Postexposure Doxycycline to Prevent Bacterial Sexually Transmitted Infections

Doxycycline Postexposure Prophylaxis to Prevent Bacterial Sexually Transmitted Infection

This JAMA Guidelines Synopsis summarizes the 2024 Centers for Disease Control and Prevention guidelines on use of doxycycline postexposure prophylaxis (doxyPEP) for bacterial sexually transmitted infection prevention.

Chlamydial Proctitis Mimicking Inflammatory Bowel Disease in a Young Active Duty Sailor With Undiagnosed Human Immunodeficiency Virus Infection: A Case Report

Proctitis is an inflammation of the lining of the rectum that can be either acute or chronic in presentation. Symptoms include rectal bleeding, constipation, rectal discharge, rectal pain, and tenesmus. It is commonly associated with inflammatory bowel diseases (IBDs) such as ulcerative colitis and Crohn's disease. However, it is important to consider the infectious causes of proctitis such as the sexually transmitted infections (STIs), especially Chlamydia trachomatis and Neisseria gonorrhoeae, as these can mimic the symptoms and pathology of IBD. We present the case of a young male sailor with subacute rectal bleeding who was hospitalized with initial concern for an index presentation of IBD. Endoscopic evaluation revealed proctitis although findings were atypical for inflammation related to IBD. Acquisition of additional history revealed that he had both receptive and insertive anal intercourse with both male and female partners. A full STI screening, including HIV was performed. Results were positive for both rectal C. trachomatis and HIV antigen and antibody serology, which were confirmed as HIV-1 on confirmatory testing. He was treated with doxycycline for his chlamydial proctitis with symptom resolution and was also initiated on antiretroviral therapy for his HIV infection. This case highlights the importance of obtaining a sexual history and considering STIs as a cause of proctitis, as this will ensure proper screenings and prompt subsequent treatment and potentially avoid unnecessary endoscopic and medical evaluation, which could potentially worsen the underlying process.

Terminal complement complexes with or without C9 potentiate antimicrobial activity against Neisseria gonorrhoeae

The complement cascade is a front-line defense against pathogens. Complement activation generates the membrane attack complex (MAC), a 10-11 nm diameter pore formed by complement proteins C5b through C8 and polymerized C9. The MAC embeds within the outer membrane of Gram-negative bacteria and displays bactericidal activity. In the absence of C9, C5b-C8 complexes can form 2-4 nm pores on membranes, but their relevance to microbial control is poorly understood. Deficiencies in terminal complement components uniquely predispose individuals to infections by pathogenic Neisseria, including N. gonorrhoeae (Gc). Increasing antibiotic resistance in Gc makes new therapeutic strategies a priority. Here, we demonstrate that MAC formed by complement activity in human serum disrupts the Gc outer and inner membranes, potentiating the activity of antimicrobials against Gc and re-sensitizing multidrug resistant Gc to antibiotics. C9-depleted serum also disrupts Gc membranes and exerts antigonococcal activity, effects that are not reported in other Gram-negative bacteria. C5b-C8 complex formation potentiates Gc sensitivity to azithromycin but not lysozyme. These findings expand our mechanistic understanding of complement lytic activity, suggest a size limitation for terminal complement-mediated enhancement of antimicrobials against Gc, and suggest complement manipulation can be used to combat drug-resistant gonorrhea.

Importance

The complement cascade is a front-line arm of the innate immune system against pathogens. Complement activation results in membrane attack complex (MAC) pores forming on the outer membrane of Gram-negative bacteria, resulting in bacterial death. Individuals who cannot generate MAC are specifically susceptible to infection by pathogenic Neisseria species including N. gonorrhoeae (Gc). High rates of gonorrhea and its complications like infertility, and high-frequency resistance to multiple antibiotics, make it important to identify new approaches to combat Gc. Beyond direct anti-Gc activity, we found the MAC increases the ability of antibiotics and antimicrobial proteins to kill Gc and re-sensitizes multidrug-resistant bacteria to antibiotics. The most terminal component, C9, is needed to potentiate the anti-Gc activity of lysozyme, but azithromycin activity is potentiated regardless of C9. These findings highlight the unique effects of MAC on Gc and suggest novel translational avenues to combat drug-resistant gonorrhea.

Re-visiting the potential impact of doxycycline post-exposure prophylaxis (doxy-PEP) on the selection of doxycycline resistance in Neisseria commensals

Doxycycline post-exposure prophylaxis (doxy-PEP) is a preventative strategy demonstrated to reduce bacterial sexually transmitted infections in high-risk populations. However, the impact of doxy-PEP on antibiotic resistance acquisition in key members of our microbiomes, is as of yet unclear. For example, commensal Neisseria are known reservoirs of resistance for gonococci through horizontal gene transfer (HGT), and are more likely to experience bystander selection due to doxy-PEP as they are universally carried. Thus, the consequences of doxycycline selection on commensal Neisseria will be critical to investigate to understand possible resistance mechanisms that may be transferred to an important human pathogen. Here, we use in vitro antibiotic gradients to evolve four Neisseria commensals (N. cinerea, N. canis, N. elongata, and N. subflava, n=4 per species) across a 20-day time course; and use whole genome sequencing to nominate derived mutations. After selection, 12 of 16 replicates evolved doxycycline resistance (> 1 μg/mL). Across resistant lineages: An A46T substitution in the repressor of the Mtr efflux pump (MtrR) and a V57M substitution in the 30 ribosomal protein S10 were clearly associated with elevated MICs. Additional mutations in ribosomal components also emerged in strains with high MICs (i.e., 16S rRNA G1057C, RplX A14T). We find the MtrR 46T, RpsJ 57M, and RplX 14T circulating in natural commensal populations. Furthermore, in vitro co-evolution of N. gonorrhoeae with Neisseria commensals demonstrated rapid transfer of the pConj plasmid to N. subflava and N. cinerea, and pbla to N. cinerea. Finally, collection of novel commensals from human hosts reveals 46% of isolates carrying doxycycline resistance; and doxycycline resistance was significantly greater in participants self-reporting doxycycline use in the past 6 months. High-level doxycycline resistance (> 8 μg/mL) was always associated with carriage of the ribosomal protection protein (tetM) and pConj. Ultimately, characterizing the contemporary prevalence of doxycycline resistance, and underlying resistance mechanisms, in commensal communities may help us to predict the long-term impact of doxy-PEP on Neisseria, and the likelihood of transferring particular genotypes across species' boundaries.

Doxycycline Postexposure Prophylaxis (DoxyPEP) for Bacterial STI Prevention

This Viewpoint describes what dermatologists should know about doxycycline postexposure prophylaxis (doxyPEP) for bacterial sexually transmitted infection (STI) prevention, specifically syphilis, chlamydia, and gonorrhea.

Impact of doxycycline post-exposure prophylaxis for sexually transmitted infections on the gut microbiome and antimicrobial resistome

