The performance of four molecular methods for the laboratory diagnosis of congenital toxoplasmosis in amniotic fluid samples
Introduction Toxoplasmosis may be life-threatening in fetuses and in immune-deficient patients. Conventional laboratory diagnosis of toxoplasmosis is based on the presence of IgM and IgG anti-Toxoplasma gondii antibodies; however, molecular techniques have emerged as alternative tools due to their i...
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ftdoajarticles:oai:doaj.org/article:351068be3df94418a17bdced5e63cbbf 2023-05-15T15:16:01+02:00 The performance of four molecular methods for the laboratory diagnosis of congenital toxoplasmosis in amniotic fluid samples Leandro Emidio Teixeira Kelly Aparecida Kanunfre Paulo Tadashi Shimokawa Lilia Spaleta Targa Jonatas Cristian Rodrigues Wilson Domingues Lidia Yamamoto Thelma Suely Okay 2013-10-01T00:00:00Z https://doi.org/10.1590/0037-8682-0095-2013 https://doaj.org/article/351068be3df94418a17bdced5e63cbbf EN eng Sociedade Brasileira de Medicina Tropical (SBMT) http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0037-86822013000500584&lng=en&tlng=en https://doaj.org/toc/1678-9849 1678-9849 doi:10.1590/0037-8682-0095-2013 https://doaj.org/article/351068be3df94418a17bdced5e63cbbf Revista da Sociedade Brasileira de Medicina Tropical, Vol 46, Iss 5, Pp 584-588 (2013) Congenital toxoplasmosis Congenital infection Molecular diagnosis PCR Quantitative PCR Real-time PCR Arctic medicine. Tropical medicine RC955-962 article 2013 ftdoajarticles https://doi.org/10.1590/0037-8682-0095-2013 2022-12-30T23:10:30Z Introduction Toxoplasmosis may be life-threatening in fetuses and in immune-deficient patients. Conventional laboratory diagnosis of toxoplasmosis is based on the presence of IgM and IgG anti-Toxoplasma gondii antibodies; however, molecular techniques have emerged as alternative tools due to their increased sensitivity. The aim of this study was to compare the performance of 4 PCR-based methods for the laboratory diagnosis of toxoplasmosis. One hundred pregnant women who seroconverted during pregnancy were included in the study. The definition of cases was based on a 12-month follow-up of the infants. Methods Amniotic fluid samples were submitted to DNA extraction and amplification by the following 4 Toxoplasma techniques performed with parasite B1 gene primers: conventional PCR, nested-PCR, multiplex-nested-PCR, and real-time PCR. Seven parameters were analyzed, sensitivity (Se), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR), negative likelihood ratio (NLR) and efficiency (Ef). Results Fifty-nine of the 100 infants had toxoplasmosis; 42 (71.2%) had IgM antibodies at birth but were asymptomatic, and the remaining 17 cases had non-detectable IgM antibodies but high IgG antibody titers that were associated with retinochoroiditis in 8 (13.5%) cases, abnormal cranial ultrasound in 5 (8.5%) cases, and signs/symptoms suggestive of infection in 4 (6.8%) cases. The conventional PCR assay detected 50 cases (9 false-negatives), nested-PCR detected 58 cases (1 false-negative and 4 false-positives), multiplex-nested-PCR detected 57 cases (2 false-negatives), and real-time-PCR detected 58 cases (1 false-negative). Conclusions The real-time PCR assay was the best-performing technique based on the parameters of Se (98.3%), Sp (100%), PPV (100%), NPV (97.6%), PLR (∞), NLR (0.017), and Ef (99%). Article in Journal/Newspaper Arctic Directory of Open Access Journals: DOAJ Articles Arctic Revista da Sociedade Brasileira de Medicina Tropical 46 5 584 588 |
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English |
topic |
Congenital toxoplasmosis Congenital infection Molecular diagnosis PCR Quantitative PCR Real-time PCR Arctic medicine. Tropical medicine RC955-962 |
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Congenital toxoplasmosis Congenital infection Molecular diagnosis PCR Quantitative PCR Real-time PCR Arctic medicine. Tropical medicine RC955-962 Leandro Emidio Teixeira Kelly Aparecida Kanunfre Paulo Tadashi Shimokawa Lilia Spaleta Targa Jonatas Cristian Rodrigues Wilson Domingues Lidia Yamamoto Thelma Suely Okay The performance of four molecular methods for the laboratory diagnosis of congenital toxoplasmosis in amniotic fluid samples |
