What proportion of episodes of gonorrhoea and chlamydia becomes symptomatic?

Review of mathematical models of Neisseria gonorrhoeae vaccine impact: Implications for vaccine development

An effective prophylactic vaccine for prevention of Neisseria gonorrhoeae infection would have a major impact on sexual and reproductive health worldwide. Interest in developing gonorrhoea vaccines is growing due to the reported high rates of N. gonorrhoeae infections globally, and the threat of antimicrobial resistance. Several gonorrhoea vaccine candidates are currently under evaluation and various mathematical models have been used to assess the potential population-level impact a gonorrhoea vaccine may have once available. Here we review key aspects of gonorrhoea vaccine mathematical modelling studies, including model structures, populations considered, and assumptions used as well as vaccine characteristics and implementation scenarios investigated. The predicted vaccine impact varied between studies, ranging from as little as ∼17 % reduction in N. gonorrhoeae prevalence after 30 years up to 100 % reduction after 5 years. However, all studies predicted that even a partially effective gonorrhoea vaccine could have a substantial impact in reducing N. gonorrhoeae prevalence or incidence, particularly when high coverage is achieved within either important risk groups or the overall sexually active population. As expected, higher vaccine efficacy against acquisition of N. gonorrhoeae and longer duration of protection were linked to greater reductions in infections. A vaccine that alters onward transmission could also substantially reduce infections. Several gaps and research needs have been identified by researchers in the field and via this narrative literature review. For example, future modelling to inform gonorrhoea vaccine development and implementation should consider additional populations that are at high risk of N. gonorrhoeae infection, especially in low- and middle-income settings, as well as the impact of vaccination on the potential adverse sexual and reproductive health outcomes of infection. In addition, more detailed and robust epidemiological, biological, and behavioural data is needed to enable more accurate and robust modelling of gonorrhoea vaccine impact to inform future scientific and public health decision-making.

Exploring Whether the Electronic Optimization of Routine Health Assessments Can Increase Testing for Sexually Transmitted Infections and Provider Acceptability at an Aboriginal Community Controlled Health Service: Mixed Methods Evaluation

BACKGROUND

In the context of a syphilis outbreak in neighboring states, a multifaceted systems change to increase testing for sexually transmitted infections (STIs) among young Aboriginal people aged 15 to 29 years was implemented at an Aboriginal Community Controlled Health Service (ACCHS) in New South Wales, Australia. The components included electronic medical record prompts and automated pathology test sets to increase STI testing in annual routine health assessments, the credentialing of nurses and Aboriginal health practitioners to conduct STI tests independently, pathology request forms presigned by a physician, and improved data reporting.

OBJECTIVE

We aimed to determine whether the systems change increased the integration of STI testing into routine health assessments by clinicians between April 2019 and March 2020, the inclusion of syphilis tests in STI testing, and STI testing uptake overall. We also explored the understandings of factors contributing to the acceptability and normalization of the systems change among staff.

METHODS

We used a mixed methods design to evaluate the effectiveness and acceptability of the systems change implemented in 2019. We calculated the annual proportion of health assessments that included tests for chlamydia, gonorrhea, and syphilis, as well as an internal control (blood glucose level). We conducted an interrupted time series analysis of quarterly proportions 24 months before and 12 months after the systems change and in-depth semistructured interviews with ACCHS staff using normalization process theory.

RESULTS

Among 2461 patients, the annual proportion of health assessments that included any STI test increased from 16% (38/237) in the first year of the study period to 42.9% (94/219) after the implementation of the systems change. There was an immediate and large increase when the systems change occurred (coefficient=0.22; P=.003) with no decline for 12 months thereafter. The increase was greater for male individuals, with no change for the internal control. Qualitative data indicated that nurse- and Aboriginal health practitioner-led testing and presigned pathology forms proved more difficult to normalize than electronic prompts and shortcuts. The interviews identified that staff understood the modifications to have encouraged cultural change around the role of sexual health care in routine practice.

CONCLUSIONS

This study provides evidence for the first time that optimizing health assessments electronically is an effective and acceptable strategy to increase and sustain clinician integration and the completeness of STI testing among young Aboriginal people attending an ACCHS. Future strategies should focus on increasing the uptake of health assessments and promote whole-of-service engagement and accountability.

Management of asymptomatic sexually transmitted infections in Europe: towards a differentiated, evidence-based approach

Most sexually transmitted infections (STIs) can be accurately diagnosed and treated during asymptomatic carriage. Widespread screening for these STIs is therefore assumed to be an effective way to reduce their prevalence and associated disease. In this review, we provide evidence that this is the case for HIV and syphilis. However, for other STIs such as Neisseria gonorrhoeae and Chlamydia trachomatis, our review reveals that the evidence that screening reduces infection prevalence and associated disease is weak. There is also growing evidence of harms from screening that might outweigh any benefits. The harms include the increased consumption of antimicrobials that follows frequent screening and increased detection of asymptomatic STIs in key populations, such as men who have sex with men taking HIV pre-exposure prophylaxis, and associated risk of antimicrobial resistance in target and non-target organisms. There may also be psycho-social harm associated with an STI diagnosis. We conclude that in the absence of symptoms, in high STI prevalence populations frequent STI screening should be limited to HIV and syphilis.

Extragenital Sexually Transmitted Infection Testing Among Louisiana Parish Health Units, 2016-2019

BACKGROUND

The Centers for Disease Control and Prevention recommends that men who have sex with men (MSM) get tested annually for urethral and rectal chlamydia (CT) and gonorrhea (NG), and pharyngeal NG. There are no national recommendations to screen women and heterosexual men at extragenital sites. We assessed extragenital CT/NG screening among men and women at Louisiana's Parish Health Units (PHU).

METHODS

The Louisiana STD/HIV/Hepatitis Program piloted extragenital screening at 4 PHUs in February 2016 and expanded to 11 PHUs in 2017. Sexual histories were used to identify gender of sex partners and exposed sites. Because of billing restrictions, up to 2 anatomical sites were tested for CT/NG.

RESULTS

From February 2016 to June 2019, 70,895 urogenital and extragenital specimens (56,086 urogenital, 13,797 pharyngeal, and 1,012 rectal) were collected from 56,086 patients. Pharyngeal CT positivity was 160 of 7,868 (2.0%) among women, 54 of 4,838 (1.1%) among men who have sex with women (MSW) and 33 of 1,091 (3.0%) among MSM. Rectal CT positivity was 51 of 439 (11.6%) among women and 95 of 573 (16.6%) among MSM. Pharyngeal NG positivity was 299 of 7,868 (3.8%) among women, 222 of 4,838 (4.6%) among MSW, and 97 of 1,091 (8.9%) among MSM. Rectal NG positivity was 20 of 439 (4.6%) among women and 134 of 573 (23.4%) among MSM.Urogenital-only screening would have missed: among women, 173 of 3,923 (4.4%) CT and 227 of 1,480 (15.3%) NG infections; among MSW, 26 of 2,667 (1%) CT and 149 of 1,709 (8.7%) NG infections; and among MSM, 116 of 336 (34.5%) CT and 127 of 413 (42.1%) NG infections.

CONCLUSIONS

Many CT/NG infections would have been missed with urogenital-only screening. Men who have sex with men had much higher extragenital infection rates than women and MSW.

Sex and Gender Differences in Bacterial Infections

There is a growing awareness of the importance of sex and gender in medicine and research. Women typically have stronger immune responses to self and foreign antigens than men, resulting in sex-based differences in autoimmunity and infectious diseases. In both animals and humans, males are generally more susceptible than females to bacterial infections. At the same time, gender differences in health-seeking behavior, quality of health care, and adherence to treatment recommendations have been reported. This review explores our current understanding of differences between males and females in bacterial diseases. We describe how genetic, immunological, hormonal, and anatomical factors interact to influence sex-based differences in pathophysiology, epidemiology, clinical presentation, disease severity, and prognosis, and how gender roles affect the behavior of patients and providers in the health care system.

Evaluating the impact and cost-effectiveness of chlamydia management strategies in Hong Kong: A modeling study

Objectives

To illustrate the epidemiologic and cost-effectiveness impact of shifting the focus from population-based screening toward a targeted management approach for genital chlamydia infection.

Design

Modeling study, implementing an individual-based, stochastic, dynamic network model.

Setting

Hong Kong.

Population

A hypothetical sample network of 10,000 people with a partnership distribution based on Hong Kong's sexually active population of reproductive age (age 18–49 years).

Interventions

In this study, we present several scenarios with different implementations of universal vs. targeted screening (based on partner numbers). We also explored the impact of (1) screening only, (2) screening plus expedited partner therapy, and (3) screening plus partner testing.

Primary outcome measures

Change of chlamydia prevalence before and after implementing the different strategies. The cost-effectiveness analysis reports total direct cost from a health provider perspective, the QALYs gained, and incremental cost-effectiveness ratios (ICER).

Results

In comparing the effects of universal screening only and targeted screening of the high-risk population, the mean prevalence during the 10th year of intervention was 2.75 ± 0.30% and 2.35 ± 0.21%, respectively (compared with 3.24 ± 0.30% and 3.35 ± 0.21% before the interventions, respectively). The addition of contact tracing to the latter targeted screening scenario reduces the mean prevalence during the 10th year of intervention to 1.48 ± 0.13% (compared with 3.31 ± 0.33% at baseline) in the best-case of testing before treatment and maximal contact-tracing effectiveness (40%). Overall, the most effective scenarios were those for which interventions focused on the high-risk population defined by the number of partners, with contact tracing included. The ICER for targeted screening with contact tracing at 20% and 40% efficiency was $4,634 and $7,219 per QALY gained, respectively (10-year time horizon). Expedited partner therapy did not significantly impact overall chlamydia prevalence and caused overtreatment.

