Cerebrospinal fluid CXCL13 concentration for diagnosis of neurosyphilis: a systematic review and meta-analysis.

OBJECTIVE: To systematically assess the diagnostic accuracy of CXCL13 testing of cerebrospinal fluid (CSF) for neurosyphilis diagnosing. DESIGN: Systematic review and meta-analysis. DATA SOURCES: PubMed, Embase, Cochrane Library and Web of Science databases from their inception until 1 May 2023. ELIGIBILITY CRITERIA: Both cross-sectional and case-control diagnostic test studies evaluating the diagnostic value of CSF CXCL13 in diagnosing neurosyphilis were included, with no language restrictions. DATA EXTRACTION AND SYNTHESIS: Two researchers extracted data independently from all finally included articles. The updated Quality Assessment of Diagnostic Accuracy Studies tool was used to assess the quality of the included studies. Quantitative synthesis was done using a bivariate random-effects model. RESULTS: This meta-analysis included seven eligible studies involving a total of 1152 patients with syphilis and 430 patients with neurosyphilis. The pooled sensitivity, specificity and summary area under the curve (AUC) of CSF CXCL13 testing for the diagnosis of neurosyphilis were 0.76 (95% CI 0.64 to 0.85; I2=82%), 0.83 (95% CI 0.80 to 0.85; I2=32.29%) and 0.84 (95% CI 0.81 to 0.87), respectively. Sensitivity analysis confirmed the stability of the combined results. Meta-regression analysis revealed that the heterogeneity of pooled sensitivity was related to different study regions; subgroup analysis indicated that the diagnostic value of CSF CXCL13 testing reported in studies from China was superior to that reported in non-Chinese studies (pooled sensitivity, specificity and summary AUC values were 0.84 (I2=0) vs 0.64 (I2=79.53%), 0.83 (I2=42.03%) vs 0.83 (I2=32.87%) and 0.87 vs 0.83, respectively). The diagnostic value reported in studies with a sample size ≥200, unclassified neurosyphilis and HIV-negative subgroups was superior to the total combined value. CONCLUSIONS: This meta-analysis has demonstrated a reasonable level of accuracy for diagnosis of neurosyphilis with CSF CXCL13 testing. Further multicentre, prospective diagnostic studies, especially in asymptomatic neurosyphilis and HIV-infected patients, are needed to provide more evidence for evaluation before clinical application. PROSPERO REGISTRATION NUMBER: CRD42023414212.

Development and Evaluation of a Novel Antibacterial Wound Dressing: A Powder Preparation Based on Cross-Linked Pullulan with Polyhexamethylene Biguanide for Hydrogel-Transition in Advanced Wound Management and Infection Control.

As antibiotic resistance increasingly undermines traditional infection management strategies, there is a critical demand for innovative wound care solutions that address these emerging challenges. This study introduces a novel antibacterial wound dressing based on Cross-Linked Pullulan (Pul) and Polyhexamethylene Biguanide (PHMB) for enhanced wound management and infection control. The dressing's adsorption rate reached 200% of its original weight within 30 min, exceeded 300% after 5 h, and exhibited significant non-Newtonian fluid properties. The dressings were able to release the loaded medication completely within 20 min; additionally, the dressing demonstrated significant antibacterial activity against a broad spectrum of bacteria. Significantly, the therapeutic effects of the Pul-PHMB/GP dressing were evaluated in a mouse model. Compared to untreated wounds, wounds treated with Pul-PHMB/GP exhibited a significant gelation process within 5 min post-treatment and showed a significant increase in wound healing rate within 12 days. This powder preparation overcomes the limitations associated with liquid and gel dressings, notably in storage and precise application, preventing the premature expansion or dissolution often caused by PHMB in high-humidity environments. The powder form can transform into a gel upon contact with wound exudate, ensuring accurate coverage of irregular wounds, such as those from burns or pressure sores, and offers excellent chemical and physical stability in a dry state, which facilitates storage and transport. This makes the dressing particularly suitable for emergency medical care and precision therapy, significantly improving the efficiency and adaptability of wound treatment and providing robust support for clinical treatments and emergency responses.

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-1ß 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.

Dendritic Cell-Derived Exosomes Stimulated by Treponema pallidum Induce Endothelial Cell Inflammatory Response through the TLR4/MyD88/NF-κB Signaling Pathway.

