Purpose of review: The concept of methicillin-resistant Staphylococcus aureus (MRSA) associated with broad resistance, nosocomial acquisition, and known risk factors has recently been expanded. A new type of MRSA that is resistant to fewer antibiotics has emerged in pediatric practice since the mid-1990s. These isolates are community acquired and have been reported from diverse geographic regions. Awareness of these organisms is important for appropriate treatment of S. aureus infections in children.
Recent findings: Community-acquired MRSA (CA-MRSA) isolates are similar in many respects to community-acquired methicillin-susceptible S. aureus (CA-MSSA). There are usually no differences in risk factors between children with CA-MRSA infections and those with CA-MSSA infections or their household contacts. In one study, however, multivariate analysis showed that age greater than 1 year and health care contact in the preceding month were significant risk factors for CA-MRSA. Skin and soft tissue infections are the most common manifestations, although serious invasive infections and death may occur. Pneumonia has been reported more often in children with CA-MRSA than in those with CA-MSSA. Clindamycin is an effective therapy for CA-MRSA, but there is a risk for development of clindamycin resistance during treatment of a CA-MRSA that is clindamycin susceptible and inducibly erythromycin resistant. Trimethoprim-sulfamethoxazole is likely to be effective, and linezolid is a new option for treatment.
Summary: The appearance of CA-MRSA has important implications for therapy of infections caused by S. aureus in children. Three specific issues are the development of resistance during clindamycin therapy, insufficient data on the use of trimethoprim-sulfamethoxazole in serious CA-MRSA infections, and the appropriate role for newer antibiotics such as linezolid.