Broad-Host-Range Phage GSP006 Effectively Controls Horizontal Transmission of Salmonella Pullorum in Poultry Feed and Drinking Water

Background Salmonella enterica subsp enterica serovar Pullorum ( Salmonella Pullorum) is the major pathogen that is harmful to the poultry industry in developing countries. This bacterium is susceptible to acute systemic disease and severe gastrointestinal disease in chicks and is highly lethal. As a natural alternative to conventional antimicrobial agents, phage therapy is increasingly recognized as highly effective and promising for the control of multidrug-resistant bacterial infections, including salmonellosis caused by Salmonella . Results In the current study, a broad-host-range phage, GSP006, targeting Salmonella Pullorum was isolated from poultry farm wastewater. It exhibits lytic activity against Salmonella Pullorum, Salmonella Enteritidis and Salmonella Typhimurium and other serotypes of Salmonella in host range tests. Genomic analysis revealed that GSP006 possesses a double-stranded DNA (dsDNA) genome of 42,165 bp with a G + C content of 50%. Phylogenetic analysis based on the large subunit of terminase confirmed that GSP006 belongs to the genus Jerseyvirus. Biological characterization showed that phage GSP006 was stable to heat (70°C for 1 h) and pH ( pH 3 and pH 11 for 1 h). In addition, the phage had a short latent period of about 20 min, followed by the lysis phase. In vitro experiments, phage GSP006 was able to inhibit the bacterium for more than 6 h at 37°C under different infection multiplicities. In the bacteriostatic test of poultry feed and drinking water, phage GSP006 (Multiplicity of Infection, MOI = 100, 1000, 10000) was able to inhibit the growth of Salmonella Pullorum at 37°C. These results suggest that phage GSP006 is expected to be an antidote to the horizontal transmission of Salmonella Pullorum. Conclusions The broad-host-range phage GSP006 exhibits excellent environmental stability and demonstrates strong inhibitory effects on the growth of Salmonella Pullorum in poultry feed and drinking water. It holds promise as an effective means of inhibiting the horizontal transmission of Salmonella Pullorum.