Assessment of a real-time PCR test to diagnose syphilis from diverse biological samples

First Report of Genetic Resistance to Azithromycin in Treponema pallidum from Blood Samples Among Men Who Have Sex with Men and People Living with HIV from Mexico

Syphilis is a re-emerging sexually transmitted disease caused by Treponema pallidum subsp. pallidum (TPA). It especially affects vulnerable populations such as men who have sex with men (MSM) and people living with HIV. Despite being treatable with benzathine penicillin G, a substantial increase in TPA resistance to azithromycin has been reported in many countries. The objective of this study was to detect the resistance of T. pallidum (TPA) to macrolides in blood samples from men who have sex with men and people living with HIV using molecular methods in a cross-sectional study. The detection of both TPA and the resistance to azithromycin was achieved through molecular methodologies (nested PCR), which were applied to blood samples of people with asymptomatic syphilis. We report the first data on the molecular prevalence of TPA and the first identification of genetic resistance to azithromycin (punctual mutation A2058G) in Mexico. Resistance testing for syphilis is not routinely performed in Mexico, but azithromycin continues to be prescribed despite syphilis being treatable with benzathine penicillin G. Therefore, the surveillance of cases of syphilis treatment failure, especially in vulnerable populations, which are the population group that maintains the active transmission of TPA, is recommended.

Prospective evaluation of non-invasive saliva specimens for the diagnosis of syphilis and molecular surveillance of Treponema pallidum

The promising diagnostic performance of molecular testing for syphilis using saliva and urine samples has been reported; however, further evaluation of its possible application for diagnosis and molecular surveillance is required. In addition, the development of a rapid and easy-to-perform molecular test for syphilis is important for its use in the clinical setting. We comprehensively evaluated the diagnostic and surveillance performance of two novel loop-mediated isothermal amplification (LAMP) assays using saliva and urine samples. Saliva, urine, and whole blood were collected from patients who underwent serological testing for syphilis at outpatient clinics. Treponema pallidum DNA in specimens was detected using quantitative PCR (qPCR), nested PCR, and novel LAMP assays. T. pallidum genotyping was conducted by multi-locus sequence typing (MLST). Of the 163 patients recruited, 98 were diagnosed with syphilis (primary: n = 35; secondary: n = 40; latent: n = 23). qPCR showed the highest sensitivity among the molecular tests performed with a sensitivity of 54.1% and 30.3% for all syphilis patients using saliva and urine samples, respectively. A novel method of LAMP combined with dry reagents and crude DNA extraction (Dry-LAMP) showed a probit detection limit of 37.4 copies/reaction within 45 min. The agreement rate between Dry-LAMP and qPCR for saliva was 95.7% (κ coefficient 0.90). The T. pallidum genotype was identified in 48 patients by MLST using saliva samples. Molecular analysis of saliva could be used as a supplementary diagnostic test for syphilis and molecular surveillance of the T. pallidum genotype. Dry-LAMP is expected to be helpful in the clinical diagnosis of syphilis.

A case for implementing an HSV1/2, VZV, and syphilis lesion panel in Manitoba, Canada

Syphilis, caused by Treponema pallidum subsp. pallidum (TPA), is becoming a significant public health concern, with rising incidence in Manitoba exceeding the national average. The province has also seen a demographic shift leading to women representing 51.9% of cases in 2021, leading to the re-emergence of congenital syphilis. Given the similarities in lesion appearance between TPA and other pathogens such as herpesviruses, accurate diagnosis is crucial for effective management and prevention. In order to address the potential for missed TPA cases, we conducted a quality assurance study from June 2021 to March 2023, screening over 5,000 mucocutaneous lesion swabs for TPA, initially submitted for herpes simplex virus (HSV) and varicella zoster virus (VZV) testing. Positivity rates were 13% for HSV1, 13% for HSV2, 6.7% for VZV, and 6.6% for TPA. Turnaround times (TAT) for TPA testing, as a send-out to the reference laboratory, averaged 17.8 days. Of the TPA-positive specimens, 36% did not have a corresponding TPA PCR test ordered, and 19% did not have accompanying syphilis serology within 30 days of collection. Creation of a multiplex lesion panel identified high sensitivity and specificity for HSV1, HSV2, VZV, and TPA, with robust reproducibility across multiple runs. Incorporation of TPA into a lesion panel improved the TAT to 4 days. Our findings emphasize the need for improved testing strategies to combat the syphilis epidemic and enhance public health outcomes.IMPORTANCESyphilis resurgence has become a significant global public health concern. In particular, the Canadian Prairies have been struggling with high incidence since 2016, exceeding the national Canadian average. We undertook a quality assurance study that highlighted significant gaps in diagnosis of acute syphilis, which led to the development of a highly sensitive and specific multiplex lesion assay for the dual detection of herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2 (HSV-2), varicella zoster virus (VZV), and syphilis.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

CDC Laboratory Recommendations for Syphilis Testing, United States, 2024

This report provides new CDC recommendations for tests that can support a diagnosis of syphilis, including serologic testing and methods for the identification of the causative agent Treponema pallidum. These comprehensive recommendations are the first published by CDC on laboratory testing for syphilis, which has traditionally been based on serologic algorithms to detect a humoral immune response to T. pallidum. These tests can be divided into nontreponemal and treponemal tests depending on whether they detect antibodies that are broadly reactive to lipoidal antigens shared by both host and T. pallidum or antibodies specific to T. pallidum, respectively. Both types of tests must be used in conjunction to help distinguish between an untreated infection or a past infection that has been successfully treated. Newer serologic tests allow for laboratory automation but must be used in an algorithm, which also can involve older manual serologic tests. Direct detection of T. pallidum continues to evolve from microscopic examination of material from lesions for visualization of T. pallidum to molecular detection of the organism. Limited point-of-care tests for syphilis are available in the United States; increased availability of point-of-care tests that are sensitive and specific could facilitate expansion of screening programs and reduce the time from test result to treatment. These recommendations are intended for use by clinical laboratory directors, laboratory staff, clinicians, and disease control personnel who must choose among the multiple available testing methods, establish standard operating procedures for collecting and processing specimens, interpret test results for laboratory reporting, and counsel and treat patients. Future revisions to these recommendations will be based on new research or technologic advancements for syphilis clinical laboratory science.

