Atypical Salmonella enterica Serovars in Murine and Human Macrophage Infection Models.

Nontyphoidal species are globally disseminated pathogens and are the predominant cause of gastroenteritis. The pathogenesis of salmonellosis has been extensively studied using murine models and cell lines, typically challenged with serovar Typhimurium. Although serovars Enteritidis and Typhimurium are responsible for most of the human infections reported to the Centers for Disease Control and Prevention (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 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 infections, whereas differentiated human THP-1 macrophages allowed these isolates to be further characterized in a more human-relevant context.