Search Results (12)

Background/Objectives: Q fever, caused by Coxiella burnetii, is a zoonotic disease usually treated with doxycycline, but alternative options are needed when doxycycline is unsuitable. This study evaluated inhaled liposomal ciprofloxacin (Apulmiq^®) as a post-exposure prophylaxis (PEP) compared with oral doxycycline in a common marmoset model. Methods: Marmosets were exposed to aerosolised C. burnetii and treated 24 h later with Apulmiq (0.8 mg/kg inhaled), doxycycline (6 mg/kg oral), or placebo for 7 days. Outcomes included fever, weight loss, bacterial burden, histopathology, liver enzymes, and immune responses. Results: Both treatments delayed fever onset and reduced disease severity versus placebo. Doxycycline prevented fever during treatment and significantly reduced bacterial loads in the lungs and spleen by Day 28. Apulmiq slightly delayed the onset of fever and reduced early bacteraemia but was less effective at bacterial clearance. Immune analyses showed macrophage activation and elevation of IFN-γ during acute infection, and adaptive immune responses by Day 28. Conclusions: Inhaled Apulmiq provided partial prophylactic protection but did not achieve bacterial clearance. Doxycycline reduced bacterial burden but did not completely eliminate disease. Inhaled antibiotics may have potential for use as an alternative approach for PEP treatment, although further optimisation and investigation are needed. Full article

Sexually transmitted infections (STIs) remain a global health burden. Beyond classical pathogens, dermatophytes are increasingly identified within sexually linked transmission networks. Genital dermatophytosis is a superficial fungal infection of the genital area, primarily caused by anthropophilic and zoophilic dermatophytes. Recently, Trichophyton mentagrophytes genotype VII and Trichophyton indotineae have emerged as clinically significant dermatophytes, increasingly linked to human-to-human and sexually associated transmission within highly interconnected sexual networks. These infections are often marked by inflammatory, persistent, and treatment-refractory presentations, with prominent genital involvement and rising antifungal resistance—particularly to terbinafine—posing growing diagnostic and therapeutic challenges. Doxycycline post-exposure prophylaxis (Doxy-PEP) has recently emerged as a novel preventive strategy for bacterial STIs, involving the administration of 200 mg doxycycline within 24–72 h after activities associated with increased infection exposure, particularly among men who have sex with men (MSM) and transgender women. While effective in reducing infections such as syphilis and chlamydia, its broader implementation raises concerns regarding antimicrobial resistance. Chemsex is an increasingly prevalent behavioural phenomenon, defined as the intentional use of psychoactive substances during sexual activity to enhance or prolong the experience, particularly among MSM. It is associated with multiple adverse effects, including increased STI transmission, substance dependence, drug toxicity, psychological disturbances, and significant challenges in treatment adherence and healthcare engagement. This review aims to provide a comprehensive and clinically oriented overview of emerging trends in STIs, with a particular focus on dermatophyte infections as pathogens with potential sexually associated transmission, alongside evolving prevention strategies and behavioral factors influencing transmission. Full article

Objective: To explore healthcare professionals’ beliefs and concerns about doxyPEP by systematically reviewing the literature. Method: A systematic review of three bibliographical databases (CINAHL, EMBASE and MEDLINE) and MedRxiv in August 2024, updated in February 2026 explored healthcare professionals’ beliefs and concerns about doxyPEP. Three researchers independently reviewed full-text manuscripts for eligibility and narratively synthesized data. We used the Joanna Briggs Institute toolkit to assess risk of bias. This review was registered on PROSPERO (ID:CRD42024570646). Results: Eight manuscripts were included in the final review: five cross-sectional studies, two qualitative studies, and one mixed method study from the USA (n = 5), Australia (n = 1), Kenya (n = 1), and the UK (n = 1) published between 2020–2025 and including 1840 healthcare professionals. Healthcare professionals recognised the high burden of bacterial STIs and believed that doxyPEP should be made available to MSM. There was a strong willingness to provide doxyPEP to MSM with the support of national guidelines. Healthcare professionals suggest that implementing doxyPEP would be feasible with educational support, but were concerned about antimicrobial resistance, drug–drug interactions, pill burden, cost, implementation logistics and the effect on clinical service demands. They acknowledged the lack of research and access to doxyPEP for other groups, specifically trans people and cis-gendered women. They also highlighted the need for community involvement in the implementation of doxyPEP. Conclusions: This review highlights that healthcare professionals were willing and ready to provide doxyPEP; however, they have concerns including antimicrobial resistance, the effect on service capacity, and the lack of research on cis-gendered women and trans people. Patients and health professionals need to be involved in the implementation of doxyPEP. Full article

The rate of reported syphilis cases is increasing worldwide, particularly among men who have sex with men. In this scenario, malignant syphilis is a rare, severe form of secondary syphilis, typically observed in immunocompromised individuals and characterized by rupioid skin lesions, together with systemic symptoms that could lead to potentially life-threatening complications. We report the complex case of a 42-year-old man, previously diagnosed with HIV infection, presenting with a five-day history of fever and multiple lymphadenopathies. His immunovirological status was well controlled, and he was fully adherent to antiretroviral therapy. His clinical presentation was severe and ambiguous, with neurological involvement being progressively excluded. The diagnosis was confirmed by serological tests, while histopathological examination of an excised lymph node revealed disrupted architecture with multiple granulomas. Differential diagnosis, including lymphoma and other potential etiologies, was performed. After completion of antibiotic therapy, clinical symptoms completely resolved. No Jarisch–Herxheimer reaction occurred. We also provide an updated review of the current literature, with a focus on HIV coinfection, which is frequently associated with the development of malignant syphilis, and discuss the need for enhanced interventions to prevent sexually transmitted infections, as well as the importance of judicious use of doxycycline post-exposure prophylaxis. Full article

Syphilis, a global healthcare burden, is a sexually transmitted infection caused by the spirochete Treponema pallidum, a spiral-shaped, Gram-negative obligate human pathogen. Despite its easy identification and treatability, the disease affects over 50 million people worldwide, with 8 million new cases in the 15–49 age group annually, as per the WHO 2024 report. If left untreated, syphilis progresses through its primary, secondary, latent, and tertiary stages, causing severe complications like neurosyphilis, congenital syphilis, and organ damage. The first-line treatment, penicillin, faces challenges, including logistical issues, shortages, allergic reactions, and patient non-compliance. Secondary treatment options are sparse, and there are reported cases of T. pallidum strains resistant to those antibiotics. The absence of an effective vaccine for syphilis has led to efforts to control its spread through sexual education, condom usage, and post-exposure prophylaxis with doxycycline, which raises concerns about antimicrobial resistance (AMR). The continued reliance on penicillin and the increasing rates of doxycycline post-exposure prophylaxis (DoxyPEP) use have both contributed to concerns about AMR development. Recent works pointing to emerging antibiotic resistance and treatment failures highlight the urgent need for new antibiotics to manage syphilis effectively and reduce dependency on penicillin. This review has focused on the shortcomings and limitations of penicillin treatment, recently identified antimicrobial-resistant strains of T. pallidum, and case studies where its application failed to treat the disease adequately. Full article

Doxycycline is a semi-synthetic antibiotic in the tetracycline family. The three common subtypes of tetracyclines include naturally occurring, semi-synthetic, and new agents. Each subtype shares specific commonalities but is substantially different in various clinical applications. The mechanism of antimicrobial activity is the same across subtypes. The structural changes to the core naphthacene ring do not alter the mechanism of action but are thought to alter the rates of adverse effects and mechanisms of resistance. Tetracyclines as a class are known to cause fixed drug eruptions, but the majority of these adverse effects were associated with naturally occurring tetracyclines. Semi-synthetic tetracyclines have limited reports of fixed drug eruptions. Here, we present a case of fixed drug eruption in a patient who previously had multiple treatment courses with doxycycline. The case involves the use of doxycycline not for the treatment of an infection but as postexposure prophylactic (PEP) antibiotic therapy to prevent the acquisition of a sexually transmitted infection. Doxycycline PEP has been shown to reduce the rate of bacterial sexually transmitted infection in men who have sex with men (MSM). Doxycycline PEP is a single dose taken orally within 24–72 h of unprotected sexual intercourse. The dosing structure allows for ease of adherence but also repeatedly exposes individuals to doxycycline, putting them at risk for adverse events such as fixed drug eruptions, as illustrated by this case report. Full article

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. Full article

Anthrax is a fatal zoonotic disease caused by exposure to Bacillus anthracis spores. The CDC’s guidelines divide anthrax treatment into three categories according to disease progression: post-exposure prophylaxis (PEP), systemic, and systemic with a suspicion of CNS infection. While the prognosis for PEP or the early treatment of systemic anthrax is very good, ingress of the bacteria into the CNS poses a substantial clinical challenge. Here, we use rabbits to test the efficacy of a combined treatment of meropenem and doxycycline, which is the first choice in the CDC recommendations for treating systemic patients with an indication of CNS infection. In addition, we test the efficacy of the first-generation cephalosporin, cefazolin, in treating different stages of the disease. We found that the combination of doxycycline and meropenem is highly effective in treating rabbits in our inhalation model. Cefazolin was efficient only for PEP or systemic-stage treatment and not for CNS-infected animals. Our findings support the CDC recommendation of using a combination of doxycycline and meropenem for systemic patients with or without indications of CNS infection. We found that cefazolin is a decent choice for PEP or early-stage systemic disease but recommend considering using this antibiotic only if all other options are not available. Full article

Background: Since the implementation of pre-exposure prophylaxis (PrEP) in HIV prevention, a significant increase in the prevalence of other sexually transmitted infections (STIs) has been reported, especially among men who have sex with men (MSM). Doxycycline is being examined as a potential pharmacological agent in preventing these infections. This review aims to summarize available data on the effectiveness and potential side effects of doxycycline for the prevention of bacterial STIs. Methods: We reviewed the National Library of Medicine and the National Center of Biotechnology Information in order to find clinical trials and relevant observational studies regarding doxycycline usage in STI prophylaxis. Results: Doxycycline prophylaxis reduced the risk of acquiring chlamydia, syphilis, and, in a majority of the trials, the risk of gonorrhea. The clinical trials on doxycycline STI prophylaxis were underpowered to determine if doxycycline promotes the selection of resistance in Neisseria gonorrhoeae and Chlamydia trachomatis. Additionally, no serious side effects of this preventive measure have been reported. None of the studies aimed to compare the efficacy of post- and pre-exposure prophylaxis of STDs with doxycycline. Conclusions: The preliminary results regarding STI prophylaxis with doxycycline seem to be promising. Further research is needed to determine the potential risk of doxycycline prophylactic prescription. Full article

The timing of the initiation of antibiotic treatment has been shown to impact the clinical outcome of many bacterial infections, including Q fever. Delayed, suboptimal or incorrect antibiotic treatment has been shown to result in poor prognosis, resulting in the progression of acute disease to long-term chronic sequalae. Therefore, there is a requirement to identify an optimal, effective therapeutic regimen to treat acute Q fever. In the study, the efficacies of different doxycycline monohydrate regimens (pre-exposure prophylaxis, post-exposure prophylaxis or treatment at symptom onset or resolution) were evaluated in an inhalational murine model of Q fever. Different treatment lengths (7 or 14 days) were also evaluated. Clinical signs and weight loss were monitored during infection and mice were euthanized at different time points to characterize bacterial colonization in the lungs and the dissemination of bacteria to other tissues including the spleen, brain, testes, bone marrow and adipose. Post-exposure prophylaxis or doxycycline treatment starting at symptoms onset reduced clinical signs, and also delayed the systemic clearance of viable bacteria from key tissues. Effective clearance was dependent on the development of an adaptive immune response, but also driven by sufficient bacterial activity to maintain an active immune response. Pre-exposure prophylaxis or post-exposure treatment at the resolution of clinical signs did not improve outcomes. These are the first studies to experimentally evaluate different doxycycline treatment regimens for Q fever and illustrate the need to explore the efficacy of other novel antibiotics. Full article

Record-breaking and devastating rainfall events have occurred in the past decade. Rain and floods are considered the main risk factors for leptospirosis and several outbreaks have been reported following extreme weather events. In such situations, one possible intervention to prevent leptospirosis cases in high-risk groups is the use of chemoprophylaxis. However, not enough evidence of its effect is available. The objectives of this study were to review the literature on the current practices of chemoprophylaxis for leptospirosis and to explore, using a mathematical model, how various chemoprophylaxis scenarios may affect the progression of a leptospirosis outbreak. Twenty-six peer-reviewed publications were selected (10 quantitative studies, two systematic reviews and 14 articles of other types). Oral doxycycline was the most used antibiotic for chemoprophylaxis of leptospirosis. Post-exposure prophylaxis was assessed in four studies following a natural disaster. Although evidence of the effectiveness of post-exposure prophylaxis is inconsistent, the direction of association supported a protective effect for morbidity and mortality. The theoretical model showed how the assumed benefit of chemoprophylaxis was influenced by the time and rate of administration. Future models should consider the heterogeneity of affected communities, improved estimates of the effect of chemoprophylaxis on leptospirosis infection and disease, as well as potential detrimental impacts. Additional research is critical to provide clear evidence-based recommendations for leptospirosis control during an outbreak. The results of this study suggest that chemoprophylaxis may provide some protection in reducing the number of leptospirosis cases after a high-risk exposure; however, the effective benefit may depend on a variety of factors such as the timing and coverage of prophylaxis. The information summarized can be used to support decision-making during a high-risk event. Full article