In recent years, the emergence of bacterial strains resistant to multiple drugs has become a global concern. One such strain is the Shigella sonnei strain, which has caused a number of outbreaks of gastrointestinal illness worldwide. Recently, the emergence of an extensively drug-resistant strain of Shigella sonnei in France has raised serious concerns among public health officials. This article will discuss the characteristics of this strain, its potential impact on public health, and the measures being taken to control its spread.
Shigellosis, a highly contagious diarrheal disease caused by Shigella bacteria, is becoming a major concern, not only in industrializing countries but also in industrialized countries. A recent study by scientists from the French National Reference Center for Escherichia coli, Shigella and Salmonella at the Institut Pasteur reveals that extensively drug-resistant (XDR) strains of Shigella sonnei have emerged. The bacterial genome sequencing and case studies suggest that these strains, originating in South Asia, are mostly spread among men who have sex with men (MSM). The study is based on an analysis of over 7,000 S. sonnei isolates and epidemiological information gathered by CNR-ESS, covering the years 2005-2021.
Shigellosis is highly contagious and spreads through fecal-oral transmission. Among various types of Shigella, Shigella sonnei is the species that mainly circulates in industrialized countries. It causes short-term diarrhea, which usually resolves on its own. However, antibiotic treatment is necessary for moderate to severe cases or to prevent person-to-person transmission in epidemic situations. The emergence of antibiotic resistance mechanisms by Shigella bacteria seriously restricts therapeutic options.
According to the study, XDR isolates were first identified in France in 2015, and their proportion increased significantly, reaching 22.3% of all S. sonnei isolates in 2021. Genome sequencing revealed that all these French XDR strains belonged to the same evolutionary lineage, which became resistant to a key antibiotic in around 2007 in South Asia. In several geographical regions, including France, these strains then acquired different plasmids coding for resistance to other first-line antibiotics.
XDR isolates were observed in various contexts, including travelers returning from South Asia or South-East Asia and during an outbreak at a school in 2017. However, the most widespread XDR strains were found to be circulating among MSM, who were infected by an epidemic clone that has been spreading throughout Europe since 2020. This subgroup of XDR strains circulating in MSM accounted for 97% of XDR strains in France in 2021.
The study warns that clinicians and laboratories must take note of this observation when testing for sexually transmitted infections in MSM, and systematic antibiograms should be performed if a Shigella strain is isolated to improve treatment for patients infected with XDR strains. Further research is needed to understand the different clinical forms of infection and identify effective oral antibiotics for treating these XDR Shigella strains. Therapeutic trials would be vital to combat this emerging problem.
In conclusion, this study highlights the need for increased surveillance of the antimicrobial resistance of Shigella and other pathogens. It also emphasizes the importance of developing strategies to curb the emergence and spread of XDR strains, which pose a severe threat to public health, especially among vulnerable groups.
In conclusion, the emergence of extensively drug-resistant Shigella sonnei strain in France highlights the pressing need for continued monitoring of infectious diseases and the development of new antibiotics. As the world becomes more interconnected, these multidrug-resistant strains can quickly spread beyond borders and become a global threat. The medical community must work together to implement effective infection control measures and ensure the responsible use of antibiotics. Only a united effort can curb the spread of these deadly infections and safeguard public health. Let us remain vigilant and prepared for any future outbreaks.