Exosomes have been implicated in vascular damage in recent research. The influence of dendritic cell-derived exosomes generated by Treponema pallidum (T. pallidum) on the inflammatory process of vascular cells was examined in this study. Human umbilical vein endothelial cells (HUVECs) were cocultured with exosomes isolated from dendritic cells induced by T. pallidum. Western blot and reverse transcription-quantitative real-time polymerase chain reaction were used to assess toll-like receptor 4 (TLR4) expression and the quantity of proinflammatory cytokines. The findings showed that the expression of TLR4 was considerably upregulated, and TLR4 knockdown dramatically reduced interleukin-1ß (IL-1ß), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) production in exosome-treated HUVECs. Furthermore, TLR4 silencing reduced myeloid differentiation primary response protein 88 (MyD88) and nuclear factor kappa light chain enhancer of activated B cells (NF-κB) levels in exosome-treated HUVECs. Additionally, suppression of the activity of NF-κB with BAY11-7082, an NF-κB inhibitor, also reduced the exosome-treated inflammatory response. Our results suggested that dendritic cell-derived exosomes stimulated by T. pallidum induced endothelial cell inflammation, and the TLR4/MyD88/NF-κB signal axis was activated, significantly increasing IL-1ß, IL-6, and TNF-α expression. This may have a significant role in the vascular inflammatory response in syphilis, which would contribute to the understanding of the pathogenesis of syphilis and the host immunological response to T. pallidum.

Lysosome-Specific Coumarin-Based Fluorescent Bioprobes for in Vivo Polarity Sensing and Cancer Treatment.

About 90% of cancer deaths worldwide are caused by the spread of cancer cells from the primary tumor to distant organs (metastasis). Therefore, there is an urgent need for an early diagnosis and treatment before cancer metastasis occurs. Lysosomes have emerged as attractive targets for cancer diagnosis and treatment because polar defects in lysosomes can induce apoptosis and cell death. Coumarin is a known polar-sensitive dye with good biocompatibility; because of this, we constructed two fluorescent probes of coumarin derivatives with the "D-π-A" structure, CouN-1 and CouN-2, through three simple reactions. In molecular design, due to morpholine's prominent lysosomal targeting characteristics, it was used as both lysosomal targeting motifs and an electron donor (D), while coumarin was used as an electron acceptor (A). The experimental results strongly proved that CouN-1 and CouN-2 have a good linear relationship with the polarity change of Δf = 0.209-0.308. In addition, both in vitro and in vivo imaging results have shown that CouN-1 and CouN-2 can specifically identify and monitor tumor sites. In the cell uptake and apoptosis experiments, the two probes also showed a strong antiproliferation effect on cancer cells. All of these characteristics demonstrated the potential of these two polarity-sensitive biological probes, CouN-1 and CouN-2, in the diagnosis and treatment of cancer.

The Role of Decorin in the Adhesion Process of Treponema Pallidum Subspecies Pallidum to Human Brain Microvascular Endothelial Cells.

Objective: This study aims to investigate the role of decorin in the adhesion process of Treponema pallidum subspecies pallidum (T. pallidum) to human brain microvascular endothelial cells. Methods: The study involved an in vitro experimental design. Western blot analysis was conducted to determine the protein expression level of decorin in the cells. The cells were divided into four groups: Tp group, inactivated Tp group, LPS group, and negative control group. The adhesion of T. pallidum to the cells was analyzed using darkfield microscopy counting and quantitative polymerase chain reaction (qPCR). The cells were divided into four groups based on different preprocessing treatments: control group, decorin group, DCN-siRNA group, and DCN-siRNA+decorin group. Changes in the F-actin of the cells were explored using confocal laser scanning microscopy. The cells were divided into the Tp group, Tp+decorin group, and control group. Results: Western blot analysis showed high expression of decorin in the Tp group and LPS group. Darkfield microscopy counting revealed a significantly higher number of T. pallidum adhered to a single cell in the decorin group compared to the control group. Conversely, the number of adhered T. pallidum was significantly lower in the DCN-siRNA group compared to the control group. qPCR results indicated a considerably higher T. pallidum load in the decorin group compared to the control group. In the Tp group, T. pallidum treatment induced the reorganization of F-actin, while the distribution of F-actin in the Tp+decorin group was comparable to that of the control group. Conclusions: Decorin enhances the adhesion of T. pallidum to human brain microvascular endothelial cells, suggesting that decorin may act as one of the receptors regulating the adhesion of T. pallidum to cells. Furthermore, T. pallidum treatment triggers the rearrangement of F-actin in cells, and decorin plays a protective role in this process.