Conclusions

Our study suggests that targeted screening with strengthened contact tracing efforts is the most cost-effective strategy to reduce the prevalence of chlamydia in Hong Kong.

Patterns of sexual behaviour associated with repeated chlamydia testing and infection in men and women: a latent class analysis

BACKGROUND

Adolescents and young adults are at higher risk of acquiring Chlamydia trachomatis infection (chlamydia), so testing is promoted in these populations. Studies have shown that re-testing for chlamydia is common amongst them. We investigated how sexual risk behaviour profiles are associated with repeated testing for chlamydia.

METHODS

We used baseline data from a cohort of 2814 individuals recruited at an urban STI -clinic. We applied latent class (LC) analysis using 9 manifest variables on sexual behaviour and substance use self-reported by the study participants. We fitted ordered logistic regression to investigate the association of LC membership with the outcomes repeated testing during the past 12 months and lifetime repeated testing for chlamydia. Models were fit separately for men and women.

RESULTS

We identified four LCs for men and three LCs for women with increasing gradient of risky sexual behaviour. The two classes with the highest risk among men were associated with lifetime repeated testing for chlamydia: adjOR = 2.26 (95%CI: 1.50-3.40) and adjOR = 3.03 (95%CI: 1.93-4.74) as compared with the class with lowest risk. In women, the class with the highest risk was associated with increased odds of repeated lifetime testing (adjOR =1.85 (95%CI: 1.24-2.76)) and repeated testing during past 12 months (adjOR = 1.72 (95%CI: 1.16-2.54)). An association with chlamydia positive test at the time of the study and during the participant's lifetime was only found in the male highest risk classes.

CONCLUSION

Prevention messages with regard to testing for chlamydia after unprotected sexual contact with new/casual partners seem to reach individuals in highest risk behaviour classes who are more likely to test repeatedly. Further prevention efforts should involve potentially more tailored sex-specific interventions taking into consideration risk behaviour patterns.

Descriptive Epidemiology of Women in the Emergency Department With Gonorrhea and Chlamydial Infection in the United States

Demographic characteristics, risk factors, and clinical variables associated with gonorrhea and chlamydial infection in women being treated in emergency departments (EDs) in the United States are incompletely characterized. We used univariable and multivariable regression analyses on 17,411 encounters from women 18 years and older who presented to EDs in northeast Ohio and were tested for gonorrhea or chlamydial infection. There were 1,360 women (7.8%) who had Chlamydia trachomatis infection and 510 (2.9%) who had Neisseria gonorrhoeae infection. Those infected with C. trachomatis or N. gonorrhoeae were younger (23.8 vs. 29.2 years), unmarried (97.7% vs. 90.1%), Black (93.3% vs. 88.0%), infected with Trichomonas vaginalis (39.9% vs. 27.2%), diagnosed with urinary tract infection (15.7% vs. 10.6%), and treated for gonorrhea and chlamydial infection during the ED visit (31.6% vs. 17.4%) (all ps < .001). Women infected with C. trachomatis or N. gonorrhoeae had more urine white blood cells (WBCs) (23.9 vs. 16.4 cells per high-power field [HPF]) and leukocyte esterase (1.2+ vs. 0.8+) on urinalysis. They had more WBCs (18.5 vs. 12.4 cells/HPF) and odds of having T. vaginalis infection (12.8% vs. 8.2%) on vaginal wet preparation (all ps < .001). Women infected with C. trachomatis were more likely to be younger and not Black; they were less likely to be treated for gonorrhea and chlamydial infection in the ED and to have lower levels of urine WBCs, leukocyte esterase, and blood than those infected with N gonorrhoeae (all ps ≤ .05).

Sexually transmitted infections incidence in young Thai men who have sex with men and transgender women using HIV pre-exposure prophylaxis

BACKGROUND

Sexually transmitted infections are a major public health issue worldwide. HIV pre-exposure prophylaxis (PrEP) use among youth may be associated with increased incidence of sexually transmitted infections (STIs).

OBJECTIVES

To measure the prevalence and incidence of STIs among young men who have sex with men (YMSM) and young transgender women (YTGW) using PrEP.

METHODS

A prospective cohort of 15- to 19-year-old YMSM and YTGW with HIV risk defined as inconsistent condom use and/or multiple sex partners were enrolled. Participants were provided daily oral tenofovir disoproxil fumarate/emtricitabine. STI screening was done at baseline and month 6 for syphilis, urine, and anal swab nucleic acid amplification testing for C. trachomatis (CT) and N. gonorrheaoe (NG).

RESULTS

From March 2018 to June 2019, 200 adolescents (147 MSM and 53 TGW) with a median (IQR) age of 18 years (17-19) were enrolled. STI prevalence was 22.5% (95% CI 16.7-28.3). STI incidence was 25.2 per 100 person-years (95% CI 14.7, 40.3). Factors associated with STI incidence were self-reported >2 sex partners in the past month (unadjusted rate ratio [uRR] 4.6, 95% CI 1.0, 20.6), and moderate PrEP adherence (uRR 7.3, 95% CI 1.6, 32.6).

CONCLUSIONS

STI incidence in YMSM and YTGW PrEP users was high at approximately one in five. Regular screening and treatment of STIs should be implemented in youth HIV prevention packages.

Curable sexually transmitted infections among women with HIV in sub-Saharan Africa

OBJECTIVES

Sexually transmitted infections (STIs) cause significant morbidity among women with HIV and increase HIV transmission. We estimated the prevalence of four STIs among women with HIV in sub-Saharan Africa (SSA) and compared prevalence among women with and without HIV.

DESIGN

Systematic review and meta-analysis.

METHODS

We searched for studies published 1 January 1999 to 19 December 2019 reporting prevalence of gonorrhea, chlamydia, trichomoniasis, or Mycoplasma genitalium among women with HIV in SSA. We excluded studies conducted in high-risk groups (e.g. female sex workers). We extracted data on laboratory-confirmed STIs among women with HIV, and when included, among women without HIV. We estimated pooled prevalence for each STI among women with HIV using inverse variance heterogeneity meta-analysis, compared prevalence to women without HIV, and examined the influences of region, clinical setting, and pregnancy status in subgroup analyses.

RESULTS

We identified 3756 unique records; 67 studies were included in the meta-analysis. Prevalence of gonorrhea, chlamydia, trichomoniasis, and M. genitalium was 3.5, 4, 15.6, and 10.2%, respectively. Chlamydia prevalence was lower in Eastern (2.8%) than in Southern (12.5%) and West/Central (19.1%) Africa combined. Prevalence of chlamydia and trichomoniasis was higher among pregnant (8.1%, 17.6%) than nonpregnant (1.7%, 12.3%) women. All STIs were more prevalent among women with than without HIV (relative risks ranging 1.54-1.89).

CONCLUSION

STIs are common among women with HIV in SSA, and more common among women with than without HIV. Integrated STI and HIV care could substantially impact STI burden among women with HIV, with potential downstream impacts on HIV transmission.

Reported Chlamydia and Gonorrhea Are Decreasing Among Young Black Women: Good News or Bad News? A Narrative Review

ABSTRACT

Since 2010, reported chlamydia and gonorrhea rates decreased among Black women aged 15 to 19 years and were stable for Black women aged 20 to 24 years in the United States. Rates increased for older Black women aged 25 to 39 years and all White women. The Black/White rate ratio decreased across age groups. We examined whether trends in reported rates reflected changing prevalence or changing screening. We analyzed trends in reported chlamydia and gonorrhea rates from 2010 to 2018 among women in the United States aged 15 to 39 years by age and race/ethnicity subgroup, state, and reporting source. Most jurisdictions reported decreased chlamydia and gonorrhea rates among Black teens and increased rates among White teens and older women. Between 2010 and 2018, public clinics reported fewer cases, especially among young Black women, that were not restored by increases elsewhere. We reviewed literature on trends in screening, prevalence, and sequelae. Family planning clinics annual reports showed chlamydia tests among women younger than 25 years decreased by 541,573 tests (-38%) in 2018 compared with 2010 and the number of women visiting sexually transmitted disease clinics had decreased 50% by 2016 compared with 2010. Prevalence of chlamydia in a sentinel population (Job Corps) was unchanged for Black women younger than 25 years and increased for Whites aged 20 to 24 years. Sequelae trends using data from a large all-payer emergency department database were mixed: pelvic inflammatory disease decreased, whereas ectopic pregnancy increased. Decreases in testing at public clinics likely missed diagnoses among young Black women, a group traditionally at highest risk and in need of more testing. Innovative approaches to screening are needed.

An Intervention to Improve Chlamydia and Gonorrhea Testing Among Adolescents in Primary Care

BACKGROUND AND OBJECTIVES

Rates of chlamydia and gonorrhea among adolescents continue to rise. We aimed to evaluate if a universal testing program for chlamydia and gonorrhea improved testing rates in an urban general pediatric clinic and an urban family medicine clinic within a system of federally qualified health care centers and evaluated the feasibility, cost, and logistic challenges of expanding implementation across 28 primary care clinics within a federally qualified health care centers system.

METHODS

A universal testing quality improvement program for male and female patient 14 to 18 years old was implemented in a general pediatrics and family medicine clinic in Denver, Colorado. The intervention was evaluated by using a controlled pre-post quasi-experimental design. The difference in testing rates due to the intervention was assessed by using a difference-in-differences regression model weighted with the inverse probability of treatment.

