辽宁省婴幼儿食品中肠集聚性大肠埃希菌的病原学特征及耐药谱研究

Pathogenic characteristics and drug resistance spectrum of Enteroaggregative Escherichia coli in infant food in Liaoning Province from 2018 to 2020

目的对2018—2020年辽宁省婴幼儿食品中致泻大肠埃希菌开展持续监测,了解和掌握本省内致泻大肠埃希菌的病原学特征、药物敏感性特征,为本省致泻大肠埃希菌流行病学研究奠定坚实基础,为可能导致的食源性疾病合理用药提供依据。方法采集辽宁省共208份婴幼儿食品,分离肠杆菌科细菌,并进行16S rRNA基因测序分析与生化鉴定。对鉴定得到的大肠埃希菌进行毒力基因检测,收集分离的肠集聚性大肠埃希菌(EAEC)进一步进行血清学分型和耐药谱研究。结果16S rRNA基因测序通过对肠杆菌科进行种鉴定,发现与生化结果一致。其中EAEC的检出率较高,且EAEC的毒力基因pic携带率高。毒力基因分型和血清分型具有一致性。共检测出25株EAEC,其中40%菌株(血清型O134:H9)携带毒力基因pic,28%菌株(血清型O3:H2)同时携带毒力基因aggR和astA,16%菌株(血清型O9:H6)携带毒力基因aggR,16%菌株(血清型O62:H7)携带毒力基因astA。78株大肠埃希菌中EAEC毒力基因的携带率为32.1%。25株EAEC为多重耐药株,主要对β内酰胺类、大环内酯类、喹诺酮类、四环素类抗菌药物耐药严重。结论EAEC是辽宁省婴幼儿食品中大肠埃希菌主要污染菌型,且具有较高的耐药性,应给予更多关注。

Objective To give a solid foundation for the epidemiological data of diarrheagenic Escherichia coli(DEC),and provide a basis for the rational drug use for foodborne diseases caused by DEC,the continuous monitoring of DEC from 2018 to 2020 in Liaoning Province was carried out.The pathogenic characteristics and drug sensitivity characteristics of DEC were investigated.Methods A total of 208 infant food in Liaoning Province were collected,from which Enterobacteriaceae was isolated,and 16S rRNA gene sequencing analysis and biochemical identification were carried out.The virulence genes of E.coli were detected.The serotype and drug resistance spectrum of EAEC were identified.Results Identified species of Enterobacteriaceae by 16S rRNA gene sequencing method was consistent with the biochemical results.The detection rate of EAEC in infant food was high,and the detection rate of virulence gene pic of EAEC was high.Virulence genotyping was consistent with the serum typing.According to the virulence gene carried by Escherichia coli,25 strains of EAEC were detected,of which 40%of the strains(serotype O134:H9)carried virulence gene pic,28%of the strains(serotype O3:H2)carried virulence gene aggR and astA,16%of the strains(serotype O9:H6)carried virulence gene aggR,and 16%of the strains(serotype O62:H7)carried virulence gene astA.The carrying rate of EAEC virulence gene in 78 strains was 32.1%.The drug resistance of 25 EAEC strains was not optimistic,and there were multiple drug-resistant strains.The resistance was mainly forβlactams,macrolides,quinolones and tetracyclines.Conclusion EAEC was the main contamination of Escherichia coli in infant food in Liaoning Province,and had high drug resistance,which need more attention to be paid to.