辽宁省阜新市副溶血性弧菌的生物学特征、毒力基因、耐药特征及分子溯源

目的 了解2016—2020年辽宁省阜新市副溶血性弧菌的生物学特征、毒力基因、耐药特征及MLST分型情况。方法 对2016—2020年分离到的42株副溶血性弧菌,采用PCR方法扩增其毒力基因和7个管家基因,PCR扩增测序后采用DNAstar和Bioedit等软件,对本次研究的42株副溶血弧菌进行MLST同源性分析。采用Kirby-Bauer纸片法检测抗生素的耐药性。结果 42株副溶血性弧菌均扩增出tlh基因,临床株以tlh+tdh+VPaI-1+VPaI-7+T3SS1+T3SS2+毒力基因型为主（53.8%,7/13）,而食品株以仅含有tlh+毒力基因型为主（37.9%,11/29）,13株临床株中均含有tdh或/和trh,仅有1株临床株为tdh和trh双阳性。42株菌共分为 22种ST型,其中ST3型10株,本研究中的42株菌株,PHYLOViZ软件分析显示是以ST345型副溶血性弧菌为起源,形成ST162、ST1413和ST2 3个克隆群。菌株对氨苄西林和青霉素100.0%耐药,对头孢呋辛、羧苄西林和多西四环素的耐药率分别达到88.0%、83.3%和81.0%,对庆大霉素和头孢哌酮的敏感性较高,耐药率分别为21.4%和35.7%。结论 本研究表明,阜新市存在较为严重的副溶血性弧菌污染,临床株携带的副溶血性弧菌毒力基因多于食品株,且对抗生素存在较为严重的耐药性,提示应加强副溶血性弧菌的病原学和分子流行病学监测,需重视流通环节海产品的监督管理,防止食物中毒事件发生。

Biological characteristics,virulence genes,drug resistance characteristics and molecular traceability analysis of Vibrio parahaemolyticus in Fuxin,Liaoning

Objective To understand the biological characteristics, virulence genes, drug resistance and MLST typing of Vibrio parahaemolyticus in Fuxin from 2016 to 2020. Methods The virulence genes and 7 housekeeping genes of 42 strains of Vibrio parahaemolyticus isolated from 2016 to 2020 were amplified by PCR. After PCR amplification and sequencing, the MLST homology of 42 strains of Vibrio parahaemolyticus was analyzed by DNAStar and Bioedit software. Kirby-Bauer disk method was used to detect antibiotic resistance. Results Tlh gene was amplified in all 42 strains of Vibrio parahaemolyticus. Tlh + tdh + VPaI-1 + VPaI-7 + T3SS1 + T3SS2 + virulence genotype was dominant in clinical strains (53.8%, 7/13), while tlh + virulence genotype was dominant in food strains (37.9%, 11/29). Tdh or/ and trh were found in all 13 clinical strains, and only one clinical strain was double positive for tdh and trh. The 42 strains were divided into 22 ST types, including 10 ST3 strains. PHYLOViZ software analysis showed that the 42 strains in this study originated from Vibrio parahaemolyticus ST345 and formed three clone groups ST162, ST1413 and ST2. The strains were 100.0% resistant to ampicillin and penicillin. The resistance rates to cefuroxime, carbenicillin and doxytetracycline were 88.0%, 83.3% and 81.0%, respectively. The strains were highly sensitive to gentamicin and cefoperazone, and the resistance rates were 21.4% and 35.7%, respectively. Conclusion This study shows that Vibrio parahaemolyticus is seriously polluted in Fuxin area, the virulence genes of clinical strains are more than those of food strains, and there is a serious resistance to antibiotics. It suggested that we should pay attention to the supervision and management of marine products in circulation to strengthen the etiology and molecular epidemiology monitoring of Vibrio parahaemolyticus, prevent food poisoning.