Use of Treponema pallidum PCR in testing of ulcers for diagnosis of primary syphilis

PCR-detection rates of T. pallidum ssp. pallidum in swab samples from the Czech Republic (2004-2022): Combined RPR, IgM, and PCR tests efficiently detect active syphilis

Syphilis is a multistage sexually transmitted disease caused by Treponema pallidum ssp. pallidum (TPA). This study analyzed clinical samples collected from patients with a diagnosed syphilis infection from 2004-2022, isolated in the Czech Republic. Mucocutaneous swab samples (n = 543) from 543 patients were analyzed, and from these samples, 80.11 % (n = 435) were PCR positive, and 19.89 % (n = 108) were PCR negative for TPA DNA. Swabs were more often positive when collected from syphilis patients in the primary and secondary stages, compared to the latent or unknown stage. There was no significant difference in PCR positivity between the primary and secondary stages (p = 0.099). In IgM-positive patients, a statistically significant association with PCR-positivity was found in samples from seropositive (p = 0.033) and serodiscrepant (RPR negative) patients (p = 0.0006). When assessing our laboratory-defined cases of syphilis, the RPR, IgM, and PCR tests were similarly effective (within the range of 80.1-86.1 %). However, parallel testing with these methods was even more effective, i.e., RPR + PCR was 96.1 % effective and RPR + IgM + PCR was 97.8 % effective. A combination of RPR + PCR, or a combination of all three tests (RPR, IgM, and PCR) can therefore be used to reliably detect active syphilis cases, including reinfections. Our findings show that the reverse algorithm for detecting syphilis could be substantially improved by adding IgM and PCR testing.

Multiplex Loop-Mediated Isothermal Amplification Coupled Lateral Flow Assay for Point-of-Care Detection of Syphilis

Syphilis is a re-emerging sexually transmitted disease caused by the pathogenic spirochete T. pallidum. Every year more than 5 million cases are reported globally. The current diagnostic methods are primarily based on serological assays, which are less sensitive at an early stage of infection. To improve the disease diagnosis, there is a need to develop a rapid, simple, sensitive, and cost-effective point-of-care application, which plays an effective role in the detection of syphilis infection. In this study, we developed a multiplex loop-mediated isothermal amplification coupled lateral flow assay (multiplex LAMP-LFA) for the detection of syphilis. Two different genes, the target amplicon (polA) and the internal control amplicon (human RNase P) were amplified using multiplex LAMP assay. The amplified products were detected using LFA strips coated with Anti-FITC and Anti-DIG antibodies within 5 minutes of flowthrough. Multiplex LAMP LFA detection limit was found to be 3.8 × 103 copies/mL with high specificity. The developed strip was tested with 130 clinically suspected cases and 50 healthy individuals. With the clinical samples, the method shows a sensitivity of 93.84% and a specificity of 100%. The Multiplex LAMP LFA has the potential to overcome the limitations of both Non Treponemal tests and Treponemal tests which are prone to prozone effects and expensive reagents respectively. The proposed method holds promise for sensitive, rapid, and visual detection of T. pallidum, thereby offering a facile and affordable alternative to existing diagnostic methods. This approach is poised to advance the development of point-of-care diagnostics, addressing a critical need in public healthcare, particularly in resource-limited settings.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12088-024-01308-4.

Resurgence of congenital syphilis: new strategies against an old foe

Congenital syphilis is a major global cause of fetal loss, stillbirth, neonatal death, and congenital infection. In 2020, the global rate of congenital syphilis was 425 cases per 100 000 livebirths-substantially higher than WHO's elimination target of 50 cases per 100 000 livebirths. Case rates are rising in many high-income countries, but remain low compared with those in low-income and middle-income settings. This Review aims to summarise the current epidemiology and knowledge on transmission and treatment of syphilis in pregnancy, and proposes measures to reduce the rising incidence seen worldwide. We also describe emerging diagnostic and treatment tools to prevent vertical transmission and improve management of congenital syphilis. Finally, we outline a programme of public health priorities, which include research, clinical, and preventive strategies.

Resurgence of syphilis: focusing on emerging clinical strategies and preclinical models

Syphilis, a sexually transmitted disease (STD) caused by Treponema pallidum (T. pallidum), has had a worldwide resurgence in recent years and remains a public health threat. As such, there has been a great deal of research into clinical strategies for the disease, including diagnostic biomarkers and possible strategies for treatment and prevention. Although serological testing remains the predominant laboratory diagnostic method for syphilis, it is worth noting that investigations pertaining to the DNA of T. pallidum, non-coding RNAs (ncRNAs), chemokines, and metabolites in peripheral blood, cerebrospinal fluid, and other bodily fluids have the potential to offer novel perspectives on the diagnosis of syphilis. In addition, the global spread of antibiotic resistance, such as macrolides and tetracyclines, has posed significant challenges for the treatment of syphilis. Fortunately, there is still no evidence of penicillin resistance. Hence, penicillin is the recommended course of treatment for syphilis, whereas doxycycline, tetracycline, ceftriaxone, and amoxicillin are viable alternative options. In recent years, efforts to discover a vaccine for syphilis have been reignited with better knowledge of the repertoire of T. pallidum outer membrane proteins (OMPs), which are the most probable syphilis vaccine candidates. However, research on therapeutic interventions and vaccine development for human subjects is limited due to practical and ethical considerations. Thus, the preclinical model is ideal for conducting research, and it plays an important role in clinical transformation. Different preclinical models have recently emerged, such as in vitro culture and mouse models, which will lay a solid foundation for clinical treatment and prevention of syphilis. This review aims to provide a comprehensive summary of the most recent syphilis tactics, including detection, drug resistance treatments, vaccine development, and preclinical models in clinical practice.

Early syphilis in Guangzhou, China: presentation, molecular detection of Treponema pallidum , and genomic sequences in clinical specimens and isolates obtained by rabbit infectivity testing

Background

The global resurgence of syphilis requires novel prevention strategies. Whole genome sequencing (WGS) of Treponema pallidum ( TPA ) using different specimen types is essential for vaccine development.

