Mycoplasma genitalium treatment outcomes among a cohort failing macrolide resistance-guided treatment across three London sexual health clinics

Objective: British guidelines advise treatment of Mycoplasma genitalium (Mgen) infection using the results of macrolide resistance-associated mutation (MRAM) assays. Limited data informs management when patients fail MRAM-guided treatment. This study evaluates current management strategies employed for cases of Mgen infection with MRAM-guided treatment failure.

Design: This retrospective analysis reviewed laboratory and clinical data pertaining to all positive Mgen results between 28 May 2020 and 05 November 2022 across three London sexual health clinics. Treatment failure was defined as microbiological or clinical failure, despite appropriate MRAM-guided treatment with full compliance and no re-infection risk. Where MRAM status was unable to be determined, samples were excluded.

Results: 340 samples were included from mostly male (74.4%) patients with a mean age of 30 years. The majority of tests were sent for urethritis (63.8%), and most infections were present without concurrent STIs (83.5%). 183 (53.8%) samples were MRAM positive; 157 (46.1%) were wild type. 152/183 (83.1%) received MRAM-guided treatment. 49/152 (32.2%) cases of MRAM-guided treatment failure were identified. 32/49 (65.3%) achieved either microbiological or clinical cure through a variety of treatment regimens. 66.6% of nine patients who received pristinamycin achieved microbiological cure; two patients were cured by minocycline. Many patients received multiple courses of moxifloxacin despite previous failures.

Conclusion: Whilst high compliance with recommended MRAM-guided therapy was identified, there were also high rates of quinolone therapy failure (32.2%). Barriers to appropriate treatment include a lack of quinolone resistance assays and the non-availability of sitafloxacin in Europe, along with the limited availability of pristinamycin and minocycline in the UK during the study dates. We recommend developing a standardised management pathway for treatment resistant cases.