Community-Acquired Methicillin-Resistant Staphylococcus aureus in Southern New England Children

Abstract

Objective. This study was performed to understand the epidemiology of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections in southern New England children. Methods. A retrospective review was conducted of the medical records of children 0 to 18 years old with MRSA isolated by the Rhode Island Hospital microbiology laboratory (Providence, RI) between 1997 and 2001. A case was classified as either health care-associated MRSA (HCA-MRSA) or CA-MRSA based on time of culture and other strict criteria. The spectrum of illness of the HCA-MRSA and CA-MRSA cases was compared, as were the antibiotic-susceptibility patterns of their isolates. Risk factors for CA-MRSA acquisition were identified, and molecular subtyping of selected isolates was performed. Results. Between 1997 and 2001, S aureus was isolated from 1063 children. Of these children, 57 had MRSA. During this period, both the absolute number of MRSA cases and the proportion of S aureus cases due to MRSA rose more than threefold due to increases in both CA-MRSA and HCA-MRSA infections. Of the 57 MRSA cases, 23 (40%) were CA-MRSA. CA-MRSA patients were more likely to have skin/soft-tissue infections than HCA-MRSA patients (83% vs 38%). Risk factors for acquisition of MRSA including intrafamilial spread, frequent antibiotic exposure, and child-care attendance were identified in 8 of the 23 (35%) CA-MRSA patients. CA-MRSA isolates were more likely to be susceptible to non-β-lactam antibiotics than HCA-MRSA isolates. All isolates were vancomycin susceptible. Conclusions. MRSA accounts for an increasing proportion of all pediatric S aureus infections in southern New England. A significant percentage of these cases are due to CA-MRSA. Pediatricians should have heightened suspicion for CA-MRSA in children with presumed S aureus infections, especially if they have skin/soft-tissue infections or risk factors for MRSA acquisition.