Genomic surveillance reveals multiple independent transmissions and plasmid-mediated drug resistance in pediatric typhoid isolates, highlighting regionally distinct bacterial evolution.
Key Points
To determine the phylogenetic origins and molecular drivers of antimicrobial resistance among Salmonella enterica serovar Typhi isolates causing pediatric bacteremia in Nigeria.
Conducted whole-genome sequencing on N=128 S. Typhi blood culture isolates collected during pediatric surveillance across two sites in Nigeria.
Assessed global phylogenetic relationships and identified specific molecular determinants of antimicrobial resistance, including plasmid replicon types.
Identified multiple distinct S. Typhi lineages connected to regional African clusters, indicating several independent introductions into the country rather than a single outbreak.
Found no evidence of the rapidly expanding multidrug-resistant clade 4.3.1 (H58) commonly reported in Asia and East Africa.
Detected frequent antimicrobial resistance mediated by diverse mobile genetic elements, including the IncHI1 plasmid, confirming independent evolution of multidrug-resistant typhoid.