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Objectives: To investigate the efficacy of performing a pooling strategy of triple-anatomical site samples (pharyngeal, anorectal and urine samples) for simultaneous Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) nucleic acid amplification detection.Methods: A total of 117 specimen sets (pharyngeal, anorectal and urine) were collected from 98 men between 2014 and 2016. Double sampling of pharyngeal, anorectal and urine samples allowed for pooled and unpooled analyses using a multiplex Abbott Real Time CT/NG assay, together with confirmatory PCR testing in case of CT/NG positivity. Clinical and demographic data were analyzed.Results: The positivity rate for the triple-site pooled testing for CT and NG was 8.5% (10/117) and 6.8%, (8/117), respectively, compared to the single-site testing total positivity rate, which was 9.4% (11/117) and 4.3% (5/117) for CT and NG, respectively. Pooled analysis missed one CT-positive urine sample and one CT-positive anorectal sample could not be confirmed. In addition, less PCR inhibition was reported for the pooled sample (PS) testing and ERV-3 qPCR testing revealed ineffective sampling of self-collected anorectal swabs in two cases. No pharyngeal samples were positive for CT, nor were any urine samples positive for NG.Conclusion: This small study showed that PS testing is a possible testing strategy for screening high-risk men who have sex with men attending pre-exposure prophylaxis (PrEP) clinics. However, due to the low positivity rate of CT/NG in this study, larger evaluations are needed to confirm the effectiveness of CT/NG screening with multiple-site PS nucleic acid amplification test (NAAT) screening practices.

Aim: A diagnostic test that could detect Treponema pallidum antigens in urine would facilitate the prompt diagnosis of syphilis. Materials & methods: Urine from 54 individuals with various clinical stages of syphilis and 6 controls were pooled according to disease stage and interrogated with complementary mass spectrometry techniques to uncover potential syphilis biomarkers. Results & conclusion: In total, 26 unique peptides were uncovered corresponding to four unique T. pallidum proteins that have low genetic sequence similarity to other prokaryotes and human proteins. This is the first account of direct T. pallidum protein detection in human clinical samples using mass spectrometry. The implications of these findings for future diagnostic test development is discussed. Data are available via ProteomeXchange with identifier PXD009707.

There is a paucity of data on the immune reconstitution inflammatory syndrome (IRIS) in the Central African region. We followed ART-naive HIV-infected patients initiating antiretroviral therapy in an HIV clinic in Gabon, for 6 months. Among 101 patients, IRIS was diagnosed in five. All IRIS cases were mucocutaneous manifestations. There were no cases of tuberculosis (TB) IRIS, but active TB (n = 20) was associated with developing other forms of IRIS (p = 0.02). Six patients died. The incidence of IRIS is low in Gabon, with mild, mucocutaneous manifestations. Electronic supplementary material The online version of this article (doi:10.1007/s15010-017-1000-9) contains supplementary material, which is available to authorized users.

Background Current serology-based, treponemal-specific diagnostic tests detect antibodies reactive against T. pallidum molecules and cannot differentiate between past and current syphilis infections. Further, existing diagnostic tests for syphilis have non-optimal sensitivity and specificity and require expertise for test administration and interpretation. These limitations, combined with the rising number of syphilis infections, highlight the need for a reliable direct diagnostic assay to detect active syphilis. We sought to develop such an assay using immuno-mass spectrometry to detect T. pallidum proteins. Our results revealed that select T. pallidum proteins are glycosylated. Methods We developed antibodies directed against proteotypic, surrogate peptides from six prioritized T. pallidum biomarker proteins. These antibodies were tested using a technology called Stable Isotope Standards and Capture by Anti-Peptide Antibodies (SISCAPA), which involves antibody enrichment of the peptide surrogates coupled with their identification by mass spectrometry. The anti-peptide antibodies were tested by SISCAPA and in immunoblots to detect T. pallidum proteins in urine from patients with clinically confirmed active syphilis. Results Immunoblot analyses consistently identified T. pallidum proteins in urine samples from patients with syphilis. Initially, SISCAPA technology detected the surrogate peptides in only a fraction of the urine samples. However, deglycosylation of the proteins in the urine samples prior to SISCAPA analyses allowed successful identification of the T. pallidum biomarkers. Conclusion This is the first report of protein glycosylation during T. pallidum infection. The results show sample deglycosylation prior to SISCAPA analysis improves peptide detection and enables use of a SISCAPA-based direct diagnostic test for accurately detecting active syphilis. Further, the results suggest a potential mechanism of immune evasion used during infection, that of masking T. pallidum proteins from the immune system by the addition of glycosyl groups. These findings increase our understanding of T. pallidum infection and will assist with development of a non-invasive, sensitive and specific assay for syphilis. Disclosure No significant relationships.