Treponema pallidum Detection at Asymptomatic Oral, Anal, and Vaginal Sites in Adults Reporting Sexual Contact with Persons with Syphilis

We investigated Treponema pallidum PCR positivity at mucosal sites (oral, anal, and vaginal sites) among adults who had sexual contact with a person with syphilis (syphilis contacts). All syphilis contacts had oral rinse and swab samples collected for testing. Men who have sex with men had anal swab and women had vaginal swab samples collected for testing, regardless of the presence of lesions. Of 407 persons tested, 42 (10%) had early syphilis diagnosed; of those, 19 (45%) tested positive by PCR from any anatomic site and had a positive serologic test. T. pallidum was positive from vaginal samples in 3 women, anal samples in 3 men, and oral cavity samples in 2 women and 3 men, without symptoms at those sites. Three women had no prior syphilis serologic test. T. pallidum detection at asymptomatic mucosal sites suggests early syphilis infections, particularly in cases that would conventionally be staged as latent syphilis of unknown duration.

Treponema pallidum PCR screening at mucosal sites of asymptomatic men who have sex with men taking HIV pre-exposure prophylaxis

Early detection and treatment of syphilis will reduce the infectious period and transmission. We aimed to determine whether screening men who have sex with men (MSM) taking HIV pre-exposure prophylaxis (PrEP) for syphilis using Treponema pallidum polymerase chain reaction (PCR) could detect syphilis before the appearance of syphilis antibodies in serology. MSM attending 3-monthly PrEP clinic visits in Melbourne, Australia, were screened with a PCR assay targeting the polA gene of T. pallidum from an anal swab and an oral rinse between November 2019 and March 2020. Participants were serologically screened for syphilis using chemiluminescence immunoassay. A total of 309 asymptomatic participants provided an anal swab and oral rinse sample for T. pallidum PCR screening. Two syphilis cases (0.6%) were detected: one man had a positive serology only; another man had T. pallidum detected by PCR from an anal swab and a positive serology. PCR positivity was 0.3% (n = 1) for anal swabs and 0% (n = 0) for oral rinse. In this study, T. pallidum PCR screening at routine PrEP clinic visits did not identify additional cases of early syphilis over serological screening performed at these visits. IMPORTANCE With the ongoing syphilis epidemic in men who have sex with men (MSM), we investigated the role of using Treponema pallidum polymerase chain reaction (PCR) testing at the oral cavity and anus in MSM taking pre-exposure prophylaxis for the early detection of syphilis. We evaluated whether the PCR tests from these mucosal sites can detect syphilis infection early, before the development of syphilis antibodies in serology. Our study found two syphilis cases among 309 MSM, and only one syphilis case had a positive anal PCR swab, although serology was positive. We conclude that additional PCR testing is likely to be expensive and would not be cost effective for individuals who regularly screen for syphilis. However, future studies with a larger sample size are required.

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.

Red Blood Cell Lysis Pretreatment Can Significantly Improve the Yield of Treponema pallidum DNA from Blood

PCR can be a supplement to Treponema serological testing. However, its sensitivity is not satisfactory for blood sample testing. The aim of this study was to investigate whether pretreatment with red blood cell (RBC) lysis could enhance the yield of Treponema pallidum subsp. pallidum DNA extraction from blood. We developed and verified the efficacy of a quantitative PCR (qPCR) assay that utilizes TaqMan technology to specifically detect T. pallidum DNA by targeting the polA gene. Simulation media with 106 to 100 treponemes/mL were prepared in normal saline (NS), whole blood, plasma, and serum, and RBC lysis pretreatment was performed on a portion of whole blood. Then, blood samples drawn from 50 syphilitic rabbits were divided in parallel into five groups, labeled whole blood, whole blood/lysed RBCs, plasma, serum, and blood cells/lysed RBCs. DNA extraction and qPCR detection were performed. The detection rate and copy number were compared among different groups. The polA assay showed good linearity and an excellent amplification efficiency of 102%. In the simulated blood samples, the detection limit of the polA assay reached 1 × 102 treponemes/mL in whole blood/lysed RBCs, plasma, and serum. However, the detection limit was only 1 × 104 treponemes/mL in NS and whole blood. Among the blood samples from syphilitic rabbits, whole blood/lysed RBCs showed the best detection rate (82.0%), while the detection rate for whole blood was only 6%. The copy number of whole blood/lysed RBCs was higher than that of whole blood. RBC lysis pretreatment can significantly improve the yield of T. pallidum DNA from whole blood, and the yield is better than that from whole blood, plasma, serum, and blood cells/lysed RBCs. IMPORTANCE Syphilis is a sexually transmitted disease caused by T. pallidum that can spread into the blood. T. pallidum DNA can be detected in blood by PCR but with low sensitivity. Few studies have applied RBC lysis pretreatment to blood T. pallidum DNA extraction. This study shows that the detection limit, detection rate, and copy number of whole blood/lysed RBCs were better than those of whole blood, plasma, and serum. After RBC lysis pretreatment, the yield of low concentrations of T. pallidum DNA was improved, and the low sensitivity of blood-based T. pallidum PCR was improved. Therefore, whole blood/lysed RBCs are the ideal sample for acquiring blood T. pallidum DNA.

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.

Performance of Molecular Tests in the Diagnosis of Syphilis From 2009 to 2019: A Systematic Review and Meta-Analysis

BACKGROUND

Syphilis continues to be a public health problem, and its diagnosis still has limitations. Molecular diagnosis provides an alternative for rapid and effective management. The objective is to determine the accuracy of tests in the molecular diagnosis of syphilis.

METHODS

We searched PubMed and Web of Sciences for articles related to molecular detection of syphilis from January 1, 2009, to December 31, 2019. The bivariate Reitsma model and the hierarchical receiver operating characteristic curve model were used to evaluate the diagnostic performance of molecular tests at a 95% confidence interval. A subgroup meta-analysis was performed to explore sources of heterogeneity.

RESULTS

Forty-seven articles were identified for qualitative synthesis, of which 23 met the inclusion criteria for meta-analysis. The pooled sensitivities in conventional polymerase chain reaction (PCR) and real-time PCR were 77.52 (59.50-89.01) and 68.43 (54.96-79.39), respectively. The pooled specificities were 98.00 (90.73-99.59) and 98.84 (97.55-99.46), respectively. Ulcer samples had a better performance (sensitivity of 79.88 [69.00-87.62] and specificity of 98.58 [97.25-99.27]), and the major target genes were the polymerase A gene and tpp47 gene.

CONCLUSIONS

Our work showed that conventional PCR was more widely used than real-time PCR in the diagnosis of syphilis, and ulcers were the best specimens. Sample types and target genes are factors that may influence the quality of the different tests. These results could provide evidence for further work in the direction of providing a more efficient diagnostic test.

