Postexposure Doxycycline to Prevent Bacterial Sexually Transmitted Infections

Exceedingly high levels of tetracycline resistance in Neisseria gonorrhoeae in eight WHO Enhanced Gonococcal Antimicrobial Surveillance Programme countries in three WHO regions, 2021-2024-doxycycline post-exposure prophylaxis will unlikely impact gonorrhoea burdens

OBJECTIVES

Doxycycline post-exposure prophylaxis (doxycycline-PEP) can reduce incident cases of syphilis, chlamydia and possibly gonorrhoea especially among men who have sex with men with recent bacterial sexually transmitted infections (STIs). Owing to potential implementation of doxycycline-PEP internationally, global tetracycline/doxycycline resistance data for contemporary Neisseria gonorrhoeae isolates has become imperative. We report tetracycline resistance data for gonococcal isolates (n = 2993) from eight WHO Enhanced Gonococcal Antimicrobial Surveillance Programme (EGASP) countries in three WHO regions in 2021-2024, i.e. to estimate potential impact of doxycycline-PEP on the incident gonorrhoea cases in these WHO EGASP countries.

METHODS

WHO EGASP isolates cultured from men with urethral discharge in Cambodia (n = 482), Indonesia (n = 101), Malawi (n = 121), The Philippines (n = 843), South Africa (n = 597), Thailand (n = 250), Uganda (n = 350) and Vietnam (n = 249) in 2021-2024 were examined. MICs (mg/L) of tetracycline were determined using Etest.

RESULTS

The tetracycline resistance (range) using the current EUCAST (MIC > 0.5 mg/L) and CLSI (MIC > 1 mg/L) clinical resistance breakpoints in the eight WHO EGASP countries was 92.2% (83.5%-99.6%) and 80.6% (66.3%-98.6%), respectively. Using a previous minocycline-PEP resistance breakpoint (MIC > 2 mg/L) and breakpoint for high-level plasmid (tetM)-mediated tetracycline resistance (MIC > 8 mg/L), the tetracycline resistance (range) was 77.3% (47.4%-98.6%) and 74.3% (31.3%-98.6%), respectively.

CONCLUSIONS

The exceedingly high levels of gonococcal tetracycline resistance (independent of resistance breakpoint used) in the eight WHO EGASP countries elucidate that doxycycline-PEP will unlikely significantly reduce the gonorrhoea cases in these countries. Furthermore, doxycycline-PEP might rapidly select for additional gonococcal strains with tetracycline resistance (low- and high-level) and MDR/XDR strains, i.e. because these strains are mostly resistant to tetracycline.

The continuing evolution of antibiotic resistance in Neisseria gonorrhoeae: past, present and future threats to effective treatment

Gonorrhoea constitutes a global public health threat. Although a range of antibiotics have been available to treat gonococcal infections for more than 80 years, Neisseria gonorrhoeae has shown remarkable versatility in its ability to develop resistance to successive classes of drugs. As a result, national and international treatment guidelines have had to be regularly updated to take account of increases in the prevalence of gonococcal strains resistant to recommended antibiotics. Even when particular antibiotics are no longer empirically used to treat gonorrhoea, N. gonorrhoeae often retains resistance, with strains becoming MDR over time. Future efforts to ensure gonorrhoea remains a treatable infection will require a multidisciplinary global approach including efforts to provide widely available and affordable diagnostic testing, robust international surveillance of resistance, and the development of new antibiotics coupled with enhanced antimicrobial stewardship to ensure optimal use of both new and older antimicrobial agents.

Severe Sexually Transmitted Infections: Neurosyphilis, Mpox, and the Tubo-ovarian Abscess

Most sexually transmitted infections (STIs) are rarely seen by medical providers as life-threatening or as a source of severe sequelae. Human immunodeficiency virus and syphilis screening are still not universal and are affected by provider and patient misconceptions. We chose to discuss 3 STIs that can lead to significant morbidity and even mortality: neurosyphilis, due to its resurgence in the past years, Mpox due to its changing epidemiology and clinical presentation, and tubo-ovarian abscess due to its huge impact on female fertility and morbidity in general.

2025 European guideline on the management of Chlamydia trachomatis infections

Sexually transmitted Chlamydia trachomatis infections remain common globally and most frequently are asymptomatic. The 2025 European C. trachomatis guideline provides up-to-date guidance regarding indications for testing and treatment of C. trachomatis infections. It includes advice on urogenital and extragenital C. trachomatis testing including the use of self-collected specimens; recommendation to use only validated NAATs for diagnosis; and recommendation to treat all C. trachomatis infections with doxycycline as first line in preference to single-dose azithromycin regimens. The absence of evidence and limited value of broad screening in asymptomatic populations for C. trachomatis infections is also discussed.

Recurrent Gonococcemia Reveiling X-linked Properdin Deficiency: A Novel Case Report

We present a unique case involving a patient who was diagnosed with X-linked properdin deficiency after 2 episodes of disseminated gonococcal infections 1 year apart. Although this deficiency is well-documented for its association with meningococcemia, its correlation with disseminated gonococcal infections (DGI) has not been previously reported. Recurrent DGI cases reported in the literature with identified cause are mostly associated with acquired or congenital complement pathway deficiencies. However, properdin deficiency is rarely screened for during a first episode. Our case not only highlights the clinical presentation that should raise suspicion of DGI but also underscores the importance of investigating the alternative complement pathway in such cases. At a time when gonococcal resistance is increasing, it is essential to consider existing strategies for preventing these infections, including vaccinations.

Rapid Diffusion of Awareness and Uptake of Doxy-PEP among Men who Have Sex with Men in San Francisco

In October 2022, the San Francisco Department of Public Health published guidelines for doxycycline post-exposure prophylaxis (doxy-PEP) to prevent bacterial sexually transmitted infections (STI) among men who have sex with men (MSM). We evaluated awareness and use of doxy-PEP using data from the National HIV Behavioral Surveillance in 2023 in San Francisco (N = 533). In the year following the publication of the guidelines, 66.6% of MSM reported awareness of doxy-PEP, and 19.3% had used it. Among MSM who are not living with HIV, awareness of doxy-PEP was associated with higher educational levels, condomless sex, bacterial STI diagnoses, and PrEP use; use was associated with STI diagnoses and PrEP use. Among MSM living with HIV, both awareness and use were associated with younger age. These findings indicate rapid dissemination and early adoption of doxy-PEP in a priority population in a real-world setting.

Preventing Premature Pre-Exposure Prophylaxis Discontinuation and Sexually Transmitted Infections Among Men Who Have Sex With Men (Project PEACH): Protocol for a Prospective Cohort Study

BACKGROUND

There is an ongoing syndemic of HIV and sexually transmitted infections (STIs) in the United States, particularly among men who have sex with men (MSM). We have increasingly effective and diverse measures of prevention, including various types of pre-exposure prophylaxis (PrEP) for HIV prevention and doxycycline postexposure prophylaxis (doxyPEP) for STI prevention. As options expand, we need to understand how to use a combination of these strategies and other supports for MSM to best curb the syndemic.

OBJECTIVE

We designed a patient-preference trial to understand patient preferences for PrEP and doxyPEP, how preferences may change over time, and methods for preventing premature discontinuation of PrEP.

METHODS

We enrolled HIV-negative MSM in metropolitan Atlanta, Georgia. Participants could elect to take PrEP (daily or on-demand), doxyPEP, both, or neither, along with app-based support to evaluate for risk factors of discontinuation or behavioral changes that might affect their choice of prevention methods. Participants were able to switch prevention methods at any time. Oral PrEP and doxyPEP users are currently being offered quarterly in-person or at-home HIV, syphilis, gonorrhea, and chlamydia testing along with opportunities for motivational interviewing.

RESULTS

We enrolled individuals from November 2021 to September 2023. Among 240 participants, the median age was 30 (IQR 25-35), 63% (n=150) self-identified as non-Hispanic Black, and 69% (n=166) were insured. Most participants (n=144, 60%) elected to take daily PrEP plus doxyPEP, with a smaller proportion taking on-demand PrEP plus doxyPEP (n=34, 14%) or daily PrEP without doxyPEP (n=33, 14%).

CONCLUSIONS

We designed an ongoing study to evaluate the preferences for PrEP and doxyPEP among MSM in metropolitan Atlanta. Enrollment was completed in 22 months and included a diverse cohort of MSM that will be followed longitudinally to evaluate prevention preferences over time. At baseline, most participants preferred to take a combination of daily PrEP and doxyPEP for HIV and STI prevention.

