Both transcription-mediated amplification (TMA)-based MG assays had a highly superior sensitivity compared to the mgpB qPCR. The prevalence of MG and azithromycin resistance was high. Validated and quality-assured molecular tests for MG, routine resistance testing of MG-positive samples and antimicrobial resistance surveillance are crucial.

Introduction Mycoplasma genitalium (MG) is associated with urethritis in men. Treatment of urethritis with azithromycin is expected to become less effective in clients infected with MG due to an increase in macrolide resistance-associated mutations (MRAM) in MG. Therefore, we examined clinical improvement of symptoms in men receiving empirical treatment for urethritis, and correlated the clinical outcome to Neisseria gonorrhoeae (NG), Chlamydia trachomatis (CT), MG and MRAM status. Methods At the STI clinic in Amsterdam, the Netherlands, empirical treatment for gonococcal urethritis is 1g ceftriaxone and for non-gonococcal urethritis (NGU) azithromycin 1g. From May 2018 through November 2019, we tested urine samples of all men with urethritis for CT, NG and MG using TMA assays. MG-positive samples were tested for MRAM using qPCR. Men were sent a text message two weeks after receiving empirical treatment, enquiring after the clinical improvement of urethritis. Results We evaluated 2505 cases of urethritis. The positivity rate of NG, CT and MG was 26% (648/2489), 29% (726/ 2489) and 23% (522/2288) respectively. In 768/2288 (34%) of the cases no NG, CT or MG was detected. The majority of the cases (53%) were infected by one bacterial species, 18% only by NG, 486/2288 21% only by CT and 14% only by MG. Evaluation of presence of MG-MRAM could be assessed in 439/522 (84%) samples. The prevalence of MG-MRAM was 74% (327/439). In 642 (26%) cases men responded to the enquiry, of whom 515 (80%) indicated that their symptoms had improved or disappeared; 91% (159/174) in NG cases, 82% (160/195) in CT cases, 86% (24/28) in MG wild-type cases, and 60% (56/94) in MG-MRAM cases (p<0.001). Conclusions The efficacy of empirical treatment of NGU with macrolides is limited by the presence of MG-MRAM. Testing for MG-MRAM is advised in case of NGU.