Posttest for CME Credits

1. Which of the following statements about Staphylococcus aureus is most accurate?

a. Advances in medical care of patients have limited the emergence of complex infections caused by S. aureus.

b. S. aureus is the most common cause of infective endocarditis in major medical centers in the developed world.

c. Rates of mortality due to methicillin-resistant S. aureus (MRSA) are similar to those due to methicillin-susceptible S. aureus.

d. Risk factors for community-acquired MRSA (CA-MRSA) infections are essentially the same as those for hospital-acquired MRSA (HA-MRSA) infections.

2. CA-MRSA infections

a. Are frequently reported to be caused by strains containing staphylococcal cassette chromosome (SCC) mec type II.

b. Have been reported primarily in the United States.

c. Usually present as pyogenic skin and soft-tissue infections (SSTIs) in previously healthy persons.

d. Are usually not responsive to non–β-lactam antibiotics (such as clindamycin and tetracycline).

3. Which of the following statements is most accurate regarding the contribution of microbial surface components recognizing adhesive matrix molecules (MSCRAMMs) to the pathology of S. aureus?

a. MSCRAMMs are responsible for the initial adherence step in S. aureus infection.

b. MSCRAMMs are usually expressed during the stationary growth phase of S. aureus and help to initiate spread to other sites.

c. The expression of MSCRAMMs is the same across all strains of S. aureus.

d. MSCRAMMs are responsible for production of necrotizing toxins.

4. Which of the following statements about Panton-Valentine leukocidin (PVL) is most accurate?

a. PVL is most commonly found in hospital-acquired strains of MRSA.

b. USA300 strains of MRSA generally do not contain PVL.

c. There is a strong epidemiological association between PVL and CA-MRSA infections.

d. PVL has not shown evidence of causing necrosis.

5. Which of the following is most accurate with regard to resistance in S. aureus?

a. Resistance to vancomycin and glycopeptides is now commonplace.

b. Methods to detect heteroresistant vancomycin-intermediate S. aureus have been standardized and are sensitive.

c. There is evidence that S. aureus strains with vancomycin MICs that are increased (>1 µg/mL) but still within the susceptible range are associated with treatment failures.

d. Decreased susceptibility to vancomycin does not appear to affect the efficacy of other antibiotics.

6. Which of the following statements is most accurate?

a. Higher doses of vancomycin have consistently yielded better outcomes in the treatment of S. aureus infection.

b. Glycopeptide-intermediate S. aureus strains may have altered cellular physiology, resulting in cell-wall thickening.

c. CA-MRSA strains, in general, have higher vancomycin MICs than do HA-MRSA strains.

d. Resistance to linezolid, but not to daptomycin, has been demonstrated in MRSA.

7. CA-MRSA SSTIs

a. Usually present as abscesses or cellulitis on the extremities.

b. Require hospitalization in the vast majority of cases.

c. Do not tend to recur.

d. Cannot be transmitted to others.

8. Which of the following statements is most accurate with regard to treatment of SSTIs caused by CA-MRSA?

a. Abscesses <5 cm in diameter should be treated with antibacterial therapy alone.

b. Vancomycin no longer appears to be a viable option for treatment.

c. Linezolid, daptomycin, and tigecycline are all approved for the treatment of SSTIs caused by MRSA.

d. Clindamycin has been found to be effective for treatment of these infections in studies of adults.

9. Which of the following statements does NOT accurately differentiate CA-MRSA pneumonia from health care–associated or hospital-acquired pneumonia (HCAP and HAP, respectively)?

a. CA-MRSA pneumonia often occurs in young and previously healthy individuals, compared with HAP, which often affects elderly patients with comorbid underlying diseases.

b. Influenza-like illness frequently is reported to occur before CA-MRSA pneumonia.

c. Traditionally, HCAP/HAP caused by MRSA usually involves strains containing SCCmec type IV and PVL, whereas CA-MRSA pneumonia usually is caused by strains containing SCCmec types I–III.

d. Negative blood culture results are common in HAP.

10. Which of the following statements best describes therapy for pneumonia caused by MRSA?

a. The rate of positive outcomes following vancomycin therapy for MRSA pneumonia is significantly improved when the vancomycin trough levels are increased to >15 µg/mL.

b. Although linezolid does not penetrate into the lung as well as vancomycin, it appears to produce outcomes similar to those produced by vancomycin in the treatment of MRSA pneumonia.

c. Clinical trials demonstrate that vancomycin monotherapy is the best treatment for CA-MRSA pneumonia.

d. If MRSA pneumonia is suspected, initiation of empirical antibiotic therapy for MRSA should be started immediately after culture samples (such as blood, sputum, and pleural specimens) are obtained.