In this study, we assessed if the superimposition of incident sexually transmitted infections (STIs) on HIV phylogenetic analyses could reveal possible sexual behaviour misclassifications in our HIV-infected population. HIV-1 sequences collected between 1997 and 2014 from 1169 individuals attending a HIV clinic in Antwerp, Belgium were analysed to infer a partial HIV transmission network. Individual demographic, clinical and laboratory data collected during routine HIV follow-up were used to compare clustered and non-clustered individuals using logistic regression analyses. In total, 438 (37.5%) individuals were identified in 136 clusters, including 76 transmission pairs and 60 clusters consisting of three or more individuals. Individuals in a cluster were more likely to have a history of syphilis, Chlamydia and/or gonorrhoea (P

Background HIV infection is accompanied by various systemic host responses, including activation of coagulation and the vascular endothelium. We sought to determine the impact of opportunistic coinfections in a central African setting. Methods This prospective study included 98 HIV-infected individuals in Gabon initiating combination antiretroviral therapy (cART) and followed them up for 6 months. Patients were stratified according to the presence of active tuberculosis (TB; n=19), mucocutaneous opportunistic infection ( n=9) or no opportunistic infection ( n=70). HIV-uninfected subjects were included as controls ( n=32). Plasma concentrations of 14 markers of coagulation, endothelial activation, extracellular matrix formation and tissue damage were measured with a multiplex assay at baseline and months 3 and 6 after cART initiation. Results HIV-infected patients showed elevated plasma levels of all biomarkers measured with exception of protein C, which was reduced. Concurrent TB was only associated with elevated concentrations of D-dimer, metal-lopeptidase inhibitor 1 and Tenascin-C. Mucocutaneous coinfection did not alter HIV-associated responses. Most markers measured declined but remained elevated despite response to cART. Conclusions HIV infection is associated with systemic pro-coagulant, vascular and damage responses. In an ambulatory setting, concurrent opportunistic infections have little if any influence on these responses and normalization is incomplete after response to cART. This suggests that these responses are mainly driven by HIV-associated immune activation and less so by opportunistic infections.

ObjectivesThe diagnosis of repeat syphilis and its follow-up remains challenging. We aimed to investigate if IgM testing may assist in the diagnosis of syphilis reinfection/relapse and its treatment follow-up.MethodsThis substudy was conducted in the context of a syphilis biomarker discovery study (ClinicalTrials.gov Nr: NCT02059525). Sera were collected from 120 individuals with a new diagnosis of syphilis (72 with repeat infections) and 30 syphilis negative controls during a cohort study investigating syphilis biomarkers conducted at a sexually transmitted infection/HIV clinic in Antwerp, Belgium. Syphilis was diagnosed based on a simultaneous positive treponemal and non-treponemal assay result and/or positive serum PCR targeting polA. Specimens collected at visit of diagnosis, and 3 and 6 months post-treatment were tested by two enzyme immunoassays (EIAs), recomWell (Mikrogen; MI) and Euroimmun (EU), to detect anti-treponemal IgM. Baseline specimens were also tested for anti-treponemal IgM using a line immunoassay (LIA) recomLine (MI). Quantitative kinetic decay curves were constructed from the longitudinal quantitative EIA results.ResultsAn overall sensitivity for the diagnosis of syphilis of 59.8% (95% CI: 50.3%–68.7%), 75.0% (95% CI: 66.1%–82.3%) and 63.3% (95% CI: 54.8%–72.6%) was obtained for the EU, MI EIAs and MI LIA, respectively. When only considering repeat syphilis, the diagnostic sensitivity decreased to 45.7% (95% CI: 33.9%–58.0%), 63.9% (95% CI: 51.7%–74.6%) and 47.2% (95% CI: 35.5%–59.3%), respectively. IgM seroreverted in most cases 6 months after treatment. Post-treatment IgM concentrations decreased almost 30% faster for initial syphilis compared with repeat infection. The IgM EIAs and IgM LIA agreed from fairly to moderately (Cohen’s kappa (κ): 0.36 (EU EIA); κ: 0.53 (MI EIA); κ: 0.40 (MI LIA)) with the diagnosis of syphilis.ConclusionsIgM detection was not a sensitive method to diagnose syphilis and was even poorer in the diagnosis of syphilis repeat infections.

Background Syphilis continues to be a major global health threat with 11 million new infections each year, and a global burden of 36 million cases. The causative agent of syphilis, Treponema pallidum subspecies pallidum, is a highly virulent bacterium, however the molecular mechanisms underlying T. pallidum pathogenesis remain to be definitively identified. This is due to the fact that T. pallidum is currently uncultivatable, inherently fragile and thus difficult to work with, and phylogenetically distinct with no conventional virulence factor homologs found in other pathogens. In fact, approximately 30% of its predicted protein-coding genes have no known orthologs or assigned functions. Here we employed a structural bioinformatics approach using Phyre2-based tertiary structure modeling to improve our understanding of T. pallidum protein function on a proteome-wide scale. Results Phyre2-based tertiary structure modeling generated high-confidence predictions for 80% of the T. pallidum proteome (780/978 predicted proteins). Tertiary structure modeling also inferred the same function as primary structure-based annotations from genome sequencing pipelines for 525/605 proteins (87%), which represents 54% (525/978) of all T. pallidum proteins. Of the 175 T. pallidum proteins modeled with high confidence that were not assigned functions in the previously annotated published proteome, 167 (95%) were able to be assigned predicted functions. Twenty-one of the 175 hypothetical proteins modeled with high confidence were also predicted to exhibit significant structural similarity with proteins experimentally confirmed to be required for virulence in other pathogens. Conclusions Phyre2-based structural modeling is a powerful bioinformatics tool that has provided insight into the potential structure and function of the majority of T. pallidum proteins and helped validate the primary structure-based annotation of more than 50% of all T. pallidum proteins with high confidence. This work represents the first T. pallidum proteome-wide structural modeling study and is one of few studies to apply this approach for the functional annotation of a whole proteome. Electronic supplementary material The online version of this article (10.1186/s12900-018-0086-3) contains supplementary material, which is available to authorized users.

