SURFACE PROTEINS OF LACTIC ACID BACTERIA INTERFERE WITH THE BIOFILM FORMATION OF SALMONELLA

MERINO, LINA; TREJO, FERNANDO M.; DE ANTONI G.L; GOLOWCZYC, MARINA

Congreso; XII CONGRESO ARGENTINO DE MICROBIOLOGÍA GENERAL SAMIGE; 2017

Biofilms are composed of microorganisms attached to a substratum in which bacteria form structured communities immersed in a matrix composed mainly of polysaccharides, proteins and other macromolecules. The bacteria present in biofilms are more resistant to unfavorable environmental conditions and confer resistance to disinfectants, antibiotics and the host immune system. Salmonella is commonly associated with foodborne diseases, mainly related to the poultry industry, which produces the disease called salmonellosis. Since this pathogen is capable of forming biofilm, it is necessary to develop a biocontrol strategy to reduce the impact on public health and avian production. Lactic acid bacteria (LAB) may be used as an alternative to reduce the formation of biofilms of pathogens in the food industries.In this work we propose to study the surface proteins of lactic acid bacteria for the inhibition of the formation of Salmonella biofilm.The extraction of surface proteins from the Lb. kefiri CIDCA 83113, CIDCA 8321 and CIDCA 8344 and Lb. plantarum 83114 strains were used. For biofilm formation assays, Salmonella enterica serovar Gallinarum CIDCA 115 isolated from a poultry farm was used. Surface proteins of the LAB cultures were extracted with LiCl 5M. Biofilm formation assays were performed in 24-well plates. The surface proteins were pre-incubated on the plate for two hours before inoculation of Salmonella or co-incubated with pathogen. Plate was incubated for 48 hours at 28 °C. Detection of the surface proteins extracted was performed by electrophoretic run on polyacrylamide gel and the quantification was performed by the Bradford method.The majority of protein in the extracts of Lb. kefiri CIDCA 83113, CIDCA 8321 and CIDCA 8344 was the S-layer protein, while Lb. plantarum 83114 showed several protein bands without presence of S-layer protein. Pre-incubation with lactobacilli surface proteins decreased in all cases the formation of Salmonella biofilm determined by nutrient agar count. Co-incubation of different concentrations (10, 30 and 60 μg/ml) of Lb. kefiri CIDCA 8321 S-layer on the ability of Salmonella to form biofilm was also determined. It was observed that the presence of S-layer proteins decreases one or two orders of magnitude Salmonella counts in the biofilm and it was observed that this effect was dose- response. The surface proteins of lactic acid bacteria inhibit the development of Salmonella biofilm and could be an alternative to avoid possible contamination in poultry environments