Doxycycline post-exposure prophylaxis (doxy-PEP) reduces bacterial sexually transmitted infections among men who have sex with men and transgender women. Although poised for widespread clinical implementation, the impact of doxy-PEP on antimicrobial resistance remains a primary concern as its effects on the gut microbiome and resistome, or the antimicrobial resistance genes (ARGs) present in the gut microbiome, are unknown. To investigate these effects, we studied participants from the DoxyPEP trial, a randomized clinical trial comparing doxy-PEP use, a one-time doxycycline 200-mg dose taken after condomless sex (DP arm, n = 100), to standard of care (SOC arm, n = 50) among men who have sex with men and transgender women. From self-collected rectal swabs at enrollment (day-0) and after 6 months (month-6), we performed metagenomic DNA sequencing (DNA-seq) or metatranscriptomic RNA sequencing (RNA-seq). DNA-seq data were analyzable from 127 samples derived from 89 participants, and RNA-seq data were analyzable from 86 samples derived from 70 participants. We compared the bacterial microbiome and resistome between the two study arms and over time. The median number of doxycycline doses taken since enrollment by participants with DNA-seq data was zero (interquartile range (IQR): 0-7 doses) for the SOC arm and 42 (IQR: 27-64 doses) for the DP arm. Tetracycline ARGs were detected in all day-0 DNA-seq samples and in 85% of day-0 RNA-seq samples. The proportional mass of tetracycline ARGs in the resistome increased between day-0 and month-6 in DP participants from 46% to 51% in the metagenome (P = 2.3 × 10-2) and from 4% to 15% in the metatranscriptome (P = 4.5 × 10-6), but no statistically significant increases in other ARG classes were observed. Exposure to a higher number of doxycycline doses correlated with proportional enrichment of tetracycline ARGs in the metagenome (Spearman's ρ = 0.23, P = 9.0 × 10-3) and metatranscriptome (Spearman's ρ = 0.55, P = 3.7 × 10-8). Bacterial microbiome alpha diversity, beta diversity and total bacterial mass did not differ between day-0 and month-6 samples from DP participants when assessed by either DNA-seq or RNA-seq. In an abundance-based correlation analysis, we observed an increase over time in the strength of the correlation between tetracycline ARGs and specific bacterial taxa, including some common human pathogens. In sum, doxy-PEP use over a 6-month period was associated with an increase in the proportion of tetracycline ARGs comprising the gut resistome and an increase in the expression of tetracycline ARGs. At 6 months of doxy-PEP use, no residual differences were observed in alpha and beta diversity or taxonomic composition of the gut microbiome. As doxy-PEP is implemented as a public health strategy, further studies and population-level surveillance of doxycycline-resistant pathogens are needed to understand the implications of these findings. ClinicalTrials.gov registration number: NCT03980223 .

Lyme disease chemoprophylaxis prescribing before and after pharmacist prescriptive authority in Nova Scotia

Background

Lyme disease is a bacterial infection transmitted to humans through bites from infected Ixodes species of ticks. Prophylaxis with a single dose of oral doxycycline following a bite from an infected tick reduces the risk of developing Lyme disease. Pharmacists in Nova Scotia (NS) were among the first in Canada to prescribe for this indication. The primary objective of this study is to describe experiences with pharmacist prescribing of prophylaxis after tick bites in NS.

Methods

A retrospective cohort study was performed using health administrative data 16 months before and after pharmacists were authorized to prescribe Lyme disease chemoprophylaxis (August 1, 2021). All dispensations of a single dose of oral doxycycline from a community pharmacy in NS were included. Data collected included prescriber type, date, and county of dispensation. Comparisons of dispensations were completed before and after pharmacists gained prescriptive authority and relative to other prescribers. Dispensations were described descriptively.

Results

Over the study period, 12,549 single-dose doxycycline prescriptions were dispensed in NS: 3900 prescriptions were dispensed before pharmacist prescribing authorization for this indication occurred and 8649 were dispensed after. Pharmacists prescribed 61.3% of all single-dose doxycycline prescriptions following implementation of prescribing authority.

Discussion

An increase in single-dose doxycycline prescriptions was observed in NS. Pharmacists have become the primary prescribers for Lyme disease chemoprophylaxis in the province.

Conclusion

Patients were willing to be assessed for chemoprophylaxis after tick exposure by pharmacists, and pharmacist prescribing for this indication suggests increased access to post-tick exposure care.

Update on HIV Chemoprevention

Despite rapid advances in the field of HIV prevention and treatment, unacceptably high global HIV incidence rates highlight the ongoing need for effective HIV prevention interventions for populations at risk for HIV acquisition. This article provides an updated review of the current data surrounding HIV prevention strategies, including treatment as prevention (TasP), preexposure prophylaxis (PrEP), and postexposure prophylaxis (PEP), as well as advances in sexually transmitted infection biomedical prevention. This review provides an overview of the multiple PrEP modalities that are available globally, such as oral PrEP, injectable cabotegravir, and the dapivirine vaginal ring, and describes their respective clinical trials, efficacies, and regulatory approvals. We also discuss ongoing research into novel PrEP agents, such as broadly neutralizing antibodies, and efforts toward HIV vaccine development.

Knowledge, uptake and intention to use antibiotic post-exposure prophylaxis and meningococcal B vaccine (4CMenB) for gonorrhoea among a large, online community sample of men and gender-diverse individuals who have sex with men in the UK

Novel STI prevention interventions, including doxycycline post-exposure prophylaxis (doxyPEP) and meningococcal B vaccination (4CMenB) against gonorrhoea, have been increasingly examined as tools to aid STI control. There is evidence of the efficacy of doxyPEP in preventing bacterial STIs; however, limited data exist on the extent of use in the UK. We examined self-reported knowledge and use of antibiotic post-exposure prophylaxis (PEP), and intention to use (ITU) doxyPEP and 4CMenB among a large, community sample of men and gender-diverse individuals who have sex with men in the UK. Using data collected by the RiiSH survey (November/December 2023), part of a series of online surveys of men and other gender-diverse individuals in the UK, we describe (%, [95% CI]) self-reported knowledge and use of antibiotic PEP (including doxyPEP) and doxyPEP and 4CMenB ITU. Using bivariate and multivariable logistic regression, we examined correlates of ever using antibiotic PEP, doxyPEP ITU, and 4CMenB ITU, respectively, adjusting for sociodemographic characteristics and a composite marker of sexual risk defined as reporting (in the last three months): ≥5 condomless anal sex partners, bacterial STI diagnosis, chemsex, and/or meeting partners at sex-on-premises venues, sex parties, or cruising locations. Of 1,106 participants (median age: 44 years [IQR: 34-54]), 34% (30%-37%) knew of antibiotic PEP; 8% (6%-10%) ever reported antibiotic PEP use. Among those who did, most reported use in the last year (84%, 73/87) and exclusively used doxycycline (69%, 60/87). Over half of participants reported doxyPEP ITU (51% [95% CI: 47%-56%], 568/1,106) while over two-thirds (64% [95% CI: 60%-69%], 713/1,106) reported 4CMenB ITU. Participants with markers of sexual risk and with uptake of other preventative interventions were more likely to report ever using antibiotic PEP as well as doxyPEP and 4CMenB ITU, respectively. HIV-PrEP users and people living with HIV (PLWHIV) were more likely to report antibiotic PEP use and doxyPEP and 4CMenB vaccination ITU than HIV-negative participants not reporting recent HIV-PrEP use. Findings demonstrate considerable interest in the use of novel STI prevention interventions, more so for 4CMenB vaccination relative to doxyPEP. Fewer than one in ten participants had reported ever using antibiotic PEP, with most using appropriate, evidence-based antibiotics. The use of antibiotic PEP and the report of doxyPEP ITU and 4CMenB ITU was more common among those at greater risk of STIs.

From Cure to Prevention: Doxycycline's Potential in Prophylaxis for Sexually Transmitted Infections

Over the past two decades, the global incidence of sexually transmitted infections (STIs) such as gonorrhea, chlamydia, and syphilis have increased significantly, particularly among cisgender men who have sex with men (MSM) and transgender women (TGW). This rise in STIs has spurred interest in new preventive measures, including doxycycline post-exposure prophylaxis (DoxyPEP). Clinical trials in the United States and France have demonstrated the effectiveness of DoxyPEP in reducing both chlamydia and syphilis incidence among MSM and TGW; although, its efficacy against gonorrhea remains limited, and it was further found to be ineffective among cisgender women in Kenya. Due to the promising results, the CDC and the German STI Society have incorporated DoxyPEP into their guidelines for specific high-risk groups. However, the broader implementation of DoxyPEP presents several challenges and ethical concerns. Key issues involve the potential development of antimicrobial resistance, particularly among common STI pathogens like C. trachomatis, M. genitalium, and N. gonorrhoeae, as well as other bacteria such as S. aureus and K. pneumoniae. Additionally, questions concerning equitable healthcare access, the potential impact on adherence to safer sex practices, and broader public health implications warrant careful consideration. Addressing these challenges necessitates a careful balance between the benefits and risks of DoxyPEP, as well as the implementation of strategies to mitigate negative outcomes while maximizing the impact on public health. Lastly, future research should explore the integration of DoxyPEP with other preventive strategies, such as vaccines, to enhance its effectiveness and reduce the global burden of STIs.

