Bacterial translocation: impact of probiotics

Abstract

There is a considerable amount of data in humans showing that patients who cannot take in nutrients enterally have more organ failure in the intensive care unit, a less favourable prognosis, and a higher frequency of septicaemia, in particular involving bacterial species from the intestinal tract. However, there is little evidence that this is connected with translocation of bacterial species in humans. Animal data more uniformly imply the existence of such a connection. The main focus of this review is to describe different ways to alter the luminal milieu to decrease bacterial translocation. It is possible to reduce absorption of endotoxin by administration of bile salts in obstructive jaundice. Increasing the oral intake of glutamine will reduce bacterial translocation in rats with radiation-induced gut injury. The bacterial microflora plays a very important role in maintaining the normal intestinal ecological environment and supplying preferred fuels to the in testinal wall, consequently supporting the intestinal barrier. Disruption of the balance of intestinal bacterial microflora may increase the incidence of bacterial translocation by modifying intestinal barrier function. Bacterial species such as enteric Gram-negatives and Gram-positive cocci are more prone to translocation, whereas lactobacilli seem to have a protective effect. Administration of live lactobacilli either orally or by enema will reduce translocation. The mechanisms underlying the decreased translocation are not obvious. One effect may be mediated via an action on the intestinal wall and its permeability. Recently, the results of three randomized studies on the use of L. plantarum in patients with pancreatitis, undergoing liver transplantation or upper gastrointestinal surgery have been published, which all indicate a potential role for lactobacilli in translocation. In conclusion, by altering the luminal content of bacteria it seems possible to reduce the inci d ence of secondary infections. The influence of the luminal milieu on bacterial translocation is not fully understood. There is convincing evidence from experimental studies, but only circumstantial evidence from clinical studies. Keywords: Bacterial translocation; barrier function; lactobacilli; probiotics.