Diet and commensal E. coli control Salmonella Typhimurium infection susceptibility in mice
Fatty diets affect health and change the gut microbiota. Whether these diet-induced changes promote Salmonella Typhimurium diarrhea has remained unclear. This was explored in a recent Nature Microbiology publication by Sandra Wotzka and Markus Kreuzer from the Hardt lab.
The effect of fat on the risk of infection with the major food poisoning bacterium Salmonella Typhimurium has now been tested in mice. While control mice eating a low-fat mouse diet fended off the pathogen, shifting the animals to a high-fat diet promoted the Salmonella Typhimurium infection. This effect was traced to bile salts, natural detergents released into the gut for fat digestion. These bile salts inhibit the microbiota and thereby promote the growth of the bile-resistant pathogen. The pathogen blooms not only accelerate the infection, but also help to spread antibiotic resistance plasmids, a major public health concern.
So, why is fat not known as a risk factor for Salmonella diarrhea? In fact this research identifies not only the problem, but also a potential solution: The prevalence of bile-resistant E. coli strains in healthy microbiotas. When introduced into mice, E. coli blocked the infection. Future studies should test how E. coli achieves this protection.
Link to the publication in external page Nature Microbiology.