Treponema Pallidum Research Articles

Multiplex Detection of Viral DNAs in Blood by Colorimetrically Identifying Polymerase Chain Reaction Amplicons with Serial Invasive Reaction Assisted Gold Nanoparticle Probes Assembling.

Detection of blood-borne pathogenic viruses is essential for blood transfusion, and has great significance for epidemiology, as well as clinical practices. Common blood-borne viruses causing infectious diseases include Hepatitis B virus (HBV), Hepatitis C virus (HCV), Human immunodeficiency virus (HIV) and Treponema pallidum (TP). Therefore, multiplex detection of these viruses is more in the line with the needs of clinical testing. Although real-time PCR-based multiplex nucleic acid testing (NAT) was developed for pathogen detection, however, the requirement of multichannel realtime PCR machine increases the instrumental cost and is not suitable for use in resource-limited areas. In this study, we proposed a multiplex and colorimetric assay for detecting viral nucleic acids in blood by using serial invasive reaction assisted gold nanoparticle (AuNPs) probes assembling to identify multiplex PCR amplicons. As low as 2 copies per reaction of HIV and TP targets, and 20 copies per reaction of HBV and HCV targets can be detected. The results can be observed by naked eyes; thus, just a standard PCR machine is required. In addition, the hairpin probe and the AuNPs for signal read out are universal for all the targets, reducing the detection cost. About 20 DNA samples remaining after clinical HBV testing were successfully detected, and the results were consistent with that of commercially available real-time PCR based kit, indicating that this method has a potential for clinical applications.

Choriocapillaris Involvement in Acute Syphilis Posterior Placoid Chorioretinitis is Responsible for Functional Impairment and Points towards an Immunologic Mechanism: A Comprehensive Clinicopathological Approach.

Purpose:To evaluate the multimodal imaging of acute syphilitic posterior placoid chorioretinitis (ASPPC) lesions in order to elucidate their pathophysiology which seems to resemble choriocapillaritis as in primary inflammatory choriocapillaropathies such as multifocal choroiditis (MFC) and acute posterior multifocal placoid pigment epitheliopathy (APMPPE).Methods:Charts of patients with ASPPC seen in the Centre for Ophthalmic Specialised Care, Lausanne, Switzerland, were retrieved. Fundus autofluorescence (FAF), spectral domain optical coherence tomography (SD-OCT), fluorescein angiography (FA), indocyanine green angiography (ICGA), and when available, OCT angiography were analyzed and compared to a case of MFC.Results:One woman aged 58 and 2 men aged 50 and 31 with unilateral ASPPC were analyzed. All had positive syphilis serologies (venereal disease research laboratory [VDRL] and treponema Pallidum hemagglutination assay [TPHA]). Two were human immunodeficiency virus (HIV) positive. Mean best corrected visual acuity was 0.2 ± 0.1 at presentation and 1.0 for all patients 6 weeks later, after antibiotic treatment for neurosyphilis. All had central scotomata with a mean defect (MD) of 12.2 ± 2.6. Six weeks later, MD values were 3.9 ± 1.7. Microperimetry had a mean score of 25/560 at presentation and recovered to a mean of 444/560 6 weeks later. Multimodal imaging features consisted of FA tissue staining, ICGA hypofluorescent choriocapillaris non-perfusion, FAF hyperautofluorescence, and loss of the ellipsoid line in the diseased areas. The findings were consistent and identical in ASPPC and a case of MFC and pointed toward the involvement of the choriocapillaris.Conclusions:Similarities seen in multimodal imaging features in ASPPC and choriocapillaritis highlight the role of the choriocapillaris in the pathophysiologic mechanism of both conditions. Inflammatory choriocapillaris non-perfusion triggered by infectious agents seems to be the common pathway through which the eye is reacting.

Sífilis: uma revisão da literatura

A intensificação do número de registros de sífilis congênita vem preocupando a saúde pública. Dados da Organização Mundial da Saúde (OMS) estimam que, em 2016 ocorreram 20 milhões de casos de sífilis em adolescentes e adultos, sendo 6,3 milhões de casos novos. No Brasil, em 2017, eram 59,1 casos por 100.00 habitantes e em 2018 75,8/100.000 habitantes. Em crianças é transmitida verticalmente pela mãe que possui a bactéria Treponema pallidum. Sendo assim, a redução do número de casos de gestantes com sífilis congênita é essencial para que os recém-nascidos não apresentem também essa patologia e suas consequências. Além disso, vale ressaltar as gestantes adolescentes que apresentam mais fatores de risco em relação à sífilis, como a rebeldia da puberdade e a falta de informação sobre o sexo seguro e, por isso, merecem uma atenção especial. O presente estudo tem como objetivo revisar a literatura a respeito do crescimento de casos de sífilis, levando em conta o aumento de gestantes com sífilis e as consequências sofridas pelo recém-nascido.

