Enhancing the Control of Syphilis Among Men Who Have Sex With Men by Focusing on Acute Infectious Primary Syphilis and Core Transmission Groups

Potential mechanisms of Treponema pallidum breaching the blood-brain barrier

Syphilis, a sexually transmitted disease caused by Treponema pallidum subsp. pallidum (T. pallidum), can lead to a complication known as neurosyphilis. Neurosyphilis affects multiple components of the nervous system, including the meninges, blood vessels, brain parenchyma, and others, significantly impacting the central nervous system (CNS). Despite the effective control of syphilis spread by antibiotics, recent years have seen a resurgence in incidence among high-risk populations. The blood-brain barrier (BBB) is a critical defense for the CNS, preventing toxins and pathogens, including viruses, from entering and ensuring CNS function. The exact mechanisms of how T. pallidum penetrates the BBB are still not fully understood. Extensive research suggests that T. pallidum can disrupt endothelial cells and intercellular junctions, as well as induce abnormal activation of immune cells and aberrant cytokine expression, potentially facilitating its breach of BBB. Based on current research, we focus on the detrimental effects of cytokines on BBB integrity. We have also summarized the pathways T. pallidum uses to penetrate cellular barriers. Understanding the interaction between T. pallidum and the BBB is essential for revealing neurosyphilis pathogenesis and developing new therapies. DATA AVAILABILITY: Data used to support the findings of this study are included in the article.

Position statement of the German STI Society on the prophylactic use of doxycycline to prevent STIs (Doxy-PEP, Doxy-PrEP)

Over the past two decades, there has been a rise in the incidence of syphilis, particularly among men who have sex with men (MSM). This has sparked interest in studying the prophylactic use of doxycycline to prevent syphilis and other sexually transmitted infections (STIs), commonly referred to as Doxycycline Pre- or Post-Exposure Prophylaxis (Doxy-PrEP, Doxy-PEP). At the same time, demand from potential users for this preventive measure is increasing. Several randomized controlled trials have demonstrated that the prophylactic use of doxycycline in MSM and trans women using HIV pre-exposure prophylaxis (HIV-PrEP) or living with an HIV infection effectively reduces the risk of syphilis and chlamydia infections. At present, however, unresolved questions remain, particularly regarding implications of a broad implementation of prophylactic doxycycline to prevent STIs on tetracycline and other antimicrobial resistance in bacterial STIs, non-STI-related bacterial pathogens, and the microbiome. In response to the increasing demand and the challenge of balancing effectiveness, safety, and the risk of promoting antibiotic resistance, the German STI Society (DSTIG) has issued a position statement, providing specific recommendations regarding potential indications, criteria, and occasions for the use of doxycycline in STI prevention. These recommendations are based on current evidence and expert opinion.

Stellungnahme der Deutschen STI-Gesellschaft zur antibiotischen STI-Prophylaxe mit Doxycyclin (Doxy-PEP, Doxy-PrEP): Position Statement of the German STI Society on the Prophylactic Use of Doxycycline to Prevent STIs (Doxy-PEP, Doxy-PrEP)

Seit etwa zwei Jahrzehnten ist eine Zunahme der Syphilisinzidenz zu beobachten, insbesondere unter Männern, die Sex mit Männern haben (MSM). Diese Entwicklung hat zu einem wachsenden Interesse an Studien zur prophylaktischen Anwendung des Antibiotikums Doxycyclin zur Vermeidung von Syphilisinfektionen und anderen sexuell übertragbaren Infektionen (STI), international meist als Doxycyclin‐Prä‐ beziehungsweise Post‐Expositionsprophylaxe (Doxy‐PrEP, Doxy‐PEP) bezeichnet, geführt. Zugleich steigt die Nachfrage seitens potenzieller Nutzer nach dieser präventiven Maßnahme.

Mehrere randomisierte kontrollierte Studien haben gezeigt, dass die prophylaktische Anwendung von Doxycyclin bei MSM und Trans‐Frauen mit HIV‐PrEP‐Gebrauch oder bekannter HIV‐Infektion das Risiko einer Syphilis‐ und Chlamydien‐Infektion wirksam reduziert. Zum gegenwärtigen Zeitpunkt bestehen jedoch noch offene Fragen, insbesondere hinsichtlich der möglichen Auswirkungen einer breiten Anwendung der antibiotischen STI‐Prophylaxe mit Doxycyclin auf Tetrazyklin‐ und andere antimikrobielle Resistenzen bei bakteriellen STI, anderen bakteriellen Pathogenen und Bakterien des Mikrobioms.

