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

Pharyngeal gonococcal infection and the sensitivity of oral gargle samples in comparison to self-collected throat swabs for the detection of N. gonorrhoeae in persons in Tyrol, Austria

PURPOSE

Asymptomatic pharyngeal gonorrhoea could play an important role in transmission and should be screened for in persons at risk. We investigated the sensitivity of oral gargle samples to detect N. gonorrhoea and describe the frequency of infection by anatomical site.

METHODS

From June 2021 to July 2022 persons diagnosed with gonorrhoea in the STI/HIV department were asked to provide self-collected specimens for single-site testing by NAAT from throat (by gargling and swabbing), anorectum, and first-void urine.

RESULTS

104 episodes of gonorrhoea were analysed in 88 individuals. The median age was 33 years, 85 persons (96.5%) were male. The pharynx was the most common site of infection (71 cases, 68.2%); in 26 persons (25.0%) it was the only site of infection. Anorectal infection was detected in 65 cases (62.5%) and urogenital infection in 25 cases (24.0%). In 46 cases (44.2%) infection was detected in more than one anatomical site. Gargling was less sensitive than throat swabbing to detect pharyngeal infection (85.9% versus 97.2%, p = .038), but was preferred by patients. Only 4 of 71 pharyngeal infections (5.6%) were symptomatic; anorectal and urogenital infections were symptomatic in 12.3% and 76.0% of cases, respectively. Culture recovery of N.gonorrhoeae was only possible in 15.8% of throat swabs, but was successful in 61.9% of anorectal and 84.2% of urogenital samples.

CONCLUSIONS

Asymptomatic pharyngeal gonorrhoea is common. Gargle samples should be used only as alternative specimens with inferior sensitivity compared to throat swab samples.

Combinations of Sexual Activities During a Sex Episode with Recent Casual Male Partner Among Men Who Have Sex with Men: A Cross-Sectional Study

We examined combinations of nine sexual activities that occurred during a sex episode with a recent male partner among men who have sex with men (MSM) who attended an urban sexual health clinic from April-2017 to September-2017. We collected the following sexual activities: tongue-kissing, penises touching, using saliva during mutual masturbation, performed rimming, received rimming, performed fellatio, received fellatio, insertive anal sex, and receptive anal sex. During a single-sex episode, the most common combinations of sexual activities involved all nine activities (10.6%, 166/1542). We assessed the agreement between any two sexual activities that occurred together during a sex episode. Agreement was highest for receiving rimming and receptive anal sex (kappa = 0.40; 95% CI: 0.35, 0.45), and performing rimming and insertive anal sex (kappa = 0.38; 95% CI: 0.33, 0.42). Agreement was lowest for insertive anal sex and receiving fellatio (kappa = -0.01; 95% CI: -0.05, 0.03), and receptive anal sex and insertive anal sex (kappa = -0.08; 95% CI: -0.13, 0.03). The sexual activities that occur between men are correlated with one another and this will influence transmission between anatomical sites.

HIV-Negative MSM Infected with Two Different Isolates of Drug-Resistant Neisseria gonorrhoeae-Case Report

The antimicrobial resistance of Neisseria gonorrhoeae (NG) is an increasing public health concern, highlighted by the fact that gonococcus is considered as a 'high'-priority pathogen by the WHO for research and development of new therapeutic options. According to the data of the European Centre for Disease Prevention and Control (ECDC) in 2022, the rate of NG infections is the highest recorded since European surveillance of sexually transmitted infections began in 2009. We report a brief description of a patient infected with two different isolates of drug-resistant N. gonorrhoeae. N. gonorrhoeae cultures were positive from oropharyngeal and urethral swabs and isolates had different antimicrobial susceptibility. We investigated the antimicrobial susceptibility of these isolates to six antimicrobials (ceftriaxone, cefixime, azithromycin, ciprofloxacin, tetracycline, and benzylpenicillin), and minimum inhibitory concentrations (MICs; mg/L) were determined using Etest on gonococcal isolates. Oropharyngeal isolate was resistant to azithromycin while urethral was resistant to penicillin, ciprofloxacin, and tetracycline. Two different and phylogenetically distinct sequence types of NG isolates were identified. Understanding the dynamics and drivers of resistance spread can provide an improved rationale for antibiotic management, and the level of NG resistance should be monitored closely.

