Trailing end-point phenotype antibiotic-sensitive strains of Candida albicans produce different amounts of aspartyl peptidases

Trailing end-point phenotype antibiotic-sensitive strains of Candida albicans produce different amounts of aspartyl peptidases

Candida albicans is an opportunistic fungal pathogen that causes severe systemic infections in immunosuppressed individuals. C. albicans resistance to antifungal drugs is a severe problem in patients receiving prolonged therapy. Moreover, trailing yeast growth, which is defined as a resistant MIC after 48 h of incubation with triazole antifungal agents but a susceptible MIC after 24 h, has been noted in tests of antifungal susceptibility against some C. albicans isolates. In this context, we recently noticed this phenomenon in our routine susceptibility tests with fluconazole/itraconazole and C. albicans clinical isolates. In the present study, we investigated the production of cell-associated and secreted aspartyl peptidases (Saps) in six trailing clinical isolates of C. albicans, since this class of hydrolytic enzymes is a well-known virulence factor expressed by this fungal pathogen. Sap2, which is the best-studied member of the Sap family, was detected by flow cytometry on the cell surface of yeasts and as a 43-kDa polypeptide in the culture supernatant, as demonstrated by Western blotting assay using an anti-Sap1-3 polyclonal antibody. Released aspartyl peptidase activity was measured with BSA hydrolysis and inhibited by pepstatin A, showing distinct amounts of proteolytic activity ranging from 5.7 (strain 44B) to 133.2 (strain 11) arbitrary units. Taken together, our results showed that trailing clinical isolates of C. albicans produced different amounts of both cellular and secreted aspartyl-type peptidases, suggesting that this phenotypic feature did not generate a regular pattern regarding the expression of Sap.

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Main Authors: Braga-Silva,L.A., Mesquita,D.G.A., Ribeiro,M.D., Carvalho,S.M.F., Fracalanzza,S.E.L., Santos,A.L.S.
Format: Digital revista
Language:English
Published: Associação Brasileira de Divulgação Científica 2009
Online Access:http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2009000800013
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spelling oai:scielo:S0100-879X20090008000132009-07-31Trailing end-point phenotype antibiotic-sensitive strains of Candida albicans produce different amounts of aspartyl peptidasesBraga-Silva,L.A.Mesquita,D.G.A.Ribeiro,M.D.Carvalho,S.M.F.Fracalanzza,S.E.L.Santos,A.L.S. Candida albicans Trailing growth Secreted aspartyl peptidases Sap2 Candida albicans is an opportunistic fungal pathogen that causes severe systemic infections in immunosuppressed individuals. C. albicans resistance to antifungal drugs is a severe problem in patients receiving prolonged therapy. Moreover, trailing yeast growth, which is defined as a resistant MIC after 48 h of incubation with triazole antifungal agents but a susceptible MIC after 24 h, has been noted in tests of antifungal susceptibility against some C. albicans isolates. In this context, we recently noticed this phenomenon in our routine susceptibility tests with fluconazole/itraconazole and C. albicans clinical isolates. In the present study, we investigated the production of cell-associated and secreted aspartyl peptidases (Saps) in six trailing clinical isolates of C. albicans, since this class of hydrolytic enzymes is a well-known virulence factor expressed by this fungal pathogen. Sap2, which is the best-studied member of the Sap family, was detected by flow cytometry on the cell surface of yeasts and as a 43-kDa polypeptide in the culture supernatant, as demonstrated by Western blotting assay using an anti-Sap1-3 polyclonal antibody. Released aspartyl peptidase activity was measured with BSA hydrolysis and inhibited by pepstatin A, showing distinct amounts of proteolytic activity ranging from 5.7 (strain 44B) to 133.2 (strain 11) arbitrary units. Taken together, our results showed that trailing clinical isolates of C. albicans produced different amounts of both cellular and secreted aspartyl-type peptidases, suggesting that this phenotypic feature did not generate a regular pattern regarding the expression of Sap.info:eu-repo/semantics/openAccessAssociação Brasileira de Divulgação CientíficaBrazilian Journal of Medical and Biological Research v.42 n.8 20092009-08-01info:eu-repo/semantics/articletext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2009000800013en10.1590/S0100-879X2009000800013
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country Brasil
countrycode BR
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databasecode rev-scielo-br
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region America del Sur
libraryname SciELO
language English
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author Braga-Silva,L.A.
Mesquita,D.G.A.
Ribeiro,M.D.
Carvalho,S.M.F.
Fracalanzza,S.E.L.
Santos,A.L.S.
spellingShingle Braga-Silva,L.A.
Mesquita,D.G.A.
Ribeiro,M.D.
Carvalho,S.M.F.
Fracalanzza,S.E.L.
Santos,A.L.S.
Trailing end-point phenotype antibiotic-sensitive strains of Candida albicans produce different amounts of aspartyl peptidases
author_facet Braga-Silva,L.A.
Mesquita,D.G.A.
Ribeiro,M.D.
Carvalho,S.M.F.
Fracalanzza,S.E.L.
Santos,A.L.S.
author_sort Braga-Silva,L.A.
title Trailing end-point phenotype antibiotic-sensitive strains of Candida albicans produce different amounts of aspartyl peptidases
title_short Trailing end-point phenotype antibiotic-sensitive strains of Candida albicans produce different amounts of aspartyl peptidases
title_full Trailing end-point phenotype antibiotic-sensitive strains of Candida albicans produce different amounts of aspartyl peptidases
title_fullStr Trailing end-point phenotype antibiotic-sensitive strains of Candida albicans produce different amounts of aspartyl peptidases
title_full_unstemmed Trailing end-point phenotype antibiotic-sensitive strains of Candida albicans produce different amounts of aspartyl peptidases
title_sort trailing end-point phenotype antibiotic-sensitive strains of candida albicans produce different amounts of aspartyl peptidases
description Candida albicans is an opportunistic fungal pathogen that causes severe systemic infections in immunosuppressed individuals. C. albicans resistance to antifungal drugs is a severe problem in patients receiving prolonged therapy. Moreover, trailing yeast growth, which is defined as a resistant MIC after 48 h of incubation with triazole antifungal agents but a susceptible MIC after 24 h, has been noted in tests of antifungal susceptibility against some C. albicans isolates. In this context, we recently noticed this phenomenon in our routine susceptibility tests with fluconazole/itraconazole and C. albicans clinical isolates. In the present study, we investigated the production of cell-associated and secreted aspartyl peptidases (Saps) in six trailing clinical isolates of C. albicans, since this class of hydrolytic enzymes is a well-known virulence factor expressed by this fungal pathogen. Sap2, which is the best-studied member of the Sap family, was detected by flow cytometry on the cell surface of yeasts and as a 43-kDa polypeptide in the culture supernatant, as demonstrated by Western blotting assay using an anti-Sap1-3 polyclonal antibody. Released aspartyl peptidase activity was measured with BSA hydrolysis and inhibited by pepstatin A, showing distinct amounts of proteolytic activity ranging from 5.7 (strain 44B) to 133.2 (strain 11) arbitrary units. Taken together, our results showed that trailing clinical isolates of C. albicans produced different amounts of both cellular and secreted aspartyl-type peptidases, suggesting that this phenotypic feature did not generate a regular pattern regarding the expression of Sap.
publisher Associação Brasileira de Divulgação Científica
publishDate 2009
url http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2009000800013
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