Molecular assessment of intestinal microflora.

The application of molecular methodologies to intestinal microflora analysis should enable the development of a detailed knowledge of the microbial ecology of the human colon. This knowledge is essential to derive scientifically valid probiotics. Molecular typing (genetic fingerprinting) methods, eg, ribotyping and pulsed field gel electrophoresis of DNA digests, provide a means of distinguishing bacterial strains inhabiting the intestinal tract. Analysis of lactobacillus, bifidobacterial, and enterobacterial populations with the use of these methods has shown that human and porcine subjects harbor a characteristic collection of bacterial strains. Additionally, perturbations and transitions that occur in these populations and are caused by antibiotic administration or by autogenic or allogenic factors can be detected by molecular analysis of the intestinal microflora. In future studies, molecular typing methods could be used to analyze the composition of bacterial populations before, during, and after the administration of the probiotic product. This experimental approach would provide information on the effect of the probiotic on indigenous strains inhabiting the intestinal tract of humans and other animals.