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Evaluation of a genus-specific rGroEL_1-524 IgM-ELISA and commercial ELISA kits during the course of leptospirosis in Thailand.

ABSTRACT: In the present study, we developed a genus-specific rGroEL_1-524 IgM-ELISA assay for use in screening diagnosis of suspected leptospirosis among acute undifferentiated febrile illness patients during acute fever. The diagnostic accuracies of the rGroEL_1-524 IgM-ELISA, commercial Panbio IgM-ELISA, and Virion-Serion Classic IgG-ELISA were evaluated using 133 Thai leptospirosis sera and 210 controls. Sensitivities were 91.7%, 59.6%, and 17.7% for acute infection, and the specificities were 92.6%, 90.2%, and 88.3% for the non-leptospirosis control, respectively. The rGroEL_1-524 IgM-ELISA had high sensitivity, at 92.3% and 91.7%, among culture-positive and MAT-negative cases at 1-3 days post-onset of symptoms (DPO1-3), respectively. Impaired specificity on scrub typhus was found, possibly from antibody cross-reaction to ortholog GroEL. Commercial Panbio IgM-ELISA had sensitivities at DPO1-3 of 30.8% and 41.7% for culture-positive and MAT-negative cases whereas Virion-Serion IgG-ELISA showed sensitivities of 5.9% and 13.3%, respectively. The rGroEL_1-524 IgM-ELISA could be useful as a screening test for early diagnosis. The performance of the commercial ELISA suggests the applicability of IgM-ELISA for diagnosis, while IgG-ELISA is useful for seroprevalence surveys. However, confirmation by reference tests is recommended.

SUBMITTER: Maneewatchararangsri S

PROVIDER: S-EPMC8492722 | biostudies-literature | 2021 Oct

REPOSITORIES: biostudies-literature

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Evaluation of a genus-specific rGroEL1-524 IgM-ELISA and commercial ELISA kits during the course of leptospirosis in Thailand.

Maneewatchararangsri Santi S Doungchawee Galayanee G Kalambaheti Thareerat T Luvira Viravarn V Soonthornworasiri Ngamphol N Vattanatham Pisut P Chaisri Urai U Adisakwattana Poom P

Scientific reports 20211005 1

In the present study, we developed a genus-specific rGroEL1-524 IgM-ELISA assay for use in screening diagnosis of suspected leptospirosis among acute undifferentiated febrile illness patients during acute fever. The diagnostic accuracies of the rGroEL1-524 IgM-ELISA, commercial Panbio IgM-ELISA, and Virion-Serion Classic IgG-ELISA were evaluated using 133 Thai leptospirosis sera and 210 controls. Sensitivities were 91.7%, 59.6%, and 17.7% for acute infection, and the specif ...[more]

PMID: 34611273

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Project description:BackgroundLeptospirosis is diagnosed on clinical grounds, and confirmed by microscopic agglutination test (MAT). IgM-ELISA (Serion-Virion) and immunochromatography test (Leptocheck-WB) are two immunodiagnostic assays for leptospirosis. Their sensitivity, specificity and applicability in Sri Lanka have not been systematically evaluated.MethodsClinically diagnosed leptospirosis patients (n = 919) were recruited from three hospitals in the Western Province of Sri Lanka, during June 2012 to December 2013. MAT, IgM-ELISA and Leptocheck-WB were performed on all patient sera. MAT titer of ≥ 400 in single sample, four-fold rise or seroconversion ≥ 100 in paired samples were considered as positive for MAT. For diagnostic confirmation, MAT was performed during both acute and convalescent phases. Anti-leptospiral IgM ≥ 20 IU/ml and appearance of a band in the test window were considered as positive for IgM-ELISA and Leptocheck-WB test respectively. Patients with an alternative diagnosis (n = 31) were excluded. Data analysis was performed using two methods, i) considering MAT as reference standard and ii) using Bayesian latent class model analysis (BLCM) which considers each test as imperfect.ResultsMAT, IgM-ELISA and Leptocheck-WB positivity were 39.8%, 45.8% and 38.7% respectively during the acute phase. Acute-phase MAT had specificity and sensitivity of 95.7% and 55.3% respectively, when compared to overall MAT positivity. IgM-ELISA and Leptocheck-WB had similar diagnostic sensitivity when compared with acute-phase MAT as the gold standard, although IgM-ELISA showed higher specificity (84.5%) than Leptocheck-WB (73.3%). BLCM analysis showed that IgM-ELISA and Leptocheck-WB had similar sensitivities (86.0% and 87.4%), while acute-phase MAT had the lowest sensitivity (77.4%). However, acute-phase MAT had high specificity (97.6%), while IgM-ELISA and Leptocheck-WB showed similar but lower specificity (84.5% and 82.9%).ConclusionsBoth IgM-ELISA and Leptocheck-WB shows similar sensitivities and specificities. IgM-ELISA may be superior to MAT during the acute phase and suitable for early diagnosis of leptospirosis. Leptocheck-WB is suitable as a rapid immunodiagnostic screening test for resource limited settings.

