Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 4, 1870 Frederiksberg, Denmark.
Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 4, 1870 Frederiksberg, Denmark.
Vet Microbiol. 2013 Mar 23;162(2-4):873-880. doi: 10.1016/j.vetmic.2012.11.008. Epub 2012 Nov 9.
The genetic relatedness and virulence profiles of avian pathogenic Escherichia coli that caused salpingitis and peritonitis in 68 broiler breeders from 21 Danish farms were determined by multilocus sequence typing (MLST), pulsed-field-gel-electrophoresis (PFGE), ECOR phylogrouping, and PCR-based virulotyping. Phylogroups A, B1, B2, and D accounted for 19.1%, 5.9%, 52.9%, and 22.1% of the isolates, respectively. Overall, a total of five main MLST-based clonal groups (3-38 isolates) were identified, comprising 85.3% of the isolates. The most common sequence type (ST) was ST95 (n=12), followed by the ST428-, ST23- and ST350-clonal complexes (CCs) (n=8, n=7 and n=6, respectively). The emerging, antimicrobial resistance-associated clones, ST131 and ST648, were represented by five and three isolates, respectively, whereas ST352 and the ST168 CC comprised four isolates each. Phylogroup-B2 isolates showed a greater prevalence of nine virulence genes (P<0.05). One specific clonal group was significantly associated with phylogroup-B2 isolates (P<0.001), and with isolates that induced secondary septicemia (P=0.001). PFGE analysis revealed 12 clusters of genetically related strains (2-12) sampled from unrelated and geographically distant farms, indicating the widespread distribution and recent vertical transmission of particular APEC lineages. Certain lineages showed more diversity, substantiating that long-term, endemic transmission has been maintained. In conclusion, endemic lineages of E. coli that cause salpingitis and peritonitis in broiler breeders, although diverse, tend to be phylogenetically related, and demonstrate conserved virulence genotypes that might be associated with greater pathogenic potential.
对 68 只来自丹麦 21 个农场的种鸡输卵管炎和腹膜炎的致病性大肠杆菌进行了基因相关性和毒力特征分析，方法是通过多位点序列分型（MLST）、脉冲场凝胶电泳（PFGE）、ECOR phylogrouping 和基于 PCR 的毒力定型。分别有 19.1%、5.9%、52.9%和 22.1%的分离株属于 phylogroups A、B1、B2 和 D。总体而言，共确定了五个主要的基于 MLST 的克隆群（3-38 个分离株），占分离株的 85.3%。最常见的序列型（ST）是 ST95（n=12），其次是 ST428、ST23 和 ST350 克隆群（CC）（n=8、n=7 和 n=6）。新兴的、与抗微生物药物耐药性相关的克隆，ST131 和 ST648，分别由 5 株和 3 株分离株代表，而 ST352 和 ST168 CC 分别由 4 株和 3 株分离株组成。B2 phylogroup 分离株显示 9 种毒力基因的流行率更高（P<0.05）。一个特定的克隆群与 B2 phylogroup 分离株显著相关（P<0.001），与引起继发性败血症的分离株相关（P=0.001）。PFGE 分析显示，从无关联和地理上遥远的农场中采集了 12 个遗传相关菌株的簇（2-12），表明特定的 APEC 谱系广泛分布和近期垂直传播。某些谱系显示出更多的多样性，证实了长期的地方性传播得以维持。总之，引起种鸡输卵管炎和腹膜炎的地方性大肠杆菌谱系虽然多样化，但往往具有系统发育相关性，并表现出保守的毒力基因型，这可能与更大的致病性潜力相关。
