[Bacterial translocation: gap in the shield].

The gastrointestinal tract is not only regarded as a system where nutrient absorption takes place, but also as a vital barrier against intraluminal pathogens entering the circulation and the maintenance of immune homeostasis. Bacterial translocation is defined as the penetration of viable bacteria or bacterial compounds from the gastrointestinal tract to extraintestinal sites. This disorder has been described in several clinical conditions. The main promoting factors for bacterial translocation have been proposed to be changes in the intestinal microflora, mucosal barrier failure and defects in host immunity. The presence of bacterial translocation has been associated with higher complications and mortality rates; therefore it should be taken into account in the therapeutic strategies of patients with predisposing factors.