Control of biofilm formation by Salmonella-specific transcriptional regulators

FIGUEROA, N. R.; HUMBERT, M. V.; CHECA, S. K.; SONCINI, F.C.

Rosario

Congreso; L Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2014

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Bacterial biofilms are a group of cells physically attached to each other and embedded in a self-produced extracellular matrix. Biofilm-formation by pathogenic bacteria has become a major concern in modern medicine. In particular, this multicellular behavior allows Salmonella to survive hostile environmental conditions and confers resistance to both host defenses and antimicrobial agents, contributing to the prevalence of this food-borne pathogen. The transition between planktonic and sessile lifestyles in Salmonella is controlled at the transcriptional level by CsgD, the master regulator that activates the synthesis of the major components of the extracellular matrix, cellulose and curli fimbriae. Expression of csgD is in turn finely controlled by several transcription factors that integrate different environmental signals. Based on in silico analysis we identified new Salmonella-specific transcription factors that affect biofilm-formation. Deletions, as well as overexpression of the genes coding for these factors in different genetic backgrounds provoked marked differences in motility, resistance to antibiotics and the development of characteristic biofilm morphotypes of this species, as well as on the expression of csgD. Our results demonstrate that under specific conditions these Salmonella-specific TFs are responsible for the establishment of a community lifestyle.