Distinguishing an infection in the upper urinary tract from one in the lower urinary tract is especially important in renal transplant patients. Although the presence of antibody-coated bacteria in the urine has been shown by others to be a reliable indication of an infection in the upper urinary tract, it was not known whether sufficient antibody to coat the bacteria would be produced in a renal transplant recipient undergoing immunosuppression. We used a fluorescent test for detecting antibody-coated bacteria in the urine to follow 80 renal transplant patients prospectively for six months. Antibody-coated bacteria were detected in specimens from four patients with a clinical picture compatible with, or histopathologic evidence of, pyelonephritis. The origin of bacteriuria in a fifth patient was indeterminate both clinically and by the fluorescent antibody test. Twenty-three other patients with bacteriuria without clinical or histopathologic evidence of pyelonephritis had negative tests for antibody-coated bacteria. One patient with pyelonephritis in her own end-stage kidney had persistent bacteriuria with a negative fluorescent antibody test. Her transplanted kidney, however, was not infected. A positive test for antibody-coated bacteria is judged useful in distinguishing an infection in the upper urinary tract from one in the lower urinary tract in the presence of immunosuppression; however, the small number of cases and the methods used do not allow us to draw a conclusion about the significance of a negative result in a population undergoing immunosuppression.
ASJC Scopus subject areas