title: Classification of group B streptococci with reduced β-lactam susceptibility (GBS-RBS) based on the amino acid substitutions in PBPs.
abstract: All clinical isolates of group B Streptococcus (GBS; Streptococcus agalactiae) are considered uniformly susceptible to β-lactams, including penicillins. However, GBS with reduced penicillin susceptibility (PRGBS) were first identified by our group in Japan and have also been reported from North America. PRGBS are non-susceptible to penicillin because of acquisition of amino acid substitutions near the conserved active-site motifs in PBP2X. In particular, V405A and Q557E are considered the key amino acid substitutions responsible for penicillin non-susceptibility. We revealed that in addition to the substitutions in PBP2X, an amino acid substitution in PBP1A confers high-level cephalosporin resistance in GBS. As the number of publications on GBS with reduced β-lactam susceptibility (GBS-RBS), especially PRGBS, and concomitantly the need for a systematic classification of GBS-RBS is increasing, we propose here a classification of GBS-RBS based on the amino acid substitutions in their PBPs.
authors: 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: Kouji
authors: K
authors: Kimura
authors: Department of Health and Medical Sciences, Shinshu University Graduate School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan.
authors: Noriyuki
authors: N
authors: Nagano
authors: Department of Bacteriology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
authors: Yoshichika
authors: Y
authors: Arakawa
mesh_terms: D019943:Amino Acid Substitution; D024881:Drug Resistance, Bacterial; D006801:Humans; D007564:Japan; D009656:North America; D046915:Penicillin-Binding Proteins / Q000235:genetics*; D013292:Streptococcus agalactiae / Q000187:drug effects* / Q000235:genetics*; D047090:beta-Lactams / Q000494:pharmacology*
chemical_list: D046915:Penicillin-Binding Proteins; D047090:beta-Lactams
keywords: PRGBS; Streptococcus agalactiae; group B streptococci with reduced penicillin susceptibility; non-susceptibility