Inflammation boosts bacteriophage transfer between Salmonella spp

Area of Science:

• Microbiology
• Genetics
• Evolutionary Biology

Background:

• Bacteriophage transfer, or lysogenic conversion, is a key driver of bacterial virulence evolution.
• The factors governing lysogenic conversion dynamics within host environments remain poorly understood.

Purpose of the Study:

• To investigate the dynamics of SopEΦ prophage transfer between Salmonella Typhimurium strains in a murine model.
• To elucidate the role of host inflammation in mediating bacteriophage transfer and its impact on bacterial evolution.

Main Methods:

• Utilized a murine Salmonella Typhimurium diarrhea model to study prophage transfer.
• Quantified lysogenic conversion rates under conditions with and without induced gut inflammation.
• Analyzed the molecular mechanisms linking inflammation, SOS response, and phage antirepressor expression.

Main Results:

• Gut inflammation and enteric disease significantly increased SopEΦ transfer (>55%) in Salmonella Typhimurium within 3 days.
• Absence of inflammation reduced SopEΦ transfer by up to 10^5-fold.
• Inflammation-induced SOS response and Tum antirepressor expression were identified as critical for promoting phage transfer.

Conclusions:

• Host-induced inflammation is a critical factor promoting bacteriophage transfer and bacterial virulence evolution.
• Mucosal vaccination prevented inflammation, thereby abolishing prophage transfer, suggesting a generalizable strategy.
• Targeting disease-driven phage transfer could be a novel approach to control pathogen evolution.