Antiseptic mouthwash against pharyngeal Neisseria gonorrhoeae: a randomised controlled trial and an in vitro study

The Discovery of Oropharyngeal Microbiota with Inhibitory Activity against Pathogenic Neisseria gonorrhoeae and Neisseria meningitidis: An In Vitro Study of Clinical Isolates

With increasing incidence of pathogenic Neisseria infections coupled with emerging resistance to antimicrobials, alternative approaches to limit the spread are sought. We investigated the inhibitory effect of oropharyngeal microbiota on the growth of N. gonorrhoeae and N. meningitidis and the impact of the essential oil-based mouthwash Listerine Cool Mint^® (Listerine). Oropharyngeal swabs from 64 men who have sex with men (n = 118) from a previous study (PReGo study) were analysed (ClinicalTrials.gov, NCT03881007). These included 64 baseline and 54 samples following three months of daily use of Listerine. Inhibition was confirmed by agar overlay assay, and inhibitory bacteria isolated using replica plating and identified using MALDI-TOF. The number of inhibitory isolates were compared before and after Listerine use. Thirty-one pharyngeal samples (26%) showed inhibitory activity against N. gonorrhoeae and/or N. meningitidis, and 62 inhibitory isolates were characterised. Fourteen species belonging to the genera Streptococci and Rothia were identified. More inhibitory isolates were observed following Listerine use compared to baseline, although this effect was not statistically significant (p = 0.073). This study isolated and identified inhibitory bacteria against pathogenic Neisseria spp. and established that daily Listerine use did not decrease their prevalence. These findings could provide a new approach for the prevention and treatment of pharyngeal Neisseria infections.

Non-conventional interventions to prevent gonorrhea or syphilis among men who have sex with men: A scoping review

Objectives

We assessed nonconventional interventions that did not traditionally focus on increasing condom use and/or testing among men who have sex with men (MSM) and the evidence for these interventions.

Methods

Guided by the Participants, Concept and Context (PCC) framework, we searched five online databases from inception to 9 August 2021 for original research on interventions that do not focus on increasing condom use and/or testing to prevent gonorrhea and/or syphilis in MSM. Two researchers screened titles and abstracts to assess eligibility, reviewed articles' full text and resolved discrepancies through discussion. We charted relevant study information, and the included studies were critically appraised.

Results

Of 373 articles retrieved, 13 studies were included. These studies were conducted in Australia (n = 3), Belgium (n = 2), China (n = 3), the Netherlands (n = 1) and the US (n = 4). Two randomized controlled trials (RCTs) of doxycycline as pre-exposure prophylaxis (PrEP) and post-exposure prophylaxis (PEP) reduced any STI incidence (gonorrhea, syphilis, or chlamydia), but only doxycycline PEP significantly reduced syphilis incidence. Six studies of interventions that facilitated self-collection, self-examination, and self-testing, found varied evidence for gonorrhea and/or syphilis prevention. Four RCTs and one single-arm trial examined the efficacy of mouthwash, but the evidence remains inconclusive on whether mouthwash use can prevent transmission between men.

Conclusion

We found evidence for doxycycline PEP in reducing syphilis incidence, evidence on the use of mouthwash to prevent gonorrhea transmission between men remains inconclusive. More evidence is needed for interventions that do not focus on increasing condom use and/or testing to prevent gonorrhea and/or syphilis.

The SARS-CoV2 envelope differs from host cells, exposes procoagulant lipids, and is disrupted in vivo by oral rinses

The lipid envelope of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an essential component of the virus; however, its molecular composition is undetermined. Addressing this knowledge gap could support the design of antiviral agents as well as further our understanding of viral-host protein interactions, infectivity, pathogenicity, and innate immune system clearance. Lipidomics revealed that the virus envelope comprised mainly phospholipids (PLs), with some cholesterol and sphingolipids, and with cholesterol/phospholipid ratio similar to lysosomes. Unlike cellular membranes, procoagulant amino-PLs were present on the external side of the viral envelope at levels exceeding those on activated platelets. Accordingly, virions directly promoted blood coagulation. To investigate whether these differences could enable selective targeting of the viral envelope in vivo, we tested whether oral rinses containing lipid-disrupting chemicals could reduce infectivity. Products containing PL-disrupting surfactants (such as cetylpyridinium chloride) met European virucidal standards in vitro; however, components that altered the critical micelle concentration reduced efficacy, and products containing essential oils, povidone-iodine, or chlorhexidine were ineffective. This result was recapitulated in vivo, where a 30-s oral rinse with cetylpyridinium chloride mouthwash eliminated live virus in the oral cavity of patients with coronavirus disease 19 for at least 1 h, whereas povidone-iodine and saline mouthwashes were ineffective. We conclude that the SARS-CoV-2 lipid envelope i) is distinct from the host plasma membrane, which may enable design of selective antiviral approaches; ii) contains exposed phosphatidylethanolamine and phosphatidylserine, which may influence thrombosis, pathogenicity, and inflammation; and iii) can be selectively targeted in vivo by specific oral rinses.