Methods

Patients with primary (PS) and secondary (SS) syphilis were recruited in Guangzhou, China. We collected ulcer exudates and blood from PS participants, and skin biopsies and blood from SS participants for TPA polA polymerase chain reaction (PCR); ulcer exudates and blood were also used to isolate TPA strains by rabbit infectivity testing (RIT). TPA WGS was performed on 52 ulcer exudates and biopsy specimens and 25 matched rabbit isolates.

Results

We enrolled 18 PS and 51 SS participants from December 2019 to March 2022. Among PS participants, TPA DNA was detected in 16 (89%) ulcer exudates and three (17%) blood specimens. Among SS participants, TPA DNA was detected in 50 (98%) skin biopsies and 27 (53%) blood specimens. TP A was isolated from 48 rabbits, with a 71% (12/17) success rate from ulcer exudates and 69% (36/52) from SS bloods. Twenty-three matched SS14 clade genomes were virtually identical, while two Nichols clade pairs had discordant tprK sequences. Forty-two of 52 unique TPA genomes clustered in an SS14 East Asia subgroup, while ten fell into two East Asian Nichols subgroups.

Conclusions

Our TPA detection rate was high from PS ulcer exudates and SS skin biopsies and over 50% from SS whole blood, with RIT isolation in over two-thirds of samples. Our results support the use of WGS from rabbit isolates to inform vaccine development.

Summary

We performed Treponema pallidum molecular detection and genome sequencing from multiple specimens collected from early syphilis patients and isolates obtained by rabbit inoculation. Our results support the use of whole genome sequencing from rabbit isolates to inform syphilis vaccine development.

Refining Timely Diagnosis of Early Syphilis by Using Treponema pallidum PCR or IgM Immunoblotting Next to Conventional Serology for Syphilis

Treponema pallidum subsp. pallidum is a fastidious spirochete and the etiologic agent of syphilis, a sexually transmitted infection (STI). Syphilis diagnoses and disease staging are based on clinical findings and serologic testing. Moreover, according to most international guidelines, PCR analysis of swab samples from genital ulcers is included in the screening algorithm where possible. It has been suggested that PCR might be omitted from the screening algorithm due to low added value. As an alternative to PCR, IgM serology might be used. In this study, we wanted to establish the added value of PCR and IgM serology for diagnosing primary syphilis. Added value was defined as finding more cases of syphilis, preventing overtreatment, or limiting the extent of partner notification to more recent partners. We found that both PCR and IgM immunoblotting could aid the timely diagnosis of early syphilis in ~24% to 27% of patients. PCR has the greatest sensitivity and can be applied to cases with an ulcer with suspected reinfection or primary infection. In the absence of lesions, the IgM immunoblot could be used. However, the IgM immunoblot has better performance in cases with suspected primary infection than in reinfections. The target population, testing algorithm, time pressures, and costs should determine whether either test provides sufficient value to be implemented in clinical practice.

Advances in Diagnostics of Sexually Transmitted Infections

Sexually transmitted infections (STIs) are caused by various pathogens, many of which have common symptoms. Diagnostic tests are critical to supporting clinical evaluations in making patient management decisions. Molecular diagnostics are the preferred test type when available, especially in asymptomatic patients for many STIs. However, for some infections, serology offers the best insight into infectious status. Clinicians should be aware of the performance characteristics of the available STI diagnostic tests and understand how to use them. Point-of-care tests are helpful to implement rapid and accurate treatment responses, which are particularly helpful in certain at-risk populations.

Specific detection of Treponema pallidum in clinical samples: validation of a qPCR assay combining two genomic targets

OBJECTIVES

We evaluated a real-time quantitative PCR (qPCR) for detection of the Treponema pallidum (TP) genome in clinical samples through simultaneous detection of two genomic targets.

METHODS

We performed qPCR with TaqMan technology using two TP genes, polA and tpp47, as targets, with an internal positive control. The qPCR assay was compared with syphilis diagnosis based on a combination of clinical examination, serological results and inhouse nested PCR (nPCR). Samples were analysed at the National Reference Center for STIs at Cochin Hospital in Paris.

RESULTS

In total, from October 2010 to December 2016, 320 documented clinical samples (mucosal and cutaneous swabs) were collected from patients with or without syphilis attending STI centres in France. The qPCR had an overall sensitivity of 89% (95% CI 85.1% to 92.1%), a specificity of 100%, a positive predictive value of 100% and a negative predictive value of 88% (95% CI 84.3% to 91.5%). The agreement between qPCR and nPCR results was 94% (κ=0.88, 95% CI 0.83 to 0.93). Calibration of the qPCR assay, by cloning both the polA and tpp47 genes, defined the detection threshold as 1 copy/µL of DNA elution.

CONCLUSIONS

We validated a new qPCR for detecting the TP genome in clinical samples with excellent sensitivity and specificity. The cloning of polA and tpp47 genes for calibration would be interesting in the evaluation of bacterial loads in samples.

Syphilis in pregnancy: an ongoing public health threat

Syphilis is a treponemal infection that can be acquired sexually, hematogenously, or via vertical transmission from mother to infant. Despite evidence-based curative treatment options with penicillin, it remains a public health threat with increasing prevalence over recent years. Congenital syphilis, a condition where a fetus acquires the infection during pregnancy, can lead to stillbirth, miscarriage, preterm birth, birth defects, and lifelong physical or neurologic changes. Congenital syphilis rates in the United States increased by 261% from 2013 to 2018 and continue to increase in 2021. The only recommended treatment for syphilis in pregnancy is benzathine penicillin G because evidence of decreased risk of congenital syphilis with other modalities is lacking. Testing for syphilis is complex and includes either the reverse-sequence algorithm or the traditional algorithm. Determination of the clinical stage of syphilis includes incorporation of the previous treatment sequence and physical examination. The goal of this review was to discuss the current evidence about optimal treatment and testing during pregnancy to optimize maternal health and prevent congenital syphilis.

Clinical and laboratory aspects of condylomata lata lesions of syphilis

OBJECTIVES

Condylomata lata are a less common but distinctive syphilitic lesion. Variable theories as to their nature and origin exist. The aim of this study was to determine the clinical and laboratory characteristics of condylomata lata by determining (1): the most closely aligned stage of syphilis, based on the rapid plasma reagin (RPR) titre; (2) symptom duration and (3) Treponema pallidum PCR cycle threshold (C_T) values, as an indicator of organism load.

