Background: Biomaterials used for biliary drainage may potentially res
ult in biomaterial-associated infections. Methods: Foreign-body infect
ion in the biliary tract was investigated in rats. Rubber drain pieces
were implanted in the biliary tract in rats for 1-4 weeks, followed b
y challenges with 10(2) to 10(4) colony-forming units (cfu) Escherichi
a coli injected into the common bile duct. The rate of infection was c
alculated, the bacterial growth in the biliary tract was observed over
72 h after challenges, and the opsonic activity in bile and in sera w
as assessed. Results: In the group with drain material, inocula as sma
ll as 10(2) 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-s
quare test). Complement-mediated opsonic activity in bile of animals w
ith implanted drain pieces gradually decreased with time, whereas opso
nic activity in sera from the same animals remained unchanged. Conclus
ions: Implants in the biliary tract impair local host defense, resulti
ng in an increased susceptibility to microbial infection.