High Virulence and Antifungal Resistance in Clinical Strains ofCandida albicans

Abstract

Antifungal resistance and virulence properties ofCandida albicansare a growing health problem worldwide. To study the expression of virulence and azole resistance genes in 39 clinical strains ofC. albicans, we used a model of infection of human vaginal epithelial cells withC. albicansstrains isolated from Mexican women with vulvovaginal candidiasis (VVC). The strains were identified by PCR amplification of the ITS1 and ITS2 regions of rRNA. The detection and expression of virulence genes and azole resistance genesMDR1andCDR1were performed using PCR and RT-PCR, respectively. All strains were sensitive to nystatin and 38 (97.4%) and 37 (94.9%) were resistant to ketoconazole and fluconazole, respectively.ALS1,SAP4–SAP6,LIP1,LIP2,LIP4,LIP6,LIP7,LIP9,LIP10, andPLB1-PLB2were present in all strains;SAP1was identified in 37 (94.8%) isolates,HWP1in 35 (89.7%),ALS3in 14 (35.8%), andCDR1in 26 (66.6%). In nearly all of the strains,ALS1,HWP1,SAP4–SAP6,LIP1–LIP10,PLB1, andPLB2were expressed, whereasCDR1was expressed in 20 (51.3%) andALS3in 14 (35.8%). In our in vitro model of infection withC. albicans, the clinical strains showed different expression profiles of virulence genes in association with the azole resistance geneCDR1. The results indicate that the strains that infect Mexican patients suffering from VVC are highly virulent and virtually all are insensitive to azoles.