A multicentre double-blind randomised controlled trial evaluating the efficacy of daily use of antibacterial mouthwash against oropharyngeal gonorrhoea among men who have sex with men: the OMEGA (Oral Mouthwash use to Eradicate GonorrhoeA) study protocol

Understanding Risk Factors for Oropharyngeal Gonorrhea Among Sex Workers Attending Sexual Health Clinics in 2 Australian Cities: Mixed Methods Study

BACKGROUND

The risk factors for oropharyngeal gonorrhea have not been examined in sex workers despite the increasing prevalence of gonorrhea infection.

OBJECTIVE

This study aims to determine the risk factors for oropharyngeal gonorrhea in female and gender-diverse sex workers (including cisgender and transgender women, nonbinary and gender fluid sex workers, and those with a different identity) and examine kissing, oral sex, and mouthwash practices with clients.

METHODS

This mixed methods case-control study was conducted from 2018 to 2020 at 2 sexual health clinics in Melbourne, Victoria, and Sydney, New South Wales, Australia. We recruited 83 sex workers diagnosed with oropharyngeal gonorrhea (cases) and 581 sex workers without (controls). Semistructured interviews with 19 sex workers from Melbourne were conducted.

RESULTS

In the case-control study, the median age of 664 sex workers was 30 (IQR 25-36) years. Almost 30% of sex workers (192/664, 28.9%) reported performing condomless fellatio on clients. Performing condomless fellatio with clients was the only behavior associated with oropharyngeal gonorrhea (adjusted odds ratio 3.6, 95% CI 1.7-7.6; P=.001). Most participants (521/664, 78.5%) used mouthwash frequently. In the qualitative study, almost all sex workers reported kissing clients due to demand and generally reported following clients' lead with regard to kissing style and duration. However, they used condoms for fellatio because they considered it a risky practice for contracting sexually transmitted infections, unlike cunnilingus without a dental dam.

CONCLUSIONS

Our study shows that condomless fellatio is a risk factor for oropharyngeal gonorrhea among sex workers despite most sex workers using condoms with their clients for fellatio. Novel interventions, particularly targeting the oropharynx, will be required for oropharyngeal gonorrhea prevention.

Gonorrhea caused due to antimicrobial-resistant bacteria Neisseria gonorrhoeae treated using probiotic peptide

Neisseria gonorrhea is a sexually transmitted disease from gonorrhea that lacks treatment; despite the urgency, the absence of adequate drugs, lack of human correlates of protection, and inadequate animal models of infection have delayed progress toward the prevention of gonococcal infection. Lactobacillus crispatus is a lactic acid bacterium typically found in the human vaginal microbiota. Peptides from L. crispatus have shown a potential therapeutic option for targetting N. gonorrhea. Bioinformatics analysis is important for speeding up drug target acquisition, screening refinement, and evaluating adverse effects and drug resistance prediction. Therefore, this study identified an antimicrobial peptide from the bacteriocin immunity protein (BIP) of L. crispatus using the bioinformatics tool and Collection of Antimicrobial Peptide (CAMPR3). Based on the AMP score and highest ADMET properties, the peptide SM20 was chosen for docking analysis. SM20 was docked against multiple proteins from the genome of the AMR bacterium N. gonorrhea using an online tool; protein-peptide interactions were established and visualized using the PyMol visualizing tool. Molecular docking was carried out using the CABSdock tool, and multiple conformations were obtained against the membrane proteins of N. gonorrhoea. The peptide SM20 exhibited higher docking scores and ADMET properties. Therefore, SM20 could be further encapsulated with cellulose; it can be applied topically to the genital tract to target N. gonorrhea infection. The controlled release of the antimicrobial peptide from the gel can provide sustained delivery of the treatment, increasing its efficacy and reducing the risk of resistance development.

Management of Neisseria gonorrhoeae in the United States: Summary of Evidence From the Development of the 2020 Gonorrhea Treatment Recommendations and the 2021 Centers for Disease Control and Prevention Sexually Transmitted Infection Treatment Guidelines

INTRODUCTION

Neisseria gonorrhoeae has developed resistance to all first-line recommended therapies, making gonococcal antimicrobial resistance a major public health concern given limited antibiotic options currently and an even smaller antimicrobial development pipeline. Since the release of the Centers for Disease Control and Prevention (CDC) 2015 STD Treatment Guidelines, azithromycin, part of the 2015 dual-drug treatment regimen, has had a rapid rise in resistance. The 2020 CDC Gonorrhea Treatment Recommendations and the 2021 Sexually Transmitted Infections (STI) Treatment Guidelines were developed weighing the priorities of treating the individual, protecting the population, and preventing antimicrobial resistance.

METHODS

Gonorrhea subject matter experts (SME) generated 8 key questions and conducted a literature review of updated data from 2013 to 2019 on gonorrhea antimicrobial resistance, treatment failures, clinical trials, and other key topics. More than 2200 abstracts were assessed, and 248 clinically relevant articles were thoroughly reviewed. SMEs also evaluated N gonorrhoeae antimicrobial resistance data from the Gonococcal Isolate Surveillance Project (GISP).

EVIDENCE

Although there have been reports of ceftriaxone treatment failures internationally, GISP data suggest that ceftriaxone minimal inhibitory concentrations (MICs) have remained stable in the United States, with < 0.1% exhibiting an "alert value" MIC (> 0.25 mcg/mL). However, GISP documented a rapid rise in the proportion of isolates with an elevated MIC (≥ 2.0 mcg/mL) to azithromycin-nearly 5% in 2018. At the same time, new pharmacokinetic/pharmacodynamic data are available, and there is greater recognition of the need for antimicrobial stewardship.

SUMMARY

The 2021 CDC STI Treatment Guidelines now recommend 500mg ceftriaxone intramuscularly once for the treatment of uncomplicated gonorrhea at all anatomic sites. If coinfection with chlamydia has not been excluded, cotreatment with doxycycline 100mg twice daily for 7 days should be added. Few alternative therapies exist for persons with cephalosporin allergies; there are no recommended alternative therapies for N gonorrhoeae infection of the throat.

The Potential Impact of a Gel-Based Point-of-Sex Intervention in Reducing Gonorrhea Incidence Among Gay and Bisexual Men: A Modeling Study

BACKGROUND

Increases in sexually transmitted infections among gay and bisexual men (GBM) over the past decade have coincided with declines in condom use and rapid uptake of HIV preexposure prophylaxis (PrEP). We explored the impact of an antimicrobial gel-based point-of-sex intervention (gel-PSI) with a lower efficacy for reducing gonorrhea transmission risk than condoms on population-level gonorrhea incidence among GBM in Victoria, Australia.

METHODS

A deterministic compartmental model of HIV and gonorrhea transmission was used to project annual gonorrhea incidence from 2020 to 2025. Individuals were classified as HIV-negative (PrEP or non-PrEP users) or HIV-positive, and further stratified by gonorrhoea risk (high/low). All possible scenarios where between 0% and 100% of GBM using condoms transitioned to gel-PSI (considered a downgrade in protection) and 0% and 100% of GBM not using condoms transitioned to gel-PSI (considered an upgrade in protection), with gel-PSI efficacy ranging from 20% to 50%, were run.

RESULTS

The baseline scenario of no gel-PSI uptake (status quo) projected 94,367 gonorrhea infections between 2020 and 2025, with an exponentially increasing trend in annual infections. For a gel-PSI efficacy of 30%, a net reduction in cumulative gonorrhea incidence was projected, relative to the status quo, for any ratio of proportion of condom users "downgrading" to proportion of noncondom users "upgrading" to gel-PSI use of less than 2.6. Under the supposition of equal proportions of condom users and noncondom users switching to gel-PSI, a relative reduction was projected for any gel-PSI efficacy greater than 16%.

