中文摘要：

试验从鸡场周围环境中采集土样，在伊红美蓝培养基平板上分离纯化大肠杆菌，然后以其为宿主，分离相应的噬菌体，并研究其生物学特性。结果表明，共分离到大肠杆菌4株，经16S rDNA鉴定为埃希氏大肠杆菌。其中，以大肠杆菌LY4为宿主分离纯化到1株烈性噬菌体，负染经电镜观察该噬菌体由多面体头部及尾部组成，噬菌斑直径为2.5～3.8 mm，效价2.0×1010 PFU/mL，最佳感染复数为0.0001；在温度－20～37 ℃、pH 5.0～10.0范围内该噬菌体表现出良好的稳定性，但在人工胃液（pH 1.2）条件下，即可导致死亡；测定其一步生长曲线，该噬菌体潜伏期为20 min，裂解能力强，以上特性表明该噬菌体在鸡舍环境治理中具有潜在的应用价值。

英文摘要：

4 of E.coli strains were isolated from the soil of chicken farm on the EMB medium, and further identified as Escherichia coli by 16S rDNA sequence analysis. One virulent phage ΦLY4 was isolated when propagated on the E.coli LY4 as host cells. The phage had the hexagonal head and tail after observing with negatively stained method by electron microscope. The drastic diameter of this phage was 2.5 to 3.8 mm in size, and its phage titer was about 2.0×1010 PFU/mL, the optimal multiplicity of infection was 0.0001. It kept high stability at the temperature of －20 to 37 ℃ and pH at 5.0 to 10.0. Its viability was lost completely at the simulated gastric conditions （pH 1.2）. The growth curve showed that its incubation and burst phase was 20 min, and the lysis ability was strong. All of these properties showed that the phage ΦLY4 had a potential application in the control of environmental pollution.