Prediction of the persistence of Mycoplasma genitalium after antimicrobial chemotherapy by quantification of leukocytes in first-void urine from patients with non-gonococcal urethritis

Mycoplasma genitalium is regarded as another pathogen of male non-gonococcal urethritis (NGU). Failure to eradicate this mycoplasma is associated with persistent or recurrent NGU, but this mycoplasma is not routinely examined in clinical practice. In cases of M. genitalium-positive NGU, therefore, some criteria are needed to assess the success or failure of antimicrobial chemotherapy other than microbiological outcomes. We enrolled 49 men with M. genitalium-positive non-chlamydial NGU. At successive visits after treatment, we inquired about their symptoms, observed their urethral meatus for urethral discharge, and examined their first-void urine (FVU) for quantification of leukocytes and for the persistence of M. genitalium. M. genitalium was eradicated in 34 patients after treatment, whereas the mycoplasma persisted in 15. Urethritis symptoms and urethral discharges were not found to be predictors of the persistence of M. genitalium up to the 25th day after the start of treatment. Leukocyte counts in FVU from the patients with persistence of M. genitalium were significantly higher than those from the patients with eradication of the mycoplasma. Leukocyte counts of 10 leukocytes/μl or more between the 18th and 24th day after the start of treatment were most significantly associated with the persistence of M. genitalium. Quantification of leukocytes in FVU would appear to be crucial to judge the outcome of treatment in patients with non-chlamydial NGU and could be helpful to predict the persistence of M. genitalium after treatment when M. genitalium is not routinely examined in clinical specimens in clinical practice.