Mating genotypes and susceptibility profiles of clinical isolates of Candida glabrata from Turkey

Abstract

The sexual cycle of Candida glabrata is not known; however, genomic evidence is indicative of recombination among subpopulations and the genome harbours genes necessary for undergoing mating and meiosis, which may increase fitness. The relationship between specific mating type-like (MTL) loci and antifungal susceptibility is not well understood in C. glabrata. We investigated different combinations of clinical C. glabrata isolate mating types and their antifungal susceptibility profiles. Allele profiles of the mating genes of 103 clinical C. glabrata isolates were identified, and their antifungal susceptibility to azoles, echinocandins and amphotericin B were compared. The majority (88.3%) of screened isolates harboured the a allele in the locus. The MTL1, MTL2 and MTL3 loci harboured a (88.3%), a (95.1%), and alpha (71.8%) alleles, respectively. The C. glabrata isolates were susceptible to echinocandins but displayed high minimal inhibitory concentrations (MICs) for azoles. The MIC ranges and MIC90 values of all isolates were 1.0 to >= 64 and 8.0 mu g mL(-1) for fluconazole, 0.06 to >= 16.0 and 0.5 mu g mL(-1) for voriconazole, 0.06 to >= 16.0 and 1.0 mu g mL(-1) for posaconazole, <= 0.015 to 0.06, and 0.03 mu g mL(-1) for caspofungin, <= 0.015 to 0.06 and 0.015 mu g mL(-1) for anidulafungin and 0.5-2 and 2.0 mu g mL(-1) for amphotericin B, respectively. The mating gene alleles of the clinical C. glabrata isolates were not associated with differences in the MICs of the tested antifungals, except for the MTL3 alpha-allele and echinocandins. The mating genotypes of the clinical C. glabrata isolates had no recognisable common effect on antifungal susceptibility.