Campylobacter jejuniresponse to ox-bile stress

Abstract

Campylobacter jejuni is a pathogen that colonizes the intestinal tract of humans and some animals. The in vitro responses of the bacterium to ox-bile were studied using proteomics to understand the molecular mechanisms employed by C. jejuni to survive bile stress. Its in vitro tolerance to bile was determined by growing the bacterium for 18 h in liquid cultures containing different bile concentrations. Significant growth inhibition was observed in the presence of 2.5% bile, and a decrease of 1.12 log units was measured at a bile concentration of 5%. Protein expression profiles of bacteria grown with and without bile were compared using two-dimensional polyacrylamide gel electrophoresis. Proteins with differential intensities greater than two-fold were identified using tandem mass spectrometry. Nuclear magnetic resonance spectroscopy and spectrophotometry were employed to measure enzyme activities in cell extracts from bacteria grown with and without bile. Together with proteins known to be involved in C. jejuni bile tolerance, the presence of bile modulated the expression of proteins such as elongation factors, ferritin, chaperones, ATP synthase and others, previously unknown to be implicated in the response of the bacterium to bile.

Culture of Campylobacter jejuni with Sodium Deoxycholate Induces Virulence Gene Expression

“…It is noteworthy that Fox et al (10) studied the effect of culturing C. jejuni with a concentration of bile that exceeds the concentration normally found in human and chicken intestinal tracts. Using a proteomic approach, these workers found that culturing C. jejuni with 2.5% ox bile for 18 h increased the synthesis of GroEL, GalU, and bacterioferritin proteins (10).…”

“…Using a proteomic approach, these workers found that culturing C. jejuni with 2.5% ox bile for 18 h increased the synthesis of GroEL, GalU, and bacterioferritin proteins (10). These proteins are indicative of a bacterial stress response.…”

Survival of the Fittest: How Bacterial Pathogens Utilize Bile To Enhance Infection

“…One study identified that flagella are necessary for enhanced C. jejuni biofilm formation following bile salts exposure, with the flagellar filament mediating attachment for the biofilm (165). Another study used proteomic two-dimensional (2D) gel electrophoresis to demonstrate that ox bile may increase the expression of flagellin A, the chemotaxis protein CheV, and the ATP synthase, suggesting that bile components may induce motility and act as chemotactic attractants for C. jejuni (166). Li et al further confirmed that bile components are chemotactic attractants after observing that methyl-accepting chemotaxis proteins are needed for chemotaxis and that the absence of these proteins, or the absence of bile, severely impairs colonization in mice (167).…”

Investigation of the effects of pH and bile on the growth of oral Campylobacter concisus strains isolated from patients with inflammatory bowel disease and controls

“…The majority of the strains of Campylobacter jejuni (60-93 %), which can cause gastroenteritis, were reported to be able to grow in the presence of 2 % ox bile . A study by Fox et al (2007) showed that when grown in culture media containing 2.5 % ox bile, the c.f.u. of C. jejuni strain NCTC 11168 decreased only 0.625 log 10 units compared to that cultured in media without bile.…”