The probiotic preparation, VSL#3 induces remission in patients with mild-to-moderately active ulcerative colitis

Meta-analysis: targeting the intestinal microbiota in prophylaxis for post-operative Crohn's disease

BACKGROUND

Enteric bacteria play an important early role in the pathogenesis of Crohn's disease.

AIM

To perform a meta-analysis of trials testing antibiotics or probiotics for prevention of post-operative recurrence of Crohn's disease.

METHODS

Review of all randomized controlled trials comparing antibiotics or probiotics with placebo in prevention of endoscopic or clinical recurrence of Crohn's disease after surgical resection. Fixed-effect meta-analysis was performed with dichotomous data summarized using relative risk with 95% confidence intervals, where appropriate.

RESULTS

Seven studies were identified as suitable for inclusion (two comparing antibiotics with placebo, five comparing probiotics with placebo). The use of nitroimidazole antibiotics (metronidazole, ornidazole) reduced the risk of clinical (RR 0.23; 95% CI 0.09-0.57, NNT = 4) and endoscopic (RR 0.44; 95% CI 0.26-0.74, NNT = 4) recurrence relative to placebo. However, these agents were associated with higher risk of adverse events (RR 2.39, 95% CI 1.5-3.7) and patient withdrawal. Probiotic administration was not associated with any significant difference in risk of recurrence compared with placebo.

CONCLUSIONS

Nitroimidazole antibiotics are effective in the prevention of post-operative Crohn's disease recurrence, but their side-effects limit acceptability. Probiotics have failed to show efficacy for post-operative prophylaxis, but may merit further study.

Role of the gut microbiota in defining human health

The human superorganism is a conglomerate of mammalian and microbial cells, with the latter estimated to outnumber the former by ten to one and the microbial genetic repertoire (microbiome) to be approximately 100-times greater than that of the human host. Given the ability of the immune response to rapidly counter infectious agents, it is striking that such a large density of microbes can exist in a state of synergy within the human host. This is particularly true of the distal gastrointestinal (GI) tract, which houses up to 1000 distinct bacterial species and an estimated excess of 1 x 10(14) microorganisms. An ever-increasing body of evidence implicates the GI microbiota in defining states of health and disease. Here, we review the literature in adult and pediatric GI microbiome studies, the emerging links between microbial community structure, function, infection and disease, and the approaches to manipulate this crucial ecosystem to improve host health.

Optimizing conventional therapies for inflammatory bowel disease

Conventional therapies remain the mainstay of treatment for most patients with inflammatory bowel disease (IBD), with only a minority of patients requiring biologic therapies. Recently, attention has focused on optimizing dosing strategies for biologic agents; however, of equal importance are recent advances in the optimization of conventional IBD therapies. Newer aminosalicylate formulations demonstrate similar efficacy with a reduced pill burden and less frequent dosing, while new corticosteroid preparations may retain efficacy with a significantly improved safety profile. The limited indications for antibiotics and probiotics have been further refined by recent data, although uncertainties remain. Advances in the understanding of thiopurine metabolism continue to improve dose optimization and the potential for deliberate therapeutic manipulation with adjunctive therapies. An improved knowledge of intracellular methotrexate metabolism may translate to similar opportunities in the future. This article discusses recent advances relevant to clinical practice today.