METHODS

This was a retrospective study of patients with T. pallidum PCR-positive condylomata lata lesions, attending a clinic in Melbourne, Australia, between 2011 and 2021. Syphilis serology was undertaken and RPR titres compared between condylomata lata, primary and secondary syphilis cases.

RESULTS

51 cases with T. pallidum PCR-positive condylomata lata were included. 41 cases were in men, 40 of whom were men who have sex with men (MSM), and 10 in women. Twelve of 51 (24%) cases were in HIV-positive MSM. Thirty-three of 51 (65%) had other mucocutaneous signs of secondary syphilis; 18 (35%) had no other signs of secondary syphilis. The median RPR titre among the 51 condylomata lata cases was 1:128, compared with the median RPR titre of primary syphilis (1:4) and of secondary syphilis (1:128). The median duration of lesions was 24 (IQR 10-60) days, with no significant difference between those with and without other signs of secondary syphilis (p=0.75). Median C_T values for condylomata lata (C_T=31) and primary syphilis (C_T=31) were significantly lower than for other secondary syphilis lesion types (C_T=33), indicating higher T. pallidum loads for condylomata lata and primary lesions compared with other secondary syphilis lesion types.

DISCUSSION

These findings support condylomata lata as lesions that occur during the secondary stage of syphilis and which are likely to be highly infectious.

Development of multiplex HRM-based loop-mediated isothermal amplification method for specific and sensitive detection of Treponema pallidum

Syphilis is a sexually transmitted disease caused by the spirochaete bacterium Treponema pallidum. This study has developed a multiplex High-Resolution Melt-curve Loop-mediated isothermal amplification (multiplex HRM-LAMP) assay targeting the marker genes polA and tprL to detect T. pallidum. The multiplex HRM-LAMP assay conditions were optimized at 65 °C for 45 min. Real-time melt-curve analysis of multiplex HRM-LAMP shows two melt-curve peaks corresponding to polA and tprL with a Tm value of 80 ± 0.5 °C and 87 ± 0.5 °C, respectively. The detection limit of multiplex HRM-LAMP was found to be 6.4 × 10^-4 ng/μL (3.79 copies/μL) of T. pallidum. The specificity was evaluated using seven different bacterial species, and the developed method was 100% specific in detecting T. pallidum. A total of 64 blood samples of T. pallidum suspected cases were used to validate the assay method. The clinical validation showed that the assay was 96.43% sensitive and 100% specific in detecting syphilis. Thus, the developed method was more rapid and sensitive than other available methods and provides a multigene-based diagnostic approach to detect T. pallidum.

Detection of Treponema pallidum DNA during early syphilis stages in peripheral blood, oropharynx, ano-rectum and urine as a proxy for transmissibility

Background

Syphilis diagnosis may be challenging, especially in the asymptomatic and early clinical stages. We evaluated the presence of Treponema pallidum DNA (TP-DNA) in various sample types to elucidate transmissibility during various syphilis stages.

Methods

The study was conducted at the Amsterdam Centre for Sexual Health. We included adult men who have sex with men (MSM), who were suspected of having syphilis. The 2020 European guidelines definitions were followed for the diagnosis and staging of syphilis. Using a polymerase chain reaction (PCR) targeting the polA gene of Treponema pallidum (TP-PCR), we tested the following study samples on TP-DNA: peripheral blood, oropharyngeal swab, ano-rectal swab, and urine.

Results

From November 2018 to December 2019 we included 293 MSM. Seventy clients had primary syphilis, 73 secondary syphilis, 86 early latent syphilis, 14 late latent syphilis, 23 treated syphilis, and 27 had no syphilis. TP-DNA was detected in at least 1 study sample in 35/70 clients with primary syphilis (2/70 peripheral blood, 7/70 oropharynx, 13/70 ano-rectum, and 24/70 urine); in 62/73 clients with secondary syphilis (15/73 peripheral blood, 47/73 oropharynx, 37/73 ano-rectum, and 26/73 urine); and in 29/86 clients with early latent syphilis (5/86 peripheral blood, 21/86 oropharynx, 11/86 ano-rectum, and 6/86 urine). TP-DNA was not detected in clients with late latent syphilis or treated syphilis, nor in clients without syphilis.

Conclusions

TP-DNA was frequently detected in various sample types in the absence of lesions. This is in line with the high transmission rate of syphilis and opens diagnostic opportunities for early presymptomatic syphilis stages.

Is dark-field microscopy still useful for the primary syphilis diagnosis in the 21ST century?

INTRODUCTION

Serological test for primary syphilis could be negative the first 5-15 days. The aim of this study was to evaluate the benefit of including dark field microscopy (DFM) in the diagnosis algorythm for primary syphilis.

MATERIALS/METHODS

Patients attended to a sexual transmission diseases clinic of Madrid, from 2015 to 2019, for a genital ulcer with clinical suspicion of primary syphilis. They were tested for DMF and serological test (EIA/TPPA/RPR).

RESULTS

Over the total amount of samples (806), 53.2% (429) were positive for DFM. Thus, the 48% of the 429 patients had negative serological test (EIA/RPR) of which the 77.6% were positive at TPPA.

CONCLUSIONS

DFM allows primary syphilis early diagnosis, even without serological test. If no direct detection methods are available, for patients without history of syphilis, TPPA could help to diagnose primary syphilis.

Predicting asymptomatic neurosyphilis using peripheral blood indicators

BACKGROUND

The high misdiagnosis rate of asymptomatic neurosyphilis (ANS) has long challenged infectious disease clinicians. We aim to develop a model for diagnosing ANS in asymptomatic syphilis (AS) patients without CSF indicators.

RESULTS

277 AS patients with HIV-negative and underwent lumbar puncture were enrolled in this horizontal study.The area under the curve for predicting ANS by CSF leukocytes and protein was 0.643 and 0.675 [95% CI, 0.583-0.699VS.0.616-0.729]. Through LRM, the AUC increased to 0.806 [95% CI, 0.732-0.832], and the Youden's index was 0.430. If the score is ≤ 0.159, ANS can be excluded with a predictive value of 92.9%; we can identify ANS while the score is over 0.819, with a predictive value of 91.7% and a specificity of 99.25%. This study showed that the LRM can diagnose ANS in AS patients effectively.

