Reversal of antifungal resistance mediated by ABC efflux pumps from Candida albicans functionally expressed in yeast

2003 ◽  
Vol 22 (3) ◽  
pp. 291-300 ◽  
Author(s):  
M Schuetzer-Muehlbauer
Keyword(s):  
Candida Albicans ◽  
Efflux Pumps ◽  
Antifungal Resistance

scholarly journals A Combination Fluorescence Assay Demonstrates Increased Efflux Pump Activity as a Resistance Mechanism in Azole-Resistant Vaginal Candida albicans Isolates

2016 ◽  
Vol 60 (10) ◽  
pp. 5858-5866 ◽  
Author(s):  
Somanon Bhattacharya ◽  
Jack D. Sobel ◽  
Theodore C. White
Keyword(s):  
Candida Albicans ◽  
Efflux Pump ◽  
Pathogenic Fungus ◽  
Resistance Mechanism ◽  
Efflux Pumps ◽  
Resistant Isolate ◽  
Vaginal Infections ◽  
Content Type ◽  
Qrt Pcr ◽  
Pump Activity

ABSTRACTCandida albicansis a pathogenic fungus causing vulvovaginal candidiasis (VVC). Azole drugs, such as fluconazole, are the most common treatment for these infections. Recently, azole-resistant vaginalC. albicansisolates have been detected in patients with recurring and refractory vaginal infections. However, the mechanisms of resistance in vaginalC. albicansisolates have not been studied in detail. In oral and systemic resistant isolates, overexpression of the ABC transporters Cdr1p and Cdr2p and the major facilitator transporter Mdr1p is associated with resistance. Sixteen fluconazole-susceptible and 22 fluconazole-resistant vaginalC. albicansisolates were obtained, including six matched sets containing a susceptible and a resistant isolate, from individual patients. Using quantitative real-time reverse transcriptase PCR (qRT-PCR), 16 of 22 resistant isolates showed overexpression of at least one efflux pump gene, while only 1 of 16 susceptible isolates showed such overexpression. To evaluate the pump activity associated with overexpression, an assay that combined data from two separate fluorescent assays using rhodamine 6G and alanine β-naphthylamide was developed. The qRT-PCR results and activity assay results were in good agreement. This combination of two fluorescent assays can be used to study efflux pumps as resistance mechanisms in clinical isolates. These results demonstrate that efflux pumps are a significant resistance mechanism in vaginalC. albicansisolates.

Antifungal resistance-modifying multiplexing action of Momordica charantia protein and phosphorylated derivatives on the basis of growth-dependent gene coregulation in Candida albicans

2020 ◽  
Author(s):  
Qiao Yuan-Biao ◽  
Zhang Lan-Fang ◽  
Qiao Qi ◽  
Niu Jia-Hui ◽  
Ren Ze-Mei ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Translation Initiation ◽  
Low Dose ◽  
Fungal Growth ◽  
Momordica Charantia ◽  
Antifungal Resistance ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
High Dose ◽  
Rrna Processing

Abstract Fungal growth-dependent gene coregulation is strongly implicated in alteration of gene-encoding target proteases ruling with an antifungal resistance niche and biology of resistant mutants. On the basis of multi-alterative processes in this platform, the resistance-modifying strategy is designed in ketoconazole resistant Candida albicans and evaluated with less selective Momordica charantia protein and allosterically phosphorylated derivatives at the Thr102, Thr24 and Thr255 sites, respectively. We demonstrate absolutely chemo-sensitizing efficacy regarding stepwise-modifying resistance in sensitivity, by a load of only 26.23–40.00 μg/l agents in Sabouraud's dextrose broth. Five successive modifying-steps realize the decreasing of ketoconazole E-test MIC50 from 11.10 to a lower level than 0.10 mg/l. With the ketoconazole resistance-modifying, colony undergoes a high-frequency morphological switch between high ploidy (opaque) and small budding haploid (white). A cellular event in the first modifying-step associates with relatively slow exponential growth (ie, a 4-h delay)-dependent action, mediated by agents adsorption. Moreover, multiple molecular roles are coupled with intracellularly and extracellularly binding to ATP-dependent RNA helicase dbp6; the 0.08–2.45 fold upregulation of TATA-box-binding protein, rRNA-processing protein and translation initiation factor 5A; and the 7.52–55.33% decrease of cytochrome P450 lanosterol 14α-demethylase, glucan 1, 3-β glucosidase, candidapepsin-1 and 1-acylglycerol-3-phosphate O-acyltransferase. Spatial and temporal gene coregulation, in the transcription and translation initiation stages with rRNA-processing, is a new coprocessing platform enabling target protease attenuations for resistance-impairing. An updated resistance-modifying measure of these agents in the low-dose antifungal strategic design may provide opportunities to a virtually safe therapy that is in high dose-dependency. Lay Summary A new platform to modify resistance is fungal growth-dependent gene coregulation. MAP30 and phosphorylated derivatives are candidate resistance-modifying agents. Low-dose stepwise treatment absolutely modifies azole resistance in model fungus.

