High rates of asymptomatic Mycoplasma genitalium infections with high proportion of genotypic resistance to first-line macrolide treatment among men enrolled in the Zurich primary HIV infection study

Abstract Background Mycoplasma genitalium (Mg) is an emerging sexually transmitted pathogen among men who have sex with men (MSM). Resistance to recommended antimicrobial agents are of public health concern. Few data exist on Mg infections in MSM diagnosed with HIV during primary HIV infection. Methods Participants of the Zurich Primary HIV Study (NCT 00537966) were systematically offered screening for sexually transmitted infections (STI) between April 2019 and September 2020. Screening was performed using an in-house PCR panel comprising Mg including genotypic resistance testing for macrolides and quinolones, Chlamydia trachomatis including serovars L1-L3, Neisseria gonorrheae, Treponema pallidum and Hemophilus ducreyi. Results We screened 148/266 (55.6%) participants with overall 415 follow-up visits. 91% were MSM. The incidence rate for all STI was 47.0 (95% CI [32.2, 68.6]) per 100 person-years. Mg was the most frequently detected pathogen: Thirty participants (20%) presented with at least one Mg infection, corresponding to a period prevalence of 20.3% and incidence rate of 19.5 Mg infections (95% CI [11.8, 32.4]). Most Mg infections (93%) were asymptomatic, and 9 (30%) participants showed spontaneous clearance. We detected high rates of antibiotic resistance: 73.3% to macrolides, 3.3% to quinolones, and 13.3% resistance to both antibiotics. Conclusion The high prevalence of mostly asymptomatic Mg infections and high rate of spontaneous clearance support cautious initiation for treatment. The high proportion of macrolide-resistant strains suggests that a genotypic determination of resistance should be standard of care. Moxifloxacin should be the preferred treatment option for symptomatic Mg infections among MSM if resistance testing is unavailable.