A life-threatening intestinal bacterium becomes more resistant and diffuses better in hospitals

An international group of scientists discovered that the Clostridium difficile bacteria, badociated with intestinal infections, would evolve into a more resilient and expanding species, mainly in hospitals.

According to a study. published this week in the journal Nature Genetics, the researchers conducted a full scale genomic badysis of 906 strains of this isolated bacillus from humans, animals – such as dogs, pigs and horses – and the environment. After sequencing the DNA of each of the samples and comparing their genomes, it was concluded that "C. difficult 'evolves in two distinct species .

"This collection, the largest genome complete of" difficult C. "from 33 countries gives us a complete new understanding of bacterial evolution," states the Professor Brendan Wren, who collaborated in the badysis.

The emerging species was located in 70% of hospitalized patient samples and is characterized by a genetic modification allowing it to metabolize monosaccharides: tests on mice showed that they colonized better the hosts whose diet was enriched in sugar . They have also developed genes involved in spore formation that give them greater resistance to common hospital disinfectants that can be multiplied more easily in this environment.

"This species has existed for thousands This particular bacterium appeared to take advantage of modern medical care practices and the human diet even before there were hospitals", explains Nitin Kumar, lead author of the study and member of the Sanger Institute in Cambridge (United Kingdom), who is dedicated to genomics and genetics research.

The & # 39; C. difficult is part of the normal intestinal microbiota of a healthy human being. However, is the leading cause of antibiotic-badociated diarrhea because the prolonged use of these drugs eliminates saprophytic flora and makes the bowel vulnerable to this microorganism. In addition to severe diarrhea can cause up to serious colitis with risk of death . Patients hospitalized for long periods are more likely to be colonized.

A New Approach

In this sense, Trevor Lawley, co-author of the study, believes that the discovery provides tools to focus the fight against this opportunistic pathogen by altering dietary habits. and looking for new alternatives outside of current standards for the use of antiseptics and disinfectants.

"This could help to understand how other dangerous pathogens evolve by adapting to lifestyle changes and health care regimes," Brendan Wren concludes.