致仔猪水肿病大肠杆菌的分离、鉴定及生物学特性

Detection,Identification and Biological Characterization of Escherichia coli Eliciting Edema of Piglet

从不同省份发生水肿病的仔猪的脏器中分离到 7株细菌 ,通过菌体形态、菌落形态、革兰氏染色特性、生化特性、血清型等一系列的鉴定 ,确认为大肠埃希氏菌。动物致病性试验表明 ,该菌对小鼠有较强的致病性 ,可引起小鼠死亡。肉汤培养物无菌滤液能致死小鼠且剖检见相关脏器水肿 ,引起 Vero细胞死亡。对主要毒力基因 SL T- Ile及 F18进行扩增 ,SL T- Ile全部阳性 ,5株 F18为阳性 ,对 L T1及 ST1扩增则全为阴性。药敏试验证明 ,各菌株的耐药谱不同。各菌株攻毒于断奶仔猪 。

Seven strains Escherichia coli isolated from provinces having edema were identified by gram dyeing,biochemical reaction and serotying.These strains had pathogenicity and were able to produce Vero toxin,which could be confirmed by following examinations.Their broth culture could lead Kunming mice to death.Axenic filtrate of the broth culture could induce Kunming mice and Vero cell death.These strains were tested by PCR to detect genes of SLT-Ile,F18,LT1 and ST1.Seven strains were positive for SLT-Ile,five strains were positive for F18,but all were negative for LT1 and ST1.Which accorded with the literature previously reported.Antibiotics susceptibility test showed their resistance patterns were different.All of the seven strains could reproduce the edema disease of weaning piglets.