Diarrhea-causing bacterium Clostridium difficile is evolving into two different species, and one of the bacterial group is highly readjusted to spread in hospitals
Diarrhea-causing bacterium Clostridium difficile is evolving into two different species, and one of the bacterial group is highly readjusted to spread in hospitals. Team of researchers at the Wellcome Sanger Institute, London School of Hygiene & Tropical Medicine and collaborators identified genetic changes in the newly-emerging species that allow it to thrive on the Western sugar-rich diet, evade common hospital disinfectants and spread easily. Able to cause debilitating diarrhea, they estimated this emerging species started to appear thousands of years ago and account for over two-thirds of healthcare C. difficile infections.
‘The team of researchers have discovered that this emerging species, named C. difficile clade A, made up approximately 70 per cent of the samples from hospital patients.’
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Published in Nature Genetics today (12 August), the largest ever genomic study of C. difficiles hows how bacteria can evolve into a new species, and demonstrates that C. difficile is continuing to evolve in response to human behavior. The results could help inform the patient about diet and infection control in hospitals. Read More..
C. difficile bacteria can infect the gut and are the leading cause of antibiotic-associated diarrhea worldwide*. While someone is healthy and not taking antibiotics, millions of 'good' bacteria in the gut keep the C. difficile under control. However, antibiotics wipe out the normal gut bacteria, leaving the patient vulnerable to C. difficile infection in the gut. This is then difficult to treat and can cause bowel inflammation and severe diarrhea.
Often found in hospital environments, C. difficile forms resistant spores that allow it to remain on surfaces and spread easily between people, making it a significant burden on the healthcare system.
To understand how this bacterium is evolving, researchers collected and cultured 906 strains of C. difficile isolated from humans, animals, such as dogs, pigs and horses, and the environment. By sequencing the DNA of each strain, and comparing and analyzing all the genomes, the researchers discovered that C. difficile is currently evolving into two separate species.
Dr. Nitin Kumar, a joint first author from the Wellcome Sanger Institute, said: "Our large-scale genetic analysis allowed us to discover that C. difficile is currently forming a new species with one group specialized in spreading in hospital environments. This emerging species has existed for thousands of years, but this is the first time anyone has studied C. difficile genomes in this way to identify it. This particular bacteria was primed to take advantage of modern healthcare practices and human diets before hospitals even existed."
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Dating analysis revealed that while C. difficile Clade A first appeared about 76,000 years ago, the number of different strains of this started to increase at the end of the 16th Century, before the founding of modern hospitals. This group has since thrived in hospital settings with many strains that keep adapting and evolving.
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Prof Brendan Wren, an author from the London School of Hygiene & Tropical Medicine, said: "This largest ever collection and analysis of C. difficile whole genomes, from 33 countries worldwide, gives us a full new understanding of bacterial evolution. It reveals the importance of genomic surveillance of bacteria. Ultimately, this could help understand how other dangerous pathogens evolve by adapting to changes in human lifestyles and healthcare regimes, which could then inform healthcare policies."
Source-Eurekalert