Pharmacodynamic evaluation of ceftriaxone single-dose therapy (0.125-1 g) to eradicate ceftriaxone-susceptible and ceftriaxone-resistant Neisseria gonorrhoeae strains in a hollow fibre infection model for gonorrhoea

BACKGROUND

Antimicrobial resistance in Neisseria gonorrhoeae is threatening the gonorrhoea treatment, and optimizations of the current ceftriaxone-treatment regimens are crucial. We evaluated the pharmacodynamics of ceftriaxone single-dose therapy (0.125-1 g) against ceftriaxone-susceptible and ceftriaxone-resistant gonococcal strains, based on EUCAST ceftriaxone-resistance breakpoint (MIC > 0.125 mg/L), in our hollow fibre infection model (HFIM) for gonorrhoea.

METHODS

Gonococcal strains examined were WHO F (ceftriaxone-susceptible, MIC < 0.002 mg/L), R (ceftriaxone-resistant, MIC = 0.5 mg/L), Z (ceftriaxone-resistant, MIC = 0.5 mg/L) and X (ceftriaxone-resistant, MIC = 2 mg/L). Dose-range HFIM 7 day experiments simulating ceftriaxone 0.125-1 g single-dose intramuscular regimens were conducted.

RESULTS

Ceftriaxone 0.125-1 g single-dose treatments rapidly eradicated WHO F (wild-type ceftriaxone MIC). Ceftriaxone 0.5 and 1 g treatments, based on ceftriaxone human plasma pharmacokinetic parameters, eradicated most ceftriaxone-resistant gonococcal strains (WHO R and Z), but ceftriaxone 0.5 g failed to eradicate WHO X (high-level ceftriaxone resistance). When simulating oropharyngeal gonorrhoea, ceftriaxone 0.5 g failed to eradicate all the ceftriaxone-resistant strains, while ceftriaxone 1 g eradicated WHO R and Z (low-level ceftriaxone resistance) but failed to eradicate WHO X (high-level ceftriaxone resistance). No ceftriaxone-resistant mutants were selected using any ceftriaxone treatments.

CONCLUSIONS

Ceftriaxone 1 g single-dose intramuscularly cure most of the anogenital and oropharyngeal gonorrhoea cases caused by the currently internationally spreading ceftriaxone-resistant gonococcal strains, which should be further confirmed clinically. A ceftriaxone 1 g dose (±azithromycin 2 g) should be recommended for first-line empiric gonorrhoea treatment. This will buy countries some time until novel antimicrobials are licensed. Using ceftriaxone 1 g gonorrhoea treatment, the EUCAST ceftriaxone-resistance breakpoint is too low.

Moving Toward Online-Based Sexually Transmitted Infection Testing and Treatment Services for Young People: Who Will Use It and What Do They Want?

BACKGROUND

The market for online sexually transmitted infection (STI) services is rapidly expanding. Online health services often have unequal uptake among different demographics of the population. There is a need to understand how different online delivery options for STI testing may appeal to different groups of young people, particularly young people who have higher rates of STI diagnoses.

METHODS

An online survey of young Australians aged 16 to 29 years was conducted to understand service preferences regarding consultation (telehealth, fully automated questionnaire), testing (electronic pathology form, at-home self-sampling), and treatment (e-prescriptions, mailed oral tablets). Multivariable multinomial logistic regression examined associations between user characteristics and service preferences, and adjusted relative risk ratios (aRRRs) and 95% confidence intervals (CIs) are presented.

RESULTS

Among 905 respondents, rural youth were more likely to prefer fully automated questionnaires (aRRR, 1.9; 95% CI, 1.0-3.5) over telehealth consultations, whereas culturally and linguistically diverse (CALD) youth were less likely (aRRR, 0.4; 95% CI, 0.2-0.7). Rural youth preferred at-home self-sampling kits (aRRR, 1.9; 95% CI, 1.3-2.7) over electronic forms for on-site collection at pathology centers, with the opposite for CALD youth (aRRR, 0.7; 95% CI, 0.5-1.0). Receiving oral antibiotics by mail was preferred by rural youth (aRRR, 2.3; 95% CI, 1.1-4.6) over for in-clinic treatment, but not for CALD youth (aRRR, 0.5; 95% CI, 0.4-0.8).