RESULTS

In total, 15 541 pediatric encounters and 5420 family medicine encounters were included in the analyses. In pediatrics, the unadjusted testing rates increased from 32.0% to 66.7% in the intervention group and from 20.9% to 28.9% in the comparison group. For family medicine, the rates increased from 38.5% to 49.9% in the intervention group and decreased from 26.3% to 24.8% in the comparison group. The intervention resulted in an adjusted increase in screening rates of 25.2% (P < .01) in pediatrics and 11.8% (P < .01) in family medicine. The intervention was well received and cost neutral to the clinic.

CONCLUSIONS

Universal testing for chlamydia and gonorrhea in primary care pediatrics and family medicine is a feasible approach to improving testing rates .

Screening for Chlamydia and Gonorrhea: US Preventive Services Task Force Recommendation Statement

IMPORTANCE

Chlamydia and gonorrhea are among the most common sexually transmitted infections in the US. Infection rates are highest among adolescents and young adults of both sexes. Chlamydial and gonococcal infections in women are usually asymptomatic and may lead to pelvic inflammatory disease and its associated complications. Newborns of pregnant persons with untreated infection may develop neonatal chlamydial pneumonia or gonococcal or chlamydial ophthalmia. Infection in men may lead to urethritis and epididymitis. Both types of infection can increase risk of acquiring or transmitting HIV.

OBJECTIVE

To update its 2014 recommendation, the US Preventive Services Task Force (USPSTF) commissioned a systematic review to evaluate the benefits and harms of screening for chlamydia and gonorrhea in sexually active adolescents and adults, including pregnant persons.

POPULATION

Asymptomatic, sexually active adolescents and adults, including pregnant persons.

EVIDENCE ASSESSMENT

The USPSTF concludes with moderate certainty that screening for chlamydia in all sexually active women 24 years or younger and in women 25 years or older who are at increased risk for infection has moderate net benefit. The USPSTF concludes with moderate certainty that screening for gonorrhea in all sexually active women 24 years or younger and in women 25 years or older who are at increased risk for infection has moderate net benefit. The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening for chlamydia and gonorrhea in men.

RECOMMENDATION

The USPSTF recommends screening for chlamydia in all sexually active women 24 years or younger and in women 25 years or older who are at increased risk for infection. (B recommendation) The USPSTF recommends screening for gonorrhea in all sexually active women 24 years or younger and in women 25 years or older who are at increased risk for infection. (B recommendation) The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening for chlamydia and gonorrhea in men. (I statement).

Prevalence estimates of genital Chlamydia trachomatis infection in Belgium: results from two cross-sectional studies

Background

Chlamydia trachomatis (chlamydia) is the most diagnosed sexually transmitted infection in Belgium. Screening programs focus on young women, due to the implications of chronic asymptomatic infections for reproductive health. Thereby, the frequency of infections in men and older adults is underestimated. This study aimed to estimate the point-prevalence of chlamydia in the broader Belgian population, to inform evidence-based prevention and control strategies.

Methods

We conducted two cross-sectional prevalence studies of chlamydia infection in the population of Belgium aged 16–59 years, 2018–2020. In the CT1 study 12,000 representative individuals were randomly selected from the national register and invited by letter to collect a urine sample at home. The CT2 study used urine samples collected through the Belgian Health Examination Survey. Molecular detection of chlamydia DNA was performed using Xpert^® or Abbott Real-Time CT/NG assays. Weighted estimated prevalence and 95% confidence interval (CI) was calculated per gender and age groups of 16/18–29, 30–44 and 45–59 years, relative to the general Belgian population. Data collected on sociodemographic variables and sexual behavior were used to identify potential risk factors for chlamydia infection through calculation of the odds ratio (OR).

Results

The population-wide weighted estimated prevalence was 1.54% (95% CI 0.78–3) in CT1 and 1.76% (95% CI 0.63–4) in CT2. We observed no statistically significant difference between men and women or age groups. Civil relationship status (OR = 14.1 (95% CI 1.78–112), p < 0.01), sexual intercourse with a casual partner (OR = 6.31 (95% CI 1.66–24.1), p < 0.01) and > 3 sexual partners in the last 12 months (OR = 4.53 (95% CI 1.10–18.6), p = 0.02) were associated with higher relative risk for chlamydia infection.

Conclusion

Nationwide prevalence studies are relevant to assess the distribution of chlamydia and inform public health actions. The overall low prevalence and heterogeneous distribution of chlamydia in the general Belgian population needs to be considered for future strategies and potential harm of testing and treating asymptomatic individuals need to be taken into account. Effective case management should include appropriate treatment of symptomatic patients and partner notification, and prevention strategies should encourage behaviors such as condom use.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06646-y.

Association of Marital Status in the Testing and Treatment of Sexually Transmitted Infections in the Emergency Department

Introduction Sexually transmitted infections (STIs) are frequently tested for and treated in the emergency department (ED). Age, race, and number of sexual partners are known risk factors for STIs. The objective of the current study was to examine marital status as it relates to testing and treating for STIs in the ED. Methods A database of 75,000 ED patient encounters from a single healthcare system in northeast Ohio between April 18, 2014, and March 7, 2017, was examined. All patients in the dataset underwent a urinalysis and urine culture or received STI testing in the ED. We performed Chi-square and multivariable regression analysis to examine the relationships between the patient's marital status and testing and treatment for STIs performed in the ED. Results There were 20,965 patient encounters where STI testing was performed and was analyzed. Patients were 9.1% (N=1,912) married, 86.6% (N=18,149) single, 4.0% (N=837) were neither married nor single, and 0.3% (N=67) with an unknown marital status. There were 7.1% (19/267) and 4.9% (12/267) of tested married men who were infected with gonorrhea and chlamydia, respectively, whereas only 0.4% (6/1,583) and 2.2% (35/1,588) of tested married women were infected with gonorrhea and chlamydia, respectively. Single men and women were both significantly more likely to have a positive test for gonorrhea and chlamydia compared to married men and women, respectively (P<0.001). Married men and women, compared to single men and women, respectively, were more likely to be given antibiotics for gonorrhea and chlamydia in the ED when the infection was present and not be given antibiotics for the infections when testing was negative (P<0.001). Single women (9.1%; 1,291/14,258) were more likely than married women (4.9%; 75/1,534) to have a positive test for trichomonas, but there were no significant differences between married (1.0%; 1/100) and single men (0.7%; 6/893). Conclusion Even when accounting for age and race, marital status can help predict infection with gonorrhea and chlamydia in the ED. The marital status could be considered by clinicians when risk stratifying patients regarding testing and treating for the diseases in the ED. Gonorrhea and chlamydia are much more common in single men and women and much less common in married persons. However, married men tested for gonorrhea and chlamydia were more than twice as likely to test positive for infection than married women. Married men and women were both more likely to be appropriately treated with antibiotics for gonorrhea and chlamydia in the ED (i.e., testing negative for infection and not receiving antibiotics or testing positive and receiving antibiotics) compared to non-married men and women. While trichomonas was more common in single women than married women, the infection was less common in men, and both married men and single men had similar rates of testing positive for the infection.

Gaps in HIV Testing and Treatment Among Female Sex Workers in Lae and Mt. Hagen, Papua New Guinea

We conducted biobehavioral surveys among female sex workers (FSW) in Lae and Mt. Hagen, Papua New Guinea (January-December 2017). Respondent-driven sampling was used to recruit FSW aged ≥ 12 years, who were assigned female sex at birth, who spoke English or Tok Pisin, and who sold or exchanged sex for money, goods, or services in the last 6 months. When adjusted for viral suppression, 48.9% of FSW Lae and 61.9% in Mt. Hagen were aware of their HIV positive status. Of these women, 95.3% in Lae and 98.9% in Mt. Hagen were on antiretroviral therapy, and of these, 83.5% in Lae and 87.0% in Mt. Hagen had suppressed viral load. Renewed efforts are needed to increase HIV testing among FSW and provide support to FSW on treatment in both cities to attain viral suppression.

Chlamydia (lymphogranuloma venereum) peritonitis in a male patient

A 49-year-old man presented with a 1-week history of abdominal pain, distension, diarrhoea and fatigue. CT of the abdomen and pelvis revealed peritonitis with no identifiable cause. Diagnostic laparoscopy was performed, which excluded gastrointestinal perforation. Peritoneal fluid tested positive for Chlamydia trachomatis and rectal swabs were positive for C. trachomatis serovars consistent with lymphogranuloma venereum (LGV). Additional blood tests also revealed a diagnosis of syphilis. This is a rare documented case of LGV peritonitis in a male without associated immunodeficiency. The patient recovered well following laparoscopic washout and a course of appropriate antibiotics.

Estimates of the Prevalence and Incidence of Chlamydia and Gonorrhea Among US Men and Women, 2018

BACKGROUND

The most recent prevalence and incidence estimates for chlamydia and gonorrhea, the 2 most reported sexually transmitted infections in the United States, were for 2008. We present updated estimates of the number of prevalent and incident chlamydial and gonococcal infections for 2018.

METHODS

We estimated chlamydial prevalence directly from the 2015 to 2018 cycles of the National Health and Nutrition Examination Survey and chlamydial incidence using a mathematical model primarily informed by National Health and Nutrition Examination Survey and case report data. Total and antimicrobial-resistant gonococcal prevalence and incidence were estimated using mathematical models primarily informed by case report and Gonococcal Isolate Surveillance Program data. Estimates were calculated for the total population, all women, and all men aged 15 to 39 years, stratified by age group. Primary estimates represent medians and uncertainty intervals represent the 25th (Q1) and 75th (Q3) percentiles of the empirical frequency distributions of prevalence and incidence for each infection.

