Invasion of the central nervous system by Treponema pallidum: implications for diagnosis and treatment

Prevalence and Predictors of Oral Treponema pallidum Detection by Quantitative Polymerase Chain Reaction in Early Syphilis

BACKGROUND

Treponema pallidum prevalence and burden at oral and lesion sites in adults with early syphilis were assessed by quantitative polymerase chain reaction (qPCR). Factors associated with oral shedding were also examined.

METHODS

Pretreatment oral and lesion swabs were collected from adults with early syphilis in a US multicenter syphilis treatment trial. Oral swabs were collected in the presence and absence of oral lesions. Following DNA extraction, qPCR and whole-genome sequencing (WGS) were performed to assess burden and strain variability.

RESULTS

All 32 participants were male, mean age was 35 years, and 90.6% with human immunodeficiency virus (HIV). T. pallidum oral PCR positivity varied by stage: 16.7% primary, 44.4% secondary, and 62.5% in early latent syphilis. Median oral T. pallidum burden was highest in secondary syphilis at 63.2 copies/µL. Lesion PCR positivity was similar in primary (40.0%) and secondary syphilis (38.5%). Age 18-29 years was significantly associated with oral shedding (vs age 40+ years) in adjusted models. WGS identified 2 distinct strains.

CONCLUSIONS

T. pallidum DNA was directly detected at oral and lesion sites in a significant proportion of men with early syphilis. Younger age was associated with oral shedding. Ease of oral specimen collection and increased PCR availability suggest opportunities to improve syphilis diagnostic testing. Clinical Trials Registration. NCT03637660.

Sexually Transmitted Infections in People with Human Immunodeficiency Virus

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

Contribution of CNS and extra-CNS infections to neurodegeneration: a narrative review

Central nervous system infections have been suggested as a possible cause for neurodegenerative diseases, particularly sporadic cases. They trigger neuroinflammation which is considered integrally involved in neurodegenerative processes. In this review, we will look at data linking a variety of viral, bacterial, fungal, and protozoan infections to Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, multiple sclerosis and unspecified dementia. This narrative review aims to bring together a broad range of data currently supporting the involvement of central nervous system infections in the development of neurodegenerative diseases. The idea that no single pathogen or pathogen group is responsible for neurodegenerative diseases will be discussed. Instead, we suggest that a wide range of susceptibility factors may make individuals differentially vulnerable to different infectious pathogens and subsequent pathologies.

State-of-the-Art Review: Neurosyphilis

We review key concepts in the diagnosis, treatment, and follow-up of individuals with neurosyphilis. We describe the epidemiology of syphilis in the United States, highlight populations that are markedly affected by this infection, and attempt to estimate the burden of neurosyphilis. We describe the cardinal clinical features of early and late (tertiary) neurosyphilis and characterize the clinical significance of asymptomatic neurosyphilis in the antibiotic era. We review the indications for cerebrospinal fluid (CSF) examination and the performance characteristics of different CSF assays including treponemal and lipoidal antibodies, white cell count, and protein concentration. Future biomarkers and the role of imaging are briefly considered. We review preferred and alternative treatments for neurosyphilis and evidence for their use, including evidence for the use of enhanced intramuscular benzathine penicillin G to supplement intravenous penicillin.

ADAMTS5 Promotes Permeability of the Blood-Brain Barrier during Treponema pallidum Subspecies pallidum Invading the Central Nervous System

The pathogenesis of neurosyphilis remains unclear. A previous study found a noteworthy up-regulation of a disintegrin and metalloproteinase with thrombospondin type 1 motif 5 (ADAMTS5) gene in human brain microvascular endothelial cells cocultured with Treponema pallidum subspecies pallidum (Tp). To investigate the ADAMTS5 role in Tp invading the central nervous system (CNS), we conducted relevant experiments. Our study revealed that Tp caused an increase in human cortical microvascular endothelial cell/D3 (hCMEC/D3) barrier permeability and significantly enhanced ADAMTS5 expression. The heightened permeability of the hCMEC/D3 barrier was effectively mitigated by inhibiting ADAMTS5. During this process, Tp promoted interleukin-1β production, which, in turn, facilitated ADAMTS5 expression. Furthermore, Tp significantly reduced the glycocalyx on the surface of hCMEC/D3 cells, which was also ameliorated by inhibiting ADAMTS5. Additionally, ADAMTS5 and endothelial glycocalyx components notably increased in the cerebrospinal fluid of HIV-negative neurosyphilis patients. This research provided the first demonstration of the ADAMTS5 role in Tp invading the CNS and offered new insight into neurosyphilis pathogenesis.

Tryptophan-kynurenine metabolic pathway and daytime dysfunction in women with HIV

Sleep disturbances are prevalent in women with HIV (WWH). Tryptophan-kynurenine (T-K) pathway metabolites are associated with alterations in actigraphy derived sleep measures in WWH, although may not always correlate with functional impairment. We investigated the relationship between T-K pathway metabolites and self-reported daytime dysfunction in WWH and women without HIV (WWoH). 141 WWH on stable antiretroviral therapy and 140 demographically similar WWoH enrolled in the IDOze Study had targeted plasma T-K metabolites measured using liquid chromatography-tandem mass spectrometry. We utilized the daytime dysfunction component of the Pittsburgh Sleep Quality Index (PSQI) to assess functional impairment across HIV-serostatus. Lower levels of 5-hydroxytryptophan and serotonin were associated with greater daytime dysfunction in all women. In WWH, daytime dysfunction was associated with increased kynurenic acid (R = 0.26, p < 0.05), and kynurenic acid-tryptophan (KA-T) ratio (R = 0.28, p < 0.01). WWH with daytime dysfunction had a 0.7 log fold increase in kynurenic acid compared to WWH without daytime dysfunction. Kynurenic acid levels and the KA-T ratio were associated with daytime dysfunction in WWH but not in WWoH. Longitudinal studies are needed to establish a causal relationship and directionality between T-K metabolic changes and sleep impairment in WWH.

Syphilis for dermatologists: Current concepts

Dermatologists are familiar with the classic aspects of syphilis. Our objective in this update is to display novel features of sexually acquired syphilis, its pathophysiology, natural history, atypical clinical variants, skin of color, clinical pearls, and prospects. Textbook knowledge, congenital syphilis, epidemiology, and historical data are excluded.

Diagnostic value of cerebrospinal fluid chemokine c-x-c motif ligand 13 for neurosyphilis: A systematic review and meta-analysis

The diagnostic value of cerebrospinal fluid chemokine c-x-c motif ligand 13 (CSF CXCL13) for neurosyphilis was assessed by meta-analysis in this study. PubMed, Web of Science and Embase databases were searched to identify relevant articles by using MeSH and free terms of CXCL13 and neurosyphilis. A total of 720 syphilis and 338 neurosyphilis individuals in 6 articles were involved in this meta-analysis. The pooled sensitivity and specificity were 0.82 (95% confidence intervals (CI), 0.77-0.87) and 0.84 (95% CI, 0.79-0.87). The pooled positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio and the area under receiver operating characteristic curve were 5.10 (95% CI, 3.90-6.60), 0.21 (95% CI, 0.16-0.28), 24.00 (95% CI, 14.00-39.00) and 0.88 (95% CI, 0.84-0.90), respectively. In subgroup analysis, human immunodeficiency virus infection and diagnostic criteria for neurosyphilis were identified to be associated with heterogeneity. Based on limited evidence, CSF CXCL13 can be helpful in diagnosing neurosyphilis.