Quantified Detection of Treponema pallidum DNA by PCR Assays in Urine and Plasma of Syphilis Patients

Treponema pallidum can invade any organ, and T. pallidum DNA can be detected in various tissues and fluids. However, the knowledge of the presence and loads of T. pallidum DNA in urine is limited. For this study, we enrolled 208 syphilis patients (34 primary syphilis, 61 secondary syphilis, 68 latent syphilis, and 45 symptomatic neurosyphilis) and collected urine and plasma samples from them. polA and Tpp47 genes were amplified in urine supernatant, urine sediment, and plasma using nested PCR and droplet digital PCR assays. The detection rates were 14.9% (31 of 208) and 24.2% (50 of 207) in urine supernatant and sediment, respectively (P = 0.017). The detection rates of T. pallidum DNA in urine sediment were 47.1, 47.5, 4.4, and 4.5% for primary, secondary, latent, and symptomatic neurosyphilis, respectively. After treatment, T. pallidum DNA in urine in 20 syphilis patients turned negative. Loads of T. pallidum DNA in urine sediment were significantly higher than those in plasma and urine supernatant (both P < 0.05). Our study indicated that T. pallidum DNA in urine could be found in patients at all stages of syphilis and showed high loads in urine sediment. Though it is unlikely to improve the routine diagnostic algorithm, the detection of T. pallidum DNA in urine may play certain roles in cases difficult to diagnose. In addition, urine is abundant and convenient to collect; therefore, urine sediment could be an ideal specimen for acquiring an amount of T. pallidum DNA that can be supplement samples for the detection of molecular typing of T. pallidum.

IMPORTANCE Syphilis is a sexually transmitted disease caused by Treponema pallidum sub. pallidum.T. pallidum can invade many organs, and T. pallidum DNA can be detected in various tissues and fluids. The results reported here demonstrated that T. pallidum DNA could be detected in urine in patients at all stages of syphilis. The detection rate and loads of T. pallidum DNA in urine sediment were significantly higher than those in urine supernatant. Urine is abundant, and its collection is noninvasive and convenient; therefore, urine is an ideal sample for acquiring a large amount of T. pallidum DNA, which can be supplement samples for the detection of molecular typing of T. pallidum.

Intrathecal Synthesis Index of Specific Anti-Treponema IgG: a New Tool for the Diagnosis of Neurosyphilis

Neurosyphilis (NS) diagnosis is challenging because clinical signs are diverse and unspecific, and a sensitive and specific laboratory test is lacking. We tested the performance of an antibody index (AI) for intrathecal synthesis of specific anti-Treponema IgG by enzyme-linked immunosorbent assay (ELISA) for NS diagnosis. We conducted a retroprospective monocentric study including adults with neurological symptoms who had serum and cerebral spinal fluid (CSF) samples collected between 2006 and 2021. Two NS definitions were used. NS1 included patients with neurological symptoms, positive Treponema pallidum particle agglutination (TPPA) serology, and CSF-TPPA of ≥320, as well as CSF-leukocytes of >5 cells/mm³ and/or CSF-protein of >0.45 g/L and/or a reactive CSF-VDRL/RPR test. NS2 included patients with acute ocular and/or otologic symptoms, positive TPPA serology, and a response to NS treatment. Controls were patients with central nervous system disorders other than neurosyphilis. Anti-Treponema pallidum IgG were measured simultaneously in serum and CSF, and AI was calculated according to Reiber diagram. We assessed the AI test area under the curve (AUC), sensitivity/specificity, and estimated positive and negative predictive values. In total, 16 NS1 patients, 11 NS2 patients, and 71 controls were included. With an AI of ≥1.7 as a positive test for NS diagnostic, specificity was 98.6% (95% confidence interval [CI 95%] of 92.4 to 100.0) and sensitivity was 81.3% (CI 95% of 54.4 to 96.0) for NS1 and 98.6% (CI 95% 92.4 to 100.0) and 27.3% (CI 95% 6.0 to 61.0), respectively, for NS2. Positive and negative predictive values were >95% for NS1 and >85% for NS2, for prevalence above and below 20%. Measuring an AI for intrathecal synthesis of specific anti-Treponema pallidum IgG is a new promising tool highly specific for NS diagnosis.

IMPORTANCE In the context of a lack of a gold standard for the diagnosis of neurosyphilis due to either nonspecific or nonsensitive tests, we present in this article a new promising tool highly specific for NS diagnosis. This new test involves measuring an intrathecal synthesis index of specific anti-Treponema IgG by ELISA.

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.

Detection A2058G and A2059G on the 23S rRNA Gene by Multiplex Nested PCR to Identify Treponema pallidum Resistance to Azithromycin in Indonesia

Azithromycin is one of the antibiotics used to treat syphilis, especially in the context of penicillin allergy. Resistance to azithromycin is widely reported associated with one and/or two point mutations on the 23S rRNA gene but has yet to be described in Indonesia. Specimens were collected from 220 patients diagnosed with secondary syphilis. A multiplex nested PCR testing system using the 23S rRNA target gene of Treponema pallidum was designed using three pairs of primers. The first step used PCR pairs of primers to detect T. pallidum. In the second step of PCR using 2 pairs of primers were achieved to identify azithromycin resistant T. pallidum based on A2058G and A2059G point mutations. There was no T.pallidum identified resistant to azithromycin in Jakarta and Bandung. T. pallidum resistance to azithromycin were found in Makassar, Medan, and Bali. The majority of azithromycin resistance was found among heterosexual males and in patients living with HIV. This study has demonstrated T. pallidum resistance to azithromycin in Indonesia appears to be a novel variant of resistance, containing both the A2058G and A2059G mutations that was found in Medan and Makassar.

Analysis of DNA extraction methods for detection of Treponema pallidum: A comparison of three methods

Syphilis is a sexually transmitted disease caused by Treponema pallidum. DNA amplification methods have started to be used to facilitate diagnosis at different stages of the disease. The success of such methodologies depends on obtaining DNA from clinical samples in adequate quantity and quality for molecular reactions. There are many DNA extraction kits, but often the molecular analysis process is unfeasible due to its cost and access to imported products. Thus, this study aimed to analyze three methods of extracting DNA from Treponema pallidum from ulcers of patients investigated for syphilis. The three methods, an in house one (sonication) and two commercial ones (LGC, Brazil) and the PureLink Genomic DNA Mini Kit (Thermo Fisher Scientific, USA) were compared to the sequencing of these samples, which were used as a reference. Each method was evaluated based on the detection of T. pallidum by PCR using the tpp47 gene as a target for amplification, DNA quantification and method execution time. When compared to the sequencing, the sensitivity and agreement of the PureLink, sonication and LGC methods to extracted DNA were 100% (K = 1.0), 96.5% (K = 0.96) and 72.4% (K = 0.694), respectively. Specificity was 100% with the three methods. The sonication method was the closest in concentration of DNA to the PureLink method with a similar degree of purity, besides having the lowest cost-benefit ratio. It can be an interesting option for laboratories that work with reduced costs, since it is much more financially viable.