CONCLUSIONS

Our findings suggest that rural youth tend to prefer self-navigated and automated options, whereas CALD prefer options with greater provider engagement. Online STI service providers should consider how different service options may affect equitable uptake across the population and implications for addressing disparities in testing and treatment.

STI pathogens in the oropharynx: update on screening and treatment

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Can a cup a day keep cancer away? A systematic review exploring the potential of coffee constituents in preventing oral squamous cell carcinoma

BACKGROUND

Coffee is one of the most consumed beverages in the world. Containing an abundance of bioactive molecules including polyphenols and flavonoids, the constituents of this beverage may exert antiproliferative, antioxidant and anti-inflammatory effects.

METHODS

We conducted a systematic review to summarise the available evidence on the anticancer effects of coffee constituents and their potential therapeutic use for oral squamous cell carcinoma (OSCC). Studies were identified through a comprehensive search of OVID MEDLINE, OVID EMBASE and Web of Science, including articles from any year up to 15 May 2023.

RESULTS

Of the 60 reviewed papers, 45 were in vitro, 1 was in silico and 8 were in vivo exclusively. The remaining studies combined elements of more than one study type. A total of 55 studies demonstrated anti-proliferative effects, whilst 12 studies also investigated migration and invasion of neoplastic cells. The constituents studied most frequently were quercetin and epigallocatechin gallate (EGCG), demonstrating various cytotoxic effects whilst also influencing apoptotic mechanisms in cancer cell lines. Dose-dependent responses were consistently found amongst the studied constituents.

CONCLUSION

Whilst there was heterogeneity of study models and methods, consistent use of specific models such as SCC25 for in vitro studies and golden hamsters for in vivo studies enabled relative comparability. The constituents of coffee have gained significant interest over the last 30 years, particularly in the last decade, and present an area of interest with significant public health implications. Currently, there is a paucity of literature on utilization of active coffee constituents for the therapeutic treatment of oral cancers.

Pharmacodynamics of zoliflodacin plus doxycycline combination therapy against Neisseria gonorrhoeae in a gonococcal hollow-fiber infection model

Antimicrobial resistance in the sexually transmitted bacterium Neisseria gonorrhoeae is compromising the management and control of gonorrhea globally. Optimized use and enhanced stewardship of current antimicrobials and development of novel antimicrobials are imperative. The first in class zoliflodacin (spiropyrimidinetrione, DNA Gyrase B inhibitor) is a promising novel antimicrobial in late-stage clinical development for gonorrhea treatment, i.e., the phase III randomized controlled clinical trial (ClinicalTrials.gov Identifier: NCT03959527) was recently finalized, and zoliflodacin showed non-inferiority compared to the recommended ceftriaxone plus azithromycin dual therapy. Doxycycline, the first-line treatment for chlamydia and empiric treatment for non-gonococcal urethritis, will be frequently given together with zoliflodacin because gonorrhea and chlamydia coinfections are common. In a previous static in vitro study, it was indicated that doxycycline/tetracycline inhibited the gonococcal killing of zoliflodacin in 6-h time-kill curve analysis. In this study, our dynamic in vitro hollow-fiber infection model (HFIM) was used to investigate combination therapies with zoliflodacin and doxycycline. Dose-range experiments using the three gonococcal strains WHO F (susceptible to relevant therapeutic antimicrobials), WHO X (extensively drug-resistant, including ceftriaxone-resistant; zoliflodacin-susceptible), and SE600/18 (zoliflodacin-susceptible strain with GyrB S467N substitution) were conducted simulating combination therapy with a single oral dose of zoliflodacin 0.5-4 g combined with a doxycycline daily oral dose of 200 mg administered as 100 mg twice a day, for 7 days (standard dose for chlamydia treatment). Comparing combination therapy of zoliflodacin (0.5-4 g single dose) plus doxycycline (200 mg divided into 100 mg twice a day orally, for 7 days) to zoliflodacin monotherapy (0.5-4 g single dose) showed that combination therapy was slightly more effective than monotherapy in the killing of N. gonorrhoeae and suppressing emergence of zoliflodacin resistance. Accordingly, WHO F was eradicated by only 0.5 g single dose of zoliflodacin in combination with doxycycline, and WHO X and SE600/18 were both eradicated by a 2 g single dose of zoliflodacin in combination with doxycycline; no zoliflodacin-resistant populations occurred during the 7-day experiment when using this zoliflodacin dose. When using suboptimal (0.5-1 g) zoliflodacin doses together with doxycycline, gonococcal mutants with increased zoliflodacin MICs, due to GyrB D429N and the novel GyrB T472P, emerged, but both the mutants had an impaired biofitness. The present study shows the high efficacy of zoliflodacin plus doxycycline combination therapy using a dynamic HFIM that more accurately and comprehensively simulate gonococcal infection and their treatment, i.e., compared to static in vitro models, such as short-time checkerboard experiments or time-kill curve analysis. Based on our dynamic in vitro HFIM work, zoliflodacin plus doxycycline for the treatment of both gonorrhea and chlamydia can be an effective combination.

