial serum concentrations during a clinical study that evaluates the effectiveness of the combination of two antimicrobial agents to treat pneumonia?
A. Fluorescence polarization immunoassay
D. High-pressure liquid chromatography
15. A microtiter fractional inhibitory concentration experiment is performed to assess the effects of a combination of a new fluoroquinolone and a new aminoglycoside. The following data are generated:
A. Fluoroquinolone MIC: 1 mcg/mL (mg/L)
B. Aminoglycoside MIC: 1 mcg/mL (mg/L)
C. Lowest concentration of the fluoroquinolone that inhibits growth in the presence of aminoglycoside: 0.1 mcg/mL (mg/L)
D. Lowest concentration of aminoglycoside that inhibits growth in the presence of fluoroquinolone: 0.2 mcg/mL (mg/L)
16. Which of the following statements is FALSE concerning special in vitro tests of antimicrobial susceptibility?
A. Demonstration of in vitro antagonism for two antimicrobials correlates strongly with in vivo antagonism
B. MBCs can be helpful to guide antimicrobial treatment of infections such as endocarditis
C. Timed-kill curve tests can be used determine the effect of concentration on antimicrobial killing activity
D. The administration interval can be prolonged for an antimicrobial with a postantibiotic effect
17. Which figure(s) represent(s) bacterial growth phase in the presence of a fully susceptible antibiotic?
18. Which figure(s) represent(s) resistant bacteria in the presence of an antibiotic?