Evaluation of between-assay consistency among laboratory testing methods for neurosyphilis: a systematic review.

We conducted a systematic review to analyse the consistency of nontreponemal-specific tests of Treponema pallidum in cerebrospinal fluid. We searched the PubMed, EMBASE, Web of Science, CNKI, Wanfang and Chongqing VIP databases. The inclusion criteria were studies conducted on nontreponemal-specific tests in cerebrospinal fluid (CSF) within the same population. Exclusion criteria were studies with incomplete data or where we were unable to obtain the full text, duplicate reports, case reports and studies without sensitivity or specificity results. We used kappa value analysis and McNemar's test to analyse study consistency. We initially collected a total of 198 articles and ultimately included six articles that involved 429 patients with neurosyphilis. The performance between venereal disease research laboratory tests (VDRL) and the reactive plasma regain or toluidine red serum unheated test was similar. The kappa value for consistency between VDRL and reactive plasma regain was >0.8 in three articles, and was 0.892 for consistency between VDRL and toluidine red serum unheated test in one article. Our results suggested that CSF-reactive plasma regain or CSF-toluidine red serum unheated test may serve as alternative tests in the diagnosis of neurosyphilis with CSF-VDRL.

Plasma Exosome-Derived microRNAs Profiles in Patients with Serofast Status: A Cross-Sectional Study.

Purpose: Syphilis is a sexually transmitted bacterial infection caused by Treponema pallidum (T. pallidum), which can lead to chronic morbidity and adverse complications. In clinical practice, serofast status (SF) patients present with clinical symptoms that are very similar to those of healthy individuals or syphilis-cured patients, and often require prolonged follow-up for diagnosis. Currently, there is increasing interest in the potential of plasma exosome-derived miRNA as a biomarker for the detection of infectious diseases. In this study, we aimed to explore the diagnostic potential of miRNA in SF and its possible biological implications. Patients and Methods: Exosome-derived miRNAs were isolated from peripheral plasma samples obtained from 20 patients with secondary syphilis (SS), SF, serologically cured syphilis (SC), and healthy controls (HC), and differentially expressed miRNAs (DEmiRNAs) were identified by microarray analysis. Prediction of potential target genes, functional annotation, gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were then performed. The expression of selected miRNAs was confirmed in 37 patients by quantitative reverse transcription polymerase chain reaction (RT-qPCR). A receiver operating characteristic (ROC) analysis was performed to evaluate the diagnostic performance of these miRNAs in differentiating syphilis from HC or SC. Results: The expression profile of plasma exosome-derived miRNA was discovered in individuals with SF through microarray analysis. The targeted genes of DEmiRNAs were found to be involved in diverse biological processes according to GO and KEGG analysis, such as regulation of transcription, mitochondria, Golgi, immune system, apoptosis, Ras signaling pathway, etc. Using RT-qPCR validation, miR-1273g-3p, miR-4485-5p, miR-197-3p, and miR-1908-3p showed significant upregulation in patients with SF. These miRNAs exhibited a superior diagnostic ability, either individually or combined, to distinguish SF from SC or HC. Conclusion: The DEmiRNAs in plasma exosomes may play a role in the pathogenesis of SF and have the potential to become a noble and effective diagnostic method.

Case report: Visual acuity loss as a warning sign of ocular syphilis: A retrospective analysis of 17 cases.

