Effect of small chain N acyl homoserine lactone quorum sensing signals on biofilms of food-borne pathogens

Abstract

Quorum sensing or cell to cell communication which includes inter- and intra-cellular communication has been implicated in the production of virulence factor and formation of biofilm in food-borne pathogens. In the present study, the effect of quorum sensing signals on the biofilms of food-borne pathogens has been elucidated. N-butryl homoserine lactone and N-hexanoyl homoserine lactone belonging to acyl homoserine lactone (AHL) family of signaling molecules were investigated for their effect on the biofilm formation (attachment and exopolymeric substance production) in the food-borne pathogens Escherichia coli, Salmonella enterica serovar Typhimurium and Vibrio parahemolyticus. The signaling molecules at a concentration of 1 µM were capable of increasing biofilm formation in all the tested pathogens. There was an increase in the attachment of the bacterial cells and biomass as observed by microtiter plate assay and exopolymeric substances production in the biofilms in presence of the AHLs. Further, it needs to be elucidated if the effect of AHLS on the biofilms of E. coli and S. enterica serovar Typhimurium is SdiA dependent.

Keywords: Biofilms; Food-borne pathogens; N acyl homoserine lactones; Quorum sensing.

Fig. 1

a Effect of AHLs (C4-HSL and C6-HSL) on biofilm formation in S. enterica serovar Typhimurium and V. parahemolyticus assessed by CV-MTP method. b Effect of AHLs (C4-HSL and C6-HSL) on EPS production in biofilms of S. Typhimurium and V. parahemolyticus assessed by ruthenium red technique