Objective Gonorrhoea transmission between men is currently thought to occur primarily to and from the urethra. Transmission without urethral involvement, from throat-to-throat and throat-to-anus, is considered to be uncommon. Using gonorrhoea results from male couples, we aimed to investigate the transmission dynamics of gonorrhoea. If current medical consensus is correct, then most throat and anal infections should be explained by the partner’s urethral infection.
Methods This is a cross-sectional analysis of gonorrhoea diagnosed by nucleic acid amplification tests in both partners in male couples who attended Melbourne Sexual Health Centre together between March 2015 and June 2017. Isolates obtained from culture-positive infections underwent whole genome sequencing to assess phylogenetic relatedness between partners.
Results In all 60 couples (120 men) at least one partner had gonorrhoea, and isolates had very high phylogenetic relatedness between partners. After excluding men with urethral gonorrhoea, among 32 men with anal gonorrhoea, 34% (95% CI 19% to 53 %) had a partner with throat gonorrhoea. After excluding couples where either man had urethral gonorrhoea, among 48 couples in which at least one man had throat gonorrhoea, in 23% (95% CI 12% to 37 %) of couples both men had throat gonorrhoea.
Conclusions The observed gonorrhoea positivity when urethral infection is absent supports a new paradigm of gonorrhoea transmission, where the throat is a major source of gonorrhoea transmission between men, through tongue kissing, oroanal sex and saliva use as anal lubricant. Public health messages may need to address the risk of saliva exposure during sex.
- neisseria gonorrhoea
- gay men
- transmission dynamics
- oral sex
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EPFC and CKF are joint senior authors.
Handling editor Jackie A Cassell
Presented at These data were presented as oral abstracts at the IUSTI World Congress in Dublin in June 2018 and the IUSTI Asia-Pacific Congress in Auckland in November 2018.
Contributors VJC, CKF and EPFC conceived and developed the study. CKF conceived the idea of the new paradigm of transmission for GC. VJC curated the data and conducted the analyses. BPH and DW generated the laboratory diagnostic and whole genome sequence data. DW performed bioinformatic analyses of genomic relatedness. VJC prepared the first draft with assistance from CKF and EPFC. All authors contributed to and approved of the final version.
Funding This work was supported by the Australian National Health and Medical Research Council (NHMRC) programme grant (no: 568971). EPFC is supported by the Early Career Fellowships from the NHMRC (no: 1091226). VJC is supported by a Research Training Scheme Scholarship from the Australian Government’s Department of Education and Training. DW is supported by an Early Career Fellowships from the NHMRC (APP1123854). BPH is supported by a Practitioner Fellowship (GNT1105905). VJC had full access to all data in this study and takes final responsibility for the decision to submit for publication.
Disclaimer The funding sources had no involvement in the design or analysis of this study.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval Ethics approval was obtained from the Alfred Hospital Ethics Committee, Melbourne, Australia (number 108/15). This was a retrospective analysis of de-identified data; hence, explicit consent to participate in this study was not sought from individual patients. Patients at MSHC are routinely informed that their de-identified data may be used for research purposes and that they can opt out if they object to the use of their data.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Reasonable requests for our raw data set will be considered, subject to approval from the Alfred Hospital Ethics Committee. Data from whole genome sequencing of N. gonorrhoeae samples have been uploaded onto the National Center for Biotechnology Information (NCBI), BioProject number PRJNA449254.
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