Good news in research against cholera, which is currently resurgent in about thirty countries and is responsible for about 100,000 deaths a year worldwide. Recent work by a group from the Massachusetts Institute of Technology (MIT, Massachusetts) and published in Journal of the European Organization for Molecular Biology (EMBO) really opens the door to disease prevention.
Protective molecules based on sugars
It highlights a novel mechanism demonstrating that it is possible to prevent the production of the cholera causative agent, Vibrio cholerae, the toxin responsible for the severe diarrhea that causes the dehydration characteristic of the disease, which is sometimes fatal.
How ? Thanks to protective molecules based on glycan sugars contained in the mucus, the cell-free film covers most of the organs and plays a key role in the fight against microbes. Indeed, previous work by members of the MIT team has already shown that these glycans can deactivate other types of bacteria such as Pseudomonas aeruginosa or the yeast Candida albicans.
Cholera epidemics have become more numerous and serious
Here, in the specific case of cholera, researchers know that strains only become pathogenic when they are infected with a phage virus, CTX, that phage carries genes that code for cholera toxin, the toxin responsible for the symptoms. But for this to happen, the CTX phage must bind to a receptor on the bacterial surface known as the co-regulated toxin pilus (TCP).
In this new work, by creating purified glycans from the gastrointestinal tract of pigs, the scientists successfully demonstrated that they are able to suppress the bacteria’s ability to produce the TCP receptor so that the CTX phage can no longer infect it. Hence the idea, in the long term, to succeed in delivering glycans to the very site of infection, helping to strengthen the mucosal barrier and thereby preventing the symptoms of cholera, which affects up to 4 million people every year.
Thus, this new preventive approach will be added to the basic measures of hygiene, surveillance and improvement of water supply, while not forgetting vaccination in risk areas. However, please note that in October 2022 due to shortage of WHO vaccines in exceptional cases changed its vaccination strategy to one dose instead of two. Due to floods, droughts, conflicts, population movements and other factors that limit access to drinking water, cholera epidemics today have become more numerous, more widespread and more severe. Five years ago, this concerned less than 20 countries, in 2023 there will be 30.
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