头孢曲松低敏的淋球菌中青霉素结合蛋白2氨基酸替代或插入模式研究

目的 检测头孢曲松低敏的淋球菌中青霉素结合蛋白2（PBP2）模式，探讨其是否与淋球菌对头孢曲松敏感性降低有关。方法 将11株头孢曲松低敏和2株头孢曲松敏感的淋球菌penA基因全基因测序，通过BLASTn与BLASTx分析，研究penA基因的碱基插入和置换情况及PBP2中氨基酸插入和置换模式。结果 13株淋球菌的penA基因中有多个碱基置换或插入，PBP2中共发现5种模式的氨基酸插入或置换模式，没有发现PBP2镶嵌状结构模式。结论 PBP2的镶嵌状结构可能不是导致淋球菌对头孢曲松敏感性下降的主要因素。

Amino acid substitution or insertion patterns in penicillin-binding protein 2 in Neisseria gonorrhoeae isolates with reduced susceptibility to ceftriaxone

Objective To investigate the amino acid patterns in penicillin-binding protein 2(PBP2)in Neisseria gonorrhoeae isolates with reduced susceptibility to ceftriaxonc.and the relationship between the amino acid patterns and reduced ceftriaxone susceptibility.Methods DNA was extracted from 13 clinical isolates of N.gonorrhoeae.including 11 strains with decreased susceptibility to ceftriaxone and 2 sensitive isolates.The full-length penA gene encoding the penicillin-binding protein 2 was amplified and sequenced.BLASTn and BLASTx programs were used to assess the insertion and substitution patterns of nucleotides in penA gene and of amino acids in PBP2,respectively.Results BLASTn analysis revealed insertion or substitution of 18-38 nucleotides in the penA gene of gonococcal isolates with reduced ceftriaxone susceptibility.As shown by BLASTX analysis.there were five patterns of amino acid substitution or insertion in PBP2 of the 11 isolates with reduced ceftriaxone susceptibility.However.mosaic structure of PBP2 was not found in any of these isolates.Conclusion Mosaic PBP2 seems not to be the major factor contributing to the decrease in susceptibility of N.gonorrhoeae to ceftriaxone.