title: High isolation rate of MDR group B streptococci with reduced penicillin susceptibility in Japan.
abstract: OBJECTIVE
  In Japan, the isolation rate of group B Streptococcus (GBS) with reduced penicillin susceptibility (PRGBS) was 2.3% between 2005 and 2006. However, no data on this have been available since then; moreover, the isolation rate of MDR-PRGBS has never been reported. The aim of this study was to obtain recent data on the PRGBS isolation rate and to investigate, for the first time, the isolation rate of MDR-PRGBS.
  
  
  METHODS
  We collected 306 clinical GBS isolates from various regions in Japan between January 2012 and July 2013. The MICs of penicillin G, oxacillin, ceftizoxime and ceftibuten for all GBS isolates and the MICs of erythromycin and levofloxacin for PRGBS isolates were determined by the agar dilution method. The mutations in the genes involved in antibiotic resistance and antibiotic resistance genes were analysed by PCR and DNA sequencing.
  
  
  RESULTS
  We detected 45 clinical PRGBS isolates, with a PRGBS isolation rate among GBS of 14.7% (45/306). Among the PRGBS isolates, 32 (32/45, 71.1%) and 43 (43/45, 95.6%) were resistant/non-susceptible to erythromycin and levofloxacin, respectively. Furthermore, 31 PRGBS isolates, which constituted 68.9% of the PRGBS (31/45) and 10.1% of the GBS (31/306), respectively, were resistant/non-susceptible to both macrolides and fluoroquinolones, indicating multidrug resistance.
  
  
  CONCLUSIONS
  These results suggest that the number of clinical PRGBS isolates with a tendency to multidrug resistance increased rapidly between 2005-06 and 2012-13 in Japan.
authors.affiliation: Department of Bacteriology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
authors.forename: Tomomi
authors.initials: T
authors.lastname: Seki
authors.affiliation: Department of Bacteriology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan koujikim@med.nagoya-u.ac.jp.
authors.forename: Kouji
authors.initials: K
authors.lastname: Kimura
authors.affiliation: Department of Bacteriology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
authors.forename: Megan E
authors.initials: ME
authors.lastname: Reid
authors.affiliation: Department of Bacteriology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Miyazaki
authors.affiliation: Department of Bacteriology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Banno
authors.affiliation: Department of Bacteriology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
authors.forename: Wanchun
authors.initials: W
authors.lastname: Jin
authors.affiliation: Department of Bacteriology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Wachino
authors.affiliation: Department of Bacteriology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Yamada
authors.affiliation: Department of Bacteriology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
authors.forename: Yoshichika
authors.initials: Y
authors.lastname: Arakawa
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024901:Drug Resistance, Multiple, Bacterial; D005798:Genes, Bacterial; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008826:Microbial Sensitivity Tests; D010400:Penicillin G / Q000494:pharmacology; D010403:Penicillin Resistance; D010406:Penicillins / Q000494:pharmacology*; D017422:Sequence Analysis, DNA; D013290:Streptococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D013292:Streptococcus agalactiae / Q000187:drug effects* / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents; D010406:Penicillins; D010400:Penicillin G