Antifungal resistance of Candida glabrata vaginal isolates and development of a quantitative reverse transcription-PCR-based azole susceptibility assay

Abstract

A multiplex quantitative reverse transcription-PCR assay was developed to detect azole resistance in Candida glabrata, an important opportunistic pathogen that develops resistance rapidly. Resistance was defined as a >or=3-fold increase in CDR1 expression by this assay, which proved to be 100% sensitive and 95% specific in comparison to the gold standard broth microdilution assay.

FIG. 1.

Gene expression profiles within the susceptibility groups. Clinical isolates were tested for fluconazole susceptibility by MBD (9), and the results were compared to qRT-PCR expression levels of CDR1 (A), PDH1 (B), and PDR1 (C). The heavy solid horizontal bars represent the median values. The horizontal dotted line represents a twofold increase in expression level above that for the susceptible panel. The vertical dotted lines distinguish the three susceptibility groups as determined by CLSI breakpoints for Candida species.