Susceptibility of the liver and biliary tract to anaerobic infection in extrahepatic biliary tract obstruction. Bacteriological investigations - an experimental study in rabbits.

The influence of common duct occlusion on susceptibility to infection with anaerobic gram-negative rods was investigated in rabbits. Intravenous inoculation was performed with three B. fragilis strains isolated from human infections and with a stock culture of Fusobacterium mortiferum. Liver tissue, gallbladder, bile, and blood were investigated. Anaerobic culture procedures were based on the use of a 'glove-box' with an oxygen-free atmosphere and pre-reduced, anaerobically sterilized media. Anaerobic transport was based on flushing of samples with oxygen-free carbon dioxide and transport-time less than 30 minutes. In regard to two B. fragilis strains (ss. fragilis) and in regard to Fusobacterium mortiferum, common duct occlusion significantly increased the number of infected animals compared to a control group of inoculated animals without common duct occlusion. Spontaneous infection did not arise in a control group of animals with common duct ligation. It is concluded that: 1) in biliary tract occlusion, anaerobic bacteria are able to invade the biliary tract from the blood stream, and 2) biliary tract occlusion produces sufficient anaerobic conditions for obligate anaerobic bacteria to multiply in the bile.