Affiliation:
1. Case Western Reserve University
2. Division of Infectious DiseasesDepartment of Medicine,
3. Department of Dermatology, University Hospitals of Cleveland, Cleveland, Ohio 44106
Abstract
ABSTRACT
Little is known about fungal biofilms, which may cause infection and antibiotic resistance. In this study, biofilm formation by different
Candida
species, particularly
Candida
albicans
and
C
.
parapsilosis
, was evaluated by using a clinically relevant model of
Candida
biofilm on medical devices.
Candida
biofilms were allowed to form on silicone elastomer and were quantified by tetrazolium (XTT) and dry weight (DW) assays. Formed biofilm was visualized by using fluorescence microscopy and confocal scanning laser microscopy with Calcofluor White (Sigma Chemical Co., St. Louis, Mo.), concanavalin A-Alexafluor 488 (Molecular Probes, Eugene, Oreg.), and FUN-1 (Molecular Probes) dyes. Although minimal variations in biofilm production among invasive
C
.
albicans
isolates were seen, significant differences between invasive and noninvasive isolates (
P
< 0.001) were noted.
C
.
albicans
isolates produced more biofilm than
C
.
parapsilosis
,
C
.
glabrata
, and
C
.
tropicalis
isolates, as determined by DW assays (
P
was <0.001 for all comparisons) and microscopy. Interestingly, noninvasive isolates demonstrated a higher level of XTT activity than invasive isolates. On microscopy,
C
.
albicans
biofilms had a morphology different from that of other species, consisting of a basal blastospore layer with a dense overlying matrix composed of exopolysaccharides and hyphae. In contrast,
C
.
parapsilosis
biofilms had less volume than
C
.
albicans
biofilms and were comprised exclusively of clumped blastospores. Unlike planktonically grown cells,
Candida
biofilms rapidly (within 6 h) developed fluconazole resistance (MIC, >128 μg/ml). Importantly, XTT and FUN-1 activity showed biofilm cells to be metabolically active. In conclusion, our data show that
C
.
albicans
produces quantitatively larger and qualitatively more complex biofilms than other species, in particular,
C
.
parapsilosis
.
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Immunology,Microbiology,Parasitology
Reference52 articles.
1. Anaissie, E. J., J. H. Rex, O. Uzon, and S. Vartivarian. 1998. Predictors of adverse outcome in cancer patients with candidemia. Am. J. Med.104:238-245.
2. Baillie, G. S., and L. J. Douglas. 1999. Candida biofilms and their susceptibility to antifungal agents. Methods Enzymol.310:644-656.
3. Baillie, G. S., and L. J. Douglas. 1999. Role of dimorphism in the development of Candidaalbicans biofilms. J. Med. Microbiol.48:671-679.
4. Baillie, G. S., and L. J. Douglas. 2000. Matrix polymers of Candida biofilms and their possible role in biofilm resistance to antifungal agents. J. Antimicrob. Chemother.46:397-403.
5. Banejee, S. N., G. T. Emori, D. H. Culver, R. P. Gaynes, W. R. Jarvis, T. Horan, J. R. Edwards, et al. 1991. Secular trends in nosocomial primary bloodstream infections in the United States, 1980-1989. Am. J. Med.91(Suppl. 3B):86-89.
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