The relationship between penicillin-binding protein genes restriction polymorphism and penicillin susceptibility in Streptococcus pneumoniae / 中华检验医学杂志

ABSTRACT

Objective To indicate the restriction profiles of pbps in Streptococcus pneumoniae(S.pneumoniae), and relationship between pbps profiles and the penicillin MIC.Methods The E-test MIC method was used to determinate penicillin susceptibility of 132 S.pneumoniae strains consisting of 69 penicillin susceptible S.pneumoniae (PSSP) strains and 63 nonsusceptible S.pneumoniae (PNSP) strains. Furthermore, we compared these strains by detecting restriction fragment length polymorphism (RFLP) of the PBPs genes pbp1a, pbp2b and pbp2x.Results The RFLP results showed that 9 genotypes were founded for pbp1a, in which 2 were detected from PSSP and some PNSP strains. The other 7 ones were founded mainly in the PNSP with penicillin MIC≥0.25 ?g/ml. Ten genotypes were founded for pbp2b, in which 3 were detected from PSSP and some PNSP strains. The other 7 ones, similar with pbp1a, were founded mainly in the PNSP with penicillin MIC≥0.25 ?g/ml. Thirty-one restrictive patterns were founded for pbp2x. Seventeen patternss from them were detected in PSSP, and 13 ones were founded only in PSSP. The other 14 patterns all were covered PNSP strains. A total of 47 patterns were found according to the three pbps types. Twenty-three patterns from them were detected in PSSP, and 17 ones were founded only in PSSP. The other 24 patterns all were detected in PNSP.Conclusions Results of the study are consistent with the concept that mutations in PBP1a, PBP2b and PBP2x play an important role in the development of resistance to ?-lactam antibiotics by S.pneumoniae. In the meantime, the profiles of pbps can predict penicillin susceptibility.