Inhibitory Activity of Antibacterial Mouthwashes and Antiseptic Substances against Neisseria gonorrhoeae

Improved treatment and prevention strategies, such as antimicrobial mouthwashes, may be important for addressing the public health threat of antimicrobial-resistant Neisseria gonorrhoeae. Here, we describe the activity of seven common antibacterial mouthwashes and antiseptics against N. gonorrhoeae isolates, incorporating the use of a human saliva test matrix. Our data demonstrate that antibacterial mouthwashes and antiseptics vary in their ability to inhibit the in vitro growth of N. gonorrhoeae and saliva may impact this inhibitory activity.

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.

A cross-sectional study of male and female kissing partners among men who have sex with men

BACKGROUND

Kissing may be a risk factor for gonorrhoea. Past studies have focused on male kissing partners among men who have sex with men (MSM). This study aimed to examine the kissing practices of MSM who kiss male and female partners.

METHODS

We conducted a cross-sectional survey at the Melbourne Sexual Health Centre (MSHC) between March and April 2019. Men attending the MSHC, aged ≥16years who reported any sexual contact with another man in the previous 12months were invited to participate in the survey. Data about the number of kissing-only (kissing without sex), kissing-with-sex, and sex-only (having sex without kissing) partners in the previous 3months were collected. Men were asked to report the number of male and female partners separately.

RESULTS

There were 357 MSM included in the survey. Most men (97.2%, n=347) had kissed or had sex with another man, whereas 16.0% (n=57) had kissed or had sex with a female partner in the previous 3months. Of the 57 men, 26.3% (n=15) had only kissed a female partner without having sex. The mean number of male partners for kissing-only was 5.5 (s.d.=6.6), kissing-with-sex was 5.0 (s.d.=6.6) and sex-only was 3.9 (s.d.=4.3). The mean number of female partners for kissing-only was 4.2 (s.d.=6.9), kissing-with-sex was 3.8 (s.d.=4.9) and sex-only was 3.2 (s.d.=3.4).

CONCLUSION

MSM not only kiss men in the absence of sex, but also kiss women in the absence of sex. Gonorrhoea could be transmitted between MSM and women via kissing in the absence of sex.

Neisseria mucosa Does Not Inhibit the Growth of Neisseria gonorrhoeae

Antibiotic-sparing treatments are required to prevent the further emergence of antimicrobial resistance in Neisseria gonorrhoeae. Commensal Neisseria species have previously been found to inhibit the growth of pathogenic Neisseria species. For example, a previous study found that three out of five historical isolates of Neisseria mucosa could inhibit the growth of N. gonorrhoeae. In this study, we used agar overlay assays to assess if 24 circulating and historical isolates of Neisseria mucosa could inhibit the growth of 28 circulating and historical isolates of N. gonorrhoeae. Although pitting around each colony of N. mucosa created an optical illusion of decreased growth of N. gonorrhoeae, we found no evidence of inhibition (n = 24). In contrast, positive controls of Streptococcus pneumoniae and Escherichia coli demonstrated a strong inhibitory effect against the growth of N. gonorrhoeae.

Chlorhexidine Mouthwash Fails to Eradicate Oropharyngeal Gonorrhea in a Clinical Pilot Trial (MoNg)

ABSTRACT

This single-arm open-label pilot trial in Antwerp, Belgium, was ended early in accordance with the protocol because twice-daily gargling with chlorhexidine 0.2% for 6 days failed to eradicate Neisseria gonorrhoeae from the oropharynx of asymptomatic men who have sex with men (n = 3; efficacy of 0%; 95% confidence interval, 0%-56.1%).

