关键词: 产单核细胞李氏杆菌, 噬菌体, 分离, 鉴定

Abstract: The purpose of this study is to obtain natural Listeria monocytogenes phage, provide new biological agents for the prevention and treatment of listeriosis, reduce the use of antimicrobial agents, and inhibit the production of antimicrobial resistance of pathogens. Using L. monocytogenes as the host, the slaughterhouse sewage was screened by double-layer agar plate method, and the phage was obtained. Application value of the phage were evaluated by transmission electron microscope, growth characteristics detection (temperature, pH, one-step growth curve, multiplicity of infection, the effect of organic solvents), genome restriction endonuclease digestion and whole genome sequencing. In this study, several strains of L. monocytogenes phage were isolated, and one of the phages with the stronger lytic ability and genetic stability was selected, and named LP8; as myotail phage under electron microscope, can lyse 18 strains of L. monocytogenes and 5 strains of Listeria welshimeri, it was determined that the multiplicity of infection of LP8 was 1, the optimum growth temperature was 45℃, and the pH was 7. During 6 kinds of organic solvents, only isoamyl alcohol could inactivate LP8 completely. The extracted genome was identified by restriction endonuclease digestion and identified as double-stranded DNA, the genome size was 87 038 bp, contained 120 coding genes, the cumulative length of coding genes was 76 326 bp, the average length of coding genes was 636 bp, and the proportion of coding region was 87.69%. In this study, the phage of L. monocytogenes was isolated, and its phage ability and application value were identified. Compared with other phages, the isolated LP8 stronger ability to adapt environmental changes and lyse bacterial. It provides a basis for the subsequent establishment of L. monocytogenes phage library and other applications of L. monocytogenes phage.

Key words: Listeria monocytogenes, phage, isolation, identification