Web-Based STI/HIV Testing Services Available for Access in Australia: Systematic Search and Analysis

BACKGROUND

Sexually transmitted infection (STI) rates continue to rise in Australia, and timely access to testing and treatment is crucial to reduce transmission. Web-based services have been viewed as a way to improve timely access to STI/HIV testing and have proliferated in recent years. However, the regulation of these services in Australia is minimal, leading to concerns about their quality. The purpose of this review was to systematically identify web-based STI/HIV testing services available in Australia and assess them on aspects of quality, reliability, and accessibility.

OBJECTIVE

We aim to systematically identify and assess web-based STI/HIV testing services available in Australia.

METHODS

A Google search of Australian web-based services was conducted in March 2022 and repeated in September 2022 using Boolean operators and search terms related to test services (eg, on the internet or home), STIs (eg, chlamydia or gonorrhea), and test type (eg, self-test). The first 10 pages were assessed, and services were categorized as self-testing (ST; test at home), self-sampling (SS; sample at home and return to laboratory), or self-navigated pathology (SNP; specimens collected at pathology center). Website reliability was assessed against the Health on the Net Foundation code of conduct, and service quality was assessed using a scorecard that was developed based on similar reviews, Australian guidelines for in-person services, and UK standards. Additionally, we looked at measures of accessibility including cost, rural access, and time to test results.

RESULTS

Seventeen services were identified (8 ST, 2 SS, and 7 SNP). Only 4 services offered recommended testing for all 4 infections (chlamydia, gonorrhea, syphilis, and HIV) including genital, anorectal, and oropharyngeal sites, and 5 offered tests other than those recommended by Australian testing guidelines (eg, Ureaplasma). Nine services (1 SNP, 8 self-test) had no minimum age requirements for access. Reliability scores (scale 0-8) were similar between all services (range 4.75-8.0). Quality weighted scores (scale 0-58) were similar between SNP and SS services (average 44.89, SD 5.56 and 44.75, SD 1.77, respectively) but lower for ST services (22.66, SD 8.93; P=.002). Government-funded services were of higher quality than private services (43.54, SD 6.71 vs 29.43, SD 13.55; P=.03). The cost for services varied between SNP (Aus $0-$595; ie, US $0-$381.96), self-sample (Aus $0; ie, US $0), and ST (Aus $0-$135; ie, US $0-$86.66). The time to test results was much shorter for SNP services (~4 days) than for SS (~12 days) and ST (~14 days).

CONCLUSIONS

This review identified considerable variability in the quality and reliability of the web-based STI/HIV testing services in Australia. Given the proliferation and use of these services will likely increase, it is imperative that Australia develops national standards to ensure the standard-of-care offered by web-based STI/HIV testing services is appropriate to protect Australian users from the impact of poorly performing and inappropriate tests.

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

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

eSexualHealth: Preferences to use technology to promote sexual health among men who have sex with men and trans and gender diverse people

Objectives

Gay, bisexual and other men who have sex with men (GBMSM) and trans and gender diverse (TGD) people are disproportionately affected by poorer sexual health outcomes compared to heterosexual populations. We aimed to explore the preferences of GBMSM and TGD for using eHealth for sexual health (eSexualHealth).

