The whole-genome sequencing of a global collection of Salmonella Typhimurium isolates is reported in this week’s issue of Nature Genetics.
Salmonella infections are classified as typhoidal or non-typhoidal (NTS). Salmonella Typhimurium is closely associated with invasive NTS in sub-Saharan Africa, which is common in children with malnutrition, severe anemia, malaria or HIV and HIV-infected adults.
Gordon Dougan and colleagues sequenced the genomes of 179 Salmonella Typhimurium isolates, including 129 diverse sub-Saharan African isolates associated with invasive disease. They show that the majority of isolates originate from two very closely related lineages, and estimate that they emerged ~52 and ~35 years ago, in close association with the current HIV pandemic. The similarity between the two lineages is in contrast to the genetically diverse Salmonella Typhimurium isolates outside sub-Saharan Africa.