[Objective] The aim of this study was to study the main serotypes and the biological characteristics of Avian Pathogenic Escherichia coli (APEC) isolated from Jiangsu and Anhui provinces.[Methods] The tested strains were isolated from sick poultry and identified by slide agglutination to determine serotypes.Virulence-associated genes were identified by PCR and the drug susceptibilities were detected according to Clinical and Laboratory Standards Institute (CLSI).Moreover,the biofilm-forming abilities were detected through improved crystal violet semi-quantitative method.[Results] In total 56 strains were isolated and identified.Slide agglutination results show that O78 was the main serotype accounted for 64.29％ of the isolates.PCR amplification results of the virulence-associated genes showed thatfimC,pfs,ompA and luxS were amplified from more than 90％ of the tested strains.Drug sensitivity test results showed that 58.93％ of the strains were resistant to more than 8 antibiotics.Biofilm formation assay showed that 16 isolates produced moderate or strong biofilm in vitro,in which 68.75％ were resistant to more than 8 antibiotics.[Conclusion] O78 was the main serotype among the isolates.The genes of fimC,pfs,ompA and luxS were conserved in APEC.Multi-antibiotic resistance was very common and drug resistance seemed relative to biofilm-forming ability.%[目的]研究禽致病性大肠杆菌(Avian Pathogenic Escherichia coli,APEC)江苏、安徽分离株的优势血清型,并分析其生物学特性.[方法]对分离自病禽的细菌进行鉴定,采用玻片凝集法测定禽致病性大肠杆菌的血清型,PCR方法检测14种毒力基因的分布,采用美国临床和实验室标准化研究所的方法进行药物敏感性检测,改良结晶紫半定量法检测分离细菌的生物被膜形成能力. [结果]共分离到禽致病性大肠杆菌56株,血清型检测结果表明,O78血清型占64.29％,为主要血清型.毒力基因检测显示,fimC、pfs、ompA和luxS的阳性率超过90％.药物敏感性检测显示,58.93％的菌株对8种以上的药物耐受.生物被膜检测显示,有16株细菌生物被膜形成能力为中等以上,其中68.75％的菌株耐8种以上的药物.[结论]O78为主要流行的血清型.fimC、pfs、ompA和luxS基因为APEC保守基因.多重耐药性仍很普遍,细菌生物被膜与耐药性具有相关性.
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