CONCLUSION

Given a large number of misdiagnosis ANS patients and CSF results' insufficiency, the model is more practical. Our research will help clinicians track suspected syphilis, especially those who cannot accept the CSF test.

Treponema pallidum PCR testing for diagnosis of mucocutaneous ulcers suspicious for syphilis

BACKGROUND

Primary syphilis is characterised by the appearance of an ulcerated lesion (chancre) on the anogenital or oral mucosa from which Treponema pallidum DNA may be detectable by PCR. Serological tests for syphilis may be non-reactive in early infection, even after the appearance of a chancre. We reviewed the use of a multiplex-PCR (M-PCR) test to determine the added value of T. pallidum DNA detection in the management of individuals presenting with mucocutaneous ulceration at a sexual health service in central London.

METHODS

We performed a cross-sectional analysis of all individuals with detectable T. pallidum DNA from September 2019 to April 2020. Electronic patient records were reviewed and concomitant results for treponemal serology and/or rapid plasma reagin (RPR) extracted, along with demographic data, history of syphilis and indices of sexual behaviour including number of sexual partners contacted. Any subsequent treponemal serology and RPR results were also reviewed.

RESULTS

M-PCR swab specimens were performed in 450 individuals, of whom 63 (14%) had detectable T. pallidum DNA; 60 of 63 (95%) were gay or bisexual men and 11 of 63 (17%) were living with HIV. A history of treated syphilis was present in 17 of 63 (27%). Same-day treponemal serology/RPR testing was performed in 58 of 63 (92%) patients. Of the 58 who had same-day syphilis serology/RPR, 9 (16%) had their syphilis infection confirmed by treponemal DNA PCR alone. A total of 165 partners were traced as contacts of infection, of whom 25 (15%) were contacts of individuals diagnosed by M-PCR testing alone.

CONCLUSION

In individuals with T. pallidum PCR-positive lesions, around one in six in our cohort were negative on standard diagnostic serological tests for syphilis. Treponemal DNA testing is an important addition to serological assays in individuals with mucocutaneous ulceration who are at risk of recent syphilis infection and facilitates early diagnosis and contact tracing.

Intra-couple discordance in preconception syphilis screening for both spouses: a national and population-based survey in China, 2013-2018

OBJECTIVE

The antenatal screening strategy remains inadequate for eliminating congenital syphilis. To further eliminate maternal fetal transmission, preconception syphilis screening is considered an option. In this study, we investigated syphilis seropositivity and intra-couple discordance among married couples planning a pregnancy in China to provide essential baseline evidence for preconception syphilis screening.

DESIGN

Population-based survey.

SETTING

National preconception registered data.

POPULATION

Married Chinese couples planning conception within 6 months between 2013 and 2018.

METHODS

Syphilis was screened using rapid plasma reagin (RPR); infection self-reporting and sociodemographic characteristics were collected through questionnaires and medical records, respectively. r 3.2.2 and arcgis 10.2 were used for statistical analyses and geographic mapping.

MAIN OUTCOME MEASURES

RPR seropositivity.

RESULTS

Among 31 955 041 couples, 29 737 172 (93.06%) had complete RPR results for both spouses; of those, 0.62% (186 100) were seropositive, with dramatic intra-couple discordance, with 0.33% positivity in wives, 0.24% positivity in husbands and 0.05% positivity in both spouses. Across time, both seropositivity and intra-couple discordance remained stable. Seropositivity in different regions varied significantly, with provincial rates ranging geographically from Tibet (0.8%) to Hebei (0.2%) (P < 0.05). Economic level was an independent factor for this regional variation, with seropositivity increasing as gross domestic product income decreased (P < 0.05).

CONCLUSIONS

Intra-couple discordance in seropositivity for syphilis is notable among couples, with a considerable rate of pre-existing syphilis before pregnancy. Thus, screening both spouses during integrated preconception health care is recommended for further eliminating maternal-fetal transmission.

TWEETABLE ABSTRACT

Intra-couple discordance in seropositivity for syphilis is notable among couples, with a considerable rate of pre-existing syphilis before pregnancy. Screening both spouses during integrated preconception health care is recommended to further eliminate maternal-fetal transmission.

Hard bilateral syphilitic testes with vasculitis: a case report and literature review

BACKGROUND

We report the case of a patient with syphilitic testicular gumma and vasculitis with adrenal failure due to chronic steroid use.

CASE PRESENTATION

A 63-year-old male presented with hard right eye swelling and very firm bilateral testes on palpation, which he had for 2 years. Testicular tumor markers were negative; syphilis test was positive. Radiological examination suggested aortitis and bilateral testicular malignancy. The patient received ampicillin for the infection and prednisolone for vasculitis. Left orchidectomy was performed to confirm the presence of testicular tumor; histological examinations revealed granulomatous orchitis. The prednisolone doses were adjusted because of relapses and adverse effects of steroid use. Unfortunately, the patient died in the intensive care unit because of uncontrolled blood pressure and pneumonia.

CONCLUSIONS

This is a rare case of syphilis with testicular involvement and vasculitis. This report shows the importance of broadening the differential diagnoses of testicular firmness.

