title: Screening for group B streptococci with reduced penicillin susceptibility in clinical isolates obtained between 1977 and 2005.
abstract: Group B streptococcus (GBS; Streptococcus agalactiae) is a leading cause of neonatal invasive infections, and until recently, it was thought to be completely susceptible to penicillin. However, we recently identified several clinical GBS isolates with reduced penicillin susceptibility (PRGBS) whose minimum inhibitory concentrations of penicillin were >0.12 μg/ml, which is above the susceptibility breakpoint set by the Clinical and Laboratory Standards Institute. These PRGBS were isolated between 1995 and 2005 in Japan; whether these PRGBS existed in Japan before 1995 is unknown. In the study described here, we screened for PRGBS among 349 clinical GBS isolates obtained in Japan between 1977 and 2005 using the previously developed disk diffusion method for the detection of PRGBS. With this method, we selected 6 PRGBS candidates and confirmed that 1 isolate was PRGBS, using agar dilution method, including oxacillin, ceftizoxime, and penicillin-binding protein 2X (PBP2X) gene sequencing analysis. This isolate was obtained from sputum in 2005, and we could not detect PRGBS isolates before 1995 in this investigation.
authors.affiliation: Department of Bacteriology, Nagoya University Graduate School of Medicine, Nagoya, Japan. koujikim@med.nagoya-u.ac.jp
authors.forename: Kouji
authors.initials: K
authors.lastname: Kimura
authors.forename: Yasunobu
authors.initials: Y
authors.lastname: Nishiyama
authors.forename: Seiichi
authors.initials: S
authors.lastname: Shimizu
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Wachino
authors.forename: Mari
authors.initials: M
authors.lastname: Matsui
authors.forename: Satowa
authors.initials: S
authors.lastname: Suzuki
authors.forename: Kunikazu
authors.initials: K
authors.lastname: Yamane
authors.forename: Keigo
authors.initials: K
authors.lastname: Shibayama
authors.forename: Yoshichika
authors.initials: Y
authors.lastname: Arakawa
mesh_terms: D006801:Humans; D007564:Japan / Q000453:epidemiology; D008826:Microbial Sensitivity Tests; D010403:Penicillin Resistance; D010406:Penicillins / Q000494:pharmacology; D015995:Prevalence; D017422:Sequence Analysis, DNA; D013290:Streptococcal Infections / Q000453:epidemiology* / Q000382:microbiology; D013292:Streptococcus agalactiae / Q000187:drug effects / Q000302:isolation & purification*
chemical_list: D010406:Penicillins