MANIPULATION OF THE SIZE AND CLONE OF AN INTRAABDOMINAL ABSCESS IN RATS

A rat grading model of chronic sepsis was developed by inoculation of a small (0.8 ml) or a large (1.5 ml) fecal pellet consisting of steril e rat feces, agar and a known number and strain of bacteria. A uniform spherical abscess containing Escherichia coli and Bacteroides fragili s was formed in 100% of the animals that survived the initial peritoni tis stage. The effects of a large biclonal abscess were compared with those of a small abscess and of a sham operation. The peritonitis stag e with high mortality was followed by an abscess stage. In rats with a large abscess, net body weight did not increase and there was 16% mor tality during the abscess stage. On the 7th day, severe hepatic energy deficiency and lactic acidosis occurred in the septic liver with B. f ragilis bacteremia. Rats with small abscesses showed mild metabolic di sturbances with no mortality. Standardization of rat models with chron ic graded septic abscess is possible by controlling the size of the fe cal pellet and the species and number of inoculated bacteria.