Atypical Salmonella enterica serovars in murine and human infection models: Is it time to reassess our approach to the study of salmonellosis?

Nontyphoidal Salmonella
species are globally disseminated pathogens and the predominant
cause of gastroenteritis. The pathogenesis of salmonellosis has been
extensively studied using in vivo murine models and cell lines typically
challenged with Salmonella Typhimurium. Although serovars
Enteritidis and Typhimurium are responsible for the most of human
infections reported to the CDC, several other serovars also contribute to
clinical cases of salmonellosis. Despite their epidemiological importance,
little is known about their infection phenotypes. Here, we report the virulence
characteristics and genomes of 10 atypical S. enterica serovars linked
to multistate foodborne outbreaks in the United States. We show that the murine
RAW 264.7 macrophage model of infection is unsuitable for inferring
human relevant differences in nontyphoidal Salmonella infections whereas
differentiated human THP-1 macrophages allowed these isolates to be further
characterised in a more relevant, human context.