Doxycycline prophylaxis for sexually transmitted infection prevention in Vietnam: Awareness, attitudes, and willingness to use among men who have sex with men using HIV-PrEP

Objectives

Doxycycline prophylaxis shows promise for sexually transmitted infection (STI) prevention, but data primarily come from high-income countries. This study assessed awareness, willingness and factors associated with willingness to use doxycycline for STI prevention among men who have sex with men (MSM) using HIV-PrEP in Vietnam.

Methods

Between January 25 and February 4, 2024, a cross-sectional study recruited males aged ≥18 years who reported sex with men in the past 12 months from 11 PrEP clinics in Hanoi and Ho Chi Minh City. Self -administered surveys were conducted, and multivariable logistic regression was applied to identify factors associated with willingness to use doxyPEP/PrEP.

Results

Among 350 participants (45.7% Hanoi, 54.3% Ho Chi Minh City), the median age was 25 (interquartile range [IQR]: 21-30), and 10.6% self-reported an STI diagnosis in the past 12 months. In the previous 6 months, the median number of sex partners was 2 (IQR: 1-4), 53.1% reported condomless anal sex. Awareness of doxycycline was low (20.2%; 65/322), however, 75.4% (264/350) expressed willingness to use it, with 63.6% (168/264) preferring doxyPrEP. Participants who disclosed HIV-PrEP use to all sex partners (adjusted odds ratio [aOR]: 4.17; 95% confidence interval [95%CI] 1.84, 9.46), and those with higher perceived STI risk (aOR: 1.12; 95% CI 1.03, 1.22) were more likely to report willingness to use doxycycline prophylaxis. Concerns about daily medication (aOR: 0.43; 95% CI 0.24, 0.81) and fear of judgement from peers (aOR: 0.41; 95% CI: 0.21, 0.81) were associated with lower willingness.

Conclusions

Knowledge of doxyPEP/PrEP among MSM on HIV-PrEP in Vietnam was low. However, most expressed willingness to use doxycycline prophylaxis, with two-thirds preferring doxyPrEP. Findings highlight the need to disseminate information on doxyPEP/PrEP for STI prevention strategy, evaluating the usage and comparative effectiveness of doxyPEP and doxyPrEP to guide implementation efforts in Vietnam.

1 What is already known on this topic

Men who have sex with men (MSM) experience a disproportionate burden of HIV and bacterial sexually transmitted infections (STIs) worldwide, including in Vietnam. Despite the successful expansion of HIV Pre-Exposure Prophylaxis (PrEP) programs in Vietnam, bacterial STI rates remain persistently high among PrEP users, highlighting gaps in prevention efforts. Evidence from high-income countries (HICs) suggests that doxycycline prophylaxis can significantly reduce the incidence of bacterial STIs such as syphilis and chlamydia. However, little is known about the awareness, acceptability, and feasibility of doxycycline prophylaxis in Vietnam and other low-and middle-income countries (LMICs).

2 What this study adds

This study is the first to assess awareness, attitudes, and willingness to use doxycycline prophylaxis for STI prevention among MSM in Vietnam, a LMIC setting. Despite low prior awareness, the study found high willingness (75.4%) to use doxycycline, with most participants preferring daily doxyPrEP over doxyPEP. It also identified critical facilitators, such as perceived high STI risk and disclosure of HIV-PrEP use to sex partners, as well as barriers, including stigma, cost, and concerns about daily medication. These findings provide insights into the feasibility of introducing doxycycline prophylaxis in Vietnam, distinguishing it from contexts in HICs where different preferences and barriers may exist.

3 How this study might affect research practice or policy

This study provides a foundation for further research on doxycycline prophylaxis in LMICs, emphasizing the need to evaluate its real-world effectiveness and implementation in settings with high AMR prevalence. Policymakers can use these findings to develop tailored guidelines and subsidies for doxycycline prophylaxis in Vietnam, ensuring affordability and accessibility.

Use of Doxycycline and Other Antibiotics as Bacterial Sexually Transmitted Infection Prophylaxis in a US Sample of Primarily Gay and Bisexual Men

BACKGROUND

Doxycycline used as postexposure prophylaxis (doxyPEP) within 72 hours of sex reduces the risk of bacterial sexually transmitted infections (STIs) in people assigned male sex at birth. Little is known about current use of antibiotics as STI prophylaxis in US populations likely to benefit from doxyPEP.

METHODS

We conducted an online survey in September 2023 of US adults recruited via sexual networking apps used mainly by gay and bisexual men (GBM). Respondents were asked about the use of antibiotics around the time of sex to prevent bacterial STIs.

RESULTS

Of 903 respondents, most (96.2%) identified as GBM; 19.0% were living with HIV and 42.5% were using HIV preexposure prophylaxis (PrEP). Half (49.1%) had heard of using antibiotics to prevent STIs, and 95.6% were interested in use. Overall, 21.0% had used antibiotic STI prophylaxis, and 15.9% had done so in the past year. Among those reporting any use, most (78.1%) had used doxycycline; some used amoxicillin (16.7%), azithromycin (14.5%), or other antibiotics (14.1%). Among those reporting use in the past year, 46.9% used it for some, 28.1% for most, and 25.0% for all sex acts with casual partners during that period. Most (78.3%) of STI prophylaxis users reported their condom use did not change during periods of STI prophylaxis use, 17.2% indicated their condom use declined, and 4.5% indicated their condom use increased. For doxyPEP specifically, 35.7% had heard of it, and 13.0% had used it in the past year, of whom 21.0% had used a dosage other than the 200-mg dose shown to be effective.

CONCLUSIONS

In this sample of primarily GBM, interest in bacterial STI prophylaxis was nearly universal. However, some of the use was not informed by current clinical guidance or evidence from research studies. Efforts are needed to increase awareness of effective dosing and monitor real-world use.

Sexually transmitted and blood-borne infections by sex, methamphetamine use, and houselessness before, at, and after HIV diagnosis in Manitoba, Canada

Objectives

Describe the proportion of people newly living with HIV with sexually transmitted and blood-borne infections (STBBIs) before, at, and after HIV diagnosis in Manitoba, Canada.

Methods

A retrospective cohort study reviewed clinical charts of all 404 people ≥18 years old newly diagnosed with HIV in Manitoba, Canada between 2018 and 2021. Syphilis, hepatitis C and B, gonorrhea, and chlamydia infections before, at, and after HIV diagnosis were recorded and analyzed by sex at birth, injection drug use status, use of methamphetamines, and housing status.

Results

A total of 53% of people were diagnosed with syphilis, 44.1% with gonorrhea, 42.8% with chlamydia, and 40.6% with hepatitis C at least once. Among females, 64.1% had at least one or more STBBIs diagnoses before HIV diagnosis compared with 44.8% of males. Over 70% of people experiencing houselessness had at least one STBBI diagnosis before their HIV diagnosis compared with 43.9% of people not houseless. Among people who used methamphetamines, 68.3% had one or more STBBIs before HIV diagnosis compared with 28.9% of people who do not use methamphetamines. In a multivariable analysis houselessness, methamphetamine use, and younger age were associated with increased risk of any STBBIs.

Conclusions

In our Manitoba cohort of people living with HIV, disproportionately more females, people experiencing houselessness, and those who use methamphetamine were diagnosed with STBBIs. The proportion of new infections before HIV diagnoses highlights a missed opportunity to provide prevention modalities, including pre-exposure prophylaxis, and the proportion after HIV diagnosis emphasizes the importance of enhancing engagement, repeated testing, and educational strategies to ameliorate ongoing exposures.

