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Growth inhibition and ultrastructural alterations induced by Δ(24(25))-sterol methyltransferase inhibitors in Candida spp. isolates, including non-albicans organisms

BACKGROUND: Although Candida species are commensal microorganisms, they can cause many invasive fungal infections. In addition, antifungal resistance can contribute to failure of treatment. The purpose of this study was to evaluate the antifungal activity of inhibitors of Δ(24(25))-sterol methyltran...

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Autores principales: Ishida, Kelly, Rodrigues, Juliany Cola Fernandes, Ribeiro, Marcos Dornelas, Vila, Taíssa Vieira Machado, de Souza, Wanderley, Urbina, Julio A, Nakamura, Celso Vataru, Rozental, Sonia
Formato: Texto
Lenguaje:English
Publicado: BioMed Central 2009
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2679025/
https://www.ncbi.nlm.nih.gov/pubmed/19379501
http://dx.doi.org/10.1186/1471-2180-9-74
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author Ishida, Kelly
Rodrigues, Juliany Cola Fernandes
Ribeiro, Marcos Dornelas
Vila, Taíssa Vieira Machado
de Souza, Wanderley
Urbina, Julio A
Nakamura, Celso Vataru
Rozental, Sonia
author_facet Ishida, Kelly
Rodrigues, Juliany Cola Fernandes
Ribeiro, Marcos Dornelas
Vila, Taíssa Vieira Machado
de Souza, Wanderley
Urbina, Julio A
Nakamura, Celso Vataru
Rozental, Sonia
author_sort Ishida, Kelly
collection PubMed
description BACKGROUND: Although Candida species are commensal microorganisms, they can cause many invasive fungal infections. In addition, antifungal resistance can contribute to failure of treatment. The purpose of this study was to evaluate the antifungal activity of inhibitors of Δ(24(25))-sterol methyltransferase (24-SMTI), 20-piperidin-2-yl-5α-pregnan-3β-20(R)-diol (AZA), and 24(R,S),25-epiminolanosterol (EIL), against clinical isolates of Candida spp., analysing the ultrastructural changes. RESULTS: AZA and EIL were found to be potent growth inhibitors of Candida spp. isolates. The median MIC(50 )was 0.5 μg.ml(-1 )for AZA and 2 μg.ml(-1 )for EIL, and the MIC(90 )was 2 μg.ml(-1 )for both compounds. All strains used in this study were susceptible to amphotericin B; however, some isolates were fluconazole- and itraconazole-resistant. Most of the azole-resistant isolates were Candida non-albicans (CNA) species, but several of them, such as C. guilliermondii, C. zeylanoides, and C. lipolytica, were susceptible to 24-SMTI, indicating a lack of cross-resistance. Reference strain C. krusei (ATCC 6258, FLC-resistant) was consistently susceptible to AZA, although not to EIL. The fungicidal activity of 24-SMTI was particularly high against CNA isolates. Treatment with sub-inhibitory concentrations of AZA and EIL induced several ultrastructural alterations, including changes in the cell-wall shape and thickness, a pronounced disconnection between the cell wall and cytoplasm with an electron-lucent zone between them, mitochondrial swelling, and the presence of electron-dense vacuoles. Fluorescence microscopy analyses indicated an accumulation of lipid bodies and alterations in the cell cycle of the yeasts. The selectivity of 24-SMTI for fungal cells versus mammalian cells was assessed by the sulforhodamine B viability assay. CONCLUSION: Taken together, these results suggest that inhibition of 24-SMT may be a novel approach to control Candida spp. infections, including those caused by azole-resistant strains.