A patient with secondary syphilis following incomplete treatment of primary infection

Syphilis is a bacterial infection caused by Treponema pallidum and is primarily transmitted via skin-to-skin or mucosal contact during sexual encounters, or through vertical transmission during pregnancy. Cases continue to rise globally across various demographic groups despite effective treatment and prevention interventions. We discuss the case of a 28-year-old cisgender man who presented with secondary syphilis 1 month after being inadequately treated for primary syphilis. Individuals can present with symptoms and signs of syphilis to clinicians of various subspecialties due to diverse clinical presentation. All health-care providers should be able to identify the common and less common manifestations of this infection, and adequate treatment and follow-up are crucial to preventing serious sequelae. Novel biomedical prevention interventions, such as doxycycline post-exposure prophylaxis, are on the horizon.

Demystifying Ocular Syphilis - A Major Review

Syphilis, caused by the spirochaete, Treponema pallidum, continues to be a public health challenge globally with its rates steadily increasing in the past few years. The disease is transmitted through small breaks in the skin during sexual contact, or via congenital transmission in utero, either across the placenta or by contact with an active genital lesion during delivery. Estimated 5.7-6 million new cases are detected every year worldwide in the 15-49 years age group. An increased incidence has been reported in most populations with particular clusters in special groups like men who have sex with men, female sex workers, and their male clients. Ocular syphilis has a varied presentation and is considered a great mimicker in all cases of uveitis. The laboratory diagnosis of syphilis is predominantly based on serological tests including TPHA and VDRL. Parenteral penicillin is the cornerstone of treatment for all stages of ocular syphilis.

Manic Episodes in a Patient With Neurosyphilis Following Brief Discontinuation of Bipolar Medication

Bipolar disorder is a mood disorder resulting in episodes of either mania or hypomania. The episodes can manifest themselves as a period of abnormally and persistently elevated mood, abnormally and persistently increased activity or energy, distractibility, insomnia, grandiosity, flight of ideas, increased activity, pressured speech, and racing thoughts. Neurosyphilis is a progression of syphilis infection involving the brain, meninges, or spinal cord. The interaction between bipolar disorder and neurosyphilis has not been extensively studied, but it has been theorized that neurosyphilis can exacerbate mood disorders. This case study details a patient with concurrent late-onset bipolar disorder and neurosyphilis and how the discontinuation of bipolar medication resulted in an acute manic episode. In addition, this case underscores the importance of differentiating the presenting symptoms between bipolar disorder and neurosyphilis.

Diagnosis of neurosyphilis in HIV-negative patients with syphilis: development, validation, and clinical utility of a suite of machine learning models

Background

The ability to accurately identify the absolute risk of neurosyphilis diagnosis for patients with syphilis would allow preventative and therapeutic interventions to be delivered to patients at high-risk, sparing patients at low-risk from unnecessary care. We aimed to develop, validate, and evaluate the clinical utility of simplified clinical diagnostic models for neurosyphilis diagnosis in HIV-negative patients with syphilis.

Methods

We searched PubMed, China National Knowledge Infrastructure and UpToDate for publications about neurosyphilis diagnostic guidelines in English or Chinese from database inception until March 15, 2023. We developed and validated machine learning models with a uniform set of predictors based on six authoritative diagnostic guidelines across four continents to predict neurosyphilis using routinely collected data from real-world clinical practice in China and the United States (through the Dermatology Hospital of Southern Medical University in Guangzhou [659 recruited between August 2012 and March 2022, treated as Development cohort], the Beijing Youan Hospital of Capital Medical University in Beijng [480 recruited between December 2013 and April 2021, treated as External cohort 1], the Zhongshan Hospital of Xiamen University in Xiamen [493 recruited between November 2005 and November 2021, treated as External cohort 2] from China, and University of Washington School of Medicine in Seattle [16 recruited between September 2002 and April 2014, treated as External cohort 3] from United States). We included all these patients with syphilis into our analysis, and no patients were further excluded. We trained eXtreme gradient boosting (XGBoost) models to predict the diagnostic outcome of neurosyphilis according to each diagnostic guideline in two scenarios, respectively. Model performance was measured through both internal and external validation in terms of discrimination and calibration, and clinical utility was evaluated using decision curve analysis.

Findings

The final simplified clinical diagnostic models included neurological symptoms, cerebrospinal fluid (CSF) protein, CSF white blood cell, and CSF venereal disease research laboratory test/rapid plasma reagin. The models showed good calibration with rescaled Brier score of 0.99 (95% CI 0.98-1.00) and excellent discrimination (the minimum value of area under the receiver operating characteristic curve, 0.84; 95% CI 0.81-0.88) when externally validated. Decision curve analysis demonstrated that the models were useful across a range of neurosyphilis probability thresholds between 0.33 and 0.66 compared to the alternatives of managing all patients with syphilis as if they do or do not have neurosyphilis.

Interpretation

The simplified clinical diagnostic models comprised of readily available data show good performance, are generalisable across clinical settings, and have clinical utility over a broad range of probability thresholds. The models with a uniform set of predictors can simplify the sophisticated clinical diagnosis of neurosyphilis, and guide decisions on delivery of neurosyphilis health-care, ultimately, support accurate diagnosis and necessary treatment.

Funding

The Natural Science Foundation of China General Program, Health Appropriate Technology Promotion Project of Guangdong Medical Research Foundation, Department of Science and technology of Guangdong Province Xinjiang Rural Science and Technology（Special Commissioner）Project, Southern Medical University Clinical Research Nursery Garden Project, Beijing Municipal Administration of Hospitals Incubating Program.

Clinical evidence of human pathogens implicated in Alzheimer's disease pathology and the therapeutic efficacy of antimicrobials: an overview

A wealth of pre-clinical reports and data derived from human subjects and brain autopsies suggest that microbial infections are relevant to Alzheimer's disease (AD). This has inspired the hypothesis that microbial infections increase the risk or even trigger the onset of AD. Multiple models have been developed to explain the increase in pathogenic microbes in AD patients. Although this hypothesis is well accepted in the field, it is not yet clear whether microbial neuroinvasion is a cause of AD or a consequence of the pathological changes experienced by the demented brain. Along the same line, the gut microbiome has also been proposed as a modulator of AD. In this review, we focus on human-based evidence demonstrating the elevated abundance of microbes and microbe-derived molecules in AD hosts as well as their interactions with AD hallmarks. Further, the direct-purpose and potential off-target effects underpinning the efficacy of anti-microbial treatments in AD are also addressed.

Secondary Central Nervous System Demyelinating Disorders in the Elderly: A Narrative Review

Secondary demyelinating diseases comprise a wide spectrum group of pathological conditions and may either be attributed to a disorder primarily affecting the neurons or axons, followed by demyelination, or to an underlying condition leading to secondary damage of the myelin sheath. In the elderly, primary demyelinating diseases of the central nervous system (CNS), such as multiple sclerosis, are relatively uncommon. However, secondary causes of CNS demyelination may often occur and in this case, extensive diagnostic workup is usually needed. Infectious, postinfectious, or postvaccinal demyelination may be observed, attributed to age-related alterations of the immune system in this population. Osmotic disturbances and nutritional deficiencies, more commonly observed in the elderly, may lead to conditions such as pontine/extrapontine myelinolysis, Wernicke encephalopathy, and demyelination of the posterior columns of the spinal cord. The prevalence of malignancies is higher in the elderly, sometimes leading to radiation-induced, immunotherapy-related, or paraneoplastic CNS demyelination. This review intends to aid clinical neurologists in broadening their diagnostic approach to secondary CNS demyelinating diseases in the elderly. Common clinical conditions leading to secondary demyelination and their clinical manifestations are summarized here, while the current knowledge of the underlying pathophysiological mechanisms is additionally presented.