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.

Clinic-based evaluation of the dual Xpert CT/NG assay on the GeneXpert System for screening for extragenital chlamydial and gonococcal infections amongst men who have sex with men

BACKGROUND

Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections have increased globally. Asymptomatic infections represent a significant risk of long-term complications. Men who have sex with men (MSM) are disproportionally affected, underscoring the need to offer screening programmes to this population. CT/NG Point of Care Testing (POCT) constitutes a strategic tool to improve the continuum of STI care, however extensive real-life evaluations amongst at risk populations are lacking. The aim of this study is to estimate the GeneXpert CT/NG assay performance and usability for CT and NG at genital and extragenital sites for screening amongst MSM.

METHODS

This study was a multi-site sexual health clinic-based evaluation (Italy, Malta and Peru) with consecutive enrolment. A first void urine sample (divided in two aliquots), two oropharyngeal and two anorectal swabs were collected for each study participant. One specimen set (one for each anatomical site) was tested with the dual index test (Cepheid) at the clinics by the healthcare staff, the other set with FDA/CE approved Nucleic Acid Amplification Tests (NAATs) at the laboratory. Clinical sites and reference laboratories participated in an internal and external quality control programme. Sensitivity, specificity, positive and negative likelihood ratios, positive and negative predictive values for each anatomical site were estimated using a meta-analytic approach.

RESULTS

One thousand seven hundred two MSM were recruited across all clinical sites for a total of 5049 biological specimens. NG and CT were respectively detected in 274 and 287 of samples. Overall, the NG POCT sensitivity and specificity was 91.43% and 99.75% in urine (LR + 372.80, LR- 0.09), 89.68% and 99.55% in rectal specimens (LR + 197.30, LR- 0.10) and 75.87% and 98.77% at the pharynx respectively (LR + 61.94, LR- 0.24). The CT component of the POCT sensitivity was 84.82% and specificity 99.63% in urine (LR + 228.68, LR- 0.15), 78.07% and 99.19% respectively on rectal site (LR + 96.23, LR-0.22), 67.79% and 99.88% respectively at pharyngeal site (LR + 554.89, LR- 0.32). 95.95% of MSM reported to be willing to wait for POCT results and no provider reported difficulties in terms of performance or interpretation of the results of the Xpert CT/NG.

CONCLUSION

Rapid turnaround time, ease of use and high acceptability make the Xpert CT/NG testing system a strategic tool for increasing testing frequency, reaching those not yet tested and offering the possibility of immediate treatment if needed. The assay showed good negative likelihood ratios and confirms its use to rule out CT/NG infections. Sensitivity varied across sites and pathogens. Periodic staff training at the testing sites should be mandatory.

Patterns of Chlamydia trachomatis and Neisseria gonorrhoeae in different anatomical sites among Pre-Exposure Prophylaxis (PrEP) users in Brazil

BACKGROUND

The presence of untreated sexually transmitted infections (STIs) significantly increases the chance of acquiring HIV. In Brazil, testing for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) among Pre-Exposure Prophylaxis (PrEP) users is insufficient, and syndromic treatment is a priority in clinical practice. Multi-site testing for CT/NG improves thescreening of asymptomatic cases and ensures timely treatment. Therefore, it is essential for HIV prevention. This study aims to test the importance of two-site testing for better screening of these pathogens and to determine whether the presence of symptoms is an indicator of CT/NG infection.

