Methicillin-resistant Staphylococcus aureus carriage in a child care center following a case of disease

Objectives: To study the prevalence of methicillin sodium-resistant and methicillin-sensitive Staphylococcus aureus colonization in a child care center following the diagnosis of community-acquired methicillin-resistant S aureus (MRSA) disease in a previously well 21/2-year-old attendee and to determine the optimal site of detection of S aureus. Design: Point prevalence survey and questionnaire administration. Setting: A Toronto, Ontario, child care center. Interventions: Parents were provided with general information. Consenting parents completed a questionnaire and permitted screening of their child at 1 or more of throat, nose, and perianal sites. Families of children who were culture positive for MRSA were offered screening and suppressive therapy. Nasal and perianal swabs were obtained from child care center staff and screened. Results: Of 201 children, 164 (81.6%) had completed questionnaires and had undergone screening at 1 or more sites; 38 staff members (100%) completed questionnaires and were screened. A 26-month-old classroom contact with chronic dermatitis had MRSA detected only on perianal swab. Of 3 adult household contacts of the index case and 2 adult and 1 child contacts of the classroom contact, only the 7-year-old sibling of the classroom contact was positive for MRSA. By pulse-field gel electrophoresis, these isolates were identical and not related to any of the common strains circulating in regional health care institutions. Of 40 children with S aureus (24.4%), 33 had cultures at 3 sites, of which the throat was more sensitive (22 [67%]) than the nostrils (15 [46%]) or perianal sites (8 [24%]). There was a tendency for higher carriage of S aureus in children with certain risk factors, including personal hospitalization (prevalence ratio, 2.9; 95% confidence interval, 0.6-12.1), family member hospitalization (prevalence ratio, 2.0; 95% confidence interval, 0.6-6.6), and visiting the hospital emergency department (prevalence ratio, 3.2; 95% confidence interval, 0.7-14.5), all in the previous 6 months. Conclusions: To our knowledge, this is one of the first recognized cases of MRSA disease and apparent transmission in a child care center. Throat and perianal site screenings have a higher sensitivity in identifying children colonized with S aureus than nasal culturing. Infection with MRSA should be suspected in disease unresponsive to standard antibiotic therapy.