致仔猪水肿病大肠杆菌的分离鉴定及对小鼠的毒力研究

Isotation,Identification and Virulence of Escherichia coli Causing Piglet Edema Disease in Mus musculus

从发病仔猪脏器中分离到一株细菌,进行了初步鉴定。结果表明,该菌为致猪水肿病大肠杆菌,在血平板上呈β溶血,经PCR鉴定该菌株具有产毒素基因,对小鼠毒力强,能致其发病死亡,血清型为O141,是临床多发血清型菌株。将细菌培养物和裂解毒素分别经皮下和尾静脉两种途径接种于体重为16~18 g昆明系小鼠,小鼠腹腔注射细菌培养物后12~48 h死亡,不表现神经症状,剖检水肿病病变特征不典型;小鼠于尾静脉注射裂解毒素后4~48 h,出现典型的眼睑水肿和后躯瘫痪等神经症状,直至死亡。该菌株致小鼠死亡的最小毒素剂量为0.2 mL/只。研究结果表明,小鼠可作为诊断仔猪水肿病模型,也进一步证明试验菌株为致猪水肿病菌株,可作为制备疫苗菌株。

In this experiment,the bacteria was isolated from the organs of pigs to carry out preliminary appraisal.The results showed that bacteria of hemolytic E.coli in the blood plate was β hemolysis;this strain could produce toxin gene that tested with PCR,and the toxicity in Mus musculus was strong which caused its sick and die;its serotype was the clinical multiple serotype O141.Bacteria cultures and decomposed toxins were inoculated into Kunming Mus musculus of 16~18 g body weight through the skin and tail vein two ways.Mus musculus by intraperitoneal injection of bacteria cultures,was dead after 12~48 h,didn＇t show neurological symptoms,and anatomy edema disease lesion characteristics was not typical;Mus musculus in the tail vein injection of cracking toxin appeared typical eyelid edema,paralysis and other neurological symptoms after 4~48 h until death.The strain induced the death of the minimum toxic dose was 0.2 mL per each only.The results showed that Mus musculus could serve as a model for diagnosis of piglet edema disease.The test strains could caused edema disease of swine,and could serve as a strain of prepare vaccine.