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

Authors: Gunther, Nereus - Jack; Nunez, Alberto; Bagi, Lori; Abdulwakeel, Aisha; Ream, Amy; Liu, Yanhong; Uhlich, Gaylen

Submitted to: Food Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/30/2023
Publication Date: 6/1/2023
Citation: Gunther, N.W., Nunez, A., Bagi, L.K., Abdul Wakeel, A.Y., Ream, A.R., Liu, Y., Uhlich, G.A. 2023. Butyrate decreases Campylobacter jejuni motility and biofilm partially through influence on LysR expression. Food Microbiology. https://doi.org/10.1016/j.fm.2023.104310.
DOI: https://doi.org/10.1016/j.fm.2023.104310

Interpretive Summary: Campylobacter is the most common cause of bacterial foodborne gastrointestinal disease. The most common source of Campylobacter contamination in the food supply is found in poultry products, and this is because Campylobacter commonly colonizes the lower intestinal tract of chickens. When causing disease in humans, Campylobacter also infects the lower intestines. Both the lower intestines of chickens and humans are also colonized by harmless bacteria that are believed to be protective against disease causing bacteria like Campylobacter. The helpful bacteria in the lower intestines commonly secrete substances known as short chain fatty acids, one of which is called butyrate. Other labs have suggested that butyrate might have a negative influence on Campylobacter and make it difficult for the bacteria to colonize chickens; while other labs have suggested that butyrate signals to Campylobacter that they have reached the lower intestines of humans and should start the process of causing disease. The research for this manuscript has focused on determining the ways in which butyrate affect Campylobacter. We have discovered that butyrate reduces the ability of Campylobacter to both move through its environment and adhere to surfaces. The ability to move and adhere to surfaces are two traits that are important for Campylobacter when they are trying to start an infection in people. Additionally, we determined proteins that Campylobacter will make more or less of when exposed to butyrate. Some of the proteins that were made less when butyrate was present are necessary for Campylobacter’s ability to move while another protein LysR is believed to control the production of other proteins. We created a new Campylobacter which always makes a greater amount of the LysR protein. This new Campylobacter was able to move better in the presence of butyrate when compared to the original Campylobacter that makes less of the protein LysR. Our research suggests that the presence of butyrate should make it difficult for Campylobacter to colonize or infect the lower intestines of chickens or humans. Additionally, the protein LysR probably helps the bacteria make more of the proteins needed for movement and by getting the bacteria to make less of the protein LysR, it makes it more difficult for the bacteria to cause disease.

Technical 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 organisms 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. jejuni’s ability to infect the lower intestines. Additionally, 20mM 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 bacteria’s motility.