Modulation of Campylobacter jejuni Motility, Adhesion to Polystyrene Surfaces, and Invasion of INT407 Cells by Quorum-Sensing Inhibition

Abstract

<i>Campylobacter jejuni</i> is a major foodborne pathogen, and the LuxS-mediated quorum-sensing (QS) system influences its motility, biofilm formation, invasion, host colonization, and virulence. QS therefore represents a target for the control of <i>C. jejuni</i>. The aim of this study was to investigate the correlation of QS inhibition with changes in <i>C. jejuni</i> motility, adhesion to polystyrene surfaces, and adhesion to and invasion of INT407 cells. This was achieved by studying (i) the <i>luxS</i>-deficient mutant and (ii) treatment of <i>C. jejuni</i> with 20 natural extracts as six essential oils, 11 ethanolic extracts, and three pure compounds. Compared to the wild-type, the Δ<i>luxS</i> mutant showed decreased motility, adhesion to polystyrene surfaces, and invasion of INT407 cells. The anti-QS effects of the treatments (<i>n</i> = 15/20) were assayed using <i>Vibrio harveyi</i> BB170 bioluminescence. Moderate positive correlation was shown between <i>C. jejuni</i> QS reduction and reduced motility (τ = 0.492, <i>p</i> = 0.024), adhesion to polystyrene surfaces (τ = 0.419, <i>p</i> = 0.008), and invasion (<i>r</i> = 0.394, <i>p</i> = 0.068). The best overall effect was achieved with a <i>Sedum rosea</i> (roseroot) extract, with 96% QS reduction, a 1.41 log (96%) decrease in adhesion to polystyrene surfaces, and an 82% decrease in invasion. We show that natural extracts can reduce motility, adhesion to polystyrene surfaces, and invasion of INT407 cells by <i>C. jejuni</i> through modulation of the LuxS (QS) system.