How Gut Inflammation Drives the Evolution of Harmful Bacteria

Inflammation in the gut helps bacterial viruses spread to other strains of bacteria and promotes their success, a new study in mice finds. The results hint that using a vaccine that reduces gut inflammation may be helpful in treating some infections. Bacteriophages, or viruses that infect bacterial pathogens, may also act as vectors of virulence or of antibiotic resistance genes, ultimately making bacterial disease worse for the host.

To gain more insights into this phenomenon, Médéric Diard et al. infected mice with a strain of Salmonella that was infected with the bacteriophage SopEΦ. Inflammation in response to the Salmonella stressed the pathogens themselves, and the resulting damage promoted bacteriophage replication, followed by rupture of the bacterial cell wall and release of the bacteriophages. At this stage, the bacteriophage infected other Salmonella cells, possibly also spreading novel virulence or resistance genes, the authors say. In live mice, administering a vaccine that decreased gut inflammation caused a decrease in SopEΦ-mediated gene transfer, the authors report. They note that targeting inflammation to treat infections offers an advantage over antibiotic therapy, as the former hinders gene transfer and the evolution of pathogens, while the latter promotes bacterial evolution and, ultimately, antibiotic resistance.