A study led by researchers at UC Davis has found how the bacteria Salmonella enterica—a common cause of food poisoning—exploits immune response in the human gut to enhance its own reproductive and transmission success. The strategy gives Salmonella a growth advantage over the beneficial bacteria that normally are present in the intestinal tract and promotes the severe diarrhea that spreads the bacteria to other people.
The study, “Gut inflammation provides a respiratory electron acceptor for Salmonella,” is published in the Sept. 23 issue of the journal Nature.
“The human body normally has 10 times more microbes than human cells that help protect us against infection from disease-causing bacteria,” said Andreas Bäumler, professor of medical microbiology and immunology at the UC Davis School of Medicine and the principal investigator of the study. “We have discovered Salmonella’s cunning trick that allows it to quickly take over and outgrow the beneficial microbes in our intestine.”
All bacteria must generate energy in order to live and reproduce, either by respiration—which usually requires oxygen—or fermentation. Because essentially no oxygen is available in our intestines, the beneficial bacteria that reside there tend to use fermentation, which is less efficient than respiration for obtaining energy.