ORAL SYPHILIS: CLINICAL, HISTOPATHOLOGIC, AND IMMUNOHISTOCHEMICAL ASPECTS

Syphilis is a sexually transmitted infection, caused by the spirochete bacteria Treponema pallidum (TP), for which humans are the only reservoir. There are several clinical manifestations of syphilis, depending on the stage of disease (primary, secondary, latent, and tertiary). The congenital syphilis is a consequence of infection of the fetus, via the placenta. We report a case of secondary syphilis diagnosed with an oral lesion biopsy. A 26-year immunocompetent man was referred with an asymptomatic, single reddish ulceration in the palate. The histopathologic analysis of tissue specimen obtained by biopsy showed an epithelium with pseudoepitheliomatous hyperplasia, ulceration, acanthosis, and exocytosis, with a chronic inflammatory infiltrate of plasma cells in the connective tissue. Immunohistochemical reactions for the spirochete bacteria using anti-TP antibody were positive. The diagnosis of syphilis was confirmed by venereal disease research laboratory and fluorescent treponemal antibody absorption complementary tests, and the patient was treated with penicillin, without recurrence after 2 years’ of follow-up.

Improving the coverage and accuracy of syphilis testing: The development of a novel rapid, point-of-care test for confirmatory testing of active syphilis infection and its early evaluation in China and South Africa.

BackgroundCurrent point-of-care tests (POCT) for syphilis, based on the detection of Treponema pallidum (TP) total antibodies, have limited capacity in distinguishing between active and past/treated syphilis. We report the development and early evaluation of a new prototype POCT based on the detection of TP-IgA antibodies, a novel biomarker for active syphilis.MethodsThe TP-IgA POCT (index test) was developed in response to the World Health Organisation (WHO) target product profile (TPP) for a POCT for confirmatory syphilis testing. Two sub-studies were conducted consecutively using 458 pre-characterised stored plasma samples in China (sub-study one, addressing the criteria for the WHO TPP), and 503 venous blood samples collected from pregnant/postpartum women in South Africa (sub-study two, addressing potential clinical utility). Performance of the index test was assessed against standard laboratory-based serology using a combination of treponemal (TPHA) and non-treponemal (rapid plasma reagin [RPR]) tests.FindingsIn sub-study one, the index test demonstrated 96·1% (95%CI=91·7%-98·5%) sensitivity and 84·7% (95%CI=80·15–88·6%) specificity for identification of active syphilis (TPHA positive, RPR positive). It correctly identified 71% (107/150) samples of past-treated syphilis (TPHA positive, RPR negative). In sub-study two, the index test achieved 100% (95%CI=59%-100%) sensitivity for active syphilis and correctly identified all nine women with past syphilis.InterpretationThe TP-IgA POCT has met the WHO TPP for a POCT for diagnosis of active syphilis and demonstrated its potential utility in a clinical setting. Future studies are warranted to evaluate field performance of the final manufactured test.FundingSaving Lives at Birth: Grand Challenge for Development, Thrasher Research Fund, and the Victorian Government Operational Infrastructure Scheme.

Cost of Blood and Body Fluid Occupational Exposure Management in Beijing, China.

(1) Objective: The aim of this study was to determine the cost of blood and body fluid (BBF) occupational exposure management in healthcare facilities in Beijing, China. (2) Methods: A survey was conducted from August to October 2018, seeking general information concerning the management of occupational exposure to BBF and the cost of the management process. In total, 216 healthcare facilities were surveyed, using a stratified-selection method. The collected information included BBF management protocols, direct costs such as laboratory testing fees, drug costs and medical service fees, as well as indirect costs, such as wages, lost working time, injury compensation, and psychological counseling time. (3) Results: The cost of post-BBF exposure management varied according to the infection status of the exposure source patients, the immune status of exposed employees, and the location and level of healthcare facilities. The mean values of management cost were determined to be hepatitis B (HBV)-positive source (RMB 5936/USD 897), hepatitis C (HCV)-positive source (RMB 5738/USD 867), Treponema pallidum (TP)-positive source (RMB 4508/USD 681), human immunodeficiency virus (HIV)-positive source (RMB 12,709/USD 1920), and unknown sources (RMB 7441/USD 1124). The survey also revealed that some healthcare facilities have insufficient post-exposure management. (4) Conclusions: A better post-exposure management system is needed in Beijing to reduce both infection risk after exposure and costs.

