title: Complete sequences of six penicillin-binding protein genes from 40 Streptococcus pneumoniae clinical isolates collected in Japan.
abstract: All six penicillin-binding protein (PBP) genes, namely, pbp1a, pbp1b, pbp2a, pbp2b, pbp2x, and pbp3, of 40 Streptococcus pneumoniae clinical isolates, including penicillin-resistant S. pneumoniae isolates collected in Japan, were completely sequenced. The MICs of penicillin for these strains varied between 0.015 and 8 microg/ml. In PBP 2X, the Thr550Ala mutation close to the KSG motif was observed in only 1 of 40 strains, whereas the Met339Phe mutation in the STMK motif was observed in six strains. These six strains were highly resistant (MICs >/= 2 microg/ml) to cefotaxime. The MICs of cefotaxime for 27 strains bearing the Thr338Ala mutation tended to increase, but the His394Leu mutation next to the SSN motif did not exist in these strains. In PBP 2B, the Thr451Ala/Phe/Ser and Glu481Gly mutations close to the SSN motif were observed in 24 strains, which showed penicillin resistance and intermediate resistance, and the Thr624Gly mutation close to the KTG motif was observed in 2 strains for which the imipenem MIC (0.5 microg/ml) was the highest imipenem MIC detected. In PBP 1A, the Thr371Ser/Ala mutation in the STMK motif was observed in all 13 strains for which the penicillin MICs were >/=1 microg/ml. In PBP 2A, the Thr411Ala mutation in the STIK motif was observed in one strain for which with the cefotaxime MIC (8 microg/ml) was the highest cefotaxime MIC detected. On the other hand, in PBPs 1B and 3, no mutations associated with resistance were observed. The results obtained here support the concept that alterations in PBPs 2B, 2X, and 1A are mainly involved in S. pneumoniae resistance to beta-lactam antibiotics. Our findings also suggest that the Thr411Ala mutation in PBP 2A may be associated with beta-lactam resistance.
authors.affiliation: Pharmaceutical Research Department, Meiji Seika Kaisha Ltd., 760 Morooka-cho, Kohoku-ku, Yokohama 222-8567, Japan. takashi_ida@meiji.co.jp
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Sanbongi
authors.forename: Takashi
authors.initials: T
authors.lastname: Ida
authors.forename: Midori
authors.initials: M
authors.lastname: Ishikawa
authors.forename: Yumi
authors.initials: Y
authors.lastname: Osaki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kataoka
authors.forename: Takahisa
authors.initials: T
authors.lastname: Suzuki
authors.forename: Kumiko
authors.initials: K
authors.lastname: Kondo
authors.forename: Fukuichi
authors.initials: F
authors.lastname: Ohsawa
authors.forename: Minoru
authors.initials: M
authors.lastname: Yonezawa
mesh_terms: D019943:Amino Acid Substitution; D019881:Aminoacyltransferases; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics*; D017931:DNA Primers; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics*; D005798:Genes, Bacterial / Q000235:genetics*; D006602:Hexosyltransferases / Q000235:genetics*; D007564:Japan; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D002267:Muramoylpentapeptide Carboxypeptidase / Q000235:genetics*; D009154:Mutation / Q000235:genetics; D046915:Penicillin-Binding Proteins; D010453:Peptide Synthases; D010458:Peptidyl Transferases / Q000235:genetics*; D011008:Pneumococcal Infections / Q000382:microbiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013296:Streptococcus pneumoniae / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D002352:Carrier Proteins; D017931:DNA Primers; D004269:DNA, Bacterial; D046915:Penicillin-Binding Proteins; C478699:penicillin-binding protein 2a, Streptococcus; D019881:Aminoacyltransferases; C478701:penicillin-binding protein 2b, Streptococcus; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D002267:Muramoylpentapeptide Carboxypeptidase; D010453:Peptide Synthases