Towards an understanding ofSalmonella entericaserovar Typhimurium persistence in swine

Abstract

AbstractSalmonella entericais an important food borne pathogen that is frequently carried by swine. Carrier animals pose a food safety risk because they can transmitS. entericato finished food products in the processing plant or by contamination of the environment. Environmental contamination has become increasingly important as non-animal foods (plant-based) have been implicated as sources ofS. enterica. The prevalence ofS. entericain swine is high and yet carrier animals remain healthy.S. entericahas developed a highly sophisticated set of virulence factors that allow it to adapt to host environments and to cause disease. It is assumed thatS. entericaalso has developed unique ways to maintain itself in animals and yet not cause disease. Here we describe our research to understand persistence. Specifically, data are presented that demonstrates that detection of most carrier animals requires specific stresses that causeS. entericato be shed from pigs. As well, we describe a phenotypic phase variation process that appears to be linked to the carrier state and a complex set of factors that control phenotypic phase variation. Finally, we describe how the composition of the gut bacterial microbiome may contribute to persistence and at the least howS. entericamight alter the composition of the gut bacterial microbiome.