An efficient method for simultaneously screening for HIV, syphilis, and HCV based on one dried blood spot sample

ObjectiveThe aim of this study was to optimize the parameters of a dried blood spot (DBS)-based ELISA method to simultaneously screen for anti-HIV, anti-hepatitis C virus (HCV) and anti-treponema pallidum (TP) antibodies, and investigate the assay performance. MethodsExperiments were performed to establish optimized parameters for a DBS-based ELISA method to simultaneously screen for anti-HIV, anti-HCV, and anti-TP antibodies. Then, 429 paired plasma and DBS samples were collected to evaluate the performance of the assay with optimized parameters. Plasma test results were used as the reference standard. ResultsThe optimized assay conditions were: blood volume, 70–100 μL; DBS size, whole spot; eluent volume, 500 μL; eluent, PBS with 1‰ Tween20; elution time, 4 h; elution temperature, room temperature. The overall prevalence of HIV, HCV, and TP was 6.06% (95% confidence interval [CI]: 4.07–8.87%), 27.74% (95% CI: 23.60–32.28%), and 14.92% (95% CI: 11.75–18.73%). The clinical sensitivity of the assay for anti-HIV, anti-HCV, and anti-TP antibodies was 88.46%, 98.32%, and 92.19%, respectively. The assay was 100% specificity for each analyte. The assay positive predictive value for each analyte was 100%, and the negative predictive values were >98%. Of the 429 samples, 9 DBS results were different than the plasma results; in these samples the plasma signal-to-cutoff rations were low (range, 1.40–7.81). ConclusionThe DBS-based ELISA method demonstrated good performance for simultaneously screening for anti-HIV, anti-HCV, and anti-TP antibodies. DBS samples are a promising method to screen for HIV, HCV, and TP infections. ImportanceDBS samples are a promising alternative to plasma samples, with the advantages of good sample stability, smaller blood volume, simpler storage, and easier transport. DBS sample testing is used for the diagnosis of a wide variety of pathogens, including HIV, hepatitis B virus (HBV), and hepatitis C virus (HCV). The performance of DBS samples for the serological diagnosis of HIV, HCV, and Treponema pallidum (TP) has been demonstrated to be good in many studies, and therefore DBS is regarded as an ideal choice to screen for HIV, HCV, and TP infections, especially in difficult-access or resource-limited settings. There is no generally accepted procedure for sample collection and processing of DBS samples and there are few studies on simultaneous detection of anti-HIV, anti-HCV and anti-TP using a single DBS.

Resurgence of yaws in Benin: Four confirmed cases in the district of Z, Southern Benin

Yaws is an infectious neglected tropical disease (NTD) caused by the Treponema pallidum pertenue which is highly contagious and transmitted through direct contact with an infected person. It mainly affects skin, bone and cartilage and predominantly in children under 15 years of age. The last cases in Benin were documented in 1982 in the districts of Adjohoun, Bonou and Dangbo in Southern Benin. In line with the global strategy of yaws eradication, yaws surveillance had been reactivated in Benin in 2012 through the National Control Programme of Leprosy and Buruli Ulcer (PNLLUB). Following two yaws prevalence surveys among schoolchildren in 2012 and 2013 in Southern Benin, that failed to detect yaws case, the PNLLUB adopted in 2016 field mass medical consultation campaign as an integrated screen and case management strategy for skin NTDs. During the field mass medical consultation organized in five districts in Southern Benin within October – December 2018, four yaws cases had been confirmed in two villages in the district of Ze. These are the first yaws cases confirmed in Benin since 1982 and thus confirm the re-emergence of yaws in Benin. Key words: Yaws, reemerging infectious diseases, Benin.

Evaluation of ELISA and CLIA for Treponema pallidum specific antibody detection in China: A multicenter study