CONCLUSIONS

Our model suggests that the introduction of a gel-PSI could have benefits for controlling gonorrhea transmission among GBM, even in scenarios where the gel-PSI is considerably less efficacious than condoms and when gel-PSI uptake leads to consequent reductions in consistent condom use.

Facing increased sexually transmitted infection incidence in HIV preexposure prophylaxis cohorts: what are the underlying determinants and what can be done?

PURPOSE OF REVIEW

The combined incidence of chlamydia, gonorrhoea and syphilis in MSM PrEP (preexposure prophylaxis) cohorts now frequently exceeds 100 per 100 person years. The efficacy of antiretroviral PrEP in reducing HIV transmission has led to efforts to find similar biomedical ways reduce sexually transmitted infection (STI) incidence. We review the recent evidence for these and other strategies.

RECENT FINDINGS

Doxycycline PrEP/postexposure prophylaxis has been shown to reduce the incidence of syphilis and chlamydia but not gonorrhoea. A meningococcal vaccine has been found to result in a lower incidence of gonorrhoea. Novel insights into the role of the pharynx in the transmission of gonorrhoea have led to clinical trials of oral antiseptics to reduce the spread of gonorrhoea. Intensified STI screening has been introduced in a number of clinics. Serious concerns have however been raised about the emergence of resistance to each of these strategies. This is particularly true for doxycycline PrEP which is not advocated by any guidelines we reviewed.

SUMMARY

Randomized controlled trials are urgently required to ascertain the benefits and risks of interventions to reduce STIs in MSM PrEP cohorts.

Antiseptic mouthwash for gonorrhoea prevention (OMEGA): a randomised, double-blind, parallel-group, multicentre trial

BACKGROUND

To address the increasing incidence of gonorrhoea and antimicrobial resistance, we compared the efficacy of Listerine and Biotène mouthwashes for preventing gonorrhoea among men who have sex with men (MSM).

METHODS

The OMEGA trial was a multicentre, parallel-group, double-blind randomised controlled trial among MSM, done at three urban sexual health clinics and one general practice clinic in Australia. Men were eligible if they were diagnosed with oropharyngeal gonorrhoea by nucleic acid amplification test (NAAT) in the previous 30 days or were aged 16-24 years. They were randomly assigned to receive Listerine (intervention) or Biotène (control) via a computer-generated sequence (1:1 ratio, block size of four). Participants, clinicians, data collectors, data analysts, and outcome adjudicators were masked to the interventions after assignment. Participants were instructed to rinse and gargle with 20 mL of mouthwash for 60 s at least once daily for 12 weeks. Oropharyngeal swabs were collected by research nurses every 6 weeks, and participants provided saliva samples every 3 weeks, to be tested for Neisseria gonorrhoeae with NAAT and quantitative PCR. The primary outcome was proportion of MSM diagnosed with oropharyngeal N gonorrhoeae infection at any point over the 12-week period, defined as a positive result for either oropharyngeal swabs or saliva samples by NAAT, and the cumulative incidence of oropharyngeal gonorrhoea at the week 12 visit. A modified intention-to-treat analysis for the primary outcome was done that included men who provided at least one follow-up specimen over the 12-week study period. The trial was registered on the Australian and New Zealand Clinical Trials Registry (ACTRN12616000247471).

FINDINGS

Between March 30, 2016, and Oct 26, 2018, 786 MSM were screened and 256 were excluded. 264 MSM were randomly assigned to the Biotène group and 266 to the Listerine group. The analysis population included 227 (86%) men in the Biotène group and 219 (82%) in the Listerine group. Oropharyngeal gonorrhoea was detected in ten (4%) of 227 of MSM in the Biotène group and in 15 (7%) of 219 in the Listerine group (adjusted risk difference 2·5%, 95% CI -1·8 to 6·8). The cumulative incidence of oropharyngeal gonorrhoea at the week 12 visit did not differ between the two mouthwash groups (adjusted risk difference 3·1%, 95% CI -1·4 to 7·7).

INTERPRETATION

Listerine did not reduce the incidence of oropharyngeal gonorrhoea compared with Biotène. However, previous research suggests that mouthwash might reduce the infectivity of oropharyngeal gonorrhoea; therefore, further studies of mouthwash examining its inhibitory effect on N gonorrhoeae are warranted to determine if it has a potential role for the prevention of transmission.

FUNDING

Australian National Health and Medical Research Council.

Antibacterial mouthwash to prevent sexually transmitted infections in men who have sex with men taking HIV pre-exposure prophylaxis (PReGo): a randomised, placebo-controlled, crossover trial

BACKGROUND

Bacterial sexually transmitted infections (STIs) are highly prevalent among men who have sex with men who use HIV pre-exposure prophylaxis (PrEP), which leads to antimicrobial consumption linked to the emergence of antimicrobial resistance. We aimed to assess use of an antiseptic mouthwash as an antibiotic sparing approach to prevent STIs.

METHODS

We invited people using PrEP who had an STI in the past 24 months to participate in this single-centre, randomised, double-blind, placebo-controlled, AB/BA crossover superiority trial at the Institute of Tropical Medicine in Antwerp, Belgium. Using block randomisation (block size eight), participants were assigned (1:1) to first receive Listerine Cool Mint or a placebo mouthwash. They were required to use the study mouthwashes daily and before and after sex for 3 months each and to ask their sexual partners to use the mouthwash before and after sex. Participants were screened every 3 months for syphilis, chlamydia, and gonorrhoea at the oropharynx, anorectum, and urethra. The primary outcome was combined incidence of these STIs during each 3-month period, assessed in the intention-to-treat population, which included all participants who completed at least the first 3-month period. Safety was assessed as a secondary outcome. This trial is registered with Clinicaltrials.gov, NCT03881007.

FINDINGS

Between April 2, 2019, and March 13, 2020, 343 participants were enrolled: 172 in the Listerine followed by placebo (Listerine-placebo) group and 171 in the placebo followed by Listerine (placebo-Listerine) group. The trial was terminated prematurely because of the COVID-19 pandemic. 151 participants completed the entire study, and 89 completed only the first 3-month period. 31 participants withdrew consent, ten were lost to follow-up, and one acquired HIV. In the Listerine-placebo group, the STI incidence rate was 140·4 per 100 person-years during the Listerine period, and 102·6 per 100 person-years during the placebo period. In the placebo-Listerine arm, the STI incidence rate was 133·9 per 100 person-years during the placebo period, and 147·5 per 100 person-years during the Listerine period. We did not find that Listerine significantly reduced STI incidence (IRR 1·17, 95% CI 0·84-1·64). Numbers of adverse events were not significantly higher than at baseline and were similar while using Listerine and placebo. Four serious adverse events (one HIV-infection, one severe depression, one Ludwig's angina, and one testicular carcinoma) were not considered to be related to use of mouthwash.

INTERPRETATION

Our findings do not support the use of Listerine Cool Mint as a way to prevent STI acquisition among high-risk populations.

FUNDING

Belgian Research Foundation - Flanders (FWO 121·00).

Anti-Virulence Therapeutic Approaches for Neisseria gonorrhoeae

While antimicrobial resistance (AMR) is seen in both Neisseria gonorrhoeae and Neisseria meningitidis, the former has become resistant to commonly available over-the-counter antibiotic treatments. It is imperative then to develop new therapies that combat current AMR isolates whilst also circumventing the pathways leading to the development of AMR. This review highlights the growing research interest in developing anti-virulence therapies (AVTs) which are directed towards inhibiting virulence factors to prevent infection. By targeting virulence factors that are not essential for gonococcal survival, it is hypothesized that this will impart a smaller selective pressure for the emergence of resistance in the pathogen and in the microbiome, thus avoiding AMR development to the anti-infective. This review summates the current basis of numerous anti-virulence strategies being explored for N. gonorrhoeae.