The yeast, the antifungal, and the wardrobe: a journey into antifungal resistance mechanisms of Candida tropicalis

2020 ◽  
Vol 66 (6) ◽  
pp. 377-388
Author(s):  
Jonathas Sales de Oliveira ◽  
Vandbergue Santos Pereira ◽  
Débora de Souza Collares Maia Castelo-Branco ◽  
Rossana de Aguiar Cordeiro ◽  
José Júlio Costa Sidrim ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Intensive Care ◽  
Candida Tropicalis ◽  
Clinical Management ◽  
Candida Species ◽  
Genetic Basis ◽  
Antifungal Susceptibility ◽  
Resistance Mechanisms ◽  
Antifungal Resistance ◽  
Resistant Strains

Candida tropicalis is a prominent non-Candida albicans Candida species involved in cases of candidemia, mainly causing infections in patients in intensive care units and (or) those presenting neutropenia. In recent years, several studies have reported an increase in the recovery rates of azole-resistant C. tropicalis isolates. Understanding C. tropicalis resistance is of great importance, since resistant strains are implicated in persistent or recurrent and breakthrough infections. In this review, we address the main mechanisms underlying C. tropicalis resistance to the major antifungal classes used to treat candidiasis. The main genetic basis involved in C. tropicalis antifungal resistance is discussed. A better understanding of the epidemiology of resistant strains and the mechanisms involved in C. tropicalis resistance can help improve diagnosis and assessment of the antifungal susceptibility of this Candida species to improve clinical management.

scholarly journals Ras1 involved in the antifungal resistance of Candida albicans and the inhibition of farnesol on the resistance of biofilms

2019 ◽  
Author(s):  
Xin Wei ◽  
Lulu Zuo ◽  
Shengyan Chen ◽  
Zhenzhen Zhang ◽  
Liuliu Jiang
Keyword(s):  
Candida Albicans ◽  
Molecular Mechanisms ◽  
Hyphal Growth ◽  
Antifungal Resistance ◽  
Morphological Observation ◽  
Inhibitory Effects ◽  
Wild Strains ◽  
Almost All ◽  
Candida Albicans Biofilms

Abstract Background: Farnesol enhances the susceptibility of Candida albicans biofilms to antifungals, while the molecular mechanisms of this behavior are poorly understood. RAS1 regulates the hyphal growth of C. albicans, and farnesol inhibited hyphal growth by RAS1 regulation, while the role of RAS1 in the resistance of C. albicans biofilms and the molecular mechanism of the RAS1 in the farnesol-relevant antifungal capacity to C. albicans biofilms is still unknown. The study hypothesized that Ras1 involved in the antifungal resistance of C. albicans and the inhibition of farnesol on the resistance of biofilms. Results: The susceptibility assays showed that RAS1 over-expressing strain (RAS1OE) increased the resistance of C.albicans in both planktonic and biofilm form to antifungals, while RAS1 deletion strain (ras1Δ/Δ) reduced that to antifungals. The SMIC50 of the antifungals were increased with the mature of the biofilms formed from the mutant and the wild strains. Exogenous farnesol decreased the resistance of RAS1OE to antifungals, including fluconazole, amphotericin B, itraconazole, caspofungin, terbinafine, 5-flurocytosine and nystatin. The inhibitory effects of farnesol on the antifungal resistance of the biofilms from the RAS1OE were in accordance to almost all of the growth phases. Moreover, exogenous farnesol decreased the resistance of biofilms from RAS1OE more obviously than that from the wild strains (P<0.05). In addition, Morphological observation showed that that RAS1OE increased hyphal growth the biofilms, while ras1Δ/Δ reduced that of the biofilms. Compare to the wild-type strain, the inhibitory effects of farnesol on hyphal growth were more obvious to the RAS1OE, while less obvious to the ras1Δ/Δ. Furthermore, farnesol reduced the level of Ras1 and the expression of RAS1 of the biofilms formed from the RAS1OE strain compared with those of the untreated controls at all studied phases. Moreover, farnesol reduced the level of Ras1 and the expression of RAS1 of the biofilms formed from RAS1OE more obviously than that from the wild strains. Conclusions: Ras1 involved in the antifungal resistance of Candida albicans, and the inhibition of farnesol on the resistance of biofilm.

