Scientists hack one of the most common bacteria in human intestines

One of the most common bacteria in the human gut, Bacteroides thetaiotaomicron, can now be engineered with new functions and re-introduced into the intestinal tract of a mouse. 

The work is a starting point for designing microbes that could eventually deliver drugs or detect long-term changes in the intestines that lead to inflammatory bowel disease or other illnesses.

The idea to bioengineer bacteria for therapeutic purposes isn't new, but not all bacteria are suited for the same tasks. Last year, Harvard scientists created E. coli that could be consumed by a mouse to sense conditions in the gut. However, one challenge with E. coli is that it is not present in the gut at high levels.

The MIT group, led by synthetic biologists Timothy K. Lu and Christopher Voigt, saw that Bacteroides had the potential to express genes on demand. Not to mention, as a commensal bacteria, it has stable, long-term interactions with human cells and other microbes in the intestines. This means a designer bacteria and its offspring would be able to stick around for a while.

"We took a lot of the tools that people are already using in other organisms, (e.g., promoters, ribosome-binding sequences, memory switches, CRISPR interference) and demonstrated that you could port all of these over into Bacteroides and get them working," says Lu, study senior author and a biological and electrical engineer at MIT. "We then showed that genetic devices could be implemented in the bacteria and be shown to function in the context of the mouse gut microbiome."