[Selective intestinal bacterial decontamination in experimental acute pancreatitis].
BACKGROUND: Bacterial translocation implies the transit of viable gastric microflora from the intestinal lumen through the intestinal wall to the mesenteric ganglia and seems to be the mechanism by which microflora reach necrotic tissue in acute pancreatitis (AP). This occurs in 40-70% of necrotizing hemorrhagic AP and plays a major role in up to 80% of deaths from this cause. AIMS: To analyze the possible influence of bacterial decontamination in the gut on bacterial translocation in severe experimental AP. METHODS: Severe AP was induced in 43 male Sprague-Dawley rats by administration of 0.2 ml of 2.5% taurodeoxycholate sodium in NaOH glycyl-glycine buffer after cannulizing the bilio-pancreatic duct through the duodenum and clamping the common bile duct in the hepatic junction. The rats were divided into two groups: a) control group: 24 rats in which only AP was induced; b) problem group: 19 rats that underwent bacterial decontamination through the administration of 4 mg/ml gentamicin, bacitracin and neomycin in the drinking water during the 5 days prior to AP induction. Twenty-four hours after AP induction, laparotomy was performed and a sample for the culture of mesenteric lymphatic ganglia, pancreas, liver, spleen, peritoneum and cecum was obtained. RESULTS: Seven rats in the control group died. Of the 17 rats that survived 24 hours, positive cultures in the pancreas were obtained in nine. In the problem group, two rats died within 24 hours. Of the remaining 17 rats, positive pancreatic cultures were obtained in 2 while in 15 pancreatic cultures were negative. No microflora were cultured in the peritoneum. The microflora most frequently cultivated were Escherichia coli, enterococcus and proteus. No differences were found in the percentage of Gram-positive and Gram-negative bacteria between the two groups. CONCLUSIONS: a) The majority of the bacteria in AP tissue originate in the intestinal microflora, E. coli being the most prevalent. b) One of the main mechanisms in this process is bacterial translocation via the lymphatic pathway; transit directly through the transperitoneal pathway is not essential. c) Bacterial translocation already occurs in the earlier phases of AP. d) Bacterial decontamination prior to AP decreases the frequency of bacterial translocation and does not interfere in the Gram-positive/Gram negative balance, nor does it increase fungal infections.