There is conflicting evidence as to whether repeat syphilis is more likely to present asymptomatically than initial syphilis. If it is, then this would motivate more frequent and long-term syphilis screening in persons with a history of multiple episodes of syphilis. We conducted detailed folder reviews of all individuals with 4 or more diagnoses of syphilis between 2000 and 2017 at the Institute of Tropical Medicine, Antwerp, and assessed if there was a difference in the proportion presenting with symptomatic (primary and secondary) vs asymptomatic (latent) syphilis in initial vs repeat syphilis. Forty-five clients with 4 or more episodes of syphilis were included in the study. All were HIV-infected. Repeat episodes of syphilis were less likely to be symptomatic than initial episodes (35/160 [21.9%] vs 28/45 [62.2%]; P < .001). Frequent screening in those with HIV infection may be the only way to diagnose repeat episodes of syphilis. Care providers can use this information to motivate persons with multiple episodes of syphilis to be screened every 3 to 6 months.

Background: Ascertaining if the clinical and immunological response to repeat syphilis differs from that in initial syphilis may assist in designing optimal syphilis screening strategies and vaccine design. Methods: We prospectively recruited 120 patients with a new diagnosis of (baseline) syphilis. During a 24-month follow-up period, 11 of these patients had a further diagnosis of (repeat) syphilis. We conducted a paired comparison of their plasma cyto-chemokines at baseline and repeat syphilis. Results: Comparing to their baseline infection, paired analyses of the 11 individuals with repeat infections during follow-up revealed that these reinfections had lower concentrations of Interferon (IFN) a (0.8 [Interquartile range (IQR) 0.8-0.8 vs. 12.2 [IQR 1.6-24.2], P = 0.004) and Chemokine (C-C motif) ligand (CCL) 4 (0.9 [IQR 0.9-12.2 vs. 17.5 [IQR 4.9-32.8], P = 0.022]. Conclusion: In this small study of 11 individuals, repeat syphilis was found to present with an attenuated immune response. The relevance of these findings to the design of optimal syphilis screening programs is discussed.

Objective: The prevalence of syphilis differs considerably between different populations and indi-vidual level risk factors such as number of sex partners seem unable to completely explain these differences. The effect of network level factors, such as the prevalence of partner concurrency, on syphilis prevalence has not hitherto been investigated. Study design: Linear regression was per-formed to assess the relationship between the prevalence of male concurrency and prevalence of syphilis in each of 11 countries for which we could obtain comparable data. The data for concur-rency prevalence was taken from the WHO/Global Programme on AIDS (GPA) sexual behavioural surveys. Syphilis prevalence rates were obtained from antenatal syphilis serology surveys done in the same countries. In addition, we used linear regression to assess if there was a relationship between syphilis and concurrency prevalence of various racial and ethnic groups within the United States and South Africa. Results: In the international study, we found a strong relationship between the prevalence of male concurrency and syphilis prevalence (r = 0.79, P = 0.003). In the subnational studies, the relationship between concurrency and syphilis prevalence was positive in all cases but was only statistically significant so in the case of South Africa’s racial groups (r = 0.98, P = 0.01). Conclusions: The findings of an ecological-level association between syphilis and partner concurrency need to be replicated but suggest that efforts directed towards decreasing partner concurrency may reduce syphilis prevalence.

It is unclear whether higher rates of sexual partner concurrency in Black South Africans are due to socioeconomic or cultural factors. We used a nationally representative sample of 9,728 individuals aged 16 to 55 from a study conducted in 2009 to examine how the norms pertaining to concurrency and the practice of concurrency vary by race, class, and gender. The percentage of men reporting point concurrency was 14%, 6.5%, and 2.5% in Blacks, coloreds, and Whites, respectively (p0.001). These percentages increased to 45.7%, 24.7%, and 11.7%, respectively, for those reporting lifetime concurrency (p0.001). In all the racial groups, men exhibited more favorable attitudes toward concurrency than women did. For a range of indicators, White men and women had less favorable attitudes toward concurrency than Black men and women. These differences remained after controlling for a range of confounding variables. In the adjusted logistic regression model, reported concurrency in men was associated with a younger age, Black race, being in the lowest income tertile, not being in a stable relationship, and expressing various positive attitudes toward concurrency.

Background Repeat syphilis is playing an increasing role in syphilis transmission in several populations. The assessment of repeat syphilis and response to treatment depends on accurately measuring intraindividual changes in non-treponemal tests. For a 0- to 6-month delta rapid plasma reagin (RPR) to be determined by routine individual RPR testing, samples are tested 6 months apart with differences in reagent batches, environmental conditions, and observers all leading to measurement errors. We hypothesized that conducting paired RPR testing (simultaneous testing of acute and convalescent samples) would enable a more accurate determination of delta RPR compared with individual testing. Methods A total of 120 study participants with a new diagnosis of syphilis were followed up at 0, 3, 6, 9, 12, 18, and 24 months, with RPR testing performed via individual testing at each study visit and at any suspected repeat syphilis. Rapid plasma reagin paired testing was performed on samples from 0 and 6 months and at any suspected repeat syphilis. Results The quantitative agreement ±1 dilution among paired and individual testing was 97.2%. There was no difference in the proportion with serofast status at 6 months: 21 (19.4%) and 19 (17.6%) according to paired and individual testing, respectively (P = 0.726). There was no statistically significant difference between 0- and 6-month delta RPR as determined by paired and individual testing in predicting seroresponse at 12 months (86.1% and 91.6% agreement with 12-month serofast/nonserofast classification, respectively; P = 0.262). Conclusions In our setting, individual testing performed equally well compared with paired testing. Follow-up of syphilis will remain onerous for the patient and the health care provider until new tests that can more accurately assess the response to therapy and repeat syphilis/treatment failure are developed.

