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Neisseria gonorrhoeae DNA bacterial load in men with symptomatic and asymptomatic gonococcal urethritis
  1. David Priest1,2,
  2. Jason J Ong1,2,
  3. Eric P F Chow1,2,
  4. Sepehr Tabrizi3,4,
  5. Sam Phillips3,4,
  6. Melanie Bissessor1,
  7. Christopher K Fairley1,2,
  8. Catriona S Bradshaw1,2,
  9. Tim R H Read1,2,
  10. Suzanne Garland3,4,
  11. Marcus Chen1,2
  1. 1 Melbourne Sexual Health Centre, Carlton, Victoria, Australia
  2. 2 Central Clinical School, Monash University, Clayton, Victoria, Australia
  3. 3 Department of Obstetrics and Gynaecology, University of Melbourne, Parkville, Victoria, Australia
  4. 4 Regional HPV Lab Net Reference laboratory, Department of Microbiology and Infectious Diseases, The Royal Women's Hospital, Parkville, Victoria, Australia
  1. Correspondence to Dr Jason J Ong, University of Melbourne, 580 Swanston Street, Carlton, VIC 3053, Australia; jong{at}


Objective Previous studies have quantified bacterial loads of Neisseria gonorrhoeae in the pharynx and rectum of men but not the urethra. We quantified the bacterial load of N. gonorrhoeae in men with symptomatic and asymptomatic urethral gonorrhoea infections.

Methods Consecutive men diagnosed with urethral gonorrhoea by Aptima Combo 2 testing of urine at the Melbourne Sexual Health Centre between March and July 2016 were eligible for the study: symptomatic men with purulent urethral discharge and asymptomatic men with no urethral symptoms. The gonococcal bacterial load in both groups was measured by urethral swab using a standardised collection method and real-time quantitative PCR targeting the opa gene.

Results Twenty men were recruited into the study: 16 had purulent urethral discharge and 4 had asymptomatic urethral gonorrhoea. The median gonococcal bacterial load was significantly higher among symptomatic men (3.7×106 copies per swab, IQR 2.5×106–4.7×106) compared with asymptomatic men (2.0×105 copies per swab, IQR 2.7×104–4.5×105) (p=0.002).

Conclusions Gonococcal loads in men with urethral discharge were higher than loads seen with asymptomatic urethral gonorrhoea and loads seen in asymptomatic pharyngeal and rectal gonorrhoea infections in previous studies.


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  • DP and JJO are equal first authors.

  • Handling editor Jackie A Cassell

  • Contributors The study concept was conceived by MC and designed by DP, JJO, ST and MC. DP and JJO undertook sampling and data collection. SG, ST and SP oversaw laboratory testing and analysis. All authors contributed to interpretation of the data, writing of the manuscript and approval of the final version.

  • Funding JJO, EPFC and TRHR are supported by the Australian National Health and Medical Research Council Early Career Fellowships (No. 1104781, 1091226, 1091536 respectively).

  • Competing interests None declared.

  • Ethics approval Alfred Health Human Research Ethics Committee, ethics approval number is (97/16). All patients provided written consent to join the study.

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

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