Mycoplasma genitalium in Toronto, Ont

Study design

A prospective and consecutive sample of male, female, and transgender clients seeking sexual health services at the Men/Trans Clinic and Women/Trans Clinic at the Hassle Free Clinic in Toronto between September 1, 2013, and December 20, 2013 was included in the study, regardless of age. Clients could opt out of the study if they did not want to participate or if they did not want to receive M genitalium testing. Clients who opted out still received standard STI testing. Our target sample size was 1000 participants.

Biological sampling

Participants provided a first-void urine sample for STI testing. We used urine to test for M genitalium to reduce differential bias between male and female participants and to minimize clinic work. The test for M genitalium was added as a separate test in the panel. Biological samples were transported to the Public Health Ontario Laboratory with existing daily shipments for laboratory analysis.

Laboratory analysis

A sample of 1800 μL of urine was centrifuged at 20 000 g for 15 minutes, and the pellet was resuspended in 300 μL of 20% (weight/volume) ion exchange resin (Chelex 100) slurry in Tris-EDTA buffer. The mixture was vortexed for 60 seconds and incubated at 95°C for 10 minutes. After centrifugation at 20 000 g for 5 minutes, 5 μL of the supernatant was analyzed using real-time polymerase chain reaction (PCR) targeting the gene MgPa.⁹ Proficiency testing was provided by the Statens Serum Institut in Copenhagen, Denmark, to confirm the test performance within the Public Health Ontario Laboratory. Confirmation of positive samples was performed by real-time PCR using an M genitalium–specific 23S target developed at the Public Health Ontario Laboratory.⁹ Samples were considered indeterminate if they had a negative confirmatory PCR result.

All specimens with positive test results for M genitalium were analyzed for macrolide resistance–mediating mutations in region V on the 23S rRNA gene by PCR assay,¹⁰ and for mutations associated with fluoroquinolone resistance in parC and gyrA.⁶

Specimen processing occurred 2 to 5 times per week at the Public Health Ontario Laboratory, depending on sample submission volume, with the test results being communicated back to the clinic within approximately 24 hours. All participants who had positive test results for M genitalium were contacted for appropriate follow-up and treatment. Sexual contacts of those who had positive results were tested and treated as necessary.

Treatment of M genitalium

Azithromycin (500 mg on day 1, followed by 250 mg per day for 4 days) was the first-line treatment recommended for those with positive results for M genitalium. Cases identified as carriers of a strain with a macrolide resistance–mediating mutation were treated with moxifloxacin (400 mg daily for 7 days). Patients were asked to return to the clinic 2 to 4 weeks after treatment to undergo a test of cure (TOC). A repeat positive M genitalium PCR test result at the TOC was considered a treatment failure, and moxifloxacin was used to treat these infections even if no azithromycin mutations were detected.

We documented and monitored treatment outcomes to develop best-practice recommendations for uncomplicated (no co-infection, no antibiotic resistance) and complicated (co-infection or antibiotic resistance) M genitalium infection. The University of Toronto Research Ethics Board approved this study.