Xiao-Zhen Zhu

Whole genome sequence of the Treponema pallidum subsp. pallidum strain Amoy: An Asian isolate highly similar to SS14

Treponema pallidum ssp. pallidum (T. pallidum), the causative agent of the sexually transmitted disease syphilis, is an uncultivatable human pathogen. The geographical differences in T. pallidum genomes leading to differences in pathogenicity are not yet understood. Presently, twelve T. pallidum genomes are available to the public, all of which are American in origin and often co-infect patients with human immunodeficiency virus (HIV). In this study, we examined the T. pallidum subsp. pallidum strain Amoy, a syphilis pathogen found in Xiamen, China. We sequenced its genome using Illumina next-generation sequencing technology and obtained a nearly (98.83%) complete genome of approximately 1.12 Mbps. The new genome shows good synteny with its five T. pallidum sibling strains (Nichols, SS14, Mexico A, DAL-1, and Chicago), among which SS14 is the strain closest to the Amoy strain. Compared with strain SS14, the Amoy strain possesses four uncharacterized strain-specific genes and is likely missing six genes, including a gene encoding the TPR domain protein, which may partially account for the comparatively low virulence and toxicity of the Amoy strain in animal infection. Notably, we did not detect the 23S rRNA A2058G/A2059G mutation in the Amoy strain, which likely explains the sensitivity of Amoy strain to macrolides. The results of this study will lead to a better understanding of the pathogenesis of syphilis and the geographical distribution of T. pallidum genotypes.

Factors associated with syphilis infection: a comprehensive analysis based on a case-control study

This study aimed to comprehensively evaluate factors that influence the likelihood of syphilis infection from risk-taking behaviours and medical conditions. A retrospective case-control study was conducted by enrolling 664 syphilis inpatients (excluding 11 congenital syphilis patients) and 800 sex- and age-matched controls. Medical histories, clinical data and patient interview data were collected and subjected to logistic regression analyses. The prevalence of syphilis in the study population was 3·9% (675/17,304). By univariate analysis, syphilis infection was associated with migration between cities, marital status, smoking, reproductive history, hypertension, elevated blood urea nitrogen (BUN) and infection with hepatitis B virus (HBV) (P < 0·05). A high rate of syphilis-HBV co-infection was observed in HIV-negative patients and further research revealed an association between syphilis and specific HBV serological reactivity. Syphilis was also associated with the frequency, duration and status of tobacco use. Multivariate analysis indicated that syphilis infection was independently associated with migration between cities [adjusted odds ratio (aOR) 1·368, 95% confidence interval (CI) 1·048-1·785], current smoking (aOR 1·607, 95% CI 1·177-2·195), elevated BUN (aOR 1·782, 95% CI 1·188-2·673) and some serological patterns of HBV infection. To prevent the spread of infectious diseases, inpatients and blood donors should be tested for HIV, syphilis, HBV and HCV simultaneously.

Clinical and laboratory characteristics in patients suffering from general paresis in the modern era

BACKGROUND No gold standard currently exists for the diagnosis of general paresis (GP), thus often resulting in unnecessarily delayed therapeutic decision. METHODS A retrospective chart review was performed for 85 inpatients with GP in Zhongshan Hospital, Medical College of Xiamen University, and the characteristics of their clinical profiles, serum and cerebrospinal fluid (CSF) examinations, neuroimaging examination, and electroencephalogram (EEG) data were analyzed. RESULTS Among the 85 GP patients, the clinical symptoms that were frequently observed upon admission included a variety of psychiatric-behavioral symptoms and varying degrees of cognitive impairment. All of the patients had positive serum Treponema pallidum particle agglutination (TPPA) assays, 96.47% of the patients had positive CSF TPPA assays, and 41.18% of the patients had both CSF pleocytosis and elevated CSF protein levels. Focal atrophy in one cerebral region or in multiple regions was evident in neuroimages. The EEG data primarily showed slightly abnormal EEG activity. CONCLUSION These results demonstrate the complexity of the clinical characteristics of GP and highlight the importance of early diagnosis.