Methods

We distributed an anonymous online survey from April to August 2021among the lesbian, gay, bisexual, transgender, intersex, queer and other people of diverse sexuality or gender (LGBTIQA+) community in Australia. The survey collected data on sociodemographic characteristics and sexual behaviors, their preferences for app/website functions and preferred HIV and sexually transmitted infection (STI) testing reminders. We used descriptive statistics to summarize the characteristics of the study population. Free-text responses were thematically analyzed.

Results

Of 466 participants included, most identified as cisgender males (92.7%). The median age was 48 [interquartile range (IQR): 37-56]. For accessing sexual health-related information, 160 (34.6%) would use either a website or an app, 165 (32.7%) would prefer a website, 119 (25.8%) would prefer an app, and 33 (7.1%) would not use either platform. There was no significant difference between GBMSM and TGD people. Participants were most interested in information about STI clinics, HIV/STI hotspots, and sexual health education. Participants stressed the need for privacy and anonymity when using eHealth. Regarding reminders to test for HIV/STIs, receiving regular SMS was most popular (112/293, 38.2%), followed by regular emails (55/293 18.8%) and a reminder function on their phone (48/293, 16.4%).

Conclusion

Our study suggests a promising future for eHealth among GBMSM and TGD people. Sexual health is still a stigmatized area, and eHealth may circumvent barriers this population faces.

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

INTRODUCTION

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

METHODS AND ANALYSIS

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

ETHICS AND DISSEMINATION

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

TRIAL REGISTRATION NUMBER

ACTRN12621000339853.

Comparison of gastrointestinal side effects from different doses of azithromycin for the treatment of gonorrhoea

OBJECTIVES

Azithromycin is commonly used to treat Neisseria gonorrhoeae. We compared its gastrointestinal side effects using 1 g single, 2 g single or 2 g split (i.e. 1 g plus 1 g 6-12 h later) dosing, representing our clinic's changing guidelines over the study period.

METHODS

We recruited consecutive sexual health clinic patients who received azithromycin (and 500 mg ceftriaxone) for uncomplicated gonorrhoea. Each patient received a text message 48 h after their attendance to complete a questionnaire.

RESULTS

Patients received 1 g single (n = 271), 2 g single (218) or 2 g split (105) doses. Vomiting was less common for 1 g versus 2 g single dose [1.1% versus 3.7%; risk difference (RD): -2.6%; 95% CI: -0.2 to -5.4] and 2 g split versus 2 g single dose (0.9% versus 3.7%; RD: -2.8%; 95% CI: -0.3 to -5.8). Nausea was less common for 1 g versus 2 g single dose (13.7% versus 43.1%; RD: -29.5%; 95% CI: -21.7 to -37.2) and 2 g split versus 2 g single dose (16.4% versus 43.1%; RD: -26.8; 95% CI: -17.2 to -36.3). Diarrhoea was less common for 1 g versus 2 g single dose (25.5% versus 50.9%; RD: -25.5%; 95% CI: -17.0 to -33.9) and 2 g split versus 2 g single dose (30.9% versus 50.9%; RD: -20.0; 95% CI: -9.1 to -30.9). Almost all were willing to retake the same dosing for gonorrhoea in the future: 97% for 1 g single; 94% for 2 g single; and 97% for 2 g split dose.

CONCLUSIONS

Azithromycin 2 g split dose for gonorrhoea resulted in significantly less vomiting, nausea and diarrhoea than a 2 g single dose.

Rectal chlamydia infections: implications for reinfection risk, screening, and treatment guidelines

PURPOSE OF REVIEW

Rectal chlamydia is a prevalent sexually transmissible infection in both men who have sex with men (MSM) and in women. Screening is recommended for MSM but remains controversial for women. The optimal treatment for rectal chlamydia is now conclusive but interpreting and managing positive results remains challenging. Infections among MSM are increasing and strategies are needed to reduce incident infections. This review summarizes recent developments for the screening and management of rectal chlamydia and its implications on reinfection.

RECENT FINDINGS

Reinfections in MSM may be occurring due to resumption of sex soon after treatment whereas repeat infections in women may occur due to autoinoculation in the absence of sex. Doxycycline is now first-line treatment but its role in chemoprophylaxis remains unclear. False positive results remain an issue, but the development of viability assays may prove useful in future to determine true infections.