TRIAL REGISTRATION

Clinicaltrials.gov NCT05072093; https://clinicaltrials.gov/study/NCT05072093.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/56096.

Staphylococcus aureus Tetracycline Resistance and Co-resistance in a Doxycycline Postexposure Prophylaxis-Eligible Population

Among doxycycline postexposure prophylaxis (doxy-PEP)-eligible men, Staphylococcus aureus tetracycline nonsusceptibility is more prevalent than in the overall population and is associated with resistance to trimethoprim-sulfamethoxazole and clindamycin. Doxy-PEP may select for multidrug-resistant S aureus, underscoring the importance of surveillance.

Revisiting the potential impact of doxycycline post-exposure prophylaxis on the selection of doxycycline resistance in Neisseria commensals

Doxycycline post-exposure prophylaxis (doxy-PEP) is a strategy to reduce bacterial sexually transmitted infections. However, the impact of doxy-PEP on resistance emergence is as of yet unclear. Commensal Neisseria are known reservoirs of resistance for gonococci through horizontal gene transfer (HGT), and are more likely to experience bystander selection from doxy-PEP as they are universally carried. 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, collection of commensals from human hosts demonstrated 46% of isolates carry 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 the ribosomal protection protein (tetM) and pConj. In vitro selection of Neisseria commensals (N. cinerea, N. canis, N. elongata, and N. subflava) resulted in 12 of 16 lineages evolving doxycycline resistance (> 1 µg/mL). An A46T substitution in the repressor of the Mtr efflux pump (MtrR) and a V57M substitution in the 30 ribosomal protein S10 were associated with elevated MICs. Mutations in ribosomal components also emerged (i.e., 16 S rRNA G1057C, RplX A14T). We find the MtrR 46T, RpsJ 57M, and RplX 14T in natural commensal populations. 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. This work underscores the importance of commensal Neisseria as reservoirs of doxycycline resistance, and demonstrates a link between doxycycline use and the emergence of resistance. Though novel chromosomal resistance mutations are nominated herein, resistance emergence in natural commensal populations appears to be mainly associated with acquisition of the tetM gene. A secondary danger to pConj acquisition, is spread of pbla and β-lactam resistance, which we demonstrate here in vitro. 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 resistance across species' boundaries.

Impact of Targeted Outreach to Increase Linkage to Preventative Services for Patients Tested for Mpox

Early in the Mpox outbreak, individuals presenting for Mpox testing often did not receive comprehensive sexually transmitted infection (STI) screening upon presentation. This study aims to assess the impact of targeted outreach on linkage to STI and HIV screening and HIV pre-exposure prophylaxis (PrEP) counseling for individuals presenting for Mpox testing. Individuals who had tested for Mpox were contacted via an existing STI outreach team in Dallas, Texas, to engage in STI/HIV screening and other preventive services between June 2022 and March 2023. On retrospective chart review, 414 individuals were tested for Mpox with 203 PCR-confirmed cases. 238/414 (58%) were previously diagnosed with HIV. 76/176 (43%) of individuals with unknown HIV status were screened for HIV, and six new cases of HIV were identified. One-third (136/414) were also tested for other STIs (chlamydia, gonorrhea, or syphilis), with 45 new cases identified. 94/414 (23%) individuals were contacted for outreach after initial Mpox testing. Patients who received outreach were more likely to be tested for HIV (10/26 [38.4%]) compared with those who did not receive outreach (19/144 [13.3%]) (p < 0.001) and more likely to undergo additional STI testing (58/94 [62%] vs. 109/320 [34%]) (p < 0.001). More individuals in the outreach group were counseled on starting PrEP than in the non-outreach group (14/26 [53.8%] vs. 8/144 [5.6%]) (p = 0.0016). Targeted outreach increased screening for HIV and other STIs and counseling for PrEP among patients presenting for Mpox testing. Strategies to increase linkage to preventive services are needed to reduce coinfections of Mpox, HIV, and other STIs.

New Prevention Measures in Venereology: Evidence Review on the DoxiPrEP/PEP Antibiotic and the 4CMenB Vaccine

Sexually transmitted infections (STIs) are increasing in Spain. The traditional strategy for STI control is mainly based on screening and treatment of STIs in patients with risky sexual practices. In recent years, new interesting primary and secondary prevention strategies are being studied to reduce the incidence rate of STIs in high-risk populations. The most interesting one, based on the evidence obtained, is the use of doxycycline and meningococcal B vaccines. Specialists in dermatology and venereology must be informed about these new developments that may have an impact on the way in which STIs are managed worldwide. This is a scientific evidence review of these new interesting primary and secondary prevention strategies to control STIs in a high-risk population.

Assessing the Risk of Sexually Transmitted Infections among Men who have Sex with Men in San Francisco during COVID-19: A Socio-ecological Analysis

BACKGROUND

Men who have sex with men (MSM) are disproportionately affected by sexually transmitted infections, a disparity that has only worsened in recent years. During the COVID-19 pandemic, an overall increasing trend remained.

METHODS

We utilized data from the MSM cycle of the National HIV Behavioral Surveillance (NHBS) study in San Francisco, California, conducted from June 2021 through December 2021, to identify socio-ecological disruptions during the COVID-19 pandemic that were associated with sexually transmitted infections.

RESULTS

In total, 505 participants were surveyed, and approximately 24% of the participants reported having been diagnosed with an STI infection within the past 12 months. In the adjusted Poisson regression models, socio-ecologic factors that were independently associated with STI infection included barriers to STI testing due to COVID-19 (aRR 1.62, 95% CI 1.18-2.23), sex with partners part of small social circles/pods (aRR 2.41, 95% CI 1.41-4.12), sex with partners whose risk for COVID-19 was not known (aRR 3.53, 95% CI 2.05-6.06), and an increase or relapse in recreational substance use (aRR 2.01, 95% CI 1.49-2.72).

CONCLUSIONS

These findings indicate the importance of enacting comprehensive policies that not only address an ongoing global pandemic but also consider its potential effects on other public health epidemics, such as sexually transmitted infections among men who have sex with men.

A Qualitative Study of Doxycycline Postexposure Prophylaxis Knowledge, Attitudes, and Practices Among Health Care Providers in New York City

BACKGROUND

Three randomized controlled trials have demonstrated the efficacy of doxycycline for bacterial sexually transmitted infection postexposure prophylaxis (Doxy PEP). Few studies have assessed provider knowledge, attitudes, and practices (KAP) regarding Doxy PEP implementation. Between July of 2023 and January 2024, this study qualitatively assessed KAP and intention to prescribe Doxy PEP among health care providers in the New York City area.

METHODS

In-depth, semistructured individual interviews were conducted with 18 health care provider key informants including physicians, nurse practitioners, and physician assistants from various practice settings. Transcripts were analyzed using inductive KAP codes, with additional deductive coding used to identify emergent subthemes.

RESULTS

The following themes were identified: (1) STI Disparities, (2) Doxy PEP Experience, (3) Doxy PEP Benefits, (4) Doxy PEP Concerns, and (5) Doxy PEP Implementation. Doxy PEP knowledge was high, with all providers being aware and most (78%) having prescribed it to at least one patient at the time of interview. Providers were knowledgeable of factors contributing to high rates of STIs. Benefits included reducing STI anxiety. Concerns included contributing to antimicrobial resistance and impacts on microbiota. Practice implications included challenges getting Doxy PEP approved by the pharmacy. These factors were shown to affect Doxy PEP's perceived acceptability.

CONCLUSIONS

To ensure that Doxy PEP is implemented safely and equitably, KAP factors that may influence provider decision making should be examined. Understanding providers' KAP and how they affect intention to prescribe Doxy PEP, and to what patients, has important implications for successful implementation.

Antimicrobial susceptibility of commensal Neisseria species in the Japanese population

OBJECTIVES

We aimed to, for the first time, characterize the antimicrobial susceptibilities of commensal Neisseria species in the general population in Japan. In particular, we assessed if the tetracycline minimum inhibitory concentrations (MICs) of these isolates were changing over time and, given the recent interest in doxycycline post exposure prophylaxis (PEP), if the tetracycline MICs were associated with those of the other antimicrobials.

METHODS

Neisseria spp. were isolated from 1679 patients visiting dental clinics in Japan between 2018 and 2023. The MICs of tetracycline, ceftriaxone, cefixime, penicillin, azithromycin and ciprofloxacin against Neisseria spp. were determined using agar dilution. Linear regression was used to assess if there was an association between MIC and the year the isolate was obtained from, controlling for species identity.

