Silver K. Vargas

Laboratory Evaluation of a Dual Rapid Immunodiagnostic Test for HIV and Syphilis Infection

ABSTRACT New dual tests for HIV and syphilis have been developed. Our study aimed to evaluate the laboratory performance of a dual rapid immunodiagnostic test for HIV and syphilis. Our evaluation showed high performance of this dual rapid test, which should be considered for implementation to increase screening coverage and efficiency.

Field evaluation of a dual rapid diagnostic test for HIV infection and syphilis in Lima, Peru

Objectives Screening for HIV and syphilis in key populations is recommended by the WHO to reduce the morbidity, mortality and transmission associated with undiagnosed and untreated infections. Rapid point-of-care tests that can detect multiple infections with a single fingerprick whole blood specimen using a single device are gaining popularity. We evaluated the field performance of a rapid dual HIV and syphilis test in people at high risk of HIV and syphilis infections. Methods Participants included men who have sex with men and transgender women recruited in Lima, Peru. Reference standard testing for detection of HIV and syphilis infections, conducted using blood samples from venipuncture, included Treponema pallidum particle agglutination and fourth-generation HIV enzyme immunoassay for which positive results had a confirmation HIV Western blot test. For the evaluation test, SD BIOLINE HIV/Syphilis Duo test (Standard Diagnostics, Korea), a fingerprick blood specimen was used. Sensitivity and specificity were calculated and the exact binomial method was used to determine 95% CIs. Results A total of 415 participants were recruited for the study. The dual test sensitivity for detection of T. pallidum infection was 89.2% (95% CI 83.5% to 93.5%) and specificity 98.8% (95% CI 96.5% to 99.8%). For detection of HIV infection, the sensitivity of the dual test was 99.1% (95% CI 94.8% to 100%) and specificity 99.4% (95% CI 97.7% to 99.9%). Conclusions This high performing dual test should be considered for the use in clinical settings to increase uptake of simultaneous testing of HIV and syphilis and accelerate time to treatment for those who need it.

Laboratory Evaluation of a Dual-Path Platform Assay for Rapid Point-of-Care HIV and Syphilis Testing

ABSTRACT We assessed the laboratory performance of the Chembio dual-path platform HIV-syphilis rapid immunodiagnostic test and electronic reader for detection of HIV and Treponema pallidum antibodies in 450 previously characterized serum specimens. For visual or electronic reader HIV antibody detection, the sensitivity was 100% and the specificity was 98.7%. For visual T. pallidum antibody detection, the test sensitivity was 94.7% and the specificity was 100.0%; with the electronic reader, the sensitivity was 94.7% and the specificity was 99.7%.

Field Evaluation of a Dual Rapid Immunodiagnostic Test for HIV and Syphilis Infection in Peru.

Background Integrated prevention for HIV and syphilis is warranted because both syphilis and HIV infections have evidence-based, scalable interventions using current health care mechanisms. The advent of dual rapid point-of-care tests, single devices that can detect multiple infections using the same specimen, provides the opportunity to integrate the screening of syphilis into HIV prevention programs, potentially increasing the numbers of people tested and allowing for same-day testing and treatment. The aim of our study was to evaluate the MedMira Multiplo Rapid TP/HIV Antibody Test (MedMira Inc, Halifax, Nova Scotia, Canada), a qualitative, rapid immunoassay that detects antibodies to Treponema pallidum and HIV. Methods The reference test for comparison to the T. pallidum component of the Multiplo TP/HIV Test was the T. pallidum particle agglutination assay. For the HIV component, the reference test included a fourth-generation enzyme immunoassay with a confirmatory Western blot test. Results The sensitivity and specificity for the HIV antibody component were 93.8% (95% confidence interval [CI], 69.8%–99.8%) and 100% (95% CI, 97.7%–100%), respectively. The T. pallidum component of the test had a sensitivity of 81.0% (95% CI, 68.1%–94.6%) and a specificity of 100% (95% CI, 97.6%–100%). Conclusions Our study showed excellent performance of the HIV antibody component of the test and very good performance for the T. pallidum antibody component of the MedMira Multiplo Rapid TP/HIV Antibody Test, which should be considered to improve screening coverage. Use of effective dual tests will create improved access to more comprehensive care by integrating the screening of syphilis into HIV prevention programs.