Associations between oral sex practices and frequent mouthwash use in heterosexuals: a cross-sectional survey in Melbourne, Australia

OBJECTIVE

This study aimed to determine the frequency of mouthwash use and its association to oral sex practice in heterosexuals.

DESIGN

A cross-sectional study.

SETTING

Data obtained from a sexual health clinic in Victoria, Australia, between March 2019 and April 2019.

PARTICIPANTS

Heterosexual men and women attending the sexual health clinic answered a survey using computer-assisted self-interview.

PRIMARY AND SECONDARY OUTCOME MEASURES

Univariable and multivariable logistic regression were performed to examine the association between frequent mouthwash use (ie, daily or weekly mouthwash use) and oral sex practices (including tongue kissing, fellatio, cunnilingus and insertive rimming).

RESULTS

There were 681 heterosexuals included in the analysis: 315 (46.3%) men and 366 (53.7%) women. Of participants, 302 (44.3%) used mouthwash frequently, 173 (25.4%) used mouthwash infrequently and 206 (30.2%) never used mouthwash. There was no significant difference in the proportion of frequent mouthwash users between men and women (46.4% of men vs 42.6% of women; p=0.329). The proportion of frequent mouthwash users increased with increasing age groups (39.3% in ≤24 years, 45.2% in 25-34 years and 52.8% in ≥35 years or older; p_trend=0.039) with those aged ≥35 years having a 1.80 times (95% CI: 1.12 to 2.89) higher odds of being a frequent mouthwash user than those aged ≤24 years. There were no significant associations between frequent mouthwash users had sexually transmitted infection (STI) risk after adjusting for age and country of birth.

CONCLUSION

Older heterosexuals are more likely to use mouthwash. Given the high proportion and associations of mouthwash use in heterosexuals, future investigations related to oral STIs in this group should include mouthwash use.

Background review for the '2020 European guideline for the diagnosis and treatment of gonorrhoea in adults'

Gonorrhoea is a major public health concern globally. Increasing incidence and sporadic ceftriaxone-resistant cases, including treatment failures, are growing concerns. The 2020 European gonorrhoea guideline provides up-to-date evidence-based guidance regarding the diagnosis and treatment of gonorrhoea. The updates and recommendations emphasize significantly increasing gonorrhoea incidence; broad indications for increased testing with validated and quality-assured nucleic acid amplification tests (NAATs) and culture; dual antimicrobial therapy including high-dose ceftriaxone and azithromycin (ceftriaxone 1 g plus azithromycin 2 g) OR ceftriaxone 1 g monotherapy (ONLY in well-controlled settings, see guideline for details) for uncomplicated gonorrhoea when the antimicrobial susceptibility is unknown; recommendation of test of cure (TOC) in all gonorrhoea cases to ensure eradication of infection and identify resistance; and enhanced surveillance of treatment failures when recommended treatment regimens have been used. Improvements in access to appropriate testing, test performance, diagnostics, antimicrobial susceptibility surveillance and treatment, and follow-up of gonorrhoea patients are essential in controlling gonorrhoea and to mitigate the emergence and/or spread of ceftriaxone resistance and multidrug-resistant and extensively drug-resistant gonorrhoea. This review provides the detailed background, evidence base and discussions, for the 2020 European guideline for the diagnosis and treatment of gonorrhoea in adults (Unemo M, et al. Int J STD AIDS. 2020).

Incidence and duration of incident oropharyngeal gonorrhoea and chlamydia infections among men who have sex with men: prospective cohort study

Objectives

This prospective cohort study aimed to determine the natural history and incidence of oropharyngeal gonorrhoea and chlamydia among a cohort of men who have sex with men (MSM) over a 12-week period, and to examine risk factors associated with incident oropharyngeal infections.

Methods

MSM either aged ≥18 years and had a diagnosis of oropharyngeal gonorrhoea by nucleic acid amplification test (NAAT) in the past 3 months or aged 18–35 years who were HIV-negative taking pre-exposure prophylaxis (PrEP) were eligible for this study. Enrolled men were followed up for 12 weeks. Oropharyngeal swabs were collected at week 0 (baseline) and week 12 (end of study). Between these time points, weekly saliva specimens and the number of tongue kissing, penile–oral and insertive rimming partners were collected by post. Oropharyngeal swabs and saliva specimens were tested by NAAT for Neisseria gonorrhoeae and Chlamydia trachomatis. Poisson regression was performed to examine the risk factors (weekly number of partners) associated with incident oropharyngeal gonorrhoea.

Results

A total of 100 MSM were recruited. The incidence of oropharyngeal gonorrhoea and chlamydia was 62 (95% CI 37 to 105) and 9 (95% CI 2 to 35)/100 person-years, respectively. The median duration of incident oropharyngeal infection with gonorrhoea was 28 days (IQR=21–36, n=7). The incidence rate ratio (IRR) for oropharyngeal gonorrhoea increased with an increased number of kissing partners (IRR=1.08; 95% CI 1.03 to 1.12) an increased number of penile-oral sex partners (IRR=1.07, 95% CI 1.01 to 1.14) but not with an increased number of insertive rimming partners (IRR=1.11, 95% CI 0.96 to 1.29) or other demographic factors. The IRR and duration of incident oropharyngeal chlamydia were not calculated due to the small number of cases (n=2).

Conclusions

MSM have a high incidence of oropharyngeal gonorrhoea and the median duration of infection was less than 3 months.

An open-label, parallel-group, randomised controlled trial of antiseptic mouthwash versus antibiotics for oropharyngeal gonorrhoea treatment (OMEGA2)

New treatments for oropharyngeal gonorrhoea are required to address rising antimicrobial resistance. We aimed to examine the efficacy of a 14-day course of mouthwash twice daily compared to standard treatment (antibiotic) for the treatment of oropharyngeal gonorrhoea. The OMEGA2 trial was a parallel-group and open-labelled randomised controlled trial among men with untreated oropharyngeal gonorrhoea that was conducted between September 2018 and February 2020 at Melbourne Sexual Health Centre in Australia. Men were randomised to the intervention (rinsing, gargling and spraying mouthwash twice daily for 14 days) or control (standard treatment) arm and followed for 28 days. Participants in both arms were advised to abstain from sex and kissing with anyone for 14 days after enrolment. Oropharyngeal swabs were collected at baseline, Day 14 and Day 28 and tested for Neisseria gonorrhoeae by nucleic acid amplification test (NAAT) and culture. The primary outcome was the detection of oropharyngeal N. gonorrhoeae by NAAT at Day 14 after treatment. This trial was registered on the Australian and New Zealand Clinical Trials Registry (ACTRN12618001380280). This trial stopped early due to a high failure rate in the mouthwash arm. Twelve men were randomly assigned to either mouthwash (n = 6) or standard treatment (n = 6). Of the 11 men who returned at Day 14, the cure rate for oropharyngeal gonorrhoea in the mouthwash arm was 20% (95% CI 1-72%; 1/5) and in the standard treatment arm was 100% (95% CI 54-100%; 6/6). A 14-day course of mouthwash failed to cure a high proportion of oropharyngeal gonorrhoea cases.

Duration of gargling and rinsing among frequent mouthwash users: a cross-sectional study

OBJECTIVE

To examine the rinsing and gargling mouthwash practices among frequent mouthwash users to determine if there are differences in use between gender, sexual orientation and sex work status.

DESIGN

Cross-sectional study.

SETTING

Data obtained from patients attending a sexual health centre located in Melbourne, Australia.

PARTICIPANTS

200 frequent mouthwash users (four or more times per week), 50 for each of the following patient groups: men who have sex with men (MSM), female sex workers (FSW), females who are not sex workers and men who have sex with women only (MSW). Participants were observed and audio recorded using mouthwash.

