李斯特菌噬菌体的分离鉴定及其裂解特性

Isolation, Identification and Lytic Characteristics of Listeria Phage

以单核细胞增生性李斯特菌(Lm)为宿主菌,从畜禽养殖区污水中分离(Lm)特异的噬菌体,分析其生物学特性、裂解特性及其在食品中的灭菌效果。用双层平板法从污水样中分离Lm噬菌体,PEG/NaCl法沉淀纯化噬菌体,负染色后电镜观察。分析噬菌体对宿主菌的裂解特性及其对温度和pH值的敏感性,同时对该噬菌体进行宿主谱系分析。将噬菌体运用于即食性食品中,分析其潜在的灭菌效果。结果表明:分离的噬菌体为裂解性噬菌体,属长尾噬菌体科,命名为LipG2-5。体外能够高效裂解宿主菌,对温度及pH值亦有良好的耐受性。基因组酶切分析表明,LipG2-5为双链DNA噬菌体。噬菌体谱系分析表明,该噬菌体为1株宽宿谱噬菌体,在固态及液态即食性食品中能够高效杀灭Lm。

The aim of this study is to find a virulent Listeria phage that can inactivate Listeria monocytogenes （Lm） and achieve biological control of Lm in ready-to-eat foods using the phase. The phage was isolated from sewage by double layer plate assay with agar medium. The PEG/NaC1 purified phage was analyzed by electron microscope after negative staining. Host range and biological characteristics of the phage were detected. In addition, the genomic DNA was analyzed by restriction enzyme digestion. Finally, the inactivation effect of the phage on Lrn in ready-to-eat foods was evaluated. The isolated phage, named as LipG2-5, was a lyric member of the Siphoviridae family, which could effectively lyse its hosts. LipG2-5 had a wide range of hosts and revealed excellent tolerance to temperature and pH. According to genomic analysis by restriction enzyme digestion, LipG2-5 was double strand DNA phage. Lrn in ready-to-eat foods could be inactivated within 24 h after LipG2-5 had been added into the foods.