Syphilis

Syphilis is a sexually and vertically transmitted bacterial infection caused by the bacterium Treponema pallidum. Its prevalence is high in low-income and middle-income countries, and its incidence has increased in high-income countries in the last few decades among men who have sex with men. Syphilis is a major cause of adverse pregnancy outcomes in low-income and middle-income countries. Clinical features include a primary chancre at the point of inoculation, followed weeks later by the rash of secondary syphilis, a latent period, and in some cases, involvement of the eyes, CNS, and cardiovascular systems. It is diagnosed serologically. A single intramuscular dose of long-acting benzathine penicillin is recommended for people who have had syphilis for less than 1 year and longer courses for people with late latent syphilis. Control strategies include screening and treatment of all pregnant women, and targeted interventions for groups at high risk. Vaccine development, research on antibiotic prophylaxis, and digital messaging as prevention strategies are ongoing.

In Vitro Isolation of Treponema pallidum subsp. pallidum From Fresh and Frozen Needle Aspirates of Primary Experimental Syphilis Lesions

ABSTRACT

Isolation of Treponema pallidum subsp. pallidum strains still relies on rabbit intratesticular inoculation of clinical samples. In this article, we report an alternative isolation approach based on the inoculation of fresh and frozen needle aspirates of primary experimental lesions into culture plates suitable for in vitro propagation of the syphilis agent.

Otosyphilis

Otosyphilis can be challenging to diagnose, but, if left unrecognized, it may cause irreversible damage. An immunologic interplay between syphilis and human immunodeficiency virus (HIV) makes coinfection likely and may predispose people with HIV to neurosyphilis. In this study, we present a case of a man in his 50s with hearing loss and vertigo diagnosed with otosyphilis as well as a new diagnosis of HIV. This case and corresponding discussion serve to inform the noninfectious disease-trained clinician of the symptoms, diagnostics, and treatment options for otosyphilis as well as to discuss the relationship between HIV and syphilis and demonstrate the importance of disease recognition.

Otosyphilis: A rare case of reversible hearing loss in a young man with secondary syphilis

Background

Over the last decade, it has been noticed a significant increase in the number of cases of syphilis with a concurrent increased number of patients presenting with syphilis-related complications. Otosyphilis is a well-known complication of syphilis that most of the time, can lead to irreversible hearing loss, especially with delayed diagnosis and treatment. A high index of suspicion is needed for an accurate diagnosis of otosyphilis. Complete audiologic recovery is rare but still possible with the appropriate treatment.

Case report

Herein, we describe a case of reversible hearing loss secondary to otosyphilis in a young healthy man who was initially diagnosed and treated as a case of secondary syphilis, and presented later to the clinic with unilateral tinnitus and hearing loss. Audiology findings were consistent with asymmetric sensorineural hearing loss. Fortunately, complete recovery of hearing was achieved after treatment with a 14-day course of intravenous penicillin.

Conclusion

Otosyphilis is one of the rare presentations of syphilis; thus, the diagnosis is often missed or delayed. Prompt diagnosis and treatment can help prevent the occurrence of permanent hearing loss.

Immunization with a tri-antigen syphilis vaccine significantly attenuates chancre development, reduces bacterial load, and inhibits dissemination of Treponema pallidum

Syphilis continues to be a significant public health concern worldwide. The disease is endemic in many low- and middle-income countries, and rates have risen sharply in high-income countries over the last decade. The continued prevalence of infectious and congenital syphilis worldwide highlights the need for the development of an effective syphilis vaccine to complement public health measures for syphilis control. The complex, multi-stage course of syphilis infection necessitates a holistic approach to the development of an effective vaccine, in which immunization prevents both the localized stage of infection (typified by the highly infectious chancre) and the disseminated stages of infection (typified by the secondary rash, neurosyphilis, and destructive tertiary lesions, as well as congenital syphilis). Inhibiting development of the infectious chancre would reduce transmission thus providing community- level protection, while preventing dissemination would provide individual-level protection by reducing serious sequelae and may also provide community level protection by reducing shedding during secondary syphilis. In the current study we build upon prior investigations which demonstrated that immunizations with individual, well characterized T. pallidum TprK, TprC, and Tp0751 peptides elicits partial protection against infection in the animal model. Specifically, we show here that immunization with a TprC/TprK/Tp0751 tri-antigen cocktail protects animals from progressive syphilis lesions and substantially inhibits dissemination of the infection.

Identification and Functional Characterization of Peptides With Antimicrobial Activity From the Syphilis Spirochete, Treponema pallidum

The etiological agent of syphilis, Treponema pallidum ssp. pallidum, is a highly invasive “stealth” pathogen that can evade the host immune response and persist within the host for decades. This obligate human pathogen is adept at establishing infection and surviving at sites within the host that have a multitude of competing microbes, sometimes including pathogens. One survival strategy employed by bacteria found at polymicrobial sites is elimination of competing microorganisms by production of antimicrobial peptides (AMPs). Antimicrobial peptides are low molecular weight proteins (miniproteins) that function directly via inhibition and killing of microbes and/or indirectly via modulation of the host immune response, which can facilitate immune evasion. In the current study, we used bioinformatics to show that approximately 7% of the T. pallidum proteome is comprised of miniproteins of 150 amino acids or less with unknown functions. To investigate the possibility that AMP production is an unrecognized defense strategy used by T. pallidum during infection, we developed a bioinformatics pipeline to analyze the complement of T. pallidum miniproteins of unknown function for the identification of potential AMPs. This analysis identified 45 T. pallidum AMP candidates; of these, Tp0451a and Tp0749 were subjected to further bioinformatic analyses to identify AMP critical core regions (AMPCCRs). Four potential AMPCCRs from the two predicted AMPs were identified and peptides corresponding to these AMPCCRs were experimentally confirmed to exhibit bacteriostatic and bactericidal activity against a panel of biologically relevant Gram-positive and Gram-negative bacteria. Immunomodulation assays performed under inflammatory conditions demonstrated that one of the AMPCCRs was also capable of differentially regulating expression of two pro-inflammatory chemokines [monocyte chemoattractant protein-1 (MCP-1) and interleukin-8 (IL-8)]. These findings demonstrate proof-of-concept for our developed AMP identification pipeline and are consistent with the novel concept that T. pallidum expresses AMPs to defend against competing microbes and modulate the host immune response.

Clinical outcomes of HIV-syphilis coinfection among patients with no neurological symptoms: a retrospective cohort study

OBJECTIVE

Our objective was to describe and compare the occurrence of neurological outcomes and neurosyphilis in people living with HIV with incident syphilis and no neurological symptoms who underwent early screening for asymptomatic neurosyphilis (ANS) or regular clinical management without a lumbar puncture.

METHODS

This was a retrospective cohort study in a single referral centre of Sao Paulo, Brazil. Patients with incident syphilis diagnosed between January 2000 and August 2016 and meeting the adapted criteria for ANS investigation suggested by Marra et al. (CD4⁺ T-cell counts ≤350 cells/mm³ and/or venereal disease research laboratory test results ≥1:16) were identified. Those with no neurological symptoms and immediately referred for lumbar puncture were categorized as group 1, and those not referred for cerebrospinal fluid collection were categorized as group 2. We compared the occurrence of neurological symptoms and neurosyphilis diagnoses between the groups using incidence rates and Kaplan-Meier curves.

