Abstract
Two hundred and sixteen strains of β-hemolytic Streptococcus were detected at five institutions in fiscal years 2007, 2009, and 2011. These strains were divided into three bacterial groups: Streptococcus pyogenes (Group A Streptococcus, GAS), Streptococcus agalactiae (Group B Streptococcus : GBS), and β-hemolytic Streptococcus strains other than GAS or GBS (non-AB). Changes in detection rate and antibiotic sensitivity of these strains were surveyed. No marked change was noted in detection rate, but that of the bacterial group assumed to include Streptococcus equisimilis increased. Regarding antibiotic sensitivity, all bacterial groups were sensitive to penicillin antibiotics. Regarding erythromycin (EM) sensitivity, two of seven GAS strains (28.6%) isolated in 2011 were resistant, showing that resistant strains were present although the number of isolates was small. The EM resistance rate did not markedly change in GBS, but tended to increase in non-AB. Levofloxacin (LVFX) resistance increased yearly in GBS and reached 61.1% in 2011. Resistance was also noted in one non-AB strain in 2011. It is necessary to pay attention to the acquisition of antibiotic resistance in the future.
