Drug-Resistant Salmonella Strain Emerged in West Africa
A new multidrug-resistant Salmonella Typhi genotype has been identified in travelers returning from West Africa.
Updated on Sept. 21, 2026 in Diseases — General
Between 2021 and 2025, researchers identified a multidrug-resistant Salmonella enterica serovar Typhi genotype 2.3.1 strain among international travelers. This emerging strain was detected in patients who had recently returned from travels in West Africa.
Why it matters
The emergence of this strain complicates treatment for typhoid fever, a condition that accounted for an estimated 7.1 million cases and 93,300 deaths globally in 2021. Identifying such resistant genotypes is critical for informing travel medicine and local clinical care strategies.
Researchers analyzed 1,603 Salmonella Typhi isolates collected between 2016 and 2025, identifying 167 cases of genotype 2.3.1 through whole-genome sequencing. The median age of these patients was 28, with 80.8% reporting travel to Africa.
The players
National Reference Center for Escherichia coli, Shigella, and Salmonella
A French public health laboratory that conducts surveillance and genomic characterization of bacterial enteric pathogens.
The details
The strain acquired resistance through the acquisition of two multidrug-resistant (MDR) plasmids and the chromosomal integration of the IncHI1 plasmid. A specific gyrA mutation further encodes resistance to nalidixic acid and ciprofloxacin, which are standard antibiotics for managing salmonella infections. Conventional microbiologic examination confirmed these patterns, which mirror evolutionary adaptations seen in other resistant typhoid populations.
Timeline
1950s: Sporadic antimicrobial resistance was first detected in Salmonella Typhi.
1970s-1980s: Multidrug-resistant populations began to emerge globally.
2016-2025: A French laboratory received 1,603 total Salmonella Typhi isolates.
2021-2025: The genotype 2.3.1 strain was identified in returning travelers.
Health Landscape
The emergence of genotype 2.3.1 follows a pattern of increasing resistance in Salmonella Typhi, which has been monitored since the first detected cases of sporadic resistance in the 1950s. This finding highlights how genomic adaptation continues to complicate global typhoid management efforts.
Travelers planning visits to West Africa should consult a travel clinic to discuss current health risks and vaccine recommendations. If you develop a fever or gastrointestinal symptoms after returning from travel, notify your physician of your travel history to assist in proper diagnostic testing.
The takeaway
This resistant genotype represents a continued evolution in how typhoid bacteria respond to antibiotic treatments. Travelers should maintain high awareness of food and water safety in endemic regions and discuss any post-travel illnesses with their doctor.
Further reading
For more information on managing enteric infections and global health trends, visit Diseases — General.
Source note: This article includes information reported by Cdc.
