Non-pathogenic Escherichia coli versus mesalazine for the treatment of ulcerative colitis: a randomised trial

Background Ulcerative colitis has been suggested to be caused by infection and there is circumstantial evidence linking Escherichia coli with the cond ition. Our aim was to find out whether the administration of a non-pathogen ic strain of E coli (Nissle 1917) was as effective as mesalazine in prevent ing relapse of ulcerative colitis. We also examined whether the addition of E coli to standard medical therapy increased the chance of remission of ac tive ulcerative colitis. Methods This was a single-centre, randomised, double dummy study in which 1 20 patients with active ulcerative colitis were invited to take part. 116 p atients accepted; 59 were randomised to mesalazine and 57 to E coli. Atl pa tients also received standard medical therapy together with a 1-week course of oral gentamicin. After remission, patients were maintained on either me salazine or E coli and followed up for a maximum of 12 months. A two-stage, conditional, intention-to-treat analysis was done. Findings 44 (75%) patients in the mesalazine group attained remission compa red with 39 (68%) in the E coil group. Mean time to remission was 44 days ( median 42) in the mesalazine group and 42 days (median 37) for those treate d with E coli. In the mesalazine group, 32 (73%) patients relapsed compared with 26 (67%) in the E coli group. Mean duration of remission was 206 days in the mesalazine group (median 175) and 221 days (median 185) in the E co li group. Interpretation Our results suggest that treatment with a nonpathogenic E co li has an equivalent effect to mesalazine in maintaining remission of ulcer ative colitis. The beneficial effect of live E coli may provide clues to th e cause of ulcerative colitis.