Previous Article | Next Article ![]()
Applied and Environmental Microbiology, August 2007, p. 4940-4949, Vol. 73, No. 15
0099-2240/07/$08.00+0 doi:10.1128/AEM.02711-06
Copyright © 2007, American Society for Microbiology. All Rights Reserved.
,
Department of Biological Sciences, University of Calgary, 2500 University Drive N.W., Calgary, Canada T2N 1N4,1 Biofilm Research Group, University of Calgary, 2500 University Drive N.W., Calgary, Canada T2N 1N4,2 Electrical and Computer Engineering, Schulich School of Engineering, University of Calgary, 2500 University Drive N.W., Calgary, Canada T2N 1N4,3 Mechanical and Manufacturing Engineering, Schulich School of Engineering, University of Calgary, 2500 University Drive N.W., Calgary, Canada T2N 1N44
Received 20 November 2006/ Accepted 26 May 2007
Candida albicans and Candida tropicalis are polymorphic fungi that develop antimicrobial-resistant biofilm communities that are characterized by multiple cell morphotypes. This study investigated cell type interconversion and drug and metal resistance as well as community organization in biofilms of these microorganisms that were exposed to metal ions. To study this, Candida biofilms were grown either in microtiter plates containing gradient arrays of metal ions or in the Calgary Biofilm Device for high-throughput susceptibility testing. Biofilm formation and antifungal resistance were evaluated by viable cell counts, tetrazolium salt reduction, light microscopy, and confocal laser scanning microscopy in conjunction with three-dimensional visualization. We discovered that subinhibitory concentrations of certain metal ions (CrO42–, Co2+, Cu2+, Ag+, Zn2+, Cd2+, Hg2+, Pb2+, AsO2–, and SeO32–) caused changes in biofilm structure by blocking or eliciting the transition between yeast and hyphal cell types. Four distinct biofilm community structure types were discerned from these data, which were designated "domed," "layer cake," "flat," and "mycelial." This study suggests that Candida biofilm populations may respond to metal ions to form cell-cell and solid-surface-attached assemblages with distinct patterns of cellular differentiation.
Published ahead of print on 8 June 2007.
Supplemental material for this article may be found at http://aem.asm.org/.
This article has been cited by other articles:
Copyright © 2010 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»