猪源大肠杆菌分离、血清型鉴定及脉冲场凝胶电泳分型

Isolation,serotyping and genotyping of Escherichia coli from pigs

采集8个猪场的120份健康猪肛门拭子,进行大肠杆菌分离和O抗原血清型鉴定,再将分离的菌株与已知的具有相同血清型的大肠杆菌致病株进行基因分型,而后将二者的脉冲场凝胶电泳(PFGE)图谱进行比较分析,以找出其中的相关性。试验共分离到大肠杆菌97株,其中80株分属于39种O抗原血清型,上海和沈阳地区O149为优势血清型,无锡地区O93为优势血清型。80个分离株中,77株能够进行PFGE分型,3株不能分型。40株已知的大肠杆菌菌株中,1株不能够分型。各规模化养猪场均可分离到致病血清型菌株,大肠杆菌血清型分布呈地区性和多样性。PFGE相似率在85%以上的致病性大肠杆菌血清型均相同,但血清型相同的大肠杆菌PFGE不一定相同。未发现与已知菌株PFGE相似率在85%以上的分离菌株,说明本试验分离的大肠杆菌菌株与致病性菌株之间没有流行病学相关性。

One hundred and twenty swine swab samples were taken from 8 farms. Escherichia coli was isolated and serotyped. Pulsed-field gel electrophoresis （PFGE） typing was carried out in the isolated strains and stocked strains of E. coli. The PFGE profiles were compared in the E. coli strains from the same serotype. 97 strains were isolated and 80 belonged to 39 different O antigen serotypes. O149 was the main serotype in Shanghai and Shenyang. Serotype 093 was mainly found in Wuxi. 77 strains could be genotyped by PFGE in 80 isolates with de- fined O serotypes, and 39 could be identified by PFGE in 40 stocked strains. Pathogenic E. coli was isolated from all the swine farms, but the distribution of the serotypes varied in different areas. The strains with more than 85% similarity in PFGE profiles had same pathogenic se- rotypes. However, the strains with the same serotypes had a wide range of PFGE profiles. No isolates were found with more than 85% simi- larity in PFGE profiles to the stocked strains, indicating that there is no epidemiological correlation between the isolated and stocked strains.