Community-acquired methicillin-resistant Staphylococcus aureus infections in South Texas children

Background. Community-acquired methicillin-resistant Staphylococcus aureus (CAMRSA) infections have increased dramatically from 1990 to 2000. Objectives. The objectives of this retrospective study were to report the frequency of CAMRSA isolates, to describe the spectrum of disease observed in children infected with CAMRSA and to compare the antibiotic susceptibility patterns of community-acquired and nosocomial methicillin-resistant S. aureus (MRSA) infections. Methods. All cases of S. aureus including MRSA infections were identified by a computer-assisted search of the Vitek system culture results from 1990 to 2000 and review of the minutes of Infection Control Committee meetings. Results. MRSA was isolated from 147 children (77 boys; 2 weeks to 17 years) from October 1, 1990, to December 31, 2000. Seven cases of CAMRSA were identified from 1990 to 1996, and 53 cases were identified from 1997 to 2000 with 35 cases occurring in 2000. Of the 128 children whose medical records were reviewed, 60 (47%) had CAMRSA infections. In 53 (88%) of these 60 children no risk factor for MRSA was identified. Soft tissue infections accounted for 48 (91%) of the 53 cases of the CAMRSA in children without known risk factors. CAMRSA isolates from children without known risk factors were more susceptible to trimethoprim-sulfamethoxazole (98% vs. 82%; P < 0.005) and clindamycin (92% vs. 57%; P < 0.001) and less susceptible to tetracycline (54% vs. 95%; P < 0.001) than were nosocomial MRSA isolates. Conclusions. The emergence of CAMRSA as a cause of common infections may require a change in the initial selection of antibiotics to assure appropriate coverage in critically ill children.