Models of gonorrhoea transmission from the mouth and saliva

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.

Neisseria gonorrhoeae vaccines: a contemporary overview

Neisseria gonorrhoeae infection is an important public health issue, with an annual global incidence of 87 million. N. gonorrhoeae infection causes significant morbidity and can have serious long-term impacts on reproductive and neonatal health and may rarely cause life-threatening disease. Global rates of N. gonorrhoeae infection have increased over the past 20 years. Importantly, rates of antimicrobial resistance to key antimicrobials also continue to increase, with the United States Centers for Disease Control and Prevention identifying drug-resistant N. gonorrhoeae as an urgent threat to public health. This review summarizes the current evidence for N. gonorrhoeae vaccines, including historical clinical trials, key N. gonorrhoeae vaccine preclinical studies, and studies of the impact of Neisseria meningitidis vaccines on N. gonorrhoeae infection. A comprehensive survey of potential vaccine antigens, including those identified through traditional vaccine immunogenicity approaches, as well as those identified using more contemporary reverse vaccinology approaches, are also described. Finally, the potential epidemiological impacts of a N. gonorrhoeae vaccine and research priorities for further vaccine development are described.

STI pathogens in the oropharynx: update on screening and treatment

PURPOSE OF REVIEW

The rise in antimicrobial resistance in several STI pathogens such as Neisseria gonorrhoeae has become a public health threat as only one first-line treatment remains. Reducing screening interval for gonorrhoea and chlamydia in high-prevalence populations has been proposed to address antimicrobial stewardship, but this remains controversial. This review aimed to revisit the epidemiology of infections at the oropharynx and review the current screening recommendations and treatment guidelines in different populations.

RECENT FINDINGS

Emerging evidence suggests that the oropharynx is the primary anatomical site for gonorrhoea transmission but maybe not for chlamydia transmission. Most international guidelines recommend 3-monthly oropharyngeal gonorrhoea and chlamydia screening for high-prevalence populations (e.g. men who have sex with men) but not low-prevalence populations (e.g. heterosexuals) given the clinical and public health benefits of screening in low-prevalence populations are still unclear. Doxycycline remains the first-line treatment for oropharyngeal chlamydia in most guidelines. However, some countries have moved from dual therapy (ceftriaxone and azithromycin) to monotherapy (ceftriaxone) for oropharyngeal gonorrhoea treatment to address antimicrobial stewardship.

SUMMARY

The transmission of gonorrhoea and chlamydia is still not fully understood. Further work will be required to evaluate the benefits and harms of reducing screening in high-prevalence populations.

Inadequate performance of a risk score to predict asymptomatic Neisseria gonorrhoeae and Chlamydia trachomatis infection among cisgender men who have sex with men

OBJECTIVES

Epidemiological treatment of persons who are sexual contacts to partners with Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) often results in treatment of uninfected persons, which may increase the risk of antibiotic-resistant infections. We sought to identify the predictors of NG and/or CT infections to develop a risk score that could be used to limit epidemiological treatment to persons most likely to have these infections.

METHODS

We included visits to the Public Health - Seattle & King County Sexual Health Clinic by asymptomatic cisgender men who have sex with men (MSM) aged ≥18 who presented as a sexual contact to partner(s) with CT or NG infection between 2011 and 2019. We used logistic regression to estimate the odds of CT and/or NG infections associated with demographic and clinical predictors, selecting the final set of predictors using the Akaike information criteria and obtaining score weights from model coefficients. We used a cross-validation approach to obtain average model discrimination from each of 10 models, leaving out 10% of the data, and evaluated sensitivity and specificity at various score cut-offs.

RESULTS

The final model for predicting NG or CT infection included seven predictors (age <35 years, HIV status, receptive oral sex in the prior 2 months, CT diagnosis, condomless receptive anal intercourse, condomless insertive anal intercourse and methamphetamine use in the prior 12 months). Model discrimination, as measured by the receiver operating curve, was 0.60 (95% CI 0.54 to 0.66). Sensitivity for detection of infection was ≥90% for scores ≥3, ≥5 and ≥7; specificity for these cut-offs was <16%. At scores ≥9, ≥12 and ≥14, specificity increased but sensitivity decreased to ≤76%.

CONCLUSIONS

Our risk score did not sufficiently discriminate between asymptomatic MSM with and without NG/CT infection. Additional studies evaluating epidemiological treatment as a standard of care in diverse populations are needed to guide best practices in the management of contacts to NG/CT infection.

A Systematic Review of Kissing as a Risk Factor for Oropharyngeal Gonorrhea or Chlamydia

BACKGROUND

Tongue kissing is a poorly studied risk factor for sexually transmitted infections (STIs). We undertook the first systematic review to assess whether kissing is a risk factor for gonorrhea or chlamydia of the oropharynx.

METHODS

Online databases (MEDLINE, EMBASE, CINAHL, Web of Science, Cochrane) and reference lists were searched until September 30, 2022. The eligibility criteria for studies included: any peer-reviewed study design in the English language; gonorrhea or chlamydia diagnosed by nucleic acid amplification test, or an infection self-reported by a patient; tongue kissing or its equivalent measured as an exposure. Studies were appraised using a quality scoring tool and qualitatively synthesized.

RESULTS

Of 8248 studies screened, 6 were eligible for review. All were conducted among men who have sex with men in Australia, including 3 prospective cohort studies, 2 cross-sectional studies, and 1 age-matched case-control study. In summary, all 5 studies examining gonorrhea found an unadjusted association between kissing and oropharyngeal gonorrhea. Two cross-sectional studies found that tongue kissing was an independent risk factor for oropharyngeal gonorrhea after adjusting for other confounders, such as participant demographic characteristics and other sexual practices. In contrast, a single eligible prospective cohort study found no association between kissing and oropharyngeal chlamydia.

CONCLUSIONS

This systematic review summarized the existing evidence that suggests that tongue kissing may be a risk factor for oropharyngeal gonorrhea but not chlamydia. Reinforcing the message that oropharyngeal gonorrhea could be transmitted through kissing may inform the development of novel approaches to prevent and treat gonorrhea.

Sexually transmitted infections and sexual behaviour among men having sex with men from Tshwane, South Africa

BACKGROUND

Men having sex with men (MSM) are at increased risk of acquiring sexually transmitted infections (STIs), including extra-urethral infections. This study aimed to provide information on the presence of genital and extra-genital non-viral STIs and associated risk factors among MSM in the Tshwane district of South Africa.

METHOD

Samples were collected from 200 MSM in the North-western area of Tshwane. After the completion of a questionnaire including demographics and sexual history and an HIV test, three swabs (pharyngeal, rectal, and urethral) were collected and tested for the presence of Neisseria gonorrhoeae (NG), Chlamydia trachomatis (CT), Mycoplasma genitalium (MG) and Trichomonas vaginalis (TV).