PRIMARY AND SECONDARY OUTCOME MEASURES

Descriptive analyses were conducted to calculate the median age, time rinsing and gargling, amount of mouthwash used and proportion of participants who rinsed, gargled or both, as determined from the audio files. Kruskal-Wallis H test and χ² test were used to examine differences between the patient groups.

RESULTS

Median age was 28 years (IQR: 24-33). During the study, most (n=127; 63.5%) rinsed and gargled, but 70 (35.0%) rinsed only and three (1.5%) gargled only. Median time rinsing was 13.5 s (IQR: 8.5-22.0 s), gargling was 4.0 s (IQR: 2.5-6.0 s) and the median total duration was 17.0 s (IQR: 11.5-25.8 s). Median duration of mouthwash did not differ significantly between the groups (females not sex workers: 18.8 s (IQR: 12.5-24.5 s); FSW: 14.0 s (9.0-22.0 s); MSM: 22.3 s (13.0-26.5 s); MSW: 15.8 s (12.0-25.0 s); p=0.070) but males used mouthwash longer than females (median 20.3 s compared with 15.5 s; p=0.034). The median volume of mouthwash used was 20 mL (IQR: 15-27 mL). And most (n=198; 99.0%) did not dilute mouthwash with water.

CONCLUSION

Over a quarter of frequent users do not gargle mouthwash at all (35%) and used it for a substantially shorter period of time than it was used in the randomised trial (1 min) where it was shown to be effective at inhibiting Neisseria gonorrhoeae growth. Our findings suggest that many frequent mouthwash users do not follow the manufacturer instructions for using mouthwash and may not use mouthwash in a way that was shown to reduce the growth of oropharyngeal gonorrhoea.

Gonorrhoea gone wild: rising incidence of gonorrhoea and associated risk factors among gay and bisexual men attending Australian sexual health clinics

Background Gonorrhoea notifications continue to rise among gay and bisexual men in Australia and around the world. More information is needed on infection trends, accounting for testing and complimented by demographics and risk practices.

METHODS

A retrospective cohort analysis was undertaken using repeat gonorrhoea testing data among gay and bisexual men from 2010 to 2017, which was extracted from a network of 47 sexual health clinics across Australia. Poisson and Cox regression analyses were used to determine temporal trends in gonorrhoea incidence rates, as well as associated demographic and behavioural factors.

RESULTS

The present analysis included 46904 gay and bisexual men. Gonorrhoea incidence at any anatomical site increased from 14.1/100 person years (PY) in 2010 to 24.6/100 PY in 2017 (P<0.001), with the greatest increase in infections of the pharynx (5.6-15.9/100 PY, P<0.001) and rectum (6.6-14.8/100 PY, P<0.001). After adjusting for symptomatic and contact-driven presentations, the strongest predictors of infection were having more than 20 sexual partners in a year (hazard ratio (HR)=1.9, 95% confidence interval (CI): 1.7-2.2), using injecting drugs (HR=1.7, 95%CI: 1.4-2.0), being HIV positive (HR=1.4, 95%CI: 1.2-1.6) and being aged less than 30 years old (HR=1.4, 95%CI: 1.2-1.6).

CONCLUSIONS

Gonorrhoea has increased dramatically among gay and bisexual men in Australia. Enhanced prevention efforts, as well as more detailed, network-driven research are required to combat gonorrhoea among young men, those with HIV and those who use injecting drugs.

Associations between oral sex practices and frequent mouthwash use in men who have sex with men: implications for gonorrhoea prevention

Background Rates of gonorrhoea continue to rise among men who have sex with men (MSM) in Australia and worldwide. Recently, it has been proposed that oropharyngeal gonorrhoea may play a role in its onward transmission and that mouthwash use may be an effective intervention for gonorrhoea prevention and control. The objective of this study was to determine the association between specific oral sex practices and frequency of mouthwash use.

METHODS

A questionnaire-based study was conducted among MSM attending the Melbourne Sexual Health Centre in Australia from March to September 2015. Logistic regression was performed to examine the association between frequent mouthwash use (i.e. daily or weekly mouthwash use) and four oral sex practices (tongue kissing, receptive fellatio with or without ejaculation, and insertive rimming) among MSM.

RESULTS

Of the 918 MSM included in the final analysis, 490 men (53.4%) were frequent mouthwash users. Participants aged 24-34 years were 2.13-fold (95% CI 1.52-2.98) and those ≥35 years were 2.64-fold (95% CI 1.83-3.83) more likely to use mouthwash frequently than those aged ≤24 years. The most common oral sex practice was tongue kissing (n=874; 95.2%), followed by receptive fellatio without ejaculation (n=839; 91.4%), receptive fellatio with ejaculation (n=610; 66.5%), then insertive rimming (n=356; 38.8%). No significant association was found between frequent mouthwash use and tongue kissing, receptive fellatio with or without ejaculation, or insertive rimming with regular or casual male partners in the previous 3 months.

CONCLUSIONS

Younger MSM are less likely to use mouthwash. There is no association between engaging in oral sex practices and frequent mouthwash use among MSM.

Gonorrhoea: tackling the global epidemic in the era of rising antimicrobial resistance

This Special Issue of Sexual Health aims to collate the latest evidence base focussed on understanding the current epidemic and transmission of gonorrhoea, choice of treatment, molecular epidemiology application, concerns about antimicrobial resistance and alternative prevention and control for gonorrhoea.

Translating mouthwash use for gonorrhoea prevention into a public health campaign: identifying current knowledge and research gaps

The gonorrhoea rate among gay and bisexual men who have sex with men (MSM) has been increasing rapidly in many Western countries. Furthermore, gonorrhoea is becoming increasingly resistant to antibiotics and only limited options remain for treatment. Recent evidence suggests that the oropharynx may play an important role in gonorrhoea transmission. It is hypothesised that reducing the prevalence of oropharyngeal gonorrhoea will also reduce the population incidence of gonorrhoea. Mouthwash has been proposed as a novel non-antibiotic intervention to prevent oropharyngeal gonorrhoea; hence, reducing the probability of antibiotic resistance developing. However, its efficacy is yet to be confirmed by a randomised controlled trial - the findings of which will be available in 2019. If the trial shows mouthwash is effective in preventing gonorrhoea, this finding could potentially be translated into a public health campaign to increase the mouthwash use in the MSM population. This article summarises the current evidence of the effectiveness of mouthwash against gonorrhoea and discusses the potential literature gaps before implementing the mouthwash intervention at a population level.

Gonococcal vaccines: Public health value and preferred product characteristics; report of a WHO global stakeholder consultation, January 2019

Renewed interest in developing vaccines against Neisseria gonorrhoeae has been sparked by the increasing threat of gonococcal antimicrobial resistance (AMR) and growing optimism that gonococcal vaccines are biologically feasible. Evidence suggests serogroup B Neisseria meningitidis vaccines might provide some cross-protection against N. gonorrhoeae, and new gonococcal vaccine candidates based on several approaches are currently in preclinical development. To further stimulate investment and accelerate development of gonococcal vaccines, greater understanding is needed regarding the overall value that gonococcal vaccines might have in addressing public health and societal goals in low-, middle-, and high-income country contexts and how future gonococcal vaccines might be accepted and used, if available. In January 2019, the World Health Organization (WHO) convened a multidisciplinary international group of experts to lay the groundwork for understanding the potential health, economic, and societal value of gonococcal vaccines and their likely acceptance and use, and for developing gonococcal vaccine preferred product characteristics (PPCs). WHO PPCs describe preferences for vaccine attributes that would help optimize vaccine value and use in meeting the global public health need. This paper describes the main discussion points and conclusions from the January 2019 meeting of experts. Participants emphasized the need for vaccines to control N. gonorrhoeae infections with the ultimate goals of preventing adverse sexual and reproductive health outcomes (e.g., infertility) and reducing the impact of gonococcal AMR. Meeting participants also discussed important PPC considerations (e.g., vaccine indications, target populations, and potential immunization strategies) and highlighted crucial research and data needs for guiding the value assessment and PPCs for gonococcal vaccines and advancing gonococcal vaccine development.

