Streptococcus pneumoniae carriage in children attending 59 Canadian child care centers

Objectives: To determine the prevalence of Streptococcus pneumoniae nasopharyngeal carriage, antibiotic resistance patterns, and serotypes; to examine the variability of microbiological findings between child care centers; and to determine risk factors for antibiotic resistance. Design: Point prevalence survey. Setting: Licensed child care centers in Toronto, Ontario. Participants: Healthy children attending the centers. Main Outcome Measures: Prevalence (simple and adjusted for clustering) of carriage, antibiotic resistance, and serotypes; multivariate analysis of risk factors for resistance. Results: Of 1322 children from 59 centers, 586 (44.3%) carried 599 S pneumoniae isolates. On the day of study, 129 (10.7%) of 1203 children for whom a questionnaire was completed were taking antibiotics and 336 (227.9%) had taken them in the previous month. Decreased susceptibility to penicillin was found in 102 isolates (17.0%) and 82 (13.7%) were resistant to multiple antibiotics. The most common serotypes, in order, were 6B, 23F, 6A, 19F, 14, 11A, and 19A, composing 78% of all isolates. Microbiological results from individual centers were variable, but the overall prevalence of carriage, antibiotic resistance, and serotypes was not significantly different when adjusted for effects of clustering within centers. Multiple logistic regression determined that age younger than 24 months and antibiotic use within the previous month were significant risk factors for carriage of S pneumoniae resistant to penicillin, sulfamethoxazole-trimethoprim, and erythromycin. Conclusions: Efforts to reduce antibiotic use in children should be particularly directed toward young children attending child care centers. Studies of infectious diseases in child care centers should consider clustering of pathogens or factors promoting transmission within centers that may result in variability between centers.