The Impact of Mouthwash on the Oropharyngeal Microbiota of Men Who Have Sex with Men: a Substudy of the OMEGA Trial

Mouthwash is a commonly used product and has been proposed as an alternative intervention to prevent gonorrhea transmission. However, the long-term effects of mouthwash on the oral microbiota are largely unknown. We investigated the impact of 12 weeks of daily mouthwash use on the oropharyngeal microbiota in a subset of men who have sex with men who participated in a randomized trial comparing the efficacy of two alcohol-free mouthwashes for the prevention of gonorrhea. We characterized the oropharyngeal microbiota using 16S rRNA gene sequencing of tonsillar fossae samples collected before and after 12 weeks of daily use of Listerine mouthwash or Biotène dry mouth oral rinse. Permutational multivariate analysis of variance (PERMANOVA) was used to assess differences in oropharyngeal microbiota composition following mouthwash use. Differential abundance testing was performed using ALDEx2, with false-discovery rate correction. A total of 306 samples from 153 men were analyzed (Listerine, n = 78 and Biotène, n = 75). There was no difference in the overall structure of the oropharyngeal microbiota following Listerine or Biotène use (PERMANOVA P = 0.413 and P = 0.331, respectively). Although no bacterial taxa were significantly differentially abundant following Listerine use, we observed a small but significant decrease in the abundance of both Streptococcus and Leptotrichia following Biotène use. Overall, our findings suggest that daily use of antiseptic mouthwash has minimal long-term effects on the composition of the oropharyngeal microbiota.

IMPORTANCE Given the role of the oral microbiota in human health, it is important to understand if and how external factors influence its composition. Mouthwash use is common in some populations, and the use of antiseptic mouthwash has been proposed as an alternative intervention to prevent gonorrhea transmission. However, the long-term effect of mouthwash use on the oral microbiota composition is largely unknown. We found that daily use of two different commercially available mouthwashes had limited long-term effects on the composition of the oropharyngeal microbiota over a 12-week period. The results from our study and prior studies highlight that different mouthwashes may differentially affect the oral microbiome composition and that further studies are needed to determine if mouthwash use induces short-term changes to the oral microbiota that may have detrimental effects.

Sub-Inhibitory Concentrations of Chlorhexidine Induce Resistance to Chlorhexidine and Decrease Antibiotic Susceptibility in Neisseria gonorrhoeae

Objectives: Chlorhexidine digluconate (chlorhexidine) and Listerine^® mouthwashes are being promoted as alternative treatment options to prevent the emergence of antimicrobial resistance in Neisseria gonorrhoeae. We performed in vitro challenge experiments to assess induction and evolution of resistance to these two mouthwashes and potential cross-resistance to other antimicrobials.

Methods: A customized morbidostat was used to subject N. gonorrhoeae reference strain WHO-F to dynamically sustained Listerine^® or chlorhexidine pressure for 18 days and 40 days, respectively. Cultures were sampled twice a week and minimal inhibitory concentrations (MICs) of Listerine^®, chlorhexidine, ceftriaxone, ciprofloxacin, cefixime and azithromycin were determined using the agar dilution method. Isolates with an increased MIC for Listerine^® or chlorhexidine were subjected to whole genome sequencing to track the evolution of resistance.

Results: We were unable to increase MICs for Listerine^®. Three out of five cultures developed a 10-fold increase in chlorhexidine MIC within 40 days compared to baseline (from 2 to 20 mg/L). Increases in chlorhexidine MIC were positively associated with increases in the MICs of azithromycin and ciprofloxacin. Low-to-higher-level chlorhexidine resistance (2–20 mg/L) was associated with mutations in NorM. Higher-level resistance (20 mg/L) was temporally associated with mutations upstream of the MtrCDE efflux pump repressor (mtrR) and the mlaA gene, part of the maintenance of lipid asymmetry (Mla) system.

Conclusion: Exposure to sub-lethal chlorhexidine concentrations may not only enhance resistance to chlorhexidine itself but also cross-resistance to other antibiotics in N. gonorrhoeae. This raises concern regarding the widespread use of chlorhexidine as an oral antiseptic, for example in the field of dentistry.

Novel strategies for prevention and treatment of antimicrobial resistance in sexually-transmitted infections

PURPOSE OF REVIEW

Antimicrobial resistance in sexually acquired infection (STI) pathogens is an important global public health threat. There is an urgent need for novel STI treatment and prevention strategies to tackle the rising incidence of STIs in high-income settings and the static progress in low- and middle-income settings over the past decade. The purpose of this review was to describe the research outlining the emergence of resistance in common STI pathogens and new strategies for their treatment and prevention.