SUMMARY

Doxycycline is the first-line treatment for rectal chlamydia and in women may prevent infections at the urogenital site. Viability assays can help to reduce antibiotic use once developed. The role of routine screening of rectal chlamydia in women remains unclear and this debate may soon include asymptomatic infections in MSM.

What do young people in high-income countries want from STI testing services? A systematic review

BACKGROUND

There are upward trends of STI rates among young people in most high-income countries. We reviewed the literature to provide a summary of information to support health services with the aim of increasing testing of STIs among young people living in high-income countries.

METHODS

We conducted a systematic review (Prospero: CRD42020179720) using PubMed, Embase, PsychINFO and CINAHL. The search was performed on 10 January 2020 for studies between January 2000 and 10 January 2020. Two reviewers independently screened articles, and any discrepancies were resolved by a third reviewer. Studies were included if they were performed in high-income countries and contained data on both young people (<26 years) and STI testing preferences. Data regarding the characteristics of STI testing services that young people preferred was extracted. We categorised these characteristics using the framework of a social-ecological model.

RESULTS

We identified 1440 studies, and 63 studies were included in the final review. We found 32 studies that addressed individual factors, 62 studies that addressed service factors and 17 studies that addressed societal factors. At an individual level, we identified eight attributes including the need for improved sexual health education. At a service level, 14 attributes were identified including preferences from different subgroups of young people (such as sexual and ethnic minorities) for the types of services. At a societal level, we identified two attributes including the need to address stigma associated with STIs.

CONCLUSION

We provide an overview of the growing body of literature capturing the preferences of young people for STI testing services. To optimise the uptake of STI testing among young people, factors from all socioecological levels should be considered. In addition, understanding and accounting for distinct preferences from subgroups of young people could increase demand for STI testing services for those at greatest need.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Azithromycin or Doxycycline for Asymptomatic Rectal Chlamydia trachomatis

BACKGROUND

Rectal chlamydia is a common bacterial sexually transmissible infection among men who have sex with men. Data from randomized, controlled trials are needed to guide treatment.

METHODS

In this double-blind trial conducted at five sexual health clinics in Australia, we randomly assigned men who have sex with men and who had asymptomatic rectal chlamydia to receive doxycycline (100 mg twice daily for 7 days) or azithromycin (1-g single dose). Asymptomatic chlamydia was selected as the trial focus because more than 85% of men with rectal chlamydia infection are asymptomatic, and clinical guidelines recommend a longer treatment course for symptomatic infection. The primary outcome was a negative nucleic acid amplification test for rectal chlamydia (microbiologic cure) at 4 weeks.

RESULTS

From August 2016 through August 2019, we enrolled 625 men (314 in the doxycycline group and 311 in the azithromycin group). Primary outcome data were available for 290 men (92.4%) in the doxycycline group and 297 (95.5%) in the azithromycin group. In the modified intention-to-treat population, a microbiologic cure occurred in 281 of 290 men (96.9%; 95% confidence interval [CI], 94.9 to 98.9) in the doxycycline group and in 227 of 297 (76.4%; 95% CI, 73.8 to 79.1) in the azithromycin group, for an adjusted risk difference of 19.9 percentage points (95% CI, 14.6 to 25.3; P<0.001). Adverse events that included nausea, diarrhea, and vomiting were reported in 98 men (33.8%) in the doxycycline group and in 134 (45.1%) in the azithromycin group (risk difference, -11.3 percentage points; 95% CI, -19.5 to -3.2).

CONCLUSIONS

A 7-day course of doxycycline was superior to single-dose azithromycin in the treatment of rectal chlamydia infection among men who have sex with men. (Funded by the National Health and Medical Research Council; RTS Australian New Zealand Clinical Trials Registry number, ACTRN12614001125617.).

