A new study released on June 26 reveals that specialized intestinal cells help control Salmonella infections by restricting the bacteria's access to essential metals such as iron and manganese. The research, conducted at the Robert Larner, M.D. College of Medicine at the University of Vermont, provides new insights into how the human body defends itself against one of the most common forms of bacterial food poisoning in the United States.
Salmonella is responsible for more than a million cases of illness annually in the U.S., causing symptoms including diarrhea, fever, and abdominal pain. While most healthy individuals recover without medical intervention, vulnerable populations such as young children, elderly people, and those with compromised immune systems can experience severe or life-threatening complications.
Principal investigator Leigh Knodler, Ph.D., Professor of Microbiology and Molecular Genetics, led a team that discovered epithelial cells lining the intestine play a crucial role in preventing Salmonella from growing within host tissues. According to their findings published in The Proceedings of the National Academy of Sciences this week, these cells use specialized transporters to pump iron and manganese away from intracellular Salmonella after it breaches the intestinal barrier. "This means that if pathogenic bacteria breach the intestinal barrier, then the host has a back-up means of defense," Knodler said.
The researchers employed fluorescent sensors to trace where metal restriction occurs during infection and observed how human cells utilize these transporters to deprive invading bacteria of necessary nutrients. Their results suggest that manipulating metal transport pathways could bolster natural defenses against not only Salmonella but also other food-borne pathogens.
Future research will focus on examining additional metal transporters present in gut epithelial cells—of which there are dozens—to determine their roles in pathogen control and overall nutritional immunity. Collaborators on this study include scientists from University of Wisconsin at Madison; Vanderbilt University Medical Center; and John Salogiannis, Ph.D., at Larner College of Medicine.
