Intestinal bypass. Bacteriological studies from different parts of the small intestine in rats

Forty-five rats were divided into four groups according to type of operation: 1) end-to-side jejunoileal bypass (ES), 10 rats; 2) end-to-end jejunoileal bypass (EE), 10 rats; 3) jejunoileal resection (R), 10 rats; and 4) no operation, 15 rats. The luminal contents from the proximal jejunum and distal ileum, in groups 1 and 2 also from the proximal and distal part of the excluded small intestine, were examined bacteriologically 5-11 months after operation. The total number of aerobic and anaerobic microbes in the jejunum was equal in all groups. The number of aerobic bacteria in the ileum was significantly higher in the ES group than in the R and U groups. The number of bacteria capable of producing gas in glucose-supplemented media was increased both in the jejunum and ileum after ES bypass. Enterobacteriaceae and Bacteroides were commonly present in the ileum after both types of bypass but were not cultured in jejunal contents. The proximal part of the excluded intestinal segment in groups 1 and 2 contained very low numbers of microbes, whereas the flora of its distal part was similar to that of the ileum in continuity in group 1. Thus, the most marked changes of the intestinal flora occurred after ES bypass in the region of the anastomosis and distal to this.