Objectives: To define the clinical features of ocular syphilis and analyze the cerebrospinal fluid (CSF) of ocular syphilis patients to determine the co-occurrence of neurosyphilis. Methods: This was a retrospective study of 17 patients (23 eyes) with ocular syphilis admitted to the Fifth People's Hospital, Suzhou, China from September 2017 to December 2021. Clinical manifestations, laboratory tests, treatment, and clinical outcomes were analyzed, and a review was conducted. Results: Eight males (12 eyes) and nine females (11 eyes) were enrolled. Mean patient age was 49.06 ± 3.47 years. The total manifestation time for ocular symptoms ranged from 10 days to 6 years. The cohort was comprised of three cases of early syphilis, four cases of late syphilis, and ten cases of unknown stage. The primary complaints were decreased visual acuity in 15 cases (21 eyes), ptosis in 1 case (1 eye), and loss of light perception in 1 case (1 eye). Cases were diagnosed as chorioretinitis in 7 cases (8 eyes), optic nerve retinitis in 4 cases (6 eyes), optic neuritis in 4 cases (7 eyes), and oculomotor nerve palsy in 1 case (1 eye), syphilitic stromal keratitis in 1 case (1 eye). Serum HIV antibody was positive in one case(Nos.2). All patients had reactive serum Treponema Pallidum Particle Agglutination (TPPA) and Toluidine Red Unheated Serum Test (TRUST). All patients underwent CSF examination. CSF white blood cell count was ≥5 × 106/L in 13 cases, CSF protein was >500 mg/L in 6 cases, TPPA was reactive in 15 cases, and TRUST was reactive in 5 cases. Eleven cases were also diagnosed with neurosyphilis. Patients were treated with either penicillin G sodium or ceftriaxone sodium. At time of discharge, 12 patients reported improved visual acuity. Abnormal serum or CSF examination improved in ten patients during the 6-12 month follow-up. Conclusion: Visual acuity loss is a warning indicator of ocular syphilis. Ocular syphilis primarily manifests as posterior uveitis, involving the choroid, retina, and optic nerve, and often co-occurs with neurosyphilis. Effective treatment should be administered immediately to avoid irreversible visual impairment and other serious adverse outcomes.

Electronic communication during nonwork time and withdrawal behavior: An analysis of employee cognition-emotion-behavior framework from Chinese cultural context.

Although a large number of literatures have explored the relationship between electronic communication during nonwork time and individual perception and behavior under the Western culture background, we still have some limitations on this topic under the cultural background of collectivism, dedication and "Guanxi" in China. Different from Western organizations, Chinese employees tend to put work first and are more inclusive of handling work tasks during nonwork time. This type of communication during nonwork time can significantly affect employees' cognition, emotion and behavior. From the perspective of Job Demands-Resources theory, this study constructs a double-edged (U-shaped) model between electronic communication during nonwork time and employee withdrawal behavior. Sample data were collected from 516 employees with clear working time boundaries in China. The results indicate that electronic communication during nonwork time has a U-shaped effect on employee withdrawal behavior and an inverted U-shaped effect on employee's cognition, namely job engagement. Job engagement plays a mediating role between them. Moreover, regulatory emotional self-efficacy has a moderating effect on the relationship between electronic communication during nonwork time and job engagement. These findings not only provide theoretical and practical implications for managers and employees on how to reduce withdrawal behaviors, but also advance our understanding of electronic communication during nonwork time in Chinese cultural context.

Awareness and willingness to accept syphilis chemoprophylaxis among men who have sex with men from three cities in China: a cross-sectional study.

BACKGROUND: The awareness and willingness to use doxycycline-based syphilis chemoprophylaxis among men who have sex with men (MSM) in China remain largely unknown. METHODS: We recruited MSM online from Nanjing, Wuhan and Changsha between August and October of 2021, collected data from online survey, analyzed their data using descriptive statistics, and constructed binary logistic regression for factors associated with awareness and willingness to use chemoprophylaxis for syphilis and HIV. RESULTS: Of 725 participants (44.0% of which resided in Nanjing, 37.7% in Changsha, and 18.3% in Wuhan), a majority were under 25 years of age; 62.2% had college degrees; 11.3% were HIV positive; and 5.10% had prior syphilis infection. Only 28.83% of participants had heard of syphilis chemoprophylaxis before. Odds of knowing syphilis chemoprophylaxis were higher in those who think it is necessary to have syphilis chemoprophylaxis versus those who think it is unnecessary (P = 0.002), and were higher in those whose acquaintance had chemoprophylaxis experience before (P < 0.001). Meanwhile, those who had no previous doxycycline using history, or had positive attitude were more likely to be willing to accept syphilis chemoprophylaxis (P = 0.009, P < 0.001). Over two-thirds (67.8%) of participants preferred the PEP mode in syphilis chemoprophylaxis, and side-effects of drugs remains their most worrying aspect. CONCLUSIONS: We observed elevated interest in syphilis chemoprophylaxis in MSM in our investigational areas, indicating that the combination of HIV and syphilis chemoprophylaxis in China is promising.

Ceftriaxone compared with penicillin G for the treatment of neurosyphilis: study protocol for a multicenter randomized controlled trial.