Multilocus sequence typing of Treponema pallidum subsp. pallidum in Barcelona

Aim: To implement the multilocus sequence typing (MLST) methodology in syphilis samples previously characterized by enhanced CDC typing (ECDCT) and macrolide resistance. Materials & methods: MLST was performed on genital ulcer and blood samples by analyzing a region of the tp0136, tp0548 and tp0705 loci using Sanger sequencing. Results: Up to 59/85 (69.4%) of genital ulcer and 4/39 (10.3%) of whole blood samples were fully typed. The most frequent profiles were 1.3.1 (56%) and 1.1.1 (11%). All the 1.3.1 samples typed carried the A2058G mutation, responsible for macrolide resistance. MLST and ECDCT showed similar overall typing yields. Conclusion: Several allelic profiles of T. pallidum subsp. pallidum were identified and classified into two major genetic clades in Barcelona. Our results were similar to that described in Europe.

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.

Treponema pallidum detection in lesion and non-lesion sites in men who have sex with men with early syphilis: a prospective, cross-sectional study

BACKGROUND

Syphilis transmission is increasing, and precisely how Treponema pallidum is transmitted sexually from person to person is unclear. We aimed to determine the frequency of T pallidum shedding from potentially asymptomatic sites and the stage of infection at which shedding is most frequent in men who have sex with men (MSM), who have been disproportionately affected by syphilis.

METHODS

We did a prospective, cross-sectional study in MSM recruited from Melbourne Sexual Health Centre (Melbourne, VIC, Australia). Men were eligible if they were aged 18 years or older, reported sex with men during the past 12 months, and had laboratory confirmed primary, secondary, or early latent syphilis, consistent with Australian definitions. Primary and secondary syphilis lesions were swabbed and non-lesion samples were collected via oral rinse, oral cavity swab, anal canal swab, urine, and semen. Samples were tested for T pallidum using PCR assays targeting polA (lesion and non-lesion samples) and 47 kDa (non-lesion samples only) gene targets. The primary outcome was the proportion of men with T pallidum detected from potentially asymptomatic sites-namely, the mouth, anus, urethra, and semen.

FINDINGS

Between Nov 30, 2015, and May 23, 2019, 246 MSM were screened for inclusion, of whom 200 had serologically confirmed early syphilis and were included in the study: 54 (27%) of 200 had primary syphilis, 93 (47%) had secondary syphilis, and 53 (27%) had early latent syphilis. T pallidum DNA was detected in 48 (24%; 95% CI 18·3-30·5) of 200 men by oral rinse or oral lesion swab, or both, of whom 24 had no oral lesions. Oral T pallidum detection was most frequent in those with secondary syphilis compared with those at other stages of disease (41 [44%] of 93 vs seven [7%] of 107; p<0·0001), and in men with rapid plasma reagin titres of 1/64 or higher compared with those with lower titres (37 [32%] of 117 vs 11 [13%] of 83; p=0·0026). T pallidum was detected by anal canal swab or anal lesion swab, or both, in 45 (23·0%; 95% CI 17·3-29·5) of 196 men with available samples, of whom ten had no anal lesion. Furthermore, T pallidum was detected in urine samples of 12 (6·1%, 3·2-10·3) of 198 men and in semen samples from six (12·0%, 4·5-24·3) of 50 men who provided samples. Among the 93 men with secondary syphilis, 69 (74%) had T pallidum detected at any site, and 24 (26%) had detection at two or more separate sites. Among the 54 men with primary syphilis, 49 (91%) had T pallidum detected at any site, and 11 (20%) had detection at two or more separate sites. Among the 53 men with early latent syphilis, four (8%) had T pallidum detected at any site and none had T pallidum detected at two or more separate sites.

INTERPRETATION

Unrecognised oral and anal shedding of T pallidum occurs in MSM with early syphilis, most frequently in those with secondary syphilis, suggesting secondary syphilis is the most infectious stage and that earlier detection and treatment of syphilis to prevent progression to the secondary stage might improve syphilis control. Future research is needed to ascertain the contribution of shedding of T pallidum from non-lesion sites to transmission of syphilis.

FUNDING

Australian National Health and Medical Research Council.

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.

Male urethritis. A review of the ideal diagnostic method

Male urethritis is an inflammation of the urethra and the periurethral glands; it is widely classified as gonococcal or non-gonococcal. The most frequent microorganisms responsible are Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma urealyticum, and Ureaplasma parvum. In the last three decades, the diagnosis of sexually transmitted diseases depended almost exclusively on traditional methods, such as culture, enzyme immunoassay, fluorescent antibody staining, and hybridization, until the appearance of molecular techniques. Clinical syndromes such as urethritis are rarely specific for a single microorganism, so screening strategies should allow multiple agents to be considered. Multiplex PCR is the fastest and most sensitive technique for the diagnosis of gonococcal and non-gonococcal urethritis. Male urethritis without treatment is one of the main health problems related to reproductive and sexual function, constituting one of the main causes of infertility. The objective of this mini-review was to analyze the epidemiology, causes, diagnosis, and complications of male urethritis.

A retrospective study on nested PCR detection of syphilis treponemes in clinical samples: PCR detection contributes to the diagnosis of syphilis in patients with seronegative and serodiscrepant results

Syphilis, caused by Treponema pallidum ssp. pallidum (TPA), is a persisting global health problem. Although syphilis diagnostics relies mainly on serology, serological tests have some limitations, and it is recommended that the final diagnosis be supported by additional tests. The purpose of this study was to analyze the relationship between serology and PCR in syphilis diagnostics. From the year 2004 to May 2019, a total of 941 samples were taken from 833 patients suspected of having syphilis, in Czech Republic. In all these samples, both nested PCR detection of TPA and serology testing were performed. Of the 941 samples, 126 were seronegative, 651 were seropositive, and 164 were serodiscrepant. Among seronegative samples (n = 126), 11 were PCR-positive (8.7%). Among seropositive samples (n = 651; i.e., samples positive for both non-treponemal and treponemal serology tests), 368 samples were PCR-positive (56.5%). The remaining 164 serodiscrepant samples included RPR negative and treponemal serological test-positive samples (n = 154) and a set of 10 RPR-positive samples negative in treponemal serological tests. While the first group revealed 73 PCR-positive samples (47.4%), the second revealed 5 PCR positive samples (50.0%). PCR detection rates were highest in primary syphilis, with lower rates in the secondary and undetermined syphilis stages. As shown here, the nested PCR can improve diagnostics of syphilis, especially in seronegative patients and in patients with discrepant serology.