The frontiers of addressing antibiotic resistance in Neisseria gonorrhoeae

The sexually transmitted infection gonorrhea, caused by the Gram-negative bacterium Neisseria gonorrhoeae, can cause urethritis, cervicitis, and systemic disease, among other manifestations. N. gonorrhoeae has rapidly rising incidence along with increasing levels of antibiotic resistance to a broad range of drugs including first-line treatments. The rise in resistance has led to fears of untreatable gonorrhea causing substantial disease globally. In this review, we will describe multiple approaches being undertaken to slow and control this spread of resistance. First, a number of old drugs have been repurposed and new drugs are being developed with activity against Neisseria gonorrhoeae. Second, vaccine development, long an important goal, is advancing. Third, new diagnostics promise rapid detection of antibiotic resistance and a shift from empiric to tailored treatment. The deployment of these new tools for addressing the challenge of antibiotic resistance will require careful consideration to provide optimal care for all patients while extending the lifespan of treatment regimens.

Commensal Neisseria Are Shared between Sexual Partners: Implications for Gonococcal and Meningococcal Antimicrobial Resistance

Antimicrobial resistance in pathogenic Neisseria parallels reduced antimicrobial susceptibility in commensal Neisseria in certain populations, like men who have sex with men (MSM). Although this reduced susceptibility can be a consequence of frequent antimicrobial exposure at the individual level, we hypothesized that commensal Neisseria are transmitted between sexual partners. We used data from a 2014 microbiome study in which saliva and tongue swabs were taken from 21 couples (42 individuals). Samples were analyzed using 16S rRNA gene sequencing. We compared intimate partners with unrelated individuals and found that the oral Neisseria communities of intimate partners were more similar than those of unrelated individuals (average Morisita-Horn dissimilarity index for saliva samples: 0.54 versus 0.71, respectively (p = 0.005); and for tongue swabs: 0.42 versus 0.63, respectively (p = 0.006)). This similarity presumably results from transmission of oral Neisseria through intimate kissing. This finding suggests that intensive gonorrhea screening in MSM may, via increased antimicrobial exposure, promote, rather than prevent, the emergence and spread of antimicrobial resistance in Neisseria. Non-antibiotic strategies such as vaccines and oral antiseptics could prove more sustainable options to reduce gonococcal prevalence.

Seasonal variations in kissing and sexual activities among men who have sex with men in Melbourne, Australia: implications for seasonal sexually transmissible infection preventions and interventions

Background Previous studies have shown that there is a peak in sexually transmissible infection (STI) cases and sexual activities around summer, but there has been no study examining whether kissing also follows a similar seasonal pattern. The aim of this study was to examine the seasonal patterns of kissing and sex partners among gay, bisexual and other men who have sex with men (MSM).

METHODS

A short cross-sectional study was conducted among MSM attending the Melbourne Sexual Health Centre between March 2016 and February 2017. Participants were asked to report the number of kissing-only, sex-only and kissing-with-sex male partners in the last 3 months. The mean number of male partners was calculated and stratified by Australia's seasons. The seasonal trend in the number of partners was assessed by negative binomial regression models.

RESULTS

In total, 4391 MSM were included in the analysis. The number of kissing-only and sex-only partners increased significantly from autumn to summer among MSM in Melbourne (Ptrend <0.001). MSM reported the highest number of male partners for kissing-only (mean: 4.91; 95% confidence intervals (CI): 4.78-5.04) and sex-only (mean: 1.91; 95% CI: 1.83-1.99) around summer compared with other seasons. However, the number of kissing-with-sex partners remained stable across seasons.

CONCLUSIONS

The study data suggest that there is a peak in kissing-only and sex-only partners among MSM around summer and holiday seasons.

Age, ethnic and travel-related disparities in kissing and sexual practices among heterosexual men in Melbourne, Australia

Background The kissing practices of heterosexual men are not well understood, despite the potential of kissing to be a significant risk factor for gonorrhoea transmission. This study aimed to explore kissing and sex practices among heterosexual men. Methods: A cross-sectional survey among heterosexual men attending the Melbourne Sexual Health Centre in 2016–2017 was conducted. Men were asked to report their number of kissing-only (in the absence of sex), sex-only (in the absence of kissing) and kissing-with-sex partners in the last 3 months. The mean number of each partner type was calculated, and multivariable negative binomial regression was used to investigate associations between the number of different types of partners and demographic characteristics. Results: Of the 2351 heterosexual men, men reported a mean of 2.98 kissing-only, 0.54 sex-only and 2.64 kissing-with-sex partners in the last 3 months. Younger men had a mean higher number of kissing-only partners than older men (4.52 partners among men aged ≤24 years compared with 1.75 partners among men ≥35 years, P &lt; 0.001). Men born in Europe had the most kissing-only partners (mean: 5.16 partners) and men born in Asia had the fewest kissing-only partners (mean: 1.61 partners). Men recently arrived in Australia, including travellers from overseas, had significantly more kissing-only partners (adjusted incidence rate ratio (aIRR): 1.53; 95% CI: 1.31–1.80) than local men. Conclusions: This study provides novel data about kissing practices of heterosexual men. Studies assessing oropharyngeal gonorrhoea should include measurements of kissing until studies can clarify its contribution to transmission risk.

Sexual practices of female sex workers in Melbourne, Australia: an anonymous cross-sectional questionnaire study in 2017-18

Background Sexually transmissible infections (STIs) are rising among female sex workers (FSW) in Australia. The rise might be explained by changes in sexual practices; however, there is limited behavioural data available. This study aimed to explore the current sexual practices among FSW in Melbourne.

METHODS

This cross-sectional study was conducted among FSW at Melbourne Sexual Health Centre between September 2017 and March 2018. Participants were asked about current sexual practices with male clients in an average working week. The frequency and proportion of each sexual practice was calculated.

RESULTS

There were 180 questionnaires included in the analysis. The median age of the FSW was 28 years (interquartile range [IQR]: 25-34). Most FSW (80.6%) worked in brothels. In an average working week, FSW had a median of 10 (IQR: 7-20) male clients. The most common sexual practices included: vaginal sex (98.3%), fellatio (97.2%), cunnilingus (92.2%) and tongue-kissing (83.7%). FSW had a median number of 10 (IQR: 6-18) vaginal, 10 (IQR: 5-18) fellatio, 7 (IQR: 2-10) cunnilingus and 6 (IQR: 2-10) tongue-kissing clients. Consistent condom use with all clients was highest for vaginal sex (97.1%), followed by anal sex (92.3%), then fellatio (78.9%). Only 3.1% used dental dams consistently for cunnilingus.

CONCLUSION

Consistent condom use with all clients was high among FSWs, especially for vaginal and anal sex. However, one-fifth of FSW had condomless fellatio during an average working week. Tongue-kissing was more common than previously published. Peer-led sexual health education on safe sex practice for FSW is of high importance.