BACKGROUND: Neurosyphilis may cause irreversible neurological sequelae. First-line treatment consists of penicillin G, with ceftriaxone being an alternative treatment in patients allergic to penicillin. The lack of clinical data comparing the efficacy of these two drugs indicated the need for comparative clinical trials to improve national treatment guidelines in China. METHODS/DESIGN: In this multicenter randomized controlled clinical trial, 290 patients newly diagnosed with neurosyphilis will be randomized 1:1 to treatment with aqueous crystalline penicillin G (ACPG) or ceftriaxone. Patients will be treated with standard regimens of ACPG or ceftriaxone according to Chinese National Guidelines and will be followed up for 12 months. All clinical parameters will be assessed at baseline and at follow-up 3, 6, 9, and 12 months later. The primary outcomes will include cerebrospinal fluid (CSF) white blood cell (WBC) count, serological efficacy, and clinical efficacy. The secondary outcomes will include CSF protein concentrations, Mini-Mental State Examination (MMSE) scores, imaging results, recurrence, and time to recovery from neurosyphilis. Adverse events will be monitored and recorded during the trial. DISCUSSION: This trial will provide clinical data to determine whether ceftriaxone is non inferior to ACPG in treating neurosyphilis and will provide evidence for the improvement of treatment guidelines. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR2100047164. Registered on 9 June 2021 and updated on 23 November 2021.

High-throughput nanopore sequencing of Treponema pallidum tandem repeat genes arp and tp0470 reveals clade-specific patterns and recapitulates global whole genome phylogeny.

Sequencing of most Treponema pallidum genomes excludes repeat regions in tp0470 and the tp0433 gene, encoding the acidic repeat protein (arp). As a first step to understanding the evolution and function of these genes and the proteins they encode, we developed a protocol to nanopore sequence tp0470 and arp genes from 212 clinical samples collected from ten countries on six continents. Both tp0470 and arp repeat structures recapitulate the whole genome phylogeny, with subclade-specific patterns emerging. The number of tp0470 repeats is on average appears to be higher in Nichols-like clade strains than in SS14-like clade strains. Consistent with previous studies, we found that 14-repeat arp sequences predominate across both major clades, but the combination and order of repeat type varies among subclades, with many arp sequence variants limited to a single subclade. Although strains that were closely related by whole genome sequencing frequently had the same arp repeat length, this was not always the case. Structural modeling of TP0470 suggested that the eight residue repeats form an extended α-helix, predicted to be periplasmic. Modeling of the ARP revealed a C-terminal sporulation-related repeat (SPOR) domain, predicted to bind denuded peptidoglycan, with repeat regions possibly incorporated into a highly charged ß-sheet. Outside of the repeats, all TP0470 and ARP amino acid sequences were identical. Together, our data, along with functional considerations, suggests that both TP0470 and ARP proteins may be involved in T. pallidum cell envelope remodeling and homeostasis, with their highly plastic repeat regions playing as-yet-undetermined roles.

Neurosyphilis in China: A Systematic Review of Cases From 2009-2021.

Considered the increased threaten of neurosyphilis in China, a review on cases reported in the literature to describe the clinical epidemiological characteristics of neurosyphilis cases, may be beneficial to the early detection and management strategies of neurosyphilis for clinicians. We searched the literature on Chinese neurosyphilis cases published from January 1, 2009 to December 31, 2021, described their clinical epidemiological characteristics and calculated the prevalence of neurosyphilis amongst other associated diseases, according to the individual study criteria. A total of 284 studies including 7,486 neurosyphilis cases were included. No meta-analysis was performed due to the heterogeneity of the data. Among 149 case reports and 93 retrospective case series studies, the main clinical manifestation of 3,507 neurosyphilis cases was cerebral parenchymal syphilis (57.3%), followed by asymptomatic neurosyphilis (16.7%), meningovascular syphilis (13.6%), meningitis syphilis (7.7%) and ocular syphilis (2.8%), etc. In addition, the initial diagnosis was incorrect in 53.2% patients, and the most frequent misdiagnoses were mental disorders (31.0%), stroke (15.9%), cognitive impairment (9.0%), etc. The positive or abnormal rates of cerebrospinal fluid non-treponemal and treponemal tests, white blood cell counts and protein concentrations were 74.2%, 96.2%, 61.5%, and 60.9%, respectively. Aqueous penicillin was the first choice for treatment in 88.3% cases, and 81.7% and 50.0% patients had response in the improvement of symptoms and serological effective in CSF, respectively. Among 26 studies on neurosyphilis patients amongst other associated diseases, the prevalence of neurosyphilis amongst central nervous system infectious diseases, syphilis-associated neurological symptoms, serofast status, coinfected with human immunodeficiency virus were 10.6%-30.1%, 23.2%-35.5%, 9.8%-56.1%, and 8.9%, respectively. In summary, the lack of early detection of neurosyphilis cases remains a clinical challenge. The high rate of misdiagnosis and high prevalence of neurosyphilis amongst associated diseases strongly remind clinicians to focus on the early detection among suspected cases. Besides, the standard treatment regimen and long-term follow-up, which complied with guideline should be provided. Further prospective studies are urgent to better delineate the clinical epidemiological characteristics of neurosyphilis in China.