Analytical Performance Characteristics of a New Transcription-Mediated Amplification Assay for Treponema pallidum

This study evaluated the performance characteristics of a new research-use-only transcription-mediated amplification (TMA) assay for the detection of rRNA from Treponema pallidum. Analytical sensitivity determined using dark-field microscopy-quantitated T. pallidum was 1.4 organisms/ml (95% confidence interval [CI], 0.7 to 6.33 organisms/ml). Dilution of in vitro-transcribed (IVT) T. pallidum RNA in Aptima sample transport medium (STM) yielded 100% positivity (n = 3) at 10 copies/ml (4 copies/reaction). Analytical specificity testing of nontarget microorganisms (n = 59), including the closely related nonsyphilis treponemes Treponema denticola and Treponema phagedenis, yielded 0% positivity. TMA testing of mucosal swab specimens collected from men who have sex with men (MSM) attending a sexually transmitted disease clinic yielded 1.8% (17/944) positive results. A collection of 56 serum specimens obtained from a separate cohort of patients with known rapid plasma reagin (RPR) statuses and clinical diagnoses of syphilis was 19.6% (11/56) TMA positive overall and 29.7% (11/37) positive among subjects with syphilis diagnoses, including 8 (36.3%) of 22 persons with primary or secondary syphilis, 2 (20%) of 10 persons with early latent syphilis, and 1 (20%) of 5 persons with late latent or unstaged syphilis. None (0%) of the 18 RPR-positive sera from patients with histories of treated syphilis were TMA positive. These results show that TMA is an analytically sensitive and specific method for the detection of T. pallidum rRNA and is compatible with serum specimens in addition to pharyngeal and rectal mucocutaneous swab specimens. Automated real-time TMA testing for T. pallidum may be useful as an adjunctive method with serology for screening and diagnostic testing of selected patient populations for syphilis.

Analytical Performance Characteristics of a New Transcription-Mediated Amplification Assay for Treponema pallidum

This study evaluated the performance characteristics of a new research-use-only transcription-mediated amplification (TMA) assay for the detection of rRNA from Treponema pallidum. Analytical sensitivity determined using dark-field microscopy-quantitated T. pallidum was 1.4 organisms/ml (95% confidence interval [CI], 0.7 to 6.33 organisms/ml). Dilution of in vitro-transcribed (IVT) T. pallidum RNA in Aptima sample transport medium (STM) yielded 100% positivity (n = 3) at 10 copies/ml (4 copies/reaction). Analytical specificity testing of nontarget microorganisms (n = 59), including the closely related nonsyphilis treponemes Treponema denticola and Treponema phagedenis, yielded 0% positivity. TMA testing of mucosal swab specimens collected from men who have sex with men (MSM) attending a sexually transmitted disease clinic yielded 1.8% (17/944) positive results. A collection of 56 serum specimens obtained from a separate cohort of patients with known rapid plasma reagin (RPR) statuses and clinical diagnoses of syphilis was 19.6% (11/56) TMA positive overall and 29.7% (11/37) positive among subjects with syphilis diagnoses, including 8 (36.3%) of 22 persons with primary or secondary syphilis, 2 (20%) of 10 persons with early latent syphilis, and 1 (20%) of 5 persons with late latent or unstaged syphilis. None (0%) of the 18 RPR-positive sera from patients with histories of treated syphilis were TMA positive. These results show that TMA is an analytically sensitive and specific method for the detection of T. pallidum rRNA and is compatible with serum specimens in addition to pharyngeal and rectal mucocutaneous swab specimens. Automated real-time TMA testing for T. pallidum may be useful as an adjunctive method with serology for screening and diagnostic testing of selected patient populations for syphilis.

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

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

Comparative Analysis of Molecular and Serologic Testing for Primary Syphilis: A Population-Based Cohort Study

Rising rates of syphilis (T. pallidum; Tp) requires rapid diagnosis and treatment to manage the growing epidemic. Syphilis serology is imperfect and requires interpretation of multiple tests while molecular diagnostics allows for potential yes-no identification of highly infective, primary anogenital lesions. Accuracy of this testing modality has thus far been limited to small, highly selective studies. Therefore, we retrospectively assessed a large, adult population of patients with anogenital lesions seen at Sexually Transmitted Infection (STI) clinics in Alberta, Canada who were screened for syphilis and herpes simplex (HSV) 1/2 using PCR to evaluate Tp-PCR versus serology to diagnose primary syphilis. 114 (3.1%) of the 3,600 adult patients had at least one Tp-PCR+ anogenital lesion with 99 (2.8%) patients having newly positive syphilis serology (new INNO-LIA positive or 4-fold RPR increase). Tp-PCR had a sensitivity of 49.3% (95% CI 42.6-56.1) and specificity of 99.9% (99.7-100.0). Positive predictive values and negative predictive values in the study population or when corrected for provincial prevalence were 97.4% (92.5-99.5) or 0.4% (0.4-1.2) and 96.7% (96.1-97.3) or 100.0% (100.0-100.0), respectively. Positive and negative likelihood ratios were estimated at 555 (178-1733) and 0.5 (0.4-0.6), respectively. Review of all Tp-PCR performed with or without exclusion of HSV-positive lesions resulted in no significant change in Tp-PCR characteristics. Interestingly, 12 of the Tp-PCR+ samples had negative serology at time of lesion sampling but became positive within our 28-day testing window. Overall, this study further supports the use of Tp-PCR as an accurate assay to rapidly identify, treat, and prevent the spread of primary syphilis.

Timing of primary syphilis treatment and impact on the development of treponemal antibodies: a cross-sectional clinic-based study

BACKGROUND

Serology is negative in a proportion of primary syphilis cases where Treponema pallidum PCR testing is positive. We aimed to identify discordant, T. pallidum PCR-positive, serology-negative primary syphilis cases and any clinical or laboratory factors associated with failure to subsequently seroconvert.

METHODS

Serodiscordant primary syphilis cases that were T. pallidum PCR-positive and serology-negative (including rapid plasma reagin, T. pallidum particle agglutination, T. pallidum enzyme immunoassay or T. pallidum chemiluminescence assay) were identified from the Melbourne Sexual Health Centre electronic records between April 2011 and December 2019. Clinical and laboratory associations were examined.

RESULTS

There were 814 primary syphilis cases in the study period and 38 (4.7%) were serodiscordant, 35 in men who have sex with men. Thirty-two had follow-up serology performed a median of 24 days later, of which 16 (50%) seroconverted, mostly (81%) within 6 weeks. Failure to seroconvert was significantly associated with treatment on day 1. Of the 12 cases treated on day 1, 10 (83%) failed to seroconvert compared with 6 of 20 (30%) among those who were treated after day 1.

DISCUSSION

Earlier treatment of primary syphilis can prevent the development of serological markers. T. pallidum PCR can identify primary syphilis lesions before the development of serological markers and improve diagnosis of early primary syphilis lesions. Serology alone will miss a proportion of primary syphilis infections and should be repeated if a diagnosis of syphilis is being considered.

