淋病流行株耐药性及耐药基因的定位分析

目的 了解淋病流行株的耐药性，并对其耐药基因进行定位分析。方法 2000～2001年从广东省湛江地区分离到98株淋病流行株，采用K-B法测定淋球菌对10种抗生素的敏感性，应用碱裂解法提取相应菌株的质粒，选择NG4、NG31、NG43、NG70菌株作质粒的接合及消除试验，对耐药基因进行定位。结果 98株淋病流行株对环丙沙星、四环素、氯霉素耐药率分别为82．65％、69．39％、50．00％；质粒总检出率为91．84％，42．5kb、39．5kb、7．4kb、4．2kb质粒分别占11.22％、41.82％、59．16％、67．32％。NG31、NG43能通过接合将对四环素和氯霉素的耐药性传递给受体菌，而通过质粒消除又可恢复对抗生素的敏感性；环丙沙星的耐药性通过接合及消除未见改变。结论 湛江地区淋病流行株耐药形势严峻，耐药基因定位显示，淋球菌对四环素和氯霉素的耐药由质粒介导，对环丙沙星的耐药则由染色体介导。

Study on the location of the resistant gene in gonococcal epidemic strains

Objective To investigate the resistant states of gonococcal epidemic strains and locate their resistant gene.Methods A total of 98 gonococcal strains obtained from 2001 to 2002 in Zhanjiang were identified systemically.The susceptibilities of 98 strains of gonococci to 10 kinds of antibiotics were detected by K B method.The plasmids were extracted by alkaline lysis technique.The strains of NG4,NG31,NG43 and NG70 were selected to locate the resistant gene through the conjugation and curing of plasmids.Results The resistant percentages of gonococcal epidemic strains to ciprofloxacin,tetracycline and chloramphenicol were 82.65%,69.39% and 50%,respectively.The percentage of plasmid accounted for 91.84%;among them,the percentages of 42.5kb,39.5kb,7.4kb and 4.2kb plasmids were 11.22%,41.82%,59.16% and 67.32%,respectively.The resistance of NG31 and NG43 to tetracycline and chloramphenicol could be transferred through conjugation to the sensitive gonococcus standard strain and E.coli C600,and their susceptibilities could be restored through the curing of plasmids.There was no change for the resistance of gonococci to ciprofloxacin through conjugation and curing.Conclusion The resistant states of N.gonorrhoeae to antibiotics are serious in Zhanjiang.The location of the resistant gene suggests that the resistance of gonococci to tetracycline and chloramphenicol might be mediated by plasmids,and that to ciprofloxacin mediated by chromosomes.