Isolation,identification and antibacterial effect of a Salmonella phage

ZHOU Jun; HUANG Junqing; DU Tingting; QIN Jinmeng; ZHANG Siwei; SUN Shibiao; SUN Xincheng

doi:10.12187/2026.01.006

Abstract：[Objective]This study aims to explore the antibacterial effect of phages on Salmonella in food.[Methods]Phages were isolated and purified from wastewater samples collected from a wastewater treatment plant in Zhengzhou,with Salmonella typhimurium as the host bacterium,by the double-layer agar plate method.Their biological characteristics,genomic features,and antibacterial effects on S.typhimurium in artificially contaminated milk and egg white were investigated.[Results]The optimal multiplicity of infection(MOI)of the isolated and purified phage ST-1 was 0.1,with a maximum titer of 10.45 lg PFU/mL.Its latent period was 20 min,the lysis period was 70 min,and the burst size was approximately 106.5 PFU/cell.It had a narrow host range,being able to lyse only S.typhimurium and Streptococcus pneumoniae.It exhibited good stability,maintaining activity within a temperature range of 30～60℃and a pH range of 5～10,while also being insensitive to chloroform.Phage ST-1 belongs to the order Caudovirales.Its genome size is 84 672 bp,with a GC content of 38.82%,and it contains 142 open reading frames(ORFs).It does not carry resistance genes or virulence genes and can significantly inhibit the growth of S.typhimurium in artificially contaminated milk and egg white.[Conclusion]Phage ST-1 has high lysis efficiency,good thermal stability,acid-base tolerance,safety,and control effects,which can provide a reference for the development of targeted biocontrol agents against Salmonella.