RESULTS

Data were collected from 199 participants and 77/199 (38.7%) participants had at least one infection regardless of specimen site. Of these 34 (17.1%) were infected with NG; 36 (18.1%) with CT, 16 (8.1%) with MG and 14 (7.0%) with TV. NG and CT were most frequently detected in rectal specimens. The HIV prevalence in this study was 66.8% (133/199), with 56 (28.1%) of participants both STI and HIV positive. Being between 18 and 20 years, and difficulty having safe sex (more sex partners and more often condomless anal sex) when high/drunk were significantly associated with having an STI. Factors with increased odds of having an STI were being HIV positive, having two or more sexual partners, depending on partner financially, performing and receiving rimming, or receiving anal sex.

CONCLUSIONS

This study has highlighted the high burden of STIs in MSM in the local community, especially the prevalence of these pathogens in extra-genital sites.

Sexual activities and condom use among heterosexual men and women engaged in mixed-gender group sex events in Melbourne, Australia

BACKGROUND

Few studies investigate group sex among heterosexuals. The aim of this study was to provide an exploration of characteristics and practices among heterosexual men and women who engage in group sex.

METHOD

We conducted a cross-sectional survey between May 2019 and March 2020 among heterosexual men and women attending a sexual health clinic in Melbourne, Australia. Participants were asked whether they had participated in group sex (sex involving more than two participants) in the past 3months, the size of the most recent event, sexual activities in which they engaged, and condom use.

RESULTS

Of 3277 heterosexuals surveyed (1509 women and 1768 men), the mean age was 29.9years (s.d. 8.8) and more than half (56.0%, n =1834) were born outside Australia. One in 20 participants (5.4%) had engaged in group sex in the past 3months with the number of events ranging 1-10times. Kissing was the most common activity in group sex, and women were significantly more likely to kiss a same-sex partner than men. Overall, of 165 participants who engaged in vaginal sex, 57 (34.5%) reported always using condoms and changing condoms between consecutive partners. Of the 100 men and women who had condomless vaginal sex, 79 (79.0%) received or performed fellatio after condomless vaginal sex.

CONCLUSION

About two-thirds of heterosexuals who engaged in group sex neither used condoms nor changed condoms between partners in the most recent group sex event. Safe sex messages on changing condoms between partners and between sexual activities should be reinforced for sexually transmitted infections prevention.

Frequency and Combination of Sequential Sexual Acts That May Lead to Sexually Transmitted Infections at Different Anatomic Sites Within the Same Person

Modeling studies suggest that transmission of gonorrhea and chlamydia to multiple anatomic sites within the same person is necessary to reproduce observed high rates of extragenital gonorrhea/chlamydia. Limited empiric behavioral data support this idea. In this cross-sectional study, we enrolled individuals assigned male at birth who reported sex with men (MSM) and denied receptive anal sex (RAS) in the past 2 years. Participants enrolled in-person at the Sexual Health Clinic in Seattle, Washington (December 2019-September 2021) or online (July 2021-September 2021), and completed a sexual history questionnaire that asked about specific sexual acts and sequence of those acts during their last sexual encounter. We enrolled 210 MSM during the 16-month recruiting period. The median number of sex acts reported at last sexual encounter was 4 (interquartile range 3-5). The most commonly reported acts at last sex were: kissing (83%), receiving oral sex (82%), and insertive anal sex (65%). There was substantial variability in the sequence of acts reported; no unique sequence of sex acts was reported by more than 12% of the population. Ninety percent of participants reported sequences of behaviors that could lead to gonorrhea or chlamydia transmission within the same person (respondent or partner); the most common of these combinations was kissing followed by receiving oral sex (64% reporting). Engaging in multiple sex acts within a single sexual encounter is common and may lead to gonorrhea/chlamydia transmission within the same person. This complicates empiric measurements of transmission probabilities needed to estimate population-level transmission.

The duration and body position during tongue-kissing among heterosexual men and women

Background

Emerging data suggest tongue-kissing may transmit gonorrhea. We aim to examine the duration or body position of heterosexual men and women during tongue-kissing (henceforth, known as kissing).

Methods

A cross-sectional survey among heterosexual men and women attending the Melbourne Sexual Health Centre in Australia between May 2019 and March 2020 collected data on the duration and body position (i.e., on top of or lying down underneath) of their most recent kissing partner in the past 3 months. Univariable and multivariable linear regressions were performed to examine the association between gender and kissing duration.

Results

Of 2,866 individuals, 93.6% (n = 2,683) had at least one kissing partner in the past 3 months, which included 1,342 (50.1%) men and 1,341 (49.9%) women, and 87.2% (n = 2,339) had sex with their opposite-gender kissing partner. The adjusted mean duration of kissing with the most recent opposite-gender kissing partner did not differ between men and women (12.2 vs. 11.5 min, p = 0.170). More men were on top of their most recent opposite-gender kissing partner compared to women (87.9 vs. 82.9%, p < 0.001). Men reported a longer kissing duration than women when they were on top of the opposite-gender kissing partner (8.3 vs. 7.4 min, p = 0.006). More women had same-gender kissing partners than men (9.6 vs. 2.8%, p < 0.001).

Conclusion

Men spending longer than women on top of their opposite-gender kissing partner suggests a potential alternative explanation for oropharyngeal gonorrhea being seen more commonly in women. Further research should investigate whether body positioning and duration of kissing influence the risk of gonorrhea transmission.

Optimisation of treatments for oral Neisseria gonorrhoeae infection: Pharmacokinetics Study (STI-PK project) - study protocol for non-randomised clinical trial

INTRODUCTION

Neisseria gonorrhoeae infections are common and incidence increasing. Oropharyngeal infections are associated with greater treatment failure compared with other sites and drive transmission to anogenital sites through saliva. Gonococcal resistance is increasing and new treatments are scarce, therefore, clinicians must optimise currently available and emerging treatments in order to have efficacious therapeutic options. This requires pharmacokinetic data from the oral cavity/oropharynx, however, availability of such information is currently limited.

METHODS AND ANALYSIS

Healthy male volunteers (participants) recruited into the study will receive single doses of either ceftriaxone 1 g, cefixime 400 mg or ceftriaxone 500 mg plus 2 g azithromycin. Participants will provide samples at 6-8 time points (treatment regimen dependent) from four oral sites, two oral fluids, one anorectal swab and blood. Participants will complete online questionnaires about their medical history, sexual practices and any side effects experienced up to days 5-7. Saliva/oral mucosal pH and oral microbiome analysis will be undertaken. Bioanalysis will be conducted by liquid chromatography-mass spectrometry. Drug concentrations over time will be used to develop mathematical models for optimisation of drug dosing regimens and to estimate pharmacodynamic targets of efficacy.

