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Evaluation of conventional and four real-time PCR methods for the detection of Leishmania on field-collected samples in Ethiopia
In most low-resource settings, microscopy still is the standard method for diagnosis of cutaneous leishmaniasis, despite its limited sensitivity. In Ethiopia, the more sensitive molecular methods are not yet routinely used. This study compared five PCR methods with microscopy on two sample types col...
Autores principales: | , , , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2021
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7802924/ https://www.ncbi.nlm.nih.gov/pubmed/33434190 http://dx.doi.org/10.1371/journal.pntd.0008903 |
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author | Merdekios, Behailu Pareyn, Myrthe Tadesse, Dagimawie Eligo, Nigatu Kassa, Mekibib Jacobs, Bart K. M. Leirs, Herwig Van Geertruyden, Jean-Pierre van Griensven, Johan Caljon, Guy Cnops, Lieselotte |
author_facet | Merdekios, Behailu Pareyn, Myrthe Tadesse, Dagimawie Eligo, Nigatu Kassa, Mekibib Jacobs, Bart K. M. Leirs, Herwig Van Geertruyden, Jean-Pierre van Griensven, Johan Caljon, Guy Cnops, Lieselotte |
author_sort | Merdekios, Behailu |
collection | PubMed |
description | In most low-resource settings, microscopy still is the standard method for diagnosis of cutaneous leishmaniasis, despite its limited sensitivity. In Ethiopia, the more sensitive molecular methods are not yet routinely used. This study compared five PCR methods with microscopy on two sample types collected from patients with a suspected lesion to advise on optimal diagnosis of Leishmania aethiopica. Between May and July 2018, skin scrapings (SS) and blood exudate from the lesion spotted on filter paper (dry blood spot, DBS) were collected for PCR from 111 patients of four zones in Southern Ethiopia. DNA and RNA were simultaneously extracted from both sample types. DNA was evaluated by a conventional PCR targeting ITS-1 and three probe-based real-time PCRs: one targeting the SSU 18S rRNA and two targeting the kDNA minicircle sequence (the ‘Mary kDNA PCR’ and a newly designed ‘LC kDNA PCR’ for improved L. aethiopica detection). RNAs were tested with a SYBR Green-based RT-PCR targeting spliced leader (SL) RNA. Giemsa-stained SS smears were examined by microscopy. Of the 111 SS, 100 were positive with at least two methods. Sensitivity of microscopy, ITS PCR, SSU PCR, Mary kDNA PCR, LC kDNA PCR and SL RNA PCR were respectively 52%, 22%, 64%, 99%, 100% and 94%. Microscopy-based parasite load correlated well with real-time PCR Ct-values. Despite suboptimal sample storage for RNA detection, the SL RNA PCR resulted in congruent results with low Ct-values. DBS collected from the same lesion showed lower PCR positivity rates compared to SS. The kDNA PCRs showed excellent performance for diagnosis of L. aethiopica on SS. Lower-cost SL RNA detection can be a complementary high-throughput tool. DBS can be used for PCR in case microscopy is negative, the SS sample can be sent to the referral health facility where kDNA PCR method is available. |
format | Online Article Text |
id | pubmed-7802924 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-78029242021-01-22 Evaluation of conventional and four real-time PCR methods for the detection of Leishmania on field-collected samples in Ethiopia Merdekios, Behailu Pareyn, Myrthe Tadesse, Dagimawie Eligo, Nigatu Kassa, Mekibib Jacobs, Bart K. M. Leirs, Herwig Van Geertruyden, Jean-Pierre van Griensven, Johan Caljon, Guy Cnops, Lieselotte PLoS Negl Trop Dis Research Article In most low-resource settings, microscopy still is the standard method for diagnosis of cutaneous leishmaniasis, despite its limited sensitivity. In Ethiopia, the more sensitive molecular methods are not yet routinely used. This study compared five PCR methods with microscopy on two sample types collected from patients with a suspected lesion to advise on optimal diagnosis of Leishmania aethiopica. Between May and July 2018, skin scrapings (SS) and blood exudate from the lesion spotted on filter paper (dry blood spot, DBS) were collected for PCR from 111 patients of four zones in Southern Ethiopia. DNA and RNA were simultaneously extracted from both sample types. DNA was evaluated by a conventional PCR targeting ITS-1 and three probe-based real-time PCRs: one targeting the SSU 18S rRNA and two targeting the kDNA minicircle sequence (the ‘Mary kDNA PCR’ and a newly designed ‘LC kDNA PCR’ for improved L. aethiopica detection). RNAs were tested with a SYBR Green-based RT-PCR targeting spliced leader (SL) RNA. Giemsa-stained SS smears were examined by microscopy. Of the 111 SS, 100 were positive with at least two methods. Sensitivity of microscopy, ITS PCR, SSU PCR, Mary kDNA PCR, LC kDNA PCR and SL RNA PCR were respectively 52%, 22%, 64%, 99%, 100% and 94%. Microscopy-based parasite load correlated well with real-time PCR Ct-values. Despite suboptimal sample storage for RNA detection, the SL RNA PCR resulted in congruent results with low Ct-values. DBS collected from the same lesion showed lower PCR positivity rates compared to SS. The kDNA PCRs showed excellent performance for diagnosis of L. aethiopica on SS. Lower-cost SL RNA detection can be a complementary high-throughput tool. DBS can be used for PCR in case microscopy is negative, the SS sample can be sent to the referral health facility where kDNA PCR method is available. Public Library of Science 2021-01-12 /pmc/articles/PMC7802924/ /pubmed/33434190 http://dx.doi.org/10.1371/journal.pntd.0008903 Text en © 2021 Merdekios et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. |
spellingShingle | Research Article Merdekios, Behailu Pareyn, Myrthe Tadesse, Dagimawie Eligo, Nigatu Kassa, Mekibib Jacobs, Bart K. M. Leirs, Herwig Van Geertruyden, Jean-Pierre van Griensven, Johan Caljon, Guy Cnops, Lieselotte Evaluation of conventional and four real-time PCR methods for the detection of Leishmania on field-collected samples in Ethiopia |
title | Evaluation of conventional and four real-time PCR methods for the detection of Leishmania on field-collected samples in Ethiopia |
title_full | Evaluation of conventional and four real-time PCR methods for the detection of Leishmania on field-collected samples in Ethiopia |
title_fullStr | Evaluation of conventional and four real-time PCR methods for the detection of Leishmania on field-collected samples in Ethiopia |
title_full_unstemmed | Evaluation of conventional and four real-time PCR methods for the detection of Leishmania on field-collected samples in Ethiopia |
title_short | Evaluation of conventional and four real-time PCR methods for the detection of Leishmania on field-collected samples in Ethiopia |
title_sort | evaluation of conventional and four real-time pcr methods for the detection of leishmania on field-collected samples in ethiopia |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7802924/ https://www.ncbi.nlm.nih.gov/pubmed/33434190 http://dx.doi.org/10.1371/journal.pntd.0008903 |
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