“La shigellose kills around 200,000 people worldwide per yearincluding 65,000 children under the age of 5″, estimates the Institut Pasteur. This is a highly contagious diarrheal diseaseof which the transmission is fecal-oral (the person becomes infected in particular by eating food contaminated with feces).
Shigellosis can lead to short-lived diarrhea (3-4 days). However, treatment may sometimes be necessary. Indeed, in moderate to severe casesthe infection can lead to bloody diarrhea, as well as other complications. In these cases, antibiotics are used. However, according to a recent study, Shigella Sonnei bacteria, the most common in developed countries (including France), would be resistant to antibiotics. This worries the Institut Pasteur, which has been monitoring these bacteria for some time. The results of the study have been published January 26 in the magazine Nature and Communications.
Shigella bacteria: strong resistance to antibiotics
For this study, scientists from the Institut Pasteur analyzed more than 7,000 strains of Shigella Sonnei. They also relied on epidemiological information collected as part of the surveillance of the bacterium between 2005 and 2021.
They thus discovered a antibiotic resistance of the most widespread bacterium: “Researchers at the National Reference Center for Escherichia coli, Shigella and Salmonella at the Institut Pasteur who have been monitoring this bacterium on a national level for many years, have thus detected the appearance of strains of Shigella sonnei highly resistant to antibiotics“, explains the Pasteur Institute in its press release.
The strains considered to be ultra-resistant (XDR strains for extensively drug-resistant) were first identified in Shigella sonnei samples from 2015. “Scientists have found that the proportion of these XDR strains, which are resistant to virtually all antibiotics recommended for the treatment of shigellosis, increased significantly until reaching a peak in 2021: 22.3% of all strains of Shigella sonnei were highly resistant that year (corresponding to 99 cases)“, detail the scientists.
Shigellosis: two intravenous treatments remain effective
A sequencing analysis of the XDR strains allowed scientists to discover that they all belonged to “the same evolutionary line became resistant to a key antibiotic (ciprofloxacin) around 2007 in South Asia“. These strains then spread to several regions of the world, including France.
Currently, according to researchers, 2 antibiotics remain effective : carbapenems or colistin. These are 2 treatments used in severe cases and to be administered intravenously“which makes the treatment more aggressive with more complex follow-up in a hospital setting“, details the Pasteur Institute.
“Studies are still needed to better understand the different clinical forms of this infection and whether there are in particular asymptomatic forms allowing greater dissemination of the bacteria. Therapeutic trials are also essential to identify effective oral antibiotics to treat these strains of Shigella highly resistant“, conclude the experts from the Institut Pasteur.