Methenamine, minocycline, metronidazole and pristinamycin (M3P) for multi-drug-resistant <i>Mycoplasma genitalium</i> urethritis: A case series

Objectives Worldwide, Mycoplasma genitalium infections are becoming more resistant to both macrolides and fluoroquinolones - termed multi-drug-resistant (MDR) infections. Combination therapy has shown promise in treating other MDR pathogens. We have previously reported the first five cases of MDR M. genitalium urethritis successfully treated with a novel combination therapy regimen consisting of minocycline, metronidazole, methenamine and pristinamycin (‘M3P’). Methods We describe a second case series of four individuals treated with M3P as salvage therapy for M. genitalium urethritis. Clinical data, laboratory findings, resistance profiles, and treatment outcomes were reviewed. Results All four individuals had persistent M. genitalium urethritis and evidence of macrolide and fluoroquinolone resistance. Prior treatments included multiple courses of doxycycline, minocycline, azithromycin, fluoroquinolones, pristinamycin and other salvage regimens. Treatment with M3P for 14 days was associated with complete resolution of symptoms and negative post-treatment M. genitalium nucleic acid amplification tests in all four cases. No adverse effects were reported. Conclusions M3P is a useful salvage therapy for MDR M. genitalium infections that do not respond to other regimens.