What Is the Optimal Testing Strategy for Oropharyngeal Neisseria gonorrhoeae in Men Who Have Sex With Men? Comparing Selective Testing Versus Routine Universal Testing From Dutch Sexually Transmitted Infection Clinic Data (2008-2017)

Provider uptake of extragenital screening for gonorrhea and chlamydia in a cohort of Air Force members with incident HIV diagnosis

The prevalence of Neisseria gonorrhea (GC) and Chlamydia trachomatis (CT) is higher at extragenital anatomic sites among men who have sex with men (MSM) with HIV infection. Although national guidelines recommend that all MSM with HIV infection undergo screening for extragenital sexually transmitted infections (EG-STIs), uptake is low in many primary care settings. We evaluated EG-STI screening by primary care providers (PCPs) for US Air Force (USAF) members with incident HIV infection. All USAF members with incident HIV infection who received initial HIV specialty care with Infectious Disease (ID) providers at Brooke Army Medical Center from 2016 to 2018 (n = 98) were included. A retrospective chart review was conducted to evaluate STI screening performed by PCPs within 1 week of HIV diagnosis compared to screening at entry into ID care. Demographic, clinical, laboratory and behavioral risk data were collected. STI screening included GC/CT EG-STIs, urethral GC/CT, syphilis, and hepatitis B and C. Patients were predominantly male (98%) with a median age of 26 (IQR 23, 32) years at HIV diagnosis. A previous history of STIs was reported in 53 (54%) patients and the majority of males self-identified as MSM (66%) or bisexual (23%). The median time from HIV diagnosis to ID evaluation was 26 days (IQR 9, 33). PCPs performed any STI screening in 61 (62%) patients. EG-STI screening was conducted in 3 (3%) patients overall and in (3%) MSM/bisexuals. A total of 31 (32%) patients had missed STIs; the majority due to EG-STIs of the rectum (59%) and pharynx (19%). All EG-STIs would have been missed by urethral GC/CT screening alone. EG-STI screening uptake was low among PCPs evaluating USAF members with incident HIV infection. Underutilization of EG-STI screening can result in missed infections and forward transmission of GC/CT. Barriers to low uptake need to be explored.

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.

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

OBJECTIVES

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

DESIGN

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

SETTING

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

PARTICIPANTS

Published available data on MSM with multisite infections of gonorrhoea.

PRIMARY AND SECONDARY OUTCOME MEASURES

Incidence of gonorrhoea.

RESULTS

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

CONCLUSIONS

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

Confirmatory testing of Neisseria gonorrhoeae in a sexual health clinic: implications for epidemiology and treatment policy

OBJECTIVES

European guidelines advise the use of dual nucleic acid amplification tests (NAAT) in order to minimise the inappropriate diagnosis of Neisseria gonorrhoeae (Ng) in urogenital samples from low prevalence areas and in extragenital specimens. In this cross-sectional study, we investigated the effect of confirmatory testing and confirmation policy on the Ng-positivity in a population visiting the sexual health clinic in Rotterdam, the Netherlands.

METHODS

Apart from urogenital testing, extragenital (oropharyngeal/anorectal) testing was performed for men who have sex with men (MSM) and according to sexual exposure for women and heterosexual men. Ng detection using NAAT was performed using BD Viper and for confirmatory testing BD MAX. Sexual transmitted infection consultation data were merged with diagnostic data from August 2015 through May 2016.

RESULTS

In women (n=4175), oral testing was performed in 84% and 22% were tested anally. In MSM (n=1828), these percentages were 97% and 96%, respectively. Heterosexual men (n=3089) were tested urogenitally. After confirmatory testing, oropharyngeal positivity rates decreased from 7.3% (95% CI 6.5 to 8.2) to 1.5% (95% CI 1.1 to 1.8) in women and from 13.9% (95% CI 12.3 to 15.5) to 5.4% (95% CI 4.3 to 6.4) in MSM. Anorectal positivity rates decreased from 2.6% (95% CI 1.6 to 3.7) to 1.8% (95% CI 0.9 to 2.6) in women and from 9.3% (95% CI 7.9 to 10.7) to 7.2% (95% CI 6.0 to 8.5) in MSM. Urogenital Ng-positivity rate ranged between 3.0% and 4.4% and after confirmation between 2.3% and 3.9%. When confirming oropharyngeal samples, Ng-positivity was 3.8% in women, 3.0% in heterosexual men and 12.5% in MSM. Additional confirmation of urogenital and anorectal samples led to 3.0% Ng positivity in women, 2.7% in heterosexual men and 11.4% in MSM.

