School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia.
Vet Microbiol. 2012 Jan 27;154(3-4):305-15. doi: 10.1016/j.vetmic.2011.07.010. Epub 2011 Jul 21.
Antibiotic use in poultry production is a risk factor for promoting the emergence of resistant Escherichia coli. To ascertain differences in different classes of chickens, the resistance profile, some virulence genes and phylogenetic grouping on 251 E. coli isolates from intensive meat (free range and indoor commercial) and free range egg layer chickens collected between December 2008 and June 2009 in South Australia were performed. Among the 251 strains, 102 (40.6%) and 67 (26.7%) were found to be resistant to tetracycline and ampicillin respectively. Resistance was also observed to trimethoprim-sulfamethoxazole (12.4%), streptomycin (10.8%), spectinomycin (9.6%), neomycin (6.0%) and florfenicol (2.0%) but no resistance was found to ceftiofur, ciprofloxacin or gentamicin. Amplification of DNA of the isolates by polymerase chain reaction revealed the presence of genes that code for resistant determinants: tetracycline (tet(A), tet(B) and tet(C)), ampicillin (bla(TEM) and bla(SHV)), trimethoprim (dhfrV and dhfrXIII), sulphonamide (sulI and sulII), neomycin (aph(3)-Ia(aphA1)), and spectinomycin-streptinomycin (aadA2). In addition, 32.3-39.4% of the isolates were found to belong to commensal groups (A and B1) and 11.2-17.1% belonged to the virulent groups (B2 and D). Among the 251 E. coli isolates, 25 (10.0%) carried two or more virulence genes typical of Extraintestinal pathogenic E. coli (ExPEC). Furthermore, 17 of the isolates with multi-resistance were identified to be groups B2 and D. Although no significant difference was observed between isolates from free range and indoor commercial meat chickens (P>0.05), significant differences was observed between the different classes of meat chickens (free range and indoor commercial) and egg layers (P<0.05). While this study assessed the presence of a limited number of virulence genes, our study re emphasises the zoonotic potential of poultry E. coli isolates.
在禽类养殖中使用抗生素是促进耐药大肠杆菌出现的一个风险因素。为了确定不同种类鸡之间的差异，对 2008 年 12 月至 2009 年 6 月期间在南澳大利亚收集的 251 株来自集约化肉用（放养和室内商业）和自由放养蛋鸡的大肠杆菌分离株进行了耐药谱、部分毒力基因和系统发育分组分析。在 251 株菌株中，分别有 102（40.6%）和 67（26.7%）株对四环素和氨苄西林耐药。还观察到对甲氧苄啶-磺胺甲恶唑（12.4%）、链霉素（10.8%）、壮观霉素（9.6%）、新霉素（6.0%）和氟苯尼考（2.0%）耐药，但对头孢噻呋、环丙沙星或庆大霉素耐药。聚合酶链反应扩增分离株的 DNA 显示存在编码耐药决定因素的基因：四环素（tet(A)、tet(B)和 tet(C)）、氨苄西林（bla(TEM)和 bla(SHV)）、甲氧苄啶（dhfrV 和 dhfrXIII）、磺胺类（sulI 和 sulII）、新霉素（aph(3)-Ia(aphA1)）和壮观霉素-链霉素（aadA2）。此外，32.3-39.4%的分离株属于共生群（A 和 B1），11.2-17.1%属于毒力群（B2 和 D）。在 251 株大肠杆菌分离株中，有 25（10.0%）株携带两种或两种以上与肠外致病性大肠杆菌（ExPEC）相关的毒力基因。此外，17 株多耐药分离株被鉴定为 B2 和 D 群。虽然放养和室内商业肉用鸡分离株之间没有观察到显著差异（P>0.05），但不同种类的肉用鸡（放养和室内商业）和蛋鸡之间存在显著差异（P<0.05）。虽然本研究评估了有限数量的毒力基因的存在，但本研究再次强调了家禽大肠杆菌分离株的人畜共患病潜力。