RESULTS

We included 425 participants with a median follow-up of 6 years. The incidence rate of neurological symptoms was 36.5/1000 person-years in group 1 and 40.6/1000 person-years in group 2 (incidence rate ratio [IRR] 0.90; 95% confidence interval [CI] 0.57-1.39; p = 0.62). The incidence rate of neurosyphilis was 15.0 cases/1000 person-years in group 1 and 6.7 cases/1000 person-years in group 2 (IRR 2.26; 95% CI 0.93-5.68; p = 0.05).

CONCLUSIONS

We found no statistically significant differences between groups in the incidence rates of neurological symptoms and neurosyphilis. Our findings support the current guidelines, which suggest a less invasive approach regarding ANS investigation among people living with HIV with incident syphilis.

Clinical features associated with neurosyphilis in people living with HIV and late latent syphilis

Background

The diagnosis of neurosyphilis is a challenge, and the criteria for deciding when to perform a lumbar puncture are still controversial, especially in people living with HIV with a late latent syphilis diagnosis.

Methods

Retrospective analysis of demographic, clinical, and laboratory data of people with HIV and documented late latent syphilis or syphilis of unknown duration with a cerebrospinal fluid VDRL test.

Results

122 patients were evaluated, of whom 52 had the diagnosis of neurosyphilis. Patients with and without neurosyphilis presented a similar viral load and lymphocyte CD4⁺ T-cell count. Neurological symptoms (OR 6.4, 95% CI 2.1–22.4; p < 0.01), serum VDRL titers of 1:32 (p<0.01), 1:64 (p = 0.055), and ≥1:128 (p < 0.001) were associated with neurosyphilis. Furthermore, serum VDRL ≥1:32 were associated with (OR 24.9, 95% CI 5.45–154.9; p < 0.001) or without (OR 6.5, 95% CI 2.0–29.2; p = 0.004) neurological symptoms with neurosyphilis; however, VDRL ≤1:16 with neurological symptoms can be associated with neurosyphilis (OR 7.6, 95% CI 1.03–64.3; p = 0.046).

Conclusion

Neurological symptoms, particularly headache, were predictors of neurosyphilis in people with HIV irrespective of their viral load and lymphocyte CD4⁺ T-cell count in late latent syphilis. A serum VDRL ≥1:32 increased the risk of neurosyphilis in patients with or without any symptoms.

Asymptomatic Neurosyphilis in HIV infected patients at a Brazilian HIV and AIDS specialized service: a cross sectional study

Background:

Many human immunodeficiency virus (HIV) and syphilis co-infected patients are not diagnosed, which may evolve into asymptomatic neurosyphilis (ANS). We studied the occurrence of ANS an HIV-infected population.

Methods:

This was a cross-sectional study of cerebrospinal fluid (CSF) samples collected from patients co-infected with HIV and Treponema pallidum. Social-demographic and clinical-laboratory characteristics were studied.

Results:

Of the 348 patients infected with HIV, 33 (9.5%) had reagent treponemic and non-treponemic tests. CSF was collected from 19 asymptomatic patients. Of these, 8 (42.1%) presented with laboratory alterations suggestive of ANS.

Conclusion:

Social-demographic and clinical-laboratory variables should be considered for the indication of CSF collection.

LncRNA-ENST00000421645 promotes T cells to secrete IFN-γ by sponging PCM1 in neurosyphilis

Aim: Neurosyphilis patients exhibited significant expression of long noncoding RNA (lncRNA) in peripheral blood T lymphocytes. In this study, we further clarified the role of lncRNA-ENST00000421645 in the pathogenic mechanism of neurosyphilis. Methods: lncRNA-ENST00000421645 was transfected into Jurkat-E6-1 cells, namely lentivirus (Lv)-1645 cells. RNA pull-down assay, flow cytometry, RT-qPCR, ELISA (Neobioscience Technology Co Ltd, Shenzhen, China) and RNA immunoprecipitation chip assay were used to analyze the function of lncRNA-ENST00000421645. Results: The expression of IFN-γ in Lv-1645 cells was significantly increased compared to that in Jurkat-E6-1 cells stimulated by phorbol-12-myristate-13-acetate (PMA). Then, it was suggested that lncRNA-ENST00000421645 interacts with PCM1 protein. Silencing PCM1 significantly increased the level of IFN-γ in Lv-1645 cells stimulated by PMA. Conclusion: This study revealed that lncRNA-ENST00000421645 mediates the production of IFN-γ by sponging PCM1 protein after PMA stimulation.

Neurosyphilis

PURPOSE OF REVIEW

This article focuses on the epidemiology, clinical presentation, diagnosis, and management of neurosyphilis, with an emphasis on clinically relevant issues faced by the practicing neurologist.

RECENT FINDINGS

The incidence of primary and secondary syphilis, the sexually transmissible stages of infection, has been on the rise for the past 2 decades. A concerning recent trend is the surge in cases of syphilis in women and of congenital syphilis. Neurosyphilis remains a relatively common complication that can occur at any stage of syphilis. Along with meningitis, meningovascular syphilis, which has been historically described as a late presentation of neurosyphilis, now frequently occurs as a manifestation of early infection. Late forms of neurosyphilis, including tabes dorsalis and general paresis, are less prevalent in the era of widespread penicillin use. As more laboratories adopt the reverse-sequence algorithm for syphilis testing, patients with serodiscordant results (ie, a reactive serum treponemal test with a nonreactive nontreponemal test) may present an increasingly encountered diagnostic challenge for neurologists. Although the CSF Venereal Disease Research Laboratory (VDRL) remains a mainstay of diagnostic testing for neurosyphilis, using a higher titer cutoff (greater than 1:320) for the Treponema pallidum particle agglutination assay (TPPA) from the CSF may improve the utility of the TPPA as a supporting criterion for the diagnosis of neurosyphilis. Penicillin G is the treatment of choice for neurosyphilis, although ceftriaxone may be a reasonable alternative therapy.

SUMMARY

A high index of suspicion and awareness of the variable clinical presentations of neurosyphilis are essential to the approach to this treatable infection. Neurologists should be mindful of the limitations of serologic testing in the diagnosis of neurosyphilis and exercise clinical judgment to determine the likelihood of the diagnosis.

Sexually Transmitted Infections Treatment Guidelines, 2021

These guidelines for the treatment of persons who have or are at risk for sexually transmitted infections (STIs) were updated by CDC after consultation with professionals knowledgeable in the field of STIs who met in Atlanta, Georgia, June 11–14, 2019. The information in this report updates the 2015 guidelines. These guidelines discuss 1) updated recommendations for treatment of Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis; 2) addition of metronidazole to the recommended treatment regimen for pelvic inflammatory disease; 3) alternative treatment options for bacterial vaginosis; 4) management of Mycoplasma genitalium; 5) human papillomavirus vaccine recommendations and counseling messages; 6) expanded risk factors for syphilis testing among pregnant women; 7) one-time testing for hepatitis C infection; 8) evaluation of men who have sex with men after sexual assault; and 9) two-step testing for serologic diagnosis of genital herpes simplex virus. Physicians and other health care providers can use these guidelines to assist in prevention and treatment of STIs.

Outcomes From Re-Treatment and Cerebrospinal Fluid Analyses in Patients With Syphilis Who Had Serological Nonresponse or Lack of Seroreversion After Initial Therapy

BACKGROUND

We conducted an observational study to determine whether patients with syphilis who do not demonstrate serological cure or lack of seroreversion in nontreponemal (NT) antibody titers after initial therapy benefit from re-treatment and cerebrospinal fluid (CSF) analysis.

METHODS

We enrolled patients with syphilis from sexually transmitted disease clinics in Guangzhou, China, who had persistent NT titers after therapy. Serological nonresponse was defined as a <4-fold decline in baseline NT titers after therapy. Lack of seroreversion was defined as demonstrating a ≥4-fold NT titer decline but without seroreversion to negative, or having persistent low-level titers (i.e., 1:1-1:2) after therapy. After consent, we abstracted medical record data regarding syphilis diagnoses, initial and re-treatment regimens, and serological outcomes. Nontreponemal titers were obtained from participants at enrollment and follow-up. We evaluated CSF findings among a subgroup of participants relative to re-treatment.

RESULTS

From March 2012 to February 2016, we enrolled 135 HIV-negative patients with syphilis with persistent NT titers after initial therapy. Among 116 participants with ≥12 months of follow-up, 60 (52%) received re-treatment of syphilis. Overall, there were no significant differences in serological response between those who were re-treated and those who were not among serological nonresponders (29% vs. 27%; P = 1.0) or among participants without seroconversion (41% vs. 37%; P = 0.8). Of 60 participants who underwent CSF analyses, 8 (13%) had CSF abnormalities, but only 2 (3%) met the neurosyphilis criteria after re-treatment.

CONCLUSIONS

Most HIV-negative patients with syphilis who have serological nonresponse or lack of seroreversion after therapy do not benefit from re-treatment in the short term, and neurosyphilis is uncommon.

Ceftriaxone compared with benzylpenicillin in the treatment of neurosyphilis in France: a retrospective multicentre study

BACKGROUND

Intravenous benzylpenicillin is the gold-standard treatment for neurosyphilis, but it requires prolonged hospitalisation. Ceftriaxone is a possible alternative treatment, the effectiveness of which remains unclear. We aimed to assess the effectiveness of ceftriaxone compared with benzylpenicillin in the treatment of neurosyphilis.

METHODS

We did a retrospective multicentre study including patients with neurosyphilis who were treated at one of eight tertiary care centres in France, from Jan 1, 1997, to Dec 31, 2017. We defined neurosyphilis as positive treponemal and non-treponemal tests and at least one of otic syphilis, ocular syphilis, either neurological symptom with a positive result on cerebrospinal fluid (CSF)-VDRL or CSF-PCR tests, or more than five leukocytes in a CSF cell count. Patients with neurosyphilis were identified from the medical information department database of each centre and assigned to one of two groups on the basis of the initial treatment received (ie, benzylpenicillin group or ceftriaxone group). The primary outcome was the overall clinical response (ie, proportion of patients with a complete or partial response) 1 month after treatment initiation. The secondary endpoints were proportions of patients with a complete response at 1 month and serological response at 6 months, and length of hospital stay.

FINDINGS

Of 365 patients with a coded diagnosis of neurosyphilis in one of the eight care centres during 1997-2017, 208 were included in this study (42 in the ceftriaxone group and 166 in the benzylpenicillin group). The mean age of patients was 44·4 years (SD 13·4), and 193 (93%) were men. We observed 41 instances of overall clinical response (98%) in the ceftriaxone group versus 125 (76%) in the benzylpenicillin group (crude odds ratio [OR] 13·02 [95% CI 1·73-97·66], p=0·017). After propensity score weighting, overall clinical response rates remained different between the groups (OR 1·22 [95% CI 1·12-1·33], p<0·0001). 22 (52%) patients in the ceftriaxone group and 55 (33%) in the benzylpenicillin group had a complete response (crude OR 2·26 [95% CI 1·12-4·41], p=0·031), with no significant difference after propensity score weighting (OR 1·08 [95% CI 0·94-1·24], p=0·269). Serological response at 6 months did not differ between the groups (21 [88%] of 24 in the ceftriaxone group vs 76 [82%] of 93 in the benzylpenicillin group; crude OR 1·56 [95% CI 0·42-5·86], p=0·50), whereas hospital stay was shorter for patients in the ceftriaxone group than for those in the benzylpenicillin group (mean 13·8 days [95% CI 12·8-14·8] vs 8·9 days [5·7-12·0], p<0·0001). No major adverse effects were reported in either group.

INTERPRETATION

Our results suggest that ceftriaxone is similarly effective to benzylpenicillin for the treatment of neurosyphilis, potentially decreasing the length of hospital stay. Randomised, controlled trials should be done to confirm these results.

FUNDING

None.

Brazilian Protocol for Sexually Transmitted Infections 2020: syphilis diagnostic tests

The recommendations for diagnostic tests for investigating syphilis are part of the Clinical Protocol and Therapeutic Guidelines for Comprehensive Care for People with Sexually Transmitted Infections and the Technical Manual for Syphilis Diagnosis, published by the Brazilian Ministry of Health. These recommendations were developed based on scientific evidence and discussions with a panel of experts. This article presents direct tests to detect Treponema pallidum in lesions and algorithms that combine treponemal and non-treponemal antibody tests to assist in syphilis diagnosis, with the aim of contributing to the efforts of health service managers and health professionals in qualifying health care. The article also covers the use of non-treponemal tests to investigate neurosyphilis and guidelines for interpreting non-treponemal antibody titers in monitoring the treatment and diagnosis of congenital syphilis, as well as prospects for innovations in diagnosis. The critical role of rapid immunochromatographic treponemal tests for public health and for addressing syphilis is also highlighted.

Highlighted excerpt: During the natural evolution of syphilis, activity periods with distinct clinical, immunological, and histopathological characteristics are interspersed with latent periods when there are no signs or symptoms, making access to tests critical for early diagnosis.

Prevalence of Self-reported Neurologic and Ocular Symptoms in Early Syphilis Cases

BACKGROUND

Neurosyphilis, a complication of syphilis, can occur at any stage of infection. Measuring the prevalence of neurosyphilis is challenging, and there are limited data on the prevalence of neurologic or ocular symptoms among patients with syphilis. We sought to describe the prevalence of neurologic and/or ocular symptoms among early syphilis (ES) cases and the clinical management of symptomatic cases enrolled in the STD Surveillance Network (SSuN) Neuro/Ocular Syphilis Surveillance project.

METHODS

Persons diagnosed with ES were selected for interviews based on current health department protocols in 5 participating SSuN jurisdictions from November 2016 through October 2017. All interviewed ES cases were screened for self-reported neurologic and/or ocular symptoms. Additional clinical information on diagnostic testing and treatment for cases concerning for neurosyphilis/ocular syphilis was obtained from providers.

RESULTS

Among 9123 patients with ES who were interviewed, 151 (1.7%; 95% confidence interval [CI], 1.4%-1.9%) reported ≥ 1 neurologic or ocular symptom. Of the 53 (35%) who underwent lumbar puncture, 22 (42%) had documented abnormal cerebrospinal fluid, of which 21 (95%) were treated for neurosyphilis/ocular syphilis. Among the remaining 98 symptomatic patients with no documented lumbar puncture (65%), 12 (12%) were treated for and/or clinically diagnosed with neurosyphilis/ocular syphilis.

CONCLUSIONS

We observed a low prevalence of self-reported neurologic and/or ocular symptoms in interviewed ES cases. Approximately one-third of ES cases who self-reported symptoms underwent further recommended diagnostic evaluation. Understanding barriers to appropriate clinical evaluation is important to ensuring appropriate management of patients with possible neurologic and/or ocular manifestations of syphilis.

Molecular and Direct Detection Tests for Treponema pallidum Subspecies pallidum: A Review of the Literature, 1964-2017

Direct detection methods for Treponema pallidum include dark-field microscopy (DFM), direct fluorescence antibody (DFA) testing, immunohistochemistry (IHC), and nucleic acid amplification tests (NAATs). Here, we reviewed the relevant syphilis diagnostic literature to address 2 main questions with respect to T. pallidum direct detection techniques: “What are the performance characteristics for each direct detection test for T. pallidum and what are the optimal specimen types for each test?” and “What options are available for T. pallidum molecular epidemiology?” To answer these questions, we searched 5 electronic databases (OVID Medline, OVID Embase, CINAHL, Cochrane Library, and Scopus) from 1964 to 2017 using relevant search terms and identified 1928 articles, of which 37 met our inclusion criteria. DFM and DFA sensitivities ranged from 73% to 100% in cases of primary syphilis; and while sensitivity using silver stain histopathology for T. pallidum was generally low (0%–41%), higher performance characteristics were observed for T. pallidum–specific IHC (49–92%). Different genes have been targeted by T. pallidum–specific NAATs, with the majority of studies indicating that sensitivity is primarily dependent on the type of collected biological sample, with highest sensitivity observed in primary lesion exudate (75–95%). Given the rising incidence of syphilis, the development of direct, Food and Drug Administration–cleared T. pallidum NAATs should be considered an immediate priority.

Syphilis Laboratory Guidelines: Performance Characteristics of Nontreponemal Antibody Tests

We reviewed the relevant syphilis diagnostic literature to address the following question: what are the performance characteristics, stratified by the stage of syphilis, for nontreponemal serologic tests? The database search included key terms related to syphilis and nontreponemal tests from 1960–2017, and for data related to the venereal disease research laboratory test from 1940–1960. Based on this review, we report the sensitivity and specificity for each stage of syphilis (primary, secondary, early latent, late latent, or unknown duration; tertiary as well as neurosyphilis, ocular syphilis, and otic syphilis). We also report on reactive nontreponemal tests in conditions other than syphilis, false negatives, and automated nontreponemal tests. Overall, many studies were limited by their sample size, lack of clearly documented clinical staging, and lack of well-defined gold standards. There is a need to better define the performance characteristics of nontreponemal tests, particularly in the late stages of syphilis, with clinically well-characterized samples. Published data are needed on automated nontreponemal tests. Evidence-based guidelines are needed for optimal prozone titrations. Finally, improved criteria and diagnostics for neurosyphilis (as well as ocular and otic syphilis) are needed.

Otosyphilis: A Review of the Literature

The number of cases of syphilis has increased in the United States and in many high-income nations. Otosyphilis is a less recognized complication of syphilis that can lead to irreversible sensorineural hearing loss. Different pathophysiological mechanisms have been proposed to explain hearing loss in otosyphilis. We review the literature on otosyphilis in adults and propose the need for future work in this field to identify better ways to diagnose, treat, and manage this disease. Patients with syphilis should be screened routinely for hearing loss, and all patients with new, sudden, or fluctuating sensorineural hearing loss should be evaluated for syphilis.

Ocular and neurosyphilis: epidemiology and approach to management

PURPOSE OF REVIEW

In the context of a resurgence of syphilis worldwide, it can be anticipated that a rise in cases of ocular, otic, and neurosyphilis will also be seen. This article reviews the current epidemiology, manifestations, and approach to management and treatment.

RECENT FINDINGS

Although studies continue investigating alternate approaches and new diagnostic tests for ocular and neurosyphilis, few data exist to change current diagnostic algorithms and approaches to diagnosis, management, or follow up.

SUMMARY

The diagnosis of neurologic and eye/ear involvement with syphilis may be delayed because of a lack of specificity of findings, low suspicion for syphilis, fluctuation in symptoms, and/or similarities in presentation to other diseases. A high index of suspicion for syphilis and re-education about the protean manifestations of syphilis by all clinicians is required provide timely diagnosis and management of ocular, otic, and neurosyphilis.

[Brazilian Protocol for Sexually Transmitted Infections 2020: syphilis diagnostic tests]

The recommendations for diagnostic tests for investigating syphilis are part of the Clinical Protocol and Therapeutic Guidelines for Comprehensive Care for People with Sexually Transmitted Infections and the Technical Manual for Syphilis Diagnosis, published by the Brazilian Ministry of Health. These recommendations were developed based on scientific evidence and discussions with a panel of experts. Aiming to contribute to the efforts of health service managers and health professionals in qualifying health care, this article presents the use of direct tests to detect Treponema pallidum in lesions, as well as algorithms that combine treponemal and non-treponemal antibody tests to assist in the diagnosis of syphilis. The article also covers use of non-treponemal tests to investigate neurosyphilis and guidelines for interpreting non-treponemal antibody titers in monitoring treatment and diagnosis of congenital syphilis, as well as prospects for innovations in diagnosis. The important role of rapid immunochromatographic treponemal tests for public health and for addressing syphilis is also highlighted.

German guidelines on the diagnosis and treatment of neurosyphilis

Introduction

In view of the importance of neurosyphilis and the difficulties encountered in diagnosing it, the S1 guideline "Neurosyphilis" has been published by the German Society for Neurology (DGN) in accordance with the stipulations of the Association of the Scientific Medical Societies in Germany (AWMF). The present article is an abridged translation of that German guideline.

Main recommendations

(a) Neurosyphilis can manifest as early neurosyphilis (meningitis, meningovascular neurosyphilis or syphilitic gummas) or late neurosyphilis (tabes dorsalis, general paresis). (b) The following diagnostic criteria help to establish the presence of probable neurosyphilis (always point iv, accompanied by any two of points i to iii): (i) subacute or chronic neuro-psychiatric symptoms; (ii) increased cerebrospinal fluid (CSF) cell count or signs of blood-CSF barrier disruption; (iii) positive effect of anti-neurosyphilis antibiotic therapy on clinical course and CSF findings; (iv) positive TPHA/TPPA or FTA test in serum. (c) The diagnosis of neurosyphilis is confirmed by the subsequent detection of intrathecal production of antibodies against Treponema pallidum. (d) In neurosyphilis, treatment with intravenous penicillin or ceftriaxone for 14 days is recommended. (e) The following parameters can be used to assess a therapeutic effect: clinical findings, serum VDRL, and CSF cell count.

Conclusion

The German guideline on the diagnosis and treatment of neurosyphilis is a practical tool to support clinicians in diagnosing and treating patients with neurosyphilis. This article is an abridged translation of this guideline (Klein MW, J.; Angstwurm, K.; Esser, S.; Hahn, K.; Matschke, M.; Scheithauer, S.; Schoefer, H.; Sturzenegger, M.; Wildemann, B. Neurosyphilis, S1-Leitlinie. Deutsche Gesellschaft für Neurologie, Leitlinien für Diagnostik und Thearpie in der Neurologie 2020).

The prevalence of asymptomatic neurosyphilis among HIV-negative serofast patients in China: A meta-analysis

Introduction

Neurosyphilis can occur at any stage of syphilis. After treatment, 30%-40% of syphilis patients remained serofast. But the prevalence of asymptomatic neurosyphilis (ANS) among serofast syphilis patients remains unclear. Untimely treatment or improper management for ANS may result in neurological complications. So we perform the meta-analysis to evaluate the prevalence of ANS cases among HIV-negative serofast syphilis patients for exploring their relationship and addressing their clinical management.

Methods

We searched CNKI, Wan Fang, VIP, CBMdisc, PubMed, Embase and Medline from January 1^st 1990 to September 22^nd 2020 for both English and Chinese records. We strictly restrict the eligibility criteria. STROBE was used for reporting quality assessment. We examined forest plots and conducted both fix-effects and random-effects to estimate prevalence by R version 3.6.2/R studio 1.2.1335 statistical software packages META version 4.9–9. If appropriate, between-study heterogeneity was examined using the I² statistic and subgroup analysis.

Results

Of 77 screened records, 5 were included. The pooled prevalence of ANS among HIV-negative serofast syphilis patients was 13% (95% CI 3%-23%; I² = 93% P<0.01, 417 people). The prevalence of ANS for the verified ANS classification definition was 3% (95% CI 0%-7%; I² = 67% P = 0.08, two studies, 189 people), and 21% (95% CI 6%-36%; I² = 86% P<0.01, three studies, 228 people) for the likely ANS classification. The prevalence of ANS among the serofast syphilis patients who were followed up for one year was 29% (95% CI 22%-36%; I² = 0% P = 0.5, two studies, 167 people) and 5% (95% CI 0%-13%; I² = 79% P = 0.03, two studies, 144 people) for two years. The prevalence in the studies from different geographical subgroups was as follows: 9% (95% CI 0%-19%; I² = 82% P<0.01, three studies, 169 people) in South-central China, 6% (95% CI 1%-10%; one study, 106 people) in East China, and 30% (95% CI 23%-38%; one study, 142 people) in North China.

Conclusion

This meta-analysis showed a high estimated prevalence of ANS in HIV-negative serofast syphilis patients, the prevalence of ANS among patients diagnosed with the verified ANS case definition is much lower than that for the likely ANS classification. It may be necessary to carry out nontreponemal test, protein test and leukocyte count for cerebrospinal fluid (CSF) in treated serofast patients for better clinical management to avoid neurological complications. The case classification definition of ANS is a key factor to evaluate the prevalence. Geographical heterogeneity needs more studies to detect. In future we need better-design studies to explore relationship between ANS and serofast status.

Early symptomatic neurosyphilis and ocular syphilis: A comparative study between HIV-positive and HIV-negative patients

OBJECTIVES

Since the 2000s, there has been an increase in prevalence of neurosyphilis (NS) and ocular syphilis (OS). As data about symptomatic NS/OS is limited, this study aims to assess the characteristics of symptomatic NS/OS, according to HIV status.

METHODS

We compared the clinical and biological presentation of early symptomatic NS/OS and its outcome in HIV-positive and HIV-negative patients.

RESULTS

Ninety-six patients (93% men, 49% HIV-positive) were included from 2000 to 2016 in two centers, with 67 (69%) having OS, 15 (16%) NS, and 14 (14%) both. HIV-positive patients were younger (P=0.006) and more likely to be males having sex with males (P=0.00048) or to have a history of syphilis (P=0.01). Among 81 OS, there were 43 posterior uveitis (57%), and bilateral involvement was more common in HIV-positive patients (62% versus 38%, P=0.045). Among 29 NS there were 21 cases of cranial nerve involvement (72%), seven meningitis (24%) and 11 paresthesia (38%). Involvement of the VIII^th cranial nerve was the most common (16 cases). Treponemal tests were more commonly found positive in cerebrospinal fluid in HIV-positive patients (88% versus 76%, P=0.04). Visual acuity (VA) always improved after treatment (initial VA logMAR 0.8±0.8 versus 0.1±0.1 at 3 months), but 32% and 18% of the patients still had neurological or ocular impairment respectively six and 12 months after treatment. Non-treponemal serological reversion was observed in 43/50 patients (88%) at six months.

CONCLUSION

HIV infection has no consequence on the outcome of NS and OS. Sequelae are common, emphasizing the importance of prevention, and screening, and questioning enhanced treatment.

2020 European guideline on the management of syphilis

The 2020 edition of the European guideline on the management of syphilis is an update of the 2014 edition. Main modifications and updates include: -The ongoing epidemics of early syphilis in Europe, particularly in men who have sex with men (MSM) -The development of dual treponemal and non-treponemal point-of-care (POC) tests -The progress in non-treponemal test (NTT) automatization -The regular episodic shortage of benzathine penicillin G (BPG) in some European countries -The exclusion of azithromycin as an alternative treatment at any stage of syphilis -The pre-exposure or immediate post-exposure prophylaxis with doxycycline in populations at high risk of acquiring syphilis.

Immunization with nontreponemal antigen alters the course of experimental syphilis in the rabbit model

The role of nontreponemal antibodies in the Treponema pallidum infection course is unclear. We investigated the effect of immunization with nontreponemal antigen on T. pallidum-challenged rabbits. Nontreponemal antigen was injected intravenously into rabbits in the nontreponemal group (n = 12) to elicit antibodies (≥1:64), and normal saline-injected rabbits were used as controls (n = 12). Then, rabbits were challenged with 10⁶T. pallidum per site along their back. Lesion development was observed, and the injection sites were biopsied for mRNA analysis every week. Six rabbits from both groups were euthanized at 14 d and 28 d. The popliteal lymph nodes were extracted to assess infectivity using a rabbit infectivity test. The maximum lesion diameters were not different between the two groups (12.4 ± 0.9 mm in the nontreponemal group vs. 12.5 ± 1.0 mm in the control group, P = 0.386), but the time to maximum diameter appearance was delayed by approximately 4 d in the nontreponemal group (14.4 ± 1.6 d vs. 10.8 ± 1.9 d, P = 0.000). There were no significant differences in the proportions of lesions (58/60 (96.7%) vs. 59/60 (98.3%), P = 0.500) or ulcers (55/60 (91.7%) vs. 57/60 (95.0%), P = 0.359) between the two groups. An ulcer development delay of 5 d was observed in the nontreponemal group (19.3 ± 2.0 d vs. 14.0 ± 1.8 d, P = 0.000). IL-2 and IFN-γ mRNA expression in the nontreponemal group was significantly higher than that in the control group at 7 d and 14 d post-challenge. flaA mRNA expression and the rabbit infectivity test positive rate were not different between the two groups. Immunization with nontreponemal antigen altered the syphilis course in rabbits, resulting in delayed maximal lesion diameter and ulcer development, but it could not inhibit the spread of T. pallidum from primary lesion sites to viscera.

Cerebrospinal Fluid Cytokines in Patients with Neurosyphilis: The Significance of Interleukin-10 for the Disease

The aim of this study was to examine the cerebrospinal fluid (CSF) concentrations of proinflammatory and anti-inflammatory cytokines in neurosyphilis (NS), analyze the differences between asymptomatic NS (ANS) and symptomatic NS (SNS), and explore the diagnostic value of these cytokines. We enrolled 45 patients with a diagnosis of NS, including 18 patients with ANS and 27 patients with SNS, whose cerebrospinal fluid (CSF) samples were collected before penicillin therapy. Twelve patients with syphilis but non-NS (NNS) were also included. We measured the CSF levels of interleukin- (IL-) 1β, IL-4, IL-6, IL-10, IL-17A, IL-21, and tumor necrosis factor- (TNF-) α; the CSF levels of the microglial activation marker soluble triggering receptor expressed on myeloid cells 2 (sTREM2); and the CSF levels of the neuronal injury marker neurofilament light proteins (NFL) using the human cytokine multiplex assay or ELISA. Of the measured cytokines in the CSF, only IL-10 levels were significantly increased in NS patients compared to NNS patients (p < 0.001). In a subgroup analysis, the CSF levels of IL-10 were significantly elevated in SNS patients compared to ANS and NNS patients (p = 0.024 and p < 0.001, respectively). The CSF IL-10 levels had a significant correlation with the markers of microglial activation and neuronal injury, and they also correlated with CSF rapid plasma reagin (RPR) titer, CSF white blood cell (WBC) count, and CSF protein concentration. The areas under the ROC curve (AUC) of CSF IL-10 in the diagnosis of NS and ANS were 0.920 and 0.891, respectively. The corresponding sensitivities/specificities were 86.7%/91.7% and 83.3%/91.7%, respectively. Therefore, the excessive production of IL-10 might facilitate bacterial persistent infection, play an important role in the pathogenesis of NS, and associate with the progression of the disease. CSF IL-10 concentration had a useful value in the diagnosis of NS, especially in ANS.