RESULTS

Among persons aged 15 to 39 years in the United States in 2018, we estimate 2.35 (Q1, 2.20; Q3, 2.51) million prevalent and 3.98 (Q1, 3.77; Q3, 4.22) million incident chlamydial infections, and an estimated 209,000 (Q1, 183,000; Q3, 241,000) prevalent and 1.57 (Q1, 1.44; Q3, 1.72) million incident gonococcal infections. Of all gonococcal infections, there were 107,000 (Q1, 94,000; Q3, 124,000) prevalent and 804,000 (Q1, 738,000; Q3, 883,000) incident infections demonstrating antimicrobial resistance or elevated minimum inhibitory concentrations to selected antibiotics.

CONCLUSIONS

Chlamydia and gonorrhea were very common in the United States in 2018. Estimates show that more than 800,000 newly acquired gonococcal infections in 2018 demonstrated resistance or elevated minimum inhibitory concentrations to currently or previously recommended antibiotics.

Using an agent-based sexual-network model to analyze the impact of mitigation efforts for controlling chlamydia

Chlamydia trachomatis (Ct) is the most reported sexually transmitted infection in the United States, with a major cause of infertility, pelvic inflammatory disease, and ectopic pregnancy among women. Despite decades of screening women for Ct, rates increase among young African Americans (AA). We create and analyze a heterosexual agent-based network model to help understand the spread of Ct. We calibrate the model parameters to agree with survey data showing Ct prevalence of 12% of the women and 10% of the men in the 15-25 year-old AA in New Orleans, Louisiana. Our model accounts for both long-term and casual partnerships. The network captures the assortative mixing of individuals by preserving the joint-degree distributions observed in the data. We compare the effectiveness of intervention strategies based on randomly screening men, notifying partners of infected people, which includes partner treatment, partner screening, and rescreening for infection. We compare the difference between treating partners of an infected person both with and without testing them. We observe that although increased Ct screening, rescreening, and treating most of the partners of infected people will reduce the prevalence, these mitigations alone are not sufficient to control the epidemic. The current practice is to treat the partners of an infected individual without first testing them for infection. The model predicts that if a sufficient number of the partners of all infected people are tested and treated, then there is a threshold condition where the epidemic can be mitigated. This threshold results from the expanded treatment network created by treating an individual's infected partners' partners. Although these conclusions can help design future Ct mitigation studies, we caution the reader that these conclusions are for the mathematical model, not the real world, and are contingent on the validity of the model assumptions.

Why Are Rates of Reported Chlamydia Changing in the United States? Insights From the National Job Training Program

BACKGROUND

In 2010 to 2017, rates of reported chlamydia decreased among young Black women but increased for White women and all men. Because chlamydia case rates can be influenced by changes in prevalence, screening, and other factors, we compared chlamydia prevalence trends in a sentinel population with national case rate trends to understand potential drivers of case rate trends.

METHODS

Chlamydia prevalence was calculated annually among 16- to 24-year-old entrants to the National Job Training Program (NJTP) in 2010 to 2017. An expectation-maximization-based maximum likelihood approach was used to adjust for misclassification due to imperfect test sensitivity and specificity. Models were stratified by sex, age, and race/ethnicity. A statistically significant trend in prevalence was defined as nonoverlapping 95% confidence intervals comparing 2010 and 2017. Trends in chlamydia prevalence were compared with trends in case rates using percentage change over time; relative changes ≥10% were considered meaningful.

RESULTS

Among NJTP entrants in 2010 to 2017, chlamydia prevalence was stable for all Black women, whereas case rates decreased for adolescents (-12%) and were stable for 20- to 24-year-olds (-4%). Among adolescent White women, prevalence was stable, whereas case rates increased (+30%). For White women aged 20 to 24 years, prevalence increased +62% and case rates increased +43%. Trends in prevalence differed from trends in case rates for all subgroups of men.

CONCLUSIONS

Prevalence trends in this sentinel population differed from national case rate trends for Black women, White women, and men, suggesting potential decreased screening among Black women aged 16 to 19 years, increased prevalence among White women aged 20 to 24 years, and increased screening among men.

High Prevalence of Chlamydia and Gonorrhea and the Need for Sexually Transmitted Infection Testing Among Men Who Have Sex With Men and Transgender Women in Papua New Guinea

BACKGROUND

Papua New Guinea has among the highest prevalence of sexually transmitted infections in the world but no estimates of Chlamydia trachomatis, Neisseria gonorrhoeae, or hepatitis B virus (HBV) are available among men who have sex with men (MSM) or transgender women (TGW).

METHODS

We conducted respondent-driven sampling surveys among MSM and TGW in Port Moresby, Lae, and Mt Hagen (2016-2017) to characterize the prevalence of these infections. Eligibility criteria were as follows: aged ≥12 years, born male, could speak English or Tok Pisin, and had oral or anal sex with another person born male in the past 6 months. Participants were surveyed face-to-face and offered testing for anorectal and genital chlamydia and gonorrhea, syphilis, HIV, and HBV. All results are respondent-driven sampling weighted.

RESULTS

We enrolled 400 participants in Port Moresby, 352 in Lae, and 111 in Mt Hagen. Chlamydia prevalence rates in the 3 cities regardless of anatomical site were 19.9%, 19.2%, and 24.3%, respectively. Gonorrhea prevalence rates regardless of anatomical site were 10.3%, 9.4%, and 9.6%, respectively. Hepatitis B virus prevalence rates were 11.7%, 13.8%, and 13.6%, respectively. In multivariable analysis, syphilis was associated with having either chlamydia or gonorrhea in Port Moresby (adjusted odds ratio, 4.0; 95% confidence interval, 2.0-7.9) and Lae (adjusted odds ratio, 2.4; 95% confidence interval, 1.2-5.0).

CONCLUSIONS

There is a large unmet need among MSM and TGW in Papua New Guinea for chlamydia and gonorrhea detection and treatment. The high prevalence of HBV reinforces the importance of ensuring introduction and scale-up of HBV treatment and immunization. Urgent efforts are needed to introduce laboratory-based diagnosis for chlamydia and gonorrhea to ensure these populations have access to much needed treatment services.

Eukaryotic SNARE VAMP3 Dynamically Interacts with Multiple Chlamydial Inclusion Membrane Proteins

Chlamydia trachomatis, an obligate intracellular pathogen, undergoes a biphasic developmental cycle within a membrane-bound vacuole called the chlamydial inclusion. To facilitate interactions with the host cell, Chlamydia modifies the inclusion membrane with type III secreted proteins, called Incs.

Chlamydia trachomatis, an obligate intracellular pathogen, undergoes a biphasic developmental cycle within a membrane-bound vacuole called the chlamydial inclusion. To facilitate interactions with the host cell, Chlamydia modifies the inclusion membrane with type III secreted proteins, called Incs. As with all chlamydial proteins, Incs are temporally expressed, modifying the chlamydial inclusion during the early and mid-developmental cycle. VAMP3 and VAMP4 are eukaryotic SNARE proteins that mediate membrane fusion and are recruited to the inclusion to facilitate inclusion expansion. Their recruitment requires de novo chlamydial protein synthesis during the mid-developmental cycle. Thus, we hypothesize that VAMP3 and VAMP4 are recruited by Incs. In chlamydia-infected cells, identifying Inc binding partners for SNARE proteins specifically has been elusive. To date, most studies examining chlamydial Inc and eukaryotic proteins have benefitted from stable interacting partners or a robust interaction at a specific time postinfection. While these types of interactions are the predominant class that have been identified, they are likely the exception to chlamydia-host interactions. Therefore, we applied two separate but complementary experimental systems to identify candidate chlamydial Inc binding partners for VAMPs. Based on these results, we created transformed strains of C. trachomatis serovar L2 to inducibly express a candidate Inc-FLAG protein. In chlamydia-infected cells, we found that five Incs temporally and transiently interact with VAMP3. Further, loss of incA or ct813 expression altered VAMP3 localization to the inclusion. For the first time, our studies demonstrate the transient nature of certain host protein-Inc interactions that contribute to the chlamydial developmental cycle.

Do we need to worry about sexually transmissible infections (STIs) in older women in Australia? An investigation of STI trends between 2000 and 2018

Background This study examined trends in chlamydia, gonorrhoea and syphilis diagnosis, and chlamydia testing and positivity, among older women in Australia between 2000 and 2018.

METHODS

Using national notifiable disease data and Medicare data, diagnosis rates were calculated for each sexually transmissible infection (STI), as well as testing and positivity rates for chlamydia. Data were compared between two older groups (55-64 and 65-74 years) and two younger groups (15-24 and 25-34 years). Poisson regression examined trends for 2000-18 and 2014-18 separately.

RESULTS

Rates for all STIs increased across all age groups and were highest in the two youngest age groups. From 2014 to 2018, chlamydia rates increased the most among those aged 55-64 years [incidence rate ratio (IRR) = 1.06; 95%CI: 1.02-1.10] and declined in those aged 15-24 years (IRR = 0.99; 95%CI: 0.99-0.99). Gonorrhoea rates increased the most among those aged 65-74 years (IRR = 1.47; 95%CI: 1.23-1.77) and least in those aged 15-24 years (IRR = 1.12; 95%CI: 1.10-1.13). Syphilis rates increased the most among those aged 55-64 years (IRR = 1.58; 95%CI: 1.25-1.99) and least in those aged 15-24 years (IRR = 1.29; 95%CI: 1.23-1.35). Chlamydia test positivity declined among younger women but remained stable in older women.

CONCLUSIONS

In general, STIs are increasing among older women in Australia at a faster rate than among younger women. Although the greatest burden is among younger women, STIs need to be considered and monitored among older women.