Development of New Antimicrobials for Urogenital Gonorrhea Therapy: Clinical Trial Design Considerations

Gonorrhea remains a major public health challenge, and current recommendations for gonorrhea treatment are threatened by evolving antimicrobial resistance and a diminished pipeline for new antibiotics. Evaluations of potential new treatments for gonorrhea currently make limited use of new understanding of the pharmacokinetic and pharmacodynamic contributors to effective therapy, the prevention of antimicrobial resistance, and newer designs for clinical trials. They are hampered by the requirement to utilize combination ceftriaxone/azithromycin therapy as the comparator regimen in noninferiority trials designed to seek an indication for gonorrhea therapy. Evolving gonococcal epidemiology and clinical trial design constraints hinder the enrollment of those populations at the greatest risk for gonorrhea (adolescents, women, and persons infected with antibiotic-resistant Neisseria gonorrhoeae). This article summarizes a recent meeting on the evaluation process for antimicrobials for urogenital gonorrhea treatment and encourages the consideration of new designs for the evaluation of gonorrhea therapy.

Factors associated with rectal pH among men who have sex with men

Background Rectal chlamydia treatment failures up to 22% with azithromycin 1 g have been reported, but low tissue concentrations are unlikely to be the cause. Anecdotally, low rectal pH could reduce rectal azithromycin concentrations, with in vitro studies reporting higher minimum inhibitory concentrations (MICs) with lower pHs for antibiotics used to treat sexually transmissible infections (STIs). Leucocytes arising from an inflammatory immune response could also lower pH and efficacy. We examined factors that may alter rectal pH and potentially influence treatment outcomes.

METHODS

We recruited consecutive men who have sex with men (MSM) from a Dutch STI clinic between October 2016 and July 2018 who had not used antibiotics in the past fortnight. Rectal mucus collected under anoscopy using a cotton swab was used to wet a pH indicator strip. Logistic regression was used to examine the association of pH <8.0 to demographic, dietary, sexual health and behaviour data, recent medication use and STI diagnosis.

RESULTS

In total, 112 MSM were recruited (median age 37 years). It was found that 45% and 39% of men were HIV positive or had a rectal infection, respectively. And 50% had a rectal pH <8.0, with 27% reporting a pH between 6.0 and 6.5 where treatment failure is thought to occur for azithromycin. The adjusted odds ratio (OR) of a pH <8.0 showed that being aged 36-45 years (OR 6.7; 95%CI: 1.9-23.4) or having high rectal leucocytes in a Gram smear (OR 0.3; 95%CI: 0.1-0.7) were significantly associated with a low and high rectal pH, respectively.

CONCLUSIONS

Lower rectal pH among MSM is associated with older age and could influence the rectal pharmacokinetics of azithromycin and other drugs influenced by pH and may therefore affect treatment outcomes.

Prevalence of sexually transmissible infections and HIV in men attending sex-on-premises venues in Australia: a systematic review and meta-analysis of observational studies

Background In Australia, men who have sex with men (MSM) have high rates sexually transmissible infections (STIs) and sex-on-premises venue (SOPV) patrons are at risk. This paper assesses Neisseria gonorrhoeae (NG), Chlamydia trachomatis (CT), syphilis and HIV prevalence in men tested at Australian SOPVs and describes testing services.

METHODS

EMBASE, Medline, PubMed and international conference proceedings were searched for articles reporting on-site SOPV testing between 1 January 2000 and 31 January 2017. Meta-analysis calculated pooled prevalence estimates of STIs by anatomical site.

RESULTS

Twelve cross-sectional studies were identified. Most (8/12) were local sexual health clinics (SHC) outreach services. Participants' mean age was 41.1 years (95% confidence interval (CI) 37.0-43.3; range 17 to 84 years). Testing included CT and NG (9/12), HIV (8/12) and syphilis (5/12). CT and NG prevalence overall summary estimates were 3.4% (95% CI 1.9-5.2%, I2 = 88.7%, P < 0.01) and 1.3% (95% CI 0.7-2.2%, I2 = 75.5%, P < 0.01) respectively. CT and NG prevalence was highest in the ano-rectum and oro-pharynx respectively. The HIV and syphilis pooled estimates were 2.3% (95% CI 1.6-2.9%, I2 = 93.1%, P < 0.01) and 3.2% (95% CI 1.8-4.6%, I2 = 72.8%, P < 0.01) respectively. Participation rate varied.