Higher Serologic Responses of Early Syphilis to Single-dose Benzathine Penicillin G Plus Doxycycline Versus Single-dose Benzathine Penicillin G Alone Among People With HIV

BACKGROUND

Single-dose benzathine penicillin G (BPG) is the preferred therapy for early syphilis, but poorer serologic responses have been observed among people with human immunodeficiency virus (PWH). No enhanced regimen has previously been shown to improve serologic outcomes of early syphilis.

METHODS

We conducted a retrospective study to compare the treatment responses to single-dose BPG combined with 7-day doxycycline versus BPG alone in PWH who presented with early syphilis. Rapid plasma reagin (RPR) titers were determined every 3-6 months for all included PWH. Serologic response was defined as at least a 4-fold decline in RPR titers at month 12.

RESULTS

During January 2018 to March 2022, 223 PWH with 307 episodes of early syphilis received single-dose BPG plus doxycycline and 347 PWH with 391 episodes received BPG alone. The median age was 36 years and baseline CD4 count was 600 cells/mm3. In the intention-to-treat with last-observation-carried-forward analysis, PWH receiving BPG plus doxycycline had a significantly higher serologic response rate at 12 months of treatment than those receiving BPG alone (79.5% vs 70.3%, respectively; P = .006). The factors associated with 12-month serologic response were RPR titer (per 1-log2 increase, adjusted odds ratio [AOR], 1.25; 95% confidence interval [CI], 1.15-1.35) and receipt of BPG plus doxycycline (AOR, 1.71; 95% CI, 1.20-2.46). In the subgroup analyses, BPG plus doxycycline was consistently associated with a better serologic response than BPG alone at month 12.

CONCLUSIONS

Among PWH with early syphilis, single-dose BPG plus doxycycline achieved higher serologic responses than BPG alone during a 12-month follow-up period.

Estimated prevalence and associations of sexually transmissible bacterial enteric pathogens in asymptomatic men who have sex with men: a systematic review and meta-analysis

OBJECTIVE

The reservoir of sexually transmissible bacterial enteric pathogens in asymptomatic men who have sex with men (MSM) may impact future outbreaks, and the evolution of antimicrobial resistance. We aimed to estimate the pooled prevalence and explore any factors associated with Shigella spp, Campylobacter spp, diarrhoeagenic Escherichia coli and Salmonella spp in asymptomatic MSM using the random effects model.

METHODS

We searched Embase, MEDLINE, CINAHL and Web of Science Core Collections for manuscripts published up to February 2024. One author screened citations and abstracts; two authors independently conducted a full-text review. We included manuscripts which measured the prevalence of Shigella spp, Campylobacter spp, diarrhoeagenic E. coli and Salmonella spp in asymptomatic MSM. Quality and risk of bias was assessed independently by two authors using the Joanna Briggs Institute critical appraisal tools. We calculated pooled prevalence and CIs using the random effects model.

RESULTS

Six manuscripts were included in the final review. The manuscripts were from Australia (n=2), the UK (n=2), the Netherlands (n=1) and the USA (n=1) and included data from 3766 asymptomatic MSM tested for bacterial enteric pathogens. The prevalence of Shigella spp was 1.1% (95% CI 0.7% to 1.7%), Campylobacter spp 1.9% (95% CI 1.5% to 2.5%), diarrhoeagenic E. coli 3.8% (95% CI 2.1% to 6.7%) and Salmonella spp 0.3% (95% CI 0.1% to 0.6%). Two manuscripts demonstrated that the detection of bacterial enteric pathogen was more frequent in asymptomatic MSM using HIV-pre-exposure prophylaxis (PrEP), living with HIV, reporting <5 new sexual partners in the past 3 months, reporting insertive oral-anal sex and group sex compared with MSM testing negative.

CONCLUSION

Despite a small number of manuscripts, this review has estimated the pooled prevalence, and highlighted some possible associations with sexually transmissible bacterial enteric pathogens in asymptomatic MSM, which can inform future clinical guidelines, public health control strategies and research to increase our understanding of transmission and the evolution of antimicrobial resistance.

PROSPERO REGISTRATION NUMBER

CRD42024518700.

Review of doxycycline for prophylaxis of sexually transmitted infections

The surging rates of STIs necessitate medical practitioners in the appropriate specialties to focus on rapid recognition, treatment and prevention of these conditions. Through both pre- and post-exposure prophylaxis with doxycycline, dermatologists can provide up-to-date treatment in the field of venereology. Herein, we review the results of clinical trials in the available literature that investigate doxycycline prophylaxis in the prevention of bacterial STIs. A search was performed using the PubMED and Scopus databases which yielded six clinical trials for our review. Based on the results of these clinical trials, doxycycline prophylaxis offers significant reductions in bacterial STIs, specifically in men who have sex with men (MSM). Additional research is needed in other high-risk groups, including females. Moreover, additional research is needed to determine the effects of doxycycline prophylaxis on tetracycline resistance in STI-causing bacteria. As the utilization of doxycycline prophylaxis for STIs becomes more common, it is important that dermatologists become familiar with the data surrounding this prevention regimen and patient populations who may seek to know more about it. More research is needed to determine benefits in other subpopulations, antimicrobial resistance and cost effectiveness.

ChatGPT as a tool to improve access to knowledge on sexually transmitted infections

OBJECTIVES

Specific to sexual health, individuals in need of information may be adolescents who have limited ability to formally access healthcare. These digital natives may turn to ChatGPT to address their concerns on sexually transmitted infections (STI). We sought to evaluate the veracity of ChatGPT's responses to commonly asked questions on STIs.

METHODS

We instructed ChatGPT (GPT 3.5) to answer STI questions from three domains, namely, (1) general risk factors for STIs, (2) access to care and diagnosis of STIs and (3) management of STIs and postexposure prophylaxis. The responses were recorded and checked against the US Centers for Disease Control and Prevention STI Treatment Guidelines 2021.

RESULTS

Overall, the responses were concise and accurate. In terms of prevention, ChatGPT could also recommend measures like safe sex practices and human papillomavirus vaccination. However, it failed to recommend HIV pre-exposure prophylaxis. When an individual expressed a symptom that could potentially represent STI (eg, dyspareunia) ChatGPT appropriately provided reassurance that other possibilities exist, but advocated for testing. In terms of treatment, ChatGPT consistently communicated the importance of partner testing and follow-up testing, but at times, failed to highlight the importance of testing for other STIs. Overall, the advice given was not tailored to the specific individual's circumstances.

CONCLUSIONS

ChatGPT can provide helpful information regarding STIs, but the advice lacks specificity and requires a human physician to fine-tune. Its ubiquity may make it a useful adjunct to sexual health clinics, to improve knowledge and access to care.

IUSTI Europe position statement on use of DoxyPEP: June 2024

This position statement is aimed at front-line clinical practitioners and public health authorities in WHO European Region providing services for people wishing to reduce their risk of acquiring sexually transmitted infections (STIs), including HIV.

Trends in Sexually Transmitted Infections Associated With the Doxycycline Postexposure Prophylaxis Guidelines in San Francisco

ABSTRACT

The San Francisco Department of Public Health was the first to issue guidance on the use of doxycycline for postexposure prophylaxis against sexually transmitted infections in at-risk populations. We investigated the association between the issuance of these guidelines and rates of male rectal chlamydia, male rectal gonorrhea, and adult male syphilis.

Breakthrough Rectal Neisseria gonorrhoeae Infections After Meningococcal B Vaccination: Microbiological and Clinical Features

Background

4CMenB appears to be effective in reducing Neisseria gonorrhoeae (Ng) infections. Aims are to assess factors associated with breakthrough rectal Ng after 4CMenB and evaluate clinical and microbiological characteristics of breakthrough infections compared with before vaccination.

Methods

This was a retrospective study of gay, bisexual, and other men who have sex with men (GBMSM) vaccinated with 4CMenB (2 doses) between 2017 and 2023 at the San Raffaele Scientific Institute for Research, Hospitalization and Healthcare (IRCCS San Raffaele Scientific Institute), Milan, Italy, and tested for rectal Ng. Rectal Ng infection is considered breakthrough if it occurs >1 month after the second 4CMenB dose and with positive nucleic acid amplification test (NAAT) result. Follow-up was from July 2017 (first 4CMenB vaccination) to November 2023 (data freeze). Rectal Ng was screened with both NAAT and gonococcal-specific cultures. Characteristics of individuals with or without breakthrough Ng and of Ng infections before or after 4CMenB were compared using Mann-Whitney and χ2/Fisher tests.

