Abstract Body

Mycoplasma genitalium (MG) is an emerging pathogen among MSM with raising rates of antibiotic resistance. We assessed the prevalence and incidence of MG infection in MSM enrolled in the open-label phase of the ANRS IPERGAY trial with on demand TDF/FTC for HIV prevention and the impact of doxycycline post-exposure prophylaxis.

During the open-label phase of the ANRS IPERGAY trial, participants could also be enrolled in a prospective randomized (1:1) open-label sub-study of post-exposure prophylaxis (PEP) with doxycycline. All subjects were tested at baseline and at 6 months by real-time PCR assays for MG detection in urine samples, oro-pharyngeal and anal swabs. Resistance to azithromycin (AZM) and to fluoroquinolones (FQ) were investigated by the detection of mutations in 23S rRNA (ResistancePlusTM MG test, SpeeDx) and in parC determining region, respectively.

From July 2015 to January 2016, 210/232 (90.5%) participants randomized in the PEP study were tested. MG prevalence at baseline was 10.5% all sites combined (95% CI: 6.6-15.9), and was 6.3%, 4.3% and 0.5% for urine, anal and throat sites, respectively. Ten participants acquired M. genitalium infection at the 6-month visit, 6 participants in the PEP arm (6.7%) and 4 in the no PEP arm (4.9%, p= 0.75). These infections were detected in urine (n=5), anus (n=5) or throat (n=1, combined with anus). The overall rate of MG resistance (prevalent and incident cases) to AZM and FQ was 69.6% and 14.8%, respectively, with no difference between arms (p=1.00 for AZM, p=0.27 for FQ). The MG isolates were resistant by the presence of the substitutions A2058G/T or A2059G in the 23S rRNA and to FQ by the mutations S83I/B, D87Y and A88T in the QRDR of the topoisomerase ParC.

The prevalence of MG infection among MSM on PrEP with on demand TDF/FTC was high and its incidence was not decreased by doxycycline prophylaxis with a similar high rate of AZM- and FQ-resistance, raising challenging issues for the treatment of this STI.