Purpose. We evaluated the Sekure rapid plasma reagin (RPR-S) (Sekisui Diagnostics) automated quantitative latex immunoturbidimetric assay performed on the SK500 clinical chemistry system for clinical appropriateness. Methodology. Syphilis-infected individuals and controls were recruited into a prospective cohort study conducted at a sexually transmitted infection clinic in Antwerp, Belgium. Sera collected at diagnosis (baseline) and at 3, 6, 9 and 12 months post-treatment were tested with RPR-S and Macro-Vue RPR card (RPR-C) (Becton Dickinson) assays; RPR-C was considered the reference test. IgG/IgM enzyme immunoassay and Treponema pallidum polA serum PCR results were consulted by discordancy at baseline. Categorical analyses were performed and correlations were assessed with (non)-linear regression. Post-treatment longitudinal serological evolution was evaluated. Results. A total of 463 samples from 120 new syphilis cases from a variety of clinical stages and 30 syphilis-negative controls were tested. Initially, there was a weak correlation between quantitative RPR-C/S (r=0.15). In 70 samples there was a strong suspicion of hook effect. Of these, 57/70 sera were retested with an extra dilution step, resulting in an average 12-fold increase in quantitative RPR-S results. After the extra dilution, the overall qualitative RPR-C/S agreement was 78.89 %, (kappa-coefficient: 0.484). Of the 92 discordant samples, 9 were from the baseline visit (RPR-C titre: 1-8), which could have led to possible missed diagnoses using the RPR-S. Conclusions. The sensitivity and accuracy of the RPR-S test requires improvement before it can be used to diagnose syphilis and evaluate treatment efficacy in clinical practice.

Introduction High rates of sexual partner concurrency have been shown to facilitate the spread of various sexually transmitted infections. Assessments of explicit attitudes to concurrency have however found little difference between populations. We developed a concurrency implicit associations test (C-IAT) to assess if implicit attitudes towards concurrency may vary between individuals and populations and what the correlates of these variations are. Methods We recruited 869 Belgian (mean age 22.9, SD 5.1) and 70 South African (mean age 22.1, SD 2.5) university students to complete the C-IAT together with a questionnaire concerning sexual behaviour and explicit attitudes to concurrency. Results The Belgian students C-IATs demonstrated a strong preference for monogamy (−0.78, SD=0.41), with 93.2% of participants having a pro-monogamy C-IAT. The South Africans’ C-IAT demonstrated little preference for concurrency or monogamy (−0.009, SD=0.43), with 34.7% having a pro-monogamy C-IAT (p Conclusion We found larger differences in implicit than explicit attitudes towards concurrency between populations. These findings need to be replicated in larger samples.

Introduction An automated and accurate laboratory assay would be of considerable utility to the diagnosis of syphilis and treatment follow-up. We compared the Sekure RPR (Rapid Plasma Reagin) test performed on the SK500 Clinical Chemistry System to RPR card test results. Methods Serum samples were collected in the context of a 2 year observational cohort study of syphilis infected patients and controls. Syphilis was diagnosed using non-treponemal and treponemal testing. Sera collected at the time of diagnosis (M0) and at 3, 6, 9 and 12 months post-treatment were tested by a Macro-Vue RPR card test (RPR-C) (Becton Dickinson) and a Sekure RPR test (RPR-S) (Sekisui Diagnostics). RPR-S results are expressed in RPR units (R.U.), whereby 1 R.U. equals a 1-fold change in RPR-C titre. The agreement, linearity and reportable ranges were determined using RPR-C results as the gold standard. Linear regression was used to assess correlations from before and after implementation of an extra dilution step for samples with a strong suspicion of prozone effect. Results In total, 451 samples from 150 participants were tested, including 120 new syphilis cases and 30 controls. All 30 controls tested negative. Initially there was a weak correlation between RPR-C and RPR-S values (r=0.15). Further analyses identified 72 RPR-S samples with a strong suspicion of prozone effect. We therefore included an extra dilution step (10x) and retested 60/72 samples; values within the expected range were obtained for 58 of them. After implementing the extra dilution step the correlation was moderate (r=0.61), increasing further to r=0.91 for samples with RPR-C titres≤128. Of the 92 samples that tested RPR-C positive and RPR-S negative, 8 were from M0 (RPR-C: 1–4), which would have led to missed diagnoses. Conclusion A reasonable correlation was found between the tested methods for mid-range RPR-C results (titre ≤128). However, prozone may occur in samples with high antibody concentrations. More investigation is required to elucidate the false negative RPR-S results.

