title: Transcriptional profiling of azole-resistant Candida parapsilosis strains.
abstract: Herein we describe the changes in the gene expression profile of Candida parapsilosis associated with the acquisition of experimentally induced resistance to azole antifungal drugs. Three resistant strains of C. parapsilosis were obtained following prolonged in vitro exposure of a susceptible clinical isolate to constant concentrations of fluconazole, voriconazole, or posaconazole. We found that after incubation with fluconazole or voriconazole, strains became resistant to both azoles but not to posaconazole, although susceptibility to this azole decreased, whereas the strain incubated with posaconazole displayed resistance to the three azoles. The resistant strains obtained after exposure to fluconazole and to voriconazole have increased expression of the transcription factor MRR1, the major facilitator transporter MDR1, and several reductases and oxidoreductases. Interestingly, and similarly to what has been described in C. albicans, upregulation of MRR1 and MDR1 is correlated with point mutations in MRR1 in the resistant strains. The resistant strain obtained after exposure to posaconazole shows upregulation of two transcription factors (UPC2 and NDT80) and increased expression of 13 genes involved in ergosterol biosynthesis. This is the first study addressing global molecular mechanisms underlying azole resistance in C. parapsilosis; the results suggest that similarly to C. albicans, tolerance to azoles involves the activation of efflux pumps and/or increased ergosterol synthesis.
authors.affiliation: Department of Microbiology, Faculty of Medicine, University of Porto, Porto, Portugal. atsilva@med.up.pt
authors.forename: A P
authors.initials: AP
authors.lastname: Silva
authors.forename: I M
authors.initials: IM
authors.lastname: Miranda
authors.forename: A
authors.initials: A
authors.lastname: Guida
authors.forename: J
authors.initials: J
authors.lastname: Synnott
authors.forename: R
authors.initials: R
authors.lastname: Rocha
authors.forename: R
authors.initials: R
authors.lastname: Silva
authors.forename: A
authors.initials: A
authors.lastname: Amorim
authors.forename: C
authors.initials: C
authors.lastname: Pina-Vaz
authors.forename: G
authors.initials: G
authors.lastname: Butler
authors.forename: A G
authors.initials: AG
authors.lastname: Rodrigues
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology*; D001393:Azoles / Q000494:pharmacology*; D002175:Candida / Q000187:drug effects* / Q000235:genetics*; D025141:Drug Resistance, Fungal / Q000235:genetics; D015725:Fluconazole / Q000494:pharmacology; D005656:Fungal Proteins / Q000235:genetics; D020869:Gene Expression Profiling; D008826:Microbial Sensitivity Tests; D011743:Pyrimidines / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014230:Triazoles / Q000494:pharmacology; D065819:Voriconazole
chemical_list: D000935:Antifungal Agents; D001393:Azoles; D005656:Fungal Proteins; D011743:Pyrimidines; D014230:Triazoles; C101425:posaconazole; D015725:Fluconazole; D065819:Voriconazole