Nasopharyngeal Penicillin-resistant Streptococcus Pneumoniae Strains among Young Children in Japan

OBJECTIVE: A rapid increase of penicillin resistance in Streptococcus pneumoniae has recently been reported in most areas of the world. Penicillin-resistant S. pneumoniae and other resistant bacteria are the principal causes of recurrent acute otitis media (AOM). Penicillin-resistant S. pneumoniae was examined so that we could investigate the bacteriologic and clinical interpretations of nasopharyngeal flora from healthy children. METHODS: We obtained nasopharyngeal swab specimens from healthy children attending a day care center and from children attending a public health examination in Kanazawa, Japan. We also obtained clinical specimens from children with AOM who visited the Kanazawa University Hospital and 4 other hospitals in Ishikawa Prefecture in Japan. RESULTS: The chief bacteria from the children were S. pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. Penicillin-resistant S. pneumoniae was identified in 75% of children attending a day care center. On the other hand, S. pneumoniae was identified in 37% of children who were not attending day care. Of the children with AOM, penicillin-resistant S. pneumoniae was identified in 77%. CONCLUSION: Our results suggest that there is a strong relationship between day care attendance and nasopharyngeal carriage of S. pneumoniae. The carriage rate of penicillin-resistant S. pneumoniae in healthy children in day care centers was very high and similar to the carriage rate of young patients with AOM in Japan.