topic_facet |
Congenital toxoplasmosis Congenital infection Molecular diagnosis PCR Quantitative PCR Real-time PCR Arctic medicine. Tropical medicine RC955-962 |
description |
Introduction Toxoplasmosis may be life-threatening in fetuses and in immune-deficient patients. Conventional laboratory diagnosis of toxoplasmosis is based on the presence of IgM and IgG anti-Toxoplasma gondii antibodies; however, molecular techniques have emerged as alternative tools due to their increased sensitivity. The aim of this study was to compare the performance of 4 PCR-based methods for the laboratory diagnosis of toxoplasmosis. One hundred pregnant women who seroconverted during pregnancy were included in the study. The definition of cases was based on a 12-month follow-up of the infants. Methods Amniotic fluid samples were submitted to DNA extraction and amplification by the following 4 Toxoplasma techniques performed with parasite B1 gene primers: conventional PCR, nested-PCR, multiplex-nested-PCR, and real-time PCR. Seven parameters were analyzed, sensitivity (Se), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR), negative likelihood ratio (NLR) and efficiency (Ef). Results Fifty-nine of the 100 infants had toxoplasmosis; 42 (71.2%) had IgM antibodies at birth but were asymptomatic, and the remaining 17 cases had non-detectable IgM antibodies but high IgG antibody titers that were associated with retinochoroiditis in 8 (13.5%) cases, abnormal cranial ultrasound in 5 (8.5%) cases, and signs/symptoms suggestive of infection in 4 (6.8%) cases. The conventional PCR assay detected 50 cases (9 false-negatives), nested-PCR detected 58 cases (1 false-negative and 4 false-positives), multiplex-nested-PCR detected 57 cases (2 false-negatives), and real-time-PCR detected 58 cases (1 false-negative). Conclusions The real-time PCR assay was the best-performing technique based on the parameters of Se (98.3%), Sp (100%), PPV (100%), NPV (97.6%), PLR (∞), NLR (0.017), and Ef (99%). |
format |
Article in Journal/Newspaper |
author |
Leandro Emidio Teixeira Kelly Aparecida Kanunfre Paulo Tadashi Shimokawa Lilia Spaleta Targa Jonatas Cristian Rodrigues Wilson Domingues Lidia Yamamoto Thelma Suely Okay |
author_facet |
Leandro Emidio Teixeira Kelly Aparecida Kanunfre Paulo Tadashi Shimokawa Lilia Spaleta Targa Jonatas Cristian Rodrigues Wilson Domingues Lidia Yamamoto Thelma Suely Okay |
author_sort |
Leandro Emidio Teixeira |
title |
The performance of four molecular methods for the laboratory diagnosis of congenital toxoplasmosis in amniotic fluid samples |
title_short |
The performance of four molecular methods for the laboratory diagnosis of congenital toxoplasmosis in amniotic fluid samples |
title_full |
The performance of four molecular methods for the laboratory diagnosis of congenital toxoplasmosis in amniotic fluid samples |
title_fullStr |
The performance of four molecular methods for the laboratory diagnosis of congenital toxoplasmosis in amniotic fluid samples |
title_full_unstemmed |
The performance of four molecular methods for the laboratory diagnosis of congenital toxoplasmosis in amniotic fluid samples |
title_sort |
performance of four molecular methods for the laboratory diagnosis of congenital toxoplasmosis in amniotic fluid samples |
publisher |
Sociedade Brasileira de Medicina Tropical (SBMT) |
publishDate |
2013 |
url |
https://doi.org/10.1590/0037-8682-0095-2013 https://doaj.org/article/351068be3df94418a17bdced5e63cbbf |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic |
genre_facet |
Arctic |
op_source |
Revista da Sociedade Brasileira de Medicina Tropical, Vol 46, Iss 5, Pp 584-588 (2013) |
op_relation |
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0037-86822013000500584&lng=en&tlng=en https://doaj.org/toc/1678-9849 1678-9849 doi:10.1590/0037-8682-0095-2013 https://doaj.org/article/351068be3df94418a17bdced5e63cbbf |
op_doi |
https://doi.org/10.1590/0037-8682-0095-2013 |
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Revista da Sociedade Brasileira de Medicina Tropical |
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