OBJECTIVETo identify the relationship between amino acid mutations in Neisseria gonorrhoeae isolates and their antibiotic resistance.

METHODSPI gene fragments of Neisseria gonorrhoeae from 17 clinical isolates were obtained with PCR amplification. They were cloned into the PCR cloning vector pBS-T to form pBS-T-PI and sequenced. The sequences of PI genes were analyzed. At the same time, minimum inhibitory concentration (MIC) of penicillin and tetracycline to these 17 isolates were measured and contrasted with the corresponding PI sequence.

RESULTSThe recombinants of PI gene from 17 clinical isolates of Neisseria gonorrhoeae were successfully constructed and sequenced. They were divided into PIA and PIB subtypes according to the results from blastn software by comparing the sequences with the GenBank. Mutations were found at the sites of 120 and 121. There were only some of the sequences having an aspartic acid (D) mutation on 120 and 121 sites, which was not the same as reported. On the other hand,there were two PI sequences,5-9 and 6-1, whose mutations on No. 120 were lysine, similar to those documented.

CONCLUSIONSome relationship between PI amino acids mutations at sites 120 and 121 in Neisseria gonorrhoeae isolates from Chengdu, China and their resistance to penicillin and tetracycline were found. However,further studies need to be done in the future to confirm this hypothesis.