江苏及周边地区鸭致病性大肠杆菌血清型、毒力因子及耐药研究

本研究旨在明确江苏及周边地区鸭禽致病性大肠杆菌（avian pathogenic Escherichia coli，APEC）的血清型、毒力基因分布和耐药性之间的相关性，以期为APEC的防控提供依据。从江苏省及周边养鸭场分离了191株APEC，并对其中21株（每个养殖场选取1株）的O抗原血清型、毒力基因分布和耐药性进行检测。对21株APEC的血清型检测结果表明，O65血清型12株，占全部菌株的57.14%，O5、O28、O42、O87、O93、O138、O147血清型均为1株，其他血清型2株；毒力基因检测结果表明，5个毒力基因有较高的分布率，其中fimA基因的阳性率为100%，ECs3737、ECs3703、tsh和irp2基因的阳性率分别为90.5%、85.7%、57.1%和42.9%，含有5个毒力基因的菌株共有6株（28.57%）；药敏试验结果表明，21株APEC均存在多重耐药性，100%的分离菌株对恩诺沙星、强力霉素、万古霉素和红霉素耐药，85.71%的分离株对10种以上抗生素耐药，14.29%的菌株对21种药物都耐药；对血清型、毒力基因分布和耐药性之间的关系分析表明，含有4种以上毒力基因的菌株有13株，其中9株是O65血清型。在13株含有4种以上毒力基因的菌株中，耐15种药物以上的有9株（69.23%），耐20种以上药物的有3株（23.08%），表明含有4种以上毒力基因的菌株多重耐药现象严重。研究表明，江苏及周边地区鸭源大肠杆菌血清型复杂，携带多种毒力基因，耐药性严重。

Serotypes,Virulence Factors and Antibiotic Resistance of Duck Pathogenic Escherichia coli in Jiangsu Province and Its Surrounding Areas

In this study,191 strains of avian pathogenic Escherichia coli (APEC) were isolated from duck farms in and around Jiangsu province.The serotype,virulence gene distribution and drug resistance of 21 strains (one from each farm) were detected,and the correlation between serotype,virulence gene distribution and drug resistance was analyzed,in order to provide reference for the prevention and control of APEC.The serotypes of 21 APEC strains showed that there were 12 strains of O65,accounting for 57.14% of all strains.The results of virulence gene detection showed that 5 virulence genes had a high distribution rate,among which the positive rate of fimA gene was 100%,and the positive rates of ECs3737,ECs3703,tsh and irp2 genes were 90.5%,85.7%,57.1% and 42.9%,respectively.There were 6 strains (28.57%) with five virulence genes.The results of drug sensitivity test showed that 21 APEC strains had multiple drug resistance,and 100% strains were resistant to enrofloxacin,doxycycline,vancomycin and erythromycin.Among all the strains,85.71% and 14.29% were resistant to more than 10 and 21 kinds of drugs,respectively.The relationship among serotypes,virulence gene distribution and drug resistance showed that there were 13 strains with more than 4 virulence genes,9 of which were O65 serotypes.Among the 13 strains with more than 4 virulence genes,9 strains (69.23%) were resistant to more than 15 drugs,and 3 strains (23.08%) were resistant to more than 20 drugs.The results showed that the serotypes of Escherichia coli isolated from ducks in Jiangsu province and its surrounding areas were complex,carrying a variety of virulence genes,and the drug resistance was serious.