High prevalence of extra-genital chlamydial or gonococcal infections among men who have sex with men and transgender women in Lima, Peru

Chlamydia trachomatis and Neisseria gonorrhoeae are among the most common sexually transmitted bacterial infections in the world. Data are limited, however, on the burden of extra-genital chlamydial and gonococcal infections among men who have sex with men and transgender women in Lima, Peru. Data were gathered from self-collected anal or pharyngeal swabs from participants in Lima, Peru, and analyzed via cross-sectional methods. Prevalence ratios for the association between extra-genital infection with socio-demographic and sexual behaviors were determined. Overall, 127 (32.8%) participants had anal or pharyngeal infections. On multivariate modeling, anal infection was positively associated with practicing both receptive and insertive anal sex, when compared to insertive alone (PR = 2.49; 95% CI = 1.32–4.71), and negatively associated with any antibiotic use in the prior three months (PR = 0.60; 95% CI = 0.39–0.91). Pharyngeal infection was negatively associated with age greater than 30 years compared to 18–30 years (PR = 0.54; 95% CI = 0.30–0.96), and positively associated with gender identity of transgender women (PR = 2.12; 95% CI = 1.20–3.73). This study demonstrates considerable burden of extra-genital chlamydial and gonococcal infections among men who have sex with men and transgender women in Lima, Peru.

Treponema pallidum pallidum genotypes and macrolide resistance status in syphilitic lesions among patients at 2 sexually transmitted infection clinics in Lima, Peru

We report the circulating genotypes and the frequency of macrolide-resistance patterns among Treponema pallidum pallidum DNA isolated from syphilitic lesions from patients who attended 2 sexual health clinics in Lima, Peru. We implemented and used a molecular typing scheme to describe local T. pallidum pallidum strains. Among 14 specimens, subtype 14d/f was the most prevalent strain in 7 fully typed T. pallidum DNA specimens obtained from men who have sex with men and transgender women presenting with chancre-like lesions. No macrolide-resistance mutations were found in T. pallidum DNA from 10 lesions.

Laboratory Evaluation of a Point-of-Care Downward-Flow Assay for Simultaneous Detection of Antibodies to Treponema pallidum and Human Immunodeficiency Virus

ABSTRACT Combining the detection of syphilis and HIV antibodies into one point-of-care test integrates syphilis screening into already existing HIV screening programs, which may be particularly beneficial in settings such as antenatal care. Using the INSTI Multiplex downward-flow immunoassay, we tested 200 stored serum samples from high-risk patients enrolled in a longitudinal study on HIV infection and syphilis in Peruvian men who have sex with men and transgender women. This rapid assay detected HIV and Treponema pallidum serum antibodies with sensitivities of 100% (95% confidence interval [CI], 95.9% to 100%) and 87.4% (95% CI, 81.4% to 92.0%), respectively, and specificities of 95.5% (95% CI, 89.9% to 98.5%) and 97.0% (95% CI, 84.2% to 99.9%), respectively (n = 200). The sensitivity for syphilis antibody detection was higher in patients with a rapid plasma reagin titer of ≥1:8 (97.3%) than in those with a titer of ≤1:4 (90%) or a nonreactive titer (66.7%).

Similarities in the Markers of Inflammation Between Men With Syphilis and Women With Increased Risk of HIV Acquisition

TO THE EDITOR—We appreciated the recent study by Masson et al that utilized multiplex bead-based enzyme-linked immunosorbent assays (MBB-ELISAs) to associate human immunodeficiency virus (HIV) seroconversionwith raisedgenital inflammatory cytokines from samples from cervicovaginal lavages from KwaZuluNatal, South Africa [1]. The authors found that several cytokines, including macrophage inflammatory protein 1B, macrophage inflammatory protein 1A, interferon gamma-induced protein 10, and interleukin 8 levels, were elevated in HIV seroconverters compared with nonconverters. We conducted a pilot study using MBB-ELISAs to simultaneously screen for 63 cytokines in sera samples collected from patients with and without syphilis in Lima, Peru. Interestingly our study found elevated levels of similar chemotactic, inflammatory, and hematopoietic cytokines to the ones seen in the study by Masson et al. We found 16 cytokines that were increased (P < .05) in 5 HIV–antibody negative, syphilis-infected (rapid plasma reagin [RPR]≥ 1:32, treponema pallidum particle agglutination assay [TPPA]positive) participants (average age: 32 ± 8.8 years) and 5 HIV–antibody negative, syphilis-negative (RPR non-reactive, TPPA-negative) participants (average age: 35.6 ± 7.9 years). Of those 16 cytokines, 11 were not previously described in the literature as being syphilis associated: interleukin 7 (P = .01), vascular endothelial growth factor D (P = .01), macrophage inflammatory protein 1B (P = .01), interferon gamma-induced protein 10 (P = .02), interleukin 12 active heterodimer (P = .02), leptin (P = .02), monocyte-specific chemokine 3 (P = .02), nerve growth factor (P = .03), eotaxin (P = .04), granulocyte macrophage colony-stimulating factor (P = .04), and platelet-derived growth factor (P = .04) [2–10]. We found increased median fluorescence intensity (MFI) values for all of the 16 cytokines in