Origin of Nontreponemal Antibodies During Treponema pallidum Infection: Evidence From a Rabbit Model

The origin of nontreponemal antibodies during syphilis infection is hotly debated. Here, we analyzed the immune response in rabbits immunized with various antigens. Inactivated treponemes elicited the production of low-titer nontreponemal antibodies in some rabbits. Cardiolipin combined with bovine serum albumin also induced anticardiolipin antibody production. These findings indicate that Treponema pallidum contained a cardiolipin antigen with weak immunogenicity. However, active T. pallidum induced higher nontreponemal antibody production with strong immunogenicity at an earlier time point, and the antibody titer was consecutive, suggesting the high nontreponemal antibody titer resulted from the combined effects of both the T. pallidum cardiolipin antigen and the damaged host-cell cardiolipin antigen during syphilis infection, the latter of which plays a major role in the induction of nontreponemal antibody production. Our study provides direct animal evidence of the origin of nontreponemal antibodies during T. pallidum infection.

A negative nontreponemal and/or specific antitreponemal IgM test does not exclude active infectious syphilis: evidence from a rabbit infectivity test

Background: The diagnostic criteria for active infectious syphilis in the clinic are important matter of controversy and debate. So far, clinicians habitually do use the negative results of the nontreponemal and/or the specific antitreponemal IgM as the evidences of disease-free or active infection-free status. Method: We present a case study involving a patient who was admitted to Zhongshan Hospital because of cerebral infarct. Clinical examination indicated he had a history of latent syphilis with negative nontreponemal and specific antitreponemal IgM tests. The cerebrospinal fluid sample from the patient was inoculated into seronegative New Zealand rabbit. Results: Motile Treponema pallidum was detected by a rabbit infectivity test in the patients cerebrospinal fluid. This syphilis strain was confirmed by DNA subtyping form of “centers for disease control subtype/tp0548 sequence type”, and the strain type was 14d/f. Treatment with benzathine penicillin provided no apparent benefit, but treatment with aqueous crystalline penicillin G, especially recommended for neurosyphilis, led to disease regression. No evidence of cerebral infarct was observed during a 2-year follow-up period. Conclusion: The definitive differential diagnosis of active infectious syphilis should be reconsidered. Moreover, selecting the appropriate penicillin preparation is important because T pallidum can reside in sequestered sites. It is necessary to treat a patient with known invasion of the central nervous system with aqueous crystalline penicillin G, if previous treatment for syphilis failed and patients had some clinical neurological presentation that is otherwise unexplained, but that could represent neurosyphilis. Additional studies are needed to confirm the results in other syphilis patients.

Macrophage migration inhibitory factor as a novel cerebrospinal fluid marker for neurosyphilis among HIV-negative patients

BACKGROUND Neurosyphilis (NS) is difficult to diagnose, especially in syphilis patients with negative cerebrospinal fluid (CSF) rapid plasma reagin (RPR) or Venereal Disease Research Laboratory (VDRL) tests. METHODS We conducted a cross-sectional study and an analysis of macrophage migration inhibitory factor (MIF) in syphilitic patients to identify a novel marker for the diagnosis of NS, with a focus on probable NS (NS with negative VDRL/RPR tests). For this purpose, CSF and serum MIF concentrations were determined in 43 NS and 43 syphilis/non-NS (N-NS) patients at the Zhongshan Hospital of the Medical College of Xiamen University from July 2014 to June 2015. Sixty-three blood donors were used as healthy controls. RESULTS NS patients had higher CSF (median [IQR]: 8.77ng/ml [4.76-19.13]) and serum (52.58ng/ml [28.31-95.94]) MIF concentrations than N-NS patients did (4.08 [2.21-9.68] and 34.30 [19.77-59.75], respectively). Using a cut-off point of 6.63ng/ml, CSF MIF had a sensitivity of 74.42% and a specificity of 67.74% for the diagnosis of NS. The sensitivity was higher than that of CSF RPR (39.53%) and increased protein (48.84%) tests and similar to that of CSF pleocytosis (67.44%). Additionally, the sensitivity of CSF MIF, which was 92.31% for the diagnosis of probable NS, was higher than that of CSF pleocytosis (65.38%) and increased protein (53.85%) tests. By integrating all CSF parameters (pleocytosis, increased protein and MIF), the sensitivity would be improved to 100% by parallel testing, which would avoid missed diagnoses. Moreover, the specificity would be improved to 100% by the serial testing algorithm, which would again avoid misdiagnosis. CONCLUSIONS CSF MIF concentrations can be used as a novel CSF marker to establish or exclude a diagnosis of NS.

