Detection of ERG11 gene mutation in coding and non-coding region of clinical Candida glabrata (Nakaseomyces glabratu s) isolates from Pakistan

Abstract Azoles inhibit the cytochrome P450 dependent enzyme lanosterol-14α-demethylase (CYP51) that is encoded by ERG11gene. Azole resistance in Candida species arises through different mechanisms, like mutation in the ERG11gene, ERG11 overexpression, CDR1,2 overexpression, and biofilm formation. We sequenced ERG11 gene to determine mutations in coding and non-coding region of ERG11 in clinical isolates of Candida glabrata (Nakaseomyces glabratus) from Pakistan. Eight C. glabrata (N. glabratus) strains from our fungal strain bank (five fluconazole resistant and three susceptible dose-dependent) were revived and used. The ERG11 gene was amplified by PCR, sequenced using Sanger methodology, and analyzed using bioinformatic tools. We identified a change in nucleotide at c. -66 T/G upstream of start codon ATG of ERG11gene in fluconazole resistant C. glabrata (N. glabratus). Two novel synonymous mutations at position T300C and T834C, and previously reported synonymous mutations T768C, A1023G, T1557A and A1581G were also observed. This is the first study evaluating ERG11 mutations in C. glabrata (N. glabratus) from Pakistan. Clinical significance of such uncommon ERG11 gene mutations as T496G should be explored further through correlation with treatment outcome data.