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Original research
High prevalence of coinfection of azithromycin-resistant Mycoplasma genitalium with other STIs: a prospective observational study of London-based symptomatic and STI-contact clinic attendees
  1. Claire E Broad1,
  2. Martina Furegato1,2,
  3. Mark A Harrison1,
  4. Marcus J Pond1,
  5. NgeeKeong Tan3,
  6. Sandra Okala2,
  7. Sebastian S Fuller1,
  8. Emma M Harding-Esch1,2,
  9. S Tariq Sadiq1,2,4
  1. 1 Applied Diagnostic Research and Evaluation Unit, Institute for Infection and Immunity, St George’s University of London, London, UK
  2. 2 National Infection Service, Public Health England, Colindale, London, NW9 5EQ, UK
  3. 3 Southwest London Pathology, St George's University Hospitals NHS Foundation Trust, London, UK
  4. 4 St George's University Hospitals NHS Foundation Trust, London, UK
  1. Correspondence to Professor S Tariq Sadiq, Applied Diagnostic Research and Evaluation Unit, Institute for Infection and Immunity, St George's University of London, London SW17 0RE, UK; ssadiq{at}


Objectives Azithromycin treatment of Chlamydia trachomatis (CT) may not be adequate to treat concomitant Mycoplasma genitalium (MG) infection, and particularly if MG has macrolide resistance-associated mutations (MG-MRAMs). We estimated prevalence of coinfections of CT with MG carrying MRAM, and risk factors for MG-MRAM among a sexual health clinic population.

Study design and setting Among symptomatic and STI-contact clinic attendees in London, prevalence of CT-MG coinfection and MG-MRAM were estimated using nucleic acid amplification testing and Sanger sequencing, respectively, and their associated risk factors analysed using logistic regression.

Results MG prevalence was 7.5% (23/307), 17.3% (30/173), and 11.4% (8/70) in females, men who have sex with women (MSW) and men who have sex with men (MSM), respectively; MG coinfection in CT-infected participants represented 28.0% (7/25), 13.5% (5/37), 0.0% (0/0), respectively. Presence of MG-MRAM was 39.1% (9/23) in female swabs, 70.0% (21/30) in MSW urine and 83.3% (5/6) in MSM rectal swabs. In multivariate analyses, coinfection with another STI was strongly associated with MG-MRAM (OR: 7.19; 95% CI: 2.4 to 21.5).

Conclusion A significant proportion of participants in our study of symptomatic patients and STI contacts were infected with macrolide-resistant MG, suggesting that testing for MG and MRAM, for MG positives, might be clinically useful. The findings also suggest services explore potential benefits of testing CT positive samples for MG in these patient groups. Where MG testing is not available, potential high rates of MG coinfection should be borne in mind when considering azithromycin in the treatment of CT among STI contacts and symptomatic patients.

  • chlamydia infection
  • M. genitalium
  • azithromycin
  • antimicrobial resistance
  • gonorrhoea

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  • EMH-E and STS are joint senior authors.

  • Handling editor Joseph D Tucker

  • Contributors EMH-E and STS conceived the study, and SSF contributed to overall study concept. MAH, MJP and NKT planned and performed laboratory work. Data collection, extraction and analysis were performed by CEB, SO, MF and EMH-E. Manuscript was prepared by CEB, MF and STS.

  • Funding This work was supported by the National Institute for Health Research, Invention for Innovation (i4i) grant: 'A Point of Care Antimicrobial Resistance test for Neisseria gonorrhoeae and Mycoplasma genitalium infection - Ensuring accurate therapy and antibiotic stewardship in sexual health medicine' (II-LB-0214-20005).

  • Patient consent for publication Not required.

  • Ethics approval Ethical approval was provided by London Bridge Research Ethics Committee (reference 13/LO/0691).

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

  • Data availability statement All data relevant to the study are included in the article or uploaded as supplementary information.