Introduction This study evaluated the prevalence and anatomical distribution of Mycoplasma genitalium (Mgen) 23s rRNA mutations (23s-MTs) conferring macrolide resistance among male and female subjects enrolled in a prospective multi-site US clinical study.

Methods Specimens obtained from symptomatic and asymptomatic men and women enrolled from 7 diverse US clinical sites, including obstetrics and gynaecology, family planning, public health, and sexually transmitted disease clinics, were tested using a research TMA assay for Mgen (Hologic, Inc.) on the DTS System or TIGRIS DTS System. Samples positive for Mgen by TMA were evaluated by nested PCR or RT-PCR and Sanger sequencing of Mgen 23S rRNA to identify the presence of macrolide resistance mutations at position 2058 (A2058G, A2058C, A2058T) or position 2059 (A2059G).

Results Of 50 male subjects with Mgen 23s rRNA sequence results, 21 (42%) contained 23s-MTs. Slightly more 23s-MTs were found in urethral swabs vs male urine samples (44.8% vs 36.7%, respectively). For female subjects, 65 of 128 (50.8%) harboured 23s-MTs, with higher prevalence found in vaginal swab samples (50.2%) compared to urine (46%), Thinprep liquid Pap (41.7%), and endocervical swabs (37.8%). Sequencing of samples collected from anatomically distinct female urogenital sites (vagina, cervix, urine) revealed 18 of 35 (51.4%) subjects had a unique complement of Mgen 23s-MT and/or wild-type sequences at each anatomic site. For male subjects with both urine and urethral swab samples, 3 of 9 (33.3%) subjects had unique Mgen 23s-MT/WT sequences in each sample type.

Conclusion Mgen strains harbouring 23s rRNA-mediated macrolide resistance phenotypes were highly prevalent in this US cohort of male and female subjects. Detection of different macrolide-resistant Mgen strains in samples collected from different anatomical locations suggests that previous estimates for resistance rates that relied on a single anatomical site sample collection may have underestimated the extent of Mgen macrolide resistance in the population.

Disclosure of interest statement D Getman, M O’Donnell, and A Jiang are scientists employed by Hologic. S Cohen is a student at Occidental College and a summer intern at Hologic.