Journal of Microbial & Biochemical Technology

Fever-like temperature is a virulence regulatory cue controlling the motility and host cell entry of typhoidal Salmonella

World Congress and Expo on Applied Microbiology

August 18-20, 2015 Frankfurt, Germany

Dana Elhadad1,2, Michael McClelland3, Galia Rahav1,2 and Ohad Gal-Mor1,2

1Sheba Medical Center, Israel 2Tel Aviv University, Israel 3University of California, USA

Scientific Tracks Abstracts: J Microb Biochem Technol

Abstract:

Human infection with typhoidal Salmonella serovars causes a febrile systemic disease, termed enteric fever. Here we establish that in response to a temperature equivalent to fever (39°C�??42°C) Salmonella enteric serovars Typhi, Paratyphi A, and Sendai significantly attenuate their motility, epithelial cell invasion, and uptake by macrophages. Under these fever-like conditions, the residual epithelial cell invasion of S. paratyphi A occurs in a type III secretion system (T3SS) 1�??independent manner and results in restrained disruption of epithelium integrity. The impaired motility and invasion are associated with down-regulation of T3SS-1 genes and class II and III (but not I) of the flagella-chemotaxis regulon. In contrast, we demonstrate up-regulation of particular Salmonella pathogenicity island 2 genes (especially spiC) and increased intraepithelial growth in a T3SS-2�??dependent manner. These results indicate that elevated physiological temperature is a novel cue controlling virulence phenotypes in typhoidal serovars, which is likely to play a role in the distinct clinical manifestations elicited by typhoidal and non-typhoidal salmonellae.