Diversity of mosaic pbp2x families of penicillin-resistant Streptococcus pneumoniae from Iran and Romania [PublishAheadOfPrint]

High rates of penicillin-resistant Streptococcus pneumoniae occur in Romania and the Iran. The mosaic structure of PBP2x was investigated in nine Iranian strains and in 15 strains from Romania to understand their evolutionary history. Mutations potentially important for β-lactam resistance were identified by comparison with related PBP2x of penicillin-sensitive reference S. mitis strains. Two main PBP2x mosaic gene families were recognized. Eight Iranian strains belonged to group 1 PBP2x with a mosaic block highly related to PBP2x of the clone Spain^23F-1 which is widespread among international penicillin-resistant S. pneumoniae clones. A second unique PBP2x group was observed in Romanian strains; furthermore, three PBP2x represented single mosaic variants. Sequence blocks of the penicillin-sensitive S. mitis 658 were common among PBP2x of strains from both countries. Each PBP2x group contained specific signature mutations within the transpeptidase domain, documenting distinct mutational pathways for the development of penicillin resistance.

http://ift.tt/2fFXGfL