Author(s):
Silva, Sónia Carina 
; Henriques, Mariana ; Martins, António ; Oliveira, Rosário ; Williams, David ; Azeredo, Joana
Date: 2009
Persistent ID: http://hdl.handle.net/1822/10514
Origin: RepositóriUM - Universidade do Minho
Subject(s): Biofilm; non-Candida albicans Candida species
Description
Most cases of candidiasis have been attributed to C. albicans, but recently, non-
Candida albicans Candida (NCAC) species have been identified as common
pathogens. The ability of Candida species to form biofilms has important clinical
repercussions due to their increased resistance to antifungal therapy and the ability
of yeast cells within the biofilms to withstand host immune defenses. Given this
clinical importance of the biofilm growth form, the aim of this study was
to characterize biofilms produced by three NCAC species, namely C. parapsilosis,
C. tropicalis and C. glabrata. The biofilm forming ability of clinical isolates of
C. parapsilosis, C. tropicalis and C. glabrata recovered from different sources, was
evaluated by crystal violet staining. The structure and morphological characteristics
of the biofilms were also assessed by scanning electron microscopy and the
biofilm matrix composition analyzed for protein and carbohydrate content. All
NCAC species were able to form biofilms although these were less extensive for
C. glabrata compared with C. parapsilosis and C. tropicalis. It was evident that C.
parapsilosis biofilm production was highly strain dependent, a feature not evident
with C. glabrata and C. tropicalis. Scanning electron microscopy revealed structural
differences for biofilms with respect to cell morphology and spatial arrangement.
Candida parapsilosis biofilm matrices had large amounts of carbohydrate with less
protein. Conversely, matrices extracted from C. tropicalis biofilms had low
amounts of carbohydrate and protein. Interestingly, C. glabrata biofilm matrix
was high in both protein and carbohydrate content. The present work demonstrates
that biofilm forming ability, structure and matrix composition are highly
species dependent with additional strain variability occurring with C. parapsilosis.