Prevalence and associated factors of Treponema pallidum infection in a rural area of southwestern China

Background

Epidemiological data on Treponema pallidum infection are scarce from the southwestern region of China. The purpose of this study was to determine the distribution and determinants of T. pallidum infection in the region.

Methods

A community-based cross-sectional study of 2608 participants aged ≥14 years was conducted in a rural area of southwestern China in 2014–15. A pretested questionnaire was used to collect sociodemographic characteristics and other factors associated with T. pallidum infection. The diagnoses of T. pallidum, human immunodeficiency virus (HIV), hepatitis B virus (HBV) and hepatitis C virus (HCV) infections were determined by commercial test kits. Logistic regression analysis was used to determine the correlates for T. pallidum infection, and adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were calculated.

Results

The prevalence of T. pallidum infection was 1.2% (95% CI 0.8 to 1.7%). Risk factors varied by gender. In the male group, T. pallidum infection was significantly associated with ever injection drug use (aOR = 9.42, 95% CI 2.47 to 35.87) and HCV infection (aOR = 13.28, 95% CI 3.20 to 51.70). In the female group, correlates for T. pallidum infection included spouse having syphilis (aOR = 126.66, 95% CI 7.58 to 2122.94), ever having blood transfusion (aOR = 10.51, 95% CI 1.58 to 41.21) and HBV infection (aOR = 4.19, 95% CI 1.35 to 10.93).

Conclusions

The prevalence of T. pallidum infection was high in the rural area of southwestern China. Correlates for T. pallidum infection varied with sex specific. Intervention should be developed for the prevention and control of T. pallidum infection.

A Novel Nested Real-time Polymerase Chain Reaction for Treponema pallidum DNA in Syphilis Biospecimens

BACKGROUND

Early diagnosis of Treponema pallidum infection is helpful for disease management, and conventional PCR is suitable for lesion swabs of patients with probable early syphilis. We thus tested nested and real-time PCR (NR-PCR) in various biosamples from syphilitic patients.

METHODS

Samples were collected from syphilis patients before treatment. Specific primer sequences targeting the T. pallidum gene polA were designed for NR-PCR.

RESULTS

Across syphilis types, most samples assayed with NR-PCR returned a positive result, including earlobe blood (92.0%), cerebrospinal fluid (CSF) (90.2%), lesion swabs (74.3%), serum (66.9%), and whole blood (64.2%). No significant differences were observed in positive samples for whole blood, serum, and lesion swabs between primary and secondary syphilis (P > 0.05 for all comparisons). However, more whole-blood samples from patients with secondary syphilis were positive for NR-PCR than whole blood samples from patients with tertiary and latent syphilis (P < 0.05 for all comparisons). For neurosyphilis patients, significantly more earlobe blood samples tested positive than did whole-blood samples (P < 0.05), but there was no difference in positive results for earlobe blood and whole blood in latent syphilis. Significantly more serum samples tested positive in latent syphilis patients with rapid plasma regain (RPR) titers of 1:8 or greater, compared to those with RPR of 1:4 or less.

CONCLUSIONS

Nested and real-time PCR can be used to identify T. pallidum DNA in biosamples from syphilitic patients, especially earlobe blood.

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.

Molecular characterization of Treponema pallidum subsp. pallidum in Switzerland and France with a new multilocus sequence typing scheme

Syphilis is an important public health problem and an increasing incidence has been noted in recent years. Characterization of strain diversity through molecular data plays a critical role in the epidemiological understanding of this re-emergence. We here propose a new high-resolution multilocus sequence typing (MLST) scheme for Treponema pallidum subsp. pallidum (TPA). We analyzed 30 complete and draft TPA genomes obtained directly from clinical samples or from rabbit propagated strains to identify suitable typing loci and tested the new scheme on 120 clinical samples collected in Switzerland and France. Our analyses yielded three loci with high discriminatory power: TP0136, TP0548, and TP0705. Together with analysis of the 23S rRNA gene mutations for macrolide resistance, we propose these loci as MLST for TPA. Among clinical samples, 23 allelic profiles as well as a high percentage (80% samples) of macrolide resistance were revealed. The new MLST has higher discriminatory power compared to previous typing schemes, enabling distinction of TPA from other treponemal bacteria, distinction between the two main TPA clades (Nichols and SS14), and differentiation of strains within these clades.

Assessing effects of different processing procedures on the yield of Treponema pallidum DNA from blood

In this work, we employed real-time PCR analysis targeting tp0574 to investigate the effects of different processing procedures on the yield of T. pallidum DNA from blood to improve assay sensitivity. The T. pallidum DNA yields following red blood cell lysis pretreatment were 40.4 times greater from whole blood and 32.4 times greater from residual hematocytes than yields without pretreatment. For the simulated whole-blood experiments, the T. pallidum DNA yields from the lower layer were 2.8, 4.6, 7.3, 12.6, 15.24, 16.7, 65.1 and 73.1 times those from the upper layer following centrifugation at 500×, 1000×, 2000×, 4000×, 5000×, 7000×, 10,000× and 20,000 × g, respectively. However, the T. pallidum DNA yields from blood clots were only 1.0% at different centrifugal forces. The experiment with infected rabbit blood showed results similar to those mentioned above. In addition, sample processing time (within 48 h) and storage temperature (4 °C and 25 °C) did not affect T. pallidum DNA extraction efficiency. The T. pallidum DNA yield can be significantly improved by red blood cell lysis pretreatment and appropriate centrifugation. Furthermore, the T. pallidum DNA extraction yield is greater from whole blood or residual hematocytes from anti-coagulated blood than from plasma, serum or blood clots.