CONCLUSION

This review examines HIV and STI testing in Australian SOPVs before HIV pre-exposure prophylaxis (PrEP). Findings indicate a high prevalence of STIs. PrEP use and resultant condomless sex may influence STI prevalence. Further research is required to determine the effect of PrEP on the STI prevalence among SOPV patrons.

Treatment Outcomes for Rectal Lymphogranuloma Venereum in Men Who Have Sex with Men Using Doxycycline, Azithromycin, or Both: A Review of Clinical Cases

BACKGROUND

Treatment for rectal lymphogranuloma venereum where doxycycline 100 mg twice daily for 21 days was used-either alone or together with azithromycin 1 g single dose-resulted in microbiological cure of 97%. These data support doxycycline 100 mg twice daily for 21 days as the preferred treatment for rectal lymphogranuloma venereum.

Pharmacokinetics of a single 1g dose of azithromycin in rectal tissue in men

Chlamydia is the most common bacterial sexually transmitted infection among men who have sex with men. Repeat infection following treatment with 1g azithromycin is common and treatment failure of up to 22% has been reported. This study measured the pharmacokinetics of azithromycin in rectal tissue in men following a single 1g dose to assess whether azithromycin reaches the rectal site in adequate concentrations to kill chlamydia. Ten healthy men took a single oral dose of 1g azithromycin and provided nine self-collected swabs and one blood sample over 14 days. Participant demographics, medications, sexual behaviour, treatment side effects, lubricant use and douching practices were recorded with each swab. Drug concentration over time was determined using liquid chromatography-mass spectrometry and total exposure (AUC0-∞) was estimated from the concentration-time profiles. Following 1g of azithromycin, rectal concentrations peaked after a median of 24 hours (median 133mcg/g) and remained above the minimum inhibitory concentration for chlamydia (0.125mcg/mL) for at least 14 days in all men. AUC0-∞ was the highest ever reported in human tissue (13103((mcg/g).hr)). Tissue concentrations were not associated with weight (mg/kg), but data suggest that increased gastric pH could increase azithromycin levels and diarrhoea or use of water-based lubricants could decrease concentrations. High and sustained concentrations of azithromycin were found in rectal tissue following a single 1g dose suggesting that inadequate concentrations are unlikely to cause treatment failure. Factors effecting absorption (pH and diarrhoea) or drug depletion (douching and water-based lubricants) may be more important determinants of concentrations in situ.

A snapshot of Chlamydia trachomatis genetic diversity using multilocus sequence type analysis in an Australian metropolitan setting

High-resolution screening methodologies which enable the differentiation of Chlamydia trachomatis at the strain level, directly from clinical samples, can provide the detailed information required for epidemiological questions such as the dynamics of treatment failure. In addition, they give a detailed snapshot of circulating C. trachomatis genetic variation, data which are currently lacking for the Australian population. In the context of two Australian clinical trials, we assessed the genetic diversity of C. trachomatis and compared these to strains circulating globally. We used high-resolution multilocus sequence typing (MLST) of five highly variable genetic regions of C. trachomatis to examine variation in Australia. Samples with established genovars were drawn from a pool of 880 C. trachomatis-positive samples from two clinical studies, whereby 76 sample pairs which remained C. trachomatis-positive for the same genovar after treatment underwent MLST analysis to distinguish between treatment failure and reinfection. MLST analysis revealed a total of 25 sequence types (STs), six new allele variants and seven new STs not described anywhere else in the world, when compared to those in the international C. trachomatis MLST database. Of the eight most common global STs, seven were found in Australia (four derived from men who have sex with men (MSM) and three from heterosexuals). Newly identified STs were predominantly found in samples from the MSM population. In conclusion, MLST provided a diverse C. trachomatis strain profile, with novel circulating STs, and could be used to identify local sexual networks to focus on interventions such as testing and partner notification to prevent reinfection.

Systematic Review and Meta-Analysis of Doxycycline Efficacy for Rectal Lymphogranuloma Venereum in Men Who Have Sex with Men

A high microbial cure rate was shown with 100 mg doxycycline twice daily for 21 days.

