New Study Uncovers Mechanisms of Food Poisoning and Gut Infections

New Delhi: A team of US researchers has uncovered how Salmonella bacteria, a leading cause of food poisoning, infiltrates and thrives in the gut by manipulating the protective bacteria and nutrient environment.

Salmonella is one of the most common culprits behind foodborne illnesses, often found in raw eggs, undercooked poultry, beef, pork, vegetables, and processed foods. According to the World Health Organization (WHO), unsafe food affects around 600 million people annually, causing 420,000 deaths.

The study, published in the Proceedings of the National Academy of Sciences, highlights how Salmonella disrupts the gut’s natural defenses to survive and multiply. The gut is home to trillions of bacteria that produce short-chain fatty acids (SCFAs), essential for combating harmful pathogens. However, Salmonella manages to alter the nutrient balance, enabling its growth even in this hostile environment.

Led by Andreas Baumler, Professor at the University of California-Davis, the researchers discovered that while Salmonella typically invades the small intestine, it also has the ability to spread to the colon. Once in the small intestine, the pathogen triggers inflammation in the gut lining, which disrupts the normal absorption of amino acids from food. This creates an imbalance, making it easier for Salmonella to thrive in the large intestine (colon).

The inflammation caused by Salmonella in the small intestine provides nutrients that fuel its replication in the colon, Baumler explained. Using mice models, the team observed that Salmonella infection reduced amino acid absorption into the bloodstream. Specifically, the levels of lysine and ornithine—two amino acids—rose in the gut during the infection. These amino acids counteract the growth-inhibiting effects of SCFAs, facilitating the pathogen’s survival.

“Our findings show that Salmonella has a clever way of altering the gut’s nutrient environment to its advantage,” Baumler said. “By reducing the body’s ability to absorb amino acids in the ileum, Salmonella creates a more favorable environment for itself in the colon.”

The study’s insights also shed light on gut environment changes in inflammatory bowel disorders like Crohn’s disease and ulcerative colitis. These findings could pave the way for improved treatments for gut infections and inflammatory conditions.

This breakthrough deepens our understanding of how pathogens exploit gut inflammation and nutrient imbalances to establish infections, underscoring the need for better prevention and treatment strategies.