Molecular subtyping of Treponema pallidum and associated factors of serofast status in early syphilis patients: Identified novel genotype and cytokine marker

Serofast, a persistent nontreponemal serological response observed in early syphilis patients after conventional treatment, remains a concern of clinicians and syphilis patients. No consensus has been established, however, that defines an effective treatment strategy and clarifies the pathogenesis. In this study, 517 patients with early syphilis were enrolled and treated. Twelve months after treatment, 79.3% (410/517) of patients achieved serological cure, 20.1% (104/517) were serofast, and 0.6% (3/517) were serological failures. Multivariate analysis demonstrated that older age (>40 years) and lower baseline RPR titer (≤ 1:8) were associated with serofast status. We also identified 21 T. pallidum molecular subtypes among early syphilis patients and detected a new subtype, 14i/a. We found that the proportion of 14i/a type in serofast patients was significantly higher than that in patients with serological cure, predicting an increasing risk of serofast status. Levels of chemerin were higher in the serum of serofast cases than serological cure cases, potentially indicating a novel cytokine marker for serofast in early syphilis patients after therapy. We hope that these results contribute to improve guidelines for the management of syphilis patients who experience serofast.

Treponema pallidum ssp. pallidum identification by real-time PCR targetting the polA gene in paraffin-embedded samples positive by immunohistochemistry

Syphilis is a systemic and sexually transmitted infection caused by Treponema pallidum ssp. pallidum. This spirochete causes different clinical and subclinical stages depending on the duration of infection and immune status of the host. Several tests have been developed for diagnosis, and are classified into direct and indirect methods. The first one includes dark field microscopy, direct fluorescent antibody test in fluids or tissue, and molecular biology techniques. In the indirect method (serologic), the routine tests are used, and are divided in two categories: non-treponemal and treponemal ones. The objective of this work was to identify T. pallidum ssp. pallidum in paraffin-embedded skin biopsies positive by immunohistochemistry, using conventional polymerase chain reaction (PCR) and quantitative real time PCR (qPCR). We included a sample of 17 paraffin-embedded biopsies. DNA was extracted and processed by conventional PCR and real-time PCR with a TaqMan® probe to identify the polA gene. Using PCR, 11 tested positive (64.7%) and 6 (35.3%) were negative. With qPCR and TaqMan® probe, 100% of samples tested positive. The minimum number of spirochetes detected in each sample was 2. With this work, we can conclude that qPCR is a fast and very accurate method for diagnosis of syphilis in tissue specimens.

Serological Tests for Acquired Syphilis in Immuno-competent Patients

Serological tests represent a valuable tool for the diagnosis and monitoring the syphilis treatment. Non-treponemal antibodies are nonspecific to detect the infection, but antibody titers are used to monitor the effects of syphilis treatment. A definitive diagnosis of syphilis is made using treponemal tests, because they detect specific antibodies to the treponemal strains or treponemal fragments, which cause syphilis. These tests may remain reactive for years, sometimes for life, regardless of the therapy outcome. Even after successful treatment, approximately 85% of patients remain positive for treponemal antibodies for the rest of their lives. However, treponemal tests cannot differentiate past infections from a current infection. Therefore, we use a combination of specific and non-specific tests, the two most frequently used diagnostic algorithms. The traditional algorithm begins with a non-treponemal assay, and if it is positive, the treponemal test is done. A positive treponemal test indicates syphilis. The reverse serology algorithm detects early, primary, and treated syphilis that may be missed with traditional screening. However, non-treponemal test is necessary to detect patients with active syphilis.

A retrospective cross-sectional quantitative molecular approach in biological samples from patients with syphilis

Syphilis is the sexually transmitted disease caused by Treponema pallidum, a pathogen highly adapted to the human host. As a multistage disease, syphilis presents distinct clinical manifestations that pose different implications for diagnosis. Nevertheless, the inherent factors leading to diverse disease progressions are still unknown. We aimed to assess the association between treponemal loads and dissimilar disease outcomes, to better understand syphilis. We retrospectively analyzed 309 DNA samples distinct anatomic sites associated with particular syphilis manifestations. All samples had previously tested positive by a PCR-based diagnostic kit. An absolute quantitative real-time PCR procedure was used to precisely quantify the number of treponemal and human cells to determine T. pallidum loads in each sample. In general, lesion exudates presented the highest T. pallidum loads in contrast with blood-derived samples. Within the latter, a higher dispersion of T. pallidum quantities was observed for secondary syphilis. T. pallidum was detected in substantial amounts in 37 samples of seronegative individuals and in 13 cases considered as syphilis-treated. No association was found between treponemal loads and serological results or HIV status. This study suggests a scenario where syphilis may be characterized by: i) heterogeneous and high treponemal loads in primary syphilis, regardless of the anatomic site, reflecting dissimilar duration of chancres development and resolution; ii) high dispersion of bacterial concentrations in secondary syphilis, potentially suggesting replication capability of T. pallidum while in the bloodstream; and iii) bacterial evasiveness, either to the host immune system or antibiotic treatment, while remaining hidden in privileged niches. This work highlights the importance of using molecular approaches to study uncultivable human pathogens, such as T. pallidum, in the infection process.

Macrolide Resistance in the Syphilis Spirochete, Treponema pallidum ssp. pallidum: Can We Also Expect Macrolide-Resistant Yaws Strains?

Treponema pallidum ssp. pallidum (TPA) causes over 10 million new cases of syphilis worldwide whereas T. pallidum ssp. pertenue (TPE), the causative agent of yaws, affects about 2.5 million people. Although penicillin remains the drug of choice in the treatment of syphilis, in penicillin-allergic patients, macrolides have been used in this indication since the 1950s. Failures of macrolides in syphilis treatment have been well documented in the literature and since 2000, there has been a dramatic increase in a number of clinical samples with macrolide-resistant TPA. Scarce data regarding the genetics of macrolide-resistant mutations in TPA suggest that although macrolide-resistance mutations have emerged independently several times, the increase in the proportion of TPA strains resistant to macrolides is mainly due to the spread of resistant strains, especially in developed countries. The emergence of macrolide resistance in TPA appears to require a two-step process including either A2058G or A2059G mutation in one copy of the 23S rRNA gene and a subsequent gene conversion unification of both rRNA genes. Given the enormous genetic similarity that was recently revealed between TPA and TPE strains, there is a low but reasonable risk of emergence and spread of macrolide-resistant yaws strains following azithromycin treatment.

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

Treponema pallidum PCR (Tp-PCR) has been noted as a valid method for diagnosing syphilis. We compared Tp-PCR to a combination of darkfield microscopy (DFM), the reference method, and serologic testing in a cohort of 273 patients from France and Switzerland and found the diagnostic accuracy of Tp-PCR was higher than that for DFM.

