Directly repeated insertion of 9-nucleotide sequence detected in penicillin-binding protein 2B gene of penicillin-resistant Streptococcus pneumoniae

Abstract

We investigated the molecular mechanism of 50 penicillin-resistant Streptococcus pneumoniae strains (penicillin: MIC, ≥0.125 μg/ml) having neither class A nor class B mutations in the penicillin-binding protein 2B gene (pbp2b). An analysis of the nucleotide sequences of the pbp2b genes from seven strains revealed an unique direct repeat of 9 nucleotides (TGGTATACT) between active-site serine (residue 385) and Ser-X-Asn (residues 442 to 444) motifs. The same insertion was detected in 13 strains.