Pharmabiotic manipulation of the microbiota in gastrointestinal disorders, from rationale to reality.

The viewpoints of enthusiasts and skeptics in relation to the role of probiotics should not be allowed to distract clinicians from the bigger issue, which is the pivotal role of the microbiota in the protection against many disorders and in the pathogenesis of others. However, all probiotics, like all bacteria, are not created equal, and therapeutic deployment in a generic sense is as absurd as the administration of pills or tablets without regard for the nature of the active ingredient and the intended effect. The rationale for therapeutic manipulation or supplementation of the microbiota is sound in conditions where the intestinal ecosystem is poorly developed, such as in low birth weight neonates, or where it is profoundly disturbed, such as after broad-spectrum antibiotics. In other conditions, such as irritable bowel disorder (IBD), the efficacy of some, but not all, probiotics has been a welcome surprise. However, the impact of probiotics is likely to be modest and is probably more complicated in IBD. In choosing a probiotic strategy, clinicians should adhere to the principles of evidence-based therapeutics. These include: selection from a reputable supplier, with appropriate documentation of contents and shelf life; anticipation of strain-specific effects; avoidance of cocktails without documentation of the activities of each ingredient with absence of interstrain antagonism; and published evidence of efficacy from clinical trials.