RECENT FINDINGS

Rates of STIs have dramatically increased over the past decade. Further, antimicrobial resistance to first-line agents among key STI pathogens continues to emerge globally. Recent findings demonstrate promising results regarding the efficacy of novel antimicrobial treatment strategies for these pathogens, including several new, repurposed and unique combinations of antimicrobials. In addition, a number of new biomedical prevention strategies, such as antibacterial mouthwash and doxycycline chemoprophylaxis, are being investigated as novel prevention strategies for bacterial STIs.

SUMMARY

Significant progress has been made in the development of novel antimicrobials for the treatment of antimicrobial-resistant sexually acquired pathogens. However, due to the rapid development of resistance to antimicrobials demonstrated by these pathogens in the past, further research and development of effective prevention strategies should be prioritized.

Potential effect of antiseptic mouthwash on the incidence of Neisseria gonorrhoeae among men who have sex with men: a mathematical modelling study

OBJECTIVES

The incidence of Neisseria gonorrhoeae and its antimicrobial resistance is increasing in many countries. Antibacterial mouthwash may reduce gonorrhoea transmission without using antibiotics. We modelled the effect that antiseptic mouthwash may have on the incidence of gonorrhoea.

DESIGN

We developed a mathematical model of the transmission of gonorrhoea between each anatomical site (oropharynx, urethra and anorectum) in men who have sex with men (MSM). We constructed four scenarios: (1) mouthwash had no effect; (2) mouthwash increased the susceptibility of the oropharynx; (3) mouthwash reduced the transmissibility from the oropharynx; (4) the combined effect of mouthwash from scenarios 2 and 3.

SETTING

We used data at three anatomical sites from 4873 MSM attending Melbourne Sexual Health Centre in 2018 and 2019 to calibrate our models and data from the USA, Netherlands and Thailand for sensitivity analyses.

PARTICIPANTS

Published available data on MSM with multisite infections of gonorrhoea.

PRIMARY AND SECONDARY OUTCOME MEASURES

Incidence of gonorrhoea.

RESULTS

The overall incidence of gonorrhoea was 44 (95% CI 37 to 50)/100 person-years (PY) in scenario 1. Under scenario 2 (20%-80% mouthwash coverage), the total incidence increased (47-60/100 PY) and at all three anatomical sites by between 7.4% (5.9%-60.8%) and 136.6% (108.1%-177.5%). Under scenario 3, with the same coverage, the total incidence decreased (20-39/100 PY) and at all anatomical sites by between 11.6% (10.2%-13.5%) and 99.8% (99.2%-100%). Under scenario 4, changes in the incidence depended on the efficacy of mouthwash on the susceptibility or transmissibility. The effect on the total incidence varied (22-55/100 PY), and at all anatomical sites, there were increases of nearly 130% and large declines of almost 100%.

CONCLUSIONS

The effect of mouthwash on gonorrhoea incidence is largely predictable depending on whether it increases susceptibility to or reduces the transmissibility of gonorrhoea.

Sexual risk-taking among homeless young people in Pakistan

Homeless young people who engage in sex work are at increased risk of HIV and other sexually transmitted infections like chlamydia, gonorrhoea, syphilis and herpes. Semi-structured interviews were conducted with 29 homeless young people between the ages of 16 and 25 years from Rawalpindi, Pakistan, to explore how sexual practices were mediated through social and contextual conditions. Participants engaged in sex for a range of reported reasons, most commonly to generate income, but also to build intimacy and to establish intimate partnerships which could bring physical protection and social and emotional support. Although participants were aware of the sexual health risks attached to condomless sex, they engaged in it due to the social obligations of intimate partnerships, financial considerations and to better manage potentially violent situations. Instead of condoms, participants used alternate methods like withdrawal, oral sex, post-sex douching and specific sexual positions. These were not always useful, and some methods might have inadvertently increased their risk of HIV. The study findings suggest that an integrated health promotion approach that goes beyond the health sector and a singular emphasis on risk awareness may help reduce young people's risk of homelessness and sexual health risks.

Identification of bile acid and fatty acid species as candidate rapidly bactericidal agents for topical treatment of gonorrhoea

BACKGROUND

Novel therapeutic strategies are urgently needed for Neisseria gonorrhoeae, given its increasing antimicrobial resistance. Treatment of oropharyngeal N. gonorrhoeae infections has proven particularly challenging, with most reported treatment failures of the first-line drug ceftriaxone occurring at this site and lower cure rates in recent trials of new antibiotics reported for oropharyngeal infections compared with other sites of infection. However, the accessibility of the oropharynx to topical therapeutics provides an opportunity for intervention. Local delivery of a therapeutic at a high concentration would enable the use of non-traditional antimicrobial candidates, including biological molecules that exploit underlying chemical sensitivities of N. gonorrhoeae but lack the potency or pharmacokinetic profiles required for effective systemic administration.

