Abstract:A virulent phage, named as ΦSHDA-1, was isolated from sewage by a double-layer plate method using Salmonella typhimurium (CMCC50115) as the host strain. The preliminary study of its biological characteristics and genome was conducted. The results showed that ΦSHDA-1 plaque was bright and the edge was clear. The transmission electron microscopy showed that ΦSHDA-1 had a head diameter of (53±8) nm and a tail length of (112±12) nm which belong to the Siphoviridae family. The best multiplicity of infection was 0.00001. The one-step growth curve showed the latent period was 25 min and the burst period was 30 min with an average lysis amount of 36.52 PFU/cell. ΦSHDA-1 was stable at 30~50 ℃ and pH 2~10, exhibiting a good lysis effect on Salmonella typhimurium. A total of 6 coutig with length of 40 523 bp and 51% of GC were obtained by whole-genome sequence. A total of 59 coding sequences were obtained by Prokka annotation, which contained an lysin gene without tRNA and rRNA. Through the open reading frame and the analysis of CARD and VFDB, no drug resistance genes and virulence genes were detected.
