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 met hicillin-sensitive Staphylococcus aureus colonization in a child care cente r following the diagnosis of community-acquired methicillin-resistant S aur eus (MRSA) disease in a previously well 21/2-year-old attendee and to deter mine 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 p arents completed a questionnaire and permitted screening of their child at 1 or more of throat, nose, and perianal sites. Families of children who wer e culture positive for MRSA were offered screening and suppressive therapy. Nasal and perianal swabs were obtained from child care center staff and sc reened. Results: Of 201 children, 164 (81.6%) had completed questionnaires and had undergone screening at 1 or more sites; 38 staff members (100%) completed q uestionnaires and were screened. A 26-month-old classroom contact with chro nic dermatitis had MRSA detected only on perianal swab. Of 3 adult househol d contacts of the index case and 2 adult and 1 child contacts of the classr oom contact, only the 7-year-old sibling of the classroom contact was posit ive for MRSA. By pulse-field gel electrophoresis, these isolates were ident ical and not related to any of the common strains circulating in regional h ealth care institutions. Of 40 children with S aureus (24.4%), 33 had cultu res 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 h igher 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% confid ence interval, 0.6-6.6), and visiting the hospital emergency department (pr evalence ratio, 3.2; 95% confidence interval, 0.7-14.5), all in the previou s 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.