ETHICS AND DISSEMINATION

This study was approved by Royal Melbourne Hospital Human Research Ethics Committee (60370/MH-2021). The study results will be submitted for publication in peer-reviewed journals and reported at conferences. Summary results will be sent to participants requesting them. All data relevant to the study will be included in the article or uploaded as supplementary information.

TRIAL REGISTRATION NUMBER

ACTRN12621000339853.

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.

Kissing, fellatio, and analingus as risk factors for oropharyngeal gonorrhoea in men who have sex with men: A cross-sectional study

BACKGROUND

Our aim was to determine whether exposure to the anatomical sites (oropharynx, penis, or anus) of male partners of men who have sex with men (MSM) were independent risk factors for oropharyngeal gonorrhoea after adjusting for exposures to these sites.

METHODS

In this cross-sectional study, we invited MSM who attended the Melbourne Sexual Health Centre (MSHC) in Victoria, Australia between 26-November 2018 and 31-December 2020 to complete a survey of their sexual practices in the past three months. We collected data on the number of male partners with whom men engaged in sexual activities that exposed their oropharynx to their partners' oropharynx (kissing), penis (fellatio), and anus (rimming or analingus). Only men who were aged ≥16 years, tested for oropharyngeal gonorrhoea and did not have indeterminate or invalid results were included in the final analysis. We conducted univariable and multivariable logistic regression analyses to investigate associations between oropharyngeal gonorrhoea and the three exposures to the oropharynx.

FINDINGS

The median age of the 2,322 men who completed the survey was 31 years (IQR: 26-40), and 5·2% (n = 120) were diagnosed with oropharyngeal gonorrhoea. Our univariate analysis showed that oropharyngeal gonorrhoea was significantly associated with increasing number of kissing (p _trend<0·0001), rimming (p _trend<0·0001) and fellatio (p _trend<0·0001) partners. After adjusting for all three exposures, oropharyngeal gonorrhoea was associated with increasing number of kissing (p _{trend =}0·014) and rimming partners (p _trend = 0·037) but not fellatio (p _trend = 0·61).

INTERPRETATION

Our data suggest kissing and rimming are important practices in oropharyngeal gonorrhoea transmission in MSM Novel interventions which target the oropharynx are required for gonorrohoea prevention.

FUNDING

Australian National Health and Medical Research Council.

Anatomic site-specific gonorrhea and chlamydia testing and incidence among people with HIV engaged in care at four United States clinical centers, 2014-2018

Background

The incidence of Neisseria gonorrhoeae (GC) and Chlamydia trachomatis (CT) is increasing in the United States; however, there are limited data on anatomic site-specific GC/CT among people with HIV (PWH).

Methods

We reviewed records of all PWH in care between January 1, 2014 and November 16, 2018 at four sites in the CFAR Network of Integrated Clinical Systems Cohort (CNICS; N = 8455). We calculated anatomic site-specific GC/CT testing and incidence rates and used Cox proportional hazards models modified for recurrent events to examine sociodemographic and clinical predictors of GC/CT testing and incidence at urogenital, rectal, and pharyngeal sites. We also calculated site-specific number needed to test (NNT) to detect a positive GC/CT test.

Results

Of 8455 PWH, 2460 (29.1%) had at least yearly GC/CT testing at any anatomic site. The rates of urogenital, rectal, and pharyngeal GC were 1.7 (95%CI:1.6, 1.9), 3.2 (95%CI:3.0, 3.5), and 2.7 (95%CI:2.5, 2.9) infections per 100 person-years, respectively. The rates of urogenital, rectal, and pharyngeal CT were 1.9 (95%CI:1.7, 2.1), 4.3 (95%CI:4.0, 4.5), and 0.9 (95%CI:0.8, 1.0) infections per 100 person-years, respectively. PWH 16-39 years old experienced greater GC/CT rates at all anatomic sites while MSM experienced greater rates of extragenital infections. NNTs for urogenital, rectal, and pharyngeal GC/CT were 20 (95%CI:19, 21), 5 (95%CI:5, 5), and 9 (95%CI:8, 9), respectively.

Conclusion

Many PWH are not tested annually for GC/CT and rates of GC/CT infection, particularly rates of extragenital infections, are high. We identified groups of PWH who may benefit from increased site-specific GC/CT testing.

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.

Time to Clearance of Neisseria gonorrhoeae RNA at the Pharynx following Treatment

The number of days until pharyngeal Neisseria gonorrhoeae nucleic acid amplification test (NAAT) results become negative after treatment remains unknown. Between March 2019 and April 2021, we enrolled men who have sex with men (MSM) who had a clinical positive pharyngeal N. gonorrhoeae Aptima Combo 2 test result but had not yet been treated in a prospective longitudinal cohort study. MSM were enrolled on their day of treatment and self-collected daily pharyngeal specimens for 21 days at home. We used Kaplan-Meier estimates to determine the median time to clearance and the >95% time to clearance and the log rank test for equality to evaluate factors associated with time to clearance. Sixty-four men were enrolled in the study. Analyses excluded 8 men (12.5%) who were N. gonorrhoeae negative by NAAT at enrollment and 11 (17%) who failed to return any home-collected specimens. Among the 45 men included in the analysis, the median time to N. gonorrhoeae NAAT clearance was 3 days (95% confidence interval [CI], 2 to 5 days). Time to clearance for >95% of the cohort was 12 days (95% CI, 10 days to an undefined time). Men with a history of N. gonorrhoeae infection cleared faster than men without such history (8 days versus 17 days for >95% time to clearance; P = 0.03). In the absence of reexposure, positive N. gonorrhoeae Aptima Combo 2 assay results obtained prior to 12 days after treatment are likely false-positive results.

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.

Modelling the potential role of saliva use during masturbation in the transmission of Neisseria gonorrhoeae at multiple anatomical sites

Background Neisseria gonorrhoeae can be cultured from saliva in men with pharyngeal gonorrhoea and could theoretically be transmitted from the pharynx to the urethra when saliva is used as a lubricant for masturbation. In this work, we proposed that saliva use during masturbation may be a potential transmission route of gonorrhoea. Methods We analysed the transmission of Neisseria gonorrhoeae at the oropharynx, urethra and anorectum with mathematical models among men who have sex with men using data from six different studies. Model 1 included transmission routes (oral sex, anal sex, rimming, kissing, and three sequential sex practices). In Model 2, we added saliva use during solo masturbation and mutual masturbation to model 1. Results Model 2 could replicate single site infection at the oropharynx, urethra and anorectum and multi-site infection across six different datasets. However, the calibration of Model 2 was not significantly different from Model 1 across four datasets. Model 2 generated an incidence of gonorrhoea from masturbation of between 5.2% (95% CI: 3.2-10.1) to 10.6% (95% CI: 5.8-17.3) across six data sets. Model 2 also estimated that about one in four cases of urethral gonorrhoea might arise from solo masturbation and mutual masturbation. Conclusions Our models raise the possibility that saliva use during masturbation may play a role in transmitting gonorrhoea. This is an important area to explore because it contributes to the knowledge base about gonorrhoea transmission.

