Rate of nasopharyngeal carriage, antimicrobial resistance and serotype of Streptococcus pneumoniae among children in northern Taiwan.

Multiple-antibiotic-resistant strains of Streptococcus pneumoniae are isolated from clinical specimens in Taiwan with increasing frequency. This study aimed to define the carriage rate of S. pneumoniae among children in northern Taiwan, and to determine the antibiotic susceptibility and the serotype incidence of these isolates. Nasopharyngeal swabs were taken from a total of 478 children (age, 1 month-14 years) who sought medical care only for non-infectious disease or routine vaccination at our hospital between July 1998 and November 1999. S. pneumoniae was isolated from 95 patients, and the collected isolates were available for analysis. All pneumococcal isolates were serotyped and their antimicrobial susceptibility tested by standard methods. The total rate of pneumococcal carriage in the study population was 19.9% and the isolation rate was higher in children aged between 2 and 5 years. Only 10 (10.5%) of the isolates were susceptible to penicillin (minimum inhibitory concentration [MIC], < or = 0.06 microg/mL); 47 (49.5%) isolates were intermediately resistant (MIC, 0.12-1 microg/mL) and 38 (40%) were highly resistant (MIC, > or = 2 microg/mL). Among the 95 S. pneumoniae isolates, the common serotypes were 23F (22%), 6B (18.9%), 19F (18.9%), and 14 (8.4%). Evaluation of the results showed that serotypes 23F (24.7%), 19F (21.2%), 6B (15.3%), and 14 (9.4%) composed 70.6% of all penicillin-non-susceptible S. pneumoniae isolates. The significant rate of isolation of penicillin-non-susceptible S. pneumoniae from children indicates that both the judicious use of antibiotics and the availability of conjugate pneumococcal vaccines are the most appropriate strategy to reduce the carriage of resistant pneumococci.