METHODS

This is a cross-sectional study carried out in four public infectious diseases clinics in São Paulo State, Brazil between January of 2022 and March of 2023. All participants had an anal swab and a first-pass or mid-stream urine collected for CT/NG analysis by Polymerase chain reaction (PCR). Data about sociodemographic, sexual behavioural and clinical aspects were collected. Pathway analysis was used to examine the direct and indirect relationships between variables according to the theoretical model.

RESULTS

We screened 171 PrEP users which had two samples collected, resulting in 342 samples. Comparing the anatomic sites, the urine samples showed lower sensitivity for CT and NG than anal samples. Gonorrhoea was directly linked to lower age (β= -0.161, p = 0.001). Time of PrEP use was directly associated with CT infection (β = 0.202; p = 0.042) and inversely associated with dysuria (β= -0.121, p = 0.009). Lower occurrence of yellow-green secretion was linked to detection of CT (β= -0.089, p = 0.005) and NG (β= -0.048, p = 0.002) infections. Foul-smelling discharge was directly associated with CT (β = 0.275, p = 0.004) and NG (β = 0.295, p = 0.037) infection.

CONCLUSION

The symptoms are a bad indicator of CT and NG infection, and the screening must be done in more than one site since most of the positive results would be missed if only urines were tested. In the case of testing only one anatomical site, specifically the urethra, the CT/NG incidence and prevalence would be underestimated. The two-sites testing improves detection rates of CT/NG, and PrEP follow-up benefits people offering STI testing.

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.

Frequent screening for asymptomatic chlamydia and gonorrhoea infections in men who have sex with men: time to re-evaluate?

There is increasing debate regarding the harms and benefits of frequent asymptomatic screening for Chlamydia trachomatis and Neisseria gonorrhoeae in men who have sex with men (MSM). One concern is that frequent asymptomatic screening could result in increased antimicrobial resistance in an array of sexually acquired infections and other pathogens, due to selection pressure exerted by frequent broad-spectrum antimicrobial usage within some sexual networks. Here, we outline the harms and benefits of frequent C trachomatis and N gonorrhoeae screening in MSM in high-income settings and propose that screening frequency be reduced. We describe the evidence gaps that should be further explored to better understand the implications of reducing the frequency of asymptomatic C trachomatis and N gonorrhoeae screening in MSM and the surveillance systems that should be in place to prepare for such changes.

Update on the Epidemiology, Screening, and Management of Chlamydia trachomatis Infection

Chlamydia trachomatis infection ("chlamydia") is the most commonly diagnosed bacterial sexually transmitted infection globally, occurring in the genitals (urethra or vagina/cervix), rectum, or pharynx. If left untreated in women, genital chlamydia can ascend into the upper genital tract causing pelvic inflammatory disease, increasing their risk for ectopic pregnancy, infertility, and chronic pelvic pain. In men, chlamydia can cause epididymitis and proctitis. However, chlamydia is asymptomatic in over 80% of cases. This article provides an update on the epidemiology, natural history, and clinical manifestations of chlamydia in adults and discusses the current approaches to its management and control policy.

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.

Sexual Activities and Changes in Condom Use in Group Sex Events Among Female Sex Workers in Melbourne, Australia

Background

There are few studies investigating group sex among female sex workers (FSWs). This study aimed to examine the typical number of group sex participants, sexual activities and condom use in group sex among FSWs attending a sexual health clinic in Melbourne, Australia.

Methods

We conducted a cross-sectional survey between May 1, 2019 and March 13, 2020 among FSWs in Melbourne. Participants were asked whether they had participated in group sex (sex involving more than two participants) within the past 3 months, the size of the most recent group sex event, sexual activities they engaged in and condom use. It is unknown whether this was a paid or unpaid event in our study.

