P187 Withdrawn P188 Serotype distribution and analysis of macrolide- and penicillin-resistance among non-invasive S. pneumoniae isolates in northern Japan

Introduction: Streptococcus pneumoniae is an important human pathogen in community-acquired respiratory infections. S. pneumoniae with resistance to penicillin and other antibiotics is becoming prevalent. In particular, macrolide resistance among S. pneumoniae isolates has risen in recent years worldwide. The increasing incidence of macrolideand penicillin-resistant S. pneumoniae has been a serious problem in Japan. Objectives: The objective of this study was to investigate the prevalence of serotypes, and macrolideand penicillin-resistance among pneumococcal isolates from outpatients with non-invasive infections. Methods: A total of 1,061 non-invasive S. pneumoniae strains isolated from outpatients who visited various hospitals and clinics in Hokkaido, northern main island of Japan in 2011 were analyzed. The presence of macrolide-resistance genes erm (B ) and mef (A/E ), and 3 unaltered pbp genes (pbp1a, pbp2x, and pbp2b) were detected by multiplex PCR. MICs of all isolates against erythromycin and penicillin were measured by E-test. Serotyping of these isolates was performed genetically by sequential multiplex PCR and direct sequencing. Additionally, we developed a novel mutagenic PCR-RFLP assay for discrimination of serotypes 6A, 6B, 6C, and 6D. Results: Among the 1,061 strains, 95.8% and 7.7% isolates were resistant to erythromycin and penicillin, respectively. The erm (B ) and mef (A/E ) genes were detected in 66.4% and 40%, respectively (including 10.7% of the strains carrying both genes). The rate of strains with a single altered pbp gene was 38.8%, with two and three altered pbp genes being 18.4% and 37.9%, respectively. The most frequent serotypes were 6B (17.0%), 19F (15.6%), 23F (12.1%). While most of strainswith these three serotypes harbored erm (B ) and/ormef (A/E ) (>98%), rate of PRSP with three altered pbp genes was highest in 23F (83.6%), followed by 6B (70.3%) and 19F (62.4%). All the serotype15B/C isolates were resistant to erythromycin (MIC: >256 mg/ml). Serotypes included in the 7and 13-valent conjugate vaccines covered 47.7% and 69.3% of isolates, respectively. Conclusion:The present study indicated the spreadofmacrolideand penicillin-resistant strains among non-invasive S. pneumoniae isolates in Hokkaido.