Probiotics: a role in the treatment of intestinal infection and inflammation?

Abstract

Probiotic therapy is based on the concept of normal healthy microflora. The development of novel means of characterising the gut microflora, in particular those based on the different levels of conservation in the ribosomal RNA sequences of different genera, have opened up new angles on the role of the gut microflora in health and disease. Components of the human intestinal microflora or organisms entering the intestine may have harmful or beneficial effects on human health. Abundant evidence implies that specific strains selected from the healthy gut microflora exhibit powerful antipathogenic and anti-inflammatory capabilities, and are consequently involved with enhanced colonisation resistance in the intestine. Realisation of this has led to the introduction of novel modes of therapeutic and prophylactic intervention based on the consumption of mono and mixed cultures of beneficial live microorganisms as probiotics.

Figure 1

Evolution of the gut microflora and the rationale of probiotic therapy. Different internal and external challenges interfere with the normal balance of the healthy gut microflora. Their effects can be reversed by specific strains of the healthy gut microflora. Normalisation of the properties of unbalanced indigenous microflora by specific strains of the healthy gut microflora forms the rationale of probiotic therapy.

Figure 2

Gut microflora in inflammation. Inflammation may direct the composition and function of a balanced normal microflora to become aberrant and immunogenic, leading to perpetuation of the inflammation and gut barrier dysfunction. Probiotic bacteria may counteract the inflammatory process by enhancing the degradation of enteral antigens, reducing the secretion of inflammatory mediators, and promoting the normalisation of indigenous flora and the exclusion of pathogens.