METHODS

Two classes of molecules that are thought to limit gonococcal viability in vivo, bile acids and short- and medium-chain fatty acids, were examined for rapid bactericidal activity.

RESULTS

The bile acids deoxycholic acid (DCA) and chenodeoxycholic acid (CDCA), but not other bile acid species, exerted extremely rapid bactericidal properties against N. gonorrhoeae, reducing viability more than 100 000-fold after 1 min. The short-chain fatty acids formic acid and hexanoic acid shared this rapid bactericidal activity. All four molecules are effective against a phylogenetically diverse panel of N. gonorrhoeae strains, including clinical isolates with upregulated efflux pumps and resistance alleles to the most widely used classes of existing antimicrobials. DCA and CDCA are both approved therapeutics for non-infectious indications and are well-tolerated by cultured epithelial cells.

CONCLUSIONS

DCA and CDCA are attractive candidates for further development as anti-gonococcal agents.

Octenidine/carbenicillin GUMBOS as potential treatment for oropharyngeal gonorrhoea

BACKGROUND

Reducing Neisseria gonorrhoeae colonies in the oropharynx is a viable solution to minimize the transmission of this bacterium amongst individuals.

OBJECTIVES

A strategy involving the electrostatic interaction between a common antiseptic and a discontinued antibiotic (i.e. octenidine and carbenicillin) was evaluated as a potential treatment for gonorrhoea. Octenidine/carbenicillin is a novel group of uniform materials based on organic salts (GUMBOS) with inherent in vitro antibacterial activity that comes from its parent antiseptic and antibacterial ions, octenidine and carbenicillin, respectively.

METHODS

Antibacterial activities for octenidine dihydrochloride, disodium carbenicillin, octenidine/carbenicillin and stoichiometrically equivalent 1:1 octenidine dihydrochloride to disodium carbenicillin were assessed using the Kirby-Bauer disc diffusion assay for N. gonorrhoeae (ATCC 49226) and three clinical isolates. Predictive permeability using the Parallel Artificial Membrane Permeability Assay and cytotoxicity against HeLa cells was also evaluated.

RESULTS

Additive in vitro antibacterial activities against N. gonorrhoeae were observed in this study, which suggests octenidine/carbenicillin could be a useful agent in reducing N. gonorrhoeae transmission and minimizing gonorrhoea infections. Octenidine/carbenicillin also exhibited bioequivalence to azithromycin and doxycycline, two currently prescribed antibiotics. Likewise, octenidine/carbenicillin had improved predicted permeability compared with octenidine dihydrochloride.

CONCLUSIONS

Antimicrobial GUMBOS synthesized in this study could be used as an adjunctive treatment approach to current drug therapies for oropharyngeal gonorrhoea infection control and prevention.

Current status and future of delivery systems for prevention and treatment of infections in the oral cavity

Oral health reflects the general health, and it is fundamental to well-being and quality of life. An infection in the oral cavity can be associated with serious complications in human health. Local therapy of these infections offers many advantages over systemic drug administration, targeting directly to the diseased area while minimizing systemic side effects. Specialized drug delivery systems into the oral cavity have to be designed in such a fashion that they resist to the aqueous environment that is constantly bathed in saliva and subject to mechanical forces. Additionally, a prolonged release of drug should also be provided, which would enhance the efficacy and also decrease the repeated dosing. This review is aimed to summarize the current most relevant findings related to local drug delivery of various drug groups for prevention and treatment of infections (viral, bacterial, fungal) and infection-related manifestations in the oral cavity. Current therapeutic challenges in regard to effective local drug delivery systems will be discussed, and the recent approaches to overcome these obstacles will be reviewed. Finally, future prospects will be overviewed to promote novel strategies that can be implemented in clinical management for prevention and treatment of oral infections.

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).

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.

Population-Level Antimicrobial Consumption Is Associated With Decreased Antimicrobial Susceptibility in Neisseria gonorrhoeae in 24 European Countries: An Ecological Analysis

OBJECTIVES

There are substantial variations between different populations in the susceptibility of Neisseria gonorrhoeae to antimicrobials, and the reasons for this are largely unexplored. We aimed to assess whether the population-level consumption of antimicrobials is a contributory factor.