11. In a study by Fowler et al. from 2003 (AMA Arch Int Med 2003; 163:2066–72), the predictors of clinical complication from S. aureus bacteremia included all of the following EXCEPT:

a. Community acquisition of infection.

b. Persistent fever at 72 h.

c. Positive blood culture result 48–96 h after initial positive blood culture result.

d. WBC count <10,000 cells/mm³.

12. Which of the following statements is most accurate with regard to antimicrobial therapy for MRSA bacteremia or native-valve endocarditis?

a. The combination of vancomycin and rifampin has been definitively proven to improve outcomes in treatment of MRSA bacteremia and native-valve endocarditis, compared with vancomycin alone.

b. Daptomycin has not been approved by the US Food and Drug Administration for the treatment of left-sided S. aureus endocarditis.

c. When MRSA bacteremia is treated with vancomycin, clinical outcomes are as likely to be successful when the MIC is 2 µg/mL as when the MIC is <0.5 µg/mL.

d. Clindamycin monotherapy is a useful option for treating endocarditis.

Answer Sheet and Instructions

Please indicate your answers to the CME posttest by circling 1 answer for each question.

1. A B C D

2. A B C D

3. A B C D

4. A B C D

5. A B C D

6. A B C D

7. A B C D

8. A B C D

9. A B C D

10. A B C D

11. A B C D

12. A B C D

There is no fee to complete this test. Completed tests may be mailed or faxed to Boston University School of Medicine.

Mailing instructions. After filling out the answer sheet, please mail this form and the program evaluation to MRSA: An Evolving Clinical Challenge, CME Program: Course code E.MRSAFUS07, Continuing Medical Education, Boston University School of Medicine, 715 Albany St., A305, Boston, MA 02118.

Faxing instructions. After filling out the answer sheet, please fax this form and the program evaluation to MRSA: An Evolving Clinical Challenge, CME Program: Course code E.MRSAFUS07, Continuing Medical Education, Boston University School of Medicine (fax: 617-638-4905).

If you have any questions, please call 617-638-4605.

Program Evaluation

Name: Degree:

Specialty:

Institution:

Address:

City: State: Country: Zip Code:

Telephone: Fax:

E-mail:

Are you licensed to practice medicine in the United States? Yes, No

The amount of time it took you to complete and review the journal supplement and complete this test was h (maximum, 1.45 h).

Please take a few minutes to answer these questions regarding the journal supplement after you have completed the course and, if applicable, the test. Your responses will help us to improve the content and presentation of future journal supplements.

1. How would you rate this activity overall? (5 = excellent, 1 = poor; please circle one)

2. In your opinion, did you perceive any commercial bias?

Yes

If yes, please explain:

3. Do you plan on making any changes in your practice as a result of this activity?

Yes

If yes, please explain:

4. What barriers, if any, do you anticipate encountering as you make changes in your practice?

May we contact you in the future to determine whether you made changes? Yes No

5. Do you feel that each of the following objectives were met? (NA, not applicable.)

5. Do you feel that each of the following objectives were met? (NA, not applicable.)

Identify the increasing incidence of MRSA in US hospitals and in communities. Yes No Partially NA

Identify virulence factors found in MRSA isolates. Yes No Partially NA

Understand what properties define MRSA isolates that are resistant or intermediately resistant to vancomycin; define heteroresistance in MRSA.

Yes No Partially NA

Review the efficacy data for antibiotics used in the treatment of MRSA complicated skin and

skin-structure infections.

Yes No Partially NA

Identify the clinical syndromes found in patients with MRSA pneumonia, as well as the antibiotics used to treat it.

Yes No Partially NA

Understand the criteria used to characterize bacteremic infections and the antibiotics available to treat MRSA bacteremia.

Yes No Partially NA

6. Do you feel that the information in this activity was based on the best evidence available?

Yes

No

If no, please explain:

7. Which of the following competency areas do you feel have been improved as a result of this activity? (Mark all that apply.)

Patient care Professionalism Practice-based learning

Medical knowledge System-based practice Communication skills

8. Please suggest topics for future activities.

9. Please rate the content of this activity. (5 p excellent, 1 p poor; please circle one)

Timely, up-to-date? 5 4 3 2 1

Relevant to your practice? 5 4 3 2 1

10. General comments.