CONCLUSIONS

Confirmation of urogenital and anorectal samples reduced the Ng-positivity rates, especially for women. However, as there is no gold standard for the confirmation of Ng infection, the dilemma within public health settings is to choose between two evils: missing diagnoses or overtreatment. In view of the large decrease in oropharyngeal positivity, confirmation Ng-positivity in oropharyngeal samples remains essential to avoid unnecessary treatment.

Routine universal testing versus selective or incidental testing for oropharyngeal Neisseria gonorrhoeae in women in the Netherlands: a retrospective cohort study

BACKGROUND

Women are not routinely tested for oropharyngeal Neisseria gonorrhoeae. At present, selective testing based on sexual behaviour or risk groups is advocated by international guidelines. Many oropharyngeal infections are asymptomatic and thus remain undetected, establishing a reservoir for ongoing transmission. Data on effectiveness of routine testing are scarce, thus we aimed to assess the optimal testing strategy for oropharyngeal N gonorrhoeae in women.

METHODS

In this retrospective cohort study, we used surveillance data obtained from all sexually transmitted infection (STI) clinics in the Netherlands between Jan 1, 2008, and Dec 31, 2017. We collected consultation-level data, and individual-level patient data from 2016 onwards, on sociodemographic characteristics, sexual behaviour in the past 6 months, self-reported symptoms, and STI diagnoses. We compared the prevalence of oropharyngeal N gonorrhoeae between women who attended clinics that offered routine universal testing (defined as >85% of women tested per clinic-year) and women who attended clinics that offered selective testing (defined as 5-85% of women tested per clinic-year) or incidental testing (<5% of women tested per clinic-year). We calculated the number of infections missed by selective testing by extrapolating prevalence for the routine universal testing group to that of weighted and unweighted samples of all selectively tested women. We used multivariable generalised estimating equations to identify independent risk factors for oropharyngeal N gonorrhoeae to identify the optimal selective testing strategy.

FINDINGS

554 266 consultations with at least one N gonorrhoeae test were recorded, of which 545 750 consultations (including repeat visits) were included in the analyses. Of 545 750 consultations, routine universal testing was used in 57 359 (10·5%), selective testing in 444 283 (81·4%), and incidental testing in 44 108 (8·1%). The prevalence of oropharyngeal N gonorrhoeae was 1·4% (95% CI 1·3-1·5; 703 of 50 962 consultations) in the routine testing group compared with 1·4% (1·3-1·5; 1858 of 132 276) in the selective testing group (p=0·68) and 2·8% (1·9-3·9; 30 of 1088) in the incidental testing group (p<0·0001). The prevalence of oropharyngeal-only infections was 47·7% (335 of 703 women) in the routine testing group, 53·3% (991 of 1858) in the selective testing group, and 60·0% (18 of 30) in the incidental testing group. Selective testing would have missed an estimated 4363 (70%; 95% CI 69-71) of all 6221 oropharyngeal N gonorrhoeae infections. Independent risk factors for oropharyngeal N gonorrhoeae were being notified for any STI (adjusted odds ratio 2·1, 95% CI 1·5-3·0), reporting sex work (4·0, 2·3-6·7), and having concurrent genital (51·5, 34·1-77·7) or anorectal (2·6, 1·4-4·8) N gonorrhoeae. Selective testing of women notified for any STI, or who reported sex work, would have led to 5418 (27·8%) of 19 455 women being tested and would have identified 119 (55·6%) of 214 oropharyngeal N gonorrhoeae infections.

INTERPRETATION

Selective testing potentially misses more than two-thirds of oropharyngeal N gonorrhoeae infections in women, of whom half have oropharyngeal infections without concurrent genital or anorectal infections. Using independent risk factors for oropharyngeal infection to guide testing is a minimal testing strategy. Routine universal testing is the optimum scenario to detect the majority of infections. However, future studies are needed to assess the cost-effectiveness of routine testing and its effect on antimicrobial resistance.

FUNDING

Public Health Service South Limburg.

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.

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.

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.