Urinary endotoxin excretion and urinary tract infection following kidney transplantation

Following kidney transplantation, urine endotoxin levels were measured among 44 patients and compared to bacterial cultures. Urine samples were collected either via transurethral catheters or - after removal of the catheter on postoperative day 4 - by midstream void. In a control group of ten healthy volunteers, urine endotoxin levels were measured daily for 10 days. Urinary endotoxin concentration was measured by means of a chromogenically modified Limulus amebocyte lysate (LAL) test. The levels among patients with positive bacteriological findings (n = 21) were always elevated (> 0.7 EU/ml). Furthermore, there was a marked, statistically significant difference in endotoxin values between samples with bacterial growth and samples with fungal or without any growth (P < 0.001). All 21 of the 44 patients with urinary tract infection (UTI) were endotoxin-positive. Seven more patients who received antibiotics had elevated urinary endotoxin levels, but no bacterial growth in the urine culture. No bacterial infection or significant urinary endotoxin was found in the control group. In summary, the detection of urinary endotoxin in samples obtained by either suprapubic/transurethral catheters or midstream void is an early, sensitive, and specific means of diagnosis that can be carried out even during antibiotic treatment.