Introduction We aimed to compare two commercial enzyme immunoassays (EIA) for the detection of IgG and IgM anti- Treponema pallidum (Tp) antibodies. Methods Serum samples were collected in the context of a larger study looking at diagnostic biomarkers for syphilis. Patients with syphilis diagnosed by a treponemal and a non-treponemal assay, were followed for up to two years after treatment. Specimens collected at visit of diagnosis (B), and after three (M3) and six months (M6) of treatment were tested by EIAs detecting anti-Tp IgG and IgM from the manufacturers Euroimmun (EU) and Mikrogen (MI). Results We tested 338 samples collected from 119 new syphilis cases (23 primary (P), 49 secondary (S), 31 early latent (EL), 16 late latent (LL)) and 30 uninfected controls. A total of 40 participants contributed to 1 sample, 29 to 2 samples and 80 to 3 samples. The controls contributed only to the samples collected at B. Overall 147, 86 and 105 samples were obtained at B, M3 and M6, respectively. The IgM assays were in agreement for 78,1% of samples; it varied according to the syphilis stage: P: 82,1%; S: 72,5%; EL: 80,8%; LL: 72,1% and decreased from B to M3: B: 84,4%; M3: 73,3%; M6: 73,3%. More samples tested positive with the MI (149) versus the EU (100) (p versus the MI (300) assay. EU reported all control samples IgG negative, MI detected 1 borderline sample. Conclusion A good but not perfect agreement was observed for the EIAs detecting IgM. The agreement was highest in primary syphilis and lowest in late latent cases, and decreased over time of treatment. The MI IgM assay reported significantly more positive samples. Overall, we found a good agreement for the EIAs detecting IgG. Albeit that it was somewhat lower for primary syphilis and at baseline.

Introdution There may be a difference in the immune and inflammatory response to repeat as compared to initial syphilis. Methods Prospective study: We prospectively recruited patients with a new diagnosis of syphilis, described their clinical and demographic characteristics and tested their plasma for IFNa, IFNg, IL-1b, IL-12p40, IL-12p70, IP-10, MCP-1, MIP-1a, MIP-1β, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-17A (Luminex multiplex assay (EMD Millipore) and their serum with a quantitative Rapid Plasma Reagin (RPR) test (Macrovue, Becton, Dickinson) at baseline pre-treatment and 6 months following therapy. The Mann-Whitney U-test was used to assess if cytokine levels and RPR titres differed between those with initial and repeat syphilis sampled at baseline and 6 month time points. Retrospective study: We compared RPR response kinetics between initial and repeat syphilis in persons attending our HIV/STI clinic. Results Prospective study: 91 individuals, 36 with initial- and 55 with repeat syphilis, were included in the study. At baseline visit those with initial syphilis were more likely to be symptomatic and had higher levels of IL-8, IL-10 and MIP-1β. By the 6 month visit IL-10 remained higher in those with initial syphilis. Median RPR titres were higher at baseline in the repeat compared to the initial infection groups in those with symptomatic (primary and/or secondary) syphilis (1/128 [IQR 1/64-1/256] vs. 1/64 [IQR 1/16-1/128], p=0.016) but not those with latent syphilis. Retrospective study: Syphilis was diagnosed in 1 027/12 520 individuals tested. Repeaters had higher RPR titres at diagnosis and a stepwise increase in RPR titre with number of previous syphilis episodes. They had a different RPR response kinetic: they were less likely to be serofast and less likely to serorevert than initial syphilis. Not one of those with 4 or more episodes of syphilis seroreverted. Conclusion Repeat syphilis has a different clinical presentation and immunological response than initial infection. We discuss the implications for clinicians and epidemiologists.

Introduction Syphilis reinfections are playing an increasing role in syphilis transmission in a number of populations. The assessment of reinfection and response to treatment depends on accurately measuring intraindividual changes in non-treponemal tests (delta-NTTs). In a 0 to 6 month delta-RPR determined by routine RPR testing (RT), samples would be tested 6 months apart with differences in reagent batches, environmental temperatures and observers all leading to measurement errors. We hypothesised that conducting paired RPR (PT) would enable a more accurate determination of delta-RPR than RT. Methods 120 patients with a new diagnosis of syphilis were followed up at 0,3,6,9,12,18 and 24 months with RPRs performed via RT at each study visit and at any suspected reinfection. RPR PT was performed at 0 and 6 months and at any suspected reinfection. Results The quantitative agreement +/-1 dilution among PT and RT was 97.4%. There was no difference in the proportion with an incomplete serological response at 6 months: 21 (19.4%) and 19 (17.6%) according to PT and RT, respectively (p=0.726). There was no statistically significant difference between 0 to 6 month delta-RPR as determined by PT and RT in predicting seroresponse at 12 months (86.1% and 91.6% agreement with 12 month classification, respectively, p=0.262. PT did not reduce the numbers of those classified with asymptomatic reinfections. Conclusion In our setting routine PT is unlikely to be worth the considerable effort and cost it entails. Further research is required to assess its utility in specific circumstances.