RESULTS

Neisseria spp. were detected in 424 of 1679 individuals sampled. Of these, 417 (98.3 %) isolates were identified as Neisseria subflava, and the remaining 7 (1.7 %) as Neisseria mucosa. The median tetracycline MIC was 0.5 mg/L (IQR 0.5-1 mg/L). The MICs of penicillin, cefixime, ceftriaxone and ciprofloxacin were lower in N. mucosa than in N. subflava. The tetracycline MICs of Neisseria spp. were positively correlated with penicillin, azithromycin and ciprofloxacin. No significant correlations were found with cefixime or ceftriaxone.

CONCLUSIONS

Our results suggest that despite the overall decline in antimicrobial use in Japan, MICs for several antimicrobials have increased over time. In particular, the MIC of tetracycline tends to be high in Japan. These results suggest the need to include surveillance of tetracycline MICs of commensal Neisseria spp. in doxycycline PEP implementation studies.

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 exerts bactericidal activity against Gc and, unlike other Gram-negative bacteria, disrupts both the outer and inner membranes. C5b-C8 complex formation potentiates Gc sensitivity to azithromycin and ceftriaxone, but not lysozyme or nisin. 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 that 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, 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 that 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 and nisin, but azithromycin and ceftriaxone 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.

Doxycycline to prevent bacterial sexually transmitted infections in the USA: final results from the DoxyPEP multicentre, open-label, randomised controlled trial and open-label extension

BACKGROUND

Doxycycline post-exposure prophylaxis (doxy-PEP) is a promising intervention to reduce bacterial sexually transmitted infections (STIs). We evaluated the effect of doxy-PEP on STI incidence and antimicrobial resistance in men who have sex with men and transgender women for up to 12 months of follow-up, inlcuding an open-label extension.

METHODS

DoxyPEP, an open-label trial in Seattle (WA, USA) and San Francisco (CA, USA) among men who have sex with men and transgender women with at least one bacterial STI in the past year, randomly assigned participants by clinic (with computer-generated variable block sizes) 2:1 to doxy-PEP (200 mg doxycycline delayed-release tablets 24-72 h after condomless sex) or standard care. The independent endpoint adjudication committee was masked to group assignment. The primary outcome was presence of one or more bacterial STIs (Neisseria gonorrhoeae, Chlamydia trachomatis, or early syphilis) each quarter. This outcome was assessed in the modified intention-to-treat cohort, which included participants with at least one follow-up quarter (ie, ∼3 months) in their as-randomised assignment. After early termination of the randomised phase for efficacy, all participants still enrolled were offered doxy-PEP in an open-label extension (OLE). We report quarterly incidence of bacterial STIs for the as-randomised and OLE periods. Safety was assessed in all participants with any follow-up data. The trial was registered with ClinicalTrials.gov (NCT03980223) and is completed.

FINDINGS

From Aug 19, 2020, to May 13, 2022, we enrolled 637 participants; 592 participants completed at least one follow-up quarter in the randomised phase (411 in the doxy-PEP group and 181 in the standard-care group) and 282 in the OLE phase (207 in the doxy-PEP group and 82 in the standard-care group). STIs were present in 129 (12·0%) of 1077 quarters in the doxy-PEP group versus 139 (30·5%) of 455 quarters in the standard-care group during the as-randomised period, showing an absolute difference of 19 percentage points and a relative risk of 0·39 (95% CI 0·31-0·49, p<0·0001). During the OLE, STIs were diagnosed in 51 (13%) of 388 quarters among those continuing doxy-PEP and 25 (17%) of 145 quarters among standard-care participants who initiated doxy-PEP. Throughout all quarters for participants on doxy-PEP, there was one grade 2 laboratory abnormality and five grade 3 adverse events that were possibly or probably related to doxy-PEP. No serious adverse events were attributed by site investigators to doxycycline. Of participants with positive gonorrhoea cultures during the study, eight (27%) of 29 taking doxy-PEP versus five (24%) of 21 not taking doxy-PEP had tetracycline resistance (minimum inhibitory concentration ≥2 μg/mL).

INTERPRETATION

Doxy-PEP was effective in reducing bacterial STIs in this population of men who have sex with men and transgender women, including during an open-label extension when doxy-PEP efficacy was known. Doxy-PEP was well tolerated, highly acceptable, and with no new safety signals.

FUNDING

US National Institutes of Health.

In Vitro Exposure of Treponema pallidum to Subbactericidal Doxycycline Did Not Induce Resistance: Implications for Doxycycline Postexposure Prophylaxis

Doxycycline postexposure prophylaxis (doxy-PEP) could significantly reduce syphilis incidence. However, the increase in intermittent doxycycline usage might select resistant Treponema pallidum strains. To assess whether resistance to doxycycline could be induced in this pathogen, we exposed the SS14 strain in vitro, both intermittently and continuously, to a subbactericidal doxycycline concentration that still exerts antibiotic pressure. During and after each exposure experiment, we assessed the doxycycline minimal inhibitory concentration in test and control treponemes and performed whole-genome sequencing, concluding that no resistance developed. This work suggests that doxycycline-resistant T. pallidum is not an immediate threat for doxy-PEP implementation.

Factors associated with placement along the HIV prevention and care continuum among sexual minority men who use methamphetamine

Methamphetamine use among sexual minority men (SMM) has been associated with poor ART adherence, and reduced initiation and adherence to PrEP. From May 2021 to May 2023, 226 SMM were enrolled in Getting Off, a culturally responsive smartphone application to reduce methamphetamine use and improve sexual health. Using a status-neutral approach, an ordinal variable reflected participants' placement on the HIV Prevention/Care Continuum, from HIV-positive, not taking ART, to HIV-negative, currently taking PrEP. An ordinal logistic model was structured to identify factors associated with participants' placement on the Continua. Of the 99 SMM at risk of HIV, 57.6% had an HIV test within three months. The majority (n = 77; 77.8%) had heard of PrEP, among whom only 28 (36.4%) were currently on PrEP. Among the 127 (56.2%) participants with HIV, 61 (48.0%) had viral load testing in the last three months, and 48 (37.8%) were virally suppressed. With demographics, social determinants of health, and substance use/sexual risk behaviors controlled, those with post-graduate education were more likely to have higher placement in the Continua (OR = 2.12, P = 0.011). STI in the past 12 months was correlated with lesser placement (OR = 0.57; P = 0.045). Neither methamphetamine use disorder nor readiness to change was correlated with Continua placement.

Doxycycline Postexposure Prophylaxis and Sexually Transmitted Infection Trends

Importance

Increasing rates of sexually transmitted infections (STIs) have been associated with rises in serious morbidity. While doxycycline postexposure prophylaxis (doxyPEP), a strategy in which individuals take doxycycline, 200 mg, after condomless sex to prevent bacterial STIs, has been shown to be efficacious in randomized clinical trials, doxyPEP's potential effect on population-level STI incidence is unknown.

Objective

To assess the association of citywide doxyPEP guideline release with reported chlamydia, gonorrhea, and early syphilis cases in men who have sex with men (MSM) and in transgender women in San Francisco, California.

Design, Setting, and Participants

This population-level interrupted time series analysis of reported San Francisco STI cases measured monthly cases of chlamydia, gonorrhea, and early syphilis prior to (July 2021-October 2022) and after (November 2022-November 2023) release of citywide doxyPEP guidelines in October 2022. All reported chlamydia, gonorrhea, and early syphilis cases among MSM and transgender women in San Francisco during the period of analysis were included. Data were analyzed November 2023 to July 2024.

Exposure

Release of doxyPEP citywide guidelines.

Main Outcomes and Measures

The primary outcome was the percentage change between projected and observed chlamydia, gonorrhea, and early syphilis cases in the 13-month postexposure period.

Results

Citywide, there were 6694 cases of chlamydia, 9603 cases of gonorrhea, and 2121 cases of early syphilis among MSM and transgender women during the analytic period. STI cases among MSM and transgender women decreased significantly compared with model projections for chlamydia (-6.58% per month; 95% CI, -7.99% to -5.16%) and early syphilis (-2.68% per month; 95% CI, -3.75% to -1.60%) after doxyPEP implementation. By the end of the 13-month postperiod in November 2023, chlamydia and early syphilis cases decreased -49.64% (95% CI, -59.05% to -38.06%) and -51.39% (95% CI, -58.21% to -43.46%), respectively, compared with projected cases. There was a significant increase in monthly gonorrhea cases compared with projections (1.77% per month; 95% CI, 0.87% to 2.67%).