Assessment of antifungal resistance and associated molecular mechanism in Candida albicans isolates from different cohorts of patients in North Indian state of Haryana

2020 ◽  
Vol 65 (4) ◽  
pp. 747-754
Author(s):  
Ashok Kumar ◽  
Remya Nair ◽  
Mohit Kumar ◽  
Atanu Banerjee ◽  
Arunaloke Chakrabarti ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Molecular Mechanism ◽  
Antifungal Resistance ◽  
Indian State

scholarly journals Impact of a Cross-Kingdom Signaling Molecule of Candida albicans on Acinetobacter baumannii Physiology

2015 ◽  
Vol 60 (1) ◽  
pp. 161-167 ◽  
Author(s):  
Xenia Kostoulias ◽  
Gerald L. Murray ◽  
Gustavo M. Cerqueira ◽  
Jason B. Kong ◽  
Farkad Bantun ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Cell Membrane ◽  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Defense Mechanism ◽  
Membrane Integrity ◽  
Efflux Pumps ◽  
Signaling Molecule ◽  
Content Type ◽  
Antagonistic Interactions

ABSTRACTMultidrug-resistant (MDR)Acinetobacter baumanniiis an opportunistic human pathogen that has become highly problematic in the clinical environment. Novel therapies are desperately required. To assist in identifying new therapeutic targets, the antagonistic interactions betweenA. baumanniiand the most common human fungal pathogen,Candida albicans, were studied. We have observed that theC. albicansquorum-sensing molecule, farnesol, has cross-kingdom interactions, affecting the viability ofA. baumannii. To gain an understanding of its mechanism, the transcriptional profile ofA. baumanniiexposed to farnesol was examined. Farnesol caused dysregulation of a large number of genes involved in cell membrane biogenesis, multidrug efflux pumps (AcrAB-like and AdeIJK-like), andA. baumanniivirulence traits such as biofilm formation (csuA,csuB, andompA) and motility (pilZandpilH). We also observed a strong induction in genes involved in cell division (minD,minE,ftsK,ftsB, andftsL). These transcriptional data were supported by functional assays showing that farnesol disruptsA. baumanniicell membrane integrity, alters cell morphology, and impairs virulence characteristics such as biofilm formation and twitching motility. Moreover, we showed thatA. baumanniiuses efflux pumps as a defense mechanism against this eukaryotic signaling molecule. Owing to its effects on membrane integrity, farnesol was tested to see if it potentiated the activity of the membrane-acting polymyxin antibiotic colistin. When coadministered, farnesol increased sensitivity to colistin for otherwise resistant strains. These data provide mechanistic understanding of the antagonistic interactions between diverse pathogens and may provide important insights into novel therapeutic strategies.

scholarly journals Phytosphingosine-1-Phosphate Is a Signaling Molecule Involved in Miconazole Resistance in Sessile Candida albicans Cells

2012 ◽  
Vol 56 (5) ◽  
pp. 2290-2294 ◽  
Author(s):  
Davy Vandenbosch ◽  
Anna Bink ◽  
Gilmer Govaert ◽  
Bruno P. A. Cammue ◽  
Hans J. Nelis ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Candida Albicans ◽  
Protective Effect ◽  
Cytoplasmic Membrane ◽  
Efflux Pumps ◽  
Signaling Molecule ◽  
Content Type ◽  
Gene Coding ◽  
High Doses ◽  
Sessile Cells

ABSTRACTPrevious research has shown that 1% to 10% of sessileCandida albicanscells survive treatment with high doses of miconazole (a fungicidal imidazole). In the present study, we investigated the involvement of sphingolipid biosynthetic intermediates in this survival. We observed that theLCB4gene, coding for the enzyme that catalyzes the phosphorylation of dihydrosphingosine and phytosphingosine, is important in governing the miconazole resistance of sessileSaccharomyces cerevisiaeandC. albicanscells. The addition of 10 nM phytosphingosine-1-phosphate (PHS-1-P) drastically reduced the intracellular miconazole concentration and significantly increased the miconazole resistance of a hypersusceptibleC. albicansheterozygousLCB4/lcb4mutant, indicating a protective effect of PHS-1-P against miconazole-induced cell death in sessile cells. At this concentration of PHS-1-P, we did not observe any effect on the fluidity of the cytoplasmic membrane. The protective effect of PHS-1-P was not observed when the efflux pumps were inhibited or when tested in a mutant without functional efflux systems. Also, the addition of PHS-1-P during miconazole treatment increased the expression levels of genes coding for efflux pumps, leading to the hypothesis that PHS-1-P acts as a signaling molecule and enhances the efflux of miconazole in sessileC. albicanscells.

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