Sequence variation and immunogenicity of the Mycoplasma genitalium MgpB and MgpC adherence proteins during persistent infection of men with non-gonococcal urethritis

Mycoplasma genitalium is a sexually transmitted bacterial pathogen that infects men and women. Antigenic variation of MgpB and MgpC, the immunodominant adherence proteins of M. genitalium, is thought to contribute to immune evasion and chronic infection. We investigated the evolution of mgpB and mgpC sequences in men with non-gonococcal urethritis persistently infected with M. genitalium, including two men with anti-M. genitalium antibodies at enrollment and two that developed antibodies during follow-up. Each of the four patients was persistently infected with a different strain type and each patient produced antibodies targeting MgpB and MgpC. Amino acid sequence evolution in the variable regions of MgpB and MgpC occurred in all four patients with changes observed in single and multiple variable regions over time. Using the available crystal structure of MgpC of the G37 type strain we found that predicted conformational B cell epitopes localize predominantly to the variable region of MgpC, amino acids that changed during patient infection lie in these epitopes, and variant amino acids are in close proximity to the conserved sialic acid binding pocket. These findings support the hypothesis that sequence variation functions to avoid specific antibodies thereby contributing to persistence in the genital tract.

The frontiers of addressing antibiotic resistance in Neisseria gonorrhoeae

The sexually transmitted infection gonorrhea, caused by the Gram-negative bacterium Neisseria gonorrhoeae, can cause urethritis, cervicitis, and systemic disease, among other manifestations. N. gonorrhoeae has rapidly rising incidence along with increasing levels of antibiotic resistance to a broad range of drugs including first-line treatments. The rise in resistance has led to fears of untreatable gonorrhea causing substantial disease globally. In this review, we will describe multiple approaches being undertaken to slow and control this spread of resistance. First, a number of old drugs have been repurposed and new drugs are being developed with activity against Neisseria gonorrhoeae. Second, vaccine development, long an important goal, is advancing. Third, new diagnostics promise rapid detection of antibiotic resistance and a shift from empiric to tailored treatment. The deployment of these new tools for addressing the challenge of antibiotic resistance will require careful consideration to provide optimal care for all patients while extending the lifespan of treatment regimens.

Global epidemiology of Neisseria gonorrhoeae in infertile populations: systematic review, meta-analysis and metaregression

Objective

To provide an in-depth systematic assessment of the global epidemiology of gonorrhoea infection in infertile populations.

Methods

A systematic literature review was conducted up to 29 April 2019 on international databases and WHO regional databases, and reported following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. All prevalence measures of gonorrhoea infection among infertile populations, based on primary data, qualified for inclusion. Infertile populations were broadly defined to encompass women/men undergoing infertility evaluation or treatment (infertility clinic attendees and partners). Pooled mean prevalence by relevant strata was estimated using random-effects meta-analysis. Associations with prevalence and sources of heterogeneity were explored using metaregression. Risk of bias was assessed using four quality domains.

Findings

A total of 147 gonorrhoea prevalence studies were identified from 56 countries. The pooled mean prevalence of current gonorrhoea infection was estimated globally at 2.2% (95% CI 1.3% to 3.2%), with the highest prevalence in Africa at 5.0% (95% CI 1.9% to 9.3%). The mean prevalence was higher for populations with tubal factor infertility (3.6%, 95% CI 0.9%–7.7%) and mixed cause and unexplained infertility (3.6%, 95% CI 0.0% to 11.6%) compared with other diagnoses, such as ovarian and non-tubal infertility (0.1%, 95% CI 0.0% to 0.8%), and for secondary (2.5%, 95% CI 0.2% to 6.5%) compared with primary (0.5%, 95% CI 0.0% to 1.7%) infertility. Metaregression identified evidence of variations in prevalence by region and by infertility diagnosis, higher prevalence in women than men and a small-study effect. There was a trend of declining prevalence by about 3% per year over the last four decades (OR=0.97, 95% CI 0.95 to 0.99).

Conclusions

Gonorrhoea prevalence in infertile populations is several folds higher than that in the general population, with even higher prevalence in women with tubal factor infertility and in individuals with secondary infertility. These findings support the potential role of gonorrhoea in infertility and suggest that some infertility is possibly preventable by controlling gonorrhoea transmission.

PROSPERO registration number

CRD42018102934.

Modelling the impact of screening for chlamydia and gonorrhoea in youth and other high-prevalence groups in a resource-limited setting

OBJECTIVES

Modelling the potential impact of screening for chlamydia and gonorrhoea in youth and other populations in a resource-limited setting.

METHODS

We extended an agent-based model of heterosexual chlamydia and gonorrhoea transmission in South Africa to investigate the impact of screening strategies in key populations including youth, patients in HIV care, pregnant women and female sex workers (FSWs). Additionally, we compared the modelled impact of a standardised screening programme to results obtained from other published mathematical models of chlamydia screening.

RESULTS

All strategies resulted in reductions in general and targeted population chlamydia and gonorrhoea transmission. Opportunistic screening of patients in youth and HIV care was shown to be the most effective, and FSW screening was shown to be the most efficient strategy. Differences between models could be attributed to differences in the modelled heterogeneity in sexual behaviour as well as differences in assumptions about immunity following chlamydia recovery.

CONCLUSIONS

Taking modelling assumptions into account, opportunistic chlamydia and gonorrhoea screening of youth and those in HIV care represents a viable intervention for reducing sexually transmitted infections in the South African population.

Toll-Like Receptor 3 Deficiency Leads to Altered Immune Responses to Chlamydia trachomatis Infection in Human Oviduct Epithelial Cells

Reproductive tract pathology caused by Chlamydia trachomatis infection is an important global cause of human infertility. To better understand the mechanisms associated with Chlamydia-induced genital tract pathogenesis in humans, we used CRISPR genome editing to disrupt Toll-like receptor 3 (TLR3) function in the human oviduct epithelial (hOE) cell line OE-E6/E7 in order to investigate the possible role(s) of TLR3 signaling in the immune response to Chlamydia Disruption of TLR3 function in these cells significantly diminished the Chlamydia-induced synthesis of several inflammation biomarkers, including interferon beta (IFN-β), interleukin-6 (IL-6), interleukin-6 receptor alpha (IL-6Rα), soluble interleukin-6 receptor beta (sIL-6Rβ, or gp130), IL-8, IL-20, IL-26, IL-34, soluble tumor necrosis factor receptor 1 (sTNF-R1), tumor necrosis factor ligand superfamily member 13B (TNFSF13B), matrix metalloproteinase 1 (MMP-1), MMP-2, and MMP-3. In contrast, the Chlamydia-induced synthesis of CCL5, IL-29 (IFN-λ1), and IL-28A (IFN-λ2) was significantly increased in TLR3-deficient hOE cells compared to their wild-type counterparts. Our results indicate a role for TLR3 signaling in limiting the genital tract fibrosis, scarring, and chronic inflammation often associated with human chlamydial disease. Interestingly, we saw that Chlamydia infection induced the production of biomarkers associated with persistence, tumor metastasis, and autoimmunity, such as soluble CD163 (sCD163), chitinase-3-like protein 1, osteopontin, and pentraxin-3, in hOE cells; however, their expression levels were significantly dysregulated in TLR3-deficient hOE cells. Finally, we demonstrate using hOE cells that TLR3 deficiency resulted in an increased amount of chlamydial lipopolysaccharide (LPS) within Chlamydia inclusions, which is suggestive that TLR3 deficiency leads to enhanced chlamydial replication and possibly increased genital tract pathogenesis during human infection.

Multi-locus sequence analysis reveals a novel sequence type of Chlamydia trachomatis in Saratov Region, Russia

Chlamydia trachomatis is the causative agent of a variety of chlamydial infections in humans with a predominantly (up to 80%) asymptomatic course of disease. In this study, a potentially novel C. trachomatis sequence type (ST) was detected in an asymptomatic man who has sex with a man among the nine STs revealed in urogenital swabs from individuals with chlamydia (n = 18). Phylogenetically this ST270 clustered separately as a single clade to an ST13-founded group of C. trachomatis strains and differed from the latter by a single allele, hflX. This finding emphasizes the importance of careful investigation of individuals with asymptomatic chlamydia infections.

Modelling the in-host dynamics of Neisseria gonorrhoeae infection

The bacterial species Neisseria gonorrhoeae (NG) has evolved to replicate effectively and exclusively in human epithelia, with its survival dependent on complex interactions between bacteria, host cells and antimicrobial agents. A better understanding of these interactions is needed to inform development of new approaches to gonorrhoea treatment and prevention but empirical studies have proven difficult, suggesting a role for mathematical modelling. Here, we describe an in-host model of progression of untreated male symptomatic urethral infection, including NG growth and interactions with epithelial cells and neutrophils, informed by in vivo and in vitro studies. The model reproduces key observations on bacterial load and clearance and we use multivariate sensitivity analysis to refine plausible ranges for model parameters. Model variants are also shown to describe mouse infection dynamics with altered parameter ranges that correspond to observed differences between human and mouse infection. Our results highlight the importance of NG internalisation, particularly within neutrophils, in sustaining infection in the human model, with ∼80% of the total NG population internalised from day 25 on. This new mechanistic model of in-host NG infection dynamics should also provide a platform for future studies relating to antimicrobial treatment and resistance and infection at other anatomical sites.

Gonorrhoea and chlamydia diagnosis as an entry point for HIV pre-exposure prophylaxis: a modelling study

OBJECTIVES

Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) increase the risk of HIV transmission among men who have sex with men (MSM). Diagnosis of NG/CT may provide an efficient entry point for prevention of HIV through the delivery of pre-exposure prophylaxis (PrEP); however, the additional population-level impact of targeting PrEP to MSM diagnosed with NG/CT is unknown.

DESIGN

An agent-based simulation model of NG/CT and HIV cocirculation among MSM calibrated against census data, disease surveillance reports and the US National HIV Behavioral Surveillance study.

SETTING

Baltimore City, Maryland, USA.

