山东省O139群霍乱弧菌的分子特征及耐药性研究

Molecular characteristics and antibiotic resistance of Vibrio cholerae O139 in Shandong province

目的 调查山东省O139群霍乱弧菌分子流行病学特征及耐药谱.方法 对山东省自1997年O139群霍乱疫情出现以来分离的13株O139群霍乱弧菌（9株为临床分离株,4株为环境株）进行生化鉴定及血清型复核,同时进行PFGE分子分型和毒力基因及耐药相关基因检测,使用微量肉汤稀释法检测其耐药性.结果 山东省13株O139群霍乱弧菌聚类为7个PFGE型别,其中2013年济宁的1株临床株和2株环境株聚为KZGN11O139.CN0077,2005年济南的1株临床株、2005年济宁的1株临床株和2009年菏泽的临床株聚为KZGN11O139.CN0002,其余均各自为不同的型别.2株烟台临床株缺失ctxAB和tcpI基因,PFGE条带也较为特殊,其他11株霍乱弧菌均含有hlyA、ctxAB、toxR、tcpI、rtx和tcpA6种毒力基因.13株霍乱弧菌均含有耐药相关基因intI1、intI4及sxt.在12种抗生素中,卡那霉素、复方磺胺甲恶唑、氨苄西林及庆大霉素的耐药率分别为11/13、9/13、7/13和7/13.结论 山东省O139群霍乱弧菌PEGE分型提示菌株间可能存在流行病学关联,多数菌株产毒且耐药.

Objective To investigate the molecular epidemiological characteristics and antibiotic resistance profiles of Vibrio cholerae O139 in Shandong province. Methods A total of 13 strains of V. cholerae O139 （9 clinical strains and 4 environmental strains ） isolated from cholera epidemics in Shandong province since 1997 were recovered and confirmed with serum agglutination and biochemical reaction. Pulsed-field gel electrophoresis （PFGE） was carried out for molecular subtyping. Virulence genes and drug resistance related genes were detected by PCR. Antibiotic susceptibility tests were performed using micro-broth dilution method. Results Thirteen strains of V. cholerae O139 were differentiated into seven pulsetypes. One clinical strain and two environmental strains isolated from Jining in 2013 were clustered into the pulsetype namely KZGN11 O139. CN0077, and an identical PFGE pattern of KZGN11 O139. CN0002 was found among three clinical strains from Jinan in 2005, Jining in 2005 and Heze in 2009. Other pulsotypes were unique in China and found only in Shandong province. Because of deletion of ctxAB and tcpl, the PFGE patterns of two strains isolated from Yantai in 2000 and 2004 were different from other 11 strains which harbored ctxAB,tcpA, tcpl, rtxA, hlyA and toxR. All strains contained one or more drug resistance related genes such as intI 1, intI 4 and sxt, and were resistant to two kinds of antibiotics at least. Among the 12 kinds of antibiotics, the resistant ratioes to kamamycin, trimethoprim-sulfamethoxazole, ampicillin and gentamicin were 11/13, 9/13, 7/13 and 7/13, respectively. Conclusion Molecular subtyping indicates possible epidemiological links among V. cholerae O139 in Shandong province, and almost all strains were toxigenic and drug resistant.