Results

Overall, 473 GBMSM vaccinated with 4CMenB were included, with a median age (interquartile range) of 43 (37-51) years; 451 of 473 were living with human immunodeficiency virus. The percentage of NAAT-positive rectal Ng swab samples was 76 of 957 (7.7%) after 4CMenB and 51 of 456 (11.1%) before. Breakthrough rectal Ng after baseline were 76 in 57 of 473 people. People with rectal Ng after 4CMenB were younger, more likely to have a previous sexually transmitted infection, and had more sexual partners than those without (all P < .001). Breakthrough rectal Ng infections were less frequently symptomatic (34.2% vs 66.7%; P = .001) and more likely with negative gonococcal-specific culture (55.3% vs 19.6%; P < .001) compared with before vaccination.

Conclusions

Breakthrough rectal Ng infections after 4CMenB were 76 in 57/473 people, preferentially identified in GBMSM with higher-risk sexual behaviors, were less often symptomatic, and more often with negative gonococcal-specific cultures, suggesting lower infection virulence.

Ulcerative erythematous papules and plaques on the face and lower legs of a man living with HIV: a clinicopathological challenge

A 44-year-old male presented with a 2-month history of erythematous ulcerative papules and plaques on the scalp, face, and bilateral lower legs. He had a 5-year history of well-controlled HIV on antiretroviral therapy and recurrent syphilis infections. His face had violaceous plaques, while bilateral ankles and calves had ulcerative lesions with necrotic centers and purple borders. The morphologies clinically mimicked pyoderma gangrenosum on the lower extremities and cutaneous lymphoma on the face. Biopsy and reactive rapid plasma reagin confirmed a diagnosis of lues maligna, and the patient was successfully treated with penicillin G benzathine.

Syphilis Positivity Among Men Who Have Sex With Men With Direct, Indirect, and No Linkage to Female Sex Partners: Exploring the Potential for Sex Network Bridging in Baltimore City, MD

BACKGROUND

Syphilis epidemics among women and men who have sex with men (MSM) may be connected, but these connections are poorly understood. Using egocentric network data from a US urban MSM cohort, we examined sociodemographics, behaviors, and syphilis positivity among MSM with (1) direct (MSM who report sex with women, MSMW); (2) indirect (MSM who only report male partners, some of whom are MSMW, MSMO/W); and (3) no (MSM who only report male partners and whose partners only have sex with men, MSMO/O) connection to women.

METHODS

Sexually active MSM aged 18 to 45 years were administered behavioral and network interviews (recall period: 3 months) and syphilis/HIV testing. Syphilis positivity was defined as rapid plasma reagin titer ≥1:8. Modified Poisson regression was used to test for differences across groups.

RESULTS

Among 385 MSM, 14.5% were MSMW and 22.3% were MSMO/W. MSMW and MSMO/W were significantly more likely than MSMO/O to report sex behaviors associated with increased syphilis acquisition/transmission risk, including ≥2 sex partners (MSMW: adjusted prevalence ratio [aPR], 1.28 [0.98-1.68]; MSMO/W: aPR, 1.35 [1.09-1.69]) and concurrent sex partners (MSMW: aPR, 1.50 [1.17-1.92]; MSMO/W: aPR, 1.39 [1.11-1.74]), and for MSMW only, transactional sex (aPR, 2.07 [1.11-3.88]). Syphilis positivity was 16.4% and was lower among MSMW (9.4%) and MSMO/W (14.1%) than MSMO/O (18.5%), but differences were not significant.

CONCLUSIONS

There may be considerable connectivity between MSM and female sex partners that could facilitate syphilis transmission, and behaviors that increase acquisition/transmission risk among MSMW and MSMO/W may be distinct from MSMO/O. Future work should focus on examining the context and temporal patterns of sex partnerships among MSMW and MSMO/W.

Sexually Transmitted Infections in Transgender and Gender-Diverse Individuals: Review of Screening and Treatment Recommendations

Transgender and gender-diverse individuals experience disproportionately high rates of sexually transmitted infections (STIs). In this review, the authors discuss the epidemiology, screening recommendations, and treatment guidelines for STIs in transgender and gender-diverse people.

Effects of doxycycline post-exposure prophylaxis for prevention of sexually transmitted infections on gonorrhoea prevalence and antimicrobial resistance among men who have sex with men in the USA: a modelling study

BACKGROUND

Doxycycline post-exposure prophylaxis (PEP) has been shown to be efficacious for the prevention of bacterial sexually transmitted infections, but resistance implications for Neisseria gonorrhoeae remain unknown. We aimed to use a mathematical model to investigate the anticipated impact of doxycycline PEP on the burden of gonorrhoea and antimicrobial resistance dynamics in men who have sex with men (MSM) in the USA.

METHODS

Using a deterministic compartmental model, characterising gonorrhoea transmission in a US MSM population comprising three sexual activity groups defined by annual partner turnover rates, we introduced doxycycline PEP at various uptake levels (10-90%) among those with high sexual activity. Infections were stratified by symptom status and resistance profile (ie, susceptible, ceftriaxone-resistant, tetracycline-resistant, or dual-resistant), with ceftriaxone the treatment for active infection. As resistance to tetracycline, not doxycycline, is monitored and reported nationally, we used this as a proxy for doxycycline PEP resistance. We compared the 20-year prevalence, incidence rates, and cumulative incidence of gonococcal infection, resistance dynamics (time to 5% prevalence of ceftriaxone resistance, 5% prevalence of dual resistance, and 84% prevalence of tetracycline resistance), and antibiotic consumption with baseline (ie, no doxycycline PEP).

FINDINGS

Uptake of doxycycline PEP resulted in substantial reductions in the prevalence and incidence of gonorrhoea, but accelerated the spread of tetracycline resistance. The maximum reduction in prevalence over 20 years compared with no uptake ranged from 40·3% (IQR 15·3-83·4) with 10% doxycycline PEP uptake to 77·4% (68·4-84·9) with 90% uptake. Similarly, the maximum reduction in the incidence rate ranged from 38·6% (14·1-83·6) with 10% uptake to 77·6% (68·1-84·7) with 90% uptake. Cumulative gonococcal infections were reduced by a median of 14·5% (IQR 8·4-21·6) with 10% uptake and up to 46·2% (26·5-59·9) with 90% uptake after 5 years, and by 6·5% (3·4-13·0) with 10% uptake and 8·7% (4·3-36·2) with 90% uptake by 20 years. In almost all scenarios explored, doxycycline PEP lost clinical effectiveness (defined as 84% prevalence of tetracycline resistance) within the 20-year period, but its lifespan ranged from a median of 12·1 years (IQR 9·9-15·7) with 10% uptake to 1·6 years (1·3-1·9) with 90% uptake. Doxycycline PEP implementation had minimal impact on extending the clinical lifespan of ceftriaxone monotherapy (5·0 years [IQR 4·0-6·2]), with the median time to 5% prevalence of resistance ranging from 4·8 years (3·9-6·0) for 90% uptake to 5·0 years (4·1-6·2) for 10% uptake. Similarly, the median time to 5% prevalence of dual resistance to ceftriaxone and tetracycline ranged from 4·8 years (3·9-6·0) for 90% uptake to 5·8 years (4·8-7·4) for 10% uptake. Median decrease in ceftriaxone consumption for high doxycycline PEP uptake levels compared with baseline ranged from 41·7% (27·0-54·3) for 50% uptake to 50·2% (29·3-62·7) for 90% uptake at 5 years, but dropped to 11·8% (6·9-32·0) for 50% uptake and 12·1% (7·0-41·6) for 90% uptake after 20 years.

