摘要
目的通过连续3年监测成都周边某奶牛养殖场犊牛和成年牛粪便、饲养环境及菜市场和超市生鲜牛肉中的产志贺毒素大肠埃希菌(STEC),了解本地区牛及牛肉中STEC菌株的携带及菌株特征情况,为评估该地区STEC污染状况、感染风险及防控策略提供科学依据。方法采用荧光定量PCR法分离鉴定STEC,采用微量肉汤稀释法进行药敏试验。分离株全基因组测序后在EnteroBase数据库上获得MLST型别、菌株类型、血清型、毒力基因信息,使用Abricate软件比对得到stx亚型信息。用BioNumerics 7.6软件进行cgMLST聚类分析。结果2019—2021年共采集奶牛养殖场牛粪和环境样品247份,25份检出STEC,检出率10.12%;采集生鲜牛肉294份,32份检出STEC,检出率10.88%;共分离到57株STEC。检出STEC菌株对氨苄西林耐药率最高,达42.11%(24/57),其次为头孢噻肟和头孢唑啉(均占比38.60%,22/57)。多重耐药株占35.09%(20/57)。57株STEC共分离出30种血清型,其中可引起暴发的血清型有:O26:H11、O103:H25、O145:H12。通过毒力基因分析发现具有致病风险的亚型有:stx2a、stx2c、stx2d、stx2e、stx2g以及stx2k;及与疾病的严重程度密切相关eae-STEC及STEC/ETEC杂合株。结论2019—2021年奶牛养殖场牛粪便和菜市场生鲜牛肉中STEC的污染持续存在。犊牛粪便检出率(21.43%)高于成年牛粪便检出率(0.91%)。菜市场生鲜牛肉STEC检出率高于超市。牛粪便中分离菌株比牛肉中分离菌株耐药情况严重。部分分离菌株因携带强毒力基因或其他致病相关基因而具有更强致病性。
Objective To understand the carrying status and strain characteristics of STEC strains in cattle and beef in the local area,provide scientific basis for evaluating the STEC pollution status,infection risk,prevention and control strategies in the region,the Shiga toxin producing Escherichia coli(STEC)in the feces of calves and adult cows and feeding environment in a dairy farm around Chengdu,as well as fresh beef from vegetable markets and supermarkets for three years were continuously monitored.Methods STEC using fluorescence quantitative PCR method was identified,and drug sensitivity testing using micro broth dilution method was conducted.After sequencing the entire genome of the isolated strain,the MLST type,strain type,serotyping,and virulence gene information were obtained on the EnteroBase database.The stx subtype information was compared using the Abricate software.Perform cgMLST clustering analysis was used by BioNumerics 7.6 software.Results From 2019 to 2021,a total of 247 cow manure and environmental samples were collected from dairy farms,and 25 STEC strains were isolated,with a detection rate of 10.12%.294 fresh beef samples were collected and 32 STECs were isolated,with a detection rate of 10.88%.A total of 57 STEC strains were isolated.The STEC strain had the highest resistance rate to ampicillin,reaching 42.11%(24/57),followed by cefotaxime and cefazolin at 38.60%(22/57).Multiple resistant strains accounted for 35.09%(20/57).A total of 30 serotypes were isolated from 57 STEC strains,among which the serotypes that can cause outbreaks include O26:H11,O103:H25,and O145:H12.Through virulence gene analysis,it was found that subtypes with pathogenic risk included stx2a,stx2c,stx2d,stx2e,stx2g,stx2k,as well as eae-STEC and STEC/ETEC heterozygous strains.Conclusion The pollution of STEC in cow manure from dairy farms and fresh beef from vegetable markets continued to exist from 2019 to 2021.The detection rate of calf feces was 21.43%,which was higher than that of adult cow feces by 0.91%.The STEC detection rate of fresh beef in vegetable markets is significantly higher than that in supermarkets.The drug resistance of strains isolated from cow manure is more severe than that of strains isolated from beef.Some isolated strains have stronger pathogenicity due to carrying strong virulence genes or other pathogenic related genes.
作者
吕虹
雷高鹏
刘丽
肖桃
杨小蓉
LYU Hong;LEI Gaopeng;LIU Li;XIAO Tao;YANG Xiaorong(Sichuan Center for Disease Control and Prevention,Sichuan Chengdu 610041,China)
出处
《中国食品卫生杂志》
CSCD
北大核心
2023年第12期1727-1733,共7页
Chinese Journal of Food Hygiene
基金
四川省科技厅2022年度重大科技专项(2022ZDZX0017)
关键词
产志贺毒素大肠埃希菌
耐药
血清型
毒力基因
Shiga toxin producing Escherichia coli
drug resistance
serotype
virulence gene
