Butyrate decreases Campylobacter jejuni motility and attachment partially through influence on LysR expression

Abstract

The food pathogen Campylobacter jejuni both colonizes the lower intestines of poultry and infects the lower intestines of humans. The lower intestines of both poultry and humans are also home to a wide range of commensal organisms which compete with an organism like C. jejuni for space and resources. The commensal organisms are believed to protect humans against infection by pathogens of the digestive tract like C. jejuni. The short chain fatty acid (SCFA) butyrate is a metabolite commonly produced by commensal organisms within both the poultry and human digestive tract. We investigated the affect that physiologically relevant concentrations of butyrate have on C. jejnui. Butyrate at concentrations of 5 and 20 mM negatively impacted C. jejuni motility and attachment. These two traits are believed important for C. jejunis ability to infect the lower intestines of humans. Additionally, 20 mM butyrate concentrations were observed to influence the expression of a range of different Campylobacter proteins. Constitutive expression of one of these proteins, LysR, within a C. jejuni strain partially lessened the negative influence butyrate had on the bacterias motility. ImportanceResearch studies on the short chain fatty acid, butyrate, have produced evidence for it both negatively and positively impacting Campylobacter jejunis colonization of poultry or infection of the human intestinal tract. There is significant value in clarifying if butyrate has potential as an intervention agent capable of interfering in the virulence process of C. jejuni. The results presented, show that butyrate, at physiological levels, negatively impacts C. jejuni motility and attachment, two important factors in the virulence process. Additionally, a proteomic analysis of butyrates influence on C. jejuni, identified that the expression of the transcriptional factor, LysR, was repressed in the presence of butyrate. Overexpression of the lysR gene restored some motility in the presence of butyrate suggesting this factor had a positive influence on the flagella necessary for C. jejunis movement.