Probiotics in the Treatment of Crohn’s Disease
Alterations in the bacterial milieu of the gut are common in Crohns disease. The use of various probiotic bacteria to promote a balance of appropriate intestinal flora has yielded mixed results. Mechanisms associated with the beneficial effects of probiotic therapy in Crohn’s Disease include:

(1) inhibition of pathogenic bacteria via growth suppression or epithelial binding
(2)  improved epithelial and mucosal barrier function; and
(3) altered immuno-regulation via stimulation of secretory IgA or reduction in TNF-alpha.

Saccharomyces boulardii
Plein et al demonstrated the efficacy of Saccharomyces boulardii (Sb) in a randomized, double-blind, placebo-controlled study of 20 Crohn’s Disease patients. Patients were given 250 mg Sb three times daily for 10 weeks and evaluated via bowel movement frequency and the CDAI index. Patients receiving Sb experienced a significant reduction in frequency of bowel movements (from 5.0 to 3.3 per day) and CDAI index (193 to 107) by week 10 of treatment.

Another study utilizing Saccharomyces boulardii therapy in 32 Crohn’s Disease patients demonstrated a significant benefit of a combination of Saccharomyces boulardii and mesalamine compared to mesalamine alone. Relapse in the mesalamine-only group was 37.5 percent at six months compared to only 6.25 percent in the mesalamine-plus Saccharomyces boulardii group.

E. coli (Nissle strain)
Pathogenic E. coli that adhere to and invade intestinal epithelial cells (IEC) have been isolated from ileal lesions of Crohns patients. Boudeau et al demonstrated the in vitro ability of a non-pathogenic E. coli strain (Nissle 1917) to prevent pathogenic E. coli strains from adhering to and invading IEC. When IEC were co-infected with probiotic Nissle strain and pathogenic E. coli, the Nissle strain exhibited a dose- and time-dependent adhesion to IEC, which prevented adhesion of various pathogenic E. coli strains by 78.0- 99.9 percent.

When IEC were pre-incubated with Nissle strain E. coli and pathogenic strains were added later, adhesion and invasion of pathogenic strains was inhibited by 97.2-99.9 percent. Malchow et al conducted a double-blind, randomized, placebo-controlled trial investigating the efficacy of E. coli Nissle strain 1917 for inducing and maintaining remission in 28 patients with colonic Crohns disease.

Patients were randomized to either 60 mg prednisolone daily (with a standard tapering schedule) plus twice daily doses of 2.5 x1010 probiotic Nissle strain E. coli (treatment group) or identical prednisolone therapy plus placebo (placebo group). The rate at which remission was achieved was comparable in both groups (85.7% for treatment patients versus 91.7% for placebo patients), but only 33.3 percent of patients in the E. coli treatment group relapsed at one year, compared to 63.6 percent in the placebo group.

Lactobacillus GG
Malin et al investigated the effect of oral Lactobacillus GG on the intestinal immunological barrier in a small study of 14 children with CD and seven control patients (hospitalized for investigation of abdominal pain but with no evidence of intestinal disease). Lactobacillus GG was administered to patients and controls at 1010 colony forming units mixed in liquid twice daily. Lactobacillus GG therapy significantly increased the IgA immune response in Crohns patients compared to controls, resulting in an improved mucosal barrier.

Another study of Lactobacillus GG demonstrated that administration in children with mildto- moderate stable Crohn’s Disease improved gut barrier function and clinical status after six months of therapy.228 However, a randomized, double-blind, placebo-controlled trial of 45 post-surgery Crohns patients given Lactobacillus GG for one year did not show it to be more effective than placebo in preventing disease recurrence.229