Laboratory Diagnostic Tools for Syphilis: Current Status and Future Prospects

With the increasing number of patients infected with syphilis in the past 20 years, early diagnosis and early treatment are essential to decline syphilis prevalence. Owing to its diverse manifestations, which may occur in other infections, the disease often makes clinicians confused. Therefore, a sensitive method for detecting T. pallidum is fundamental for the prompt diagnosis of syphilis. Morphological observation, immunohistochemical assay, rabbit infectivity test, serologic tests, and nucleic acid amplification assays have been applied to the diagnosis of syphilis. Morphological observation, including dark-field microscopy, silver-staining, and direct fluorescent antibody staining for T. pallidum, can be used as a direct detection method for chancre specimens in primary syphilis. Immunohistochemistry is a highly sensitive and specific assay, especially in the lesion biopsies from secondary syphilis. Rabbit infectivity test is considered as a sensitive and reliable method for detecting T. pallidum in clinical samples and used as a historical standard for the diagnosis of syphilis. Serologic tests for syphilis are widely adopted using non-treponemal or treponemal tests by either the traditional or reverse algorithm and remain the gold standard in the diagnosis of syphilis patients. In addition, nucleic acid amplification assay is capable of detecting T. pallidum DNA in the samples from patients with syphilis. Notably, PCR is probably a promising method but remains to be further improved. All of the methods mentioned above play important roles in various stages of syphilis. This review aims to provide a summary of the performance characteristics of detection methods for syphilis.

Is dark-field microscopy still useful for the primary syphilis diagnosis in the 21ST century?

INTRODUCTION

Serological test for primary syphilis could be negative the first 5-15 days. The aim of this study was to evaluate the benefit of including dark field microscopy (DFM) in the diagnosis algorythm for primary syphilis.

MATERIALS/METHODS

Patients attended to a sexual transmission diseases clinic of Madrid, from 2015 to 2019, for a genital ulcer with clinical suspicion of primary syphilis. They were tested for DMF and serological test (EIA/TPPA/RPR).

RESULTS

Over the total amount of samples (806), 53.2% (429) were positive for DFM. Thus, the 48% of the 429 patients had negative serological test (EIA/RPR) of which the 77.6% were positive at TPPA.

CONCLUSIONS

DFM allows primary syphilis early diagnosis, even without serological test. If no direct detection methods are available, for patients without history of syphilis, TPPA could help to diagnose primary syphilis.

2020 European guideline on the management of syphilis

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

Resurgence of Syphilis in the United States: An Assessment of Contributing Factors

In the last decade, there has been a marked resurgence of syphilis in the United States despite the availability of effective treatments and previously reliable prevention strategies. The majority of cases are among the population of men who have sex with men (MSM); however, there has also been a recent increase among premenopausal women, coinciding with a concerning rise of congenital cases. The resurgence of syphilis can be largely attributed to changing social and behavioral factors, especially among young MSM. The biological association of syphilis with human immunodeficiency virus (HIV) transmission and acquisition is particularly alarming because of the increased individual and healthcare burden. In addition, some individual actions and public health efforts that are meant to reduce the risk of acquiring HIV may actually lead to risk compensation that facilitates the transmission of syphilis. Untreated syphilis is associated with detrimental health outcomes; therefore, both effective prevention strategies and treatment of this systemic disease have important short-term and long-term public health implications. This article offers a review of social and behavioral factors contributing to the current resurgence and recommendations for reducing syphilis incidence through medical and public health prevention strategies.

Treponema pallidum Nucleic Acid Amplification Testing To Augment Syphilis Screening among Men Who Have Sex with Men

Syphilis rates in much of the world are now at their highest levels in almost three decades, and new approaches to controlling syphilis, including diagnostic tests with shorter window periods, are urgently needed. We compared the sensitivity of syphilis serological testing using the rapid plasma reagin (RPR) test with that of the combination of serological testing and an experimental 23S rRNA Treponema pallidum real-time transcription-mediated amplification (TMA) assay performed on rectal and pharyngeal mucosal swabs. T. pallidum PCR assays for the tpp47 gene were performed on all TMA-positive specimens, as well as specimens from 20 randomly selected TMA-negative men. A total of 545 men who have sex with men (MSM) who were seen in a sexually transmitted disease clinic provided 506 pharyngeal specimens and 410 rectal specimens with valid TMA results. Twenty-two men (4%) were diagnosed with syphilis on the basis of positive RPR test results and clinical diagnoses, including 3 men with primary infections, 8 with secondary syphilis, 9 with early latent syphilis, 1 with late latent syphilis, and 1 with an unstaged infection. Two additional men were diagnosed based on positive rectal mucosal TMA assay results alone, and both also tested positive by PCR assay. At least 1 specimen was TMA positive for 12 of 24 men with syphilis (sensitivity, 50% [95% confidence interval [CI], 29 to 71%]). RPR testing and clinical diagnosis were 92% sensitive (95% CI, 73 to 99%) in identifying infected men. Combining mucosal TMA testing and serological testing may increase the sensitivity of syphilis screening in high-risk populations.

PCR detection for syphilis diagnosis: Status and prospects

Syphilis, a re‐emerging public health problem worldwide caused by Treponema pallidum subsp pallidum (T. pallidum), usually induces systemic and chronic inflammation in hosts who do not receive timely therapy after exposing to high‐risk factors such as leprous sexual contact. Before the treatment, rapid and accurate detection of syphilis is essential. However, the existing detection methods, which focus on the treponemal or non‐treponemal antibody test, both have inherent limitations. For instance, both of them cannot distinguish the stage and severity of syphilis. Non‐treponemal test such as RPR, which is generally deemed to be used for assessing treatment response, is influenced by biological false positives. Therefore, it is imperative to seek out a new and effective diagnostic test. With recent advancements in molecular biology and whole‐genome sequencing, the molecular diagnosis has increased in popularity, especially the use of polymerase chain reaction (PCR). Here, we firstly present a mini‐review on the research of PCR detection methods used for syphilis diagnosis over the past decade, and we then compare these methodologies to assess their potential and the challenges faced. This information can provide a fresh perspective to help researchers address the current challenges.

