Nasal carriage of Streptococcus pneumoniae in healthy children and adults in northern Taiwan.

A total of 427 subjects were surveyed for the carriage of Streptococcus pneumoniae before the introduction of pneumococcal conjugate vaccine in northern Taiwan. Positive results were identified in 27% of 94 children attending 6 classes in a child care center (CCC), 14% of 122 pupils attending 4 classes in 2 elementary schools, and 1.4% of 74 adolescents attending 3 classes in a junior middle school. None of 137 health care workers working in neonatal intensive care units of a university-affiliated hospital was colonized with S. pneumoniae. Three (12%) of 25 isolates from the children attending the CCC were susceptible to penicillin (MIC <0.1 microg/mL), whereas 8 (44%) of 18 isolates from the pupils and adolescents were susceptible (P = 0.0312). Of the 43 isolates, 11 serotypes were identified and serotypes/serogroups 6 (13 isolates), 23 (10 isolates), and 19 (7 isolates) were the 3 most common serotypes/serogroups. The genotypes of the 43 isolates were diverse, but it was not infrequently seen that several isolates from the subjects in a single class shared a common genotype. Conclusively, the carriage rate of S. pneumoniae is inversely correlated with the age of the subjects. The isolates from the children attending the CCC had a significantly higher penicillin-nonsusceptible rate than those from the pupils and adolescents. Transmission of the same clone in a single class may have frequently occurred.