Fluconazole resistance in Candida glabrata is associated with increased bud formation and metallothionein production

Abstract

Virulence associated with fluconazole (FL) resistance in Candida glabrata is a global problem and has not been well characterized at the proteome level. In this study, a stable FL-resistant (MIC .256 mg ml "1 ) strain of C. glabrata was generated on agar containing FL. Eight phenotypic mutants were characterized by contour-clamped homogeneous electrophoretic field analysis and two-dimensional PAGE. The secondary derivatives of C. glabrata yielded four distinct genotypes with varying chromosomal profiles. Proteomic analysis performed by tandem mass spectrometry for two of the mutants, CG L2 and CG S3 , demonstrated a total of 25 differentially regulated proteins of which 13 were upregulated and 12 were downregulated or were similar compared with the parental isolate. The mRNA transcript levels of significantly (P,0.001) upregulated genes were determined by quantitative RT-PCR analysis, and their physiological relevance in terms of phenotypic expression of virulence attributes was verified by conventional laboratory methodologies. The data showed that the FL resistance (MIC .256 mg ml "1 ) of CG S3 was associated with significantly upregulated (P,0.001) mRNA transcript levels of several genes -ERG11, CDR1, CDR2, MFS, MTI, TPR, VPS and EFT2 -in addition to a number of other potentially virulent genes expressed differentially at a lower level. The results demonstrated accentuated phenotypic expression of bud formation of yeast and metallothionein production associated with FL resistance in C. glabrata, which may help the fungus to colonize the host.

Antifungal, Antitumoral and Antioxidant Potential of the Danube Delta Nymphaea alba Extracts

“…The antifungal activity (MIC) was evaluated in vitro against 4 fungal strains C. glabrata CBS 138, C. albicans SC 5134, C. parapsilosis ATCC22019 and C. tropicalis ATCC750 using N. alba extracts with concentrations between 0.23 and 2000 µg/mL, and fluconazole (FLC) as control with concentrations between 0.23 and 250 µg/mL ( Figure 5). The N. alba leaf and root extracts were found to be active against C. glabrata, with MIC values of 1.717 and 1.935 µg/mL for leaf and root extracts, and 0.7639 for FLC, respectively [37]. The obtained results showed that the action of the extracts was specific for C. glabrata, having no action on the other Candida strains tested.…”

Effects of fluconazole onCandida glabratabiofilms and its relationship with ABC transporter gene expression

“…Resistance to FLU by C. glabrata cells has been attributed to the transcriptional induction and upregulation of genes encoding ATP-binding cassette (ABC) transporters (CDR1, CDR2 and SNQ2) (Tscherner et al 2011;Samaranayake et al 2013). On the other hand, a mutation in the gene that encodes a regulator of multidrug transporter genes, PDR1, was associated with its upregulation.…”

“…It can be speculated that FLU might be triggering the production and secretion of polysaccharides and proteins that make the biofilm structure more cohesive and less hydrated, contributing to a lower uptake of crystal violet, and thus indicating a lower biomass. On the other hand, FLU might be stimulating the expression of genes involved in the efflux pumps, a well-known mechanism of FLU resistance (Vermitsky & Edlind 2004;Tscherner et al 2011;Samaranayake et al 2013) that contributes to increasing the flow rate inside the biofilm leading to a Biofouling 455 biofilm structure in cluster form. To test this hypothesis the expression of ABC transporter genes (SNQ2 and CDR1) as well as the zinc finger transcription factor (PDR1) that regulates drug efflux pumps was measured in planktonic and in biofilm cultures after being treated with FLU.…”

A case report of invasive candidiasis and fungal osteomyelitis mimicking oropharyngeal carcinoma recurrence in an immunocompetent patient following transoral robotic surgery

“…The commonest treatment for candida infections is oral fluconazole as it can effectively treat Candida Albicans . However, non-albicans species of candida, such as Candida Glabrata are reported to be more resistant to fluconazole [15] and require either a higher dose of fluconazole [16] or other forms of antifungal treatment. It is known that non-Albicans species of Candida have increased resistance to oral fluconazole [17], [18] and may also produce a biofilm on the mucous membranes of the oropharynx [16].…”