Project description:Background: Antimalarial antibody measurements are useful because they reflect historical and recent exposure to malaria. As such, they may provide additional information to assess ongoing transmission in low endemic or pre-elimination settings where cases are rare. In addition, the absence of antibody responses in certain individuals can indicate the cessation of transmission. Commercial malaria enzyme-linked immunosorbent assays (ELISA) detect antimalarial antibodies and are commonly used to screen blood donations for possible malaria infection. However, there is no standardized test to detect antimalarial antibodies for epidemiological use. Here we compared five commercially available ELISA kits (Trinity Biotech, newbio, DiaPro, Cellabs, and NovaTec) in search of a standardized tool for supporting claims of absence of malaria transmission. For comparison, a research-based (RB) ELISA protocol was performed alongside the commercial kits. Results: The commercial kits were first compared using serum samples from known malaria-unexposed individuals (n = 223) and Toxoplasma-infected individuals (n = 191) to assess specificity and cross-reactivity against non-malaria infections. In addition, 134 samples from ≥10-year-olds collected in a hyperendemic region in the Gambia in the early 1990s were used to assess sensitivity. Three out of five kits showed high sensitivity (90-92%), high specificity (98-99%), low cross-reactivity (0-3%) and were considered user-friendly (Trinity Biotech, newbio and NovaTec). Two of these kits (Trinity Biotech and NovaTec) were taken forward for epidemiological evaluation and results were compared to those using the RB-ELISA. Samples from two pre-elimination settings (Praia, Cape Verde; n = 1,396, and Bataan, the Philippines; n = 1,824) were tested. Serological results from both the Trinity Biotech kit and the RB-ELISA concurred with recent passively detected case counts in both settings. Results from the Trinity Biotech kit reflected a significant decrease in the number of reported cases in Bataan in the 1990s better than the RB-ELISA. Results from the NovaTec kit did not reflect transmission patterns in either setting. Conclusion: The Trinity Biotech commercial ELISA kit was considered reliable for epidemiological use and accurately described transmission patterns in two (previously) malaria endemic settings. The use of this simple and standardized serological tool may aid national control and elimination programs by confirming that regions are free from malaria.

Project description:BackgroundLeptospirosis is an important but largely under-recognized public health problem in the tropics. Establishment of highly sensitive and specific laboratory diagnosis is essential to reveal the magnitude of problem and to improve treatment. This study aimed to evaluate the diagnostic accuracy of a recombinant LigA protein based IgM ELISA during outbreaks in the clinical-setting of a highly endemic country.Methodology/principal findingsA prospective study was conducted from October 2011 to September 2013 at a national referral hospital for infectious diseases in Manila, Philippines. Patients who were hospitalized with clinically suspected leptospirosis were enrolled. Plasma and urine were collected on admission and/or at discharge and tested using the LigA-IgM ELISA and a whole cell-based IgM ELISA. Sensitivity and specificity of these tests were evaluated with cases diagnosed by microscopic agglutination test (MAT), culture and LAMP as the composite reference standard and blood bank donors as healthy controls: the mean+3 standard deviation optical density value of healthy controls was used as the cut-off limit (0.062 for the LigA-IgM ELISA and 0.691 for the whole cell-based IgM ELISA). Of 304 patients enrolled in the study, 270 (89.1%) were male and the median age was 30.5 years; 167 (54.9%) were laboratory confirmed. The sensitivity and ROC curve AUC for the LigA-IgM ELISA was significantly greater than the whole cell-based IgM ELISA (69.5% vs. 54.3%, p<0.01; 0.90 vs. 0.82, p<0.01) on admission, but not at discharge. The specificity of LigA-IgM ELISA and whole cell-based IgM ELISA were not significantly different (98% vs. 97%). Among 158 MAT negative patients, 53 and 28 were positive by LigA- and whole cell-based IgM ELISA, respectively; if the laboratory confirmation was re-defined by LigA-IgM ELISA and LAMP, the clinical findings were more characteristic of leptospirosis than the diagnosis based on MAT/culture/LAMP.Conclusions/significanceThe newly developed LigA-IgM ELISA is more sensitive than the whole cell-based IgM based ELISA. Although the final diagnosis must be validated by more specific tests, LigA-IgM ELISA could be a useful diagnostic test in a real clinical-setting, where diagnosis is needed in the early phase of infection.

