The Role of Extracellular DNA in Salmonella Biofilms

Abstract

In the present study, we focus on the effect of eDNA on the initial bacterial adhesion, biofilm formation, and the mature biofilms of 17 different Salmonella serovars. We evaluated the roles of eDNA on the initial microbial adhesion, and found that some of Salmonella serotypes formed significantly more biomass in the presence of DNase I, during the early stages of biofilm formation at 28°C for 24 hours, while same strains were not produce biofilm at 37°C. We suggested that the reason for divesity among biofilm production abilities of different serovars may be due to the variability of gene expression levels at different growth temperatures. It was observed that eDNA had a notable negative effect on the initial attachment of these serovars. 45.8% of all pre-established biofilm samples of serovars were eradicated at high concentrations of DNase I (50 μg/mL). Our study highlights the serotype based role of eDNA in Salmonella strains. This report is one of the few that represents the inhibitive effect of eDNA on biofilm formation of Salmonella strains. Also, this is the fisrt evidence that eDNA has either inhibitive or stimulative effects dependind on the serovars.