BackgroundConsidering the rapid increase of syphilis infections in several countries including China, searching for a screening test with sufficient sensitivity and specificity is extremely urgent. The current study mainly researched the performance for Treponema pallidum (TP) detection by electro-chemiluminescence immunoassays (ECLIA), chemiluminescence immunoassays (CLIA) and four commercially available ELISA assays commonly used in China. Methods1372 plasma samples collected from blood centers/banks were tested with 6 assays in 8 laboratories with the Western blot (WB) or TP particle agglutination assay (TPPA) as confirmatory tests. ResultsWith the WB or TPPA as confirmatory test, the ECLIA demonstrated the highest specificity (95.2%) and Kappa coefficient (0.915), but lowest sensitivity (97.2%) compared with the other 5 assays. While the Wantai-ELISA showed the highest sensitivity (99.6%) among the 6 assays. Sensitivities were found to be significantly increased when any two of the six assays were combined for TP detection. Our study demonstrated that the Wantai-ELISA combined with the ECLIA or the KHB-ELISA or the InTec-ELISA would increase the sensitivities up to 100%. Further analysis showed that the specificities and positive predictive values were both 100.0% when cut-off of S/CO values were served as 15.42 for the ECLIA and 7.14 for the CLIA, indicating that samples under these conditions can be directly considered as positive without confirmation. ConclusionsThe CLIA and the ECLIA are more specific than ELISA to detect TP antibodies. However, ELISA is a sensitive method, especially in combination with the CLIA or the ECLIA or another types of ELISA, suitable for the routine screening of blood donations in China.

Strain diversity of Treponema pallidum subsp. pertenue suggests rare interspecies transmission in African nonhuman primates

In our most recent study, we found that in Tanzania infection with Treponema pallidum (TP) subsp. pertenue (TPE) is present in four different monkey species. In order to gain information on the diversity and epidemiological spread of the infection in Tanzanian nonhuman primates (NHP), we identified two suitable candidate genes for multi-locus sequence typing (MLST). We demonstrate the functionality of the MLST system in invasively and non-invasively collected samples. While we were not able to demonstrate frequent interspecies transmission of TPE in Tanzanian monkeys, our results show a clustering of TPE strains according to geography and not host species, which is suggestive for rare transmission events between different NHP species. In addition to the geographic stability, we describe the relative temporal stability of the strains infecting NHPs and identified multi-strain infection. Differences between TPE strains of NHP and human origin are highlighted. Our results show that antibiotic resistance does not occur in Tanzanian TPE strains of NHP origin.

Relationship between the high frequency of 23S rRNA point mutations in Treponema pallidum and low serological response rate to azithromycin treatment in China

Objective Although azithromycin is effective against Treponema pallidum (T. pallidum), the causative agent of syphilis, recent reports indicate that the prevalence of azithromycin resistance in China is very high, which may result in the failure of treatment. In this study, we aimed to investigate the association between azithromycin resistance and therapeutic outcomes in early syphilis patients. Methods Between February 2010 and December 2014, patients aged 18-65 years with early syphilis were enrolled. T. pallidum DNA were extracted to test the presence of A2058G and A2059G mutations. Then, eligible patients were randomly assigned to receive oral azithromycin (0.5 g, once daily for 15 days) or intramuscular BPG (2.4 million units, once weekly for 3 weeks). All patients were followed up in 2 weeks and 3, 6, 9, and 12 months after treatment to collect demographic and clinical characteristics and laboratory results. The differences on serological response, serological failure and serofast rate were compared between the two groups by Chi-square test. Results Among the 187 T. pallidum-infected patients enrolled, 172 (92.0%) cases had a mutation associated with azithromycin resistance (A2058G, 153 cases; A2059G, 19 cases). During the 5-year study period, the percentage of cases enrolled with these mutations steadily increased, from 90.9% in 2010 to 95.3% in 2014. Of the 172 patients presenting with these mutations, only 78 (45.3%; all benzathine penicillin G [BPG]-treated) obtained a serological response to treatment; 32.6% and 22.1% of patients presented with serological failure and serofast results, respectively. For azithromycin-treated cases, 66.3% and 33.7% had serological failure and serofast results, respectively, in contrast with 1.1% and 11.3% of BPG-treated cases. However, among the A2058G-and A2059G-negative patients, the serological response rates between the two treatment groups were similar. In multivariate analyses, patients with lower rapid plasma reagin (RPR) titers (RPR, ≤ 1:8; odds ratio[OR], 0.23; 95% confidence interval [CI], 0.09-0.37) or who received azithromycin treatment (OR, 121.50; 95% CI, 35.38-386.17) were more likely to display serological failure and serofast results. Conclusion This prospective study found that the 23S rRNA A2058G and A2059G point mutations in T. pallidum are currently circulating with high frequency in China, suggesting a correlation between the high prevalence of macrolide resistance and a lower serolo gical response rate to azithromycin treatment. Key words: Syphilis; Azithromycin; Mutation; Serological response; Treponema pallidum

Sexually transmitted infections, the silent partner in HIV-infected women in Zimbabwe.

