Submitted to: Infection and Immunity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/11/2001
Publication Date: 7/20/2001
Citation: Allen, C.A., Cray, P.J., Vasquez-Torres, A., Suyemoto, M., Altier, C., Feng, F.C., Libby, S.J. 2001. In vitro and in vivo assessment of Salmonella enterica serovar Typhimurium dt104 virulence. Infection and Immunity. 69:(7)4673-4677. Interpretive Summary: Salmonella are bacteria that can cause food-borne illness. One specific type of Salmonella, Salmonella typhimurium DT104, has developed resistance to five different antimicrobials, some of which are used in humans to treat severe illness. Additionally, infection with Salmonella typhimurium DT104 has been associated with observed increases in the severity of the illness in both humans and animals. This increase in illness was thought to be particular to this strain and its ability to resist killing by antimicrobials was thought to play a role in this increased illness. We used a mouse model, as well as laboratory assays, to determine if this strain caused more illness and was more invasive for cells than a strain of Salmonella which has been well studied and is known to cause illness in mice and invade cells. We did not observe any increase in severity of the illness, or death of the cells, for this particular Salmonella strain when compared to other known strains. Additionally, this specific Salmonella did not preferentially invade cells. This suggests that there may be other mechanisms that may be causing the observed increase in morbidity and mortality. Additional studies are being planned to determine if concurrent treatment with antimicrobials during infection increases illness.
Technical Abstract: Multi-drug resistant Salmonella typhimurium DT104 has become a widespread cause of human and animal infection in Europe and North America. In this study, an assessment of the ability of S. typhimurium DT104 to invade epithelial cells, survive in peritoneal macrophages or cause lethal infection of genetically-resistant or -susceptible mice did not reveal evidence of enhanced nor reduced virulence when compared with ATCC S. typhimurium strain 14028s.