Congenital Syphilis: A Discussion of Epidemiology, Diagnosis, Management, and Nurses' Role in Early Identification and Treatment

BACKGROUND

Syphilis is caused by the spirochete bacterium Treponema pallidum. Syphilis left untreated, or inadequately treated during pregnancy, can result in congenital syphilis (CS). Congenital syphilis can lead to severe sequelae or fetal, neonatal, or infant death.

PURPOSE

To discuss the epidemiological trends, pathophysiology, diagnosis, and management of CS; the implications of CS upon the infant; as well as the importance of the nurse's role in the prompt identification of CS and the timely interventions needed to minimize sequelae.

METHODS

A literature search was completed using ProQuest, CINAHL, Google Scholar, and PubMed. Articles published within the past 10 years were included.

FINDINGS

Epidemiological trends of CS in the United States indicate that maternal syphilis infection and CS are on the rise. Risk factors include ethnicity, socioeconomic status, access to prenatal care, and sexual behaviors, as well as compliance with prenatal syphilis screening by prenatal providers. Risks of CS to the developing fetus begin at approximately 14 weeks. Timely treatment is necessary to minimize or eliminate mortality and morbidity.

IMPLICATIONS FOR PRACTICE

Evidence-based, interprofessional strategies, which promote a collaborative perinatal/neonatal preventative approach to care of the pregnant female, are indicated to reverse the increasing incidence of CS within the United States. Strategies prioritizing early identification and treatment of at-risk neonates are necessary to reduce/eliminate the devastating long-term consequences of CS upon this vulnerable population.

IMPLICATIONS FOR RESEARCH

The paucity of research, which focuses on CS, is most likely due to ethical concerns related to infants as research participants and provides an opportunity for future research. Future research could focus on factors that focus on maternal-fetal/maternal-child transmission of CS.

Update on syphilis and pregnancy

While the origins of syphilis remain unknown, it has long been recognized as an infectious entity with complex pathophysiology. In this review, we highlighted the epidemiology and risk factors associated with syphilis. The incidence of syphilis in most populations showed a consistent upward trend until the 1940s with the introduction of penicillin as the preferred treatment. The emergence of congenital syphilis and vertical transmission has been a direct result of heterosexual syphilis transmission. We also explore the microbiology and pathogenesis of Treponema pallidum as it directly correlates with its route of transmission and infectivity. The clinical features are best categorized into stages (primary, secondary, early, and late latent and tertiary). The primary stage presents as a characteristic chancre and inguinal adenopathy, while the secondary "bacteremia" stage has a predilection to dermatologic manifestations and constitutional symptoms. The latent phase of syphilis witnesses a quiescent period with variable relapse of symptoms and finally, one-third of untreated patients undergo tertiary syphilis years after the initial infection characterized by severe neurologic or cardiovascular symptomatology. We will also review the data collected for congenital syphilis from the CDC as this can manifest with stillbirth, neonatal death, and nonimmune hydrops. The diagnosis of syphilis focuses on a combination of nontreponemal and treponemal antibody tests with the CDC recommending a traditional algorithm from screening to confirmation. However, other agencies have recently adopted the reverse testing algorithm which has outperformed the traditional algorithm in certain populations. We finally focus on syphilotherapy and monitoring response to treatment with a specific emphasis on pregnancy. Birth Defects Research 109:347-352, 2017. © 2017 Wiley Periodicals, Inc.

Re-evaluating the sensitivity of the rabbit infectivity test for Treponema pallidum in modern era

BACKGROUND

The rabbit infectivity test (RIT) was previously described as a highly-sensitive method for clinically detecting Treponema pallidum. But our primary study indicated this result may have changed in current antibiotics era.

METHODS

By inoculating rabbits testis with cerebrospinal fluid (CSF) (n=63) and exudate from hard chancre lesions (n=13), we re-evaluated the sensitivity of RIT in modern era. All isolated T. pallidum strains from the RIT were performed for the strain type based on "CDC subtype/tp0548" method. Chi-square and Fisher's exact tests were used to determine the statistical significance of differences across data sets.

RESULTS

Result indicated that 2 of 63 CSF (2/63, 3.17%) and 5 of 13 lesion exudate samples (5/13, 38.47%) were positive in the RIT, with a much longer time to detection for CSF samples. Only 1 of 28 samples from patients who admitted treatment with antibiotics prior to clinical exam was positive in the RIT; while 6 of 48 patients, who admitted no recent exposure to antibiotics or was unclear about the medical history, were positive in RIT. DNA sequence analysis revealed 6 strains of 14d/f subtype and one strain of 14a/f subtype.

CONCLUSIONS

In conclusions, RIT is no longer a highly sensitive method for detecting T. pallidum in clinical samples as before, and is not inadequately considered to be a reference method for measuring the sensitivity of other new methods, such as the PCR. These data represent the first reexamination of the sensitivity of RIT in the post-antibiotic era with a large clinical sample.

Return of the Great Pox

Syphilis is on the increase globally. While recognized more frequently in patients with, HIV/AIDS, it is not unusual among immune competent individuals sometimes presenting with unusual manifestations and/or behaviour. This paper reviews the history and clinical features of syphilis and draws attention to the oral manifestations. CPD/Clinical Relevance: Syphilis should be in the differential diagnosis of oral ulcers or unusual oral lesions.

The clinical spectrum of syphilitic balanitis of Follmann: report of five cases and a review of the literature

BACKGROUND

Eugène Follmann first described syphilitic balanitis as a manifestation of primary syphilis in 1948 and since then it has been known as syphilitic balanitis of Follmann (SBF). So far, SBF has rarely been described in literature.

OBJECTIVES

We are reporting five additional cases of SBF considering the broad differential diagnosis of balanitis.

METHODS

A review of the available literature of SBF was performed and five additional cases analyzed.

RESULTS

In our case series, the clinical appearance of SBF shows a heterogeneous spectrum varying from painful oedematous balanoposthitis with beginning paraphimosis to superficial erosive balanitis and even to painless induration of the glans.

