Division of Preventive Veterinary Medicine and Public Health, Department of Veterinary, Federal University of Viçosa. PH Rolfs Avenue, s/n, Zip Code: 36570-000, Viçosa, MG, Brazil.
Can J Microbiol. 2013 May;59(5):291-3. doi: 10.1139/cjm-2013-0053. Epub 2013 Apr 1.
Escherichia coli is capable of producing several virulence factors involved in the pathophysiology of bovine mastitis. Cell surface structures such as flagella, pili, and other outer membrane adhesins are considered essential for biofilm formation on abiotic surfaces. The aim of this study was characterize the molecular profile of E. coli isolates obtained from mastitic milk by using the technique of pulsed-field gel electrophoresis (PFGE) and evaluating results within the pulsetypes formed with the presence of virulence genes involved in biofilm production. Twenty-seven E. coli biofilm-producing isolates were obtained from mastitic milk samples belonging to Brazilian Agricultural Research Corporation; these samples were analyzed by PFGE. We identified 9 (I to IX) different phylogenetic groups with a similarity of 90% and observed the presence of fimA (large subunit of the fimbriae type 1) and csgA gene (large subunit of curli fimbriae) in all isolates. Sixteen isolates had the gene fliC (flagellin). Evaluation of the genetic profile carried out through the PFGE showed that the bacteria do not share the same origin. It was not possible to associate the biofilm production capacity with the presence or absence of related genes. Therefore, strains of environmental mastitis-causing E. coli present different pathotypes.
大肠杆菌能够产生几种与牛乳腺炎病理生理学相关的毒力因子。细胞表面结构，如鞭毛、菌毛和其他外膜黏附素，被认为是在非生物表面形成生物膜的必要条件。本研究的目的是通过脉冲场凝胶电泳（PFGE）技术对从乳腺炎牛奶中分离到的大肠杆菌进行分子特征分析，并评估与生物膜形成相关的毒力基因存在时形成的脉冲类型的结果。从巴西农业研究公司的乳腺炎牛奶样本中获得了 27 株大肠杆菌生物膜产生株，通过 PFGE 进行了分析。我们确定了 9 个（I 至 IX）不同的系统发育群，相似度为 90%，并观察到所有分离株均存在 fimA（1 型菌毛的大亚基）和 csgA 基因（卷曲菌毛的大亚基）。16 个分离株具有 fliC 基因（鞭毛蛋白）。通过 PFGE 进行的遗传谱评估表明，这些细菌并非来自同一来源。无法将生物膜产生能力与相关基因的存在或不存在联系起来。因此，引起环境性乳腺炎的大肠杆菌菌株具有不同的病理型。
