Experimental foreign-body infection in the biliary tract in rats.

Background: Biomaterials used for biliary drainage may potentially result in biomaterial-associated infections. Methods: Foreign-body infection in the biliary tract was investigated in rats. Rubber drain pieces were implanted in the biliary tract in rats for 1-4 weeks, followed by challenges with 102 to 104 colony-forming units (cfu) Escherichia coli injected into the common bile duct. The rate of infection was calculated, the bacterial growth in the biliary tract was observed over 72 h after challenges, and the opsonic activity in bile and in sera was assessed. Results: In the group with drain material, inocula as small as 102 cfu produced persisting infection in the common bile duct in 90% of animals, whereas the same number of E. coli infected only 30% of rats in the control and sham implantation groups (p < 0.01, chi-square test). Complement-mediated opsonic activity in bile of animals with implanted drain pieces gradually decreased with time, whereas opsonic activity in sera from the same animals rem...