Sensitivity and specificity of a syphilis rapid diagnostic test in blood donors' samples

Rapid Diagnostic Tests (RDT) are useful to identify syphilis cases, particularly for hard-to-reach populations and if laboratory services are scarce. However, RDT performance may be suboptimal. We aimed to assess the sensitivity and specificity of a syphilis RDT using well-characterized blood donors' samples. We categorized samples from 811 blood donors into five groups: 1 - Samples with reactive Chemiluminescence (QML), FTA-Abs, and VDRL; 2 - Samples with reactive QML and FTA-Abs, and nonreactive VDRL; 3 - Samples with reactive QML, and nonreactive for other markers (false-positives); 4 - Controls with nonreactive QML; and 5 - Samples reactive for HIV, with nonreactive QML. Sensitivity was tested in groups 1 (overall and according to VDRL titers) and 2; specificity was tested in groups 3‒5. The RDT had high specificity, even in samples reactive for HIV. The sensitivity was high (91.9%) in samples with reactive VDRL but varied between 75.0%‒100% according to VDRL titers. The overall sensitivity was lower (81.3%) in samples with reactive FTA-Abs and nonreactive VDRL. The RDT is a useful tool to detect active syphilis but may be more limited for cases with very early or remote infection, or those with prior treatment. When higher sensitivity is needed, additional strategies including recurrent testing or laboratory-based tests may be required.

High Incidence, Reinfections, and Active Syphilis in Populations Attending a Specialized HIV Clinic in Mexico, a Dynamic Cohort Study

Syphilis, a sexually transmitted infection, has reemerged in many vulnerable groups around the world. The objective of the current study was to determine the prevalence and incidence of syphilis among people who attended a specialized HIV clinic in Mexico from 2011 to 2015. Databases from the laboratory were analyzed, and the following four groups were formed: people seeking HIV-1 voluntary counseling and testing (VCT), people in prison (PPr), people living with HIV (PLWH), and patients from primary care clinics (others). The diagnosis of syphilis was made using the reverse algorithm; antibody titers were examined to determine the stage of infection. Baseline data were analyzed and, with follow-up information, a retrospective dynamic cohort was formed. Factors associated with the seroprevalence of syphilis and active syphilis were evaluated by the chi-square test. Moreover, risk factors for the incidence of syphilis were described. A total of 81,863 baseline individuals were analyzed. The seroprevalence of syphilis was 9.9% in the VCT group, 8.2% in the PPr group, 37.0% in the PLWH group, and 8.7% in the others group; the prevalence of active syphilis was 1.7-13.1%. A total of 11,124 people were followed up. The incidence (cases per 100 person-years) was 3.5 among the VCT group, 16.0 among the PLWH group, and < 0.1 among both the PPr and others groups, respectively; moreover, the frequency of reinfections was 11.1-24.4%. The high prevalence and incidence of syphilis, active syphilis, and reinfections among men, transgender people, individuals aged 20-39 years, and people with a history of HIV or hepatitis B suggest that it is critical to improve prevention, diagnosis, and treatment measures to stop the reemergence of syphilis. There are also new factors such as methamphetamine use, group sex, or contacting partners over the internet that are associated with syphilis. In addition, HIV preexposure prophylaxis could contribute to the increased incidence of syphilis by providing false security in the prevention of STIs, thereby increasing risky sexual behaviors.

Syphilitic aortitis: about a case in South Colombia

The case of a 73-year-old female patient obtained and resident of Florencia, Caquetá (Colombia), with a history of hypertension who is admitted to a highly complex hospital due to a 3-month clinical picture of constant evolution in pain is presented. Thoracic oppressive type in the anterior region of the left thorax, non-irradiated, of intensity 8/10. The echocardiogram shows calcified aortic valve disease with severe aortic stenosis, aortic regurgitation, left ventricular hypertrophy, and mild grade mitral regurgitation. Within the pre-surgical studies, she presented VDRL with 1:4 dilutions and the diagnosis was confirmed with the result of the treponemal test and other infectious diseases were ruled out. Valvular replacement was performed with a bioprosthesis plus a supra-coronary valvular tube. In the biopsy, chronic scar valvulitis with extensive calcifications was confirmed. After the surgical intervention, discharge was performed due to adequate clinical evolution.

[Serologic surveillance indicators analysis among syphilis-infected pregnant women in East China]

