Urine contamination by microorganisms may affect the interpretation of urinalysis in different areas of clinical diagnosis. This is particularly relevant in doping control. A prospective study was designed to assess the effects of urine contamination by selected pathogens on the endogenous androgenic steroid profile. Pooled urine from a healthy male volunteer with standard steroid profile compared with reference values for the Caucasian population was sterilized by filtration and stored in sterile glass tubes. Aliquots were inoculated with known amounts of 15 different organisms (bacteria, fungi, and moulds) and incubated at 37 degrees C for 2 weeks. Different markers of urine contamination, such as pH, deconjugation of steroids, and metabolic by-products, were determined. Alkalization of urinary pH was not a reliable indicator of urine contamination as several organisms grew in this medium and no alteration of this parameter was found. In uncontaminated urine, less than 10% of steroid glucuronide conjugates were spontaneously hydrolyzed. Higher rates of hydrolysis for sulfate conjugates were found. An unconjugated fraction higher than 10% of the total amount of testosterone was a reliable indicator of urine contamination. However, microbial production of testosterone or epitestosterone was not detected. In contrast, a few organisms were able to synthesize 5alpha-androstanedione, 5beta-androstanedione, and androstenedione using endogenous steroids as substrates.
Copyright 2001 Academic Press.