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

OBJECTIVES: Oropharyngeal gonorrhoea is common among men who have sex with men (MSM). We aimed to clarify which oral sex practices were independent risk factors for oropharyngeal gonorrhoea: tongue kissing, receptive oro-penile sex (fellatio) or insertive oro-anal sex (rimming), and whether daily use of mouthwash and recent antibiotic use was protective. METHODS: In 2015, we conducted an age-matched case-control study of MSM who attended the Melbourne Sexual Health Centre. Cases had tested positive for oropharyngeal gonorrhoea by nucleic acid amplification testing, and controls had tested negative. Questionnaire items included tongue kissing, oral sex practices, condom use, recent antibiotic use, mouthwash use and alcohol consumption. RESULTS: We identified 177 cases, age matched to 354 controls. In univariable analyses, cases were 1.90 times (95% CI 1.13 to 3.20) more likely than controls to have had casual sexual partners (CSP) in the preceding 3 months, were 2.17 times (95% CI 1.31 to 3.59) more likely to have kissed CSP and were 2.04 times (95% CI 1.26 to 3.30) more likely to have had receptive oro-penile sex with CSP. Oropharyngeal gonorrhoea was not associated with insertive oro-anal sex or mouthwash use. The number of CSP for tongue kissing and receptive oral sex and total CSP were highly correlated, and in multivariable analysis neither kissing nor receptive oro-penile sex was significantly associated with having oropharyngeal gonorrhoea, after adjusting for total number of CSP. CONCLUSIONS: The finding that oropharyngeal gonorrhoea was associated with a higher number of sexual partners but not specific sexual practices highlights the need for further research in the area of gonorrhoea transmission to define the probability of transmission from specific sex acts.

Associations Between Anorectal Chlamydia and Oroanal Sex or Saliva Use as a Lubricant for Anal Sex: A Cross-sectional Survey.

BACKGROUND: Receptive condomless anal sex is a known risk factor for anorectal chlamydia, but it remains unclear whether oroanal sex practices also contribute. We aimed to determine whether oroanal sex ("rimming"), fingering, or the use of saliva as anal lubricant are risk factors for anorectal chlamydia among men who have sex with men (MSM). METHODS: This cross-sectional study was conducted at Melbourne Sexual Health Centre from July 2014 to June 2015. Routinely collected computer-assisted self-interview data included demographics, number of sexual partners, and condom use. We added questions on receptive rimming, receptive fingering or penis "dipping," and the use of a partner's saliva as anal lubricant. RESULTS: A total of 1691 MSM completed the questionnaire and tested for anorectal chlamydia. In univariable analyses, anorectal chlamydia was associated with using a partner's saliva as lubricant (odds ratio [OR] 1.97, 95% confidence interval [CI] 1.26-3.09), receptive rimming (OR 1.59; 95% CI 1.04-2.45), and receptive fingering or dipping (OR 1.90; 95% CI 1.06-3.43). In multivariable analysis, anorectal chlamydia was not associated with these sexual practices, after adjusting for number of sexual partners, HIV status, known contact with chlamydia, and condom use. However, collinearity between sexual practices likely obscured associations with anorectal chlamydia, and further analyses suggested weak associations between these sexual practices and anorectal chlamydia. CONCLUSIONS: The use of a partner's saliva during receptive anal sex practices such as rimming, fingering, or penis dipping were weak risk factor for anorectal chlamydia in MSM. This contrasts with our previously reported findings that the use of saliva as anal lubricant is more strongly associated with anorectal gonorrhea.

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

BACKGROUND: Gonorrhoea notifications are rapidly rising in men who have sex with men (MSM). We developed a model to assess mouthwash as a novel intervention for gonorrhoea control. METHODS: We developed a model of Neisseria gonorrhoeae (NG) transmission to explain anatomic site-specific prevalence of gonorrhoea among MSM. The model was calibrated to available epidemiological and behavioral data. We estimated the contribution of various sexual acts to gonorrhoea incidence and evaluate the potential impacts of screening scale-up and utilization of mouthwash on the gonorrhoea epidemic. RESULTS: We calibrated the model to prevalence of oropharyngeal, anal, and urethral gonorrhoea of 8.6% (7.7-9.5%), 8.3% (7.4-9.1%), and 0.20% (0.04-0.35%), respectively, among MSM. Oropharynx to oropharynx transmission through kissing is estimated to account for nearly three quarters of all incident cases (71.6% [64.4-80.5%]) of gonorrhoea in MSM. Substantially increasing annual oropharynx screening for gonorrhoea from the current 40% to 100% may only halve the prevalence of gonorrhoea in MSM. In contrast, the use of mouthwash with moderate efficacy (additional 1% clearance per daily use) would further reduce the corresponding prevalence rates to 3.1% (2.2-4.4%), 3.8% (2.3-4.9%), and 0.10% (0.06-0.11%), and a high-efficacy mouthwash (additional 1.5% clearance per daily use) may further halve the gonorrhoea prevalence. Without oropharynx to oropharynx transmission, we could not replicate current prevalence data. CONCLUSIONS: Despite a dearth of empirical data, our model suggests that kissing could potentially play an important role in NG transmission among MSM. Control through sexually transmitted infection screening alone is unlikely to have a substantial impact on the gonorrhoea epidemic in MSM.

