肉兔大肠杆菌噬菌体的分离及生物学特性分析

Isolation and Biological Characteristics Analysis of Escherichia coli Phage from Meat Rabbit

为了筛选出能高效裂解兔源致病性大肠杆菌的宽谱噬菌体,利用滴定法和双层平板法从规模化肉兔养殖场污水中分离纯化出1株噬菌体vB-EcoS-tE6,利用透射电镜观察菌体形态特征,并研究其生物学特性。结果表明,在透射电镜下该菌头部大致呈六角形,长径59.6 nm,横径57.3 nm,尾部长106.0 nm,无明显的颈部。最佳感染复数0.01,潜伏期20 min,爆发期100 min,裂解量186 pfu/cell。在温度30℃~50℃范围内作用0.5~1.0 h,其活性几乎不受影响,在pH值为6~9范围内可保持很高的效价。能裂解11株兔源大肠杆菌、1株鸡源大肠杆菌和1株产肠毒素性大肠杆菌,属于高效裂解性宽谱噬菌体。说明vB-EcoS-tE6具有代替抗生素应用于肉兔大肠杆菌病防控的开发潜力。

In order to screen a wide spectrum phage that can efficiently split pathogenic Escherichia coli from rabbits,a phage was isolated and purified from sewage of large-scale meat rabbit farm by titration and double plate method,named vB-EcoS-tE6.The morphological characteristics of the phage were observed by transmission electron microscopy,and the biological characteristics were studied.The results showed that under transmission electron microscopy,the head of the phage was roughly hexagon,with a length diameter of 59.6 nm,a transverse diameter of 57.3 nm,a tail length of 106.0 nm,and there was no obvious neck.Its optimal infection complex was 0.01,the incubation period was 20 minutes,the outbreak period was 100 minutes,and the lysis amount was 186 pfu/cell.Under the temperature range of 30℃to 50℃for 0.5 to 1 hour,its activity was almost unaffected,and it could maintain high potency within the pH range of 6 to 9.It could lyse 11 strains of rabbit Escherichia coli,1 strain of chicken Escherichia coli and 1 strain of enterotoxin producing Escherichia coli,and was a high efficient and broad spectrum phage.This showed that vB-EcoS-tE6 had the potential to replace antibiotics in the prevention and control of colibacillosis in meat rabbits.