ObjectiveWe aimed to asses if there are differences in the clinical presentation and immune response of repeat as compared with initial syphilis.MethodsProspective study: we prospectively recruited all patients with a new diagnosis of syphilis and tested their plasma for a range of cytochemokines and rapid plasma reagin (RPR) at baseline pretreatment and 6 months following therapy. Retrospective study: we compared RPR assay response kinetics between initial and repeat syphilis in persons attending our HIV/STI clinic from 1993 to 2016.ResultsProspective study: a total of 91 individuals, 36 with initial syphilis and 55 with repeat syphilis, were included in the study. At baseline visit, those with initial syphilis were more likely to be symptomatic and have higher levels of interleukin-10 than repeaters. At baseline, median RPR titres were higher in the repeat than the initial infection groups. Repeaters were less likely than those with initial infections to serorevert to a negative RPR and be serofast (Retrospective study: syphilis was diagnosed in 1027/43 870 individuals tested. At diagnosis, repeaters had higher RPR titres and a stepwise increase in RPR titre with number of syphilis episodes. They had a different RPR test response kinetic: they were less likely to be serofast and to serorevert than initial syphilis at 6 and 12 months. No individuals with four or more previous episodes of syphilis seroreverted.ConclusionRepeat syphilis has a different clinical presentation and immunological response to initial infection.

Centers for Disease Control and Prevention and sequencing-based treponeme typing was used to analyze 72 blood samples, collected from human immunodeficiency virus and syphilis co-infected patients during 2014 to 2015 in Antwerp, Belgium. Twenty-nine (40.3%) isolates were polymerase chain reaction positive for Treponema pallidum, and all tested were macrolide-resistant. Four genotypes were identified by sequencing-based typing including two new genotypes, U4NR8 and SU9R8, whereas enhanced Centers for Disease Control and Prevention typing revealed 7 subtypes.

Prevalence estimates of various bacterial sexually transmitted infections in South Africa have declined considerably since the mid-1990s. Syphilis among pregnant women, for example, declined from 10.8% in 1998 to 2.8% in 2001. We used Pearson’s correlation coefficients to estimate the association between the prevalence of syphilis/male urethral discharge/male genital ulcers and the peak HIV prevalence at a district and provincial level in the early and late phases of the HIV epidemic in South Africa. Prevalence estimates of syphilis, male urethral discharge and male genital ulcers during the period preceding the peak HIV prevalence were all positively correlated with the peak HIV prevalence at a provincial level (Pearson’s correlation coefficient [ r] = 0.83, p = 0.006; r = 0.66, p = 0.052; r = 0.79, 0.011, respectively). These relationships all switched to a negative association later in the HIV epidemic at a provincial level ( r = −0.53, p = 0.14; r = −0.73, p = 0.130; r = −0.54, p = 0.027, respectively). AIDS mortality may have played an important role in the decline of bacterial sexually transmitted infections such as syphilis in this region. Consequently, the relatively recent scale-up of antiretroviral therapy may result in a resurgence of syphilis and other sexually transmitted infections as observed in high-income countries.

Background It is not known if there is a difference in the immune response to syphilis between HIV-infected and uninfected individuals. Methods We prospectively recruited all patients with a new diagnosis of syphilis and tested their plasma for IFNα, IFNγ, IL-1β, IL-12p40, IL-12p70, IP-10, MCP-1, MIP-1α, MIP-1β, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10 and IL-17A at baseline pre-treatment and 6 months following therapy. Results A total of 79 HIV-infected [44 primary/secondary syphilis (PSS) and 35 latent syphilis (LS)] and 12 HIV-uninfected (10 PSS and 2 LS) cases of syphilis and 30 HIV-infected controls were included in the study. At the baseline visit, compared to the control group, concentrations of IL-10 were significantly elevated in the HIV-infected and uninfected groups. The level of IL-10 was significantly higher in the HIV-infected compared to the HIV-uninfected PSS group (25.3 pg/mL (IQR, 4.56–41.76) vs 2.73 pg/mL (IQR, 1.55–9.02), P = 0.0192). In the HIV-infected PSS group (but not the HIV-infected LS or HIV-uninfected PSS groups) the IP-10, MIP-1b, IL-6 and IL-8 were raised compared to the controls. IL-10 levels decreased but did not return to control baseline values by 6 months in HIV infected PSS and LS and HIV uninfected PSS. Conclusion PSS and LS in HIV-infected individuals is characterized by an increase in inflammatory and anti-inflammatory cytokines such as IL-10. The increase of IL-10 is greater in HIV-infected than uninfected individuals. Further work is required to ascertain if this is part of an immunological profile that correlates with adverse outcomes such as serofast syphilis and neurosyphilis, in HIV-infected individuals. Electronic supplementary material The online version of this article (doi:10.1186/s12879-017-2201-7) contains supplementary material, which is available to authorized users.