METHODS

Using antimicrobial susceptibility data from 24 countries in the European Gonococcal Antimicrobial Surveillance Programme and antimicrobial consumption data from the IQVIA MIDAS database, we built mixed-effects linear/logistic regression models with country-level cephalosporin, fluoroquinolone, and macrolide consumption (standard doses/1000 population/year) as the explanatory variables (from 2009 to 2015) and 1-year-lagged ceftriaxone, cefixime, azithromycin, and ciprofloxacin geometric mean minimum inhibitory concentrations (MICs) as the outcome variables (from 2010 to 2016).

RESULTS

Positive correlations were found between the consumption of cephalosporins and the geometric mean MICs of ceftriaxone and cefixime (P < .05 for both comparisons). Fluoroquinolone consumption was positively associated with the prevalence of resistance to ciprofloxacin (P < .05).

CONCLUSIONS

Differences in the population-level consumption of particular antimicrobials may contribute to variations in the level of antimicrobial resistance in N. gonorrhoeae in different settings. Further interventions to reduce misuse and overuse of antimicrobials in high-consumption populations and core groups are required.

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.

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.

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.

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.

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.

Gonorrhoea

The bacterium Neisseria gonorrhoeae causes the sexually transmitted infection (STI) gonorrhoea, which has an estimated global annual incidence of 86.9 million adults. Gonorrhoea can present as urethritis in men, cervicitis or urethritis in women, and in extragenital sites (pharynx, rectum, conjunctiva and, rarely, systemically) in both sexes. Confirmation of diagnosis requires microscopy of Gram-stained samples, bacterial culture or nucleic acid amplification tests. As no gonococcal vaccine is available, prevention relies on promoting safe sexual behaviours and reducing STI-associated stigma, which hinders timely diagnosis and treatment thereby increasing transmission. Single-dose systemic therapy (usually injectable ceftriaxone plus oral azithromycin) is the recommended first-line treatment. However, a major public health concern globally is that N. gonorrhoeae is evolving high levels of antimicrobial resistance (AMR), which threatens the effectiveness of the available gonorrhoea treatments. Improved global surveillance of the emergence, evolution, fitness, and geographical and temporal spread of AMR in N. gonorrhoeae, and improved understanding of the pharmacokinetics and pharmacodynamics for current and future antimicrobials in the treatment of urogenital and extragenital gonorrhoea, are essential to inform treatment guidelines. Key priorities for gonorrhoea control include strengthening prevention, early diagnosis, and treatment of patients and their partners; decreasing stigma; expanding surveillance of AMR and treatment failures; and promoting responsible antimicrobial use and stewardship. To achieve these goals, the development of rapid and affordable point-of-care diagnostic tests that can simultaneously detect AMR, novel therapeutic antimicrobials and gonococcal vaccine(s) in particular is crucial.

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.

Factors Associated With Pharyngeal Gonorrhea in Young People: Implications for Prevention

BACKGROUND

The objective of this study was to examine the proportion of missed infections and correlates of pharyngeal gonorrhea among young people attending public sexually transmitted disease (STD) clinics.

METHODS

We conducted a case-control study of 245 young men and women between April 2012 and May 2014. Participants were eligible for inclusion if they (1) were 15 to 29 years of age, (2) reported giving oral sex to a partner of the opposite sex in the past 90 days, and (3) attended 1 of 12 public STD clinics in Los Angeles County. Computer-assisted self-interviews were used to collect information on sexual behaviors and tests were conducted for pharyngeal and urogenital gonorrhea.

RESULTS

Most participants were younger than 25 years (69%) and more than half were female (56%). We identified a total of 64 cases (27%) of gonorrhea, of which 29 (45%) were a urogenital only infection, 18 (28%) were a pharyngeal only, and 17 (27%) were dually infected at both sites. Pharyngeal testing increased case finding by 39% from 46 to 64 cases. After adjusting for age, sex, and number of sex partners, those who reported consistent pharyngeal exposure to ejaculate/vaginal fluids were 3 times as likely to have pharyngeal gonorrhea as compared with those without this exposure (adjusted odds ratio, 3.1; 95% confidence interval, 1.3-7.5).

CONCLUSIONS

A large proportion of gonorrhea cases among young people would be missed in the absence of pharyngeal testing. These results have implications for those who provide medical care to clients at STD clinics and highlight the need for pharyngeal screening recommendations and counseling messages related to strategies to reduce exposure to infected fluids.