Conclusions and Relevance

This study suggests that San Francisco's doxyPEP guideline release was associated with decreases in reported cases of chlamydia and early syphilis, but not gonorrhea, among MSM and transgender women in San Francisco. Further analyses are needed to assess whether declines are sustained and monitor for adverse consequences, including antimicrobial resistance. Supporting doxyPEP implementation for MSM and transgender women at risk for STIs could have a significant impact on the nationwide STI epidemic.

DOXY do, or DOXY Don't? Syphilis and doxycycline post-exposure prophylaxis: A case report

The resurgence of syphilis across Europe has led to a growing number of atypical cases, often characterised by varied symptoms that can delay diagnosis. We report the case of a young man who has sex with men (MSM), presenting with persistent headaches and swelling of the forehead suggestive of giant cell arteritis (GCA). Despite a recent negative syphilis test, further investigations confirmed the diagnosis of neurosyphilis. The patient had been using doxycycline post-exposure prophylaxis (DoxyPEP), which is suspected to have delayed the diagnosis by masking the typical antibody response. This case highlights concerns about DoxyPEP's impact on syphilis detection and disease progression. Further research is warranted to explore its effects on antimicrobial resistance, the human microbiome, and clinical outcomes.

Doxycycline post-exposure prophylaxis for preventing bacterial sexually transmitted infections (STIs): Are clinical providers supportive?

BACKGROUND

Bacterial sexually transmitted infections (STIs) continue to increase in the United States. Despite evidence of the effectiveness of doxycycline post-exposure prophylaxis (Doxy-PEP) to prevent STIs, little is known about providers' attitudes and willingness to implement Doxy-PEP.

METHODS

An online questionnaire was sent to 575 clinical providers in New York State in September 2022.

RESULTS

Ninety-one eligible individuals responded. Most providers served men who have sex with men (MSM) (84%); reported willingness to recommend Doxy-PEP (98%, 77%, and 67% for chlamydia, syphilis, and gonorrhea, respectively); preferred Doxy-PEP administration for MSM and transgender populations; believed recurring bacterial STIs (88%) and reported condomless sex (85%) were the most important characteristics to consider for recommending Doxy-PEP; and were concerned about antibiotic resistance (90%) (primarily for Neisseria gonorrhoeae). Insurance costs were the most perceived community-associated barriers (35%). There were no significant differences in providers' recommendations towards Doxy-PEP use when comparing clinicians' years of experience, regions, or professional titles.

CONCLUSIONS

Study results suggest high willingness and support for implementing Doxy-PEP. As this survey was administered prior to national guidelines on the use of Doxy-PEP, these data can be used as a baseline to compare to studies conducted after their release to formulate appropriate messages for providers to improve implementation.

Another Tool for the Sexual Health Toolkit: US Health Care Provider Knowledge and Attitudes About Doxycycline Postexposure Prophylaxis to Prevent Bacterial Sexually Transmitted Infections Among Men Who Have Sex With Men

BACKGROUND

Doxycycline post-exposure prophylaxis (doxy-PEP) reduces chlamydia, gonorrhea, and syphilis infections among men who have sex with men (MSM) and transwomen (TW). Perspectives of health care providers (HCPs) regarding doxy-PEP can inform implementation efforts.

METHODS

From August 2022 to January 2023, HCPs were recruited from 13 cities with high sexually transmitted infection (STI) rates for semi-structured, in-depth interviews about their awareness of and attitudes toward doxy-PEP for STI prevention. Health care providers were purposively sampled to include people with experience prescribing PrEP and provision of care to MSM. Interviews were conducted virtually via Zoom. Transcripts and debrief reports were analyzed using a directed content analysis approach to explore knowledge, attitudes, and beliefs about doxy-PEP.

RESULTS

Among 30 HCPs, almost half (47%) were between 31-40 years of age, 53% identified as male, and 47% reported their sexual orientation as gay or queer. Half (53%) of participants practiced in the South, 43% had >100 MSM in their clinic panel, and 17% had previously prescribed doxy-PEP. We identified four overarching themes: 1) HCPs expressed positive attitudes toward doxy-PEP; 2) antimicrobial resistance concerns limit enthusiasm for some HCPs; 3) additional data about the long-term safety of doxy-PEP would improve their confidence; and 4) development of guidelines would facilitate the prescription of doxy-PEP, including eligibility, dosing instructions, and treatment management.

CONCLUSION

HCPs were motivated to prescribe doxy-PEP with almost 20% already having prescribed it. Guidelines and data about long-term safety, especially antimicrobial resistance, would facilitate introduction of doxy-PEP into clinical practice.

Doxycycline Postexposure Prophylaxis and Bacterial Sexually Transmitted Infections Among Individuals Using HIV Preexposure Prophylaxis

Importance

Doxycycline postexposure prophylaxis (doxyPEP) has been shown to decrease the incidence of bacterial sexually transmitted infections (STIs) among people assigned male sex at birth in clinical trials, but data from clinical practice are limited.

Objective

To describe early uptake of doxyPEP and evaluate changes in STI incidence following doxyPEP initiation.

Design, Setting, and Participants

This retrospective cohort study of adults (aged ≥18 years) dispensed HIV preexposure prophylaxis (PrEP) at Kaiser Permanente Northern California during November 1, 2022, to December 31, 2023, examined electronic health record data to compare HIV PrEP users dispensed and not dispensed doxyPEP and rates of bacterial STIs before and after starting doxyPEP. Individuals were followed up from their first recorded STI test on or after November 1, 2020, until December 31, 2023, or discontinuation of health plan membership.

Exposure

Pharmacy dispensing data were used to define doxyPEP recipients.

Main Outcomes and Measures

Demographic and clinical characteristics were compared between individuals dispensed and not dispensed doxyPEP. Primary outcomes were incident chlamydia, gonorrhea, or infectious syphilis measured as quarterly STI positivity (proportion of individuals testing positive at least once per quarter). Among doxyPEP recipients, rate ratios (RRs) compared mean quarterly STI positivity from 24 months before to 12 months after starting doxyPEP. In an exploratory analysis, STI trends were evaluated for the full cohort, stratified by receipt of doxyPEP.

Results

Among 11 551 HIV PrEP users (mean [SD] age, 39.9 [12.1] years; 95.1% male), 2253 (19.5%) were dispensed doxyPEP, of whom 2228 (98.9%) were male and 1096 (48.6%) had an STI in the year before starting doxyPEP. Compared with individuals not dispensed doxyPEP, doxyPEP recipients were older (mean [SD] age, 40.4 [10.8] vs 39.8 [12.4] years; P = .04) and had used HIV PrEP longer (mean [SD], 4.2 [2.8] vs 3.4 [2.6] years; P < .001), and a higher proportion were commercially insured (2091 [92.8%] vs 8270 [88.9%]; P < .001). Among doxyPEP recipients, quarterly chlamydia positivity decreased from 9.6% (95% CI, 9.0%-10.3%) before starting doxyPEP to 2.0% (95% CI, 1.5%-2.6%) after starting doxyPEP (RR, 0.21; 95% CI, 0.16-0.27; P < .001), with significant declines for each anatomic site of infection. Quarterly gonorrhea positivity decreased from 10.2% (95% CI, 9.6%-10.9%) before starting doxyPEP to 9.0% (95% CI, 8.0%-10.1%) after starting doxyPEP (RR, 0.88; 95% CI, 0.77-1.00; P = .048); site-specific declines were significant for rectal (RR, 0.81; 95% CI, 0.67-0.97; P = .02) and urethral (RR, 0.56; 95% CI, 0.40-0.79; P = .001) gonorrhea, but not pharyngeal gonorrhea. Quarterly syphilis positivity decreased from 1.7% (95% CI, 1.4%-1.9%) before starting doxyPEP to 0.3% (95% CI, 0.2%-0.6%) after starting doxyPEP (RR, 0.20; 95% CI, 0.11-0.37; P < .001). Positivity for STIs remained stable in individuals not dispensed doxyPEP.

Conclusions and Relevance

This study found that receipt of doxyPEP was associated with substantial declines in chlamydia and syphilis incidence and modest declines in urethral and rectal gonorrhea incidence among individuals using HIV PrEP. These findings suggest that doxyPEP may offer substantial benefits for reducing population-level STI transmission with broader implementation.