Objective: To analyze serologic surveillance indicators during pregnancy among syphilis-infected women who delivered in 2013 in East China. Methods: Data were from national 'Information System of Prevention of Mother-to-child Transmission of HIV, syphilis and HBV Management' and in total 5 206 syphilis-infected pregnant women who delivered in 2013 and in East China were involved in the analysis. Information on demographic characters, laboratory tests, and treatment regimens were collected. The maternal non-treponemal testing surveillance and titer distribution were described and compare the proportions between pregnant women receiving standard testing and non-standard testing, taking baseline testing and testing before delivery or at the third trimester. Multivariate logistic regression model was analyzed using maternal titer control as dependent variable, using prior history of syphilis infection, syphilis stages, titer, gestational weeks of treatment initiation and treatment regimens as independent variables in 3 940 pregnant women with both baseline testing results and testing results before delivery or at the third trimester. Results: The ages of the 5 206 syphilis infected pregnant women were (28.1±5.8) years old. The numbers of women received penicillin treatment, other treatment regimens and no treatment were 2 967 (57.0%), 281 (5.4%), and 1 958 (37.6%), respectively. The number of women with maternal seroconversion, 4-fold or greater titer decline, or titer increase were 349 (6.7%), 251 (4.8%) and 28 (0.5%). Multivariate analysis results showed that compared with pregnant women with prior history of syphilis, the OR(95%CI) for maternal titer control was 1.49 (1.18-1.88) among those with syphilis-infection history. Compared with pregnant women initiated treatment at 28 gestational weeks or before, the OR (95%CI) for maternal titer control was 4.09 (3.19-5.24) among those who initiated treatment after 28 gestational weeks. Compared with pregnant women initiated treatment at 28 gestational weeks or before, the OR (95%CI) for maternal titer control was 4.09 (3.19-5.24) among those who initiated treatment after 28 gestational weeks or received no treatment. Compared with pregnant women received penicillin treatment, the OR (95%CI) for maternal titer control among those received non-penicillin treatment and those received no treatment were 2.35 (1.46-3.76) and 1.55 (1.13-2.12), respectively. Conclusion: In East China, the proportion of women achieved seroconversion or 4-fold or greater titer decline during pregnancy was very low. Pregnant women with no prior history of syphilis infection, early maternal initiation of treatment, and penicillin treatment were more likely to reach maternal titer control.

Serologic Response to Treatment in Human Immunodeficiency Virus-Negative Syphilis Patients Using Automated Serological Tests: Proposals for New Guidelines

Background

Automated analyzer-based nontreponemal serological tests for syphilis (STS) have been used for several decades.

Objective

In this study, we evaluated serological responses to treatment and proposed clinical guidelines for automated STS.

Methods

This retrospective cohort study analyzed human immunodeficiency virus-negative syphilis patients who were diagnosed with automated rapid plasma reagin (auto RPR) tests as a nontreponemal STS, and who also received the fluorescent treponemal antibody-absorption test as a confirmatory test. The ratio of auto RPR values after treatment against those at baseline was defined as the auto RPR ratio for the analysis of the serological response to treatment. The cutoff value for reliable seroreversion prediction was assessed with receiver-operating-characteristic curves.

Results

Overall, 89.7% of participants (78/87) seroreverted and 10.3% of participants (9/87) remained serofast during the two-year follow-up period. We were unable to describe trends in the changes among auto RPR values within six months after treatment because of high variation. All of the patients who had an auto RPR ratio ≥1.0 after six months continuously had positive serologic results during their 24-month follow-up and were classified as a serofast group. The receiver-operating-characteristic curves revealed a 25% reduction in auto RPR values nine months after treatment and predicted seroreversion with a sensitivity of 96.2% and a specificity of 100%.

Conclusion

The most important primary checkpoint for syphilis treatment response is an increase in automated nontreponemal STS six months after treatment. Thus, we recommend monitoring the treatment response with an auto RPR.

[Reached multifocal secondary syphilis: A case presentation]

INTRODUCTION

Syphilis is a sexually transmitted infection (STI) related to Treponema pallidum. Secondary syphilis is the blood-borne systemic spread of Treponema.

OBSERVATION

We report the case of secondary syphilis in a patient without risk of STIs factor. The clinical picture began with a genital affection followed by oral erosions and ulcers and an anterior and then posterior uveitis. Serology established the diagnosis and intravenous penicillin G treatment allowed for healing.

DISCUSSION

Called the "great pretender" because of its clinical polymorphism, secondary syphilis can lead to formidable neurological and ophthalmological complications. Serological diagnosis is based on the use of treponemal and a nontreponemal tests. Penicillin G remains the treatment of choice and must be adapted according to the clinical damage.

Factors associated with failure of clinical screening among blood donors who have altered serological results in the Centro Regional de Hemoterapia de Ribeirão Preto

OBJECTIVE

This study aimed to investigate the frequency of positive results for hepatitis B and C, HIV and syphilis in blood donations at the Centro Regional de Hemoterapia de Ribeirão Preto, to describe donors with positive results according to some demographic and socioeconomic variables, to identify risk factors associated to these donors and the reasons that they were not detected during clinical screening.

METHODS

A descriptive study was performed between July 1(st) 2005 and July 31(st) 2006 by interviewing 106 donorsafter medical consultations where they were informed of positive results for hepatitis B, hepatitis C, HIV or syphilis.

RESULTS

There was a predominance of first-time donors, males, under 50-year olds, married individuals, from Ribeirão Preto, with elementary education, low economic status and of people who donated at the request of friends or relatives. Hepatitis C was the most frequently detected infection (56.6%), followed by hepatitis B (20.7%), HIV (12.3%) and syphilis(10.4%). About 40% of donors had omitted risk factors for different reasons: because they trusted the results of serological tests, did not feel comfortable about talking of risk factors or did not consider them relevant. Other justifications were the duration of the interview, the interviewer was unskilled, embarrassment and doubts about confidentiality.

CONCLUSION

The results indicate the need for changes in the approach to clinical screening and a review of methods to attract and guide potential donors.