INTERVENTIONS

PrEP implementation was modelled under three alternative scenarios: (1) PrEP delivery at NG/CT diagnosis (targeted delivery), (2) PrEP evaluation at NG/CT screening/testing and (3) PrEP evaluation in the general community (untargeted).

MAIN OUTCOME

The projected incidence of HIV after 20 years of PrEP delivery under two alternatives: when equal numbers of MSM are (1) screened for PrEP or (2) receive PrEP in each year.

RESULTS

Assuming 60% uptake and 60% adherence, targeting PrEP to MSM diagnosed with NG/CT could reduce HIV incidence among MSM in Baltimore City by 12.4% (95% uncertainty range (UR) 10.3% to 14.4%) in 20 years, relative to no PrEP. Expanding the coverage of NG/CT screening (such that individuals experience a 50% annual probability of NG/CT screening and evaluation for PrEP on NG/CT diagnosis) can further increase the impact of targeted PrEP to generate a 22.0% (95% UR 20.1% to 23.9%) reduction in HIV incidence within 20 years. When compared with alternative implementation scenarios, PrEP evaluation at NG/CT diagnosis increased impact of PrEP on HIV incidence by 1.5(95% UR 1.1 to 1.9) times relative to a scenario in which PrEP evaluation happened at the time of NG/CT screening/testing and by 1.6 (95% UR 1.2 to 2.2) times relative to evaluating random MSM from the community.

CONCLUSIONS

Targeting MSM infected with NG/CT increases the efficiency and effectiveness of PrEP delivery. If high levels of sexually transmitted infection screening can be achieved at the community level, NG/CT diagnosis may be a highly effective entry point for PrEP initialisation.

A dynamic power-law sexual network model of gonorrhoea outbreaks

Human networks of sexual contacts are dynamic by nature, with partnerships forming and breaking continuously over time. Sexual behaviours are also highly heterogeneous, so that the number of partners reported by individuals over a given period of time is typically distributed as a power-law. Both the dynamism and heterogeneity of sexual partnerships are likely to have an effect in the patterns of spread of sexually transmitted diseases. To represent these two fundamental properties of sexual networks, we developed a stochastic process of dynamic partnership formation and dissolution, which results in power-law numbers of partners over time. Model parameters can be set to produce realistic conditions in terms of the exponent of the power-law distribution, of the number of individuals without relationships and of the average duration of relationships. Using an outbreak of antibiotic resistant gonorrhoea amongst men have sex with men as a case study, we show that our realistic dynamic network exhibits different properties compared to the frequently used static networks or homogeneous mixing models. We also consider an approximation to our dynamic network model in terms of a much simpler branching process. We estimate the parameters of the generation time distribution and offspring distribution which can be used for example in the context of outbreak reconstruction based on genomic data. Finally, we investigate the impact of a range of interventions against gonorrhoea, including increased condom use, more frequent screening and immunisation, concluding that the latter shows great promise to reduce the burden of gonorrhoea, even if the vaccine was only partially effective or applied to only a random subset of the population.

Impacts of Federal Prevention Funding on Reported Gonorrhea and Chlamydia Rates

INTRODUCTION

The Centers for Disease Control and Prevention allocates funds annually to jurisdictions nationwide for sexually transmitted infection prevention activities. The objective of this study was to assess the effectiveness of federal sexually transmitted infection prevention funding for reducing rates of reported sexually transmitted infections.

METHODS

In 2017-2018, finite distributed lag regression models were estimated to assess the impact of sexually transmitted infection prevention funding (in 2016 dollars per capita) on reported chlamydia rates from 2000 to 2016 and reported gonorrhea rates from 1981 to 2016. Including lagged funding measures allowed for assessing the impact of funding over time. Controls for state-level socioeconomic factors, such as poverty rates, were included.

RESULTS

Results from the main model indicate that a 1% increase in annual funding would cumulatively decrease chlamydia and gonorrhea rates by 0.17% (p<0.10) and 0.33% (p<0.05), respectively. Results were similar when stratified by sex, with significant decreases in rates of reported chlamydia and gonorrhea in males of 0.33% and 0.34% (both p<0.05) respectively, and in rates of reported gonorrhea in females of 0.32% (p<0.05). The results were generally consistent across alternative model specifications and other robustness tests.

CONCLUSIONS

The significant inverse associations between federal sexually transmitted infection prevention funding and rates of reported chlamydia and gonorrhea suggest that federally funded sexually transmitted infection prevention activities have a discernable effect on reducing the burden of sexually transmitted infections. The reported sexually transmitted infection rate in a given year depends more on prevention funding in previous years than on prevention funding in the current year, demonstrating the importance of accounting for lagged funding effects.

Seventy Years of Chlamydia Vaccine Research - Limitations of the Past and Directions for the Future

Chlamydia is a major bacterial pathogen that infects humans, as well as a wide range of animals, including marsupials, birds, cats, pigs, cattle, and sheep. Antibiotics are the only treatment currently available, however, with high rates of re-infection, there is mounting pressure to develop Chlamydia vaccines. In this review, we analyzed how Chlamydia vaccine trials have developed over the past 70 years and identified where future trials need to be focused. There has been a strong bias toward studies targeting C. muridarum and C. trachomatis within mice and a lack of studies matching chlamydial species to their end target host. Even though a large number of specific antigenic targets have been studied, the results from whole-cell vaccine targets show slightly more promising results overall. There has also been a strong bias toward systemic vaccine delivery systems, despite the finding that mucosal delivery systems have shown more promising outcomes. However, the only successful vaccines with matched chlamydial species/infecting host are based on systemic vaccine delivery methods. We highlight the extensive work done with mouse model trials and indicate that whole cell antigenic targets are capable of inducing an effective response, protecting from disease and reducing shedding rates. However, replication of these results using antigen preparations more conducive to commercial vaccine production has proven difficult. To date, the Major Outer Membrane Protein (MOMP) has emerged as the most suitable substitute for whole cell targets and its delivery as a combined systemic and mucosal vaccine is most effective. Finally, although mouse model trials are useful, differences between hosts and infecting chlamydial strains are preventing vaccine formulations from mouse models to be translated into larger animals or intended hosts.

How Good Is Your Rule of Thumb? Validating Male-to-Female Case Ratio as a Proxy for Men Who Have Sex With Men Involvement in N. gonorrhoeae Incidence at the County Level

BACKGROUND

Lacking information on men who have sex with men (MSM) for most reported cases, sexually transmitted disease (STD) programs in the United States have used crude measures such as male-to-female case ratios (MFCR) as a rule of thumb to gauge MSM involvement at the local level, primarily with respect to syphilis cases in the past. Suitability of this measure for gonorrhea incidence has not previously been investigated.

METHODS

A random sample of gonorrhea cases reported from January 2010 through June 2013 were interviewed in selected counties participating in the STD Surveillance Network to obtain gender of sex partners and history of transactional sex. Weighted estimates of proportion of cases among MSM and proportion reporting transactional sex were developed; correlation between MFCR and proportion MSM was assessed.

RESULTS

Male-to-female case ratio ranged from 0.66 to 8.7, and the proportion of cases occurring among MSM varied from 2.5% to 62.3%. The MFCR was strongly correlated with proportion of cases among MSM after controlling for transactional sex (Pearson partial r = 0.754, P < 0.0001).

CONCLUSIONS

Male-to-female case ratio for gonorrhea at the county level is a reliable proxy measure indicating MSM involvement in gonorrhea case incidence and should be used by STD programs to tailor their programmatic mix to include MSM-specific interventions.

Systematic evaluation of the population-level effects of alternative treatment strategies on the basic reproduction number

An approach to estimate the influence of the treatment-type controls on the basic reproduction number, R₀, is proposed and elaborated. The presented approach allows one to estimate the effect of a given treatment strategy or to compare a number of different treatment strategies on the basic reproduction number. All our results are valid for sufficiently small values of the control. However, in many cases it is possible to extend this analysis to larger values of the control as was illustrated by examples.

Maternal genitourinary infections and risk of birth defects in the National Birth Defects Prevention Study

BACKGROUND

Genitourinary infections (GUIs) are common among sexually active women. Yet, little is known about the risk of birth defects associated with GUIs.

METHODS

Using data from the National Birth Defects Prevention Study, a multisite, population-based, case-control study, we assessed self-reported maternal GUIs in the month before through the third month of pregnancy (periconception) from 29,316 birth defect cases and 11,545 unaffected controls. We calculated odds ratios (ORs) and 95% confidence intervals to estimate the risk of 52 major structural birth defects associated with GUIs. We also calculated risk of birth defects associated with each type of GUI: urinary tract infection (UTI) and sexually transmitted infection (STI).

RESULTS

In our analysis, 10% (n = 2,972) of case and 9% (n = 1,014) of control mothers reported a periconceptional GUI. A GUI was significantly associated with 11 of the 52 birth defects examined (ORs ranging from 1.19 to 2.26): encephalocele, cataracts, cleft lip, esophageal atresia, duodenal atresia/stenosis, small intestinal atresia/stenosis, colonic atresia/stenosis, transverse limb deficiency, conoventricular septal defect, atrioventricular septal defect, and secundum atrial septal defect. A periconceptional UTI was significantly associated with nine birth defects (ORs from 1.21 to 2.48), and periconceptional STI was significantly associated with four birth defects (ORs ranging from 1.63 to 3.72).

CONCLUSIONS

While misclassification of GUIs in our analysis is likely, our findings suggest GUIs during the periconceptional period may increase the risk for specific birth defects.

