When harmful bacteria like E. coli enter the digestive tract, the gut usually fights back by flushing out infected cells before the infection can spread. But some bacteria have found a way to stop that defense in its tracks.
A new study in Nature from Oregon Health & Science University (OHSU) and Genentech reveals how a particularly dangerous strain of E. coli, the kind that can cause bloody diarrhea, uses a clever trick to take over the gut.
Researchers discovered that the bacteria inject a protein called NleL into gut cells. This protein disables two key enzymes that normally help infected cells break away and get expelled. Without that process, the infected cells stay put, giving the bacteria more time to grow and spread.
“This study shows that pathogenic bacteria can block infected cells from being pushed out,” said Isabella Rauch, Ph.D., senior author and associate professor at OHSU. “It’s a completely different strategy from what we’ve seen before.”
The finding helps explain why some infections are harder to shake and could lead to new treatments that stop bacteria from spreading without using antibiotics.
“By understanding how bacteria bypass our body’s defenses, scientists could design anti-virulence therapies that don’t rely on antibiotics,” Rauch said. “That’s really important, especially as antibiotic resistance continues to rise.”
The study also offers insight into gut health beyond foodborne illness. The same cellular process that helps clear infection can go into overdrive in conditions like inflammatory bowel disease, weakening the gut barrier over time. Understanding both extremes could help scientists find new ways to protect and repair the gut lining.
Researchers note that these findings come at an important time. Severe E. coli infections can be especially dangerous for young children, and factors like climate change and weakened food safety systems may make such outbreaks more common.
The research was supported by the National Institutes of Health and conducted by OHSU in collaboration with Genentech, a member of the Roche Group.