Reduction of Fecal Calprotectin Levels Induced by a Short Course of Escherichia Coli Nissle is Associated with a Lower Likelihood of Disease Flares in Patients with Ulcerative Colitis in Clinical Remission

Background and aims: Fecal calprotectin (FC) is a biomarker of gut inflammation, and Escherichia coli Nissle 1917 (EcN) is a probiotic strain able to reduce gut inflammation and maintain disease remission in patients with inflammatory bowel disease (IBD). The aim is to assess the effects of EcN administration in patients with IBD in clinical remission and altered FC values. Methods: We prospectively included 82 patients with ulcerative colitis (UC) (n=49) and Crohn's disease (CD) (n=33) in clinical remission and with FC values above 250 mcg/g (T0) who were treated with EcN alone for 2 months. FC values were assessed at the end of EcN treatment (T1) and clinical disease activity at 3 months (T2). Results: At T1 median FC values were significantly lower compared to T0 both in patients with CD (312 mcg/g vs 626 mcg/g, p<0.0001) and UC (100 mcg/g vs 584 mcg/g; p<0.0001). Patients with UC who experienced disease relapse at T2 had lesser reduction in median FC values at T1 (-229 mcg/g, vs -397 mcg/g, p=0.049), while in patients with CD we observed no statistically significant difference (-358 mcg/g, vs -427; p=0.568). In patients with UC, a reduction of at least 532 mcg/g in FC had an accuracy of 69.7% and a positive predictive value of 65.7% in predicting maintenance of remission. Conclusions: A short course of EcN was associated with a reduction of FC values in patients with IBD in clinical remission and baseline altered FC values, and in patients with UC this decrease was associated with maintenance of clinical remission.