Drug use and the influence on kissing among men who have sex with men in Melbourne, Australia

The use of drugs is not uncommon among gay, bisexual and other men who have sex with men (MSM). Kissing has been recently identified as a risk factor for gonorrhoea. This study aimed to examine the proportion of MSM who used drugs and how specific drugs influence the likelihood of kissing. We conducted a cross-sectional survey among MSM attending the Melbourne Sexual Health Centre between March 2016 and February 2017. Participants reported their use of eleven specific drugs in the last three months and whether they felt the drug influenced them to kiss someone. Four thousand, three hundred and ninety-one MSM were included in the analysis; 63.1% ( n =  2772) used at least one drug in the last three months and 36.6% ( n =  1605) used ≥2 drugs. Poppers (44.8%), marijuana (30.8%) and ecstasy (19.1%) were the three most common drugs used among MSM in the last three months. 80.4% of ecstasy users and 74.3% of gammahydroxybutyrate users reported the drug made them much more likely to kiss someone. The majority of MSM reported that the use of heroin (63.6%) and Viagra/Cialis (60.7%) did not influence their kissing behaviour. Drug use is common among sexually active MSM in Melbourne. Most reported the use of ecstasy would increase their likelihood of kissing someone.

Only recent sexual partners contribute to oropharyngeal gonorrhoea positivity: the number of sexual partners over different time periods as an indicator of gonorrhoea and chlamydia infection duration among men who have sex with men

Background Mathematical models have demonstrated that the majority of gonococcal transmission is from oropharynx to oropharynx (i.e. kissing) among men who have sex with men (MSM). The aim of this study is to investigate the association between the number of partners within specific time periods and gonorrhoea and chlamydia positivity.

METHODS

This was a retrospective data analysis of MSM attending the Melbourne Sexual Health Centre between 2007 and 2016. Univariable and multivariable logistic regression analyses, with generalised estimating equations (GEE), were performed to determine if the number of partners within specified time periods was associated with site-specific gonorrhoea and chlamydia positivity.

RESULTS

There were 45933 consultations which included 15197 MSM. Oropharyngeal gonorrhoea positivity was associated with the number of partners in the past 3 months, but not the number of partners 4-12 months ago; men who had ≥6 partners in the past 3 months had significantly higher odds of acquiring oropharyngeal gonorrhoea (aOR 1.93; 95% CI 1.61-2.31), but this was not the case for men who had ≥6 partners 4-12 months ago. Anorectal gonorrhoea and chlamydia and urethral chlamydia were associated with the number of partners in both time periods after adjusting for age and condom use.

CONCLUSIONS

The association of oropharyngeal gonorrhoea with the number of recent partners, but not partners from an earlier period, unlike anorectal gonorrhoea and anorectal and urethral chlamydia, could be explained by a shorter duration of oropharyngeal gonococcal infection. Annual screening for gonorrhoea may be insufficient to materially reduce oropharyngeal prevalence.

Effects of Pre-exposure Prophylaxis for the Prevention of Human Immunodeficiency Virus Infection on Sexual Risk Behavior in Men Who Have Sex With Men: A Systematic Review and Meta-analysis

Background

Human immunodeficiency virus (HIV) pre-exposure prophylaxis (PrEP) is effective in reducing HIV risk in men who have sex with men (MSM). However, concerns remain that risk compensation in PrEP users may lead to decreased condom use and increased incidence of sexually transmitted infections (STIs). We assessed the impact of PrEP on sexual risk outcomes in MSM.

Methods

We conducted a systematic review of open-label studies published to August 2017 that reported sexual risk outcomes in the context of daily oral PrEP use in HIV-negative MSM and transgender women. Pooled effect estimates were calculated using random-effects meta-analysis, and a qualitative review and risk of bias assessment were performed.

Results

Sixteen observational studies and 1 open-label trial met selection criteria. Eight studies with a total of 4388 participants reported STI prevalence, and 13 studies with a total of 5008 participants reported change in condom use. Pre-exposure prophylaxis use was associated with a significant increase in rectal chlamydia (odds ratio [OR], 1.59; 95% confidence interval [CI], 1.19-2.13) and an increase in any STI diagnosis (OR, 1.24; 95% CI, .99-1.54). The association of PrEP use with STI diagnoses was stronger in later studies. Most studies showed evidence of an increase in condomless sex among PrEP users.

Conclusion

Findings highlight the importance of efforts to minimize STIs among PrEP users and their sexual partners. Monitoring of risk compensation among MSM in the context of PrEP scale-up is needed to assess the impact of PrEP on the sexual health of MSM and to inform preventive strategies.

Sites in the oropharynx reached by different methods of using mouthwash: clinical implication for oropharyngeal gonorrhoea prevention

OBJECTIVES

Oropharyngeal gonorrhoea is increasing among men who have sex with men and is commonly found in the tonsils and at the posterior pharyngeal wall. To address this rise, investigators are currently trialling mouthwash to prevent oropharyngeal gonorrhoea. We aimed to determine which parts of the oropharynx were reached by different methods of mouthwash use (oral rinse, oral gargle and oral spray).

METHODS

Twenty staff at Melbourne Sexual Health Centre participated in the study from March to May 2018. Participants were asked to use mouthwash mixed with food dye, by three application methods on three separate days: oral rinse (15 s and 60 s), oral gargle (15 s and 60 s) and oral spray (10 and 20 times). Photographs were taken after using each method. Three authors assessed the photographs of seven anatomical areas (tongue base, soft palate, uvula, anterior tonsillar pillar, posterior tonsillar pillar, tonsil, posterior pharyngeal wall) independently and scored the dye coverage from 0% to 100%. Scores were then averaged.

RESULTS

The mean coverage at the sites ranged from 2 to 100. At the posterior pharyngeal wall, spraying 10 times had the highest mean coverage (29%) and was higher than a 15 s rinse (2%, p=0.001) or a 15 s gargle (8%, p=0.016). At the tonsils, there was no difference in mean coverage between spray and gargle at any dosage, but spraying 20 times had a higher mean coverage than a 15 s rinse (42% vs 12%, p=0.012).

CONCLUSION

Overall, spray is more effective at reaching the tonsils and posterior pharyngeal wall compared with rinse and gargle. If mouthwash is effective in preventing oropharyngeal gonorrhoea, application methods that have greater coverage may be more efficacious.

The development of mouthwashes without anti-gonococcal activity for controlled clinical trials: an in vitro study

Background: The oropharynx plays a major role in the development and spread of antimicrobial resistant Neisseria gonorrhoeae among men who have sex with men. Trials are currently assessing the efficacy of bactericidal mouthwashes as possible therapeutic or preventive options against these pharyngeal gonococcal infections. Controlled clinical trials require the use of a placebo mouthwash without anti-gonococcal activity. So far, no such placebo mouthwash has been described. We describe the development of a mouthwash for this purpose.

Methods: The in vitro anti-gonococcal activity of Corsodyl®, Listerine Cool Mint®, Biotene®, phosphate buffered saline and six in-house placebo mouthwashes was evaluated. Three gonococcal isolates from patients with pharyngeal infection were exposed to the mouthwashes for a duration ranging from 30 seconds to 60 minutes. Isolates were then plated in duplicate onto blood agar (5% horse blood) and incubated for 24 hours (5-7% CO ₂, 35 ± 2°C). Growth of N. gonorrhoeae was scored on a five-point scale (0 = no growth, to 4 = confluent growth of colonies).

Results: Corsodyl® and Listerine Cool Mint® were bactericidal to all isolates. For the other mouthwashes, the median growth score after 60 minutes of exposure was 4 (interquartile range 4-4) for phosphate buffered saline; 1 (interquartile range 1-3) for Biotene®; and ranged between 0 and 2 for the in-house composed mouthwashes. An in-house composed mouthwash (Placebo 6) performed best, with a growth score of 2.5 (interquartile range 1-3).

Conclusions: All the evaluated potential placebo mouthwashes were bacteriostatic after gonococcal exposure of 30 to 60 minutes. In-house composed Placebo 6 showed less inhibition on gonococcal growth than Biotene® and the other in-house placebos and demonstrates, in our opinion, a good trade-off between anti-gonococcal properties and taste.

