Objective To assess whether the number of community-acquired MRSA (CA-MRSA) infections in otherwise healthy children has been increasing in Alabama during the study period from 1999-2004 and whether the pattern of infection has changed.
Methods A retrospective chart review was done for patients during the years of 1999-2003 and prospective interviews were done for patients selected for the study during 2003-2004. These patients were screened for enrollment in the study based on their culture results and determination of their risk category. Those patients with positive cultures for CA-MRSA and a low or intermediate risk category assignment were included in the study. Those that were selected as CA-MRSA had a positive culture within 72 hours of admission and no previous MRSA infections. To determine the risk category a questionnaire was utilized to assess the patients' exposure to MRSA and select for only those patients with a low or intermediate risk classification. A low risk patient was one that had no risk factors while intermediate patients were those with a single risk factor, that factor most often being the placement of ear tubes at some point.
Results The incidence of CA-MRSA has been increasing since the year 2000 from 20% to 33% (2001) to 36% (2002) to 52% (2003) of all MRSA patients. Out of all the cases of CA-MRSA over the past five years, 28% of children have shown resistance to clindamycin, 84% to erythromycin, and 46% to ciprofloxacin. 34% of children with suspected CA-MRSA have presented with skin infections (abscess, cellulitis) and 5% with more severe infections like osteomyelitis, pneumonia, or sepsis. These more severe infections have been seen in recent years while the less invasive infections were the only type seen early on in the study (1999-2001).
Conclusions The onset of more invasive infections in recent years suggests that maybe this new CA-MRSA strain of bacteria is more virulent. The steady increase in the number of CA-MRSA indicates that these numbers will continue to rise.