Significance of test for antibody-coated bacteria in biliary tract infection.

To detect a biliary tract infection, antibody-coated bacteria (ACB) in bile and duodenal juice was examined in 146 specimens from 111 patients by direct immunofluorescent antibody technique (FA test). One hundred and forty one of these specimens were also cultured and the results were compared with those of FA test. Organisms were isolated in 77 specimens from 59 patients. Thirty nine (from 31 cases) in these 77 specimens showed ACB. Result of FA test was related to clinical findings such as fever and leucocytosis, but was not to upper abdominal pain, jaundice, liver function test abnormality and the presence of gallstones. Isolates were mainly gram negative rods in ACB positive group (77%). Classification of immunoglobulin of ACB indicated a predominance of IgG and IgA classes over IgM class.