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Antimicrobial Agents and Chemotherapy Apr 2022Candida auris is an emerging yeast pathogen with a remarkable ability to develop antifungal resistance, in particular to fluconazole and other azoles. Azole resistance...
Candida auris is an emerging yeast pathogen with a remarkable ability to develop antifungal resistance, in particular to fluconazole and other azoles. