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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Biofilm production and evaluation of antifungal susceptibility amongst clinical Candida spp. isolates, including strains of the Candida parapsilosis complex

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Author(s):
Melo, Analy S. ; Bizerra, Fernando C. ; Freymueller, Edna [1] ; Arthington-Skaggs, Beth A. [2] ; Colombo, Arnaldo L. [3]
Total Authors: 5
Affiliation:
[1] Univ Fed Sao Paulo, Ctr Electron Microscopy, BR-04023062 Sao Paulo - Brazil
[2] Ctr Dis Control & Prevent, Mycot Dis Branch, Atlanta, GA - USA
[3] Univ Fed Sao Paulo, Disciplina Infectol, Lab Especial Micol, Div Infect Dis, BR-04023062 Sao Paulo - Brazil
Total Affiliations: 3
Document type: Journal article
Source: Medical Mycology; v. 49, n. 3, p. 253-262, APR 2011.
Web of Science Citations: 83
Abstract

Candida cells can form biofilms that frequently are sources of infections and are less susceptible to antifungal drugs. Some authors have reported that Candida orthopsilosis and Candida metapsilosis isolates are not able to produce biofilms in vitro and there are no studies available on biofilm susceptibility for these species to antifungals. The aims of this study were to (i) quantify Candida spp. biofilms in vitro, and (ii) test the in vitro susceptibilities of Candida spp. biofilms to fluconazole (FLC) and amphotericin B (AMB). Isolates studied included four Candida albicans, six C. tropicalis, seven C. parapsilosis, eight C. orthopsilosis, and five C. metapsilosis. We compared two different methods to evaluate biofilm production, i. e., crystal violet (CV) staining and XTT-reduction assays (XTT). Scanning electron microscopy (SEM) was used to observe high, medium and low biofilm producing isolates screened by these two methods. To determine the minimum biofilm eradication concentration (MBEC) for FLC and AMB, XTT-reduction assay was used to measure cell metabolic activity. Biofilm quantification by CV and XTT showed that C. tropicalis isolates were the highest biofilm producer, followed by C. albicans, C. parapsilosis, C. orthopsilosis and C. metapsilosis. Examination of SEM images revealed that the extent of biofilms formed by high, medium, and low producers was highly correlated to the results generated by CV assay. Biofilm of all the isolates evaluated were resistant to FLC (MBEC(80) >= 256 ug/ml) but, in general, susceptible to AMB, except for six C. parapsilosis strains (MBEC (80) >= 8 ug/ml). (AU)