Epidemiology of methicillin-susceptible staphylococcus aureus in a university medical center day care facility

Background: Few data are available on methicillin-susceptible Staphylococcus aureus (MSSA) colonization in day care. We performed a study in a child care center on a medical university campus to study the epidemiology of MSSA in this population. Methods: A cross-sectional study was done on 104 day care attendees and 32 adult employees of the child care center. Swab samples were taken from the nose, oropharynx, axilla, groin, and perirectal area of children, from the nose and oropharynx of employees, and from the environment. Parents and employees completed questionnaires. Swabs were placed in broth, then plated on agar and identified as MSSA by routine methods. Molecular typing was performed. Results: The prevalence of MSSA was 21.15% in children and 28.13% in employees. MSSA was found in 8.72% of environmental samples. Univariate analysis identified 3 risk factors and 5 protective factors for MSSA colonization. In multivariable analysis, only 2 variables remained significantly related to MSSA colonization, with older age remaining as a risk factor and receipt of beta-lactams approaching significance as being protective. Many of the isolates were indistinguishable by molecular typing. Conclusions: The prevalence of MSSA colonization in children and care providers in a university medical center child care center is similar to that of the general population. Children colonized with MSSA tended to be older and to have received fewer courses of antibiotics than children who did not have MSSA. The relatedness of many of the isolates indicates that transmission of MSSA occurred at this child care center.