Community-acquired methicillin-resistant Staphylococcus aureus colonization in healthy children attending an outpatient pediatric clinic

Background. We previously showed that children attending an inner city pediatric emergency department were sometimes asymptomatically colonized with clindamycin-susceptible community-acquired methicillin-resistant Staphylococcus aureus (MRSA) and borderline methicillin-resistant S. aureus (BRSA) as well. We wished to ascertain whether healthy children attending an outpatient clinic were colonized with these organisms. Therefore to estimate the prevalence of community-acquired MRSA and BRSA nasal colonization in a well child population, we cultured children attending an inner city pediatric outpatient clinic. Study design. This was a prospective cross-sectional study conducted from January to August, 1999, at a primary care outpatient facility at the University of Chicago. The target population was 500 healthy children less than or equal to 16 years of age who attended this facility to receive well child care. Results. One hundred twenty-two (24.4%) children were colonized with S. aureus. Three of the 122 (2.5%) S. aureus isolates were MRSA, they came from children who lacked predisposing risk factors and were susceptible to clindamycin, gentamicin, trimethoprim-sulfamethoxazole, rifampin and ciprofloxacin. Two (1.6%) additional S. aureus isolates were BRSA, both children had predisposing risk factors for MRSA colonization. The mecA gene was present in the 3 MRSA isolates and absent in both BRSA isolates. Conclusions. These data document that a reservoir of asymptomatic MRSA colonization exists among healthy children who lack traditional risk factors for MRSA infections.