Genome-wide fitness analysis identifies genes required for growth and macrophage infection by African and global epidemic pathovariants of Enteritidis.

Enteritidis is the second most common serovar associated with invasive non-typhoidal (iNTS) disease in sub-Saharan Africa. Previously, genomic and phylogenetic characterization of . Enteritidis isolates from the human bloodstream led to the discovery of the Central/Eastern African clade (CEAC) and West African clade, which were distinct from the gastroenteritis-associated global epidemic clade (GEC).

The use of chicken and insect infection models to assess the virulence of African Salmonella Typhimurium ST313.

Over recent decades, Salmonella infection research has predominantly relied on murine infection models. However, in many cases the infection phenotypes of Salmonella pathovars in mice do not recapitulate human disease. For example, Salmonella Typhimurium ST313 is associated with enhanced invasive infection of immunocompromised people in Africa, but infection of mice and other animal models with ST313 have not consistently reproduced this invasive phenotype.

Adding function to the genome of African Salmonella Typhimurium ST313 strain D23580.

Salmonella Typhimurium sequence type (ST) 313 causes invasive nontyphoidal Salmonella (iNTS) disease in sub-Saharan Africa, targeting susceptible HIV+, malarial, or malnourished individuals. An in-depth genomic comparison between the ST313 isolate D23580 and the well-characterized ST19 isolate 4/74 that causes gastroenteritis across the globe revealed extensive synteny. To understand how the 856 nucleotide variations generated phenotypic differences, we devised a large-scale experimental approach that involved the global gene expression analysis of strains D23580 and 4/74 grown in 16 infection-relevant growth conditions.

Role of a single noncoding nucleotide in the evolution of an epidemic African clade of .

serovar Typhimurium ST313 is a relatively newly emerged sequence type that is causing a devastating epidemic of bloodstream infections across sub-Saharan Africa. Analysis of hundreds of genomes has revealed that ST313 is closely related to the ST19 group of Typhimurium that cause gastroenteritis across the world. The core genomes of ST313 and ST19 vary by only ∼1,000 SNPs.