More than meets the eye: Papilledema from syphilis posing as idiopathic intracranial hypertension

Idiopathic intracranial hypertension (IIH), or pseudotumor cerebri, is a diagnosis of exclusion. Elevated intracranial pressure (ICP) can result from a variety of inflammatory and structural causes affecting cerebrospinal fluid production and absorption. First described in 1935, syphilis is a well-established cause of elevated ICP, referred to as syphilitic hydrocephalus. We report a case of a 49-year-old man presenting with vision changes and headache who was treated for IIH without resolution of symptoms, and eventually diagnosed with syphilitic hydrocephalus. Syphilis should be considered as a cause of elevated ICP prior to a diagnosis of IIH.

Identification of the Neuroinvasive Pathogen Host Target, LamR, as an Endothelial Receptor for the Treponema pallidum Adhesin Tp0751

Treponema pallidum subsp. pallidum is the causative agent of syphilis, a human-specific sexually transmitted infection that causes a multistage disease with diverse clinical manifestations. Treponema pallidum undergoes rapid vascular dissemination to penetrate tissue, placental, and blood-brain barriers and gain access to distant tissue sites. The rapidity and extent of T. pallidum dissemination are well documented, but the molecular mechanisms have yet to be fully elucidated. One protein that has been shown to play a role in treponemal dissemination is Tp0751, a T. pallidum adhesin that interacts with host components found within the vasculature and mediates bacterial adherence to endothelial cells under shear flow conditions. In this study, we further explore the molecular interactions of Tp0751-mediated adhesion to the vascular endothelium. We demonstrate that recombinant Tp0751 adheres to human endothelial cells of macrovascular and microvascular origin, including a cerebral brain microvascular endothelial cell line. Adhesion assays using recombinant Tp0751 N-terminal truncations reveal that endothelial binding is localized to the lipocalin fold-containing domain of the protein. We also confirm this interaction using live T. pallidum and show that spirochete attachment to endothelial monolayers is disrupted by Tp0751-specific antiserum. Further, we identify the 67-kDa laminin receptor (LamR) as an endothelial receptor for Tp0751 using affinity chromatography, coimmunoprecipitation, and plate-based binding methodologies. Notably, LamR has been identified as a receptor for adhesion of other neurotropic invasive bacterial pathogens to brain endothelial cells, including Neisseria meningitidis, Haemophilus influenzae, and Streptococcus pneumoniae, suggesting the existence of a common mechanism for extravasation of invasive extracellular bacterial pathogens.IMPORTANCE Syphilis is a sexually transmitted infection caused by the spirochete bacterium Treponema pallidum subsp. pallidum. The continued incidence of syphilis demonstrates that screening and treatment strategies are not sufficient to curb this infectious disease, and there is currently no vaccine available. Herein we demonstrate that the T. pallidum adhesin Tp0751 interacts with endothelial cells that line the lumen of human blood vessels through the 67-kDa laminin receptor (LamR). Importantly, LamR is also a receptor for meningitis-causing neuroinvasive bacterial pathogens such as Neisseria meningitidis, Haemophilus influenzae, and Streptococcus pneumoniae Our findings enhance understanding of the Tp0751 adhesin and present the intriguing possibility that the molecular events of Tp0751-mediated treponemal dissemination may mimic the endothelial interaction strategies of other invasive pathogens.

Altered Brain Function in Young HIV Patients with Syphilis Infection: A Voxel-Wise Degree Centrality Analysis

Objective

This study assessed the possible effect of syphilis co-infection in the brain function in young HIV patients by using voxel-wise degree centrality (DC) analysis.

Methods

Forty-four syphilis-co-infected HIV patients (HIV+/syphilis+), 45 HIV patients without syphilis history (HIV+/syphilis-) and 43 matched healthy controls (HC) underwent resting-state fMRI examinations. Laboratory tests and a battery of neuropsychological tests were performed before each MRI examination. One-way ANOVA was used to compare the differences of DC among the three groups. The correlations between MRI metrics and laboratory/neuropsychological tests in each patient's group were performed by Pearson correlation analysis.

Results

Compared with HIV+/syphilis-, worse performance in complex motor skills was found in HIV+/syphilis+. Compared with HC, HIV+/syphilis+ and HIV+/syphilis- groups showed attenuated DC in the right orbital frontal cortex and increased DC in the left parietal/temporal cortex. Besides, we also found increased DC in the left inferior frontal cortex and bilateral posterior cingulated cortex/precuneus in HIV+/syphilis+ compared with HC. Moreover, compared with HIV+/syphilis-, HIV+/syphilis+ displayed decreased DC in the left middle occipital cortex. Additionally, in HIV+/syphilis+ group, the mean z value of DC was correlated to the CD4+ cell counts and the learning and delayed recall score.

Conclusion

Syphilis co-infection might be related to more brain functional reorganization in young HIV patients which could be reflected by DC value.

Successful isolation of Treponema pallidum strains from patients' cryopreserved ulcer exudate using the rabbit model

Clinical isolates of Treponema pallidum subspecies pallidum (T. pallidum) would facilitate study of prevalent strains. We describe the first successful rabbit propagation of T. pallidum from cryopreserved ulcer specimens. Fresh ulcer exudates were collected and cryopreserved with consent from syphilis-diagnosed patients (N = 8). Each of eight age-matched adult male rabbits were later inoculated with a thawed specimen, with two rabbits receiving 1.3 ml intratesticularly (IT), and six receiving 0.6 ml intravenously (IV) and IT. Monitoring of serology, blood PCR and orchitis showed that T. pallidum grew in 2/8 rabbits that were inoculated IV and IT with either a penile primary lesion specimen (CDC-SF003) or a perianal secondary lesion specimen (CDC-SF007). Rabbit CDC-SF003 was seroreactive by T. pallidum Particle Agglutination (TP-PA) and Rapid Plasma Reagin (RPR) testing, PCR+, and showed orchitis by week 6. Euthanasia was performed in week 7, with treponemal growth in the testes confirmed and quantified by qPCR and darkfield microscopy (DF). Serial passage of the extract in a second age-matched rabbit also yielded treponemes. Similarly, rabbit CDC-SF007 showed negligible orchitis, but was seroreactive and PCR+ by week 4 and euthanized in week 6 to yield T. pallidum, which was further propagated by second passage. Using the 4-component molecular typing system for syphilis, 3 propagated strains (CDC-SF003, CDC-SF007, CDC-SF008) were typed as 14d9f, 14d9g, and 14d10c, respectively. All 3 isolates including strain CDC-SF011, which was not successfully propagated, had the A2058G mutation associated with azithromycin resistance. Our results show that immediate cryopreservation of syphilitic ulcer exudate can maintain T. pallidum viability for rabbit propagation.