Akt, mTOR and NF-κB pathway activation in Treponema pallidum stimulates M1 macrophages

ABSTRACT The polarization of macrophages and the molecular mechanism involved during the early process of syphilis infection remain unknown. This study was conducted to explore the influence of Treponema pallidum (T. pallidum) treatment on macrophage polarization and the Akt‐mTOR‐NF&kgr;B signaling pathway mechanism involved in this process. M0 macrophages derived from the phorbol‐12‐myristate‐13‐acetate‐induced human acute monocytic leukemia cell line THP‐1 were cultured with T. pallidum. T. pallidum induced inflammatory cytokine (IL‐1&bgr; and TNF‐&agr;) expression in a dose‐ and time‐dependent manner. However IL‐10 cytokine expression decreased at the mRNA and protein levels. Additionally, the expression of the M1 surface marker iNOS was up‐regulated with incubation time, and the expression of the M2 surface marker CD206 was low (vs. PBS treated macrophages, P<0.001) and did not fluctuate over 12h. Further studies revealed that Akt‐mTOR‐NF&kgr;B pathway proteins, including p‐Akt, p‐mTOR, p‐S6, p‐p65, and p‐I&kgr;B&agr;, were significantly higher in the T. pallidum‐treated macrophages than in the PBS‐treated macrophages (P<0.05). In addition, inflammatory cytokine expression was suppressed in T. pallidum‐induced M1 macrophages pretreated with LY294002 (an Akt‐specific inhibitor) or PDTC (an NF‐&kgr;B inhibitor), while inflammatory cytokine levels increased in T. pallidum‐induced M1 macrophages pretreated with rapamycin (an mTOR inhibitor). These findings revealed that T. pallidum promotes the macrophage transition to pro‐inflammatory M1 macrophages in vitro. The present study also provides evidence that Akt, mTOR and NF‐&kgr;B pathway activation in T. pallidum stimulates M1 macrophages. This study provides novel insights into the innate immune response to T. pallidum infection. HIGHLIGHTST. pallidum induced inflammatory cytokine expression in a dose‐ and time‐dependent manner.T. pallidum promotes macrophage polarization toward the M1 phenotype.Treponema pallidum stimulates M1 macrophage activation via the Akt‐mTOR‐NF‐&kgr;B signaling pathway.

Evaluation of the Boson Chemiluminescence Immunoassay as a First-Line Screening Test in the ECDC Algorithm for Syphilis Serodiagnosis in a Population with a High Prevalence of Syphilis

ABSTRACT We developed a new Boson chemiluminescence immunoassay (CIA) and evaluated its application with cross-sectional analyses. Our results indicated that the Boson CIA demonstrated strong discriminatory power in diagnosing syphilis and that it can be used as a first-line screening test for syphilis serodiagnosis using the European Centre for Disease Prevention and Control algorithm or as a confirmatory test when combined with a patients clinical history.

