The first extensively drug-resistant (XDR) strains of Salmonella Typhimurium, a pathogen which is responsible for millions of bloodstream infections per year in sub-Saharan Africa, have been identified in the Democratic Republic of Congo (DRC). Drug-resistance has increased in successive groups of S. Typhimurium over time. These new strains are resistant to all but one of the commonly available drugs in the DRC, with one sample showing reduced susceptibility to this final antibiotic.

Salmonella bacteria (red)/National Institute of Allergy and Infectious Diseases (NIAID)

The study, published Thursday in Nature Communications, was conducted by researchers from the Institute of Tropical Medicine (ITM) in Antwerp, the Institut National de Recherche Biomédicale (INRB) in the DRC, the Wellcome Sanger Institute, the University of Cambridge and their collaborators. The findings suggest that S. Typhimurium has evolved in sub-Saharan Africa in the past decades and continues to do so. A multifaceted approach will be needed to track and control the spread of XDR Salmonella, including further microbiological and genomic surveillance.

Most Salmonella infections result in symptoms associated with food poisoning. While unpleasant, symptoms are not life-threatening in the vast majority of cases. But in sub-Saharan Africa, Salmonella such as S. Typhimurium can cause infections of the blood, known as invasive non-typhoidal Salmonella (iNTS) infections.

Every year, iNTS infections are estimated to affect 3.4 million people and result in 681,316 deaths globally, of which the majority are caused by S. Typhimurium. The containment and treatment of iNTS infections in places like the DRC is complicated by limited access to healthcare, infrastructure challenges and weakened immunity, with children under five years of age particularly at risk.

Read more at Wellcome Sanger

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