Browsing by Subject "Syphilis"

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    Open Access
    A cross sectional analysis of Gonococcal and Chlamydial infections among men-who-have-sex-with-men in Cape Town, South Africa
    (Public Library of Science, 2015) Rebe, Kevin; Lewis, David; Myer, Landon; de Swardt, Glenn; Struthers, Helen; Kamkuemah, Monika; McIntyre, James
    BACKGROUND: Men-who-have-sex-with-men (MSM) are at high risk of HIV and sexually transmitted infection (STI) transmission. Asymptomatic STIs are common in MSM and remain undiagnosed and untreated where syndromic management is advocated. Untreated STIs could be contributing to high HIV rates. This study investigated symptomatic (SSTI) and asymptomatic STIs (ASTIs) in MSM in Cape Town. METHODS: MSM, 18 years and above, were enrolled into this study. Participants underwent clinical and microbiological screening for STIs. Urine, oro-pharyngeal and anal swab specimens were collected for STI analysis, and blood for HIV and syphilis screening. A psychosocial and sexual questionnaire was completed. STI specimens were analysed for Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) infection. RESULTS: 200 MSM were recruited with a median age of 32 years (IQR 26-39.5). Their median number of sex partners within the last year was 5 (IQR 2-20). 155/200 (78%) reported only male sex partners while 45/200 (23%) reported sex with men and women. 77/200 (39%) reported transactional sex. At enrolment, 88/200 (44%) were HIV positive and 8/112 (7%) initially HIV-negative participants seroconverted during the study. Overall, 47/200 (24%) screened positive for either NG or CT. There were 32 MSM (16%) infected with NG and 7 (3.5%) of these men had NG infections at two anatomical sites (39 NG positive results in total). Likewise, there were 23 MSM (12%) infected with CT and all these men had infections at only one site. Eight of the 47 men (17%) were infected with both NG and CT. ASTI was more common than SSTI irrespective of anatomical site, 38 /200 (19%) versus 9/200 (5%) respectively (p<0.001). The anus was most commonly affected, followed by the oro-pharynx and then urethra. Asymptomatic infection was associated with transgender identity (OR 4.09 CI 1.60-5.62), ≥5 male sex partners in the last year (OR 2.50 CI 1.16-5.62) and transactional sex (OR 2.33 CI 1.13-4.79) but not with HIV infection. CONCLUSIONS: Asymptomatic STI was common and would not have been detected using a syndromic management approach. Although molecular screening for NG/CT is costly, in our study only four MSM needed to be screened to detect one case. This supports dual NG/CT molecular screening for MSM, which, in the case of confirmed NG infections, may trigger further culture-based investigations to determine gonococcal antimicrobial susceptibility in the current era of multi-drug resistant gonorrhoea.
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    Open Access
    Functional insights from proteome-wide structural modeling of Treponema pallidum subspecies pallidum, the causative agent of syphilis
    (BioMed Central, 2018-05-16) Houston, Simon; Lithgow, Karen V; Osbak, Kara K; Kenyon, Chris R; Cameron, Caroline E
    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.
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    Open Access
    The global epidemiology of syphilis in the past century - a systematic review based on antenatal syphilis prevalence
    (Public Library of Science, 2016) Kenyon, Chris Richard; Osbak, Kara; Tsoumanis, Achilleas
    Author Summary: Syphilis rates have varied tremendously between different populations around the world. We conducted a systematic review of syphilis prevalence in pregnant women in 13 populations with available data for the last 100 years. Our findings were that in most populations syphilis prevalence dropped to under 1% before 1960. In the 2 populations from sub Saharan Africa, the syphilis prevalence remained around 6% until 50 years after the introduction of penicillin. Other systematic reviews were utilized to provide syphilis prevalence estimates for all countries with available data for the periods 1990-1999 and 2008. We assessed if there was a correlation between national syphilis prevalence in these periods and five explanatory factors. Only residence in sub-Saharan Africa was associated with syphilis prevalence in both time periods. These findings, considered in conjunction with other types of evidence we review, such as the strong correlations at population level between syphilis prevalence and those of Herpes Simplex Virus-2 prevalence and HIV prevalence, suggest that common risk factors may underpin the spread of all three of these sexually transmitted diseases. Establishing what these factors are is of great importance to improve the health of highly affected populations such as those in sub-Saharan Africa.
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    Open Access
    Increases in condomless chemsex associated with HIV acquisition in MSM but not heterosexuals attending a HIV testing center in Antwerp, Belgium
    (BioMed Central, 2018-10-19) Kenyon, Chris; Wouters, Kristien; Platteau, Tom; Buyze, Jozefien; Florence, Eric
    Background It has been speculated that the prevalence of chemsex is increasing in men who have sex with men and that this may be playing a role in the spread of HIV. Methods We assessed if the prevalence of reported chemsex was increasing and if chemsex was associated with HIV infection in clients attending the ‘Helpcenter’, Antwerp, between 2011 and 2017. This is a HIV/STI testing center that offers HIV/STI testing to HIV-uninfected individuals from key populations including MSM. Results We found an increase in the reporting of condomless sex associated with the use of a number of drugs, including ecstasy, amphetamines, GHB and cocaine in MSM (from 8 to 17%) but not in heterosexuals. Reporting condomless chemsex was associated with HIV infection (adjusted odds ratio 5.7 [95% confidence interval 3.2–10.4]). Conclusions Our findings provide further evidence of the importance of asking MSM clients about the use of psychoactive substances during consultations and tailoring interventions such as pre exposure prophylaxis, more frequent STI screening and substance abuse counseling accordingly.
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    Open Access
    Single-dose benzathine penicillin in infants at risk of congenital syphilis : results of a randomised study
    (1997) Radcliffe, M; Meÿer, M; Roditi, D; Malan, A
    OBJECTIVE: To determine the efficacy of single-dose benzathine penicillin G in infants at high risk of congenital syphilis. DESIGN: Randomised study comparing benzathine penicillin with no therapy. SETTING: Peninsula Maternal and Neonatal Service, Cape Town. SUBJECTS: Asymptomatic infants born to mothers with untreated syphilis whose VDRL titre was 32 or more. OUTCOME MEASURES: The number of cases of congenital syphilis was determined by results of IgM Western blots and follow-up VDRL titres. RESULTS AND CONCLUSIONS: Of 8 patients followed up in the non-treatment group, 4 had congenital syphilis while 0/11 had the disease (P = 0.035) in the group receiving benzathine penicillin. Although the exact failure rate is unknown, benzathine penicillin is effective in preventing symptomatic congenital syphilis when administered to high-risk newborns.
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    The immunological response to syphilis differs by HIV status; a prospective observational cohort study
    (2017) Kenyon, Chris; Osbak, Kara Krista; Crucitti, Tania; Kestens, Luc
    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.