DoxyPEP Implementation Preferences for Bacterial STD Prevention Among Gay, Bisexual, and Other Men Who Have Sex with Men Living With and Without HIV in Los Angeles: A Mixed-Methods Approach

Bacterial sexually transmitted diseases (STDs) remain prominent in the United States among gay, bisexual, and other men who have sex with men (GBMSM). Doxycycline for post-exposure prophylaxis (DoxyPEP) is a regimen by which the antibiotic doxycycline is taken after sex to prevent bacterial STDs, such as, chlamydia, gonorrhea, and syphilis. Despite this, this study was conducted because there are a limited number of publications that describe GBMSM's knowledge of, and interest in, taking DoxyPEP and preferences regarding its implementation. We conducted a mixed-methods study between November 2023 and March 2024. Participants (N = 21) completed a semi-structured interview and survey and were eligible if they were a cisgender man who reported having anal sex with another man in the past year and lived in the greater Los Angeles area. Interviews were recorded and transcribed and were analyzed using thematic content analysis. The majority of participants identified as gay (90%) and a racial/ethnic minority (86%); 33% were living with HIV and 43% had been diagnosed with an STD in the prior year. Participants' mean age was 40 years (standard deviation [SD] = 15) and they reported an average of 4.5 (SD = 2.27) sexual partners in the past year. Interviews revealed that knowledge of DoxyPEP was low (28%), but most (81%) were interested in using DoxyPEP after learning about its potential. The vast majority were willing to pay $10-$20 for a 1-month supply but preferred that it be free or covered by insurance. Most preferred to get DoxyPEP from a medical provider or over-the-counter at a pharmacy. Others suggested sexualized venues, such as private sex parties, bathhouses, sex clubs, etc. The greatest concerns about its use included possible side effects, antibiotic resistance, or that it would lead to decreased condom use and increased number of sex partners. A common misconception was that DoxyPEP could prevent both a bacterial STD and HIV. DoxyPEP has strong potential as a widely accepted STD prevention method, but its successful adoption will require proactive strategies to increase GBMSM's knowledge. Implementation programs might consider nontraditional venues where sex between men is regularly occurring.

The Association Between Syphilis Infection and HIV Acquisition and HIV Disease Progression in Sub-Saharan Africa

Syphilis and other sexually transmitted infections (STIs) are highly prevalent in most regions experiencing severe human immunodeficiency virus (HIV) epidemics. In sub-Saharan Africa, the region most heavily affected by HIV, the prevalence of syphilis among people living with HIV (PLWH) is notably high. This region accounts for 40% of global STIs and 70% of HIV cases. Despite the high prevalence of syphilis and other STIs among PLWH in the region, there are limited studies on the interplay between the two infections from the region. Most studies on the association between syphilis and HIV transmission/progression from the region are limited to specific groups of people, such as female sex workers or pregnant women. In this manuscript, we evaluated the association between the two infections using population-based surveys conducted in the region. Statistical methods (such as logistic regression models and propensity score matching) were employed to assess the interplay between the two infections. Our findings indicated that syphilis infection was associated with higher odds of HIV acquisition. Moreover, co-infection with syphilis was associated with higher odds of HIV disease progression among antiretroviral therapy (ART)-treated PLWH, though the association did not reach statistical significance. Our findings suggest that the recognition and treatment of syphilis to reduce the risk of HIV acquisition/progression should be a public health priority in sub-Saharan Africa, where ART may not be readily available.

State-of-the-Art Review: Data and Trust to Improve Care for Transgender and Gender-Diverse Patients

Healthcare for transgender and gender-diverse (TGD) patients is evolving. With 1.6 million people in the United States identifying as transgender, clinicians have significant opportunity to learn, build trust, and offer thoughtful preventive and therapeutic care. Gender-affirming care starts by using chosen names and pronouns and creating welcoming environments. Medical and surgical care for TGD persons is endorsed by multiple medical societies and is associated with reduced symptoms of dysphoria and improved quality of life. Barriers accessing this care include a lack of provider knowledge and availability, socioeconomic factors, discrimination, ongoing anti-LGBTQ+ legislation, and mistreatment from the medical system. Complications of gender-affirming surgical procedures are uncommon when performed by qualified and well-trained surgeons, though often patients must travel significant distances to attain surgical care, limiting postoperative follow-up. Complications of non-medical-grade procedures, such as fillers, are common and can present many years after the initial procedure. With respect to sexual wellness, social and biomedical interventions addressing disproportionate effects of human immunodeficiency virus and sexually transmitted infections on TGD people show promise in clinical trials. Further education for providers and patients, advocacy for affirming spaces and policies promoting evidence-based care, and building trust are crucial for holistic care of TGD patients.

Promises, Pitfalls, and Progress: Doxycycline Prophylaxis for Bacterial Sexually Transmitted Infections

PURPOSE OF REVIEW

Doxycycline post-exposure prophylaxis (doxy PEP) has proven to be highly effective in reducing the incidence of sexually transmitted infections (STIs) among men who have sex with men (MSM) and transgender women. In response, the US Centers for Disease Control and Prevention (CDC) issued official clinical guidance on the use of doxy PEP as a preventive intervention in these populations. However, despite strong evidence supporting its use, the potential risks of antimicrobial resistance (AMR) along with its limited accessibility in other key populations, remain significant concerns with doxy PEP.

RECENT FINDINGS

Real-world data show strong awareness, interest, and usage of doxy PEP among MSM and transwomen. Early ecological studies have revealed population-level reductions in chlamydia and early syphilis incidence following doxy PEP implementation. Ongoing research continues to explore its efficacy in other populations, as well as its impact on both individual and population-level AMR. Doxy PEP is a well-tolerated and inexpensive intervention that has the potential to substantially reduce bacterial STIs, particularly in priority populations. Its implementation will require careful assessment of equitable uptake, usage patterns, and long-term monitoring of STI incidence and AMR.

Antiretroviral Drugs for Treatment and Prevention of HIV in Adults: 2024 Recommendations of the International Antiviral Society-USA Panel

Importance

New data and new antiretroviral drugs and formulations continue to become available for the prevention and management of HIV infection.

Objective

To provide updated recommendations for HIV treatment and clinical management and HIV prevention.

Methods

A panel of volunteer expert physician scientists were appointed to provide updated consensus recommendations for 2024. Relevant evidence in the literature since the last report was identified from PubMed and Embase searches (which initially yielded 3998 unique citations, of which 249 were considered relevant); from ongoing monitoring of the literature by the panel members; from data submitted by product manufacturers; and from studies presented at peer-reviewed scientific conferences between June 2022 and October 2024.

Findings

Antiretroviral therapy continues to be recommended for all individuals with HIV. For most people with HIV, initial regimens composed of an integrase strand transfer inhibitor (InSTI), specifically bictegravir or dolutegravir, with 2 (and in some cases 1) nucleoside or nucleotide reverse transcriptase inhibitors are recommended. Recommendations are made for those with particular clinical circumstances, such as pregnancy and active opportunistic diseases, as well as for those unable to take InSTIs. Regimens may need to be changed for virologic failure, adverse effects, convenience, or cost, among other reasons. Long-acting injectable therapy is available for those who prefer not to take daily oral medications and for people struggling with adherence to daily therapy. Recommendations are provided for laboratory monitoring, management of substance use disorders and weight changes, as well as use of statins for cardiovascular disease prevention. For HIV prevention, oral (daily or intermittent) and injectable long-acting medications are effective options for people at increased likelihood of HIV exposure. Further, new tools for maintaining health and well-being among people with HIV, such as doxycycline postexposure prophylaxis to avert sexually transmitted infection, and strategies to treat substance use disorders, are recommended. Disparities in HIV acquisition and care access are discussed and solutions proposed.

Conclusions

New approaches for treating and preventing HIV offer additional tools to help end the HIV epidemic, but achieving this goal depends on addressing disparities and inequities in access to care.

["How to get your Doxy-PEP?": vulnerabilities and critical routes encountered by men in the therapeutic itinerary in Brazil]

This study aimed to investigate the context of doxycycline-based post-exposure prophylaxis (Doxy-PEP) use for the prevention of sexually transmitted infections (STIs) by men who have sex with men (MSM) in Brazil. A qualitative study was conducted with 32 MSM participants, selected on social media. Data was collected by online questionnaires, which included open-ended questions about experiences with Doxy-PEP, access to medications, and interactions with the health care system. Responses were analyzed using the IRaMuTeQ program for descending hierarchical classification and reflective thematic analysis. The results revealed three main categories: (1) access to and management of post-exposure prophylaxis, in which participants reported difficulties in obtaining Doxy-PEP due to prescribing restrictions and lack of information; (2) perceptions and knowledge on risks and prevention, which highlighted a mix of knowledge and misinformation about STIs and prevention strategies; (3) social and behavioral dynamics, demonstrating how social interactions and stigma influence prevention practices. The study also indicated self-medication and drug storage as common practices. The study identified multiple barriers to access and management of Doxy-PEP among MSM in Brazil, influenced by individual, social, and programmatic factors. It is imperative to develop public health strategies that improve access to and information about Doxy-PEP among MSM, as well as approaches that reduce STIs-associated stigma.