Community-Based Prevalence Estimates of Chlamydia trachomatis and Neisseria gonorrhoeae Infections Among Gay, Bisexual, and Other Men Who Have Sex With Men in Montréal, Canada

BACKGROUND

Reported cases of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections are increasing among Canadian men. Estimates of community-based CT/NG prevalence are lacking among gay, bisexual, and other men who have sex with men (GBM).

METHODS

Respondent driven sampling was used to recruit GBM in Montréal, Canada between February 2017 and June 2018. Specimens provided from urogenital, rectal, and pharyngeal sites were analyzed using nucleic acid amplification test to detect CT/NG. Prevalence estimates of CT/NG, overall and by anatomical site were calculated. All estimates are respondent-driven sampling-adjusted.

RESULTS

Among 1177 GBM, the prevalence of rectal, urogenital, pharyngeal and overall were respectively 2.4%, 0.4%, 0.4%, and 2.8% for CT infections, and 3.1%, 0.4%, 3.5%, and 5.6% for NG infections. If testing had been limited to the urogenital site, 80% and 94% of CT and NG infections, respectively, would have been missed.

CONCLUSIONS

This community-based study among GBM shows that the CT prevalence was about half of that observed for NG. A large part of CT/NG infections involves only the extragenital sites, highlighting the need for systematic multisite screening regardless of symptoms. In the mist of the COVID-19 pandemic and the limited CT/NG screening capacity due to test kits shortage, it might be considered to prioritize rectal and pharyngeal CT/NG testing over urogenital testing in asymptomatic GBM.

Oral, Vaginal and Anal Sexual Practices among Heterosexual Males and Females Attending a Sexual Health Clinic: A Cross-Sectional Survey in Melbourne, Australia

Sex practices among heterosexuals are not well studied. We aimed to explore sexual practices among heterosexuals attending a sexual health clinic. This cross-sectional survey was conducted at Melbourne Sexual Health Centre between March and April 2019. Data were collected on kissing, oral sex (fellatio or cunnilingus), vaginal sex, anal sex and rimming in the previous 3 months. Univariable and multivariable logistic regression analyses were performed to examine the associations between engaging in anal sex and other sex practices. There were 709 participants (333 men; 376 women) who were eligible and completed the survey (response rate was 24.6%). In the past 3 months, most participants had had vaginal sex (n = 677; 95.5%), with a mean of 3.0 (standard deviation (SD): 3.9) vaginal sex partners, and half reported engaging in condomless vaginal sex in the past 3 months (n = 358; 50.1%). A total of 135 (19.0%) participants had had anal sex, with a mean of 1.3 (SD: 1.0) anal sex partners, with 63.5% (n = 94) engaging in any condomless anal sex in the past 3 months. Most participants (n = 637, 89.8%) had received oral sex in the past 3 months; this proportion did not differ by age group or gender. Women (n = 351, 93.4%) were more likely to perform oral sex than men (n = 275; 82.6% men) (p < 0.001) and to have received rimming (26.6% women vs. 12.6% men; p < 0.001). Men were more likely to have performed rimming (25.5% men vs. 9.3% women; p < 0.001). After adjusting for age, number of partners and sexual practice, anal sex was associated with being ≥35 years (adjusted odds ratio (aOR): 2.3; 95% CI: 1.2–4.2), receiving rimming (aOR: 3.8; 95% CI: 2.4–6.0) and performing rimming (aOR: 2.8; 95% CI: 1.8–4.6). Rimming and anal sex are practiced by one-fifth or more of heterosexuals. Older heterosexuals were more likely to engage in anal sex and to perform rimming. Future research should consider the benefits of testing extragenital sites where appropriate.

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.

Modelling response strategies for controlling gonorrhoea outbreaks in men who have sex with men in Australia

The ability to treat gonorrhoea with current first-line drugs is threatened by the global spread of extensively drug resistant (XDR) Neisseria gonorrhoeae (NG) strains. In Australia, urban transmission is high among men who have sex with men (MSM) and importation of an XDR NG strain in this population could result in an epidemic that would be difficult and costly to control. An individual-based, anatomical site-specific mathematical model of NG transmission among Australian MSM was developed and used to evaluate the potential for elimination of an imported NG strain under a range of case-based and population-based test-and-treat strategies. When initiated upon detection of the imported strain, these strategies enhance the probability of elimination and reduce the outbreak size compared with current practice (current testing levels and no contact tracing). The most effective strategies combine testing targeted at regular and casual partners with increased rates of population testing. However, even with the most effective strategies, outbreaks can persist for up to 2 years post-detection. Our simulations suggest that local elimination of imported NG strains can be achieved with high probability using combined case-based and population-based test-and-treat strategies. These strategies may be an effective means of preserving current treatments in the event of wider XDR NG emergence.

In most high-income settings, gonorrhoea is endemic among men who have sex with men (MSM). While gonorrhoea remains readily treatable with antibiotics, there are major concerns about the threat of antimicrobial resistance arising from recent reports of treatment failure with first-line therapy and limited remaining treatment options. Here we investigated the potential for test-and-treat response strategies to eliminate such strains before their prevalence reaches a level requiring a shift to new first line therapies. Rather than directly consider resistance, we explore the mitigating effect of various test-and-treat measures on outbreaks of a generic imported strain which remains treatable. This is done within the framework of a realistic mathematical model of gonorrhoea spread in an MSM community that captures cases, anatomical sites of infection and sexual contacts at an individual level, calibrated to relevant Australian epidemiological data. The results indicate that strategies such as partner testing and treatment in combination with elevated asymptomatic community testing are highly effective in mitigating outbreaks but can take up to 2 years to achieve elimination. As there are currently no clear alternative drugs of proven efficacy and safety to replace ceftriaxone in first-line therapy, these promising results suggest potential for use of these outbreak response strategies to preserve current treatment recommendations.

The Performance of Pooled 3 Anatomic Site Testing for Chlamydia trachomatis and Neisseria gonorrhoeae Among Men Who Have Sex With Men and Transgender Women

BACKGROUND

Although molecular testing for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) is highly sensitive, the cost can be prohibitive. Those high costs are amplified when the recommended screening approach is used, which requires separate testing of specimens from 3 anatomic sites (rectal, pharyngeal and urogenital). Although individual molecular testing is standard of care, pooled testing may offer a cost-saving alternative.