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spelling pubmed-26790252009-05-08 Growth inhibition and ultrastructural alterations induced by Δ(24(25))-sterol methyltransferase inhibitors in Candida spp. isolates, including non-albicans organisms Ishida, Kelly Rodrigues, Juliany Cola Fernandes Ribeiro, Marcos Dornelas Vila, Taíssa Vieira Machado de Souza, Wanderley Urbina, Julio A Nakamura, Celso Vataru Rozental, Sonia BMC Microbiol Research article BACKGROUND: Although Candida species are commensal microorganisms, they can cause many invasive fungal infections. In addition, antifungal resistance can contribute to failure of treatment. The purpose of this study was to evaluate the antifungal activity of inhibitors of Δ(24(25))-sterol methyltransferase (24-SMTI), 20-piperidin-2-yl-5α-pregnan-3β-20(R)-diol (AZA), and 24(R,S),25-epiminolanosterol (EIL), against clinical isolates of Candida spp., analysing the ultrastructural changes. RESULTS: AZA and EIL were found to be potent growth inhibitors of Candida spp. isolates. The median MIC(50 )was 0.5 μg.ml(-1 )for AZA and 2 μg.ml(-1 )for EIL, and the MIC(90 )was 2 μg.ml(-1 )for both compounds. All strains used in this study were susceptible to amphotericin B; however, some isolates were fluconazole- and itraconazole-resistant. Most of the azole-resistant isolates were Candida non-albicans (CNA) species, but several of them, such as C. guilliermondii, C. zeylanoides, and C. lipolytica, were susceptible to 24-SMTI, indicating a lack of cross-resistance. Reference strain C. krusei (ATCC 6258, FLC-resistant) was consistently susceptible to AZA, although not to EIL. The fungicidal activity of 24-SMTI was particularly high against CNA isolates. Treatment with sub-inhibitory concentrations of AZA and EIL induced several ultrastructural alterations, including changes in the cell-wall shape and thickness, a pronounced disconnection between the cell wall and cytoplasm with an electron-lucent zone between them, mitochondrial swelling, and the presence of electron-dense vacuoles. Fluorescence microscopy analyses indicated an accumulation of lipid bodies and alterations in the cell cycle of the yeasts. The selectivity of 24-SMTI for fungal cells versus mammalian cells was assessed by the sulforhodamine B viability assay. CONCLUSION: Taken together, these results suggest that inhibition of 24-SMT may be a novel approach to control Candida spp. infections, including those caused by azole-resistant strains. BioMed Central 2009-04-20 /pmc/articles/PMC2679025/ /pubmed/19379501 http://dx.doi.org/10.1186/1471-2180-9-74 Text en Copyright ©2009 Ishida et al; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research article
Ishida, Kelly
Rodrigues, Juliany Cola Fernandes
Ribeiro, Marcos Dornelas
Vila, Taíssa Vieira Machado
de Souza, Wanderley
Urbina, Julio A
Nakamura, Celso Vataru
Rozental, Sonia
Growth inhibition and ultrastructural alterations induced by Δ(24(25))-sterol methyltransferase inhibitors in Candida spp. isolates, including non-albicans organisms
title Growth inhibition and ultrastructural alterations induced by Δ(24(25))-sterol methyltransferase inhibitors in Candida spp. isolates, including non-albicans organisms
title_full Growth inhibition and ultrastructural alterations induced by Δ(24(25))-sterol methyltransferase inhibitors in Candida spp. isolates, including non-albicans organisms
title_fullStr Growth inhibition and ultrastructural alterations induced by Δ(24(25))-sterol methyltransferase inhibitors in Candida spp. isolates, including non-albicans organisms
title_full_unstemmed Growth inhibition and ultrastructural alterations induced by Δ(24(25))-sterol methyltransferase inhibitors in Candida spp. isolates, including non-albicans organisms
title_short Growth inhibition and ultrastructural alterations induced by Δ(24(25))-sterol methyltransferase inhibitors in Candida spp. isolates, including non-albicans organisms
title_sort growth inhibition and ultrastructural alterations induced by δ(24(25))-sterol methyltransferase inhibitors in candida spp. isolates, including non-albicans organisms
topic Research article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2679025/
https://www.ncbi.nlm.nih.gov/pubmed/19379501
http://dx.doi.org/10.1186/1471-2180-9-74
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