Background The spirochete bacterium Treponema pallidum ssp. pallidum is the etiological agent of syphilis, a chronic multistage disease. Little is known about the global T. pallidum proteome, therefore mass spectrometry studies are needed to bring insights into pathogenicity and protein expression profiles during infection. Methodology/Principal Findings To better understand the T. pallidum proteome profile during infection, we studied T. pallidum ssp. pallidum DAL-1 strain bacteria isolated from rabbits using complementary mass spectrometry techniques, including multidimensional peptide separation and protein identification via matrix-assisted laser desorption ionization-time of flight (MALDI-TOF/TOF) and electrospray ionization (ESI-LTQ-Orbitrap) tandem mass spectrometry. A total of 6033 peptides were detected, corresponding to 557 unique T. pallidum proteins at a high level of confidence, representing 54% of the predicted proteome. A previous gel-based T. pallidum MS proteome study detected 58 of these proteins. One hundred fourteen of the detected proteins were previously annotated as hypothetical or uncharacterized proteins; this is the first account of 106 of these proteins at the protein level. Detected proteins were characterized according to their predicted biological function and localization; half were allocated into a wide range of functional categories. Proteins annotated as potential membrane proteins and proteins with unclear functional annotations were subjected to an additional bioinformatics pipeline analysis to facilitate further characterization. A total of 116 potential membrane proteins were identified, of which 16 have evidence supporting outer membrane localization. We found 8/12 proteins related to the paralogous tpr gene family: TprB, TprC/D, TprE, TprG, TprH, TprI and TprJ. Protein abundance was semi-quantified using label-free spectral counting methods. A low correlation (r = 0.26) was found between previous microarray signal data and protein abundance. Conclusions This is the most comprehensive description of the global T. pallidum proteome to date. These data provide valuable insights into in vivo T. pallidum protein expression, paving the way for improved understanding of the pathogenicity of this enigmatic organism., Author Summary Syphilis remains a major cause of morbidity and mortality worldwide. The bacterium causing syphilis, Treponema pallidum ssp. pallidum, has evolved into a highly distinctive organism that is only able survive (and be propagated) in mammals. In humans it can evade the immune system for decades with devastating consequences. Much remains to be learned about how it accomplishes this. Only a minority of its predicted proteins have been detected experimentally thus far. We aimed to more comprehensively characterize the proteins of this organism. Since it cannot be cultured in vitro, we cultured T. pallidum in rabbits and analyzed extracted proteins using different mass spectrometry methods, a manner of detecting proteins with high accuracy. In total, we detected more than half of the predicted number of proteins that could be expressed by this bacterium (N = 557). For approximately half of the proteins, we succeeded in characterizing their predicted cellular location using an array of bioinformatic tools and catalogued their function. This is the most comprehensive analysis of the T. pallidum proteome to date. This study lays the groundwork for other protein investigations of this unique organism.

Despite overall global progress in tuberculosis (TB) control, TB remains one of the deadliest communicable diseases. This study prospectively assessed TB epidemiology in Lambarene, Gabon, a Central African country ranking 10th in terms of TB incidence rate in the 2014 World Health Organization TB report. In Lambarene, between 2012 and 2014, 201 adult and pediatric TB patients were enrolled and followed up; 66% had bacteriologically confirmed TB and 95% had pulmonary TB. The human immunodeficiency virus (HIV) coinfection rate was 42% in adults and 16% in children. Mycobacterium tuberculosis and Mycobacterium africanum were identified in 82% and 16% of 108 culture-confirmed TB cases, respectively. Isoniazid (INH) and streptomycin yielded the highest resistance rates (13% and 12%, respectively). The multidrug resistant TB (MDR-TB) rate was 4/91 (4%) and 4/13 (31%) in new and retreatment TB cases, respectively. Treatment success was achieved in 53% of patients. In TB/HIV coinfected patients, mortality rate was 25%. In this setting, TB epidemiology is characterized by a high rate of TB/HIV coinfection and low treatment success rates. MDR-TB is a major public health concern; the need to step-up in-country diagnostic capacity for culture and drug susceptibility testing as well as access to second-line TB drugs urgently requires action.

Background: Could we have predicted national peak HIV based on syphilis prevalence in the 1990s? Earlier studies have shown positive correlations between various sexually transmitted infections at different population levels. In this article we test the hypothesis that there was a residual variation in the national prevalence rates of syphilis and that these rates could predict subsequent peak HIV prevalence rates. Methods: This analysis uses linear regression to evaluate the country-level relationship between antenatal syphilis prevalence (1990-1999) and peak HIV prevalence. Antenatal syphilis data were taken from an Institute for Health Metrics and Evaluation database on the prevalence of syphilis in low-risk populations. Peak HIV prevalence was calculated based on data taken from the Global Health Observatory Data Repository of the World Health Organization. Results: A moderately strong association is found for the 76 countries with data available (R² = 0.53 P < 0.001). The association was weakened but remained significantly positive when we adjusted for the type of syphilis testing used. Conclusions: Syphilis prevalence in the 1990s predicted approximately 53% of the variation in peak HIV prevalence. Populations with generalized HIV epidemics had a higher prevalence of syphilis in the pre-HIV period. This finding provides additional rationale to carefully monitor sexual behavior sexual networks and sexually transmitted infection incidence in these populations.

Background:Current syphilis diagnostic strategies are lacking a sensitive manner of directly detectingTreponema pallidumantigens. A diagnostic test that could directly detectT. pallidumantigens in individuals with syphilis would be of considerable clinical utility, especially for the diagnosis of reinfections and for post-treatment serological follow-up.Methods:In this study, 11 candidateT. pallidumbiomarker proteins were chosen according to their physiochemical characteristics,T. pallidumspecificity and predicted abundance. Thirty isotopically labelled proteotypic surrogate peptides (hPTPs) were synthesized and incorporated into a scheduled multiple reaction monitoring assay. Protein extracts from undepleted/unenriched plasma (N = 18) and urine (N = 4) samples from 18 individuals with syphilis in various clinical stages were tryptically digested, spiked with the hPTP mixture and analysed with a triple quadruple mass spectrometer.Results:No endogenous PTPs corresponding to the eleven candidate biomarkers were detected in any samples analysed. To estimate the Limit of Detection (LOD) of a comparably sensitive mass spectrometer (LTQ-Orbitrap), two dilution series of rabbit cultured purifiedT. pallidumwere prepared in PBS. Polyclonal anti-T. pallidumantibodies coupled to magnetic Dynabeads were used to enrich one sample series; no LOD improvement was found compared to the unenriched series. The estimated LOD of MS instruments is 300T. pallidum/ml in PBS.Conclusions:Biomarker protein detection likely failed due to the low (femtomoles/liter) predicted concentration ofT. pallidumproteins. Alternative sample preparation strategies may improve the detectability ofT. pallidumproteins in biofluids.

