一株空肠弯曲菌噬菌体的分离及其生物学特性鉴定

The isolation and characterization of a lytic phage infecting Campylobacter jejuni

目的从鸡粪便中分离裂解性空肠弯曲菌噬菌体,研究其生物学特性,为治疗和防控空肠弯曲菌感染奠定基础。方法以空肠弯曲菌NCTC11168为宿主菌,采用双层平板法从鸡粪便中分离空肠弯曲菌噬菌体,并测定其噬菌斑、遗传物质、裂解谱、最佳感染复数、一步生长曲线、酸碱和热稳定性等生物学特性。结果分离得到空肠弯曲菌噬菌体CP7,其噬菌斑直径约为1~2mm,清晰透明,边缘光滑,无晕环。CP7裂解能力较强,能裂解13株空肠弯曲菌分离株。电镜观察噬菌体属于肌尾噬菌体属,具有典型的弯曲菌噬菌体的终端泡和空头,有一直径80nm的正多面体对称头部,一长约100nm、宽15nm的尾部,有肌鞘并可发生收缩。CP7的遗传物质为ds DNA,能被限制性内切酶HindⅢ、HhaⅠ、DraⅠ、Eco RⅤ和TaqⅠ切开,属于Ⅲ组空肠弯曲菌噬菌体,基因组大小约为140kb。结论 CP7为裂解性噬菌体,裂解能力较强,对不同温度、p H也有较强的适应能力,具有开发为空肠弯曲菌抑菌制剂的潜力。

Objective To isolate and samples, analyze its biological properties, and Campylobacterjejuni phages were isolated by identify a lytic Campylobacterjejuni phage from chicken feces provide the basic data for therapy as well as prevention. Methods the double-layer agar culture method from chicken faeces samples, using Campylobacter jejuni NCTC11168 as an indicator. Its biological properties were identified by plaque, transmission electron microscopy （TEM）, genetic material, host range, optimal multiplicity of infection （MOI）, one- step growth experiment, pH, and thermostability. Results A bacteriophage of Campylobacterjejuni was successfully isolated, and named as bacteriophage CP7. The morphology of plaque was round, transparent plaques with clear boundaries. Each plaque was from lmm to 2ram in diameter. 13 strains of Campylobacterjejuni could be lysed by CP7. Results of the electron microscope showed phages with a typical terminal bleb and an empty head. The phages had a regular polyhedron symmetry head with a diameter of 80nm, a tail with length of approximately 100nm and width of about 15nm, and a muscular sheath for shrinking. The phages belong to the family of Myoviridae. The genome of CP7 is ds DNA, which can be cut by restriction enzymes HindⅢ, Hha I , Dra I, EcoRV, and Taq I . The genome size of CP7 is about 140kb, belonging to the group Ⅲ Campylobacterjejuni phage. Conclusion CP7 is lytic bacteriophages specific for Campylobacterjejuni. The phage has a strong lysis ability, and can stably present at different temperatures and pH spectrums, which shows its potency to be developed as a novel alternative for the Campylobacter ieiuni control.