Syphilis testing, typing, and treatment follow-up: a new era for an old disease

PURPOSE OF REVIEW

The past 15 years have seen a dramatic increase in syphilis diagnoses in several regions including China, North America, Western Europe and Australia. Worldwide, the disease remains prevalent, contributing to substantial adult morbidity and neonatal mortality. Testing and treatment strategies are largely informed by data from the early antibiotic era, but increasing use of molecular diagnostics and new screening strategies could improve the management of syphilis substantially.

RECENT FINDINGS

The review explores new testing strategies for syphilis, including the importance of screening test selection and advances in point-of-care diagnostics. It then examines molecular studies of Treponema pallidum, covering typing; macrolide resistance; association between genotype and phenotype and the use of PCR in testing and monitoring strategies.

SUMMARY

Clinicians should be aware of testing strategies employed by their laboratories to ensure optimal sensitivity and specificity. Locally available T. pallidum PCR assays may improve the diagnosis of early disease and inform antibiotic choice. Robust serologic follow-up is still required, but predictors of potential treatment failure, including PCR-measured bacterial load, have been identified. Re-treatment should be considered for patients in the serofast state. The publication of T. pallidum genomes would allow further and more detailed study of strains and disease pathogenesis.

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.

Current standards for diagnosis of syphilis: comparing the russian and foreign guidelines (part I)

Despite the abundance of existing laboratory methods the diagnosis of syphilis still faces many challenges. Though direct detection of T. pallidum plays an important role in early manifest forms of the disease, serological tests remain the mainstay of diagnosis. Traditional syphilis screening algorithm based on nontreponemal tests with subsequent confirmation using treponemal tests is a standard worldwide. Recently, the ability to automate the treponemal tests promotes the increasingly widespread implementation of reverse algorithm when these tests are used for syphilis screening. None of the current serological algorithms are able to reliably differentiate between active and previously treated syphilis, which causes uncertainty in the management of patients. There is no «gold standard» for the diagnosis of neurosyphilis, ocular, auricular and visceral syphilis. The interpretation of serological tests in children born to seropositive mothers is also complicated. Diagnosis of congenital syphilis in newborns and, consequently, the prescription of antibiotic therapy often depends on assessment of the adequacy of maternal treatment during pregnancy, which leads to subjective decisions. This article provides a comparative analysis of the «Federal guidelines for the management of patients with syphilis» and their foreign analogues, discusses significant peculiarities of these guidelines and reviews current concerns and controversies in syphilis diagnosis.

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.

[Clinical and paraclinical features of syphilitic uveitis]

INTRODUCTION

Syphilis, caused by Treponema pallidum agent, results in polymorphic and non-specific ocular manifestations. Early diagnosis and institution of individualized treatment play a large role in the prognosis. The increase in syphilis over the past several years requires the ophthalmologist to consider this diagnosis in the setting of any intraocular inflammatory involvement.

PURPOSE

To describe epidemiological, clinical and paraclinical features and natural history of syphilitic uveitis.

MATERIALS AND METHODS

Retrospective, descriptive and non-comparative study of a series of patients hospitalized between 2007 and 2013 in our department of ophthalmology for management of ocular inflammation associated with a positive syphilitic serology.

RESULTS

Thirteen patients of mean age 52.5 years ± 12.9 (33-82 years) were included. All were male and were followed for six months. Co-infection with human immunodeficiency virus (HIV) was present in four of them. Other risk factors discovered on history were unprotected sexual relations, multiple partners, homosexual relations, co-infection with another sexually transmitted disease (STD) or an occupational risk. Decreased visual acuity (VA) was present in all patients, with an average initial VA of 0.71 ± 0.81 LogMAR, i.e. 2/10. Involvement was bilateral in 38% (n=5) of cases. Papilledema was present in 10 patients. Seven patients exhibited vasculitis, 6 patients a necrotizing retinitis, 2 patients with placoid lesions, 7 patients with panuveitis and 2 patients with macular edema. We did not find any patients with isolated anterior uveitis. Three patients exhibited concomitant extraocular involvement with cutaneous palmoplantar lesions. Spectral domain optical coherence tomography (SD-OCT) found a fragmentation of the external limiting membrane and a disorganization of the ellipsoid line in two patients. Cerebrospinal fluid was studied for all patients. Eight of them exhibited lymphocytic meningitis, and we found the presence of anti-Treponema pallidum hemagglutination assay antibody (TPHA) in 9 patients and anti-veneral disease research laboratory antibody (VDRL) in 1 patient. Syphilis polymerase chain reaction (PCR) in the aqueous humor was positive in 50% (n=6) of studied cases and the PCR for Epstein Barr virus came back positive in four specimens out of eight. False positive reactions were observed for Lyme disease in eight patients. The four HIV-positive patients showed bilateral lesions more frequently, but less severe and with a favorable outcome. Antibiotic treatment with ceftriaxone (2 grams per day intramuscularly for 15 to 21 days) and local treatment (corticoids and mydriatics) in the case of inflammation of the anterior segment, allowed a regression of the inflammation in all of our patients as well as an improvement in VA (average final VA 0.09 ± 0.17 LogMAR, i.e. approximately 8/10). One Jarisch Herxheimer reaction occurred and was resolved with systemic corticosteroid therapy. A change in the retinal pigment epithelium was the main sequela in 44% of cases (n=8 eyes).

CONCLUSION

Every structure of the eye may be involved with syphilis; therefore, syphilis must be systematically sought during the etiologic assessment of ocular inflammation even in the absence of historical risk factors. HIV-positive patients must be handled in the same way as immunocompetent patients. Collaboration with the internist is essential for the diagnosis, monitoring, and staging, especially in search of neurosyphilis. The clinical course is favorable with early treatment.

Molecular typing of Treponema pallidum in the Czech Republic during 2011 to 2013: increased prevalence of identified genotypes and of isolates with macrolide resistance

From January 2011 to December 2013, a total of 262 samples, from 188 patients suspected of having syphilis were tested for the presence of treponemal DNA by PCR amplification of five chromosomal loci, including the polA (TP0105), tmpC (TP0319), TP0136, TP0548, and 23S rRNA genes. Altogether, 146 samples from 103 patients were PCR positive for treponemal DNA. A set of 81 samples from 62 PCR-positive patients were typeable, and among them, nine different genotypes were identified. Compared to a previous study in the Czech Republic during 2004 to 2010, the number of genotypes detected among syphilis patients in a particular year increased to six in both 2012 and 2013, although they were not the same six. The proportion of macrolide-resistant clinical isolates in this 3-year study was 66.7%.