INTERPRETATION

Notwithstanding the clear benefits of doxycycline PEP for other sexually transmitted infections, for N gonorrhoeae, model findings suggest that doxycycline PEP is an effective but impermanent solution for reducing infection burden, given eventual selection for resistant strains. This finding presents a challenge for policy makers considering strategies for doxycycline PEP implementation and oversight: the need to balance the clear, short-term clinical benefits with the risk of harm via antimicrobial resistance.

FUNDING

US Centers for Disease Control and Prevention, National Institute of Allergy and Infectious Diseases.

Syphilitic Hepatitis: An Uncommon Manifestation of Secondary Syphilis

Syphilitic hepatitis is a rare manifestation of a sexually transmitted infection. Given its nonspecific presentation, it is important for clinicians to consider the diagnosis in sexually active patients presenting with elevated liver tests.  In this case, a 30-year-old man presented with an itchy rash and was diagnosed with an allergic reaction. He returned to the clinic one week later with a worsening rash. A sexual history was obtained, which led to sexually transmitted disease testing. Laboratory evaluation revealed a positive syphilis serology. A diagnosis of secondary syphilis was made, and he was treated with penicillin. The following day, he presented to the emergency department complaining of worsening rash, abdominal pain, and fever. Laboratory evaluation was significant for elevated transaminases. He received supportive care and was advised to follow up with his primary care provider. One month after his initial presentation, he presented to the clinic with resolution of the rash. Laboratory evaluation revealed a fourfold decrease in rapid plasma reagin titer and improvement in liver enzymes. The transaminitis work-up was unremarkable, and the liver tests ultimately normalized. A diagnosis of syphilitic hepatitis was made. A comprehensive detailed sexual history is important and key to the diagnosis of syphilitic hepatitis. Long-term sequelae are rare. Syphilitic hepatitis is a curable condition and should remain in the differential diagnosis in all sexually active persons presenting with abnormal liver enzymes.

Doxycycline Post-Exposure Prophylaxis for Bacterial Sexually Transmitted Infections: The Current Landscape and Future Directions

PURPOSE OF REVIEW

The incidence of bacterial sexually transmitted infections (STI) continues to rise particularly among men who have sex with men (MSM). Doxycycline post-exposure prophylaxis (doxy-PEP) has emerged as a promising biomedical prevention strategy. This review aims to summarize the results of recent studies, highlight the current normative guidance on the use of doxy-PEP, and discuss remaining questions.

RECENT FINDINGS

In the past decade, there have been four randomized controlled trials and three real-world analyses of doxy-PEP, which consistently demonstrated a reduction in Chlamydia trachomatis and Treponema pallidum infections among MSM. Questions remain regarding the efficacy of doxy-PEP for Neisseria gonorrhoeae infection and among cisgender women. Possible detrimental impacts include an increase in antimicrobial resistance as well as alterations to the gut microbiome Doxy-PEP is an effective strategy for preventing Chlamydia trachomatis and Treponema pallidum among MSM. Further work is needed to investigate the benefits among other populations, as well as to monitor for adverse effects.

Revealing the Genetic Diversity of Chinese Chlamydia trachomatis Strains Directly From Clinical Samples Through Selective Whole Genome Amplification

BACKGROUND

Chlamydia trachomatis is the causative agent of the most prevalent bacterial sexually transmitted infections globally. Whole genome sequencing is essential for molecular Chlamydia surveillance; however, its application is hampered by the pathogen's low abundance in clinical specimens and the expensive labor-intensive nature of existing enrichment methodologies for Chlamydia.

METHODS

We developed a targeted whole genome amplification tool termed SWITCH by integrating phi29 DNA polymerase-mediated amplification with meticulously designed primer sets to enrich the C trachomatis genome, followed by whole genome sequencing. This method underwent evaluation through testing synthetic and clinical specimens.

RESULTS

SWITCH demonstrated robust ability to achieve up to 98.3% genomic coverage of C trachomatis from as few as 26.4 genomic copies present in synthetic specimens, and it exhibited excellent performance across diverse C trachomatis serovars. Utilizing SWITCH, we directly generated 21 Chlamydia genomes from 26 clinical samples, enabling us to gain insights into the genetic relationships and phylogeny of current Chlamydia strains circulating in the country. Remarkably, this study marked the first instance of generating Chinese Chlamydia genomes directly from clinical samples.

CONCLUSIONS

SWITCH represents a practical cost-efficient approach to enrich the Chlamydia genome directly from clinical specimens, offering an efficient avenue for molecular surveillance of Chlamydia.

Bacterial sexually transmitted infections among men who have sex with men and transgender women using oral pre-exposure prophylaxis in Latin America (ImPrEP): a secondary analysis of a prospective, open-label, multicentre study

BACKGROUND

The global burden of sexually transmitted infections (STIs) poses a challenge in the context of HIV pre-exposure prophylaxis (PrEP) programmes. We aimed to explore factors associated with prevalent, incident, and recurrent STIs in men who have sex with men (MSM) and transgender women on PrEP in Brazil, Mexico, and Peru.

METHODS

ImPrEP was a prospective, single-arm, open-label, multicentre study that enrolled MSM and transgender women in the context of the public health systems of Brazil (14 sites), Mexico (four sites), and Peru (ten sites) between February, 2018, and June, 2021. Eligibility criteria followed regional PrEP guidelines at the study start, including participants aged 18 years and older, not living with HIV, and reporting at least one of the following in the previous 6 months: condomless anal sex (CAS), anal sex with partner(s) living with HIV, any bacterial STI, or transactional sex. Eligible participants were screened and enrolled on the same day to receive daily oral PrEP (tenofovir disoproxil fumarate 300 mg and emtricitabine 200 mg). We assessed three outcomes: prevalent bacterial STIs, incident bacterial STIs, and recurrent bacterial STIs. Testing occurred at baseline and quarterly for syphilis, anorectal chlamydia, and anorectal gonorrhoea. Behavioural data were collected at baseline and quarterly. The study was registered with the Brazilian Registry of Clinical Trials, U1111-1217-6021.

FINDINGS

Among all 9509 participants included in the ImPrEP study (3928 [41·3%] in Brazil, 3288 [34·6%] in Mexico, and 2293 [24·1%] in Peru), 8525 (89·7%) had available STI results at baseline and were included in the prevalent STI analysis, and 7558 (79·5%) had available STI results during follow-up and were included in the incident and recurrent STI analyses. 2184 (25·6%) of 8525 participants had any bacterial STI at baseline. STI incidence during follow-up was 31·7 cases per 100 person-years (95% CI 30·7-32·7), with the highest rate for anorectal chlamydia (11·6 cases per 100 person-years, 95% CI 11·0-12·2), followed by syphilis (10·5 cases per 100 person-years, 9·9-11·1) and anorectal gonorrhoea (9·7 cases per 100 person-years, 9·2-10·3). Although only 2391 (31·6%) of 7558 participants had at least one STI during follow-up, 915 (12·1%) participants had recurrent diagnoses, representing 2328 (61·2%) of 3804 incident STI diagnoses. Characteristics associated with prevalent, incident, and recurrent STIs included younger age, multiple sex partners, receptive CAS, substance use, and previous STI diagnoses at baseline (incident or recurrent only).

INTERPRETATION

Our findings underscore the nuanced dynamics of STI transmission among MSM and transgender women across Latin America, highlighting an urgent need for tailored interventions to mitigate STI burden effectively, especially among the most susceptible individuals.

FUNDING

Unitaid, WHO, and ministries of health (Brazil, Mexico, and Peru).

TRANSLATIONS

For the Portuguese and Spanish translations of the abstract see Supplementary Materials section.

Doxycycline prophylaxis for the prevention of sexually transmitted infections: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVES

To investigate the effects of doxycycline pre- and post-exposure prophylaxis (doxy-PrEP/PEP) on bacterial sexually transmitted infections (STIs) by conducting a systematic review and meta-analysis.

