Abstract: The detection rates of Pan drug resistant bacteria and multi drug resistant bacteria are increasing, and phages have good application prospects in preventing the transmission and infection of treatment resistant bacteria. The purpose of this study was to isolate mild bacteriophages with wide cleavage spectrum and enrich the Salmonella mild phage library. A temperate phage named Salmonella virus PEA2-3 was isolated and purified using mitomycin C induction, and some of its biological characteristics were determined and bioinformatics analysis was performed. TEM revealed that the phage head was approximately 61 nm wide and the tail was 93 nm long, and it belonged to the order Caudovirales, genus Rosemountvirus. The optimal multiplicity of infection was 0.01; The one-step growth curve showed an incubation period of 20 min and a lysis period of approximately 80 min; And was able to lyse Salmonella (38/72) and Escherichia coli (23/52) of different origins, which indicated it to be a lysogenic phage with a wide lysis spectrum, that had better application value. The genome sequencing results showed that its genome was 52 770 bp in length with a GC content of 45.99%, and the genome was annotated to a total of 73 CDS, 8 CDS of which were assigned to known functional proteins, and no antibiotic resistance genes or virulence genes was existed. The whole genome of phage PEA2-3 was submitted to the GenBank database of NCBI and obtained the sequence number of MW508890. The results suggest that this strain is a highly efficient and mild phage with a wide lytic spectrum that can lyse Escherichia coli and Salmonella simultaneously, providing a good application basis for the prevention and control of the spread of drug-resistant bacteria.

Key words: temperate phage, Salmonella, biological properties, genomic analysis