Development of an experimental model of induced bacterial peritonitis in cirrhotic rats with or without ascites

Spontaneous bacterial peritonitis (SBP) is a severe complication of cirrhotic patients associated with a high mortality.

To develop an available experimental model of induced bacterial peritonitis in cirrhosis.

Sprague-Dawley rats with carbon-tetrachloride-induced cirrhosis with (N=22) or without (N=101) ascites were randomized to receive an intraperitoneal administration of different concentrations of Escherichia coli (E. coli) diluted in 1 mL of sterile water in ascitic rats and in different volumes in nonascitic rats. A subgroup of nonascitic animals received ceftriaxone 4 h after E. coli inoculation. Mortality of rats was evaluated 24 h after bacterial inoculation.

None of the rats receiving sterile water alone and only one infected with 10(7) cfu of E. coli died. Ascitic rats showed a lower mortality rate than nonascitic rats infected with 10(8) or 10(9) cfu of E. coli (P<0.05). Mortality was higher with 10(9) cfu than with 10(8) cfu of E. coli in ascitic (P NS) and nonascitic (P<0.01) rats. A trend was noted to ward higher mortality in nonascitic rats inoculated with 10(8) cfu with increasing water volumes. A marked peritoneal polymorphonuclear cell response was observed 4 h after E. coli injection in both ascitic and nonascitic rats. Antibiotic therapy significantly reduced the mortality rate of rats infected with 10(8) cfu (P<0.01).

This experimental model of induced bacterial peritonitis in cirrhosis with or without ascites may represent a useful tool for the study of pathogenic events postinfection and for the design of new therapeutic strategies to treat patients with SBP.