Probiotics in the Prevention of Urogenital Tract Infections. Mechanisms Involved

Urogenital tract infections affect a very high number of women worldwide, producing many clinical situations that imply increasing costs to the health systems, and a consequent morbility and mortality. The Urinary Tract Infections are more common in pre pubers or postmenopausal women, while the Genital Infections are more related to Sexually Active Women. Many of the applied therapeutics imply the use of antibiotics or other drugs that produce adverse effects not only in the urogenital tract, but at general level. This tract is also affected by other external or internal factors that have effect on the equilibrium of the urogenital microbiota, increasing the incidence of infections. During the last years the preventive measures are being applied around the world. In the urogenital tract, they are considerably important by the relationship with pregnancy development, newborn status and mother complications. The application of probiotics for many clinical situations, and for the restoration of the urogenital microbiota and prevention of infections, is more and more frequent. Probiotics are defined as live microorganisms administered in high numbers to the host to produce a physiological effect. The mechanisms involved in the probiotic effect include the production of antagonistic substances, the competitive exclusion phenomenon, the competition for nutrients, the colonization ability, the biofilm formation and/or the stimulation of the immune system. Some of these mechanisms have been showed by "in vitro" assays, but not yet in many "in vivo" experiments. The diversity of strains claimed as probiotics is higher every time, without the publication of clinical trails supporting their beneficial effect. These aspects and other related with the rationale of probiotic application in the urogenital tract are discussed in the present review.