Techniques for the detection of pathogenic Cryptococcus species in wood decay substrata and the evaluation of viability in stored samples

In this study, we evaluated several techniques for the detection of the yeast form of Cryptococcus in decaying wood and measured the viability of these fungi in environmental samples stored in the laboratory. Samples were collected from a tree known to be positive for Cryptococcus and were each inoc...

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Main Authors: Christian Alvarez, Glaucia Gonçalves Barbosa, Raquel de Vasconcellos Carvalhaes de Oliveira, Bernardina Penarrieta Morales, Bodo Wanke, Márcia dos Santos Lazéra
Format: Article
Language:English
Published: Fundação Oswaldo Cruz (FIOCRUZ) 2013-02-01
Series:Memorias do Instituto Oswaldo Cruz
Subjects:
Online Access:http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0074-02762013000100023&lng=en&tlng=en
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author Christian Alvarez
Glaucia Gonçalves Barbosa
Raquel de Vasconcellos Carvalhaes de Oliveira
Bernardina Penarrieta Morales
Bodo Wanke
Márcia dos Santos Lazéra
author_facet Christian Alvarez
Glaucia Gonçalves Barbosa
Raquel de Vasconcellos Carvalhaes de Oliveira
Bernardina Penarrieta Morales
Bodo Wanke
Márcia dos Santos Lazéra
author_sort Christian Alvarez
collection DOAJ
description In this study, we evaluated several techniques for the detection of the yeast form of Cryptococcus in decaying wood and measured the viability of these fungi in environmental samples stored in the laboratory. Samples were collected from a tree known to be positive for Cryptococcus and were each inoculated on 10 Niger seed agar (NSA) plates. The conventional technique (CT) yielded a greater number of positive samples and indicated a higher fungal density [in colony forming units per gram of wood (CFU.g-1)] compared to the humid swab technique (ST). However, the difference in positive and false negative results between the CT-ST was not significant. The threshold of detection for the CT was 0.05.10³ CFU.g-1, while the threshold for the ST was greater than 0.1.10³ CFU-1. No colonies were recovered using the dry swab technique. We also determined the viability of Cryptococcus in wood samples stored for 45 days at 25ºC using the CT and ST and found that samples not only continued to yield a positive response, but also exhibited an increase in CFU.g-1, suggesting that Cryptococcus is able to grow in stored environmental samples. The ST.1, in which samples collected with swabs were immediately plated on NSA medium, was more efficient and less laborious than either the CT or ST and required approximately 10 min to perform; however, additional studies are needed to validate this technique.
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spelling doaj.art-69cb25cfccf546df8ec893c5898bde692023-09-02T16:26:09ZengFundação Oswaldo Cruz (FIOCRUZ)Memorias do Instituto Oswaldo Cruz1678-80602013-02-01108112612910.1590/S0074-02762013000100023S0074-02762013000100023Techniques for the detection of pathogenic Cryptococcus species in wood decay substrata and the evaluation of viability in stored samplesChristian Alvarez0Glaucia Gonçalves Barbosa1Raquel de Vasconcellos Carvalhaes de Oliveira2Bernardina Penarrieta Morales3Bodo Wanke4Márcia dos Santos Lazéra5Hospital del Niño JesúsFiocruzFiocruzFiocruzFiocruzFiocruzIn this study, we evaluated several techniques for the detection of the yeast form of Cryptococcus in decaying wood and measured the viability of these fungi in environmental samples stored in the laboratory. Samples were collected from a tree known to be positive for Cryptococcus and were each inoculated on 10 Niger seed agar (NSA) plates. The conventional technique (CT) yielded a greater number of positive samples and indicated a higher fungal density [in colony forming units per gram of wood (CFU.g-1)] compared to the humid swab technique (ST). However, the difference in positive and false negative results between the CT-ST was not significant. The threshold of detection for the CT was 0.05.10³ CFU.g-1, while the threshold for the ST was greater than 0.1.10³ CFU-1. No colonies were recovered using the dry swab technique. We also determined the viability of Cryptococcus in wood samples stored for 45 days at 25ºC using the CT and ST and found that samples not only continued to yield a positive response, but also exhibited an increase in CFU.g-1, suggesting that Cryptococcus is able to grow in stored environmental samples. The ST.1, in which samples collected with swabs were immediately plated on NSA medium, was more efficient and less laborious than either the CT or ST and required approximately 10 min to perform; however, additional studies are needed to validate this technique.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0074-02762013000100023&lng=en&tlng=enisolation techniquesCryptococcus neoformansCryptococcus gattiiwood decay substrata
spellingShingle Christian Alvarez
Glaucia Gonçalves Barbosa
Raquel de Vasconcellos Carvalhaes de Oliveira
Bernardina Penarrieta Morales
Bodo Wanke
Márcia dos Santos Lazéra
Techniques for the detection of pathogenic Cryptococcus species in wood decay substrata and the evaluation of viability in stored samples
Memorias do Instituto Oswaldo Cruz
isolation techniques
Cryptococcus neoformans
Cryptococcus gattii
wood decay substrata
title Techniques for the detection of pathogenic Cryptococcus species in wood decay substrata and the evaluation of viability in stored samples
title_full Techniques for the detection of pathogenic Cryptococcus species in wood decay substrata and the evaluation of viability in stored samples
title_fullStr Techniques for the detection of pathogenic Cryptococcus species in wood decay substrata and the evaluation of viability in stored samples
title_full_unstemmed Techniques for the detection of pathogenic Cryptococcus species in wood decay substrata and the evaluation of viability in stored samples
title_short Techniques for the detection of pathogenic Cryptococcus species in wood decay substrata and the evaluation of viability in stored samples
title_sort techniques for the detection of pathogenic cryptococcus species in wood decay substrata and the evaluation of viability in stored samples
topic isolation techniques
Cryptococcus neoformans
Cryptococcus gattii
wood decay substrata
url http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0074-02762013000100023&lng=en&tlng=en
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