Angesichts der steigenden Nachfrage und der Herausforderung, eine Abwägung zwischen Wirksamkeit, Sicherheit und dem Risiko der Förderung von Antibiotikaresistenzen vorzunehmen, hat die Deutsche STI‐Gesellschaft (DSTIG) die vorliegende Stellungnahme erarbeitet. Diese enthält spezifische Empfehlungen zu potenziellen Indikationen, Kriterien und Anlässen für den Einsatz von Doxycyclin zur Prävention von STI. Die Empfehlungen basieren auf aktuellen Studienergebnissen und der Meinung von Fachpersonen.

Epidemiology and determinants of reemerging bacterial sexually transmitted infections (STIs) and emerging STIs in Europe

In this scoping review, we offer a comprehensive understanding of the current and recent epidemiology, challenges, and emerging issues related to bacterial sexually transmitted infections (STIs) in the WHO European Region. We endeavour in collating data from both EU/EEA and non- EU/EEA countries, thereby giving a complete picture of the region which highlights the higher notification rates in Northern and Western countries than other regions, likely due to differences in testing, access to testing, and surveillance capacity. We provide an up-to-date review on the current knowledge of determinants and persistent inequities in key populations as well as the use of molecular epidemiology for identifying transmission networks in gonorrhoea and syphilis, and detecting chlamydia mutations that evade molecular diagnosis. Finally, we explore the emerging STIs in the region and the evolving transmission routes of food and waterborne diseases into sexual transmission. Our findings call for harmonized STI surveillance systems, proactive strategies, and policies to address social factors, and staying vigilant for emerging STIs.

Treponema pallidum PCR screening at mucosal sites of asymptomatic men who have sex with men taking HIV pre-exposure prophylaxis

Early detection and treatment of syphilis will reduce the infectious period and transmission. We aimed to determine whether screening men who have sex with men (MSM) taking HIV pre-exposure prophylaxis (PrEP) for syphilis using Treponema pallidum polymerase chain reaction (PCR) could detect syphilis before the appearance of syphilis antibodies in serology. MSM attending 3-monthly PrEP clinic visits in Melbourne, Australia, were screened with a PCR assay targeting the polA gene of T. pallidum from an anal swab and an oral rinse between November 2019 and March 2020. Participants were serologically screened for syphilis using chemiluminescence immunoassay. A total of 309 asymptomatic participants provided an anal swab and oral rinse sample for T. pallidum PCR screening. Two syphilis cases (0.6%) were detected: one man had a positive serology only; another man had T. pallidum detected by PCR from an anal swab and a positive serology. PCR positivity was 0.3% (n = 1) for anal swabs and 0% (n = 0) for oral rinse. In this study, T. pallidum PCR screening at routine PrEP clinic visits did not identify additional cases of early syphilis over serological screening performed at these visits. IMPORTANCE With the ongoing syphilis epidemic in men who have sex with men (MSM), we investigated the role of using Treponema pallidum polymerase chain reaction (PCR) testing at the oral cavity and anus in MSM taking pre-exposure prophylaxis for the early detection of syphilis. We evaluated whether the PCR tests from these mucosal sites can detect syphilis infection early, before the development of syphilis antibodies in serology. Our study found two syphilis cases among 309 MSM, and only one syphilis case had a positive anal PCR swab, although serology was positive. We conclude that additional PCR testing is likely to be expensive and would not be cost effective for individuals who regularly screen for syphilis. However, future studies with a larger sample size are required.

Lifetime prevalence of syphilis infection among predominantly Black sexual and gender minorities living with HIV in Atlanta, Georgia: a cross-sectional analysis

OBJECTIVES

Syphilis infection disproportionately impacts Black sexual and gender minorities (SGM) in the United States. The extent of this impact among those living with HIV has been minimally examined. This study sought to examine lifetime syphilis prevalence and associated factors in a community sample of predominantly Black SGM living with HIV in the Southeastern US.

DESIGN

Participants (N = 174) enrolled in a stigma-mitigation trial for people living with HIV in Atlanta, Georgia, completed a sub-study involving testing for Treponema pallidum antibodies, indicative of lifetime syphilis infection. We performed chi-square and Fisher's exact tests to assess sociodemographic and healthcare differences by presence/absence of lifetime syphilis infection.

RESULTS

Most participants identified as non-Hispanic Black (n = 142/174; 81.6%) and cisgender male (n = 146/174; 83.9%). More than two thirds (n = 120/174) identified as gay/homosexual. We documented a 55.7% (n = 97/174) lifetime prevalence of syphilis infection and observed differences by sexual identity, with 77.3% (n = 75/97) of those screening positive reporting gay/homosexual identity relative to 58.4% (n = 45/77) of those screening negative (chi-square[1] = 7.8, p < 0.010).

CONCLUSION

Findings underscore how syphilis prevention efforts have missed the most marginalized, warranting a renewed, comprehensive strategy for improving the sexual health of Black SGM. Embedding targeted, respectful community engagement, expanded testing access, and healthcare provider training into broader sexual health and psychosocial wellness efforts is needed.

Syphilis: recommendations for dermatologists on a resurgent epidemic

Despite reaching historical lows in the early 2000s, cases of both primary and secondary syphilis and congenital syphilis have increased dramatically in the U.S. over the last decade. In the U.S., the current syphilis epidemic is disproportionately impacting communities that have been historically underserved in medicine. These include men who have sex with men, especially those infected with HIV; people of color; and reproductive-age women with poor access to prenatal care. With syphilis now being more commonly diagnosed in non-STI than STI clinics in all genders, and since primary and secondary syphilis and congenital syphilis present with characteristic mucocutaneous manifestations, dermatologists are in a position to help reduce the advance of this preventable epidemic, by actively considering this diagnosis and incorporating syphilis screening into their practice. Herein, we delineate strategies by which dermatologists can contribute to this critical effort in their roles as clinicians, public health advocates, and researchers. In particular, we discuss the rapidly changing demographics of syphilis, nuances in serologic testing and treatment, strategies to increase public healthcare access and equity in these underserved populations, and research gaps in this field.

Primary syphilis without chancre – A case report of rare syphilitic balanitis of Follmann

Introduction

Syphilitic balanitis of Follmann (SBF) is a rare condition of primary syphilis which is characterized by any kind of balanitis with or without chancre on the penis combined with the presence of swollen inguinal lymph nodes confirmed by the finding of Treponema pallidum in the lesions or by the positive serological syphilitic testing. Timely identification of the SBF is very important in properly treating the disease stopping the spread of syphilis.

Case presentation

A 42year-old heterosexual male patient came to our clinic and complained of a painless, hard erythema nodule with a whitish scale in his coronal sulcus of the penis for about a week. The dermatologic examination revealed an infiltrative, hard erythematous lesion surrounding the coronal sulcus of the patient’s penis, with mild erosion and a small amount of exudation. There was a whitish pseudomembrane-like covering on the surface of the erythematous lesion in the coronal sulcus, which is mimicked as candidal balanitis. The result of the fungus microscopic examination was negative, while the laboratory findings showed positive results in serologic syphilitic testing. The patient was diagnosed with primary syphilis and intramuscularly treated with a dose of benzylpenicillin of 2.4 million units. The patient’s skin lesions disappeared completely 60 days after penicillin treatment.

Conclusion

To our knowledge, this is the first SBF case reported in China. Syphilitic balanitis of Follmann may have variable clinical appearances. We emphasize that when balanitis with risky sexual activities or with sexually transmitted diseases, the diagnosis of SBF should be kept in mind.

A cross-sectional survey on attitudes of men who have sex with men towards anal self-examination for detection of anal syphilis

Studies suggest men who have sex with men (MSM) practising receptive anal sex are more likely to present with secondary syphilis, implying primary anorectal lesions are likely to be missed. If men could detect anorectal lesions in the primary stage by regular anal self-examination (ASE), transmission could be reduced by early diagnosis and treatment. We aimed to explore the attitudes of MSM on performing ASE to detect primary anorectal syphilis. An online anonymous cross-sectional survey among MSM over 18 years of age living in Australia, was conducted between July and November 2020 and recruitment was from a sexual health clinic and social media. A total of 568 MSM completed the survey (median age: 34 [IQR 27–45]): 32% (183) had previously performed ASE. Among 66% (374) who had never performed ASE, 68% (250) would consider performing ASE in the future with a preferred median frequency of 2 times per 4 weeks (IQR 1–4), whilst men who were already performing ASE were performing it at median 1 per 4 weeks (IQR 0.2–3). Almost two-thirds of MSM who had never performed ASE were willing to adopt ASE practice in the future. Studies are required to determine the effectiveness of ASE for syphilis detection.

Repeat Syphilis Among HIV-Infected Men in Florida and Louisiana 2000-2018: Implications for Screening Recommendations

Syphilis rates have continued to rise in the United States. Florida and Louisiana consistently report high numbers of cases. We evaluated rates of reinfection to see if frequent rescreening might lead to earlier treatment and prevent infections. All syphilis records of all stages for males and females aged 15-70 years from the Florida and Louisiana Departments of Health surveillance databases 2000-2018 were evaluated. The first episode of syphilis during this period was considered the initial diagnosis for each person. Demographics of cases and repeaters (individuals reported with two or more cases of syphilis) were examined. Percentages of syphilis cases from repeaters by year were calculated as were percentages from HIV+ males. During 2000-2018, 124,827 syphilis cases were reported from 107,405 individuals: 73,811 (68.7%) males; 33,594 (31.3%) females. There were 12,545 individuals (repeaters) with two or more syphilis diagnoses (n = 17,422 cases; range, 2-10). From 2010 to 2018, repeaters accounted for steadily increasing percentage of all syphilis reported: 2010 (11%), 2013 (16%), 2015 (20%), and 2018 (26%). Among HIV+ male cases the percentage from repeaters also increased: 2010 (28%), 2013 (35%), 2015 (42%), and 2018 (50%). In 2018, 19% of all cases (n = 2455) were from HIV+ males who had a previous syphilis diagnosis. Among HIV+ males diagnosed with syphilis in 2015, 34% had a repeat syphilis diagnosis within 3 years. Most syphilis diagnosed in Florida and Louisiana was among persons infected for the first time. However, some subgroups could possibly benefit from more frequent screening. Males living with HIV who had a prior syphilis diagnosis were at very high risk of repeat infection.

Treponema pallidum detection in lesion and non-lesion sites in men who have sex with men with early syphilis: a prospective, cross-sectional study

BACKGROUND

Syphilis transmission is increasing, and precisely how Treponema pallidum is transmitted sexually from person to person is unclear. We aimed to determine the frequency of T pallidum shedding from potentially asymptomatic sites and the stage of infection at which shedding is most frequent in men who have sex with men (MSM), who have been disproportionately affected by syphilis.

METHODS

We did a prospective, cross-sectional study in MSM recruited from Melbourne Sexual Health Centre (Melbourne, VIC, Australia). Men were eligible if they were aged 18 years or older, reported sex with men during the past 12 months, and had laboratory confirmed primary, secondary, or early latent syphilis, consistent with Australian definitions. Primary and secondary syphilis lesions were swabbed and non-lesion samples were collected via oral rinse, oral cavity swab, anal canal swab, urine, and semen. Samples were tested for T pallidum using PCR assays targeting polA (lesion and non-lesion samples) and 47 kDa (non-lesion samples only) gene targets. The primary outcome was the proportion of men with T pallidum detected from potentially asymptomatic sites-namely, the mouth, anus, urethra, and semen.

FINDINGS

Between Nov 30, 2015, and May 23, 2019, 246 MSM were screened for inclusion, of whom 200 had serologically confirmed early syphilis and were included in the study: 54 (27%) of 200 had primary syphilis, 93 (47%) had secondary syphilis, and 53 (27%) had early latent syphilis. T pallidum DNA was detected in 48 (24%; 95% CI 18·3-30·5) of 200 men by oral rinse or oral lesion swab, or both, of whom 24 had no oral lesions. Oral T pallidum detection was most frequent in those with secondary syphilis compared with those at other stages of disease (41 [44%] of 93 vs seven [7%] of 107; p<0·0001), and in men with rapid plasma reagin titres of 1/64 or higher compared with those with lower titres (37 [32%] of 117 vs 11 [13%] of 83; p=0·0026). T pallidum was detected by anal canal swab or anal lesion swab, or both, in 45 (23·0%; 95% CI 17·3-29·5) of 196 men with available samples, of whom ten had no anal lesion. Furthermore, T pallidum was detected in urine samples of 12 (6·1%, 3·2-10·3) of 198 men and in semen samples from six (12·0%, 4·5-24·3) of 50 men who provided samples. Among the 93 men with secondary syphilis, 69 (74%) had T pallidum detected at any site, and 24 (26%) had detection at two or more separate sites. Among the 54 men with primary syphilis, 49 (91%) had T pallidum detected at any site, and 11 (20%) had detection at two or more separate sites. Among the 53 men with early latent syphilis, four (8%) had T pallidum detected at any site and none had T pallidum detected at two or more separate sites.

INTERPRETATION

Unrecognised oral and anal shedding of T pallidum occurs in MSM with early syphilis, most frequently in those with secondary syphilis, suggesting secondary syphilis is the most infectious stage and that earlier detection and treatment of syphilis to prevent progression to the secondary stage might improve syphilis control. Future research is needed to ascertain the contribution of shedding of T pallidum from non-lesion sites to transmission of syphilis.

FUNDING

Australian National Health and Medical Research Council.

Clinical and laboratory features of 244 men with primary syphilis: a 5-year single-centre retrospective study

BACKGROUND

Syphilis incidence has exponentially increased in recent decades, particularly among men who have sex with men (MSM). Primary syphilis is characterised by a chancre appearing at the site of Treponema pallidum (TP) inoculation. Atypical morphological variants of syphilitic chancre are frequent. Clinical suspicion must be confirmed either by the demonstration of TP within the lesion through direct tests, such as dark field microscopy (DFM) or T. pallidum nucleic acid amplification technique (TP-NAAT), or by serological tests.

OBJECTIVES

To analyse the clinical features, the sexual behaviour and the role of diagnostic tests in a cohort of men with primary syphilis in Milan.

METHODS

Epidemiological, clinical and laboratory data of male patients with primary syphilis seen at the STI Center of the University of Milan between 2015 and 2019 were retrospectively evaluated. Diagnosis was confirmed by at least one positive diagnostic test of either DFM, TP-NAAT or serology.

RESULTS

Among a total of 244 patients, 160 (65.6%) were MSM and 32 (13.1%) were living with HIV. One hundred twenty-four (50.8%) patients had a clinically atypical chancre. Chancres were exclusively extragenital in 30 (12.3%) patients, with MSM being more commonly affected (MSM vs heterosexuals: 16.3% vs 4.8%, respectively; p=0.012), and anal region the most frequently involved site. Chancres were multiple in 68/242 (28.1%) patients and morphologically atypical in 76/244 (31.1%). Diagnosis was obtained by (1) both serology and direct methods in 158/244 patients (64.7%), (2) serology solely in 47/244 (19.3%) and (3) direct methods solely in 39/244 (16%). DFM yielded positive results in 83/139 (59.7%) patients, while TP-NAAT gave positive results in 114/121 (94.2%) patients.

CONCLUSIONS

Patients with primary syphilis frequently present with morphologically atypical chancres. Furthermore, MSM commonly exhibit extragenital involvement. A combined diagnostic approach including both direct and indirect tests is needed.

In Vitro Susceptibility of Treponema pallidum subsp. pallidum to Doxycycline

Doxycycline is regarded as an effective therapy for early syphilis, and there is increasing interest in using doxycycline for prophylaxis of this infection. However, the MIC of doxycycline for Treponema pallidum subsp. pallidum has not been reported previously. In this study, an in vitro culture system was utilized to determine that the MIC of doxycycline is 0.06 to 0.10 μg/ml for four strains of T. pallidum subsp. pallidum (Nichols, SS14, UW231B, and UW249B). The Nichols strain cultured in vitro with doxycycline was also tested for infectivity in rabbits, and the minimum bactericidal concentration (MBC) was found to be ≤0.1 μg/ml using this method. The low MIC and MBC values are consistent with the previously demonstrated clinical efficacy of doxycycline for the treatment of early syphilis. This study represents the first report of the in vitro susceptibility of T. pallidum to doxycycline, and the resulting information may be useful in the consideration of doxycycline for use in prevention of syphilis.