Results

Of the 247 FSWs surveyed, the mean age was 28.9 years and 51.8% were born in Australia. More than a quarter (27.5%, n = 68) had had group sex in the past 3 months with the number of events ranging from 1 to 10 times. The median size of the group was 3 participants with one man and two women (including the FSW) being the most common combination. Kissing was the most common activity in group sex. Of 58 FSWs who had vaginal sex during group sex, 77.3% (51/58) reported their male partners always used condoms but 13.7% (7/51) of these did not change condoms between women.

Conclusion

This study finds that group sex is common among FSWs. Although condoms are always used during group sex, one in six men did not change their condoms between partners, which may increase STI transmission between partners.

Controversies and evidence on Chlamydia testing and treatment in asymptomatic women and men who have sex with men: a narrative review

Background

Chlamydia trachomatis (CT) is the most common bacterial sexually transmitted infection (STI) worldwide. CT is mainly asymptomatic. Test-and-treat strategies are widely implemented to prevent transmission and complications. Strategies are not without controversy in asymptomatic women and men who have sex with men (MSM). Concerns are emerging to test and treat asymptomatic persons for urogenital CT (‘Controversy 1’) and pharyngeal or rectal CT (‘Controversy 2’), whereby testing symptomatic persons is not under debate. Opposed views in CT treatment involve using azithromycin versus doxycycline (‘Controversy 3’). The objective of this review is to provide coverage of these public health and clinical controversies by reviewing the current scientific evidence.

Methods

A literature search was performed using PubMed for relevant publications between 2018 and September 2021, and iterative retrieval of additional relevant publications.

Results

Controversy 1. In women, the majority of asymptomatic CT are at the urogenital site, and detections mostly include viable CT. CT easily transmits to a partner and potentially also between the vaginal and rectal areas; the clinical impact of urogenital CT is established, although risks for adverse outcomes are uncertain. Wide-scale testing in asymptomatic women has not resulted in reduced prevalence. In MSM, evidence for the clinical impact of asymptomatic urogenital CT is lacking. Controversy 2. Rectal CT is common in women diagnosed with urogenital CT, but the clinical impact of asymptomatic rectal CT is uncertain. In MSM, rectal CT is common, and most CT infections are at the rectal site, yet the risk of longer term complications is unknown. In both sexes, pharyngeal CT is uncommon and has no documented clinical impact. Controversy 3. In the treatment of rectal CT, doxycycline has superior effectiveness to azithromycin. Evidence has also accumulated on the harms of test-and-treat strategies.

Conclusions

Current practices vary widely, from widescale test-and-treat approaches to more individual patient- and partner-level case management. Choosing which asymptomatic people to test at what anatomic site, and whether to test or not, requires an urgent (re-)definition of the goals of testing and treating asymptomatic persons. Treatment guidelines are shifting toward universal doxycycline use, and clinical practice now faces the challenge of implementation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07171-2.

Test-and-treat is a key strategy in the control of Chlamydia trachomatis (CT). We discuss recent controversies and present scientific evidence regarding urogenital, rectal, and pharyngeal CT test-and-treat strategies in women and in men who have sex with men (MSM). This should inform best practices for the prevention and management of the most common bacterial sexually transmitted infection (STI) worldwide.

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.

Diagnostic accuracy of pooling urine, anorectal, and oropharyngeal specimens for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae: a systematic review and meta-analysis

BACKGROUND

Screening for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) at genital and extragenital sites is needed for most key populations, but molecular diagnostic tests for CT/NG are costly. We aimed to determine the accuracy of pooled samples from multiple anatomic sites from one individual to detect CT/NG using the testing of a single sample from one anatomic site as the reference.

METHODS

In this systematic review and meta-analysis, we searched five databases for articles published from January 1, 2000, to February 4, 2021. Studies were included if they contained original data describing the diagnostic accuracy of pooled testing compared with single samples, resource use, benefits and harms of pooling, acceptability, and impact on health equity. We present the pooled sensitivities and specificities for CT and NG using a bivariate mixed-effects logistic regression model. The study protocol is registered in PROSPERO, an international database of prospectively registered systematic reviews (CRD42021240793). We used GRADE to evaluate the quality of evidence.

