Scientific News

Bacterium that causes diarrhea is evolving to take advantage of hospital environments

The adaptation to the environment and therefore also to the action of contrast put in place by human beings is refined generation after generation in bacteria. A new study, conducted by a group of researchers from the Wellcome Sanger Institute and the London School of Hygiene and Tropical Medicine, confirms this.

The researchers this time studied the effects of the Clostridium difficile bacterium on the intestine. These bacteria can infect it and represent one of the main causes of antibiotic-associated diarrhea in humans.

In fact, when certain antibiotics are not taken, millions of other bacteria in the human intestine keep Clostridium difficile under control. However, with antibiotics many of the good bacteria are eliminated and this leaves the person vulnerable to the action of Clostridium difficile. The latter, in fact, is very difficult to treat taken individually as a species.

Precisely for the reasons mentioned above, this bacterium thrives in hospitals where, of course, antibiotics are for daily use. The researchers found that it is evolving into two separate species. The new species would have deviated towards a new evolutionary line for two reasons: to adapt to the diets of human beings increasingly characterized by sugar intake and to adapt to health practices and hospital environments.

In fact, it is developing more resistant spores that allow it to stay alive longer when placed on surfaces, which naturally facilitates its diffusion among people.

Researchers analyzed 906 Clostridium difficile strains taken from the body of people or animals or from the environment in the laboratory. They sequenced their DNA and then compared it to find that it is evolving into two separate species.

Nitin Kumar, the study’s first author, explains this in a press release published on the Sanger Institute website: “Our large-scale genetic analysis has allowed us to discover that C. difficile is currently forming a new species with a specialized group in the diffusion in hospital environments. This emerging species has existed for thousands of years, but this is the first time that someone has studied C. difficile genomes in this way to identify it. This particular bacterium was triggered to exploit modern health practices and human diets, even before hospitals existed.”

This study confirms how bacteria can evolve in relation to human behavior.