Emergence of community-acquired methicillin-resistant Staphylococcus aureus soft tissue infections

Our objective is to describe the changing incidence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) and its treatment within East Tennessee.

A retrospective chart review of 245 patients treated with incision and drainage of soft tissue infections from March 2000 to September 2005 was completed. Consent was obtained from our local institutional review board. Forty patients were excluded because no cultures were recorded or because they failed the criteria for the diagnosis of CA-MRSA. We examined our data using chi2 analysis. P value of less than .05 was considered statistically significant.

The most common organism cultured was CA-MRSA (33%; 67 of 205). Non-CA-MRSA accounted for 4% (9 of 205). The age of patients ranged from 1 month to 21 years, with a mean age of 6.5 years. Stratified by year, the incidence of positive cultures for CA-MRSA has increased 159% since 2004 and 868% since 2003. In addition, the average age of patients has decreased from 8.3 years in 2000 to 6.1 years in 2005.

Community-acquired MRSA has emerged as the dominant source of soft tissue infection requiring incision and drainage regardless of site in East Tennessee. This has caused a change in the choice of empiric antibiotic treatment of soft tissue abscesses in our region. These infections now account for the third most common reportable disease to the Department of Health in East Tennessee.