239 Evaluation of the effect of probiotic <i>E. coli</i> Nissle 1917 on <i>Campylobacter jejuni</i> infections

Objectives/Goals: Campylobacter is a foodborne pathogen, causing gastroenteritis in humans. Untreated infections can cause colorectal cancer. With rising antibiotic resistance, alternative therapies like E. coli Nissle 1917 (EcN) are urgently needed to control infections in humans. Our study aims to evaluate the effect of EcN supernatant on C. jejuni in vitro. Methods/Study Population: The efficacy of EcN CFS on the growth of C. jejuni was evaluated in LB and minimal media (M63) using agar-well diffusion assay. We also evaluated the impact of these supernatants on the biofilm formation and pre-formed biofilms, as well as on the adhesion, invasion, and survival of C. jejuni in human colorectal adenocarcinoma cells. Additionally, we examined the effects of EcN CFS on the expression of genes associated with virulence factors, biofilm production, and quorum sensing of C. jejuni using real-time polymerase chain reaction. Each of the experiments was repeated at least twice, and the results were evaluated using two-way analysis of variance. Results/Anticipated Results: Our results showed that EcN supernatants grown in both LB and M63 media exhibited a high zone of growth inhibition of Campylobacter in agar media. The EcN CFS significantly inhibited C. jejuni growth when co-cultured in liquid media. The supernatants also demonstrated a significant reduction of pre-formed biofilms by up to 82% and inhibited biofilm formation by 75%. Pretreatment of HT-29 MTX human intestinal cells with EcN supernatants led to a significant (p Discussion/Significance of Impact: Our study demonstrates that E. coli Nissle 1917 cell-free supernatant significantly inhibits C. jejuni growth and virulence. This suggests that EcN-derived bioactive compounds could be promising antibiotic alternatives to combat C. jejuni infections. This study will bridge the gap between basic and translational research.