Doxycycline prophylaxis for bacterial 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 bacterial 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 bacterial STI prevention among men who have sex with men (MSM) using HIV pre-exposure prophylaxis (HIV-PrEP) in Vietnam.

METHODS

Between 25 January and 4 February 2024, a cross-sectional study recruited males aged ≥18 years who reported having sex with men in the past 12 months from 11 HIV-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 doxycycline prophylaxis.

RESULTS

Among 350 participants, the median age was 25 (IQR 21-30), and 10.6% self-reported a bacterial 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 OR (aOR) 4.17; 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 doxycycline prophylaxis among MSM on HIV-PrEP in Vietnam was low. However, most expressed willingness to use it, with two-thirds preferring doxyPrEP. Findings highlight the need to disseminate information on doxycycline prophylaxis for bacterial STI prevention, monitoring the usage and evaluating comparative effectiveness of doxyPEP and doxyPrEP to guide implementation efforts in Vietnam.

Significant Publications on Infectious Diseases Pharmacotherapy in 2023

Purpose: To provide a summarization of the most significant infectious diseases (ID) pharmacotherapy articles published in peer-reviewed literature in 2023. Summary: Members of the Houston Infectious Diseases Network (HIDN) nominated notable articles providing significant contributions to ID pharmacotherapy in 2023. Article nominations included those pertaining to general ID and human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) pharmacotherapy. Out of the 31 articles nominated by HIDN members, 22 pertained to general ID pharmacotherapy, and 9 pertained to HIV/AIDS pharmacotherapy. To aid selection of the most notable articles of 2023, a survey was created and distributed to members of the Society of Infectious Diseases Pharmacists (SIDP). Of the 153 SIDP members who participated in the survey, there were 118 recorded votes for the top 10 general ID pharmacotherapy articles and 55 votes were recorded for the top HIV/AIDS article. The most notable publications are summarized. Conclusion: Advances in antimicrobial stewardship and infectious disease states continue to occur. Sustained growth in the publication of ID-related articles over the past year contributed to this review's aim to aid clinicians in remaining current on potentially practice-changing ID pharmacotherapy publications from 2023. This review provides a summary of recently published ID literature, including emphasis on antimicrobial stewardship, appropriate treatment durations, new antimicrobials, and drug-resistant organisms.

High Incidence and Duration of Antibiotic Use Among a Cohort of Men Who Have Sex With Men in Seattle, Washington

Background

Doxycycline postexposure prophylaxis (doxy-PEP) effectively prevents bacterial sexually transmitted infections (STIs) but may increase antibiotic pressure. Little is known about longitudinal antibiotic use among men who have sex with men (MSM), a key population for doxy-PEP.

Methods

We analyzed data from a prospective cohort of MSM in Seattle, Washington, from 2016 to 2018, prior to the introduction of doxy-PEP. Antibiotic use and reason for prescription were self-reported in weekly surveys and extracted from medical records. We characterized antibiotic use across 49 weeks of follow-up, stratified by specific antibiotics of interest and reasons for prescription. Incidence rates (IRs) were calculated for the number of incident events of antibiotic initiation per 100 person-years (PY) at risk. We assessed factors associated with antibiotic initiation using negative binomial regression to estimate adjusted incidence rate ratios (IRRs).

Results

Among 140 participants, 68.6% (n = 96) received at least 1 antibiotic during follow-up, resulting in an overall IR of 264.5 events of antibiotic initiation per 100 PY and 1696 total days of antibiotic use. STI treatment was the most common reason for antibiotic initiation (IR, 153.5 events per 100 PY; 462 days); however, treatment for other conditions contributed most to overall days of antibiotic use (IR, 42.6 events per 100 PY; 947 days). An age of 25-39 years (IRR, 1.54 [95% confidence interval {CI}, 1.02-2.32]) and a history of bacterial STIs <12 months prior to enrollment (IRR, 1.81 [95% CI, 1.12-2.93]) were significantly associated with higher incidence of antibiotic initiation.

Conclusions

Antibiotic consumption among this population was very high. Our analysis provides a necessary foundation for assessing the potential impacts of doxy-PEP.

Efficacy of Doxycycline as Preexposure and/or Postexposure Prophylaxis to Prevent Sexually Transmitted Diseases: A Systematic Review and Meta-Analysis

INTRODUCTION

Bacterial sexually transmitted infections (STIs), specifically infection by Chlamydia trachomatis , Neisseria gonorrhoeae , and Treponema pallidum , have an important burden worldwide. The use of doxycycline as preexposure prophylaxis (PREP or doxy-PREP) or postexposure prophylaxis (PEP or doxy-PEP) might be effective as prophylaxis because it is effective against C. trachomatis and T. pallidum .

AIMS

Our objective was to evaluate the efficacy of doxycycline as PREP or PEP against bacterial STIs ( C. trachomatis , N. gonorrhoeae , and T. pallidum ).

METHODS

A systematic review and meta-analysis of randomized clinical trials of a high-risk group of individuals was conducted to evaluate whether doxycycline is as effective as PREP or PEP in preventing bacterial STIs. The PubMed-MEDLINE (MEDlars online), Cohrane, Scientific Electronic Library Online (SciELO), and Latin America and the Caribbean Literature on Health Sciences ( Literatura Latino-Americana e do Caribe em Ciências da Saúde -LILACS) databases were searched for randomized clinical trials published up to March 2024. Data were extracted from published reports. Hazard ratios (HRs) and risk ratios (RRs) with 95% confidence interval (CI) were pooled across trials.

MAIN OUTCOME MEASURE

The primary end points were any incidence of bacterial STIs and individual STI infections.

RESULTS

A total of 4 studies were included in the analysis, 3 of which evaluated doxy-PEP and 1 evaluated doxy-PREP. In the doxy-PEP group, a total of 1182 participants were evaluated. In the pooled analysis of doxy-PEP studies, the incidence of the first STI was lower in the doxy-PEP group (HR, 0.538 [95% CI, 0.337-0.859]; I2 = 77%; P < 0.05). Regarding individual infections, only 2 studies were included. In the doxy-PEP group, the incidence of individual infection of C. trachomatis was lower compared with controls (RR, 0.291 [95% CI, 0.093-0.911]) ( I2 = 89%; P < 0.05). Because only one study evaluated doxy-PREP, it was not possible to calculate a meta-analysis index; however, the use of doxycycline as PREP was associated with a decrease in the rate of any STI.

CONCLUSIONS

The use of doxy-PEP might reduce the first STI, mainly C. trachomatis , if used within 72 hours after condomless sex. The use of doxy-PREP might also decrease the chance of any STI; however, only 1 study was evaluated.

A practice already in use: a snapshot survey on the use of doxycycline as a preventive strategy (Doxy-PEP and Doxy-PrEP) in the GBMSM population in Spain

PURPOSE

. While doxycycline shows promise as a preventative measure against certain STIs (post-exposure prophylaxis or PEP, and pre-exposure prophylaxis or PrEP), very few medical and scientific associations favor its community use. Nevertheless, sexual health organizations for gay, bisexual and other men who have sex with men (GBMSM) community have noticed an increase in requests of its use.

METHODS

. The sexual health organization "Stop Sida" in Spain launched an anonymous snapshot survey to evaluate the current use of doxycycline as prevention strategy (both PEP and PrEP) in Spain through its social networks and its support groups in telegram.

RESULTS

. 150 valid answers were obtained from different parts of Spain. 82 respondents (54,6% of total) had ever taken doxycycline, out of which 29 (35,4%) indicated the use as doxy-PEP and 7 (8,5%) as doxy-PrEP. The self-reported rate of STI diagnoses (mainly of syphilis and chlamydia) in the past 12 months was lower among those participants who reported having used doxy-PEP compared with those who did not report using doxy-PEP. The most common ways to obtain the doxycycline were telling a specialist that they have had a risky contact or by using leftover pills from a previous treatment.

