Bacterial loads of Ureaplasma urealyticum contribute to development of urethritis in men.

Ureaplasma urealyticum could be a pathogen of non-gonococcal urethritis (NGU) in men. However, ureaplasma is often detected in men without NGU, and the proportion of cases possibly attributable to this pathogen is still undefined. We attempted to determine the bacterial loads of U. urealyticum significantly associated with NGU. The 16S rRNA genes of U. urealyticum were quantified by a real-time polymerase chain reaction-based assay in first-void urine (FVU) from 26 asymptomatic and 25 symptomatic men positive for U. urealyticum. The leucocyte counts in first-void urine (FVU) were determined as an objective measure of inflammatory response to ureaplasma in the hosts by automated quantitative urine particle analysis. Positive correlations were observed between copies of the 16S rRNA genes of U. urealyticum per ml and the leucocyte counts per µl in FVU (r = 0.49, p = 0.0003). Loads of ≥10(4) copies of the 16S rRNA gene of U. urealyticum/ml, corresponding to ≥5 × 10(3) cells of U. urealyticum/ml in FVU, were significantly associated with the presence of urethritis symptoms (p < 0.0001) and with higher leukocyte counts in FVU (p < 0.0001). The bacterial load of U. urealyticum, possibly of ≥5 × 10(3) cells of U. urealyticum/ml in FVU, could be significantly associated with the development of symptomatic NGU.