It bears the name of Shigella dysenteriae. The bacteria responsible for dysentery, an infectious disease causing diarrheabloody, was first identified in Japan in 1897. Yet it is originally from Europe. A collaboration of several international institutions, headed by the Institut Pasteur (Paris), makes it possible to retrace the history of this bacillus and to predict its evolution. This vast study, published this Monday, March 21, 2016 in the journal Nature Microbiology and relayed byPastor Institute, was based on the analysis of the genomes of more than 330 strains of the bacterium, ranging from 1915 to 2011. The oldest strains were isolated from soldiers of the First World War. 35 institutes collaborated in the study, across 66 countries.
A European home, conquering all continents
Thanks to the decryption of the genes of this bacillus, the researchers were able to trace its path. Contrary to what was thought until now, the bacillus would originate in Europe and would have already raged in 1740. It could also be responsible for the epidemics of bloody diarrhea recorded in the 18th and 19th centuries in Western and Western Europe. Nord, which had caused more than 200,000 deaths in France and more than 35,000 in Sweden. Then, between 1889 and 1903, Shigella dysenteriae took advantage of migratory flows and colonization to establish itself in America, Africa and Asia. It then benefited from the poor sanitary and hygienic conditions of the two world wars to conquer central Europe, before disappearing from this continent. However, it continues to spread in Central America, Africa and Asia where it causes regular and violent epidemic outbreaks.
99% of strains resistant to antibiotics
The scientific investigation also looks into the future of the bacillus and points to the risks associated with bacterial resistance. In fact, in just 25 years (between 1965 and 1990), 99% of strains of Shigella dysenteriae have developed resistance to antibiotics. “Researchers worry that the emergence of bacteria resistant to the latest classes of antibiotics is inevitable today“worries the Institut Pasteur in a press release.”However, this pessimism may be tempered by a greater rarity of infection since 2010, including in South Asia and Africa.“reassures the Institute.
But its presence in field analyzes, particularly in Africa, shows that the dysentery bacillus “still circulates quietly and could again be responsible for epidemics if it were to encounter favorable circumstances, such as a large gathering of people without access to drinking water or treatment of human waste“, according to Doctor François-Xavier Weill, head of the Enteric Pathogenic Bacteria unit at the Institut Pasteur and coordinator of this study. Faced with this epidemic risk accentuated by the generalization of bacterial resistance, find an effective vaccine against dysentery would be a safer method of control than resorting to antibiotics.
Currently, the Institut Pasteur and the National Institute for Health and Medical Research (Inserm) are developing an oral vaccine against this infection.
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