Salmonella-specific transcriptional regulator affecting biofilm formation and virulence

VITOR-HOREN, L.; ECHARREN, M. L.; FIGUEROA, N. R.; SONCINI, F. C.

Paraná

Congreso; LIV Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2018

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Salmonellosis is among the most common foodborne diseases, with millions of human infections occurring worldwide every year. A key aspect ofSalmonella?s life cycle that contributes to its high prevalence is its ability to form biofilms, bacterial communities embedded in a selfproduced extracellular matrix that allows them to adhere to each other and to diverse surfaces. This multicellular behavior facilitates persistence and transmission between hosts, and survival in the environment. InSalmonella, the extracellular matrix is composed mainly by cellulose and curli fimbriae whose synthesis are controlled at transcriptional level through the expression of its master regulator, CsgD. Expression of this transcriptional activator is in turn finely regulated by several transcription factors that integrate different environmental signals. We identified a previously uncharacterizedSalmonella-specific transcription factor, MlrB, that affects biofilm-formation by controlling the induction of the Csg regulon, and hence the switching between planktonic and sessile lifestyles. We purified MlrB and determined that it expression is maximal under conditions relevant to the infection, which agrees with the regulation observed for members of the SPI-2 locus. We also established that MlrB is essential for intracellular survival in macrophages, allowing us to postulate it as a link between the biofilm formation and Salmonella pathogenesis