The nutrient is composed of fructose-asparagine, a sugar and amino acid stuck together. Researchers at the university discovered Salmonella bacteria is 1,000 times less effective at sustaining disease when they can't access this single nutrient. Blocking activation of one of five geneses that transport fructose-asparagine to Salmonella cells could be a new way to fight the infection.
“For some reason, Salmonella really wants this nutrient, and if it can’t get this one, it’s in really bad shape,” said Brian Ahmer, associate professor of microbial infection and immunity at The Ohio State Univ. and lead author of the study. “If you could block Salmonella from getting that nutrient, you’d really stop Salmonella.”
Ahmer and colleagues found the fructose-asparagine by first identifying the genes that Salmonella needs to stay alive during the active phase of gastroenteritis, when the inflamed gut produces symptoms of infection.
The researchers found five genes that had to be expressed to keep Salmonella bacteria from losing fitness during gastroenteritis. They then determined that those five genes work together to transport a nutrient into the Salmonella cell. Researchers believe that the genes needed to acquire the nutrient could be a promising drug target. Ahmer said nutrient transporters have not been considered drug targets before because researchers assumed there will hundreds more transporters.
“That was one of the big surprises: that there is only one nutrient source that is so important to Salmonella. For most bacteria, if we get rid of one nutrient acquisition system, they continue to grow on other nutrients,” Ahmer said. “In the gut, Salmonella can obtain hundreds of different nutrients. But without fructose-asparagine, it’s really unfit.”