Eliminating Mother-to-Child Transmission of Syphilis: Chinese Practice before and during COVID-19 Pandemics.

Mother-to-child transmission (MTCT) of syphilis remains a leading cause of stillbirth and death among neonates in many developing countries. In 2007, WHO launched the global elimination of MTCT (EMTCT) of syphilis. Given the high burden of congenital syphilis, China subsequently released the specific national EMTCT policies and programs to reduce MTCT of syphilis. The congenital syphilis incidence rate per 100 000 live births in China has markedly decreased from 69.9 in 2013 to 11.9 in 2019. However, due to the global pandemic of COVID-19, the current measures for eliminating MTCT of syphilis are great challenged. In this article, we summarize the strategies and measures for the EMTCT of syphilis in China in the past 20 years, point out that we have made remarkable achievements due to the national health policy support and strong leadership of the government. In the context of COVID-19 pandemics, strengthening emergency response to the regional outbreaks of COVID-19 and adopting safe, rapid, early and high-quality clinical care to ensure that 100% of pregnant women receive prenatal syphilis testing services, ensuring the availability of Benzathine penicillin for the treatment, and strengthening the closed-loop management of pregnant women and newborns infected with syphilis are key measures to determine the effect of MTCT of syphilis. Lessons from China may be valuable for other countries that are planning to eliminate MTCT of syphilis.

Full-length TprK of Treponema pallidum subsp. pallidum in lipid nanodiscs is a monomeric porin.

TprK is a key virulence factor of Treponema pallidum subsp. pallidum (T. pallidum) due to its ability to undergo intra-strain antigenic variation through gene conversion. This mechanism can generate millions of tprK gene and protein variants to allow immune evasion and pathogen persistence during infection. In silico structural modeling supports that TprK is an outer membrane ß-barrel with porin function and with several surface-exposed loops, seven of which corresponding to the variable regions. No definitive structural of functional data, however, exist for this protein aside from its role in immune evasion. Studies to elucidate TprK biological function as a porin, are hindered by the evidence that TprK is not abundant on T. pallidum outer membrane, and by the fragility of T. pallidum envelope. To gain insight onto TprK structure and possible function as a porin, we used an Escherichia coli - based expression system that yielded highly pure full-length TprK without any intermediate denaturation step, and proceeded to reconstitute it in detergents and lipid nanodiscs. Visualization of TprK in nanodiscs using negative staining electron microscopy supported that TprK is a monomeric porin in an artificial lipid environment mimicking T. pallidum membrane. Our work provided evidence that TprK is a possible porin transporter of T. pallidum, a biological function compatible with its structural models. These results bring us closer to a comprehensive understanding of the function of this important virulence factor in syphilis pathogenesis and T. pallidum biology.

CARE-NS, a research strategy for neurosyphilis.

Neurosyphilis is a major clinical manifestation of syphilis. In recent years, an increase in neurosyphilis cases has been reported in many countries. The overall incidence of neurosyphilis remains unknown, and there is a lack of understanding of the disease pathogenesis, which hampers clinical management, development of prevention strategies, and control. This article proposes the CARE-NS research strategy to enhance the clinical management of neurosyphilis, which consists of six key features: comprehensive management including multidisciplinary treatment (C), alleviating neurological impairment and sequelae (A), risk factors and clinical epidemiology (R), etiology and pathogenesis (E), new diagnostic indicators and strategies (N), and social impact and cost-effectiveness analysis (S).

Treponema pallidum genome sequencing from six continents reveals variability in vaccine candidate genes and dominance of Nichols clade strains in Madagascar.

In spite of its immutable susceptibility to penicillin, Treponema pallidum (T. pallidum) subsp. pallidum continues to cause millions of cases of syphilis each year worldwide, resulting in significant morbidity and mortality and underscoring the urgency of developing an effective vaccine to curtail the spread of the infection. Several technical challenges, including absence of an in vitro culture system until very recently, have hampered efforts to catalog the diversity of strains collected worldwide. Here, we provide near-complete genomes from 196 T. pallidum strains-including 191 T. pallidum subsp. pallidum-sequenced directly from patient samples collected from 8 countries and 6 continents. Maximum likelihood phylogeny revealed that samples from most sites were predominantly SS14 clade. However, 99% (84/85) of the samples from Madagascar formed two of the five distinct Nichols subclades. Although recombination was uncommon in the evolution of modern circulating strains, we found multiple putative recombination events between T. pallidum subsp. pallidum and subsp. endemicum, shaping the genomes of several subclades. Temporal analysis dated the most recent common ancestor of Nichols and SS14 clades to 1717 (95% HPD: 1543-1869), in agreement with other recent studies. Rates of SNP accumulation varied significantly among subclades, particularly among different Nichols subclades, and was associated in the Nichols A subclade with a C394F substitution in TP0380, a ERCC3-like DNA repair helicase. Our data highlight the role played by variation in genes encoding putative surface-exposed outer membrane proteins in defining separate lineages, and provide a critical resource for the design of broadly protective syphilis vaccines targeting surface antigens.

The challenge of diagnosis and treatment of neurosyphilis in China: results from a nationwide survey.

Background The uncertainty of how neurosyphilis is diagnosed and treated in clinical settings led us to investigate whether this serious manifestation of syphilis infection is properly managed in China. METHODS: This national cross-sectional study of the diagnosis and treatment of neurosyphilis included 1392 clinicians at 398 hospitals located in 116 cities in China. RESULTS: Of 398 hospitals, 244 (61.3%) failed to perform diagnostic laboratory tests and 181 (45.5%) failed to provide recommended treatment for neurosyphilis. Of 1392 clinicians, 536 (38.5%) had previously diagnosed patients with neurosyphilis, but 419 (78.2%) of the latter provided diagnoses that did not meet the criteria set by national guidelines. Of the 485 clinicians who had previously treated patients with neurosyphilis, 280 (57.7%) failed to follow national guidelines for treatment. Analysis indicated that clinicians working in North China (adjusted odds ratio (aOR), 4.24; 95% confidence interval (CI), 1.65-10.88), tertiary hospitals (aOR, 3.23; 95% CI, 1.63-6.41), and hospitals specialising in sexually transmitted infections (aOR, 2.49; 95% CI, 1.24-4.99) were more likely to follow national guidelines for neurosyphilis treatment. CONCLUSION: Lack of knowledge in disease management poses a great obstacle to prevent the serious consequences of neurosyphilis in Chinese patients. More effective measures are urgently needed to improve this suboptimal situation.

A Novel tp0548 Gene Type of Treponema pallidum Identified in Nanjing, China: Case Report and Review of Literature.

BACKGROUND: The tp0548 gene, hypothesized to encode for an outer-membrane protein, was originally used in the enhanced Centers for Disease Control and Prevention typing for molecular typing of Treponema pallidum. It plays an important role in the molecular epidemiology of Treponema because it is not only an important locus of multiple typing approaches but also suitable for strain typing of multiple Treponema subspecies. METHODS: A 27-year-old Chinese man attended the Institute of Dermatology, Chinese Academy of Medical Sciences Sexually Transmitted Disease Clinic in Nanjing, China, because of a genital ulcer and inguinal lymphadenopathy for 1 week. Workup consisted of microbiological and hematological investigations, and sequences analysis. The aims of this study were to describe a novel tp0548 sequence type "Qn" of this syphilis strain and to review all previously reported novel tp0548 genotypes. RESULTS: We identified a novel tp0548 gene type in a genital ulcer in a patient with primary syphilis in Nanjing, China. Using sequence alignment, we further found that this novel sequence was closely similar to "Q." Following the nomenclature used in the enhanced Centers for Disease Control and Prevention typing methodology, the letters "Qn" was assigned to the new sequence type. CONCLUSION: The novel tp0548 sequence type of T. pallidum not only expands the database up to 27 different sequence types but also indicates the substantial genetic diversity of the tp0548 gene sequence.