Laboratory Evaluation of a Smartphone-Based Electronic Reader of Rapid Dual Point-of-Care Tests for Antibodies to Human Immunodeficiency Virus and Treponema pallidum Infections

Background Dual point-of-care tests for antibodies to human immunodeficiency virus (HIV) and Treponema pallidum allow for same-day testing and treatment and have been demonstrated to be cost-effective in preventing the adverse outcomes of HIV infection and syphilis. By recording and transmitting data as they are collected, electronic readers address challenges related to the decentralization of point-of-care testing. Methods We evaluated a smartphone-based electronic reader using 201 sera tested with 2 dual rapid tests for detection of antibodies to HIV and T. pallidum in Los Angeles, USA, and Lima, Peru. Tests were read both visually and with the electronic reader. Enzyme immunoassay followed by Western blot and T. pallidum particle agglutination were the reference tests for HIV and T. pallidum, respectively. Results The sensitivities of the 2 rapid tests for detection of HIV were 94.1% and 97.0% for electronic readings. Both tests had a specificity of 100% for detection of HIV by electronic reading. The sensitivities of the 2 rapid tests for detection of T. pallidum were 86.5% and 92.4% for electronic readings. The specificities for detection of T. pallidum were 99.1% and 99.0% by electronic reading. There were no significant differences between the accuracies of visual and electronic readings, and the performance did not differ between the 2 study sites. Conclusions Our results show the electronic reader to be a promising option for increasing the use of point-of-care testing programs.

Field evaluation of a smartphone-based electronic reader of rapid dual HIV and syphilis point-of-care immunoassays

Objective Electronic (E) devices read and quantify lateral flow-based rapid tests, providing a novel approach to assay interpretation. We evaluated the performance of one E-reader for two dual HIV and syphilis immunoassays. Methods We enrolled men who have sex with men and transgender women >18 years of age seeking medical services at an STD clinic in Lima, Peru, between October 2016 and April 2017. Venous blood was tested using two dual HIV and syphilis antibody immunoassays (SD BIOLINE HIV/Syphilis Duo, Republic of Korea, and First Response HIV 1+2/Syphilis Combo, India). Reference testing included a fourth-generation ELISA for HIV antibodies and use of the Treponema pallidum particle agglutination assay for syphilis antibodies. Trained clinic staff visually inspected the immunoassay results, after which the immunoassays were read by the HRDR-200 E-reader (Cellmic, USA), an optomechanical smartphone attachment. We calculated the concordance of the E-reader with visual inspection, as well as the sensitivity of both rapid immunoassays, in detecting HIV and T. pallidum antibodies. Results On reference testing of 283 participant specimens, 34% had HIV antibodies and 46% had T. pallidum antibodies. Using First Response, the concordance of the E-reader with visual inspection was 97% (95% CI 94% to 99%) for T . pallidum and 97% (95% CI 95% to 99%) for HIV antibodies. Using SD BIOLINE, the concordance of the E-reader with visual inspection was 97% (95% CI 94% to 99%) for T. pallidum and 99% (95% CI 98% to 99%) for HIV antibodies. For both immunoassays, the sensitivity for HIV antibodies was 98% (95% CI 93% to 100%) and the sensitivity for T. pallidum antibodies was 81% (95% CI 73% to 87%). Conclusions E-reader results correlated well with visual inspection. The sensitivities of both rapid assays were comparable with past reports. Further evaluation of the E-reader is warranted to investigate its utility in data collection, monitoring and documentation of immunoassay results.