Relationship between enteric microecologic dysbiosis and bacterial translocation in acute necrotizing pancreatitis

AIM:To investigate the potential role of intestinal microflora barrier in the pathogenesis of pancreatic infection.METHODS:Fifteen dogs were colonized with a strain of E.coli JM109 bearing ampicillin resistance plasmid PUC18.The animals were divided into two groups. In experimental group (n = 8), acute necrotizing pancreatitis (ANP) was induced by injection of 0.5ml/kg of sodium tarocholate with 3000U/kg trypsin into the pancreatic duct. The control group (n = 7) underwent laparotomy only. All animals were sacrificed 7 days later. Mucosal and luminal microflora of intestine were analyzed quantitatively, and various organs were harvested for culturing, blood samples were obtained for determination of serum amylase activities and plasma lipopolysaccharide (LPS) concentrations.RESULTS:In the experimental group, the number of E. coli in the intestine was much higher than those of the controls, while bifidobacterium and lactobacillus were decreased significantly (Jejunum, 1.75 ± 0.95 vs 2.35 ± 0.79,P <0.05; 1.13 ± 0.8 vs 1.83 ± 0.64,P <0.05; ileum, 2.89 ± 0.86 vs 3.87 ± 1.05,P <0.05; 1.78 ± 0.79 vs 3.79 ± 1.11,P <0.01;cecum, 2.70 ± 0.88 vs 4.89 ± 0.87,P <001; 2.81 ± 0.73 vs 3.24 ± 0.84,P <0.05. Content of Cecum, 3.06 ± 0.87 vs 5.15 ± 1.44,P <0.01; 2.67 ± 0.61 vs 4.25 ± 0.81,P <0.01), resulting in reversal of bifido-bacterium/E. coli ratio as compared with the control group (jejunum,0.51 ± 0.76 vs 1.23 ± 0.53, P <0.05; ileum, 0.62 ± 0.68 vs 1.16 ± 0.32,P <0.05; cecum,0.46 ± 0.44 vs 1.03 ± 0.64, P < 0.05). In addition, intestinal bacteria were isolated from organs of all animals in the experimental group, and JM109 was also detected in most cases. Positive blood culture was 75.0% and 62.5% on day 1 and 2 after induction of ANP, respectively, but no bacterium was found in the controls. As compared with the control group, blood LPS levels and serum amylase activities increased 1-3 times and 3-8 times respectively.CONCLUSION: Microecological disturbance could occur in ANP, and overgrowth of intestinal gram-negative bacteria may lead to translocation to the pancreas and other organs, becoming the source of pancreatic and peripancreatic infection.