Article Text

Original article
Mycoplasma genitalium: high prevalence of resistance to macrolides and frequent anorectal infection in men who have sex with men in western Sydney
  1. Deborah L Couldwell1,2,
  2. Dean Jalocon3,
  3. Melissa Power1,
  4. Neisha J Jeoffreys3,
  5. Sharon C-A Chen2,3,
  6. David A Lewis1,2
  1. 1Western Sydney Sexual Health Centre, Parramatta, New South Wales, Australia
  2. 2Marie Bashir Institute for Infectious Diseases and Biosecurity and Sydney Medical School—Westmead, University of Sydney, Sydney, New South Wales, Australia
  3. 3Centre for Infectious Diseases and Microbiology Laboratory Services, ICPMR, NSW Health Pathology, Westmead, New South Wales, Australia
  1. Correspondence to Dr Deborah L Couldwell, Western Sydney Sexual Health Centre, Parramatta, NSW 2150, Australia; deborah.couldwell{at}


Objectives We aimed to estimate the prevalence of Mycoplasma genitalium infection and of mutations linked to macrolide resistance using the ResistancePlus MG assay (SpeeDx, Sydney, New South Wales, Australia) in first-void urine (FVU), anorectal and oropharyngeal samples from men who have sex with men (MSM) attending Western Sydney Sexual Health Centre (WSSHC).

Methods Consecutive symptomatic and asymptomatic MSM attending for STI testing were prospectively enrolled. M. genitalium testing using the ResistancePlus MG assay was performed on FVU, anorectal and oropharyngeal samples routinely collected for Chlamydia trachomatis and Neisseria gonorrhoeae assays.

Results Overall, the prevalence of M. genitalium infection in the study group was 13.4% (68/508). Most (79.4%, 54/68) M. genitalium harboured macrolide resistance mutations (87.5% of urethral and 75.6% of anorectal infections). The anorectum was the most commonly infected site (45/505, 8.9%), followed by the urethra (24/508, 4.7%). No oropharyngeal M. genitalium infections were detected (0/508). Most of the anorectal (93.3%) and urethral (79.2%) infections were asymptomatic.

MSM who were taking HIV pre-exposure prophylaxis (PrEP) were twice as likely to be infected with M. genitalium compared with MSM who were not on PrEP (OR 2.1, 95% CI 1.3 to 3.6; P=0.0041). Always using condoms for anal sex in the last 3 months was protective of infection (OR 0.8, 95% CI 0.6 to 1.0; P=0.0186).

Conclusions We demonstrated a high prevalence of M. genitalium and very high levels of macrolide resistance among MSM attending WSSHC. Our findings support the routine use of an assay to detect macrolide resistance mutations in M. genitalium infections. This will ensure, in regions or populations with high rates of macrolide resistance among M. genitalium strains, that first-line treatment with azithromycin will only be used if a macrolide-sensitive strain is identified.

  • mycoplasma genitalium
  • prevalence
  • men who have sex with men
  • anorectal
  • azithromycin
  • drug resistance

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  • Handling editor Catherine A Ison

  • Contributors All of the authors contributed to study design. MP, DLC and DAL planned and conducted the clinical aspects, and DJ, NJJ and SC planned and conducted the laboratory aspects, of the study. DJ performed most of the laboratory assays and laboratory data collection, and NJJ and SC had oversight of laboratory procedures. DLC collected clinical data, performed statistical analyses and wrote the initial manuscript draft, apart from laboratory procedures, which were written by DJ. All of the authors reviewed and made contributions to the final manuscript.

  • Funding This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors. SpeeDx (SpeeDx Pty Ltd, Sydney, NSW, Australia) is the developer and manufacturer of the assay used in this study, and supplied the ResistancePlus MG assay study test kits free of charge.

  • Competing interests SpeeDx personnel assisted with specimen extraction and provided laboratory technical advice, but were not involved in performing the ResistancePlus MG assays, or in the design, conduct or reporting of this study.

  • Ethics approval This study was approved by Western Sydney Local Health District Human Research Ethics Committee, HREC reference number: HREC/16/WMEAD/280; SSA reference number SSA/16/WMEAD/304.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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