Prevalence of and risk factors for community-acquired methicillin-resistant and methicillin-sensitive staphylococcus aureus colonization in children seen in a practice-based research network.

OBJECTIVE: We sought to define the prevalence of and risk factors for methicillin-resistant Staphylococcus aureus nasal colonization in the St Louis pediatric population.
METHODS: Children from birth to 18 years of age presenting for sick and well visits were recruited from pediatric practices affiliated with a practice-based research network. Nasal swabs were obtained, and a questionnaire was administered.
RESULTS: We enrolled 1300 participants from 11 practices. The prevalence of methicillin-resistant S aureus nasal colonization varied according to practice, from 0% to 9% (mean: 2.6%). The estimated population prevalence of methicillin-resistant S aureus nasal colonization for the 2 main counties of the St Louis metropolitan area was 2.4%. Of the 32 methicillin-resistant S aureus isolates, 9 (28%) were health care-associated types and 21 (66%) were community-acquired types. A significantly greater number of children with community-acquired methicillin-resistant S aureus were black and were enrolled in Medicaid, in comparison with children colonized with health care-associated methicillin-resistant S aureus. Children with both types of methicillin-resistant S aureus colonization had increased contact with health care, compared with children without colonization. Methicillin-sensitive S aureus nasal colonization ranged from 9% to 31% among practices (mean: 24%). The estimated population prevalence of methicillin-sensitive S aureus was 24.6%. Risk factors associated with methicillin-sensitive S aureus colonization included pet ownership, fingernail biting, and sports participation.
CONCLUSIONS: Methicillin-resistant S aureus colonization is widespread among children in our community and includes strains associated with health care-associated and community-acquired infections.