CONCLUSION

The current study is the first study to describe the use of doxycycline as a preventive strategy among the GBMSM community in Spain, and the first designed, launched and analyzed entirely by an NGO dealing with sexual health for the GBMSM community. The results obtained are aligned with other studies in other parts of Europe, such as Germany.

Disseminated Gonococcal Infection Presenting as an Isolated Rash in a Young Patient: A Case Report and Review of Atypical Presentations

Neisseria gonorrhoeae (N. gonorrhoeae)is a Gram-negative diplococcus responsible for sexually transmitted infections (STIs) worldwide. While gonorrhea primarily affects mucosal surfaces, disseminated gonococcal infection (DGI) can occur, presenting with polyarthritis, tenosynovitis, and dermatitis. However, atypical presentations can delay diagnosis and treatment. Men who have sex with men (MSM) are commonly affected by gonorrhea, necessitating vigilance for DGI in this population. A 24-year-old MSM with a history of previously treated gonorrhea presented with a petechial rash on the lower extremities and mild, painless foot swelling without systemic symptoms or joint involvement. The patient had engaged in multiple unprotected sexual encounters in the preceding month. Physical examination revealed a non-itchy, non-blanching rash, most prominent on the dorsum of the feet and sparing the soles. Laboratory findings showed leukocytosis and pyuria, while bacterial cultures remained negative. Nucleic acid amplification testing (NAAT) from urine was positive for N. gonorrhoeae, confirming the diagnosis. Given the absence of joint symptoms, purulent arthritis was considered unlikely, and leukocytoclastic vasculitis (LCV) was a differential diagnosis. However, the patient demonstrated significant improvement with ceftriaxone and doxycycline, supporting DGI as the primary diagnosis. He completed a seven-day course of ceftriaxone and oral doxycycline with full resolution of symptoms at follow-up. This case highlights an unusual presentation of DGI with isolated dermatologic manifestations and no tenosynovitis or arthritis. Methamphetamine use, previously linked to increased susceptibility to DGI, was noted in this patient. Negative blood and mucosal cultures emphasize the role of NAAT in diagnosing atypical DGI. Comparative case reviews demonstrate a wide spectrum of DGI presentations, reinforcing the need for early recognition. Clinicians should maintain a high index of suspicion for DGI, particularly in at-risk populations such as MSM, even in the absence of classic symptoms. Prompt diagnosis using NAAT and early antibiotic initiation are crucial for preventing complications. This case underscores the need for heightened awareness of atypical presentations to optimize patient outcomes.

Acceptability of Doxycycline Prophylaxis, Prior Antibiotic Use, and Knowledge of Antimicrobial Resistance Among Australian Gay and Bisexual Men and Nonbinary People

BACKGROUND

There is growing interest in novel sexually transmissible infection (STI) prevention strategies, including doxycycline postexposure prophylaxis (doxy-PEP). We assessed interest in doxy-PEP and other STI prevention strategies among gay and bisexual men and nonbinary people in Australia, as well as prior antibiotic use for STI prevention, and knowledge of antimicrobial resistance (AMR).

METHODS

We conducted a national, online survey in June to July 2023. Multivariable logistic regression was used to identify factors associated with the acceptability of doxy-PEP.

RESULTS

Of 2046 participants, 26.9% had been diagnosed with an STI in the previous year. Condoms were rated as an acceptable STI prevention strategy by 45.1% of the sample, STI preexposure prophylaxis by 54.0%, and doxy-PEP by 75.8%. Previous antibiotic use for STI prevention was reported by 7.5% of the sample, and 2.6% were currently using antibiotics for STI prevention. Over half the sample (62.1%) had some knowledge of AMR. Of those who knew something about AMR, 76.2% were concerned about it. Interest in using doxy-PEP was independently associated with previous use of antibiotics for STI prevention (adjusted odds ratio, 3.09; 95% confidence interval, 1.78-5.35; P < 0.001), whereas those who were concerned about AMR were less interested in it (adjusted odds ratio, 0.51; 95% confidence interval, 0.36-0.72; P < 0.001).

CONCLUSIONS

Doxycycline postexposure prophylaxis was highly acceptable to gay and bisexual men and nonbinary people in Australia, and few factors distinguished between interest in using it or not. We recommend community and professional discussion and education about the effective use of doxy-PEP, AMR, and who would most benefit from doxy-PEP.

Is doxycycline post-exposure prophylaxis being utilised in Germany? Insights from an online survey among German men who have sex with men

PURPOSE

Doxycycline post-exposure prophylaxis (Doxy-PEP) reduces the likelihood of Chlamydia and early syphilis by approximately two-thirds. Currently, data on the frequency of Doxy-PEP use in men who have sex with men (MSM) are limited. This study aimed to assess knowledge, attitude towards, and frequency of Doxy-PEP use among MSM in Germany.

METHODS

We conducted a national online survey in Germany from summer to fall 2023, recruiting MSM and transgender women. Participants were invited to complete the online survey through social media, online dating platforms, and print media advertisements with active recruitment and poster advertising in private practices, tertiary outpatient clinics, and MSM community events in Germany.

RESULTS

In total, 438 participants completed the survey and were included in the analysis, and 285 (65.1%) were living with the human immunodeficiency virus (HIV) or taking HIV-pre-exposure prophylaxis (PrEP). Overall, 170 participants (38.8%) had heard of Doxy-PEP, and 275 (62.8%) would consider taking it, but only 32 (7.3%) reported having ever taken Doxy-PEP. The most common reason for a negative attitude towards Doxy-PEP were apprehension about insufficient detailed information, and concerns about antibiotic resistance. Doxy-PEP users were more likely to be on HIV-PrEP, had a higher self-reported risk of bacterial sexually transmitted infections (STIs), and often had a history of bacterial STIs.

CONCLUSION

The study demonstrated high awareness and strong interest in Doxy-PEP among MSM in Germany, most of whom were living with HIV or taking HIV-PrEP; however, the actual usage of Doxy-PEP remains low in the summer and fall of 2023.

Utilization of Doxycycline Postexposure Prophylaxis at a Midwestern United States HIV/PrEP Clinic

Appropriate, protocol-adherent, doxycycline postexposure prophylaxis prescribing occurred for 70% of prescriptions from our clinic. Most of the nonadherent prescribing was due to missed sexually transmitted infection screenings (89%). As utilization of doxycycline postexposure prophylaxis continues to increase, it is necessary to ensure appropriate follow-up and monitoring.

Forty years of HIV infection and AIDS in Taiwan: Reflection on the past and looking toward the future

We review the epidemiology, policies, and control programs of HIV infection in Taiwan in the past 40 years since the first case of HIV infection was diagnosed in 1984. With the introduction of combination antiretroviral therapy (ART) in Taiwan in 1997, the incidences of HIV-related opportunistic illnesses and mortality have significantly declined. However, despite improved access to HIV testing and treatment, late presentation of HIV infection remains common. Unprotected sex, particularly among men who have sex with men, continues to be the leading risk for HIV transmission after implementation of harm reduction program to control an outbreak of HIV infection among people who inject drugs that occurred in 2003-2007. The sequential introduction of well-tolerated, effective, single-tablet antiretroviral regimens has facilitated the implementation of "treat-all" policy in 2016, rapid ART initiation within 7 days of diagnosis in 2018, and same-day ART initiation in 2021 when immunochromatography was used for rapid confirmation of HIV infection. Government-funded pilot program of pre-exposure prophylaxis for HIV infection, which was launched in 2016 followed by wider enrollment of people at high risk for HIV acquisition in 2018, have contributed to sustained declines of the incidence of HIV infection since 2018, along with high rates of linkage to HIV care, ART initiation, viral suppression, and retention in care in Taiwan. Challenges remain to achieve HIV elimination and long-term successful management of HIV infection, which include stigma and discrimination, late presentation of HIV infection, and accelerated ageing with increasing rates of co-morbidities among people with HIV.