New thinking on gonorrhoea control in MSM: are antiseptic mouthwashes the answer?

PURPOSE OF REVIEW

The rate of gonorrhoea is rising and is much higher in men who have sex with men (MSM) than heterosexuals. The purpose of this review was to describe research supporting a new paradigm of transmission of gonorrhoea in MSM and interventions that may result from this.

RECENT FINDINGS

Evidence is accumulating that gonorrhoea in MSM is transmitted differently than previously thought and that asymptomatic sites of infection may play a major role in the persistent of gonorrhoea at a population level. Saliva commonly contains gonorrhoea, and saliva is commonly used during sexual acts. Both in-vitro, in-vivo studies have suggested that antibacterial mouthwash may reduce gonorrhoea at the oropharynx. A recently published mathematical model also suggests that if mouthwash were effective, it would result in considerable declines in the community prevalence in MSM.

SUMMARY

A newly suggested paradigm for the transmission of gonorrhoea in MSM could potentially offer a simple condom-free control strategy. But considerable more research is required before it could be recommended even if it were shown to be effective in a clinical trial.

Models of gonorrhoea transmission from the mouth and saliva

This Personal View argues for a new framework of gonorrhoea transmission in men who have sex with men in which the oropharynx plays a major role in transmitting gonorrhoea to, or acquiring gonorrhoea from, their partner's oropharynx, penis, or anorectum through either direct contact or via saliva. To avoid preconceived notions of transmission dynamics, we ask readers to imagine that they are investigating a new sexually transmitted infection. On the basis of the existing clinical and epidemiological data for gonorrhoea at the penis, oropharynx, and anorectum site, we develop two models for transmission: the so-called penile model and the so-called oropharyngeal model. We argue that the existing epidemiological data and behavioural data best fit the oropharyngeal model. Our argument rests on the observation that, at the population level, the prevalence of urethral gonorrhoea is too rare to explain the high incidence of oropharynx and anorectum infection. We describe studies of gonorrhoea detection in saliva, saliva use during sex, epidemiological studies of kissing and oropharyngeal gonorrhoea, as well as studies aided by mathematical models. Finally, we argue that the correlation between sexual acts (eg, kissing, oral sex, anal sex, and saliva use) is so high that any epidemiological study that does not measure these factors will be prone to confounding.

Prevalence of genital and oropharyngeal chlamydia and gonorrhoea among female sex workers in Melbourne, Australia, 2015-2017: need for oropharyngeal testing

OBJECTIVE

The Victorian legislation requires sex workers to have quarterly screening for genital chlamydia and gonorrhoea, but screening for oropharyngeal infection is not mandatory in Victoria, Australia. In 2017, oropharyngeal screening for gonorrhoea and chlamydia was added as part of the routine quarterly screening for sex workers attending the Melbourne Sexual Health Centre (MSHC). The aim of this study was to examine the prevalence of oropharyngeal gonorrhoea and chlamydia among female sex workers (FSW).

METHODS

We included females who (1) self-identified as sex workers or were attended MSHC for a sex work certificate and (2) had tested for any STI or HIV, between March 2015 and December 2017. The prevalence of HIV, syphilis, chlamydia and gonorrhoea was calculated.

RESULTS

There were 8538 FSW consultations among 2780 individuals during the study period. There was a twofold increase in genital gonorrhoea (from 0.5% (95% CI 0.3% to 0.9%) to 1.1% (95% CI 0.8% to 1.5%); p_trend=0.047) and a 1.5-fold increase in genital chlamydia (from 2.2% (95% CI 1.6% to 2.8%) to 3.2% (95% CI 2.6% to 3.8%); p_trend=0.031) during the period. Overall, the prevalence of HIV (0.2% (95% CI 0.1% to 0.3%)) and syphilis (0.1% (95% CI 0.0% to 0.2%)) remained low and did not change over time. In 2017, the prevalence of oropharyngeal gonorrhoea was 2.0% (95% CI 1.6% to 2.6%) and oropharyngeal chlamydia was 2.1% (95% CI 1.6% to 2.7%). Among FSW who were tested positive for gonorrhoea and chlamydia, 55% (n=41) and 34% (n=45) only tested positive in the oropharynx but not genital for gonorrhoea and chlamydia, respectively.

CONCLUSION

The prevalence of oropharyngeal gonorrhoea and chlamydia is similar to the prevalence at genital sites and is often independent of genital infection. It is important to test the oropharynx and genital site for chlamydia and gonorrhoea among FSW.

Kissing may be an important and neglected risk factor for oropharyngeal gonorrhoea: a cross-sectional study in men who have sex with men

OBJECTIVES

A mathematical model suggested that a significant proportion of oropharyngeal gonorrhoea cases are acquired via oropharynx-to-oropharynx transmission (ie, tongue-kissing), but to date, no empirical study has investigated this. This study aimed to examine the association between kissing and oropharyngeal gonorrhoea among gay and bisexual men who have sex with men (MSM).

METHODS

MSM attending a public sexual health centre in Melbourne, Australia, between March 2016 and February 2017 were invited to participate in a brief survey that collected data on their number of male partners in the last 3 months, in three distinct categories: kissing-only (ie, no sex including no oral and/or anal sex), sex-only (ie, any sex without kissing), and kissing-with-sex (ie, kissing with any sex). Univariable and multivariable logistic regression analyses were performed to examine associations between oropharyngeal gonorrhoea positivity by nucleic acid amplification tests and the three distinct partner categories.

RESULTS

A total of 3677 men completed the survey and were tested for oropharyngeal gonorrhoea. Their median age was 30 (IQR 25-37) and 6.2% (n=229) had oropharyngeal gonorrhoea. Men had a mean number of 4.3 kissing-only, 1.4 sex-only, and 5.0 kissing-with-sex partners in the last 3 months. Kissing-only and kissing-with-sex were associated with oropharyngeal gonorrhoea, but sex-only was not. The adjusted odds for having oropharyngeal gonorrhoea were 1.46-fold (95% CI 1.04 to 2.06) for men with ≥4 kissing-only partners and 1.81-fold (95% CI 1.17 to 2.79) for men with ≥4 kissing-with-sex partners.

CONCLUSIONS

These data suggest that kissing may be associated with transmission of oropharyngeal gonorrhoea in MSM, irrespective of whether sex also occurs.

Construction and optimization of a 'NG Morbidostat' - An automated continuous-culture device for studying the pathways towards antibiotic resistance in Neisseria gonorrhoeae

To obtain a detailed picture of the dynamics of antibiotic resistance development in Neisseria gonorrhoeae, we built a morbidostat according to the protocol of Toprak et al., adjusted to the specific characteristics required for the growth of N. gonorrhoeae. In this article we describe the adaptations, specifications and the difficulties we encountered during the construction and optimization of the NG morbidostat. As a proof of concept, we conducted a morbidostat experiment by increasing concentrations of azithromycin in response to bacterial growth. We started the experiment with two N. gonorrhoeae reference strains WHO-F and WHO-X. These strains were grown in 12 mL GC Broth supplemented with IsoVitaleX™ (1%) and vancomycin, colistin, nystatin, trimethoprim (VCNT) selective supplement for 30 days in a 6% CO ₂ environment at 36°C. Samples of the cultures were taken 2-3 times a week and minimal inhibitory concentrations (MICs) of azithromycin were determined using E-test. The initial MICs of WHO-F and WHO-X were 0.125 µg/mL and 0.25 µg/mL, respectively. In less than 30 days, we were able to induce high level azithromycin resistance in N. gonorrhoeae, with a 750 and 1000 fold increase in MIC for WHO-F and WHO-X, respectively.