RESULTS

Our search yielded 7814 studies, with 17 eligible studies included in our review. Most studies were conducted in high-income countries (82.6%, 14/17) and focused on men who have sex with men (70.6%, 12/17). Fourteen studies provided 15 estimates for the meta-analysis for CT with data from 5891 individuals. The pooled sensitivity for multisite pooling for CT was 93.1% [95% confidence intervals (CI) 90.5-95.0], I²=43.3, and pooled specificity was 99.4% [99.0-99.6], I²=52.9. Thirteen studies provided 14 estimates for the meta-analysis for NG with data from 6565 individuals. The pooled sensitivity for multisite pooling for NG was 94.1% [95% CI 90.9-96.3], I²=68.4, and pooled specificity was 99.6% [99.1-99.8], I²=83.6. Studies report significant cost savings (by two thirds to a third).

CONCLUSION

Multisite pooled testing is a promising approach to improve testing coverage for CT/NG in resource-constrained settings with a small compromise in sensitivity but with a potential for significant cost savings.

Triple site sexually transmitted infection testing as a crucial component of surveillance for men who have sex with men: A prospective cohort study

Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections are common among men who have sex with men (MSM). Many oropharyngeal and anorectal infections remain asymptomatic. We aimed to evaluate triple-site screening following PrEP introduction. We enrolled a prospective cohort study including 210 asymptomatic MSM during 2019-2020, analyzed by groups: HIV positive (HIV+), HIV-uninfected using PrEP (HIV-/PrEP+), or HIV-uninfected not using PrEP (HIV-/PrEP-). A self-administered questionnaire captured demographic information and sexual risk-taking behaviors. CT/NG testing results were compared between study groups and predictors of infection were evaluated. We included 59 HIV+, 70 HIV-/PrEP+, and 81 HIV-/PrEP- subjects. 30% (n = 62) of participants tested positive for CT/NG. HIV-/PrEP+ group had highest proportion of infections (n = 33, 47%) followed by HIV-/PrEP- (n = 16, 22%) and HIV+ (n=13, 20%; p < .001). Importantly, 98% (80/82) of pharyngeal/anorectal CT/NG infections were missed in genitourinary tract screening alone. PrEP use and previous syphilis infection were the strongest risk factor for CT/NG. Extra-genital asymptomatic CT/NG infections were prevalent among MSM. These data highlight the importance of routine extra-genital CT/NG testing in asymptomatic sexually active MSM. The study describes the consequences for three-site testing lack of implementation in the PrEP era.

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.

Role of saliva use during masturbation in the transmission of Chlamydia trachomatis in men who have sex with men

Masturbation is a common sexual practice in men, and saliva is often used as a lubricant during masturbation by men who have sex with men. However, the role of saliva use during masturbation in the transmission of chlamydia is still unclear. We developed population-level, susceptible-infected-susceptible compartmental models to explore the role of saliva use during masturbation on the transmission of chlamydia at multiple anatomical sites. In this study, we simulated both solo masturbation and mutual masturbation. Our baseline model did not include masturbation but included transmission routes (anal sex, oral-penile sex, rimming, kissing and sequential sexual practices) we have previously validated (model 1). We added masturbation to model 1 to develop the second model (model 2). We calibrated the model to five clinical datasets separately to assess the effects of masturbation on the prevalence of site-specific infection. The inclusion of masturbation (model 2) significantly worsened the ability of the models to replicate the prevalence of C. trachomatis. Using model 2 and the five data sets, we estimated that saliva use during masturbation was responsible for between 3.9% [95% confidence interval (CI) 2.0–6.8] and 6.2% (95% CI 3.8–10.5) of incident chlamydia cases at all sites. Our models suggest that saliva use during masturbation is unlikely to play a major role in chlamydia transmission between men, and even if it does have a role, about one in seven cases of urethral chlamydia might arise from masturbation.