Sensitivity surveillance of streptococci isolates for several antibiotics in Gifu prefecture (2005-2007)

We investigated the susceptibility to antibacterials of streptococci isolated from 8 medical facilities in Gifu prefecture between 2005 and 2007. Strains used in this study include 118 of Group A streptococci, 89 of Group B streptococci, and 58 of group G streptococci. For Group A streptococci, cefteram and imipenem gave the lowest MIC90 at 0.0078 microg/mL, followed by cefditoren and cefcapene at 0.0156 microg/mL and penicillin G, amoxicillin and meropenem at 0.0313 microg/mL. For Group B streptococci, cefteram, cefditoren, cefcapene and imipenem gave the lowest MIC90 at 0.0313 microg/mL, followed by penicillin G and meropenem at 0.0625 microg/mL and amoxicillin at 0.125 microg/mL. For Group G streptococci, cefteram and imipenem gave the lowest MIC90 at 0.0078 microg/mL, followed by penicillin G, cefditoren, cefcapene and meropenem at 0.0156 microg/mL and amoxicillin at 0.0313 microg/mL. With Group A and B streptococci, the susceptibility data obtained in this study were compared with those of strains between 2000 and 2001. As for group A streptococci, the MIC50 and MIC90 of beta-lactam agents were about the same as those of previous study, however the MIC90 of quinolones increased about 2.5-fold and resistant strains were found. As for Group B streptococci, the MIC50 and MIC90 of almost all of the antibacterials were about the same as those of the previous study, however the MIC90 of clarithromycin increased about 10-fold, indicating that the resistant strains are widely spread.