A better definition of active syphilis infection

Syphilis, caused by the spirochete Treponema pallidum subsp. pallidum, is a chronic infectionwithmany diverse clinical manifestations that occur in distinct stages [1]. Because T. pallidum cannot be cultured [2], the diagnosis of syphilis is based on clinical findings, examination of lesion exudates and serologic tests. Serology is the primary method for the laboratory diagnosis of syphilis and can be divided into two groups: treponemal tests, including the T. pallidum hemagglutination test (TPHA), the T. pallidum particle agglutination assay (TPPA), the fluorescent treponemal antibody absorption test (FTA-ABS), Western blotting, and several ELISAs; and nontreponemal tests, including the Venereal Diseases Research Laboratory (VDRL) test, the rapid plasma reagin (RPR) circle card test, and the toluidine red unheated serum test (TRUST) [3]. Treponemal-specific IgM and IgG antibodies are usually generated two and fourweeks after infection, respectively [4], appearing earlier than nontreponemal antibodies. The IgM antibody may persist and does not disappear, even if the patient receives adequate treatment [5,6]. Moreover, reaginic antibodies may be negative in cases of late, latent, or post-treatment syphilis (due to seroreversion) [7]. The accuracy of diagnostic tests is critical for the successful control of epidemic syphilis outbreaks, which requires both identifying cases and promptly delivering therapy to infected individuals [8,9]. Moreover, definitive diagnosis of the infection status of syphilis is very important in clinical practice. If an active syphilis infection is not diagnosed and effectively treated, syphilis can develop into more serious diseases, such as gummatous disease and cardiovascular disease, or progress to involvement of the central nervous system [10]. Active syphilis infection is particularly dangerous in pregnant women, as syphilis has long been recognized as amajor cause of death and disability in infants born to infectedwomen. In the presence of active syphilis infection, it is estimated that adverse outcomes occur in 50–80% of pregnancies that continue past 12 weeks of gestation, primarily in the form of spontaneous abortions in the second and early third trimesters, stillbirths, and congenital syphilis [11]. Thus, establishing an accurate definition of active syphilis infection is necessary. However, no definitive reference standard has been defined for active syphilis infection. Donkers et al. [12] describe a new assay for the diagnosis of syphilis. The authors compared the SiemensADVIA Centaur® Syphilis assaywith 2 other commercial assays and evaluated its performance and usability. In this work, the authors used the VDRL test and Western blotting for IgG and IgM to define the different clinical statuses of syphilis infection, including active infection and old infection. Interestingly, the authors considered a VDRL titer of ≥1:8 to be a prognostic indicator of active syphilis infection. However, this definition of active syphilis infection should be reconsidered. Many studies have shown [11,13–17] that active syphilis infection should be defined by positive treponemal tests and any positive RPR/VDRL titer, rather than only by a VDRL

The characteristics of beta 2-glycoprotein I-dependent anticardiolipin antibody and blood coagulation status in subjects with classical biological false-positive syphilis reactions

Abstract Anticardiolipin antibody (ACA) includes beta2‐glycoprotein I‐dependent (&bgr;2‐GPI‐dependent) and &bgr;2‐GPI‐independent forms. The appearance of &bgr;2‐GPI‐dependent ACA and its association with blood coagulation have never been investigated in subjects with classical biological false‐positive syphilis reactions (CBFP). In total, 146 CBFP subjects, 465 syphilis patients and 64 presumed antiphospholipid antibody syndrome (pAPS) patients were enrolled, and &bgr;2‐GPI‐dependent ACA IgA/IgG/IgM and anti‐&bgr;2‐GPI IgA/IgG/IgM antibodies were detected via chemiluminescence assay. Conventional blood coagulation indices were measured to analyze their associations with these autoantibodies. In current study, the positive rate of &bgr;2‐GPI‐dependent ACA in CBFP subjects was 22.60%, which was significantly higher than that in syphilis patients (3.87%) (P < 0.001) and similar to that in pAPS patients (32.81%) (P = 0.119). The predominant autoantibody isotypes were IgG in CBFP subjects and pAPS patients and IgM in syphilis patients. Positive autoantibody rates were independent of rapid plasma reagin titers. CBFP and pAPS subjects had longer prothrombin times (P < 0.001) and activated partial thromboplastin times (APTTs, P < 0.001) but lower fibrinogen concentrations (P = 0.022) and platelet counts (P < 0.001) than syphilis patients. APTTs were prolonged in CBFP, syphilis and pAPS subjects with positive autoantibodies compared with those in subjects with negative autoantibodies (P < 0.05). In conclusion, ACAs in CBFP and syphilis subjects are heterogeneous; &bgr;2‐GPI‐dependent ACA constitutes a significant proportion of ACAs in CBFP subjects, while &bgr;2‐GPI‐independent ACA predominates in syphilis patients. CBFP subjects are more prone to blood coagulation disorders than syphilis patients, and these autoantibodies may impact the intrinsic coagulation cascade in CBFP subjects, similar to pAPS patients. HighlightsAnticardiolipin antibodies (ACAs) in CBFP and syphilis subjects are heterogeneous.&bgr;2‐GPI‐dependent ACA accounts for a significant proportion of ACA in CBFP subjects.No associations exist between RPR titers and positive &bgr;2‐GPI‐dependent ACA in CBFP.CBFP subjects are more prone to coagulation disorder than are syphilis patients.