The role of Cap1, Mrr1 and MDR1 genes in azole cross-resistant candida albicans clinically isolated from VVC patients

Abstract

Objective To investigate the role of zinc cluster transcription factors Cap1 and Mrr1 mutation/high expression and the mRNA level of efflux pump MDR1 in Candida albicans cross- resistant to azole antifungal agents such as fluconazole (FCA) , itraconazole (ITR) , and voriconazole (VRC). Methods Vaginal swabs from patients with suspected vulvovaginal candidiasis (VVC) in the Department of Dermatology, Second Hospital of Shanxi Medical University, were collected for direct microscopy, culture, isolation, identification and in vitro drug sensitivity test. A total of 68 Candida albicans resistant and susceptible strains were obtained. Cap1 and Mrr1 in the 68 clinically isolated strains of Candida albicans were PCR - amplified and bidirectionally sequenced. Blast software was used to compare the sequencing results with published sequences in GenBank for identification of gene mutations. Real- time fluorescent quantitative PCR was used to detect mRNA expression of zinc cluster transcription factors Cap1 and Mrr1 and efflux pump gene MDR1. Results By Cap1 sequencing, P311S missense mutation was found in one strain cross-resistant to ITR and VRC. By Mrr1 sequencing, five missense mutations (T917M, T923I, E1020Q, F1032L, and S1037L) were found in one strain cross-resistant to FCA, ITR and VRC. The expression level of Cap1/Mrr1/MDR1 mRNA was higher in FCA, ITR and VRC cross- resistant strains than in sensitive strains. In CA, ITR and VRC cross-resistant strains, there was no correlation in expression levels between Cap1 and MDR1 (r=0.173, P=0.571) , between Mrr1 and MDR1 (r=-0.091 , P=0.766) , or between Cap1 and Mrr1 (r=0.025, P=0.936) (all P>0.05) . Conclusion This study showed that mutations in Cap1 and Mrr1 may be related to azoles cross-resistance. Key words: Candidiasis, vulvovaginal; Candida albicans; Transcription factor; Efflux pump; Gene mutation