Construction and optimization of a 'NG Morbidostat' - An automated continuous-culture device for studying the pathways towards antibiotic resistance in Neisseria gonorrhoeae

To obtain a detailed picture of the dynamics of antibiotic resistance development in Neisseria gonorrhoeae, we built a morbidostat according to the protocol of Toprak et al., adjusted to the specific characteristics required for the growth of N. gonorrhoeae. In this article we describe the adaptations, specifications and the difficulties we encountered during the construction and optimization of the NG morbidostat. As a proof of concept, we conducted a morbidostat experiment by increasing concentrations of azithromycin in response to bacterial growth. We started the experiment with two N. gonorrhoeae reference strains WHO-F and WHO-X. These strains were grown in 12 mL GC Broth supplemented with IsoVitaleX™ (1%) and vancomycin, colistin, nystatin, trimethoprim (VCNT) selective supplement for 30 days in a 6% CO 2 environment at 36°C. Samples of the cultures were taken 2-3 times a week and minimal inhibitory concentrations (MICs) of azithromycin were determined using E-test. The initial MICs of WHO-F and WHO-X were 0.125 µg/mL and 0.25 µg/mL, respectively. In less than 30 days, we were able to induce high level azithromycin resistance in N. gonorrhoeae, with a 750 and 1000 fold increase in MIC for WHO-F and WHO-X, respectively.

Epidemiology and prevention of sexually transmitted infections in men who have sex with men at risk of HIV

Since 2012, the increasingly widespread promotion and uptake of HIV treatment as prevention and pre-exposure prophylaxis in men who have sex with men has been associated with increased sexually transmitted infections (STIs). However, numbers of STI cases have been rising for more than 20 years and the introduction of biomedical HIV interventions cannot explain the majority of the rises in STIs. The increases appear to have occurred mostly because of gradual changes in behaviour over many years, coupled in some settings with more condomless anal intercourse, and as a result of the increased screening for previously undetected asymptomatic infections. If control of STIs is to be improved, then a far greater emphasis on increased use of existing effective STI control strategies will be required, in addition to the investigation of new interventions. Central to effective STI control is accessible clinical care and screening services, which are currently inadequate in most settings. Insufficient action carries a risk of increased STI epidemics, including of newly resistant organisms.

Evidence for a new paradigm of gonorrhoea transmission: cross-sectional analysis of Neisseria gonorrhoeae infections by anatomical site in both partners in 60 male couples

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.

Concordance of gonorrhoea of the rectum, pharynx and urethra in same-sex male partnerships attending a sexual health service in Melbourne, Australia

BACKGROUND

We aimed to describe anatomic site-specific concordance of gonococcal infections in partnerships of men who have sex with men (MSM).

METHODS

We conducted a cross-sectional analysis of data from MSM partnerships attending Melbourne Sexual Health Centre between March 2011 and February 2015. Logistic regression models (random effect) were used to examine the association between gonococcal infections of the urethra, rectum and pharynx. Gonococci were detected by culture at all anatomic sites.

RESULTS

The analysis included 495 partnerships. Of the men with urethral gonorrhoea, 33% (95% CI 18-52) had partners with pharyngeal gonorrhoea and 67% (95% CI 48-82) had partners with rectal gonorrhoea. The adjusted odds of having urethral gonorrhoea was 4.6 (95% CI 1.2-17.1) for a man whose partner had pharyngeal gonorrhoea, and 48.1 (95% CI 18.3-126.7) for a man whose partner had rectal gonorrhoea. Of the men with rectal gonorrhoea, 46% (95% CI 31-61) had a partner with urethral gonorrhoea and 23% (95% CI 12-37) had a partner with pharyngeal gonorrhoea. The adjusted odds of having rectal gonorrhoea was 63.9 (95% CI 24.7-165.6) for a man whose partner had urethral gonorrhoea. Of the men with pharyngeal gonorrhoea, 42% (95% CI 23-63) had a partner with rectal gonorrhoea and 23% (95% CI 9-44) had a partner with had a partner with pharyngeal gonorrhoea. The adjusted odds of having pharyngeal gonorrhoea was 8.9 (95% CI 3.2-24.6) for a man whose partner had rectal gonorrhoea. The crude odds of having pharyngeal gonorrhoea was 14.2 (95% CI 5.1-39.0) for a man whose partner had pharyngeal gonorrhoea.

CONCLUSIONS

These data provide the first estimates of concordance of anatomic site-specific gonococcal infections in MSM partnerships, and confirm that urethral gonorrhoea is contracted from both rectal and pharyngeal sites, and suggest that gonococci transmit between the rectum and pharynx. However, due to use of culture rather than NAAT, our analysis was not adequately powered to assess pharynx-to-pharynx transmission of gonococci.

Risk factors for oropharyngeal gonorrhoea in men who have sex with men: an age-matched case-control study

OBJECTIVES

Oropharyngeal gonorrhoea is common among men who have sex with men (MSM). We aimed to clarify which oral sex practices were independent risk factors for oropharyngeal gonorrhoea: tongue kissing, receptive oro-penile sex (fellatio) or insertive oro-anal sex (rimming), and whether daily use of mouthwash and recent antibiotic use was protective.

METHODS

In 2015, we conducted an age-matched case-control study of MSM who attended the Melbourne Sexual Health Centre. Cases had tested positive for oropharyngeal gonorrhoea by nucleic acid amplification testing, and controls had tested negative. Questionnaire items included tongue kissing, oral sex practices, condom use, recent antibiotic use, mouthwash use and alcohol consumption.

RESULTS

We identified 177 cases, age matched to 354 controls. In univariable analyses, cases were 1.90 times (95% CI 1.13 to 3.20) more likely than controls to have had casual sexual partners (CSP) in the preceding 3 months, were 2.17 times (95% CI 1.31 to 3.59) more likely to have kissed CSP and were 2.04 times (95% CI 1.26 to 3.30) more likely to have had receptive oro-penile sex with CSP. Oropharyngeal gonorrhoea was not associated with insertive oro-anal sex or mouthwash use. The number of CSP for tongue kissing and receptive oral sex and total CSP were highly correlated, and in multivariable analysis neither kissing nor receptive oro-penile sex was significantly associated with having oropharyngeal gonorrhoea, after adjusting for total number of CSP.

CONCLUSIONS

The finding that oropharyngeal gonorrhoea was associated with a higher number of sexual partners but not specific sexual practices highlights the need for further research in the area of gonorrhoea transmission to define the probability of transmission from specific sex acts.

The frequency of kissing as part of sexual activity differs depending on how men meet their male casual sexual partners

Previous studies have shown that men who have sex with men (MSM) who use smartphone dating applications (apps) are at higher risk of gonorrhoea, but not HIV. We have hypothesised that kissing may be a risk factor for oropharyngeal gonorrhoea. We measured differences in kissing practices among MSM who use different methods to find male casual sexual partners (CSPs). If MSM who use apps kiss more CSPs, then this may help to explain why these men are at increased risk of gonorrhoea but not HIV. This was a cross-sectional questionnaire-based study of MSM attending Melbourne Sexual Health Centre, Australia, between March and September 2015. We measured differences in kissing practices among MSM who use different methods to find male casual sexual partners (CSPs). The questionnaire included questions about numbers of CSPs, numbers of CSPs kissed, and how men found CSPs. We surveyed 753 MSM with a median age of 29 years (interquartile range 25-36). Six hundred and one men (79.8%) reported using apps to find CSPs in the last three months. Users of apps had a higher number of CSPs than non-users (5.0 vs. 3.2; p < 0.001). Users of apps kissed a higher number (4.6 vs. 2.2; p < 0.001), and a higher proportion (90.4% vs. 71.0%; p < 0.001) of CSPs compared to non-users. We are currently investigating whether kissing is a significant mode of transmission of gonorrhoea, and if this proves correct then this study suggests that users of apps would particularly benefit from health promotion that addresses this mode of transmission.