RESUMO
We investigated the susceptibility of Streptococcus pneumoniae isolated from 8 hospitals in Chiba prefecture during 2012-2013. We further checked the serotype of S. pneumoniae derived from invasive pneumococcal disease (IPD). We tested for antimicrobial susceptibility in 256 clinical isolates (137 isolates from children, 119 isolates from adults) for 25 drugs. In MIC50 and MIC90, there were very little differences between children and adults, but there were 3 isolates from adults which were resistant to levofloxacin. The most major serotypes were 15A and 3 in IPD. Additionally there was no isolation of the type contained in the 7-valent pneumococcal conjugate vaccine in children, so it seems that the vaccination is very effective for children. Furthermore, in contrast with our preceding report, a decreasing was seen in PCG resistant proportion of S. pneumoniae. The maximum PCG-MIC was 2 µg/mL.