METHODS

PubMed, Embase, and CENTRAL were searched for randomized controlled trials (RCTs), including ongoing studies published until November 7, 2023. Our primary endpoint was the incidence of bacterial STIs measured as the number of visits with an STI per total number of visits. Random-effects model was used to estimate pooled effect sizes. The study was registered with PROSPERO, CRD42023478486.

RESULTS

We identified six eligible studies containing data from seven articles and four conference abstracts, enrolling men who have sex with men (MSM), transgender women (TGW), and cisgender women (CGW). The pooled analysis of 1,766 participants with 602 newly diagnosed STIs showed a 56% decrease in the overall STI incidence using doxy-PrEP/PEP (RR = 0.44; 95% CI: 0.30-0.65; I2 = 73%). For doxy-PEP, including MSM and TGW only, the RR observed for overall STI incidence was 0.40 (95% CI: 0.28-0.57; I² = 37%), 0.19 (95% CI: 0.08-0.44; I² = 39%) for chlamydia, 0.23 (0.14-0.36; I² = 0%) for syphilis and 0.55 (95% CI: 0.34-0.87; I² = 41%) for gonorrhea. No serious adverse events were reported in the studies. The certainty of evidence regarding the efficacy of doxy-PEP among MSM and TGW was graded as high.

CONCLUSION

Doxy-PEP significantly reduces the number of new cases of chlamydia and syphilis and is potentially effective against gonorrhea, influenced by local resistance patterns. Thus, it is a promising tool in the prevention of bacterial STIs among MSM and TGW.

Syphilis testing, incidence, and reinfection among gay and bisexual men in Australia over a decade spanning HIV PrEP implementation: an analysis of surveillance data from 2012 to 2022

Background

Gay and bisexual men (GBM) remain overrepresented among syphilis diagnoses in Australia and globally. The extent to which changes in sexual networks associated with HIV pre-exposure prophylaxis (PrEP) and treatment as prevention (TasP) may have influenced syphilis transmission among GBM at the population-level is poorly understood. We describe trends in syphilis testing and incidence among GBM in Australia over eleven years spanning widespread uptake of HIV PrEP and TasP.

Methods

We analysed linked clinical data from GBM aged 16 years or older across a sentinel surveillance network in Australia from January 1, 2012, to December 31, 2022. Individuals with at least two clinic visits and with at least two syphilis tests during the observations period were included in testing and incidence analyses, respectively. Annual rates of testing and infectious syphilis incidence from 2012 to 2022 were disaggregated by HIV status and PrEP use (record of PrEP prescription; retrospectively categorised as ever or never-PrEP user). Cox regression explored associations between demographics, PrEP use and history of bacterial sexually transmissible infections (STIs) and infectious syphilis diagnosis.

Findings

Among 129,278 GBM (mean age, 34.6 years [SD, 12.2]) included in testing rate analyses, 7.4% were living with HIV at entry and 31.1% were prescribed PrEP at least once during the study period. Overall syphilis testing rate was 114.0/100 person-years (py) and highest among GBM with HIV (168.4/100 py). Syphilis testing increased from 72.8/100 py to 151.8/100 py; driven largely by increases among ever-PrEP users. Among 94,710 GBM included in incidence analyses, there were 14,710 syphilis infections diagnosed over 451,560 person-years (incidence rate = 3.3/100 py). Syphilis incidence was highest among GBM with HIV (6.5/100 py), followed by ever-PrEP users (3.5/100 py) and never-PrEP users (1.4/100 py). From 2012 to 2022, syphilis incidence increased among ever-PrEP users from 1.3/100 py to 5.1/100 py, and fluctuated between 5.4/100 py and 6.6/100 py among GBM with HIV. In multivariable Cox regression, previous syphilis diagnosis (adjusted hazard ratio [aHR] = 1.98, 95% CI = 1.83-2.14), living with HIV (aHR = 1.83, 95% CI = 1.12-1.25) and recent (past 12 m) prescription of PrEP (aHR = 1.78, 95% CI = 1.61-1.97) were associated with syphilis diagnosis.

Interpretation

Syphilis trends between GBM with HIV and GBM with evidence of PrEP use have converged over the past decade in Australia. Our findings recommend targeting emergent syphilis control strategies (e.g. doxycycline post-exposure prophylaxis) to GBM with prior syphilis diagnoses, using HIV PrEP or who are living with HIV.

Funding

Australian Department of Health and Aged Care, National Health and Medical Research Council.

Doxycycline prophylaxis and meningococcal group B vaccine to prevent bacterial sexually transmitted infections in France (ANRS 174 DOXYVAC): a multicentre, open-label, randomised trial with a 2 × 2 factorial design

BACKGROUND

Increased rates of sexually transmitted infections (STIs) are reported among men who have sex with men (MSM) and new interventions are needed. We aimed to assess whether post-exposure prophylaxis (PEP) with doxycycline could reduce the incidence of chlamydia or syphilis (or both) and whether the meningococcal group B vaccine (4CMenB) could reduce the incidence of gonorrhoea in this population.

METHODS

ANRS 174 DOXYVAC is a multicentre, open-label, randomised trial with a 2 × 2 factorial design conducted at ten hospital sites in Paris, France. Eligible participants were MSM aged 18 years or older, HIV negative, had a history of bacterial STIs within the 12 months before enrolment, and who were already included in the ANRS PREVENIR study (a cohort of MSM using pre-exposure prophylaxis with tenofovir and emtricitabine for HIV prevention). Participants were randomly assigned (2:1) to doxycycline PEP (two pills of 100 mg each orally within 72 h after condomless sex, with no more than three doses of 200 mg per week) or no PEP groups and were also randomly assigned (1:1) to the 4CMenB vaccine (GlaxoSmithKline, Paris, France; two intramuscular injections at enrolment and at 2 months) or no vaccine groups, using a computer-generated randomisation list with a permuted fixed block size of four. Follow-up occurred for at least 12 months (with visits every 3 months) up to 24 months. The coprimary outcomes were the risk of a first episode of chlamydia or syphilis (or both) after the enrolment visit at baseline for the doxycycline intervention and the risk of a first episode of gonorrhoea starting at month 3 (ie, 1 month after the second vaccine dose) for the vaccine intervention, analysed in the modified intention-to-treat population (defined as all randomly assigned participants who had at least one follow-up visit). This trial is registered with ClinicalTrials.gov, NCT04597424 (ongoing).

FINDINGS

Between Jan 19, 2021, and Sept 19, 2022, 556 participants were randomly assigned. 545 (98%) participants were included in the modified intention-to-treat analysis for the doxycycline PEP and no PEP groups and 544 (98%) were included for the 4CMenB vaccine and no vaccine groups. The median follow-up was 14 months (IQR 9-18). The median age was 40 years (34-48) and all 545 participants were male. There was no interaction between the two interventions (p≥0·1) for the primary outcome. The incidence of a first episode of chlamydia or syphilis (or both) was 8·8 per 100 person-years (35 events in 362 participants) in the doxycycline PEP group and 53·2 per 100 person-years (80 events in 183 participants) in the no PEP group (adjusted hazard ratio [aHR] 0·17 [95% CI 0·12-0·26]; p<0·0001). The incidence of a first episode of gonorrhoea, starting from month 3 was 58·3 per 100 person-years (103 events in 274 participants) in the 4CmenB vaccine group and 77·1 per 100 person-years (122 events in 270 participants) in the no vaccine group (aHR 0·78 [95% CI 0·60-1·01]; p=0·061). There were no deaths during the study. One drug-related serious adverse event (fixed-drug eruption) occurred in the doxycycline PEP group. Six (2%) participants in the doxycycline group discontinued doxycycline PEP because of gastrointestinal adverse events.

INTERPRETATION

Doxycycline PEP strongly reduced the incidence of chlamydia and syphilis in MSM, but we did not show efficacy of the 4CmenB vaccine for gonorrhoea. Doxycycline PEP should be assessed in other populations, such as heterosexual men and women, and its effect on antimicrobial resistance carefully monitored.

