Prevalence of Community-Acquired Methicillin Resistant Staphylococcus aureus in Skin and Soft-Tissue Infections

Objective: To determine the prevalence of CA-MRSA in patients presenting to a local hospital with skin and soft tissue infection.

Methods: A total of 139 specimens were submitted during August 2006 for aerobic bacterial culture. Testing was performed using standard culture technique for bacterial identification and susceptibility testing. Confirmation of MRSA identification was performed using oxacillin agar screen. All laboratory testing was performed following Clinical and Laboratory Standards Institute guidelines. Isolates were determined to be CA-MRSA based on the following criteria: Diagnosis of MRSA was made in the outpatient setting or within 48 hours of hospital admission, patient had not been hospitalized within the past year, and patient had no history of surgery within the past year.

Results: Of the 139 clinical specimens tested, 60 were positive for MRSA. Of the MRSA isolates, 41 were identified as CA-MRSA strains. 30 were male, 11 female, 3 Hispanic, 13 African-American, 21 white, and 4 other.

Conclusion: In this study, approximately 68% of MRSA positive cultures were classified as CA-MRSA strains. The incidence of CA-MRSA was highest among whites (50%), while African-Americans (31%), Hispanics (7%), and others (12%) were recovered at a significantly lower incidence. CA-MRSA strains contain toxins which promote increased inflammation and tissue destruction, therefore early detection and appropriate antimicrobial therapy is necessary for infection control.