World Health Organization Global Gonococcal Antimicrobial Surveillance Program (WHO GASP): review of new data and evidence to inform international collaborative actions and research efforts

Antimicrobial resistance (AMR) in Neisseria gonorrhoeae is a serious public health problem, compromising the management and control of gonorrhoea globally. Resistance in N. gonorrhoeae to ceftriaxone, the last option for first-line empirical monotherapy of gonorrhoea, has been reported from many countries globally, and sporadic failures to cure especially pharyngeal gonorrhoea with ceftriaxone monotherapy and dual antimicrobial therapies (ceftriaxone plus azithromycin or doxycycline) have been confirmed in several countries. In 2018, the first gonococcal isolates with ceftriaxone resistance plus high-level azithromycin resistance were identified in England and Australia. The World Health Organization (WHO) Global Gonococcal Antimicrobial Surveillance Program (GASP) is essential to monitor AMR trends, identify emerging AMR and provide evidence for refinements of treatment guidelines and public health policy globally. Herein we describe the WHO GASP data from 67 countries in 2015-16, confirmed gonorrhoea treatment failures with ceftriaxone with or without azithromycin or doxycycline, and international collaborative actions and research efforts essential for the effective management and control of gonorrhoea. In most countries, resistance to ciprofloxacin is exceedingly high, azithromycin resistance is present and decreased susceptibility or resistance to ceftriaxone has emerged. Enhanced global collaborative actions are crucial for the control of gonorrhoea, including improved prevention, early diagnosis, treatment of index patient and partner (including test-of-cure), improved and expanded AMR surveillance (including surveillance of antimicrobial use and treatment failures), increased knowledge of correct antimicrobial use and the pharmacokinetics and pharmacodynamics of antimicrobials and effective drug regulations and prescription policies (including antimicrobial stewardship). Ultimately, rapid, accurate and affordable point-of-care diagnostic tests (ideally also predicting AMR and/or susceptibility), new therapeutic antimicrobials and, the only sustainable solution, gonococcal vaccine(s) are imperative.

The role of saliva in gonorrhoea and chlamydia transmission to extragenital sites among men who have sex with men: new insights into transmission

INTRODUCTION

Gonorrhoea and chlamydia cases have been rising among gay, bisexual and other men who have sex with men (MSM) over the last decade. The majority of cases are extragenital and occur at the oropharynx and anorectum. The aim of this narrative review was to review the risk factors and mode of transmission for gonorrhoea and chlamydia at the oropharynx and anorectum among MSM.

RESULTS AND DISCUSSION

New evidence suggests that oropharyngeal gonorrhoea can be transmitted by kissing in addition to through the established route of condomless oral sex; and anorectal gonorrhoea can be acquired when saliva is used as a lubricant for anal sex and rimming in addition to the established route of condomless penile-anal sex in MSM. In contrast, condomless penile-anal sex remains the major route for chlamydia transmission.

CONCLUSIONS

Substantial transmission of gonorrhoea may occur with practices other than the established routes of condomless oral and/or anal sex and hence condoms may not be effective in preventing gonorrhoea transmission to extragenital sites. In contrast, condoms are effective for chlamydia control because it is mainly transmitted through condomless penile-anal sex. Novel interventions for gonorrhoea that reduce the risk of transmission at extragenital site are required.

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.

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.

Rethinking Risk, Culture, and Intervention in Collective Sex Environments

This article provides a narrative overview of research on HIV/STI risk and collective sexual behavior based on an inclusive analysis of research on environments where people gather for sexual activity-sex clubs, swingers' clubs, bathhouses, parks, private sex parties, etc. The aim is to analyze how collective sex has been approached across disciplines to promote conversation across paradigms and suggest new lines of inquiry. Attention to context-such as the location of sex-was a necessary redress to universalizing models of sexual risk-taking behavior, leading to insights rooted in the particularities of each environment and its users. However, the identification of ever more precise risk groups or environmental idiosyncrasies eventually becomes theoretically restrictive, leading to an overestimation of the uniqueness of sexual enclaves, and of the difference between any given enclave and the broader social milieu. Using a theoretical framework of transgression to interpret the interdisciplinary literature, similarities in the spatial and social organization of collective sex environments are identified. Insights generated from this complementary perspective are then applied to understandings of collective sex: first, the example of male-female (MF) "swingers" is used to illustrate the need to establish, rather than assume, the distinctiveness of each non-normative sexual enclave, and to broaden the conceptualization of context; second, questions are raised about the practicality of interventions in collective sex environments. Finally, new lines of intellectual inquiry are suggested to shed light not just on collective sex but on sociosexual issues more generally, such as increasing protective sexual health behavior or negotiating consent in sexual encounters.

