Higher Prevalence of in Crohn's Disease Exacerbations and Strain-Dependent Increase of Epithelial Resistance.

has previously been linked to Crohn's disease (CD) exacerbations, but results are inconsistent and underlying mechanisms unknown. This study investigates the epidemiology of and its virulence factors (enterotoxin) and among 181 CD patients and the impact on the intestinal epithelial barrier . The prevalence of was significantly higher in active ( = 69/88, 78.4%) as compared to remissive ( = 58/93, 62.4%, = 0.018) CD patients. Moreover, . was associated with intestinal strictures. Interestingly, the intestinal barrier function, as examined by transepithelial electrical resistance (TEER) measurements of Caco-2 monolayers, increased when exposed to secretomes of -positive ( and isotype; increased TEER ∼160%, < 0.001) but not when exposed to negative strains. Whole metagenome sequencing and metabolomics, respectively, identified nine coding sequences and two metabolites that discriminated TEER-increasing from non-TEER-increasing strains. This study revealed a higher prevalence during exacerbation. Surprisingly, positive secretomes increased epithelial resistance, but we excluded Bft as the likely causative factor.