| 摘要: |
| 为查明南京市某赛鸽公棚赛鸽出现腹泻、死亡的致病病原，本研究对采集的病料进行病原分离鉴定，分析致病菌的血清型、生物被膜表型、毒力基因、耐药菌谱，并对分离菌株进行了人工感染试验。研究表明:1)从患病鸽组织、拭子和粪便中分离出的细菌初步诊断为大肠杆菌O157；分离菌株在NA平板上长出白色、光滑的圆形菌落，在CT-SMAC平板上长出紫红色菌落。2)分离菌株的16S rRNA基因序列与大肠杆菌的相似性达98%~99%，命名为E.c.86246。3)血清学试验表明分离菌株为大肠杆菌O157:非H7菌株，动力试验进一步证实其为动力株。4)分离菌株携带tccp1014、eaeA和hly毒力基因，可导致雏鸡胃肠道出现不同程度的功能损伤，甚至导致死亡；其半数致死量为2.0×105 CFU/mL，具有较强的致病性。5)分离菌株携带tetA、tetM、sul2、aadA1和blaTEM 5种耐药基因，具有较弱的生物被膜形成能力，对四环素、氨基糖苷类等抗菌药物严重耐药，对阿莫西林、氧氟沙星和诺氟沙星敏感。综上，本研究分离的鸽源大肠杆菌O157:非H7菌株，具有动力性，有较强的致病性和一定的耐药性，为大肠杆菌O157的流行病学调查、致病机理分析和抗菌药物的精准施治提供理论依据和数据参考。 |
| 关键词: 鸽 大肠杆菌O157 血清型 生物被膜 致病性 耐药性 |
| DOI：10.11841/j.issn.1007-4333.2023.06.16 |
| 投稿时间：2022-08-07 |
| 基金项目:国家科技部“十四五”重点研发项目(2021YFD1800405)；国家自然科学基金面上项目(31520103917) |
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| Pathogenicity and drug resistance isolation, identification and biological characteristics of pigeon derived Escherichia coli O157:non H7 strain |
|
YANG Wenyi1,XIAO Jiawei1,LEI Liancheng1,2*,ZHANG Fuxian1*
|
| (1. College of Animal Science, Yangtze University, Jingzhou 434023, China;2. College of Veterinary Medicine, Jilin University, Changchun 130062, China) |
| Abstract: |
| In order toidentity the pathogenic bacteria causing diarrhea and death of a racing pigeon in Nanjing, in the study, the pathogen from collected diseased materials were isolated and identified, the serotype, biofilm phenotype, virulence gene, and drug resistance spectrum of the pathogenic bacteria were analyzed, and artificial infection tests on the isolated strains were conducted. The results showed that: 1)The bacteria isolated from diseased pigeon tissues, swabs and feces were initially diagnosed as E. coli O157 in the laboratory. The isolated strains grew white and smooth round colonies on the NA plate and purple red colonies on the CT-SMAC plate. 2)The 16S rRNA gene sequence of the isolated strain was 98%-99% similar to that of Escherichia coli, and was named E. c. 86246. 3)The serological test showed that the isolated strain was Escherichia coli O157: non H7 strain, and the kinetic test further confirmed that it was a dynamic strain. 4)The isolated strain carriying tccp1014, eaeA and hly virulence genes can cause varying degrees of functional damage to the gastrointestinal tract of chicks, and even lead to death. Its median lethal dose was 2. 0×105 CFU/mL, with strong pathogenicity. 5)The isolated strain carries tetA, tetM, sul2, aadA1 and blaTEM resistance genes, had weak biofilm formation ability, and were severely resistant to tetracycline, aminoglycosides and other antimicrobial drugs, and were sensitive to amoxicillin, ofloxacin and norfloxacin. To sum up, the pigeon derived Escherichia coli O157: non H7 strain isolated in this study is mobile strain, has strong pathogenicity and certain drug resistance. The results provide theoretical basis and data reference for the epidemiological investigation, pathogenic mechanism analysis and precise treatment of antimicrobial drugs of Escherichia coli O157. |
| Key words: pigeon Escherichia coli O157 serotype biofilm pathogenicity antimicrobial resistance |