METHODS

Using the Xpert® CT/NG assay (Cepheid, Sunnyvale, CA) we tested urine, rectal and pharyngeal swabs for CT and NG in a high-risk cohort of participants assigned male at birth who reported sex with other persons who were assigned male at birth. Remnant specimens (0.34 mL from each anatomic site) were combined to perform a single 'pooled' test. We calculated positive and negative percent agreement between the pooled testing results with standard of care Xpert CT/NG test results as the reference.

RESULTS

We conducted 644 pooled tests. Of those, 598 (92.3%) gave CT and NG results. The CT-positive and -negative percent agreement were 90.1% (95% confidence interval [CI], 80.7-95.9%) and 99.2% (98.1-99.8%), respectively. The NG-positive and -negative percent agreement were 96.2% (95% CI, 86.8-99.5%) and 99.8% (95% CI, 99.0-100%), respectively. Pooled testing identified 4 CT and 1 NG infections that were negative at all anatomic sites by individual testing.

CONCLUSIONS

Three-site pooled CT and NG testing performs similarly to single anatomic site testing among tests providing a valid result. Future cost analyses should evaluate the cost effectiveness of pooled 3-site testing to determine if such a strategy improves the feasibility and accessibility of molecular sexually transmitted infection testing.

Age pattern of sexual activities with the most recent partner among men who have sex with men in Melbourne, Australia: a cross-sectional study

BACKGROUND

Sexual behavioural studies among men who have sex with men (MSM) are predominantly focused on penile-anal intercourse. Other non-anal sexual activities are under-studied. This study aimed to examine the age pattern of a range of sexual activities among MSM with the most recent male sex partner.

METHODS

We conducted a survey among MSM attending the Melbourne Sexual Health Centre in 2017. This survey asked about nine different sexual activities with their most recent regular and casual partner. A Chi-square trend test was used to examine the age patterns of each sexual activity.

RESULTS

A total of 1596 men answered the survey and their median age was 30 (IQR 25-37) years. With casual partners, kissing was the most common activity (92.4%), followed by performing penile-oral sex (86.0%) and receiving penile-oral sex (83.9%). The least common activity was insertive rimming (38.1%). Young men were more likely to engage in kissing (p_trend<0.001), receptive rimming (p_trend=0.004) and receptive penile-anal sex (p_trend<0.001) but they were less likely to have insertive penile-anal sex compared with older MSM. With regular partners, the most common activity was kissing (97.4%), followed by touching penises (90.0%) and performing penile-oral sex (88.3%). Age was not associated with most types of sexual activity with regular partners except mutual masturbation and receptive penile-anal sex. Younger men were more likely to masturbate mutually (p_trend=0.028) and engage in receptive penile-anal sex (p_trend=0.011).

CONCLUSIONS

The pattern of sexual activities shows age-related differences with casual partners but less so with regular partners in MSM.

Treatment efficacy for pharyngeal Neisseria gonorrhoeae: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Rising gonorrhoea rates require highly effective treatments to reduce transmission and prevent development of antimicrobial resistance. Currently the most effective treatments for pharyngeal gonorrhoea remain unclear. This review aimed to estimate treatment efficacy for pharyngeal gonorrhoea.

METHODS

Online bibliographic databases were searched for the period 1 January 2000 to 17 September 2019 for treatments of gonorrhoea. All randomized controlled trials (RCTs) with data on pharyngeal gonorrhoea among participants aged 15 years or above, published in English, were included. Meta-analyses (random effects) were used to estimate the treatment efficacy, defined as microbiological cure, among currently recommended monotherapies and dual therapies, previously recommended but no longer used regimens and emerging drugs under evaluation. Side effects were also summarized. The study protocol was registered on PROSPERO (CRD42020149278).

RESULTS

There were nine studies that included 452 participants studying 19 treatment regimens. The overall treatment efficacy for pharyngeal gonorrhoea was 98.1% (95% CI: 93.8%-100%; I2 = 57.3%; P < 0.01). Efficacy was similar for single (97.1%; 95% CI: 90.8%-100.0%; I2 = 15.6%; P = 0.29) and dual therapies (98.0%; 95% CI: 91.4%-100%; I2 = 79.1%; P < 0.01). Regimens containing azithromycin 2 g or ceftriaxone were similarly efficacious. The summary efficacy estimate for emerging drugs was 88.8% (95% CI: 76.9%-97.5%; I2 = 11.2%; P = 0.34). Small sample sizes in each trial was a major limitation.

CONCLUSIONS

Regimens containing ceftriaxone or azithromycin 2 g, alone or as part of dual therapies are the most efficacious for pharyngeal gonorrhoea. Further pharyngeal-specific RCTs with adequate sample sizes are needed.

Modelling the multiple anatomical site transmission of Mycoplasma genitalium among men who have sex with men in Australia

Mycoplasma genitalium (M. genitalium) is a recently recognised and important sexually transmitted infection among men who have sex with men (MSM). The role of oral sex, rimming, and kissing on M. genitalium transmission in MSM is unclear. We created four deterministic susceptible-infectious-susceptible epidemic models to examine the role that different sexual behaviours play in transmitting M. genitalium at the oropharynx, urethra anorectum among men who have sex with men in Australia. Our results suggest that oral and anal sex without other sexual practices (model 1) replicate well single site infection at the oropharynx, urethra and anorectum and also multi-site infection. If kissing or rimming are added to model 1 (i.e., model 2–4) no substantial improvements in the calibration of the models occur. Model 1 estimates that 3.4% of infections occur at the oropharynx, 34.8% at the urethra and 61.8% at the anorectum. Model 1 also estimates that the proportion of incident M. genitalium transmitted by anal sex was 82.4%, and by oral sex was about 17.6%. Our findings could provide an enhanced understanding of M. genitalium transmission in MSM, thus providing insights into what sexual practices contribute most to transmission.

Oropharyngeal gonorrhoea infections among heterosexual women and heterosexual men with urogenital gonorrhoea attending a sexual health clinic in Melbourne, Australia

OBJECTIVES

There is limited evidence about the transmission and prevalence of oropharyngeal gonorrhoea in heterosexuals. From August 2017, Melbourne Sexual Health Centre (MSHC) began testing for oropharyngeal gonorrhoea among heterosexuals with untreated urogenital gonorrhoea. This study aims to determine the positivity of oropharyngeal gonorrhoea among heterosexuals diagnosed with urogenital gonorrhoea at MSHC between August 2017 and May 2020.

