[Biofilm production and antifungal susceptibility patterns of Candida species].
In this study, biofilm production and antifungal susceptibility of various Candida species were examined and compared. A total number of 156 Candida species (94 C. albicans, 21 C. tropicalis, 18 C. glabrata, 12 C. parapsilosis, 9 C. krusei, 1 C. guilliermondii and 1 C. kefyr) isolated from different clinical specimens were included in the study. The biofilm production of the strains was searched by modified tube adherence and microplate methods. Their antifungal susceptibilities against fluconazole and amphotericin B were determined by microdilution method, according to NCCLS M27-A2 standards. Forty three (27.6%) and 26 (16.7%) of the strains were found to be slime producing by tube adherence and microplate methods, respectively. The agreement between the two methods were detected as 65 percent. The rate of biofilm formation by different species ranged between 17% and 55% by tube adherence test and 0 and 48% by microplate method. No significant difference was found between the biofilm production of C. albicans and non-albicans species by tube adherence test (p=0.29). However; a statistically important difference was found when microplate method was considered (p=0.04). MIC50 and MIC90 values for fluconazole ranged between 4-64 microg/ml and 32-->64 microg/ml for different Candida species while these values changed between 0.25-1 microg/ml and 0.5-2 microg/ml for amphotericin B, respectively. Forty-five (28.8%) and 23 (14.7%) of the isolates were found to be dose dependent susceptible and resistant to fluconazole, respectively. Eleven (6.7%) of the strains had MIC values >1 microg/ml for amphotericin B. When the relation between the biofilm production and the susceptibility categories of the strains for amphotericin B were searched, no statistical differences were found by any of the two methods (p=0.12 and p=0.50). A statistically important difference (p=0.03) was determined by tube adherence test and no important difference (p=0.11) was detected by microplate method when fluconazole susceptibility categories were considered. As a conclusion, it has been determined that biofilm production which is a potential virulence factor for Candida species seems to be in agreement with the antifungal susceptibility categories of the strains especially for amphotericin B when the planktonic cells were used for the susceptibility testing.
Yücesoy
Mine
M
Dokuz Eylül Universitesi Tip Fakültesi, Mikrobiyoloji ve Klinik Mikrobiyoloji Anabilim Dali, Izmir.
Karaman
Meral
M
D000666:Amphotericin B / Q000494:pharmacology*; D000935:Antifungal Agents / Q000494:pharmacology*; D018441:Biofilms / Q000254:growth & development*; D002175:Candida / Q000187:drug effects* / Q000472:pathogenicity; D004305:Dose-Response Relationship, Drug; D025141:Drug Resistance, Fungal; D015725:Fluconazole / Q000494:pharmacology*; D006801:Humans; D008826:Microbial Sensitivity Tests; D015203:Reproducibility of Results; D037521:Virulence Factors
D000935:Antifungal Agents; D037521:Virulence Factors; D000666:Amphotericin B; D015725:Fluconazole