Spread ofSalmonella entericain the body during systemic infection: unravelling host and pathogen determinants

Abstract

Salmonella entericacauses a range of life-threatening diseases in humans and animals worldwide. Current treatments forS. entericainfections are not sufficiently effective, and there is a need to develop new vaccines and therapeutics. An understanding of howS. entericaspreads in tissues has very important implications for targeting bacteria with vaccine-induced immune responses and antimicrobial drugs. Development of new control strategies would benefit from a more sophisticated evaluation of bacterial location, spatiotemporal patterns of spread and distribution in the tissues, and sites of microbial persistence. We review here recent studies ofS. entericaserovar Typhimurium (S. Typhimurium) infections in mice, an established model of systemic typhoid fever in humans, which suggest that continuous bacterial spread to new infection foci and host phagocytes is an essential trait in the virulence ofS. entericaduring systemic infections. We further highlight how infections within host tissues are truly heterogeneous processes despite the fact that they are caused by the expansion of a genetically homogeneous microbial population. We conclude by discussing how understanding the within-host quantitative, spatial and temporal dynamics ofS. entericainfections might aid the development of novel targeted preventative measures and drug regimens.