BackgroundCoinfection rates of HIV and sexually transmitted infections (STIs) are not widely reported in Zimbabwe and no local guidelines regarding the screening of STIs in people living with HIV exist.ObjectivesThis cross-sectional study was conducted to determine the prevalence and associated risk factors for STI coinfection in a cohort of HIV-infected women.MethodsBetween January and June 2016, 385 HIV-infected women presenting for routine cervical cancer screening were tested for five STIs: Neisseria gonorrhoeae (NG), Chlamydia trachomatis (CT), Trichomonas vaginalis (TV), Herpes Simplex Virus (HSV) type 2 and Treponema pallidum (TP). Socio-demographic characteristics and sexual history were recorded. Multiple logistic regression was used to identify factors associated with the diagnosis of non-viral STIs.ResultsTwo hundred and thirty-three participants (60.5%) had a confirmed positive result for at least one STI: HSV 2 prevalence 52.5%, TV 8.1%, CT 2.1%, NG 1.8% and TP 11.4%. Eighty-seven per cent of the women were asymptomatic for any STI; 62.3% of women with a non-viral STI were asymptomatic. Women who had attended tertiary education were 90% less likely to have a non-viral STI (adjusted odds ratio [aOR]: 0.10, 95% confidence interval [CI]: 0.03–0.39, p < 0.01). Having more than three lifetime sexual partners was a significant predictor for a non-viral STI diagnosis (aOR: 3.3, 95% CI: 1.5–7.2, p < 0.01).ConclusionA high prevalence of predominantly asymptomatic STIs is reported in a cohort of HIV-infected women. Syndromic management results in underdiagnosis of asymptomatic patients. More than three lifetime sexual partners and less formal education are risk factors for coinfection with non-viral STI. High-risk women should be screened using aetiological methods.

Molecular Detection of Pathogens Causing Sexually Transmissible Infections in Patients with Prostate Cancer and Hyperplasia by Quantitative TaqMan Real-Time PCR Assay.

Prostate cancer is considered the most prevalent cancer among men. Recent studies suggest that sex-ually transmissible infections (STIs) may be related to prostate carcinogenesis. Therefore, the aim of this study was to investigate whether STI pathogens (Atopobium vaginae (ATO), Neisseria gonorrhoeae (NG), Chlamydia tra-chomatis (CT), Treponema pallidum (TP), Ureaplasma urealyticum (UU), Gardnerella vaginalis (GV), Herpes Sim-plex Virus (HSV), Cytomegalovirus (CMV), Human herpesvirus (HHV), Human papillomavirus (HPV), and Tricho-monas vaginalis (TV)) presence in prostate tissues are associated with the risk of prostate cancer. Paraffin-embedded prostate tissues obtained from patients with hyperplasia and prostate cancer were extracted. Determination of infectious microorganisms of interest was done by quantitative TaqMan real-time PCR assay. STI DNA was detected in 53/243 (21.8%) of the prostate tissues samples (ATO 3.7%, UU 2.88%, GV 2.46%, HSV-2 2.05%, CT 2.05%, CMV 1.64%, NG 1.64%, TP 1.64%, HHV-8 1.23%, HPV 1.23%, and TV 1.23%.) The statistical analysis revealed significant correlation between prevalence of Gardnerella vaginalis (GV) and Herpes Simplex Virus (HSV-2) between hyperplasia and cancerous groups (p = 0.02), respectively. No statistically significant difference was observed in the prevalence of most candidate infectious or-ganisms between hyperplasia and cancerous groups except for GV and HSV-2. It appears that inflammation in the prostate gland is more associated with prostate hyperplasia than prostate cancer. According to the role of in-fectious microorganisms in induction of chronic inflammation, we cannot exclude the importance of these patho-gens in progression of cancer. More studies are required to explore the associations of cancer with different infec-tious organisms.

Transfusion Transmissible Infections: Maximizing Donor Surveillance.

