畜牧兽医学报2017，Vol.48Issue(4)：706-713,8.DOI:10.11843/j.issn.0366-6964.2017.04.014
一株裂解性奶牛乳房炎源屎肠球菌噬菌体的分离及其生物学特性分析
Isolation and Characterization of a Lytic Phage Infecting Enterococcus faecium of Bovine Mastitis
摘要
Abstract
The aim of the present study was to isolate and characterize the phage that could lyse Enterococcus faecium from fecal samples of dairy cattle in Shihezi,Xinjiang,and provide the basic data for the phage therapy as well as prevention.The phage was isolated and purified from dairy cattle fecal samples by double-layer agar plate method.And its plaque characteristics was observed.The purified phage was concentrated,negatively stained with phosphotungstic acid and observed by transmission electron microscopy.The genome of the isolated phage was sequenced.Its genetic and evolutional history were analyzed.The host range,optimal multiplicity of infection (MOI),one-step growth curve,temperature,and pH stability of the phage were investigated by double-layer agar plate methods.A lytic phage of Enterococcus faecium was isolated and purified,and named vB_EfaM_XJ3.The phage plaques were circular,clear and transparent with smooth edge,and its diameter was 1.2-1.5 mm.The electron microscope observation showed that the phage particles,whose head was twenty-sided,head length was about 53.15 nm,tail length was about 14.42 nm× 199.62 nm.The genome of the phage was comprised of double strand DNA,the size was 157.189 kb with GC content of 50.27％.The homology of amino acid sequence of phage vB_EfaM_XJ3 with Salmonella phage SKML-39 was 98％.The study of biological characteristics showed that the vB_EfaM_XJ3 only crack its host bacteria at present.The optimal MOI was 0.001,the incubation period was 15 min,the burst period was 175 min and the burst size was 84.The phage could withstand the temperature up to 50 ℃ and keep stable titer under pH 5.0-11.0.A lytic phage of Enterococcus faecium was isolated and identified.Its biological characteristics and genetic were analyzed.The results laid the foundation for the further research and application of the antibacterial agent for Salmonella and Enterococcus faecium.关键词
奶牛乳房炎/屎肠球菌/裂解性噬菌体/生物学特性/进化树分析Key words
bovine mastitis/Enterococcus faecium/lytic phage/biological characteristics/phylogenetic analysis分类
农业科技引用本文复制引用
张倩,于会举,孙耀强,张湘莉兰,张培生,刘鸽,屈勇刚,童贻刚,李岩..一株裂解性奶牛乳房炎源屎肠球菌噬菌体的分离及其生物学特性分析[J].畜牧兽医学报,2017,48(4):706-713,8.基金项目
国家自然科学基金(31560699) （31560699）
新疆生产建设兵团应用基础研究计划项目(2015AG012) （2015AG012）
