Why do bacteria reach ascitic fluid?

Knowledge of the pathogenesis of spontaneous bacterial peritonitis (SBP) in cirrhotic patients, in spite of the recent progress in its understanding, is still very limited. Translocation of intestinal bacteria appears to be related to bacterial overgrowth and impairment in the intestinal barrier. Later, alterations in immune defence mechanisms and in ascitic fluid antimicrobial activity play a main role in the development of SBP. Further investigation aimed at greater knowledge of the pathogenesis of SBP will hopefully lead to new strategies for its prevention and treatment. Spontaneous bacterial peritonitis (SBP) is the most common and serious infection that develops in cirrhotic patients. Translocation of bacteria from their intestinal origin, alterations in immune defence mechanisms and deficiencies in the ascitic fluid antimicrobial activity seem to represent the main steps in the pathogenesis of SBP in cirrhosis. Among the factors determining the development of bacterial translocation, intestinal bacterial overgrowth (mainly related to decreased intestinal motility) and changes in the intestinal barrier appear to play an outstanding role. In conclusion, greater understanding of the pathogenesis of SBP will allow better identification of patients at high risk of developing this complication and contribute to the search for new strategies for its prevention.