IntroductionThe World Health Organization (WHO) recommends that all blood transfusion services must screen donated blood for human immunodeficiency virus (HIV) one and two, hepatitis B, hepatitis C and syphilis. A mandatory screening for malaria is also warranted in malaria endemic areas. Our study aimed at analyzing the prevalence and different diagnostic methods of screening transfusion transmitted infections (TTIs) in replacement and voluntary, non-remunerated donors in the blood bank of a tertiary care hospital in Islamabad, Pakistan.MethodsThe cross-sectional, descriptive study was conducted on 30,470 blood donors from July 2015 to October 2017, in the blood bank of a 500-bed teaching hospital in Islamabad. Initially all blood donors were screened for HIV one, HIV two, hepatitis B and hepatitis C by serological testing. The seronegative samples were further tested by nucleic acid amplification test (NAT). Malaria was screened using immuno-chromatographic antigen-detection tests, while treponema pallidum was screened by electrochemiluminescence immunoassay to detect treponema pallidum (TP) antibodies. All infected blood and blood products were discarded and donors were contacted. The donors were deferred from blood donation according to WHO guidelines. They were also counselled and referred to the infectious diseases clinic. The collected data was analyzed on IBM's statistical package for the social sciences (SPSS) version 21.ResultsThe results revealed that amongst the 30,470 donors, 997 (3.27%) donors were found infected with one or more TTI while 29,473 (96.73%) donors were found safe. Individuals who tested positive on serology for hepatitis B were 322 (1.06%), hepatitis C were 392 (1.29%) and HIV were 49 (0.16%). The seronegative donors were tested by NAT. NAT on seronegative samples showed that 10 (0.03%) donors tested positive for hepatitis B virus deoxyribonucleic acid, while only three (0.01%) were positive for hepatitis C ribonucleic acid. No donor was found positive for HIV by NAT testing. Syphilis testing revealed a frequency of 228 (0.75%) positive results while only five (0.02%) donors were found infected with malaria.ConclusionThe results testify that standardized blood component screening can save transmission of infections through blood transfusion. They also establish the superiority of NAT screening over serological tests in decreasing the residual risk of transfusion transmitted infections.

Analysis of the results of Treponema Pallidum DNA in serum and vaginal fluid of patients with latent syphilis before and after treatment

Objective To investigate the infectivity of serum and vaginal fluid in early cases and late latent cases of syphilis. Methods From January 2015 to December 2015, sixty-eight female patients with latent syphilis were enrolled in the outpatient clinic of Ningbo Women and Children′s Hospital, including 38 early cases and 30 late cases. Tolulized red unheated serum test (TRUST) was detected by using kits and Treponema Pallidum DNA (TP-DNA) was detected by polymerase chain reaction. TP-DNA levels in serum and vaginal fluid were compared before and after benzathine penicillin treatment in patients with early and late latent syphilis. Chi square test was performed for count data analysis. Results TRUST negative conversion cases in early latent syphilis after 3, 6 and 12 months of treatment were 11 (28.9%), 16 (42.1%) and 27 (71.0%), respectively. TRUST negative conversion cases in late latent syphilis after 3, 6 and 12 months of treatment were 6 (20.0%), 12 (40.0%) and 14 (46.7%), respectively. There were no statistical differences in TRUST negative conversion rates after 3 months and 6 months after treatment between early cases and late cases (χ2=0.716 and 0.031, respectively, both P>0.05), while those after 12 months of treatment between early cases and late cases were statistical different (χ2=4.164, P 0.05). The serum TP-DNA positive cases in early syphilis before and after 3, 6, and 12 months of treatment were 18 (47.3%), 4 (10.5%), 5 (13.2%) and 5 (13.2%), respectively, with statistical difference (χ2=21.217, P 0.05). The serum TP-DNA positive cases in late syphilis before and after 3, 6, and 12 months of treatment were 8 (26.7%), 1 (3.3%), 1 (3.3%) and 1 (3.3%), respectively, with statistical difference (χ2=14.712, P<0.05). Conclusions Standard treatment can reduce the level of TP in serum and vaginal fluid of latent syphilis women and improve the negative conversion rate of TRUST. Late latent syphilis is easier to create sero-resistance than early cases. The early cases have stronger infectivity than late cases before standard treatment. Key words: Syphilis, latent; DNA; Treponema pallidum

Structure modeling to function prediction of Uncharacterized Human Protein C15orf41.

The dyserythropoietic anemia disease is a genetic disorder of erythropoiesis characterized by morphological abnormalities of erythroblasts. This is caused by human gene C15orf41 mutation. The uncharacterized C15orf41 protein is involved in the formation of a functional complex structure. The uncharacterized C15orf41 protein is thermostable, unstable and acidic. This is associated with TPD (Treponema Pallidum) domain (135 to 265 residue position) and three PTM sites such as K50 (Acetylation), T114 (Phosphorylation) and K176 (Ubiquitination). C15orf41 is paralogous to isoform-1 (gi|194018542|) and open reading frame isoform-CRA_c (gi|119612744|) of Homo sapiens located at chromosome 15. It interacts with the human ATP (Adenosine Triphosphate) binding domain 4 (ATPBD4) having similarity score 0.725 as per protein-protein interaction (PPI) network analysis. This data provides valuable insights towards the functional characterization of human gene C15orf41.

