A UC Davis study reveals Salmonella uses electrical fields in the gut to navigate and cause infection, offering new insights into battling bacterial diseases and chronic illnesses such as IBD.
How do harmful bacteria like Salmonella manage to bypass our gut’s defenses to cause infections? A groundbreaking study by UC Davis Health researchers has uncovered an innovative bioelectrical mechanism that these pathogens exploit to find entry points in the gut.
The findings, published in Nature Microbiology, have profound implications for understanding bacterial infections and developing new preventive treatments.
Bacterial Border Crossers
Salmonella, responsible for approximately 1.35 million illnesses and 420 deaths annually in the United States, faces a formidable task in infecting the human body.
“When ingested, Salmonella find their way to the intestines. There, they are vastly outnumbered by over 100 trillion good bacteria (known as commensals). They are facing the odds of one in a million!” Yao-Hui Sun, lead author and research scientist at UC Davis Health, said in a news release.
To understand how Salmonella navigates this dense microbial jungle, the researchers observed the movement of S. Typhimurium (a strain of Salmonella) and compared it to non-pathogenic Escherichia coli (E. coli).
Understanding the Gut Landscape
The gut’s complex structure includes areas like the villus epithelium, involved in nutrient absorption, and the follicle-associated epithelium (FAE), which contains M cells that play a crucial role in immune defense by sampling antigens.
The researchers found that Salmonella bacteria detect electrical fields in the FAE and move toward these openings, exploiting a process called galvanotaxis or electrotaxis.
“Our study found that this ‘entry point’ has electric fields that the Salmonella bacteria take advantage of to pass,” Min Zhao, senior author and UC Davis professor of ophthalmology and dermatology, said in the news release.
Interestingly, while E. coli clustered near the nutrient-absorbing villi, Salmonella gathered near the FAE.
Differing Reactions to Electric Cues
The study demonstrated that Salmonella and E. coli respond differently to bioelectric fields.
“Notably, the bioelectric field in the gut epithelia is configured in a way that Salmonellae take advantage of to be sorted to the FAE and less so for E. coli,” Sun added.
Unlike chemotaxis, where bacteria move in response to chemical signals, this study reveals an alternative pathway influencing bacterial movement.
Implications for Human Health
The discovery has significant implications for understanding and treating various diseases, including inflammatory bowel disease (IBD).
“This mechanism represents a new pathogen-human body ‘arms race’ with potential implications for other bacterial infections as well as prevention and treatment possibilities,” Zhao added.
By understanding these bioelectric activities, the researchers hope to develop better strategies to manage not just infections, but also chronic diseases linked to immune responses.
The UC Davis study, co-authored by Fernando Ferreira, Brian Reid, Kan Zhu and several others, opens new doors to exploring how gut electrical cues affect bacterial behavior and could pave the way for pioneering treatments in infectious disease and beyond.