Drug-Resistant Salmonella Strain Linked to West Africa
Researchers identified a ciprofloxacin-resistant Salmonella Typhi genotype in travelers returning from West Africa.
Updated on Sept. 21, 2026 in Diseases — General
Between 2021 and 2025, scientists detected a new multidrug-resistant genotype of Salmonella enterica serovar Typhi in travelers returning from West Africa. This specific strain, classified as genotype 2.3.1, has acquired genetic resistance to critical antibiotics.
Why it matters
The emergence of this strain complicates global efforts to treat typhoid fever, which caused an estimated 93,300 deaths worldwide in 2021. Genetic mutations now allow the bacteria to evade standard treatments like ciprofloxacin, increasing the risk for international travelers.
Of the 167 identified genotype 2.3.1 cases, 80.8 percent involved travel to Africa, with a median patient age of 28. The cohort was 64.7 percent female and 35.3 percent male.
The players
National Reference Center for Escherichia coli, Shigella, and Salmonella
This French institution provides surveillance and expert diagnostic services for enteric pathogens.
The details
The strain evolved through the acquisition of two multidrug-resistance plasmids and the chromosomal integration of the IncHI1 plasmid MDR region. A specific gyrA mutation encodes the bacteria's resistance to nalidixic acid and ciprofloxacin, which was confirmed through whole-genome sequencing.
Timeline
1950s: Sporadic antimicrobial resistance first detected in Salmonella Typhi.
1970s-1980s: Epidemic multidrug-resistant populations emerged.
2016-2025: French laboratory received 1,603 Salmonella Typhi isolates.
2021-2025: Genotype 2.3.1 strain detected in travelers.
The Big Picture
The discovery of genotype 2.3.1 follows a pattern of evolving resistance established by the epidemic multidrug-resistant populations of the 1970s and 1980s.
Travelers visiting West Africa should consult a healthcare provider regarding updated vaccination and antibiotic sensitivity profiles for typhoid fever. This strain significantly limits traditional treatment options, making medical screening essential for those reporting symptoms after travel.
The takeaway
Antibiotic resistance in Salmonella Typhi continues to evolve as bacteria acquire new genetic tools to survive standard medication. Preventing infection remains the most effective strategy for travelers heading to regions where resistant strains are circulating.
Further reading
Learn more about the latest findings in Diseases — General.
Source note: This article includes information reported by Cdc.
