Ngeleka Musangu, Brereton Lena, Brown Gabriel, Fairbrother John M
Prairie Diagnostic Services and Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, Canada.
Avian Dis. 2002 Jan-Mar;46(1):143-52. doi: 10.1637/0005-2086(2002)046[0143:POAECA]2.0.CO;2.
One hundred four Escherichia coli isolates were collected from internal tissues and the cloacae of broilers with colibacillosis or from the cloacae of healthy birds. The isolates were tested for the presence of DNA sequences for temperature-sensitive hemagglutinin (tsh), for P (pap) and F1 (pil) fimbriae, and for aerobactin synthesis (iuc) by DNA/DNA hybridization. The isolates were also tested for O1, O2, and O78 serogroups, serum and antibiotic resistance, and virulence in day-old chickens. The Tsh/Pil/Iuc was the major pathotype detected in 53.8% of isolates from internal tissues, as compared with only 28.8% of isolates from the cloacae. The Tsh/Pap/Iuc pathotype was detected at a lower frequency (15.4%) but only in isolates from internal tissues. Among the virulence-associated marker genes, tsh and iuc were detected in most of the isolates from internal tissues (90.4% and 92.3%), as compared with only 51.9% and 63.5% of isolates from the cloacae, respectively, pap was detected to a lesser extent, in 25% of isolates but only from internal tissues. In contrast to the pil gene, the tsh-, pap-, and iuc-DNA sequences were more frequently detected in isolates from internal tissues than in isolates from the cloacae. O-antigen typing revealed that 25% of isolates belonged to serogroups O1 (4.8%), O2 (9.6%), and O78 (10.6%). Although most isolates appeared to be resistant to serum, only isolates from internal tissues were virulent in day-old chickens in contrast to isolates from the cloacae. More than 10% of isolates were resistant to most of the antibiotics used for the study. However, less resistance to enrofloxacin and norfloxacin was observed. Our data suggest that the Tsh/Pil/Iuc and Tsh/Pap/Iuc pathotypes and Tsh and Iuc virulence-associated markers are important factors of avian pathogenic E. coli. Enrofloxacin appeared to be the best choice for treatment of the infection.
从患有大肠杆菌病的肉鸡内部组织和泄殖腔或健康鸡的泄殖腔中收集了104株大肠杆菌分离株。通过DNA/DNA杂交检测这些分离株中是否存在温度敏感血凝素（tsh）、P（pap）和F1（pil）菌毛的DNA序列以及气杆菌素合成（iuc）相关序列。还对这些分离株进行了O1、O2和O78血清群、血清和抗生素抗性以及对一日龄雏鸡的毒力检测。Tsh/Pil/Iuc是在53.8%的内部组织分离株中检测到的主要致病型，相比之下，泄殖腔分离株中只有28.8%为该致病型。Tsh/Pap/Iuc致病型的检测频率较低（15.4%），但仅在内部组织分离株中检测到。在与毒力相关的标记基因中，大多数内部组织分离株（90.4%和92.3%）检测到tsh和iuc，相比之下，泄殖腔分离株中分别只有51.9%和63.5%检测到，pap检测到的程度较低，仅在25%的内部组织分离株中检测到。与pil基因不同，tsh、pap和iuc的DNA序列在内部组织分离株中比在泄殖腔分离株中更频繁地被检测到。O抗原分型显示，25%的分离株属于O1（4.8%）、O2（9.6%）和O78（10.6%）血清群。虽然大多数分离株似乎对血清有抗性，但与泄殖腔分离株相比，只有内部组织分离株对一日龄雏鸡具有毒力。超过10%的分离株对本研究中使用的大多数抗生素有抗性。然而，观察到对恩诺沙星和诺氟沙星的抗性较低。我们的数据表明，Tsh/Pil/Iuc和Tsh/Pap/Iuc致病型以及Tsh和Iuc毒力相关标记是禽致病性大肠杆菌的重要因素。恩诺沙星似乎是治疗该感染的最佳选择。
