Israeli Scientists Discover How E. coli Adapts to Infect Human Cells

Researchers at the Hebrew University of Jerusalem have identified a novel mechanism by which the dangerous bacterium E. coli attaches to human intestinal cells, potentially paving the way for new therapeutic approaches. Traditionally, E. coli uses tiny appendages to adhere to the intestinal lining, preventing it from being flushed out and enabling infection. However, atypical strains lacking these appendages have recently emerged, posing a significant challenge.

To understand how these atypical strains infect, the scientists simulated the attachment process in a laboratory setting. They engineered E. coli to lack its primary attachment mechanism and then selected for bacteria that could still bind to human cells. After only four selection cycles, the bacteria developed a potent new attachment capability.

This adaptation occurred through two main pathways. Some bacteria elongated significantly, increasing their surface area for contact. Others acquired genetic mutations in the FimH protein, located on the bacterial surface. These mutations allowed the FimH protein to bind much more strongly to human cell molecules, enhancing adhesion hundredsfold and increasing the bacteria's ability to inject toxins.

The findings, published in the journal Gut Microbes, were corroborated by analyzing the genomes of hundreds of E. coli strains from actual patients, confirming that these adaptive changes are prevalent in nature. Professor Ilan Rosenshine, a co-author, described the adaptation as akin to "losing a 'hook' and quickly learning to use a 'loop,'" emphasizing that bacteria can improve existing tools rather than inventing entirely new systems.

This discovery suggests a promising therapeutic strategy: instead of solely focusing on killing the bacteria, future treatments could target and block the FimH protein, thereby preventing the pathogen's attachment to the intestinal wall.