METHODS

We included individuals who had oropharyngeal gonorrhoea testing within 30 days of initial testing. We reported the number and proportion of oropharyngeal gonorrhoea positivity, stratified by gender and contact of gonorrhoea. The χ² test was performed to compare the oropharyngeal gonorrhoea positivity between groups.

RESULTS

Of 617 individuals with untreated urogenital gonorrhoea, 424 (68.7%) were tested for oropharyngeal gonorrhoea. Oropharyngeal gonorrhoea positivity was 38.9% (95%CI 34.2-43.7%, 165/424), and was higher in women than in men (115/252, 45.6% versus 50/172, 29.1%, p = 0.001). Furthermore, oropharyngeal gonorrhoea positivity was higher among individuals who were contacts of gonorrhoea cases compared to those who were not (29/44, 65.9% versus 136/380, 35.8%, p < 0.001). There was also no significant difference between women who were sex workers and those who were not (30/78, 38.5% versus 85/174, 48.9%, p = 0.126).

CONCLUSIONS

Our data suggest that oropharyngeal gonorrhoea infection is common among heterosexual women and heterosexual men with untreated urogenital gonorrhoea. Testing heterosexual women and heterosexual men for oropharyngeal gonorrhoea will identify a significant proportion with unrecognized oropharyngeal infections whose recommended treatment is different in some countries.

Changing Epidemiology of Gonorrhea in Adelaide, South Australia

BACKGROUND

Gonorrhea is a significant public health concern. The changing epidemiology of gonorrhea in Australia has highlighted the need for detailed examination of surveillance data to determine population groups at greatest risk for infection.

METHODS

We analyzed deidentified gonorrhea notification data for the years 2012 to 2017, in Adelaide (N = 3680), calculating age-adjusted notification and antibiotic resistance rates. Age, gender, year, sexual orientation, and socioeconomic status were assessed for associations with gonorrhea notifications using negative binomial, log binomial and spatial autoregressive models. Maps were generated to examine spatial localization of gonorrhea rates in Adelaide.

RESULTS

Gonorrhea notification rates in Adelaide increased annually, with a 153% adjusted increase in rates from 2012 to 2017, localized to specific areas and inversely associated with income levels. The increase in rates in 2016 and 2017 was associated with young heterosexuals from low income areas. Azithromycin-resistant notifications increased significantly in 2016 in young heterosexuals. Reinfections were significantly more likely in men who have sex with men than other population groups.

CONCLUSIONS

This study demonstrates the changing epidemiology of gonorrhea in Adelaide from a largely men who have sex with men profile toward an increase in young heterosexual gonorrhea. This could be seen as a harbinger for future increases in heterosexually transmitted HIV and other sexually transmitted infections in Australia.

Factors Associated With Early Resumption of Condomless Anal Sex Among Men Who Have Sex With Men After Rectal Chlamydia Treatment

BACKGROUND

The resumption of sexual activity shortly after commencing treatment for sexually transmitted infections (STIs) is poorly described despite contributing to onward transmission. With azithromycin remaining an option for rectal Chlamydia trachomatis, resuming sex too early after treatment may contribute to antimicrobial resistance because of exposure of newly acquired STIs to subinhibitory concentrations.

METHODS

Clinical and sexual behavioral data were collected from men participating in a trial assessing treatment efficacy for rectal chlamydia. Data were collected at recruitment and weekly for 3 weeks after commencing treatment. Outcome measures were resumption of any sexual activity or condomless receptive anal sex within 1, 2, or 3 weeks after commencing treatment. Generalized linear regression was used to calculate adjusted risk ratios (aRR) to identify associated factors.

RESULTS

Almost 1 in 10 men (9.5%; 95% confidence interval [CI], 7.2-12.1) resumed condomless receptive anal sex within 1 week of commencing treatment. This was associated with current preexposure prophylaxis use (aRR, 3.4; 95% CI, 2.5-4.8]) and having 9 or more sexual partners in the last 3 months (aRR, 3.2; 95% CI, 1.6-5.0). Most men (75.0%; 95% CI, 71.3-78.5) resumed any sexual activity within 3 weeks; this was associated with a greater number of sexual partners (4-8 partners; aRR, 1.2; 95% CI, 1.1-1.5; ≥9 partners; aRR, 1.5; 95% CI, 1.3-1.7).

CONCLUSIONS

Resuming condomless receptive anal sex early after treatment may facilitate onward transmission and promote antimicrobial resistance for STIs. Although azithromycin remains a treatment option, this analysis highlights the need for new health promotion messages regarding early resumption of sex and continued surveillance for antimicrobial resistance.

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.

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).

Paying for Sex Among Males and Females: A Cross-Sectional Survey in Melbourne, Australia

BACKGROUND

Most research focuses on individual selling sex but very few on paying for sex. This study aimed to determine the proportion of males and females who paid for sex and associated factors.

METHODS

We conducted a short survey at the Melbourne Sexual Health Centre between March and April 2019, which included a question on whether they had paid for sex in the past 3 months. The proportion of individuals who had paid for sex was calculated by sex and sexual orientation. Univariable and multivariable logistic regression models were conducted to identify individual's factors (e.g., demographics, sexual orientation, and HIV/sexually transmitted infection [STI] positivity) associated with paying for sex in the past 3 months.

RESULTS

The proportion who reported paying for sex in the past 3 months was 12.2% (42/345) among heterosexual males, followed by 6.4% (23/357) among men who have sex with men (MSM) and 0.2% (1/430) among females. HIV status, preexposure prophylaxis use, and sexual orientation were not associated with paying for sex among MSM. No MSM living with HIV reported paying for sex in the past 3 months. There was a significant association between paying for sex and gonorrhea (odds ratio, 2.84; 95% confidence interval, 1.05-7.71; P = 0.041) but not HIV, syphilis, and chlamydia among MSM. HIV/STI was not associated with paying for sex among heterosexual males.

CONCLUSIONS

Paying for sex was more commonly reported among heterosexual males, followed by MSM. Females were very unlikely to pay for sex. There was a limited association between HIV/STI diagnosis and paying for sex among males.

The Duration of Pharyngeal Gonorrhea: A Natural History Study

BACKGROUND

Pharyngeal gonorrhea is relatively common. However, the duration of untreated pharyngeal gonorrhea is unknown.

METHODS

From March 2016 to December 2018, we enrolled 140 MSM in a 48-week cohort study. Participants self-collected pharyngeal specimens and completed a survey weekly. Specimens were tested using a nucleic acid amplification test at the conclusion of the study. We estimated the incidence and duration of infection. We defined incident infections as two consecutive positive tests, and clearance as two consecutive negative tests; and, after visual inspection of the data, we reclassified up to two weeks of missing or negative tests as positive if they occurred between 2 episodes of infections. We used Kaplan Meier estimates to define duration of infection. Lastly, we report on the frequency of single positive tests and the time between last negative test and the positive test.

