Horizontal spread of an altered penicillin-binding protein 2B gene between Streptococcus pneumoniae and Streptococcus oralis

The region encoding the transpeptidase domain of the penicillin-binding protein 2B (PBP 2B) gene of two penicillin-resistant clinical isolates of Streptococcus oralis</it> was > 99.6% identical in nucleotide sequence to that of a penicillin-resistant serotype 6 isolate of Streptococcus pneumoniae</it>. The downstream 849 base pairs of these genes were identical. Analysis of the data indicates that the PBP gene has probably been transferred from S. pneumoniae</it> into S. oralis</it>, rather than vice versa, and shows that one region of this resistance gene has been distributed horizontally both within S. pneumoniae</it> and into two different viridans group streptococci.