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Conference Paper: Fluconazole induces phenotypic, genotypic and proteomic changes in C. glabrata

TitleFluconazole induces phenotypic, genotypic and proteomic changes in C. glabrata
Authors
Issue Date2010
PublisherSage Publications, Inc.. The Journal's web site is located at http://www.sagepub.com/journalsProdDesc.nav?prodId=Journal201925
Citation
The 88th General Session & Exhibition of the International Association of Dental Research (IADR), Barcelona, Spain, 14-17 July 2010. In Journal of Dental Research, 2010, v. 89, Special Issue B, p. 1785 How to Cite?
AbstractCandida glabrata is a major pathogen in compromised patient populations due to its increased resistance to fluconazole (FL). Although the increase in fluconazole resistance is associated with changes in its genotype no parallel phenotypic or proteomic changes have been studied. OBJECTIVES: To observe specific phenotypic, chromosomal and proteomic alterations in a C. glabrata strain sequentially exposed to fluconazole. METHODS: C. glabrata was subjected to serial exposure of minimum concentrations (×MICs) of fluconazole in RPMI medium for a period of 55 days. Phenotypic changes (i.e., resistance to azole drugs, adhesion to BECs, phospholipase, haemolysin production, phenotypic switching) were evaluated at different time points using standard assays. The development of molecular/ proteomic changes in C. glabrata were analyzed by contour-clamped-homogeneous electrophoretic field (CHEF) electrophoresis, RT-PCR, 2-DE gel based methodology and mass spectrometric peptide finger print analysis of SDS-PAGE yeast separated protein fractions. RESULTS: C. glabrata demonstrated increased FL resistance (8->256µg/ml) accompanied with extensive cross-resistance to ketoconazole (0.38-3.0µg), itraconazole (8->32µg) and voriconazole (0.125-1.5µg). Variable colony morphology (size), a decrease in viable yeast counts, and inconsistent phenotypic switching on CuSO4 agar was observed. Further, seven randomly selected morphologically dissimilar yeast colonies also demonstrated pronounced differences in their chromosomal profiles compared with the control isolate. Stable changes in the chromosomal profiles of two yeast colonies were associated with significantly (p<0.05) higher transcript levels of the haemolysin gene relative to the control. Proteome analysis of one stable colony resulted in a total of 98 spots with 25 upregulated and 24 downregulated proteins. CONCLUSION: These findings show that sequential fluconazole exposure initiates the chance evolution of a new colonizing population with specific virulence traits. (Supported by the Research Grants Council, University of Hong Kong, SAR. We are grateful for the Pfizer Laboratories for supplying Fluconazole for this study).
DescriptionPoster presentations
Persistent Identifierhttp://hdl.handle.net/10722/133687
ISSN
2015 Impact Factor: 4.602
2015 SCImago Journal Rankings: 1.714

 

DC FieldValueLanguage
dc.contributor.authorSamaranayake, YHen_US
dc.contributor.authorCheung, BPKen_US
dc.contributor.authorYau, JYYen_US
dc.contributor.authorYeung, KWSen_US
dc.contributor.authorSamaranayake, LPen_US
dc.date.accessioned2011-05-24T02:15:04Z-
dc.date.available2011-05-24T02:15:04Z-
dc.date.issued2010en_US
dc.identifier.citationThe 88th General Session & Exhibition of the International Association of Dental Research (IADR), Barcelona, Spain, 14-17 July 2010. In Journal of Dental Research, 2010, v. 89, Special Issue B, p. 1785en_US
dc.identifier.issn0022-0345-
dc.identifier.urihttp://hdl.handle.net/10722/133687-
dc.descriptionPoster presentations-
dc.description.abstractCandida glabrata is a major pathogen in compromised patient populations due to its increased resistance to fluconazole (FL). Although the increase in fluconazole resistance is associated with changes in its genotype no parallel phenotypic or proteomic changes have been studied. OBJECTIVES: To observe specific phenotypic, chromosomal and proteomic alterations in a C. glabrata strain sequentially exposed to fluconazole. METHODS: C. glabrata was subjected to serial exposure of minimum concentrations (×MICs) of fluconazole in RPMI medium for a period of 55 days. Phenotypic changes (i.e., resistance to azole drugs, adhesion to BECs, phospholipase, haemolysin production, phenotypic switching) were evaluated at different time points using standard assays. The development of molecular/ proteomic changes in C. glabrata were analyzed by contour-clamped-homogeneous electrophoretic field (CHEF) electrophoresis, RT-PCR, 2-DE gel based methodology and mass spectrometric peptide finger print analysis of SDS-PAGE yeast separated protein fractions. RESULTS: C. glabrata demonstrated increased FL resistance (8->256µg/ml) accompanied with extensive cross-resistance to ketoconazole (0.38-3.0µg), itraconazole (8->32µg) and voriconazole (0.125-1.5µg). Variable colony morphology (size), a decrease in viable yeast counts, and inconsistent phenotypic switching on CuSO4 agar was observed. Further, seven randomly selected morphologically dissimilar yeast colonies also demonstrated pronounced differences in their chromosomal profiles compared with the control isolate. Stable changes in the chromosomal profiles of two yeast colonies were associated with significantly (p<0.05) higher transcript levels of the haemolysin gene relative to the control. Proteome analysis of one stable colony resulted in a total of 98 spots with 25 upregulated and 24 downregulated proteins. CONCLUSION: These findings show that sequential fluconazole exposure initiates the chance evolution of a new colonizing population with specific virulence traits. (Supported by the Research Grants Council, University of Hong Kong, SAR. We are grateful for the Pfizer Laboratories for supplying Fluconazole for this study).-
dc.languageengen_US
dc.publisherSage Publications, Inc.. The Journal's web site is located at http://www.sagepub.com/journalsProdDesc.nav?prodId=Journal201925-
dc.relation.ispartofJournal of Dental Researchen_US
dc.rightsJournal of Dental Research. Copyright © Sage Publications, Inc..-
dc.titleFluconazole induces phenotypic, genotypic and proteomic changes in C. glabrataen_US
dc.typeConference_Paperen_US
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0022-0345&volume=89&issue=Special Issue B&spage=1785&epage=&date=2010&atitle=Fluconazole+induces+phenotypic,+genotypic+and+proteomic+changes+in+C.+glabrata-
dc.identifier.emailSamaranayake, YH: hema@hkucc.hku.hken_US
dc.identifier.emailCheung, BPK: bpkcheun@hkucc.hku.hken_US
dc.identifier.emailYau, JYY: yaujyy@hkucc.hku.hken_US
dc.identifier.emailYeung, KWS: skwyeung@HKUCC.hku.hken_US
dc.identifier.emailSamaranayake, LP: lakshman@hku.hken_US
dc.identifier.authoritySamaranayake, YH=rp00025en_US
dc.identifier.authoritySamaranayake, LP=rp00023en_US
dc.identifier.hkuros185219en_US
dc.identifier.volume89en_US
dc.identifier.issueSpecial Issue Ben_US
dc.identifier.spage1785en_US
dc.identifier.epage1785en_US
dc.description.otherThe 88th General Session & Exhibition of the International Association of Dental Research (IADR), Barcelona, Spain, 14-17 July 2010. In Journal of Dental Research, 2010, v. 89, Special Issue B, p. 1785-

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