Chlamydia pecorum gastrointestinal tract infection associations with urogenital tract infections in the koala (Phascolarctos cinereus)

Background

Chlamydia infects multiple sites within hosts, including the gastrointestinal tract (GIT). In certain hosts, gastrointestinal infection is linked to treatment avoidance and self-infection at disease susceptible sites. GIT C. pecorum has been detected in livestock and koalas, however GIT prevalence rates within the koala are yet to be established.

Methods

Paired conjunctival, urogenital and rectal samples from 33 koalas were screened for C. pecorum and C. pecorum plasmid using 16S rRNA and CDS5-specific quantitative PCR assays, respectively. Amplicon sequencing of 359 bp ompA fragment was used to identify site-specific genotypes.

Results

The overall C. pecorum prevalence collectively (healthy and clinically diseased koalas) was 51.5%, 57.6% and 42.4% in urogenital, conjunctival and gastrointestinal sites, respectively. Concurrent urogenital and rectal Chlamydia was identified in 14 koalas, with no cases of GIT only Chlamydia shedding. The ompA genotype G dominated the GIT positive samples, and genotypes A and E’ were dominant in urogenital tract (UGT) positive samples. Increases in C. pecorum plasmid per C. pecorum load (detected by PCR) showed clustering in the clinically diseased koala group (as assessed by scatter plot analysis). There was also a low correlation between plasmid positivity and C. pecorum infected animals at any site, with a prevalence of 47% UGT, 36% rectum and 40% faecal pellet.

Conclusions

GIT C. pecorum PCR positivity suggests that koala GIT C. pecorum infections are common and occur regularly in animals with concurrent genital tract infections. GIT dominant genotypes were identified and do not appear to be related to plasmid positivity. Preliminary results indicated a possible association between C. pecorum plasmid load and clinical UGT disease.

Adult gonorrhea, chlamydia and syphilis prevalence, incidence, treatment and syndromic case reporting in South Africa: Estimates using the Spectrum-STI model, 1990-2017

OBJECTIVES

To estimate trends in prevalence and incidence of syphilis, gonorrhea and chlamydia in adult men and women in South Africa.

METHODS

The Spectrum-STI tool estimated trends in prevalence and incidence of active syphilis, gonorrhea and chlamydia, fitting South African prevalence data. Results were used, alongside programmatic surveillance data, to estimate trends in incident gonorrhea cases resistant to first-line treatment, and the reporting gap of symptomatic male gonorrhea and chlamydia cases treated but not reported as cases of urethritis syndrome.

RESULTS

In 2017 adult (15-49 years) the estimated female and male prevalences for syphilis were 0.50% (95% CI: 0.32-0.80%) and 0.97% (0.19-2.28%), for gonorrhea 6.6% (3.8-10.8%) and 3.5% (1.7-6.1%), and for chlamydia 14.7% (9.9-21%) and 6.0% (3.8-10.4%), respectively. Between 1990 and 2017 the estimated prevalence of syphilis declined steadily in women and men, probably in part reflecting improved treatment coverage. For gonorrhea and chlamydia, estimated prevalence and incidence showed no consistent time trend in either women or men. Despite growing annual numbers of gonorrhea cases - reflecting population growth - the estimated number of first line treatment-resistant gonorrhea cases did not increase between 2008 and 2017, owing to changes in first-line antimicrobial treatment regimens for gonorrhea in 2008 and 2014/5. Case reporting completeness among treated male urethritis syndrome episodes was estimated at 10-28% in 2017.

CONCLUSION

South Africa continues to suffer a high STI burden. Improvements in access and quality of maternal, STI and HIV health care services likely contributed to the decline in syphilis prevalence. The lack of any decline in gonorrhea and chlamydia prevalence highlights the need to enhance STI services beyond clinic-based syndromic case management, to reinvigorate primary STI and HIV prevention and, especially for women, to screen for asymptomatic infections.

High chlamydia and gonorrhoea repeat positivity in remote Aboriginal communities 2009-2011: longitudinal analysis of testing for re-infection at 3 months suggests the need for more frequent screening

Background Extremely high rates of diagnosis of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) have been recorded in remote communities across northern and central Australia. Re-testing at 3 months, after treatment administered, of CT or NG is recommended to detect repeat infections and prevent morbidity and ongoing transmission.

METHODS

Baseline CT and NG laboratory data (2009-2010) from 65 remote health services participating in a cluster randomised trial was used to calculate the proportion of individuals re-tested after an initial CT or NG diagnosis at <2 months (not recommended), 2-4 months (recommended) and 5-12 months and the proportion with repeat positivity on re-test. To assess if there were difference in re-testing and repeat positivity by age group and sex, t-tests were used.

RESULTS

There was a total of 2054 people diagnosed with CT and/or NG in the study period; 14.9% were re-tested at 2-4 months, 26.9% at 5-12 months, a total of 41.8% overall. Re-testing was higher in females than in males in both the 2-4-month (16.9% v. 11.5%, P<0.01) and 5-12-month (28.9% v. 23.5%, P=0.01) periods. Women aged 25-29 years had a significantly higher level of re-testing 5-12 months post-diagnosis than females aged 16-19 years (39.8% v. 25.4%, P<0.01). There was a total of 858 people re-tested at 2-12 months and repeat positivity was 26.7%. There was higher repeat NG positivity than repeat CT positivity (28.8% v. 18.1%, P<0.01).

CONCLUSIONS

Just under half the individuals diagnosed with CT or NG were re-tested at 2-12 months post-diagnosis; however, only 15% were re-tested in the recommended time period of 2-4 months. The higher NG repeat positivity compared with CT is important, as repeat NG infections have been associated with higher risk of pelvic inflammatory disease-related hospitalisation. Findings have implications for clinical practice in remote community settings and will inform ongoing sexual health quality improvement programs in remote community clinics.

Detection of Chlamydia trachomatis mRNA using digital PCR as a more accurate marker of viable organism

Spontaneous resolution of urogenital Chlamydia trachomatis (CT) without treatment has previously been described, but a limitation of these reports is that DNA or RNA-based amplification tests used do not differentiate between viable infection and non-viable DNA. We modified a previously published CT mRNA detection (omp2) method to differentiate between viable infection and non-viable DNA in a sample of CT DNA PCR positive women. We modified a CT mRNA detection (omp2) method from reverse transcriptase qPCR (RTqPCR) to digital PCR (dPCR) and evaluated it in samples from CT DNA positive women. Firstly, CT infected McCoy B cells treated with azithromycin in vitro identified detectable mRNA levels disappeared <2 days, while DNA persisted up to 6 days. We used 55 self-collected vaginal swabs from a cohort of women diagnosed as DNA positive for chlamydia obtained pre- and 7 days of post-azithromycin treatment. Concordance with DNA results was higher for dPCR than RTqPCR (74.5% versus 65.5%). At visit 1, there was a strong linear relationship between DNA and mRNA (r = 0.9, p < 0.000); 24 samples had both mRNA and DNA detected (82.8%) and 5 had only DNA detected with a potential false positive proportion of 17.2% (95%CI: 5.8, 35.8). At visit 2, there was poor correlation between DNA and mRNA (r = 0.14, p = 0.55); eight specimens had only DNA detected (42.1%; 95%CI: 20.25, 66.50) and one had mRNA detected. DNA detection methods alone may detect non-viable DNA. Consideration should be given to further develop mRNA assays as ancillary tests to improve detection of viable chlamydia.

Chlamydia muridarum Genital and Gastrointestinal Infection Tropism Is Mediated by Distinct Chromosomal Factors

Some members of the genus Chlamydia, including the human pathogen Chlamydia trachomatis, infect multiple tissues, including the genital and gastrointestinal (GI) tracts. However, it is unknown if bacterial targeting to these sites is mediated by multifunctional or distinct chlamydial factors. We previously showed that disruption of individual large clostridial toxin homologs encoded within the Chlamydia muridarum plasticity zone were not critical for murine genital tract infection. Here, we assessed whether cytotoxin genes contribute to C. muridarum GI tropism. Infectivity and shedding of wild-type (WT) C. muridarum and three mutants containing nonsense mutations in different cytotoxin genes, tc0437, tc0438, and tc0439, were compared in mouse genital and GI infection models. One mutant, which had a nonsense mutation in tc0439, was highly attenuated for GI infection and had a GI 50% infectious dose (ID50) that was 1,000 times greater than that of the WT. GI inoculation with this mutant failed to elicit anti-chlamydial antibodies or to protect against subsequent genital tract infection. Genome sequencing of the tc0439 mutant revealed additional chromosomal mutations, and phenotyping of additional mutants suggested that the GI attenuation might be linked to a nonsense mutation in tc0600 The molecular mechanism underlying this dramatic difference in tissue-tropic virulence is not fully understood. However, isolation of these mutants demonstrates that distinct chlamydial chromosomal factors mediate chlamydial tissue tropism and provides a basis for vaccine initiatives to isolate chlamydia strains that are attenuated for genital infection but retain the ability to colonize the GI tract and elicit protective immune responses.

Diagnostic accuracy of a prototype rapid chlamydia and gonorrhoea recombinase polymerase amplification assay: a multicentre cross-sectional preclinical evaluation

Objectives

Rapid and accurate sexually transmitted infection diagnosis can reduce onward transmission and improve treatment efficacy. We evaluated the accuracy of a 15-minute run-time recombinase polymerase amplification–based prototype point-of-care test (TwistDx) for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG).

Methods

Prospective, multicentre study of symptomatic and asymptomatic patients attending three English sexual health clinics. Research samples provided were additional self-collected vulvovaginal swab (SCVS) (female participants) and first-catch urine (FCU) aliquot (female and male participants). Samples were processed blind to the comparator (routine clinic CT/NG nucleic acid amplification test (NAAT)) results. Discrepancies were resolved using Cepheid CT/NG GeneXpert.