Clinical prediction and diagnosis of neurosyphilis in HIV-infected patients with early Syphilis

The diagnosis of neurosyphilis (NS) is a challenge, especially in HIV-infected patients, and the criteria for deciding when to perform a lumbar puncture (LP) in HIV-infected patients with syphilis are controversial. We retrospectively reviewed demographic, clinical, and laboratory data from 122 cases of HIV-infected patients with documented early syphilis who underwent an LP to rule out NS, and we evaluated 3 laboratory-developed validated real-time PCR assays, the Treponema pallidum particle agglutination (TPPA) assay, the fluorescent treponemal antibody absorption (FTA-ABS) assay, and the line immunoassay INNO-LIA Syphilis, for the diagnosis of NS from cerebrospinal fluid (CSF) samples of these patients. NS was defined by a reactive CSF-VDRL test result and/or a CSF white blood cell (WBC) count of >20 cells/μl. Thirty of the 122 patients (24.6%) had early NS. Headache, visual symptoms, a CD4 cell count of <500 cells/μl, and viremia, as defined by an HIV-1 RNA count of ≥50 copies/ml, were associated with NS in multivariate analysis (P = <0.001 for each factor). Blood serum rapid plasma reagin (RPR) titers were not associated with early NS (P = 0.575). For the diagnosis of NS, the PCR, FTA-ABS, TPPA, and INNO-LIA assays had sensitivities of 58%, 100%, 68%, and 100%, specificities of 67%, 12%, 49%, and 13%, and negative predictive values of 85%, 100%, 84%, and 100%, respectively. Visual disturbances, headache, uncontrolled HIV-1 viremia, and a CD4 cell count of <500 cells/μl were predictors of NS in HIV-infected patients with early syphilis, while blood serum RPR titers were not; therefore, RPR titers should not be used as the sole criterion for deciding whether to perform an LP in early syphilis. When applied to CSF samples, the INNO-LIA Syphilis assay easily helped rule out NS.

Acute hypophysitis and hypopituitarism in early syphilitic meningitis in a HIV-infected patient: a case report

Background

Sexually transmitted diseases and most notably syphilis-infections are rising amongst men who have sex with men. In HIV-co-infected patients, an accelerated clinical course of syphilis neurological involvement is known.

Case presentation

A 46 year old HIV-positive male patient came in to our emergency department in the late evening with acute fever, rapidly progressive cephalgia and photophobia. Palmar skin efflorescence was evocative of an active syphilis infection. A reactive Treponema pallidum particle agglutination (TPPA) assay with positive Treponema pallidum-specific IgG/IgM immunofluorescence as well as a highly reactive Veneral diseases research laboratory (VDRL) test confirmed the diagnosis. Liquor pleocytosis, liquor protein elevation and a highly positive VDRL test in cerebrospinal fluid (CSF) were interpreted in context of the clinical symptoms as neurosyphilitic manifestations within an early syphilis infection (stage II). Cranial nuclear magnetic resonance scans of the sella turcica, which were performed due to low thyroidea stimulation hormone (TSH) and thyroxin levels, showed signs of hypophysitis such as pituitary gland enlargement and inhomogeneous contrast enhancement. Advanced endocrine laboratory testing revealed hypopituitarism. Fourteen days of intravenous ceftriaxone treatment and levothyroxine- and hydrocortisone-substitution led to complete disappearance of all clinical symptoms. Two months later, nuclear magnetic resonance scan showed normal pituitary size and that the syphilis serology had normalized.

Conclusion

We report to the best of our knowledge the first case of a HIV-positive patient with acute hypophysitis and hypopituarism due to early neurosyphilis infection. Ceftriaxone treatment and levothyroxine- and hydrocortisone-substitution led to the disappearance of all clinical symptoms. We strongly recommend to exclude syphilis infection in every clinical situation unclear in HIV-patients, especially when additional risk factors are known.

[A case of neurological syphilis mimicking Horton's disease and polymyalgia rheumatica]

BACKGROUND

Syphilis has been making a comeback over the last 10 years. Neurosyphilis can occur at any stage of the infection but is difficult to diagnose because of the existence of misleading forms, of which we describe an example below.

PATIENTS AND METHODS

A 56-year-old woman presented symptoms evoking polymyalgia rheumatica and giant-cell arteritis in a context of ibuprofen treatment for a few weeks. She also had myodesospsia, syphilids and syphilitic roseola, together with laboratory indicators of inflammation. A lumbar puncture revealed lymphocytic meningitis and a positive Treponema Pallidum Haemagglutination Assay (TPHA) for cerebrospinal fluid, thus confirming the diagnosis of neurosyphilis. Moreover, the ophthalmologic examination showed optic neuritis with papilla lesions of syphilitic origin. This was successfully treated with a 3-week course of penicillin G infusions.

CONCLUSION

Symptoms evocative of Horton's disease and polymyalgia rheumatica can reveal syphilis, a disease dubbed "the great simulator" on account of the variety of clinical forms it can take.

Comparison of CDC and sequence-based molecular typing of syphilis treponemes: tpr and arp loci are variable in multiple samples from the same patient

Background

Molecular typing of syphilis-causing strains provides important epidemiologic data. We tested whether identified molecular subtypes were identical in PCR-positive parallel samples taken from the same patient at a same time. We also tested whether subtype prevalence differs in skin and blood samples.

Results

Eighteen syphilis positive patients (showing both positive serology and PCR), with two PCR-typeable parallel samples taken at the same time, were tested with both CDC (Centers for Disease Control and Prevention) and sequence-based typing. Samples taken from 9 of 18 patients were completely typed for TP0136, TP0548, 23S rDNA, arp, and tpr loci. The CDC typing revealed 11 distinct genotypes while the sequence-based typing identified 6 genotypes. When results from molecular typing of TP0136, TP0548, and 23S rDNA were analyzed in samples taken from the same patient, no discrepancies in the identified genotypes were found; however, there were discrepancies in 11 of 18 patients (61.1%) samples relative to the arp and tpr loci. In addition to the above described typing, 127 PCR-positive swabs and whole blood samples were tested for individual genotype frequencies. The repetition number for the arp gene was lower in whole blood (WB) samples compared to swab samples. Similarly, the most common tpr RFLP type “d” was found to have lower occurrence rates in WB samples while type “e” had an increased occurrence in these samples.

Conclusions

Differences in the CDC subtypes identified in parallel samples indicated genetic instability of the arp and tpr loci and suggested limited applicability of the CDC typing system in epidemiological studies. Differences in treponemal genotypes detected in whole blood and swab samples suggested important differences between both compartments and/or differences in adherence of treponeme variants to human cells.