Sepsis, the Liver and the Gut

The gastrointestinal tract has various functions including digestion, the production of hormones with local and systemic effects, a major role in immunological function, and acting as a barrier against antigens within its lumen. The intestinal microflora is an ecosystem which harbours over 400 bacterial species, predominantly anaerobes which outnumber facultative anaerobes. Most flora is present in the large bowel, mainly in the lumen and attached to the mucosa, but they do not normally penetrate the bowel wall. Intestinal bacteria form an important part of the enterohepatic circulation. Metabolites conjugated in the liver (including drugs and endogenous compounds) are excreted in bile to be deconjugated by bacterial enzymes in the intestine, so that they can then be absorbed across the intestine into the portal circulation and returned to the liver. Antibiotics that alter the intestinal flora can change the fecal excretion and the serum levels of these metabolites. Bacterial flora also increase fiber digestion and are believed to decrease the risk of gastrointestinal infections by interfering with gut pathogens. Our intestine harbours low concentrations of potentially pathogenic organisms (such as Clostridium difficile). Antibiotics that alter the normal intestinal flora can increase the risk of infection by exogenous pathogens or through the overgrowth of endogenous pathogens, like Clostridium difficile. If the bowel wall is damaged by trauma, burns or inflammation, intestinal bacteria may escape into the peritoneum to cause peritonitis and / or abscesses.[1]