The relative lethality of intestinal bacteria for gnotobiotic rats with experimental intestinal strangulation.

In eight experiments utilizing 28 animals each, germfree rats with and without ischemically or hemorrhagically strangulated closed loop intestinal segments were contaminated with either one of four common intestinal anaerobic bacteria, or a combination of two or three bacteria previously found to be innocuous in pure culture. The results showed that: a) in pure culture, Bacteroides fragilis, Bacteroides melaninogenicus, and Peptostreptococcus anaerobius were innocuous; b) Fusobacterium necrophorum alone was a very lethal organism that produced intense, confluent, intraperitoneal, fibrous adhesions after four to six days; and c) mixed inoculum of Klebsiella pneumoniae, Bacteroides fragilis, and/or Streptococcus faecalis was found to be lethal for gnotobiotic rats with intestinal strangulation. It is concluded that Fusobacterium necrophorum is so patent that it should be specifically treated with antibiotics when suspected or known to be present in clinical specimens. This gnotobiotic animal model will be useful to delineate the lethality of known combinations of intestinal bacteria.