13株仔猪黄痢病原菌的分离鉴定及致病基因的PCR检测

Isolation and Identification of Thirteen Pathogenic Strains Associated with Piglets Diarrhea and Detection of Virulence Gene among the Isolates by PCR

[目的]对从仔猪黄痢病死仔猪肝脏中分离的13株病原菌进行分离鉴定及其致病基因的PCR扩增,为该病的微生物学诊断及其病原的致病机理探讨提供参考资料。[方法]分别采集死于仔猪黄痢病仔猪肝组织,在麦康凯琼脂上进行病原菌的分离培养、革兰染色镜检、生化试验、DNA模板的制备、致病基因PCR扩增。[结果]从几个猪场采集的仔猪黄痢病死仔猪肝脏中分离到13株病原菌,其中一株为革兰阳性球菌,其余均为革兰阴性短杆菌,经PCR检测结果表明均为产肠毒素大肠杆菌并且均含有HPI^+。[结论]从上述结果可知,从发生仔猪黄痢猪场采集的病死仔猪肝脏中分离的13株病原菌一些为产肠毒素大肠杆菌并且均含有HPI^+,少数肠球菌也可引起仔猪黄痢。

[Objective ]To isolate and identify the pathogenic bacteria from liver samples of dead piglets with diarrhea and detect the virulence gene among the isolates by PCR, and to provide references for the microbiological diagnosis and understanding the pathogenesis of the isolates. [ Methods ]The liver samples of dead piglets with diarrhea were collected to isolate pathogenic bacteria using MacConkey medium; the isolates were identified by gram stain method and biochemical test; the DNA templates of the isolates were prepared and used to detect the presence of virulence gene by PCR. [ Results ] A total of thirteen strains were isolated from the clinical samples, one of them was identified as gram positive cocci and the other ones were identified as gram-negative short bacillus; the result of the PCR assay indicated that the bacillus were all enterotoxigenic Escherichia coli （E. coli） and all harbored high pathogenicity island （HPI＋）. [Conclusion]The combined data suggest that the enterotoxigenic E. coli harboring HPP was the etiological agent of piglets diarrhea in the pig farms, and Enterococcus strains may be associated with the occurrence of piglets diarrhea.