CONCLUSIONS

SBF might be seen more frequently than has been described due to misinterpretation. Therefore primary syphilis should be included in the differential diagnosis of balanitis and balanoposthitis.

Painful and multiple anogenital lesions are common in men with Treponema pallidum PCR-positive primary syphilis without herpes simplex virus coinfection: a cross-sectional clinic-based study

BACKGROUND

Chancres, the hallmark of primary syphilis, are classically described as single, painless ulcers at the site of Treponema pallidum inoculation. We aimed to determine the frequency of painful or multiple anogenital lesions of primary syphilis among men, whether there was concurrent herpes simplex virus (HSV) infection and whether HIV status altered clinical presentations.

METHODS

This study was conducted among men with T. pallidum PCR-positive lesions, attending a clinic in Melbourne, Australia, between 2009 and 2014. Lesions were also tested with HSV PCR, and syphilis serology undertaken.

RESULTS

183 men with T. pallidum PCR-positive primary anogenital lesions were included. 89% were men who have sex with men, and 10.9% were heterosexual. 38 men (20.8%) were HIV positive. Anal lesions were more common in HIV-positive men (34.2%) than in HIV-negative men (11.6%). Primary lesions were frequently painful (49.2%) or multiple (37.7%), and infrequently associated with HSV (2.7%). Of 37 men with both painful and multiple primary lesions, only 8% had concurrent HSV. Presentation was not significantly altered by HIV status.

CONCLUSIONS

Primary syphilis lesions are often painful and/or multiple in the absence of herpes coinfection, and may be clinically misdiagnosed.

Comparison of Diagnostic Accuracy of PCR Targeting the 47-Kilodalton Protein Membrane Gene of Treponema pallidum and PCR Targeting the DNA Polymerase I Gene: Systematic Review and Meta-analysis

Treponema pallidum PCR (Tp-PCR) testing now is recommended as a valid tool for the diagnosis of primary or secondary syphilis. The objectives were to systematically review and determine the optimal specific target gene to be used for Tp-PCR. Comparisons of the performance of the two main targets are tpp47 and polA genes were done using meta-analysis. Three electronic bibliographic databases, representing abstract books from five conferences specialized in infectious diseases from January 1990 to March 2015, were searched. Search keywords included ("syphilis" OR "Treponema pallidum" OR "neurosyphilis") AND ("PCR" OR "PCR" OR "molecular amplification"). We included diagnostic studies assessing the performance of Tp-PCR targeting tpp47 (tpp47-Tp-PCR) or the polA gene (polA-Tp-PCR) in ulcers from early syphilis. All studies were assessed against quality criteria using the QUADAS-2 tool. Of 37 studies identified, 62.2% were judged at low risk of bias or applicability. Most used the U.S. Centers for Disease Control and Prevention (CDC) case definitions for primary or secondary (early) syphilis (89.2%; n = 33); 15 (40.5%) used darkfield microscopy (DFM). We did not find differences in sensitivity and specificity between the two Tp-PCR methods in the subgroup of studies using adequate reference tests. Among studies using DFM as the reference test, sensitivities were 79.8% (95% confidence intervals [CI], 72.7 to 85.4%) and 71.4% (46.0 to 88.0%) for tpp47-Tp-PCR and polA-Tp-PCR (P = 0.217), respectively; respective specificities were 95.3% (93.5 to 96.6%) and 93.7% (91.8 to 95.2%) (P = 0.304). Our findings suggest that the two Tp-PCR methods have similar accuracy and could be used interchangeably.

Emerging trends and persistent challenges in the management of adult syphilis

There are an estimated 10.6 million incident cases of syphilis worldwide each year. We highlight some persistent challenges and emerging trends in the clinical management of syphilis with a particular focus on therapy, serology, diagnostics, and prevention. Decades after the introduction of penicillin, the optimal management of early syphilis continues to be a controversial topic, particularly in the setting of HIV co-infection. Similarly, the need for routine lumbar puncture in HIV co-infected asymptomatic persons is an unanswered question. Despite advances in both automation and point-of-care diagnostics, we continue to rely on indirect measures of disease activity to manage this infection. As syphilis rates in some populations continue to rise, novel and effective prevention strategies are needed.

Performance of the 47-kilodalton membrane protein versus DNA polymerase I genes for detection of Treponema pallidum by PCR in ulcers

Treponema pallidum PCR (Tp-PCR) is a direct diagnostic method for primary and secondary syphilis, but there is no recommendation regarding the best choice of target gene. In this study, we sequentially tested 272 specimens from patients with sexually transmitted ulcers using Tp-PCR targeting the tpp47 and then polA genes. The two methods showed similar accuracies and an almost-perfect agreement.

Treatment and outcomes of polymerase chain reaction-confirmed early syphilis

Background Syphilis is resurgent among gay and bisexual men (GBM) despite effective treatment and widely available diagnostic serology. The polymerase chain reaction assay for Treponema pallidum (TP-PCR) is available, but little is known about the clinical features and outcomes for patients testing positive by TP-PCR.

METHODS

Clinical data were collected from four medical practices for patients recording a positive TP-PCR result between 2004 and 2011. Demographic, serological, treatment and reinfection details were obtained. Results were stratified by HIV status and whether treatment conformed to international guidelines.

RESULTS

220 patients were positive for TP-PCR, of whom 92% were GBM. Seventeen (8.1%) were positive by TP-PCR before seroconversion. Almost one-third (32.1%) received treatment beyond that recommended in guidelines, and this was associated with HIV status (40.3% HIV positive vs 22.4% HIV negative, P<0.01). All but one patient with adequate follow up achieved serological cure. There was no significant difference in time to serological cure between the groups receiving standard therapy or enhanced therapy (95 vs 108 days; P=0.67) or between HIV positive and negative patients (93 vs 104 days, P=0.06). Nineteen patients were reinfected during follow up.

CONCLUSION

TP-PCR aids early diagnosis of syphilis and may be reactive before conventional serological tests. Treatment outcomes for TP-PCR-positive early infection were excellent, but a significant proportion of patients received non-standard therapy. Expanded use of syphilis PCR testing in at-risk populations is recommended since early identification and treatment is likely to be important in controlling the current epidemic in GBM.