title: Comparative Analysis of Penicillin-Susceptible and Non-Susceptible Isolates of Group B Streptococci by Multilocus Sequence Typing.
abstract: Since Group B Streptococcus (GBS, Streptococcus agalactiae) clinical isolates are believed to be uniformly susceptible to β-lactams, penicillin G has been used as the first-line agent for the prevention and treatment of GBS infections. However, the existence and characteristics of GBS isolates with reduced penicillin susceptibility (PRGBS) have recently been reported in Japan. Moreover, the sequence type (ST) 458 is predominant among the PRGBS in Japan. Although the majority of the PRGBS isolates in Japan have been recovered from respiratory specimens of adults, no information on the genotype of these isolates is available. Therefore, whether ST458 predominates among GBS isolates obtained from such specimens is not known. In this study, we characterized the STs of 38 penicillin-susceptible GBS isolates (PSGBS) recovered from respiratory specimens and compared them to the reported PRGBS STs. ST458, the predominant ST among the PRGBS isolates studied (10/19, 53%), was not found in the PSGBS isolates. Thirty-six PSGBS isolates belonged to the ST1/19/10 group (includes 6 different STs), and the remaining 2 isolates belonged to that of ST23. Further, the PRGBS isolates were divided into the ST1 (3 STs), and ST23 (2 STs) groups. ST458 was not predominant among the PSGBS isolates recovered from respiratory specimens in Japan and may therefore be specific to the PRGBS. Thus, the ST distribution of the PRGBS isolates does not reflect that of the PSGBS.
authors.affiliation: Department of Bacteriology, Nagoya University Graduate School of Medicine.
authors.forename: Ryoko
authors.initials: R
authors.lastname: Yamada
authors.forename: Kouji
authors.initials: K
authors.lastname: Kimura
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Nagano
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Nagano
authors.forename: Satowa
authors.initials: S
authors.lastname: Suzuki
authors.forename: Wanchun
authors.initials: W
authors.lastname: Jin
authors.forename: Jun-Ichi
authors.initials: J
authors.lastname: Wachino
authors.forename: Keiko
authors.initials: K
authors.lastname: Yamada
authors.forename: Keigo
authors.initials: K
authors.lastname: Shibayama
authors.forename: Yoshichika
authors.initials: Y
authors.lastname: Arakawa
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005838:Genotype; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D058885:Multilocus Sequence Typing; D010406:Penicillins / Q000494:pharmacology*; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000382:microbiology; D013290:Streptococcal Infections / Q000453:epidemiology / Q000382:microbiology*; D013292:Streptococcus agalactiae / Q000145:classification* / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D055815:Young Adult
chemical_list: D010406:Penicillins