'Exploding' genetically engineered probiotic strains could fight bacterial infections

These E. coli​ ​strains are already probiotic in nature and when they encounter the harmful ​Pseudomonas aeruginosa​, they explode and release a toxin that selectively kills the pathogen.

The researchers found that their engineered probiotic could fight the disease in both mice and worm models, though it was better at preventing infection than fighting an already established one.

Writing in the journal Nature Communications​, academics at the National University of Singapore said they had previously engineered a laboratory strain of Escherichia coli​ in such a way that, in the presence of the pathogen Pseudomonas aeruginosa​, the E. coli​ cells selectively kill the pathogen.

“Bacteria can be genetically engineered to kill specific pathogens or inhibit their virulence,”​ they stated.

“We previously developed a synthetic genetic system that allows a laboratory strain of Escherichia coli to sense and kill Pseudomonas aeruginosa in vitro.”​

Intestinal disorders

However, it was unclear whether this approach would work during an infection in an animal.

Matthew Chang and colleagues modified this genetic system and used it to engineer E. coli​ Nissle 1917, a probiotic shown to have beneficial effects on certain intestinal disorders.

The authors suggest that these engineered probiotic bacteria could be freely administered for their normal probiotic-associated benefits, while also potentially protecting against certain pathogens.

They wrote: “We tested the system in vivo using roundworm and murine infection models. In both systems, the engineered probiotic E. coli Nissle autonomously executes diagnostic and therapeutic activities that efficiently reduce a pre-colonized P. aeruginosa infection. ​

“Furthermore, the engineered probiotic strain exhibited prophylactic activity by conferring specific protection against P. aeruginosa infection.”​

Further studies will be needed to examine whether the findings can be translated to humans.

Source: Nature Communications​

DOI: ​10.1038/ncomms15028​

“Engineered probiotic Escherichia coli can eliminate and prevent Pseudomonas aeruginosa gut infection in animal models”.​

Authors; Matthew Chang, et al​

Probiota Asia 2017​ ​

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