Identification of in vivo-induced antigen Tp0462 of Treponema pallidum and evaluation of its application to serodiagnosis of syphilis

Objective To screen and identify the in vivo-induced antigen Tp0462 of Treponema pallidum (Tp) , and to evaluate its value for clinical serological diagnosis of syphilis. Methods Genome-wide DNA was extracted from the Tp Nichols strain, and polymerase chain reaction (PCR) was performed to amplify the Tp0462 gene. A recombinant plasmid pET30a (+) -Tp0462 was constructed and transfected into the Escherichia coli (E.coli) Rosetta (DE3) strain. Recombinant protein Tp0462 was abundantly expressed, purified and identified. A total of 18 New Zealand rabbits were randomly and equally divided into 3 groups: viable Tp-incubating group incubated with viable Tp in the testes, inactived Tp-incubating group incubated with ultraviolet irradiation-killed Tp in the testes, and control group receiving no treatment. After incubation, blood samples were collected at different time points, and the sera were isolated for identification of characteristics of in vivo-induced antigen Tp0462. Enzyme-linked immunosorbent assay for Tp0462 (Tp0462-ELISA) , Treponema pallidum particle agglutination assay (TPPA) , preliminary syphilis screening ELISA and rapid plasma reagin (RPR) card test were applied in 336 clinical serum samples from patients with syphilis, so as to preliminarily evaluate the value of Tp0462 for the diagnosis of syphilis. Results The optimum conditions for expression of the recombinant plasmid Tp0462-pET30a (+) in E.coli Rosetta (DE3) strains were the treatment with 0.5 mmol/L isopropyl thiogalactoside (IPTG) on a shaker at 180 rpm for 4 hours. In the viable Tp-incubating group, the serum level of specific anti-Tp0462 antibody sharply increased from week 2, and went steady after week 5. However, the specific anti-Tp0462 antibody maintained a low level in the inactived Tp-incubating group and the control group. The viable Tp-incubating group showed a significantly higher level of specific anti-Tp0462 antibody compared with the inactived Tp-incubating group and the control group (both P < 0.05) , while no significant difference was observed between the inactived Tp-incubating group and the control group (P = 0.256) . The level of anti-Tp92 antibody was significantly higher in the viable Tp-incubating group and the inactived Tp-incubating group than in the control group (P < 0.05) , while there was no significant difference between the viable Tp-incubating group and the inactived Tp-incubating group (P = 0.127) . Compared with TPPA, the sensitivity, specificity, consistency rate and area under the curve (AUC) of Tp0462-ELISA for the diagnosis of syphilis were 91.7%, 98.8%, 95.2% and 0.997 respectively. Tp0462-ELISA was consistent to preliminary syphilis screening ELISA and RPR with a Kappa coefficient of 0.846 and 0.293, respectively. Conclusion Tp0462-ELISA has shown evidently higher sensitivity and specificity in the serodiagnosis of syphilis, and Tp0462 can serve as promising antigens for the diagnosis of syphilis. Key words: Syphilis; Treponema pallidum; Syphilis serodiagnosis; In vivo induced antigen; Tp0462

Characteristics of Treponema pallidum-induced macrophage-derived exosomes and its effect on proliferation of human umbilical vein endothelial cells

Objective To investigate characteristics of Treponema pallidum (Tp) -induced macrophage-derived exosomes and its effect on the proliferation of human umbilical vein endothelial cells (HUVEC) . Methods Tp strains were collected from the testis of male rabbit, which were infected with Tp (Nichols strain) . The human mononuclear macrophages (THP-1) were induced into macrophages by incubation with propylene glycol methyl ether acetate (PMA) , and then the macrophages were divided into 2 groups: experimental group incubated with Tp for 12 hours followed by 48-hour normal culture, and control group receiving normal culture. After the treatment, exosome suspensions were collected, and exosomes were extracted by differential centrifugation and exoEasy Maxi Kit. Transmission electron microscopy and Western blot analyses were performed to identify the exosomes, and nanoparticle tracking analysis (NTA) was conducted to measure the diameters and concentrations of exosomes. In vitro cultured HUVECs were divided into 3 groups, which were cultured with the 10 μl of suspensions containing exosomes derived from Tp-stimulated macrophages at a concentration of 4.5 × 108/ml (experimental group) , 10 μl of suspensions containing exosomes derived from untreated macrophages at a concentration of 4.5 × 108/ml (control group) , and 10 μl of exosome eluents (exosome eluent group) , respectively. After the treatment, confocal laser scanning microscopy was performed to observe the phagocytosis of exosomes of HUVECs, and cell counting kit-8 to evaluate the proliferative activity of HUVECs. Results The exosomes were saucer-like microvesicles with diameters of 30-100 nm under the transmission electron microscope. Western blot analyses showed that membrane proteins CD63, CD9 and CD81 were abundantly expressed by exosomes. Under the same conditions, NTA revealed that there were no significant differences in the particle diameter (u = 1.90, P > 0.05) and concentration of exosomes (Z=-1.604, P= 0.109) between the experimental group and the control group. After co-culture with HUVECs for 5 hours, confocal laser scanning microscopy showed scatteredly distributed exosomes with green fluorescence in the HUVECs in the experimental group and control group. After 12-hour co-culture with the exosome suspensions, the proliferative activity of HUVECs was significantly higher in the experimental group and the control group than in the exosome eluent group (both P 0.05) . At 72 hours, no significant differences in the proliferative activity of HUVECs were observed among the experimental group, the control group and the exosome eluent group (all P > 0.05) . Conclusions The exosomes secreted by THP-1 cells-derived macrophages evidently increased the proliferative activity of HUVECs within 48 hours, which peaked at 48 hours. After the stimulation with Tp, the exosomes secreted by THP-1 cells-derived macrophages were similar to those without Tp stimulation in morphology, size and concentration, and only increased the proliferative activity of HUVECs within 12 hours. Key words: Treponema pallidum; Macrophages; Exosomes; Human umbilical vein endothelial cells; Cell proliferation

