禽致病性大肠杆菌江苏、安徽分离株的生物学特性分析

Characterization of Avian Pathogenic Escherichia coli isolated from Jiangsu and Anhui provinces

摘要:

【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。

Abstract:

[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 that fimC, 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.