Prevalence of macrolide resistance in Treponema pallidum is associated with macrolide consumption

We hypothesized that the large global variations in the prevalence of macrolide resistance in Treponema pallidum are related to differences in population-level macrolide consumption. The hypothesis was tested by, at a country-level, regressing the peak prevalence of macrolide resistance against the national macrolide consumption in the year prior to this, controlling for the year of the resistance prevalence estimate. A strong association was found between the per capita consumption of macrolides and macrolide resistance (coefficient 0.7, 95 % confidence interval 0.2-0.12, P=0.009).

Self-Reported Use of Mouthwash and Pharyngeal Gonorrhoea Detection by Nucleic Acid Amplification Test

BACKGROUND

Use of alcohol-containing mouthwash has been found to have an inhibitory effect against pharyngeal gonorrhoea. The aim of this study was to investigate the association between self-reported mouthwash use and pharyngeal gonorrhoea detection among men who have sex with men (MSM).

METHODS

A cross-sectional survey was conducted between March 23, 2015, and June 30, 2015 among MSM attending the Melbourne Sexual Health Centre in Australia. Men who have sex with men were invited to complete a short questionnaire on mouthwash use and they were also tested for pharyngeal gonorrhoea by nucleic acid amplification test. Multivariate logistic regression was performed to examine the association between mouthwash use and pharyngeal gonorrhoea detection.

RESULTS

Of the 823 MSM, pharyngeal gonorrhoea detection decreased significantly with increasing age group (≤24 years, 14.5%; 25-34 years, 10.7%; ≥35 years, 6.0%; ptrend = 0.003). The proportion reporting daily use of mouthwash increased significantly with increasing age group (from 10.1% to 14.5% to 19.8%; ptrend = 0.005). However, there was no significant association between pharyngeal gonorrhoea detection and daily use of mouthwash after adjusting for age, number of male sexual partners, human immunodeficiency virus status, and type of mouthwash use.

CONCLUSIONS

Although the proportion of daily use of mouthwash increased with age, and pharyngeal gonorrhoea detection decreased with age, the association between self-reported mouthwash use and pharyngeal gonorrhoea detection by nucleic acid amplification test was not statistically significant.

Neisseria gonorrhoeae Transmission Among Men Who Have Sex With Men: An Anatomical Site-Specific Mathematical Model Evaluating the Potential Preventive Impact of Mouthwash

BACKGROUND

Gonorrhoea notifications are rapidly rising in men who have sex with men (MSM). We developed a model to assess mouthwash as a novel intervention for gonorrhoea control.

METHODS

We developed a model of Neisseria gonorrhoeae (NG) transmission to explain anatomic site-specific prevalence of gonorrhoea among MSM. The model was calibrated to available epidemiological and behavioral data. We estimated the contribution of various sexual acts to gonorrhoea incidence and evaluate the potential impacts of screening scale-up and utilization of mouthwash on the gonorrhoea epidemic.

RESULTS

We calibrated the model to prevalence of oropharyngeal, anal, and urethral gonorrhoea of 8.6% (7.7-9.5%), 8.3% (7.4-9.1%), and 0.20% (0.04-0.35%), respectively, among MSM. Oropharynx to oropharynx transmission through kissing is estimated to account for nearly three quarters of all incident cases (71.6% [64.4-80.5%]) of gonorrhoea in MSM. Substantially increasing annual oropharynx screening for gonorrhoea from the current 40% to 100% may only halve the prevalence of gonorrhoea in MSM. In contrast, the use of mouthwash with moderate efficacy (additional 1% clearance per daily use) would further reduce the corresponding prevalence rates to 3.1% (2.2-4.4%), 3.8% (2.3-4.9%), and 0.10% (0.06-0.11%), and a high-efficacy mouthwash (additional 1.5% clearance per daily use) may further halve the gonorrhoea prevalence. Without oropharynx to oropharynx transmission, we could not replicate current prevalence data.

CONCLUSIONS

Despite a dearth of empirical data, our model suggests that kissing could potentially play an important role in NG transmission among MSM. Control through sexually transmitted infection screening alone is unlikely to have a substantial impact on the gonorrhoea epidemic in MSM.