Background. Syphilis is curable but Herpes Simplex Virus-2 (HSV-2) is not. As a result, the prevalence of syphilis but not HSV-2 may be influenced by the efficacy of national STI screening and treatment capacity. If the prevalence of syphilis and HSV-2 is found to be correlated, then this makes it more likely that something other than differential STI treatment is responsible for variations in the prevalence of both HSV-2 and syphilis. Methods. Simple linear regression was used to evaluate the relationship between national antenatal syphilis prevalence and HSV-2 prevalence in women in two time periods: 1990–1999 and 2008. Adjustments were performed for the laboratory syphilis testing algorithm used and the prevalence of circumcision. Results. The prevalence of syphilis was positively correlated with that of HSV-2 for both time periods (adjusted correlations, 20–24-year-olds: 1990–99: R2=0.54, P<0.001; 2008: R2=0.41, P<0.001 and 40–44-year-olds: 1990–99: R2=0.42, P<0.001; 2008: R2=0.49, P<0.001). Conclusion. The prevalence of syphilis and HSV-2 is positively correlated. This could be due to a common set of risk factors underpinning both STIs.

OBJECTIVE To demonstrate the importance of using a combined genetic and functional approach to correctly interpret a genetic test for monogenic diabetes. RESEARCH DESIGN AND METHODS We identified three probands with a phenotype consistent with maturity-onset diabetes of the young (MODY) subtype GCK-MODY, in whom two potential pathogenic mutations were identified: [R43H/G68D], [E248 K/I225M], or [G261R/D217N]. Allele-specific PCR and cosegregation were used to determine phase. Single and double mutations were kinetically characterized. RESULTS The mutations occurred in cis (double mutants) in two probands and in trans in one proband. Functional studies of all double mutants revealed inactivating kinetics. The previously reported GCK-MODY mutations R43H and G68D were inherited from an affected father and unaffected mother, respectively. Both our functional and genetic studies support R43H as the cause of GCK-MODY and G68D as a neutral rare variant. CONCLUSIONS These data highlight the need for family/functional studies, even for previously reported pathogenic mutations.

Purpose of review Bacterial vaginosis epidemiology has been transformed by new theoretical insights and methodologies, such as molecular sequencing. We summarize the progress made in these domains. Recent findings The vaginal microbiome can be classified in five to eight clusters. Bacterial vaginosis-type clusters typically constitute one of these clusters, but in higher risk women, it can constitute up to three clusters. The vaginal microbiomes may be fairly stable or be subject to rapid changes in their constitutive makeup. Bacterial vaginosis does not appear to be a single entity. Certain bacterial communities are associated with particular symptoms of bacterial vaginosis that are paired with unique adverse outcomes. Biofilm-producing Gardnerella vaginalis are likely to play an important role in initiating the structured polymicrobial biofilm that is a hallmark of bacterial vaginosis. Summary Longitudinal studies currently underway should help elucidate how to best define bacterial vaginosis and its subtypes. Risk factors and outcomes associated with particular bacterial vaginosis subtypes should also be further clarified through these studies.

Glucokinase is a key regulatory enzyme in the pancreatic beta-cell. It plays a crucial role in the regulation of insulin secretion and has been termed the glucose sensor in pancreatic beta-cells. Given its central role in the regulation of insulin release it is understandable that mutations in the gene encoding glucokinase (GCK) can cause both hyper- and hypoglycemia. Heterozygous inactivating mutations in GCK cause maturity-onset diabetes of the young (MODY) subtype glucokinase (GCK), characterized by mild fasting hyperglycemia, which is present at birth but often only detected later in life during screening for other purposes. Homozygous inactivating GCK mutations result in a more severe phenotype presenting at birth as permanent neonatal diabetes mellitus (PNDM). A growing number of heterozygous activating GCK mutations that cause hypoglycemia have also been reported. A total of 620 mutations in the GCK gene have been described in a total of 1,441 families. There are no common mutations, and the mutations are distributed throughout the gene. The majority of activating mutations cluster in a discrete region of the protein termed the allosteric activator site. The identification of a GCK mutation in patients with both hyper- and hypoglycemia has implications for the clinical course and clinical management of their disorder.

Although the rate of new tuberculosis (TB) cases has been falling worldwide, progress toward the targets for diagnosis and treatment of drug-resistant TB is far off-track. In countries with no reliable TB surveillance system, setbacks and progression of TB control is barely reflected and little is known on the situation in the field. Interviews with health professionals in Gabon revealed limited access to first- and second-line TB drugs and important deficiencies in basic TB control. National and international action needs to be taken to meet the global TB control targets.