FUNDING

ANRS Maladies Infectieuses Emergentes.

TRANSLATION

For the French translation of the abstract see Supplementary Materials section.

Providing adolescent-friendly sexually transmitted infection screening and treatment services

PURPOSE OF REVIEW

There are high rates of sexually transmitted infections (STIs) worldwide. Adolescents and young adults (AYA) ages 15-24 years remain one of the populations that is most vulnerable to STIs. The goal of this review is to summarize recent international updates in adolescent STI screening and treatment.

RECENT FINDINGS

Normalizing sexual history taking and STI testing, and advocating for adolescents to receive comprehensive sexuality education improves stigma surrounding sexual health. The global rise in syphilis is pervasive and includes high rates of infection among AYA and women of reproductive age - universal screening may be indicated depending on local epidemiology. Gonococcal antimicrobial resistance remains a significant public health concern worldwide, thus judicious use of antimicrobials and reporting cases of resistance is crucial. Sexual health services are increasingly using virtual platforms, which may be an effective strategy for STI testing and treatment among AYA.

SUMMARY

Specific areas of focus to address the STI epidemic among AYA include reducing stigma surrounding sexual health, screening, and treatment of STIs, especially with the global rise in syphilis and high rates of gonorrhea resistance, in addition to increased use of telehealth services as effective education and intervention strategies.

Common Patterns and Unique Threats in Antimicrobial Resistance as Demonstrated by Global Gonococcal Surveillance

The rapid emergence of antimicrobial-resistant strains of Neisseria gonorrhoeae threatens treatment options and control efforts. The Uniformed Services University Gonococcal Reference Laboratory and Repository of the Global Emerging Infections Surveillance Program receives isolates from several geographically distinct regions worldwide. We analyzed 962 isolates collected during 2014-2022 for genomic and phenotypic antimicrobial resistance. Resistance to antimicrobial drugs previously used for gonococcal infections was high, but of most concern were increases of resistance to currently used antibiotic drugs, such as extended-spectrum cephalosporins and the alternative antibiotic treatment gentamicin. The percentage of isolates with reduced susceptibility to ceftriaxone was 3.6%, to cefixime was 2.5%, and to gentamicin was 15.0%. Although isolates were collected from populations of limited diversity, 706 (73.4%) of isolates demonstrated novel multiantigen sequence types, and 225 (23.4%) had novel multilocus sequence types. Continued surveillance of N. gonorrhoeae is essential to monitoring the prevalence and spread of resistant organisms worldwide.

Infectious Disease Updates for Primary Care

This article summarizes the situation with public health threats for primary care patients as of early 2024 and provides updates on strategies for the prevention, diagnosis, and treatment of common infections where new treatments and vaccines are available. For flu and COVID, an update on treatment is also provided-along with pearls useful for the busy primary care provider. The authors also discuss a new treatment option for drug-resistant vulvovaginal candidiasis and provide a balanced view of the increasingly popular technique of preventing bacterial sexually transmitted infections using doxycycline after condomless sex among men who have sex with men.

Vaccine effectiveness and impact of meningococcal vaccines against gonococcal infections: A systematic review and meta-analysis

OBJECTIVES

To systematically review and synthesis the evidence of vaccine effectiveness (VE) and impact (VI) of meningococcal vaccines in preventing gonorrhoea.

METHODS

We systematically evaluated studies. Literature searches were conducted in PubMed, Embase, Cochrane Library, CINAHL, Google Scholar, clinical trial registries, and major health and immunisation conferences. Meta-analysis was performed with the DerSimonian-Laird random-effects model to estimate the pooled VE.

RESULTS

Twelve studies met the criteria for inclusion. VE of meningococcal B (MenB) outer membrane vesicle (OMV) vaccines was evaluated in nine studies, with one study evaluating a non-OMV vaccine, MenB-FHbp. The majority of studies targeted individuals aged 15-30 years. Adjusted VE for OMV vaccines against gonorrhoea ranged from 22% to 46%. MenB-FHbp did not show protection against gonorrhoea. The pooled VE estimates of OMV vaccines against any gonorrhoea infection following the full vaccine series were 33-34%. VI was assessed for 4CMenB in Canada and Australia, for VA-MENGOC-BC in Cuba; and for MenBvac in Norway. VI ranged from a 30% to 59% reduction in gonorrhoea incidence.

CONCLUSIONS

4CMenB and other MenB-OMV vaccines show moderate effectiveness against gonorrhoea. Further research is required to explore the factors associated with vaccine protection, informing more effective vaccination strategies for the management of gonococcal infections.

Sexually Transmitted Infections in People with Human Immunodeficiency Virus

Sexually transmitted infections (STIs) are more commonly seen in patients with human immunodeficiency virus (PWH). Routine sexual history taking and appropriate multisite screening practices support prompt identification and treatment of patients, which in turn reduces morbidity and spread of STIs including HIV. Nucleic acid amplification testing has high accuracy for diagnosing many of the major STIs. Diagnosis of syphilis remains complex, requiring 2 stage serologic testing, along with provider awareness of the myriad symptoms that can be attributable to this disease. Prevention through mechanisms such as vaccines and postexposure prophylaxis hold promise to reduce the burden of STIs in PWH.

An updated molecular diagnostic for surveillance of tetM in Neisseria gonorrhoeae

Doxycycline post-exposure prophylaxis (doxy-PEP) for sexually transmitted bacterial infections reduces the risk of syphilis and chlamydia, but effectiveness against gonorrhea is variable, likely attributable to varying resistance rates. As doxy-PEP is incorporated into clinical practice, an urgent unanswered question is whether increased doxycycline use will drive tetracycline-class resistance in Neisseria gonorrhoeae. Here, we report an updated RT-PCR molecular diagnostic to detect the tetM gene that confers high-level tetracycline resistance in N. gonorrhoeae.

Staphylococcus aureus Tetracycline Resistance and Co-resistance in a Doxy-PEP-Eligible Population

In Staphylococcus aureus infections in men eligible for doxycycline post-exposure prophylaxis (doxy-PEP), tetracycline non-susceptibility is more prevalent than in the overall population and is associated with resistance to trimethoprim-sulfamethoxazole and clindamycin. Doxy-PEP may select for S. aureus multi-drug resistance, underscoring the importance of surveillance.

Early adopters of doxycycline as post-exposure prophylaxis to prevent bacterial sexually transmitted infections in a real-world clinical setting

OBJECTIVES

Doxycycline as post-exposure prophylaxis (DoxyPEP) is a novel prevention approach which has demonstrated efficacy in preventing bacterial sexually transmitted infections (STIs) in men who have sex with men (MSM) and transgender women (TGW) including people who are living with HIV and those on HIV pre-exposure prophylaxis (PrEP). We evaluated patient knowledge and interest in DoxyPEP, as well as early adopters of its use.

METHODS

In 2023, patients presenting for HIV and STI services at a primary care and sexual health clinic were asked about DoxyPEP knowledge, interest and use. Bivariate and multivariate analyses were used to evaluate demographics and behaviours associated with these outcomes.

RESULTS

A total of n=421 people presented for care. Of these, 314 were MSM/TGW. Fifteen percent were Black/African-American, and 21% were Hispanic/Latino. A total of 50% of MSM/TGW had heard of DoxyPEP, 49% were interested and 18% reported prior DoxyPEP use. Having a history of STI infection ever (adjusted OR (aOR) 5.95, 95% CI 2.69 to 13.13) and in the past 12 months (aOR 2.99, 95% CI 1.56 to 5.72) were both associated with DoxyPEP use. Individuals who had ever used HIV PrEP had nearly three times the odds of ever taking DoxyPEP (aOR 2.88, 95% CI 1.56 to 5.30). There was no association between the use of DoxyPEP and race, ethnicity or HIV status.

CONCLUSIONS

Among MSM and TGW, there is already significant awareness, interest and use of DoxyPEP to prevent bacterial STIs. Public health efforts should focus on improving access and delivery of this STI prevention intervention to MSM and TGW.