Results

Both recombinase polymerase amplification and routine clinic NAAT results were available for 392 male and 395 female participants. CT positivity was 8.9% (35/392) (male FCU), 7.3% (29/395) (female FCU) and 7.1% (28/395) (SCVS). Corresponding NG positivity was 3.1% (12/392), 0.8% (3/395) and 0.8% (3/395). Specificity and positive predictive values were 100% for all sample types and both organisms, except male CT FCU (99.7% specificity (95% confidence interval (CI) 98.4–100.0; 356/357), 97.1% positive predictive value (95% CI 84.7–99.9; 33/34)). For CT, sensitivity was ≥94.3% for FCU and SCVS. CT sensitivity for female FCU was higher (100%; 95% CI, 88.1–100; 29/29) than for SCVS (96.4%; 95% CI, 81.7–99.9; 27/28). NG sensitivity and negative predictive values were 100% in FCU (male and female).

Conclusions

This prototype test has excellent performance characteristics, comparable to currently used NAATs, and fulfils several World Health Organization ASSURED criteria. Its rapidity without loss of performance suggests that once further developed and commercialized, this test could positively affect clinical practice and public health.

Using Multiple Outcomes of Sexual Behavior to Provide Insights Into Chlamydia Transmission and the Effectiveness of Prevention Interventions in Adolescents

BACKGROUND

Mathematical models are important tools for assessing prevention and management strategies for sexually transmitted infections. These models are usually developed for a single infection and require calibration to observed epidemiological trends in the infection of interest. Incorporating other outcomes of sexual behavior into the model, such as pregnancy, may better inform the calibration process.

METHODS

We developed a mathematical model of chlamydia transmission and pregnancy in Minnesota adolescents aged 15 to 19 years. We calibrated the model to statewide rates of reported chlamydia cases alone (chlamydia calibration) and in combination with pregnancy rates (dual calibration). We evaluated the impact of calibrating to different outcomes of sexual behavior on estimated input parameter values, predicted epidemiological outcomes, and predicted impact of chlamydia prevention interventions.

RESULTS

The two calibration scenarios produced different estimates of the probability of condom use, the probability of chlamydia transmission per sex act, the proportion of asymptomatic infections, and the screening rate among men. These differences resulted in the dual calibration scenario predicting lower prevalence and incidence of chlamydia compared with calibrating to chlamydia cases alone. When evaluating the impact of a 10% increase in condom use, the dual calibration scenario predicted fewer infections averted over 5 years compared with chlamydia calibration alone [111 (6.8%) vs 158 (8.5%)].

CONCLUSIONS

While pregnancy and chlamydia in adolescents are often considered separately, both are outcomes of unprotected sexual activity. Incorporating both as calibration targets in a model of chlamydia transmission resulted in different parameter estimates, potentially impacting the intervention effectiveness predicted by the model.

Trends in Adult Chlamydia and Gonorrhea Prevalence, Incidence and Urethral Discharge Case Reporting in Morocco over 1995-2015-Estimates Using the Spectrum-Sexually Transmitted Infection Model

Trend estimations using the Spectrum-sexually transmitted infection (STI) model based on survey and surveillance data from Morocco showed declining gonorrhea and chlamydia prevalence and incidence in adults over 1995 to 2015. Supplemental digital content is available in the text.

Background

Evolving health priorities and resource constraints mean that countries require data on sexually transmitted infections (STI) trends to inform program planning and resource allocation.

Methods

The Spectrum modeling tool estimated prevalence and incidence of gonorrhea and chlamydia in Morocco's 15- to 49-year-old population, based on prevalence surveys. Incident cases, broken down between symptomatic and asymptomatic, and treated versus untreated, were compared with urethral discharge (UD) case reports, to estimate reporting completeness among treated UD cases.

Results

Gonorrhea prevalence was estimated at 0.37% (95% confidence interval [CI], 0.14–1.0%) in women and 0.32% (0.12–0.87%) in men in 2015; chlamydia prevalences were 3.8% (95% CI, 2.1–6.4%) and 3.0% (95% CI, 1.7–5.1%). Corresponding estimated numbers of new cases in women and men in 2015 were 79,598 (95% CI, 23,918–256,206) and 112,013 (95% CI, 28,700–307,433) for gonorrhea, and 291,908 (95% CI, 161,064–524,270) and 314,032 (95% CI, 186,076–559,133) for chlamydia. Gonorrhea and chlamydia prevalence had declined by an estimated 41% and 27%, respectively, over 1995 to 2015. Prevalence declines probably related to improved STI treatment coverage, and decreasing risk behaviors. Reporting completeness among treated UD cases was estimated at 46% to 77% in 2015. Reported UD cases corresponded to 13% of all estimated (symptomatic and asymptomatic) gonorrhea and chlamydia cases.

Conclusions

STI declines and improvements in treatment coverage are consistent with Morocco’s introduction of syndromic management in 2000, scale-up of prevention, and declining human immunodeficiency virus incidence. While gonorrhea is four-fold more common as cause of clinical UD cases than chlamydia, Morocco continues to suffer a large, untreated burden of chlamydia. Reliable monitoring of both STIs requires new periodic surveys and/or novel forms of affordable surveillance beyond high-risk populations.

Assessing prevalence of missed laboratory-confirmed sexually transmitted infections among women in Kingston, Jamaica: results from a secondary analysis of the Sino-Implant clinical trial

OBJECTIVES

To assess potentially missed sexually transmitted infections (STIs), we compared clinically diagnosed STIs to laboratory-confirmed diagnoses of gonorrhoea (GC), chlamydia (CT) and trichomonas (Tvag).

DESIGN

Secondary analysis of a randomised controlled trial.

SETTING

We used data and specimens previously collected for the Sino-Implant Study in Kingston, Jamaica.

PARTICIPANTS

The Sino-Implant Study randomised 414 women to receive a levonorgestrel implant at either baseline or 3 months post-enrolment to evaluate unprotected sex after implant initiation. This analysis used 254 available vaginal swab samples.

OUTCOME MEASURES

Clinically diagnosed STIs were determined from medical records by assessing clinical impressions and prescriptions. Laboratory-confirmed STIs included GC, CT and Tvag tested by Aptima Combo 2 for CT/GC and Aptima Tvag assays (Hologic, San Diego, California, USA). Log-binomial regression models fit with generalised estimating equations were used to estimate associations of clinically diagnosed STIs with laboratory-confirmed diagnoses and demographic and behavioural characteristics.

RESULTS

Overall, 195 (76.8%) women had laboratory-confirmed STI (CT, GC or Tvag) while only 65 (25.6%) women had clinically diagnosed cervicitis and/or vaginitis during the study period. Clinical diagnosis missed 79.7% of laboratory-confirmed STIs: 85% of GC (n=17/20), 78.8% of CT (n=141/179) and 80.0% of Tvag (n=180/225). Hormonal contraceptive use in the month prior to the study visit was significantly associated with clinical diagnosis at any time point (prevalence ratio (PR): 1.65, 95% CI 1.07 to 2.54). As age increased, clinically missed infections significantly decreased (PR: 0.98 per year increase, 95% CI 0.97 to 1.00).

CONCLUSIONS

The prevalence of laboratory-confirmed STIs was much higher than what was captured by clinical diagnosis. GC, CT and Tvag were not accurately detected without lab confirmation. Missed diagnoses decreased with older age. Increased laboratory capacity and refinement of the syndromic approach are needed to protect the health of sexually active Jamaican women.

TRIAL REGISTRATION NUMBER

NCT01684358.

Concordance of gonorrhoea of the rectum, pharynx and urethra in same-sex male partnerships attending a sexual health service in Melbourne, Australia

BACKGROUND

We aimed to describe anatomic site-specific concordance of gonococcal infections in partnerships of men who have sex with men (MSM).

METHODS

We conducted a cross-sectional analysis of data from MSM partnerships attending Melbourne Sexual Health Centre between March 2011 and February 2015. Logistic regression models (random effect) were used to examine the association between gonococcal infections of the urethra, rectum and pharynx. Gonococci were detected by culture at all anatomic sites.

RESULTS

The analysis included 495 partnerships. Of the men with urethral gonorrhoea, 33% (95% CI 18-52) had partners with pharyngeal gonorrhoea and 67% (95% CI 48-82) had partners with rectal gonorrhoea. The adjusted odds of having urethral gonorrhoea was 4.6 (95% CI 1.2-17.1) for a man whose partner had pharyngeal gonorrhoea, and 48.1 (95% CI 18.3-126.7) for a man whose partner had rectal gonorrhoea. Of the men with rectal gonorrhoea, 46% (95% CI 31-61) had a partner with urethral gonorrhoea and 23% (95% CI 12-37) had a partner with pharyngeal gonorrhoea. The adjusted odds of having rectal gonorrhoea was 63.9 (95% CI 24.7-165.6) for a man whose partner had urethral gonorrhoea. Of the men with pharyngeal gonorrhoea, 42% (95% CI 23-63) had a partner with rectal gonorrhoea and 23% (95% CI 9-44) had a partner with had a partner with pharyngeal gonorrhoea. The adjusted odds of having pharyngeal gonorrhoea was 8.9 (95% CI 3.2-24.6) for a man whose partner had rectal gonorrhoea. The crude odds of having pharyngeal gonorrhoea was 14.2 (95% CI 5.1-39.0) for a man whose partner had pharyngeal gonorrhoea.

CONCLUSIONS

These data provide the first estimates of concordance of anatomic site-specific gonococcal infections in MSM partnerships, and confirm that urethral gonorrhoea is contracted from both rectal and pharyngeal sites, and suggest that gonococci transmit between the rectum and pharynx. However, due to use of culture rather than NAAT, our analysis was not adequately powered to assess pharynx-to-pharynx transmission of gonococci.