RESULTS

Nineteen (13.6%) of 140 participants experienced 21 pharyngeal infections (incidence 31.7 per 100 person years (py); 95% CI 20.7 - 48.6 per 100 py). The estimated median duration of pharyngeal gonorrhea was 16.3 weeks (95%CI 5.1-19.7). Twenty-two men had 25 single positive specimens, a median of 7 days (IQR 7-10) following their last negative test.

CONCLUSIONS

The median duration of untreated pharyngeal gonorrhea is 16 weeks, more than double previous estimates. This long duration of infection likely contributes to high levels of gonorrhea transmission.

Comparison of the patterns of chlamydia and gonorrhoea at the oropharynx, anorectum and urethra among men who have sex with men

OBJECTIVE

Chlamydia and gonorrhoea are common sexually transmitted infections that infect the oropharynx, anorectum and urethra in men who have sex with men (MSM). This study aimed to examine the pattern of infection at more than one site (multisite) for chlamydia and gonorrhoea among MSM.

METHODS

This was a retrospective study of MSM attending the Melbourne Sexual Health Centre for the first time between 2018 and 2019. We included MSM aged ≥16 years who had tested for Neisseria gonorrhoeae and Chlamydia trachomatis at all three sites (oropharynx, anorectum and urethra). We compared infections that occurred at a single site (termed single-site infection) and those that occurred at more than one site (termed multisite infections).

RESULTS

Of the 3938 men who were tested for chlamydia and gonorrhoea, 498/3938 men (12.6%, 95% CI 11.5% to 13.6%) had chlamydia at any site, of whom 400/498 (80.3%, 95% CI 78.9% to 81.2%) had single-site chlamydia infection, and 98/498 (19.7%, 95% CI 16.2% to 23.1%) had multisite infections. A similar proportion of men had gonorrhoea at any site (447/3938, 11.4%, 95% CI 10.3% to 12.2%), but among these 447 men, single-site infection was less common (256/447, 57.3%, 95% CI 52.6% to 61.7%, p<0.001) and multisite infection (191/447, 42.7%, 95% CI 38.2% to 47.3%, p<0.001) was more common than chlamydia. There were also marked differences by anatomical site. Urethral infection commonly occurred as single sites (75/122, 61.5%, 95% CI 52.8% to 70.1%) for chlamydia but uncommonly occurred for gonorrhoea (12/100, 12.0%, 95% CI 5.6% to 18.3%, p<0.001). In contrast, anorectal infection uncommonly occurred as multisite infection for chlamydia (98/394, 24.9%, 95% CI 20.6% to 29.1%) but was common (184/309, 59.5%, 95% CI 54.0% to 64.9%, p<0.001) for gonorrhoea.

CONCLUSIONS

The markedly different pattern of site-specific infection for chlamydia and gonorrhoea infections among the same MSM suggests significant differences in the transmissibility between anatomical sites and the duration of each infection at each site.

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.

Neisseria species and their complicated relationships with human health

Neisseria spp. are a transient low abundance member of the human microbiome. This species contains the very well described pathogens, Neisseria gonorrhoeae and N. meningitidis. Recent advances in molecular typing have revealed that this genus is more diverse than previously thought and that commensal species may have important roles in inhibiting the growth the pathogens. This short review summates these new findings and examines the evidence that the relatively under-reported Neisseria commensal species maybe beneficial to human health.

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).

Sudden emergence of a Neisseria gonorrhoeae clade with reduced susceptibility to extended-spectrum cephalosporins, Norway

Neisseria gonorrhoeae multilocus sequence type (ST)-7827 emerged in a dramatic fashion in Norway in the period 2016-2018. Here, we aim to shed light on the provenance and expansion of this ST. ST-7827 was found to be polyphyletic, but the majority of members belonged to a monophyletic clade we termed PopPUNK cluster 7827 (PC-7827). In Norway, both PC-7827 and ST-7827 isolates were almost exclusively isolated from men. Phylogeographical analyses demonstrated an Asian origin of the genogroup, with multiple inferred exports to Europe and the USA. The genogroup was uniformly resistant to fluoroquinolones, and associated with reduced susceptibility to both azithromycin and the extended-spectrum cephalosporins (ESCs) cefixime and ceftriaxone. From a genetic background including the penA allele 13.001, associated with reduced ESC susceptibility, we identified repeated events of acquisition of porB alleles associated with further reduction in ceftriaxone susceptibility. Transmission of the strain was significantly reduced in Norway in 2019, but our results indicate the existence of a recently established global reservoir. The worrisome drug-resistance profile and rapid emergence of PC-7827 calls for close monitoring of the situation.

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.

Modelling the contribution that different sexual practices involving the oropharynx and saliva have on Neisseria gonorrhoeae infections at multiple anatomical sites in men who have sex with men

BACKGROUND

The spectrum of sexual practices that transmit Neisseria gonorrhoeae in men who have sex with men (MSM) is controversial. No studies have modelled potential Neisseria gonorrhoeae transmission when one sexual practice follows another in the same sexual encounter ('sequential sexual practices'). Our aim was to test what sequential practices were necessary to replicate the high proportion of MSM who have more than one anatomical site infected with gonorrhoea ('multisite infection').

METHODS

To test our aim, we developed eight compartmental models. We first used a baseline model (model 1) that included no sequential sexual practices. We then added three possible sequential transmission routes to model 1: (1) oral sex followed by anal sex (or vice versa) (model 2); (2) using saliva as a lubricant for penile-anal sex (model 3) and (3) oral sex followed by oral-anal sex (rimming) or vice versa (model 4). The next four models (models 5-8) used combinations of the three transmission routes.

RESULTS

The baseline model could only replicate infection at the single anatomical site and underestimated multisite infection. When we added the three transmission routes to the baseline model, oral sex, followed by anal sex or vice versa, could replicate the prevalence of multisite infection. The other two transmission routes alone or together could not replicate multisite infection without the inclusion of oral sex followed by anal sex or vice versa.

CONCLUSIONS

Our gonorrhoea model suggests sexual practices that involve oral followed by anal sex (or vice versa) may be important for explaining the high proportion of multisite infection.

Chlamydia trachomatis transmission between the oropharynx, urethra and anorectum in men who have sex with men: a mathematical model

BACKGROUND

It has been presumed that Chlamydia trachomatis is transmitted between men only through anal or oral sex, but no mathematical models have tested this presumption.

METHODS

To test this presumption, we created 20 compartmental mathematical models of different sexual practices that included both oral and anal sex and calibrated these models to the observed rates of Chlamydia trachomatis infection at three anatomical sites from 4888 men who have sex with men (MSM) in Melbourne Sexual Health Centre during 2018-2019.

