肠侵袭性大肠埃希菌噬菌体DK-13的生物学特性及应用OA北大核心CSTPCD

[Objective]Selection and isolation of phage that can lyse Enteroinvasive Escherichia coli(EIEC),analyzing its biological characterization,and investigating its sterilizing effect on contaminated pork.[Method]The double-layer agar method was used to isolate phages,and then the optimal multiplicity of infection,one-step growth curve and other biological characteristics of the isolate were determined.The genetic genomes were sequenced and analyzed,and the lysis efficiency was evaluated.[Result]A bacteriophage that specifically lysed EIEC was isolated from hospital sewage and named DK-13.It has a typical tadpole-like morphology,consisting of a head and a contractile helical symmetric tail.It belongs to the family Myoviridae.The biological characterization showed that the optimal multiplicity of infection was 0.01,the incubation period was about 10 min,the lysis period was about 70 min,and the phage DK-13 was able to survive at 50℃and pH 5.0-10.0.The whole genome sequencing showed that the phage genome was about 172 275 bp in length,with a GC content of 40.18%,and was predicted to have a total of 293 open reading frames(ORFs),and no resistance genes or virulence genes were found.the sterilization effect in the contaminated pork was good,and the number of host bacteria significantly reduced.[Conclusion]A new virile phage DK-13 was isolated and identified,which has the advantages of short incubation period and high cleavage efficiency,and has great potential for application in food safety.