E. coli engineered from stool samples can survive the hostile gut environment long enough to treat disease

Scientists have long tried to introduce genetically engineered bacteria into the gut to treat diseases. In the past, these attempts have focused on engineering common lab strains of E. coli, which cannot compete with the native gut bacteria that are well adapted to their host.

Now, a group of researchers from the University of California, San Diego, successfully engineered E. coli collected from both human and mice gut microbiomes and showed that they have the potential to treat diseases such as diabetes.

"All I can say to the non-native bacteria is good luck. The gut microbiome is very dynamic and is constantly changing, making things even harder for the non-native bacteria," says Amir Zarrinpar, a gastroenterologist at UC San Diego Health and the senior researcher of the paper. "It is challenging for bacteria that have never lived inside of a mammal before to now go into the gut microbiome jungle with all of these hostile conditions that are geared towards preventing bacterial invaders from taking hold."

The group devised a solution to this problem by directly engineering E. coli collected from the hosts. "Bacteria in our body are adapted to each one of us specifically: the kind of foods we eat, the common stresses our body experiences or induces, and our genetic background," says Zarrinpar. "This constantly fluctuating environment is their normal." This is a big advantage for native bacteria and makes them ideal candidates for engineering.

"We have engineered these bacteria to become factories that can live in our microbiome and potentially produce medicines," says Zarrinpar. "We know that E. coli can pick up pathogenic genes and cause disease, and now we're just realizing that if we put a beneficial gene in, it can help us to treat chronic diseases, maybe even cure some of them."

Image source: Thom Leach.