用质粒DNA指纹图谱法分析猪水肿病大肠杆菌的流行病学特征

从广西各地病死猪器官、组织中分离到17株细菌,经细菌形态、培养特性及生化反应鉴定为大肠杆菌。作本动物回归试验、小白鼠致病性试验和溶血试验结果表明,全部为致病性大肠杆菌。血清定型鉴定结果发现,菌株血清型分布不规律。17株致病性大肠杆菌的质粒指纹图谱显示:来源于不同猪群的菌株GP20-3和GP25-1以及GP18-9和GP8-3分别具有相同的质粒图谱,说明发病猪群传染源的首发菌相同。所有菌株都含有1条大小相同的质粒带,广西流行的猪水肿病主要是由在遗传学上具有高度同源相关性的大肠杆菌的广泛流行传播所引起。菌株GP18-9和GP8-3的质粒指纹图谱相同,但它们的血清型却不一致的现象,可作为自然条件下,同一质粒在不同血清型大肠杆菌中扩散转化的一个生物学依据。

Epidemiologicai Analysis on Escherichia Coli of Edema Disease of Swine Using Plasmid DNA Finger Printing

Seventeen strains of escherichia coli(E.coli)from organs and tissues of the infected swines in some forms in Guangxi had been isolated and identified by the methods of bacterial morphological observation,cultivation characteristic and bio-chemical reaction.The examination for blood-plate hemolysis and pathogenicity in susceptible swines and chmice indicated that all strains were virulent E.coli.The distribution of sero-types of isolates was scrambling.In the screening test of plasmid DNA from 17 strains of E.coli isolates,the results showed that all strains had one common plasmid profile and the swines were infected by high homology E.coli in genetics,and that isolates(GP_(20-3),GP_(25-1)) and(GP_(18-9),GP_(8-3)) from different infected flocks respectively had same plasmid and the original pathogeny in infected flocks was common.Isolates GP_(18-9) and GP_(8-3) had similar plasmid profiles,but their sero-types were dissimilar.This confirmed that plasmids could be transfered among different sero-type E.coli.