Rectal lymphogranuloma venereum (LGV) has reemerged as a sexually transmitted infection among men who have sex with men (MSM), particularly those who are HIV-positive. We undertook a systematic review and meta-analysis to determine the efficacy of doxycycline (100 mg 2×/d for 21 days) for rectal LGV in MSM. Nine studies were included: 4 prospective, 4 retrospective, and 1 combined retrospective and prospective. In total, 282 MSM with rectal LGV were included in the studies. All studies reported using nucleic acid amplification tests to assess microbial cure. Most patients (>80%) had symptomatic rectal infection. The fixed-effects pooled efficacy for doxycycline was 98.5% (95% CI 96.3%–100%, I² = 0%; p = 0.993). Doxycycline at 100 mg twice daily for 21 days demonstrated a high microbial cure rate. These data support doxycycline at this dosage and duration as first-line therapy for rectal LGV in MSM.

Is it time to switch to doxycycline from azithromycin for treating genital chlamydial infections in women? Modelling the impact of autoinoculation from the gastrointestinal tract to the genital tract

Background

Single-dose azithromycin is recommended over multi-dose doxycycline as treatment for chlamydial infection. However, even with imperfect adherence, doxycycline is more effective in treating genital and rectal infection. Recently, it has been suggested that autoinoculation from the rectum to the genitals may be a source of persistent chlamydial infection in women. We estimated the impact autoinoculation may have on azithromycin and doxycycline effectiveness.

Methods

We estimate treatment effectiveness using a simple mathematical model, incorporating data on azithromycin and doxycycline efficacy from recent meta-analyses, and data on prevalence of rectal infection in women with genital chlamydial infection.

Results

When the possibility of autoinoculation is taken into account, we calculate that doxycycline effectiveness may be 97% compared to just 82% for azithromycin.

Conclusions

Consideration should be given to re-evaluating azithromycin as the standard treatment for genital chlamydia in women.

Treatment of rectal chlamydia infection may be more complicated than we originally thought

Rectal chlamydia diagnoses have been increasing among MSM and may also rise among women as anal sex rates increase among heterosexuals. However, there is growing concern about treatment for rectal chlamydia with treatment failures of up to 22% being reported. This article addresses factors that may be contributing to treatment failure for rectal chlamydia, including the pharmacokinetic properties of azithromycin and doxycycline in rectal tissue, the ability of chlamydia to transform into a persistent state that is less responsive to antimicrobial therapy, the impact of the rectal microbiome on chlamydia, heterotypic resistance, failure to detect cases of lymphogranuloma venereum and the performance of screening tests. If we are to reduce the burden of genital chlamydia, treatment for rectal chlamydia must be efficacious. This highlights the need for randomized controlled trial evidence comparing azithromycin with doxycycline for the treatment of rectal chlamydia.

Sex and sport: sexual risk behaviour in young people in rural and regional Victoria

BACKGROUND

To determine the prevalence of chlamydia and understand sexual risk behaviour in 16-29 year olds in rural Victoria through a chlamydia testing program undertaken at local sporting clubs.

METHODS

Young people were recruited from the Loddon Mallee region of Victoria, Australia between May and September 2007. After a night of sporting practice, participants provided a first pass urine sample and completed a brief questionnaire about sexual risk behaviour. Those positive for chlamydia were managed by telephone consultation with a practitioner from Melbourne Sexual Health Centre.

RESULTS

A total of 709 young people participated (77% male, 23% female) in the study; 77% were sexually active. Overall chlamydia prevalence in sexually active participants was 5.1% (95% confidence interval [CI]: 3.4-7.3); 7.4% in females (95% CI: 3.5-13.6) and 4.5% in males (95% CI: 2.7-6.9). Approximately 60% of males and 20% of females consumed alcohol at high 'Risky Single Occasion Drinking' levels at least weekly and 60% had used an illicit drug in their lifetime. Nearly 45% reported having sex in the past year when they usually would not have because they were too drunk or high. Sexually transmissible infection (STI) knowledge was generally poor and only 25% used a condom the last time they had sex.

CONCLUSION

Chlamydia prevalence was high in our study population. Many participants had poor knowledge about STIs and low condom use. These findings combined with high levels of risky alcohol use and having sex while intoxicated highlights the need for programs in rural and regional Victoria that combine both STI testing and prevention and education programs.