Doxycycline as Post-Exposure Prophylaxis: Awareness, Beliefs, and Interest Among Patients with and at Risk for HIV

Recent studies have demonstrated the efficacy of doxycycline as post-exposure prophylaxis (doxy-PEP) for sexually transmitted infection (STI) prevention, but little is known regarding patient beliefs and interest in doxy-PEP. We conducted a cross-sectional survey of adults (≥ 19 years) receiving care for HIV treatment (PWH) or prevention (pre-exposure prophylaxis, PrEP) between May-October 2023. The 32-question survey was organized into three parts: doxy-PEP awareness/beliefs/interest/concerns, sexual history, and demographics. Fishers Exact and Wilcoxon rank sum tests were used to compare responses between groups. Multivariate logistic regression identified predictive factors for doxy-PEP interest and concern(s). 166 participants completed the survey. Mean age was 43 years, 83% were male, 22% Black, and 13% Hispanic. Forty-one participants (25%) were on PrEP. Most respondents (75%) were unaware of doxy-PEP. Factors associated with doxy-PEP interest were respondents prescribed PrEP (aOR 2.67; 95% CI, 1.15-6.21) and belief of high risk for STI (aOR, 4.50; 95% CI, 2.24-9.07). Higher doxy-PEP concerns were associated with age ≤40 years (aOR, 3.10; 95% CI, 1.47-6.52), > high school education (aOR, 3.47; 95% CI, 1.64-7.33), and belief of high risk for STI (aOR, 2.58; 95% CI, 1.21-5.50). In this single-site cohort survey study, most respondents were unaware of doxy-PEP but expressed interest and low levels of overall concern. Clinicians should offer doxy-PEP access to all patients at high risk for STIs or requesting the treatment after shared decision-making discussions.

Comparing Men Who Have Sex With Men Only and Men Who Have Sex With Men and Women Visiting a Public Sexually Transmitted Infection Clinic

BACKGROUND

Men reporting same-sex behaviors are disproportionately impacted by sexually transmitted infections (STIs). Differences in clinical characteristics and STIs in men who have sex with men only (MSMO), with men and women (MSMW), and with women only (MSW) are not well described.

METHODS

First visits to 2 Baltimore City STI clinics 2011-2016 from MSMO and MSMW compared with an age-matched random sample of MSW were analyzed. Acute STI (aSTI) included chlamydia, gonorrhea, nongonococcal urethritis, and primary or secondary syphilis. χ2 Tests and logistic regression examined associations.

RESULTS

Among N = 1226 MSMO, N = 491 MSMW, and N = 1717 MSW, most identified as Black/African American; mean age (29.8 years) was similar across groups. The percentages of MSMW, MSMO, and MSW who reported ≥2 partners in the last 6 months were 73.5%, 67.2%, and 60.3%, respectively. "Always" condom use was reported by 20.4%, 17.4%, and 14.1% of MSMW, MSMO, and MSW. Overall HIV prevalence was 13.8%. Among those tested, urogenital chlamydia prevalence rates were 21.7%, 8.3%, and 3.9% ( P ≤ 0.01) in MSW, MSMW, and MSMO. Urogenital gonorrhea prevalence was 11.6%, 7.7%, and 8.3% in MSMW, MSW, and MSMO, respectively. Extragenital STI (range, 2.7%-21.9%), nongonococcal urethritis (25.2%), and primary or secondary syphilis (5.3%-5.7%) positivity was similar in MSMW and MSMO. Older age was inversely associated with STI diagnosis in MSW and MSMO only; consistent condom use was protective against aSTI in MSW (adjusted odds ratio, 0.60; P < 0.01) and MSMW (adjusted odds ratio, 0.54; P = 0.03) only.

CONCLUSIONS

Differences in behaviors and clinical characteristics associated with aSTI suggest that MSMO, MSMW, and MSW have diverse sexual health needs and may require tailored interventions to improve sexual health outcomes.

Doxycycline post-exposure prophylaxis among men who have sex with men and transgender women in Belgium: awareness, use and antimicrobial resistance concerns in a cross-sectional online survey

OBJECTIVES

We aimed to assess the awareness, willingness to use and use of doxycycline post-exposure prophylaxis (doxyPEP) among men who have sex with men (MSM) and transgender women (TGW) in Belgium. Additionally, we aimed to identify factors associated with doxyPEP use and concerns regarding antimicrobial resistance (AMR).

METHODS

Cross-sectional online survey among MSM and TGW in Belgium in April 2024. Participants were recruited through sexual networking applications and social media of community-based organisations. Numerical variables were compared with Wilcoxon rank-sum test and categorical variables with χ2 or Fisher's exact tests. Factors associated with doxyPEP use were assessed using logistic regression. Willingness to use doxyPEP and concerns about side effects/AMR were assessed before and after presenting a brief paragraph on the potential effects of doxyPEP on AMR.

RESULTS

875 individuals initiated the survey. Almost all identified as men (860/875, 98.3%) with a median age of 40 years (IQR 32-48), 40.4% (n=352/875) had heard of doxyPEP and 9.4% (n=82/875) had used it, among whom the majority used it within the previous 6 months (70/81, 86.4%). In multivariable logistic regression, doxyPEP use was associated with reporting ≥1 sexually transmitted infection (STI) in the previous 12 months, engagement in chemsex, HIV status and pre-exposure prophylaxis use, and education level.About 80% of the participants initially reported being willing to use doxyPEP, and about 50% reported being concerned about side effects. After reading about the potential effects of doxyPEP on AMR, willingness to use decreased to 60% and concerns of side effects/AMR increased to around 70%.

CONCLUSIONS

Approximately 1 in 10 MSM in Belgium reported using doxyPEP. A recent history of STIs and STI risk factors were positively associated with doxyPEP use. Importantly, concerns about AMR and side effect influenced willingness to use doxyPEP. If doxyPEP is introduced, informing patients about doxyPEP benefits and risks is crucial to enable informed decision-making.

Efficacy of postexposure prophylaxis with doxycycline (Doxy-PEP) in reducing sexually transmitted infections: a systematic review and meta-analysis

OBJECTIVES

This systematic review aimed to identify the efficacy, adherence, safety and impact on antimicrobial resistance of postexposure prophylaxis with doxycycline (Doxy-PEP) in different populations.

METHODS

We searched MEDLINE (via PubMed), Embase and Cochrane CENTRAL databases from inception to 29 May 2024. Two reviewers independently screened the studies and extracted data. We included randomised clinical trials that evaluated the efficacy of Doxy-PEP within 72 hours after condomless sex. A random-effects meta-analysis was conducted to compare the risk of bacterial sexually transmitted infections (STIs) between Doxy-PEP and no prophylaxis. The risk of bias was assessed with the risk-of-bias tool for randomized trials (RoB 2) and the certainty of evidence (CoE) with Grading of Recommendations Assessment, Development and Evaluation (GRADE).

RESULTS

Four studies were included in the systematic review, totalling 1727 participants. Studies were conducted between 2015 and 2022. Most participants (73%) were men who have sex with men, and the median age of participants varied from 24 to 43 years. Doxy-PEP reduced the risk of having any bacterial STI in different populations by 46% (hazard ratio (HR) 0.54; 95% CI 0.39 to 0.75; CoE moderate), the risk of chlamydia by 65% (relative risk (RR) 0.35; 95% CI 0.15 to 0.82; CoE low) and syphilis by 77% (RR 0.23; 95% CI 0.13 to 0.41; CoE high), without significant effect for risk of gonorrhoea infection (RR 0.90; 95% CI 0.64 to 1.26; CoE very low). The self-reported adherence rate of Doxy-PEP was approximately 80% and one drug-related serious adverse event was reported.

CONCLUSION

Doxy-PEP reduced the incidence of chlamydia and syphilis infections. No significant reduction in gonorrhoea infection was observed. This strategy seems promising for some high-risk groups; however, there is still a lack of information on the induction of bacterial resistance and long-term adverse events.

PROSPERO REGISTRATION NUMBER

CRD42023454123.

Antimicrobial Resistance in Curable Sexually Transmitted Infections

PURPOSE OF REVIEW

Antimicrobial resistance in sexually transmitted infections (STIs) has become an urgent global public health threat, raising the specter of untreatable infections. This review summarizes the determinants of resistance among the five most common curable STIs Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma genitalium, Treponema pallidum, and Trichomonas vaginalis, as well as strategies to mitigate the spread of resistance.

RECENT FINDINGS

Genetic mutations are key drivers of resistance for N. gonorrhoeae and M. genitalium. Resistance in T. vaginalis can also occur because of genetic mutations, yet differential regulation of genes critical in antibiotic metabolism as well as co-infection with organisms that inactivate therapy play important roles. While resistance in C. trachomatis and T. pallidum has not been a substantial clinical concern, resistance selection via the continued widespread use of antimicrobials remains possible. While resistance determinants are diverse and differ by pathogen, the strategies required to mitigate the continued emergence of resistance are similar: prevention of infection and treatment diversification. Underpinning those strategies, surveillance remains essential for monitoring and responding to the threat of drug-resistant infections.