[Study on PBPs genes of penicillin-resistant Streptococcus pneumonia in Zhejiang province]

To elucidate alternations in gene/amino acid sequence of penicillin-binding proteins (PBPs) 1A, 2B, 2X from clinical isolates of penicillin-resistant Streptococcus pneumonia (PRSP) in Zhejiang Province, 26 strains of Streptococcus pneumonia were collected from November 2001 to January 2004. The antibiotics susceptibility of these strains was detected. PCR amplification and direct sequencing of PBP1A, 2B, 2X genes were performed. The sequence variations of PBP genes of the PRSPs in this region were studied by sequence BLAST analysis. It was shown that the main alternations of PBP1A were the four consecutive amino acid substitutions (Thr574Ala, Ser575Thr, Gln576Gly, Phe577Tyr) following the conservative motif KTG and the amino acid substitution Thr371Ser in the conservative motif STMK. The main alternation of PBP2B was Thr451Ala following the conservative motif SSN, and the main alternation of PBP2X was Thr338Ala in conservative motif STMK. The above mutation sites and drug resistant level were consistent to the data reported previously. Neither new gene mutation specific to these strains nor certain amino acid substitutions related to penicillin resistance reported was identified in the genes.