Evaluation of prototype IgA rapid test on diagnosis of early active syphilis

Objective To evaluate the application of Burnet Institute-made prototype IgA rapid test, a kind of point-of-care (POC) testing, in the diagnosis of early syphilis. Methods Totally, 455 stored serum samples in the Reference Laboratory of Sexually Transmitted Disease, the Institute of Dermatology were used to evaluate the application of the prototype IgA rapid test (IgA-POC) in the diagnosis of early syphilis. According to resluts of Treponema pallidum hemagglutination assay (TPHA) , rapid plasma reagin card test (RPR) , and enzyme-linked immunosorbent assay for IgM antibodies (IgM-ELISA) , these stored samples were divided into 3 groups: uninfected group, previously infected group and early active syphilis group. IgA-POC test was performed in the 3 groups to evaluate its diagnostic performance for active syphilis, and researchers were blind to the group information. Results The prototype IgA-POC test had a sensitivity of 92.6% (147/163) for the early active syphilis group, a specificity of 72.22% (104/144) for the previously infected group, and a specificity of 97.97% (145/148) for the uninfected group. The total specificity of the prototype IgA-POC test was 85.27%, which met the minimum requirement of WHO for the POC test. The prototype IgA-POC test showed a significantly higher sensitivity for the diagnosis of early active syphilis compared with the IgM-ELISA (59.51%, Z = 6.88, P < 0.05) , but a significantly lower specificity for the diagnosis of previous syphilis infection compared with the IgM-ELISA (98.61%, Z= 6.18, P < 0.05) . Moreover, no significant difference in the specificity for the diagnosis of non-infection was observed between the prototype IgA-POC test and IgM-ELISA (Z= 1.16, P= 0.25) . Conclusion The prototype IgA-POC test has better capacity for the diagnosis of early active syphilis compared with the IgM-ELISA, so it can be applied to the screening of early active syphilis. Key words: Syphilis; Syphilis serodiagnosis; Point of care testing

Sensitive detection of Treponema pallidum DNA from the whole blood of patients with syphilis by the nested PCR assay

The aim of this work was to investigate the application of the nested PCR assay for the detection of Treponema pallidum (TP) DNA from the blood of patients with different stages of syphilis. In this study, a nested PCR method targeting the Tpp47 and polA genes (Tpp47-Tp-PCR and polA-Tp-PCR) was developed to detect TP-DNA in whole blood samples collected from 262 patients with different stages of syphilis (84 primary syphilis, 97 secondary syphilis, and 81 latent syphilis patients). The PCR assay detected T. pallidum DNA in 53.6% and 62.9% of the patients with primary and secondary syphilis, respectively, which was much higher than the detection levels in patients with latent syphilis (7.4%) (both p < 0.001). For primary syphilis, a low RPR (0–16) was correlated with a higher detection rate of TP-DNA, whereas for secondary syphilis, the higher detection rate of blood TP-DNA was correlated with higher blood RPR titers (at or beyond 32). For latent syphilis, TP-DNA was only detectable by PCR in the early phase of the latent infection. Thus, blood RPR titers were correlated with the blood T. pallidum burden, but the correlations varied with primary and secondary syphilis. The results indicate that nested PCR is a sensitive method for detecting blood TP-DNA and is especially useful for detecting early syphilis including primary syphilis and secondary syphilis. The findings also suggest that the PCR assay may be used to complement other methods to enhance the diagnosis of syphilis.