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

BACKGROUND: Gonorrhoea is one of the most common sexually transmissible infections in men who have sex with men (MSM). Gonorrhoea rates have increased substantially in recent years. There is concern that increasing gonorrhoea prevalence will increase the likelihood of worsening antibiotic resistance in Neisseria gonorrhoeae. A recent randomised controlled trial (RCT) demonstrated that a single-dose of mouthwash has an inhibitory effect against oropharyngeal gonorrhoea. We are conducting the first RCT to evaluate whether daily use of mouthwash could reduce the risk of acquiring oropharyngeal gonorrhoea. METHODS/DESIGN: The OMEGA (Oral Mouthwash use to Eradicate GonorrhoeA) study is a double-blind RCT and will be conducted at several sexual health clinics and high caseload General Practice (GP) clinics in Melbourne and Sydney, Australia. A total of 504 MSM attending the participating sites will be recruited. Participants will be randomised to either using 'Study mouthwash A' or 'Study mouthwash B' for 12 weeks. Study mouthwash A was inhibitory against N. gonorrhoeae in vitro, whereas study mouthwash B was not. Participants will be instructed to rinse and gargle the study mouthwash for 60 seconds every day. The primary outcome is the proportion of participants with oropharyngeal gonorrhoea detected by nucleic acid amplification test by 12 weeks. DISCUSSION: The results from this trial may provide a novel way to reduce gonorrhoea prevalence and transmission without the use of antibiotics that may be associated with development of resistance. If shown to be effective, the widespread use of mouthwash will reduce the prevalence of oropharyngeal gonorrhoea, which plays key role in driving the emergence of gonococcal antimicrobial resistance through DNA exchange with oral commensal bacteria. The anticipated net effect will be interruption of onward transmission of N. gonorrhoeae within high density sexual networks within MSM populations. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12616000247471 , registered on 23rd February 2016.

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.

Models of gonorrhoea transmission from the mouth and saliva.

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

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

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

Saliva use in sex: Associations with use of smartphone dating applications in men who have sex with men.

Smartphone dating applications have become a primary source for men who have sex with men (MSM) to meet sexual partners. It has been found that MSM who used smartphone dating applications are at higher risk of gonorrhoea, but the reasons remain unknown. This study aimed to investigate whether MSM who met their partners via smartphone dating applications are more likely to engage in sexual practices such as rimming (oro-anal sex), and use of partner's saliva as a lubricant, that are associated with the risk of gonorrhoea. A cross-sectional study was conducted among 1672 MSM attending the Melbourne Sexual Health Centre, Australia, between 31 July 2014 and 30 June 2015. Multivariate logistic regression was conducted to examine the associations between sources of meeting partners and the two aforementioned sexual practices. MSM who used smartphone dating applications were 1.78 (95% CI: 1.38-2.28) times more likely to get rimmed, and 1.63 (95% CI: 1.27-2.09) times more likely to use partner's saliva as a lubricant during anal sex, compared to other sources, after adjusting for age and other sources for meeting partners. These practices are highly associated with gonorrhoea.

Adherence to, and acceptability of, Listerine® mouthwash as a potential preventive intervention for pharyngeal gonorrhoea among men who have sex with men in Australia: a longitudinal study.

We investigated whether men who have sex with men (MSM) would use mouthwash daily to prevent pharyngeal gonorrhoea. Ten MSM attending the Melbourne Sexual Health Centre were asked to use a Listerine® alcohol-containing mouthwash daily for 14 days in August 2015. Mouthwash was used at least once daily for 133 of 140 person-days (95% of days; 95% confidence interval 90-98%). All 10 men were willing to use mouthwash on a daily basis, and nine men were willing to use mouthwash after oral sex. This study showed that daily use of mouthwash is an acceptable intervention to prevent pharyngeal gonorrhoea in MSM.