CgCDR1, CgCDR2, and CgERG11 gene expression in Candida glabrata biofilms formed by bloodstream isolates

Abstract number: P702

Shin J.H., Kim S., Shin M., Suh S., Ryang D., Kee S.J., Jung S.I., Jang S.J., Lee H.S.

Objectives: A number of molecular mechanisms have been implicated in non-biofilm antifungal resistance in C. glabrata, but the relevance of these mechanisms to C. glabrata biofilm cells has rarely been examined. We determined whether the expression of azole-resistance genes is altered during the developmental phases of biofilm formation by C. glabrata

Methods: Four bloodstream isolates of C. glabrata from cases of central venous catheter-related fungaemia showing high in vitro biofilm formation were studied. A microtiter-plate-based colorimetric assay was used to test the fluconazole susceptibility of Candida biofilms at 80% inhibition using the 2,3-bis­[2-methyloxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide (XTT) reduction assay. The expression of CgCDR1, CgCDR2, and CgERG11 genes during the early (6 h), intermediate (15 h), and mature (48 h) phases of biofilm development, and corresponding planktonic cells, were examined using real-time PCR methods.

Results: The fluconazole minimum inhibitory concentrations (MIC) of C. glabrata biofilms formed at 6, 15, and 48 h were all >1,024 ug/ml. The biofilms at 15 h exhibited an approximately 3.3-fold upregulation of CgCDR1 compared with the corresponding planktonic cells, which was higher than the values for biofilms at 6 (1.5 fold) and 48 (0.8 fold) hours (P < 0.05). The CgCDR2 transcript levels for biofilms were also highest at 15 h (3.1-fold upregulation), but were minimal at 6 and 48 h (0.5 and 0.8 fold) (P < 0.05). By contrast, the CgERG11 transcript levels did not differ among the 6-, 15-, and 48-h biofilms.

Conclusion: Our study demonstrated a temporal increase in the expression of the CDR1 and CDR2 genes in C. glabrata biofilms formed by bloodstream isolates during the early biofilm development stage.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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