Detection of Giardia duodenalis assemblages A and B in human feces by simple, assemblage-specific PCR assays.

The flagellated protozoan Giardia duodenalis is a common gastrointestinal parasite of mammals, including humans. Molecular characterizations have shown the existence of eight genetic groups (or assemblages) in the G. duodenalis species complex. Human infections are caused by assemblages A and B, whi...

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Main Authors: Ilaria Vanni, Simone Mario Cacciò, Lindy van Lith, Marianne Lebbad, Staffan G Svärd, Edoardo Pozio, Fabio Tosini
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2012-01-01
Series:PLoS Neglected Tropical Diseases
Online Access:https://journals.plos.org/plosntds/article/file?id=10.1371/journal.pntd.0001776&type=printable
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author Ilaria Vanni
Simone Mario Cacciò
Lindy van Lith
Marianne Lebbad
Staffan G Svärd
Edoardo Pozio
Fabio Tosini
author_facet Ilaria Vanni
Simone Mario Cacciò
Lindy van Lith
Marianne Lebbad
Staffan G Svärd
Edoardo Pozio
Fabio Tosini
author_sort Ilaria Vanni
collection DOAJ
description The flagellated protozoan Giardia duodenalis is a common gastrointestinal parasite of mammals, including humans. Molecular characterizations have shown the existence of eight genetic groups (or assemblages) in the G. duodenalis species complex. Human infections are caused by assemblages A and B, which infect other mammals as well. Whether transmission routes, animal reservoirs and associations with specific symptoms differ for assemblage A and assemblage B is not clear. Furthermore, the occurrence and clinical significance of mixed (A+B) infections is also poorly understood. To date, the majority of PCR assays has been developed to identify all G. duodenalis assemblages based on the use of primers that bind to conserved regions, yet a reliable identification of specific assemblages is better achieved by ad hoc methods. The aim of this work was to design simple PCR assays that, based on the use of assemblage-specific primers, produce diagnostic bands of different lengths for assemblage A and B. We first generated novel sequence information from assemblage B, identified homologous sequences in the assemblage A genome, and designed primers at six independent loci. Experiments performed on DNA extracted from axenic cultures showed that two of the six assays can detect the equivalent of a single cyst and are not negatively influenced by disproportions between DNA of each assemblage, at least up to a 9:1 ratio. Further experiments on DNAs extracted from feces showed that the two assays can detect both assemblages in single tube reactions with excellent reliability. Finally, the robustness of these assays was demonstrated by testing a large collection of human isolates previously typed by multi-locus genotyping.
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spelling doaj-art-90f4c0fd675545b09fa8a25a3986af9b2025-08-20T03:01:13ZengPublic Library of Science (PLoS)PLoS Neglected Tropical Diseases1935-27271935-27352012-01-0168e177610.1371/journal.pntd.0001776Detection of Giardia duodenalis assemblages A and B in human feces by simple, assemblage-specific PCR assays.Ilaria VanniSimone Mario CacciòLindy van LithMarianne LebbadStaffan G SvärdEdoardo PozioFabio TosiniThe flagellated protozoan Giardia duodenalis is a common gastrointestinal parasite of mammals, including humans. Molecular characterizations have shown the existence of eight genetic groups (or assemblages) in the G. duodenalis species complex. Human infections are caused by assemblages A and B, which infect other mammals as well. Whether transmission routes, animal reservoirs and associations with specific symptoms differ for assemblage A and assemblage B is not clear. Furthermore, the occurrence and clinical significance of mixed (A+B) infections is also poorly understood. To date, the majority of PCR assays has been developed to identify all G. duodenalis assemblages based on the use of primers that bind to conserved regions, yet a reliable identification of specific assemblages is better achieved by ad hoc methods. The aim of this work was to design simple PCR assays that, based on the use of assemblage-specific primers, produce diagnostic bands of different lengths for assemblage A and B. We first generated novel sequence information from assemblage B, identified homologous sequences in the assemblage A genome, and designed primers at six independent loci. Experiments performed on DNA extracted from axenic cultures showed that two of the six assays can detect the equivalent of a single cyst and are not negatively influenced by disproportions between DNA of each assemblage, at least up to a 9:1 ratio. Further experiments on DNAs extracted from feces showed that the two assays can detect both assemblages in single tube reactions with excellent reliability. Finally, the robustness of these assays was demonstrated by testing a large collection of human isolates previously typed by multi-locus genotyping.https://journals.plos.org/plosntds/article/file?id=10.1371/journal.pntd.0001776&type=printable
spellingShingle Ilaria Vanni
Simone Mario Cacciò
Lindy van Lith
Marianne Lebbad
Staffan G Svärd
Edoardo Pozio
Fabio Tosini
Detection of Giardia duodenalis assemblages A and B in human feces by simple, assemblage-specific PCR assays.
PLoS Neglected Tropical Diseases
title Detection of Giardia duodenalis assemblages A and B in human feces by simple, assemblage-specific PCR assays.
title_full Detection of Giardia duodenalis assemblages A and B in human feces by simple, assemblage-specific PCR assays.
title_fullStr Detection of Giardia duodenalis assemblages A and B in human feces by simple, assemblage-specific PCR assays.
title_full_unstemmed Detection of Giardia duodenalis assemblages A and B in human feces by simple, assemblage-specific PCR assays.
title_short Detection of Giardia duodenalis assemblages A and B in human feces by simple, assemblage-specific PCR assays.
title_sort detection of giardia duodenalis assemblages a and b in human feces by simple assemblage specific pcr assays
url https://journals.plos.org/plosntds/article/file?id=10.1371/journal.pntd.0001776&type=printable
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