RESULTS

A model that included only oral and anal sex could replicate the observed rates of single-site infection at the oropharynx, urethra and rectum alone, but could not replicate infection at more than one of these sites (multisite). However, if we included transmission from sexual practices that followed one another in the same sexual episode (e.g. saliva contamination of the penis from oral sex transmitting chlamydia to the rectum by anal sex), we significantly improved the calibration of multisite infection rates substantially.

CONCLUSIONS

Our modelling study suggests that transmission routes other than just oral and anal sex are necessary to explain the high rate of Chlamydia trachomatis infection at more than one site.

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.

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 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. For detailed background, evidence base and discussions, see the background review for the present 2020 European guideline for the diagnosis and treatment of gonorrhoea in adults (Unemo M, et al. Int J STD AIDS. 2020).

Men and Women Have Similar Neisseria gonorrhoeae Bacterial Loads: a Comparison of Three Anatomical Sites

Neisseria gonorrhoeae is a common bacterial sexually transmitted infection (STI). Currently, there are limited data on the bacterial load in both men and women and on both genital and extragenital sites. Therefore, we quantified N. gonorrhoeae bacterial loads in a large population of women, heterosexual men, and men who have sex with men (MSM) at three different anatomical sites. N. gonorrhoeae-positive samples (n = 1265) of STI clinic consultations (n = 944) were tested for N. gonorrhoeae with the Roche Cobas 4800 system, and quantification cycle (Cq) values were used as an inversely proportional measure for N. gonorrhoeae bacterial load after interpolation from a standard curve. Bacterial loads were compared between sample materials and sexes using t tests. The following mean N. gonorrhoeae loads were observed: urine, 4.5 ± 1.0 log₁₀ CFU/ml; vaginal swabs, 4.3 ± 1.1 log₁₀ CFU/ml; anorectal swabs (women), 4.0 ± 1.2 log₁₀ CFU/ml; anorectal swabs (men), 4.5 ± 1.3 log₁₀ CFU/ml; oropharyngeal swabs (women), 2.8 ± 0.9 log₁₀ CFU/ml; and oropharyngeal swabs (men), 3.2 ± 1.0 log₁₀ CFU/ml. Oropharyngeal swabs had a significantly lower N. gonorrhoeae load (P < 0.001) than genital and anorectal samples. Loads did not differ between men and women. This is the first study that determined N. gonorrhoeae load in both women and men at three anatomical sites. The substantial N. gonorrhoeae load at all sample sites suggest that all sites may have transmission potential. However, the oropharyngeal site presents the lowest bacterial load. Men and women have a similar N. gonorrhoeae loads on separate anatomical sites, arguing for similar transmission potential and similar clinical relevance.

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.

Changing from Clinician-Collected to Self-Collected Throat Swabs for Oropharyngeal Gonorrhea and Chlamydia Screening among Men Who Have Sex with Men

The coronavirus disease 2019 (COVID-19) pandemic has led many clinics to move from clinician-collected to self-collected oropharyngeal swabs for the detection of sexually transmitted infections (STIs). Before this change, however, self-collection was used primarily for genital and anorectal infections, with only limited studies on the performance of self-collection of oropharyngeal swabs for oropharyngeal STI detection. The Melbourne Sexual Health Centre (MSHC) changed from clinician-collected to self-collected oropharyngeal swabs for oropharyngeal gonorrhea and chlamydia screening on 16 March 2020 in order to reduce health care worker risk during the COVID-19 pandemic. We compared the proportions of valid and positive samples for gonorrhea and chlamydia among men who have sex with men (MSM) in two time periods; the clinician collection period, between 20 January and 15 March 2020, and the self-collection period, between 16 March and 8 May 2020. A total of 4,097 oropharyngeal swabs were included. The proportion of oropharyngeal swabs with equivocal or invalid results for Neisseria gonorrhoeae was higher in the self-collection period (1.6% [24/1,497]) than in the clinician collection period (0.9% [23/2,600]) (P = 0.038), but the proportions did not differ for the detection of Chlamydia trachomatis The positivity rates of oropharyngeal N. gonorrhoeae (adjusted prevalence ratio [PR], 1.07 [95% confidence interval {CI}, 0.85 to 1.34]) (P = 0.583) and oropharyngeal C. trachomatis (adjusted PR, 0.84 [95% CI, 0.51 to 1.39]) (P = 0.504) specimens did not differ between the two periods. Self-collected oropharyngeal swabs for the detection of N. gonorrhoeae and C. trachomatis have acceptable performance characteristics and, importantly, reduce health care worker exposure to respiratory infections.

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.

Bacterial Load of Chlamydia trachomatis in the Posterior Oropharynx, Tonsillar Fossae, and Saliva among Men Who Have Sex with Men with Untreated Oropharyngeal Chlamydia

The aim of this study was to determine whether Chlamydia trachomatis could be detected in saliva and if infection is specific to an anatomical site in the oropharynx. Men who have sex with men (MSM) who were diagnosed with oropharyngeal chlamydia at the Melbourne Sexual Health Centre in 2017-2018 were invited to participate upon returning for treatment. Swabs at the tonsillar fossae and posterior oropharynx and a saliva sample were collected. Throat samples were tested for C. trachomatis by the Aptima Combo 2 assay. The bacterial loads of C. trachomatis in all samples were assessed by quantitative PCR (qPCR) detecting the ompA gene. We calculated the positivity and bacterial load of C. trachomatis for all samples. Forty-two MSM were included. The median age was 28 years (interquartile range [IQR], 24 to 33 years). Thirty-two participants (76.2%; 95% confidence interval [CI], 60.5% to 87.9%) had C. trachomatis detected by qPCR at both the tonsillar fossae and the posterior oropharynx, followed by 9.5% (n = 4; 95% CI, 2.7% to 22.6%) positive at the posterior oropharynx only and 4.8% (n = 2; 95% CI, 0.58% to 16.2%) positive at the tonsillar fossae only. Twenty-nine MSM had C. trachomatis detected in saliva (69.0%; 95% CI, 52.9% to 82.3%). The median C. trachomatis load in saliva was 446 copies/ml (IQR, 204 to 1,390 copies/ml), that in the tonsillar fossae was 893 copies/swab (IQR, 390 to 13,224 copies/ml), and that in the posterior oropharynx was 1,204 copies/swab (IQR, 330 to 16,211). There was no significant difference in C. trachomatis load between the tonsillar fossae and the posterior oropharynx (P = 0.119). Among MSM with oropharyngeal chlamydia, nearly three-quarters had chlamydia DNA detected in saliva, although the viability and implications for transmission are unknown.