Variable assortment of prophages provides a transferable repertoire of pathogenic determinants in Salmonella

Abstract

Gene transfer between separate lineages of a bacterial pathogen can promote recombinational divergence and the emergence of new pathogenic variants. Temperate bacteriophages, by virtue of their ability to carry foreign DNA, are potential key players in this process. Our previous work has shown that representative strains of Salmonella typhimurium (LT2, ATCC14028 and SL1344) are lysogenic for two temperate bacteriophages: Gifsy‐1 and Gifsy‐2. Several lines of evidence suggested that both elements carry genes that contribute to Salmonella virulence. One such gene, on the Gifsy‐2 prophage, codes for the [Cu, Zn] superoxide dismutase SodCI. Other putative pathogenicity determinants were uncovered more recently. These include genes for known or presumptive type III‐translocated proteins and a locus, duplicated on both prophages, showing sequence similarity to a gene involved in Salmonella enteropathogenesis (pipA). In addition to Gifsy‐1 and Gifsy‐2, each of the above strains was found to harbour a specific set of prophages also carrying putative pathogenicity determinants. A phage released from strain LT2 and identified as phage Fels‐1 carries the nanH gene and a novel sodC gene, which was named sodCIII. Strain ATCC14028 releases a lambdoid phage, named Gifsy‐3, which contains the phoP/phoQ‐activated pagJ gene and the gene for the secreted leucine‐rich repeat protein SspH1. Finally, a phage specifically released from strain SL1344 was identified as SopEΦ. Most phage‐associated loci transferred efficiently between Salmonella strains of the same or different serovars. Overall, these results suggest that lysogenic conversion is a major mechanism driving the evolution of Salmonella bacteria.

Partial Analysis of the Genomes of Two Nontypeable Haemophilus influenzae Otitis Media Isolates

“…Of more interest, was the identification of strain 1885MEE-specific homologues of genes from the Gifsy 1 and 2 and Fels-2 prophages. Gifsy 1 and 2 were originally identified in S. enterica serovar Typhimurium and have been implicated in Salmonella virulence (19). Fels-2 has been identified in S. enterica (7).…”

Ecological and Evolutionary Benefits of Temperate Phage: What Does or Doesn't Kill You Makes You Stronger

“…[28] Carriage of multiple prophages -polylysogeny -is common among pathogens, allowing acquisition of multiple traits and contributing to diversity in disease pathology. [29][30][31] Prophage acquisition plays an important role in the contemporary evolution of a range of pathogens. More than half of the genome variation in group A Streptococcus (GAS) strains, each of which is responsible for a characteristic array of syndromes from toxic shock syndrome and necrotizing fasciitis, Figure 1.…”

The evolution and distribution of phage ST160 withinSalmonella entericaserotype Typhimurium

“…The emergence of other phage types such as RDNC-April06 containing ST160 reflects the spread and uptake of the phage within the New Zealand S. Typhimurium population. The emergence and decline of epidemic strains of Salmonella has been described [32] and is due to a number of factors including acquisition of virulence factors [33] but susceptibility to new phages may well be critical to changes in S. Typhimurium populations.…”