Azole Resistance and ERG11 464 Polymorphism in Oral Candida albicans Clinical Strains Isolated in Sardinia

The in vitro activity of three different azoles (fluconazole, FLC, voriconazole, VRC and ketoconazole, KTC) was determined and correlated with the single nucleotide polymorphisms (SNPs) in a “hot spot” region of the ERG11 gene in a collection of 52 arbitrarily selected C. albicans strains isolated from Sardinian subjects with oropharyngeal candidiasis. Among the strains evaluated, 23.1% were resistant, 9.6% Sensible Dose Dependent (SDD) and 67.3% susceptible to FLC. Among the FLC resistant strains, 83.3% were also cross-resistant to VRC (10/12) and 66.6% to KTC (8/12). The homozygous point mutation G464S was only detected in four out of five SDD to fluconazole strains. These data showed that the resistance of Candida albicans to azoles and the mutation at codon 464 of ERG11 are not associated. In addition the results also indicate a high prevalence of azole-resistant and cross resistant strains among these patients.