Probiotics: overview of microbiological and immunological characteristics.

Over the last few years, probiotics (commercialized as food, dietary supplements of living bacteria or pharmaceuticals) have attracted the interest of scientists as well as consumers. Recent public interest in healthier lifestyles, together with the acceptance by physicians of nonmainstream therapies, has refocused attention on the role of human microbiota in the prevention and therapy of diseases. Modulation of the intestinal microbiota may be achieved by consuming living bacteria or by consuming a combination of probiotics and prebiotics. In addition, we are learning more about the biology of probiotic microorganisms, through sequencing their genomes, and the interactions of probiotics with human cells and with pathogenic bacteria. Results from well-conducted clinical studies help to increase the acceptance of probiotics for the treatment and prevention of selected diseases, both inside and outside the GI tract. Moreover, the use of selected probiotics for particular subject groups may provide more specific health effects. The medical profession is in an ideal position to guide the consumer towards appropriate prophylactic or therapeutic uses of probiotics in health or in specific disease states.