Isolation, characterization, and genome analysis of vB_SenS_TUMS_E19, a polyvalent bacteriophage against Salmonella enteritidis

Abstract

Aims: Salmonellosis is a critical, common infectious disease afflicting people and animals alike, that is caused by Salmonellabacteria. With bacteria showing resistance to antibiotics, new methods should be introduced to prevent and treat this disease. To that end, bacteriophages are promising choices. Methods and Results: In this study, phage vB_SenS_TUMS_E19 (E19) was isolated from poultry wastewater against Salmonella enteritidis. Phage characteristics, including plaque formation, transmission electron microscopy, structural protein profile, host range, growth curve, pH and temperature stability were determined. The extracted genome was sequenced, and annotated using standard bioinformatics tools. Average Nucleotide Identity (ANI) and phylogeny were used to compare the phage genome with other Salmonella phages. Following morphological analysis, phage E19 turned out to belong to the Siphoviridae family. It worked on various strains of Salmonella but had no effect on bacteria of other genera. The burst size was approximately 156 plaque-forming units per cell (PFU per cell) and phage was stable at different temperatures as well as pH values. The genome of E19 is a linear dsDNA molecule of 42,813 bp whose G+C content stands at 49.8%. Out of 62 detected putative protein-coding genes, only 44 gene products with known functions were found in database searches. Neither tRNA genes nor genes associated with antibiotic resistance, virulence factor, and lysogeny formation were detected in the genome. Conclusion: The E19 showed lytic activity against some Salmonella enterica serovars and Salmonella pullorum. Genome-based studies exhibited the absence of antibiotic resistance and virulence genes, indicating the safety of this phage for environmental and clinical applications. Significance and Impact of the Study: The findings indicate that the lytic polyvalent E19 is an antibacterial agent that could control Salmonella in food samples and helps with Salmonellosis prevention and treatment.