吉林省规模化猪场断奶仔猪大肠杆菌分离鉴定与耐药表型及耐药基因检测

Isolation,identification,drug resistance phenotype and drug resistance gene detection of Escherichia coli of weaned piglets from large-scale pig farms in Jilin Province

为了解"禁抗"前吉林省不同地区规模化生猪养殖场耐药现状以及耐药基因存在情况,本研究对吉林省20个市(县)35个规模化生猪养殖场断奶仔猪的粪便样本进行大肠杆菌分离鉴定、药物敏感性测定以及耐药基因检测,共采集粪便样本1144份(994份腹泻粪便样本,150份健康粪便样本),通过平板划线、16S rRNA测序以及生化鉴定,共分离到892株大肠杆菌,总分离率为77.97%。药物敏感性测定结果表明,大肠杆菌分离株存在严重的多重耐药性,其中对β-内酰胺类、大环内酯类、四环素类、磺胺类、氨基糖苷类、喹诺酮类以及氯霉素类抗生素耐药率较高。相比之下,大肠杆菌分离株对头孢类和多磷类抗生素耐药率较低,未发现多黏菌素耐药菌株。对不同猪场的175株大肠杆菌分离株进行耐药基因检测,共检出15种耐药基因,bla;(30.85%)、floR(57.14%)、aac(3)-Ⅰb(36.57%)、ant(3)-Ⅰa(66.28%)、aac(3)-Ⅱb(40.57%)、sulⅠ(37.71%)以及aac(6)-Ⅰb(41.71%)检出率较高。其中,含有2类以上抗生素耐药基因的大肠杆菌比例高达82.28%(144/175)。本研究结果表明,吉林省猪场大肠杆菌存在严重的多重耐药性,并携带多种耐药基因,为临床用药、进一步研究大肠杆菌耐药分子机制以及"禁抗"前了解吉林省大肠杆菌耐药情况提供依据。

In order to understand the current status of drug resistance and the existence of drug resistance genes in weaned piglets from large-scale pig farms in different regions of Jilin Province before antibiotics were banned.In this study,fecal samples of weaned piglets from 35 large-scale pig farms in 20 cities(county)of Jilin Province were subjected to E.coli isolation,identification,drug susceptibility testing,and drug resistance gene testing.A total of 1144 stool samples were collected(994 diarrhea stool samples and 150 healthy stool samples).Through plate streaking,16 S rRNA sequencing and biochemical identification methods,a total of 892 strains of E.coli were isolated,with a total isolation rate of 77.97%.The results of drug sensitivity test showed that the isolates of E.coli had severe multiple drug resistance,and they showed high drug resistance rate toβ-lactam,macrolides,tetracycline,sulfonamides,aminoglycosides,quinolones and chloramphenicol antibiotics.In contrast,E.coli isolates showed lower resistance to cephalosporins and polyphosphor antibiotics.Moreover,no polymyxin resistant strains were found.The detection of drug resistance genes on 175 strains of E.coli isolates from different pig farms showed that a total of 15 drug resistance genes were detected,the genes of blaTEM(30.85%),floR(57.14%),aac(3)-Ⅰb(36.57%),ant(3)-Ⅰa(66.28%),aac(3)-Ⅱb(40.57%),sulⅠ(37.71%)and aac(6)-Ⅰb(41.71%)have higher detection rates.Among them,the proportion of E.coli isolates containing more than two classes of antibiotic resistance genes reached 82.28%(144/175).The results of this study showed that E.coli from large-scale pig farms in Jilin Province had severe multi-drug resistance and carried multiple drug-resistant genes,but no polymyxin-resistant strains had been found,which provided a basis for clinical drug use,further research on the molecular mechanism of drug resistance of E.coli and the drug resistance situation of E.coli in Jilin Province before"anti-resistance prohibition".