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Aim: This work studied the impact of the quorum-sensing molecule, farnesol (FAR), on fluconazole (FLC)-resistant Candida albicans isolate CY 1123 compared with the susceptible standard strain C. albicans SC5314. The genes encoding efflux pumps belonging to the ATP-binding cassette (ABC) and major facilitator superfamilies, together with overexpression or point mutation of the ERG11 gene, are the main resistance mechanisms to azole antifungal drugs. Results: The upregulation of genes coding for CDR1, CDR2, and MDR1 were confirmed by qPCR with respect to the housekeeping gene ACT1 in the resistant strain. The contribution of the ERG11 gene was also observed. Markedly, increased pump activity (Cdr1 and/or Cdr2) in the CY 1123 strain was confirmed using diS-C3(3) assay. However, the addition of FAR to the yeasts diminished the difference in staining levels between the SC5314 and CY 1123 strains, demonstrating the concentration-dependent character that could be caused by an effective modulation of Cdr pumps. FAR (60 and 100 μM) was also able to decrease the minimal inhibitory concentrations (MIC50), denoting the inhibition of planktonic cells by 50%, from 8 to 4 μg/mL of FLC when the resistant strain CY 1123 was not cultivated with FLC. However, when it was exposed to 64 μg/mL of FLC, the MIC50 shifted from 64 to 8 μg/mL. Conclusion: Besides the many other effects of FAR on eukaryotic and prokaryotic cells, it also affects ABC efflux transporters, resulting in changes in resistance to azoles in C. albicans isolates. However, this effect is dependent on FAR concentrations.

Článek

The impact of farnesol in combination with fluconazole on Candida albicans biofilm: regulation of ERG20, ERG9, and ERG11 genes

Folia microbiologica. 2018 ; 63 (3) : 363-371. [pub] 20171212

Folia microbiol. (Prague)
ISSN 1874-9356
Medvik
Zdroj

Farnesol (FAR) has already demonstrated an inhibitory effect on Candida albicans biofilm. The aim of this work was to determine the effectiveness of externally added FAR in combination with fluconazole (FLC) on Candida albicans biofilm and on regulation of the ergosterol genes ERG20, ERG9, and ERG11. The effectiveness of compounds was determined by MTT assay and evaluated by the minimal inhibitory concentrations reducing a sessile biofilm to 50% activity (0.5 μg/mL and 200 μmol/L for FLC and FAR, respectively). These concentrations as well as 30 and 100 μmol/L FAR were selected for a study of the effectiveness of the FAR/FLC combination. The reduction in biofilm robustness mainly caused by the presence of 200 μmol/L FAR-alone or in combination with FLC-was accompanied by a significant inhibition of the yeast-to-hyphae transition that was observed by light microscopy and CLSM. Results from qRT-PCR indicated that while 30 μmol/L FAR only slightly regulated the expression of all 3 genes in the 48-h biofilm, the presence of 200 μmol/L FAR downregulated all the tested genes. However, the addition of 0.5 μg/mL of FLC to the samples with 200 μmol/L FAR restored the downregulation of the ERG20 and ERG11 genes to the control level. Moreover, the gene ERG9 was slightly upregulated. In summary, FAR acted via multiple effects on the C. albicans biofilm, but only a higher concentration of FAR proved to be effective.

Článek

Zápis zo schôdze výboru ČSSM zo dňa 27.9.2018, Bratislava

Bulletin Československé společnosti mikrobiologické. 2018 ; 59 (4) : 134-135.

Bull. Českoslov. spol. mikrobiol.
ISSN 0009-0646
Medvik
Zdroj

Publikační typ
zprávy MeSH

Článek

Zápis zo schôdze výboru ČSSM zo dňa 4.12.2018, Praha

Bulletin Československé společnosti mikrobiologické. 2018 ; 59 (4) : 135-136.

Bull. Českoslov. spol. mikrobiol.
ISSN 0009-0646
Medvik
Zdroj

Publikační typ
zprávy MeSH

Článek

Synergy between azoles and 1,4-dihydropyridine derivative as an option to control fungal infections

Antonie van Leeuwenhoek. 2017 ; 110 (9) : 1219-1226. [pub] 20170607

Antonie Van Leeuwenhoek
ISSN 1572-9699
Medvik
Zdroj

With emerging fungal infections and developing resistance, there is a need for understanding the mechanisms of resistance as well as its clinical impact while planning the treatment strategies. Several approaches could be taken to overcome the problems arising from the management of fungal diseases. Besides the discovery of novel effective agents, one realistic alternative is to enhance the activity of existing agents. This strategy could be achieved by combining existing antifungal agents with other bioactive substances with known activity profiles (combination therapy). Azole antifungals are the most frequently used class of substances used to treat fungal infections. Fluconazole is often the first choice for antifungal treatment. The aim of this work was to study potential synergy between azoles and 1,4-dihydropyridine-2,3,5-tricarboxylate (termed derivative H) in order to control fungal infections. This article points out the synergy between azoles and newly synthesized derivative H in order to fight fungal infections. Experiments confirmed the role of derivative H as substrate/inhibitor of fungal transporter Cdr1p relating to increased sensitivity to fluconazole. These findings, plus decreased expression of ERG11, are responsible for the synergistic effect.