Project description:BackgroundTransfusion with Plasmodium-infected blood represents a risk for malaria transmission, a rare but severe event. Several non-endemic countries implement a strategy for the screening of candidate blood donors including questionnaire for the identification of at-risk subjects and laboratory testing of blood samples, often serology-based, with temporary deferral from donation for individuals with a positive result. In Italy, the most recent legislation, issued in November 2015, introduced the use of serological tests for the detection of anti-Plasmodium antibodies.MethodsIn the absence of a gold standard for malaria serology, the aim of this work was to evaluate five commercial ELISA kits, and to determine their accuracy (sensitivity and specificity) in comparison to immuno-fluorescence antibody test (IFAT), and their agreement (concordance of results). Serum samples from malaria patients or from subjects with malaria history (N = 64), malaria naïve patients with other parasitic infections (N = 15), malaria naïve blood donors (N = 8) and malaria exposed candidate blood donors (N = 36) were tested.ResultsThe specificity of all ELISA kits was 100%, while sensitivity ranged between 53 and 64% when compared to IFAT on malaria patients samples. When tested on candidate blood donors' samples, ELISA kits showed highly variable agreement (42-94%) raising the possibility that the same individual could be included or excluded from donation depending on the test in use by the transfusion centre.ConclusionsThese preliminary results indicate how the lack of a gold standard for malaria serology must be taken into account in the application and future revision of current legislation. There is need of developing more sensitive serological assays. Moreover, the adoption of a unique serological test at national level is recommended, as well as the development of screening algorithms based on multiple laboratory tests, including molecular assays.

Project description:Cytauxzoonosis is a tick-borne infectious disease affecting domestic cats with high mortality and limited treatment modalities. Because early diagnosis and therapeutic intervention are crucial to survival of infected cats, the objective of this study was to develop an ELISA capable of detecting cytauxzoonosis and differentiating acute vs. chronic infection in clinical feline blood samples. A microsphere immunoassay (MIA) was developed to evaluate the production of Cytauxzoon felis-specific IgM and IgG antibodies in serial plasma samples from cats with experimental C. felis infection by targeting a C. felis-specific transmembrane protein (c88). Recombinant c88 protein was utilized to develop indirect ELISAs to detect IgM and IgG antibodies in clinical plasma samples from: PCR-positive cats with acute C. felis infection (n = 36), C. felis-negative cats with pyrexia (n = 10), healthy C. felis-negative cats (n = 22), and chronic C. felis carriers (n = 4). Anti-c88 IgM antibodies were detectable at day 12 post-tick infestation in cats with experimental C. felis infection (within 24 hours of developing clinical signs), while anti-c88 IgG was detectable at day 15 post-tick infestation - indicating IgM could be used to detect early infection. Using a cut-off value of 19.85 percent positive, the C. felis IgM ELISA detected acute cytauxzoonosis in 94.44% (34/36) of cats presented with clinical signs of acute cytauxzoonosis with 100% specificity (indicating a "Strong Positive" result). When a lower cutoff of 8.60 percent positive was used, cytauxzoonosis was detected in the 2 remaining PCR-positive cats with 87.88% specificity (indicating of a "Weak Positive" result). One C. felis-negative, febrile cat had high IgG, and chronic carriers had variable IgM and IgG results. Combined interpretation of IgM and IgG ELISAs did not reliably differentiate acute vs. chronic infection. While further validation on assay performance is needed, the C. felis IgM ELISA is a promising test to detect acute cytauxzoonosis and can be utilized to develop a point-of-care test for clinical use.

Dataset Information

Evaluation of a genus-specific rGroEL_1-524 IgM-ELISA and commercial ELISA kits during the course of leptospirosis in Thailand.

Publications

Evaluation of a genus-specific rGroEL<sub>1-524</sub> IgM-ELISA and commercial ELISA kits during the course of leptospirosis in Thailand.

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