Diverse Prophage Elements of Serovars Show Potential Roles in Bacterial Pathogenicity.

Nontyphoidal salmonellosis is an important foodborne and zoonotic infection that causes significant global public health concern. Diverse serovars are multidrug-resistant and encode several virulence indicators; however, little is known on the role prophages play in driving these traits. Here, we extracted prophages from seventy-five genomes which represent the fifteen important serovars in the United Kingdom. We analyzed the intact prophages for the presence of virulence genes and established their genomic relationships. We identified 615 prophages from the strains, from which 195 prophages are intact, 332 are incomplete, while 88 are questionable. The average prophage carriage was found to be 'extreme' in Heidelberg, Inverness, and Newport (10.2-11.6 prophages/strain), 'high' in Infantis, Stanley, Typhimurium, and Virchow (8.2-9.0 prophages/strain), 'moderate' in Agona, Braenderup, Bovismorbificans, . Choleraesuis, Dublin, and Java (6.0-7.8 prophages/strain), and 'low' in Javiana and Enteritidis (5.8 prophages/strain). Cumulatively, 61 virulence genes (1500 gene copies) were detected from representative intact prophages and linked to delivery/secretion system (42.62%), adherence (32.7%), magnesium uptake (3.88%), regulation (5%), stress/survival (1.6%), toxins (10%), and antivirulence (1.6%). Diverse clusters were formed among the intact prophages and with bacteriophages of other enterobacteria, suggesting different lineages and associations. Our work provides a strong body of data to support the contributions diverse prophages make to the pathogenicity of , including thirteen previously unexplored serovars.