Failure of local and systemic bacterial clearance in rats with acute pancreatitis

These studies were designed to investigate the ability of rats to clear subcutaneous bacterial abscesses following acute pancreatitis. Animals underwent subcutaneous injection of 1 x 10(9) Escherichia coli and Staphylococcus aureus and, 24 h later, were randomized into four groups to receive (A) an intravenous (i.v.) infusion of cerulein, (B) saline i.v., (C) ligation of the pancreatic head, or (D) sham ligation. After 12 h, abscess sizes were measured and blood was withdrawn for culture and assay amylase and endotoxin level assay. Animals were observed for an additional 12 h to record mortality. Both E. coli and S. aureus abscesses were larger in group C vs. group D, while only the E. coli lesion was larger in group A vs. group B. Bacteremia was detected in 60% of the animals in group A, 40% in groups B and D, and 100% in group C. Mortality was 80% in group C vs. 10% in all other groups. Amylase and endotoxin levels were higher in group C vs. all groups. In the second experiment rats were injected with bacteria as above. Four, twelve, and twenty-four hours later the abscesses were removed for quantitation of bacteria and histologic evaluation. At 24 h rats underwent procedure A, B, C, or D and the abscesses were excised 12 h later. Group C had a significantly higher number of viable bacteria inside the lesion compared to group D. Histology showed tissue necrosis and cellulitis not observed in group D. It is concluded that acute pancreatis causes failure of local and systemic bacterial clearance and that the incidence of bacteremia and mortality is proportional to the severity of the disease.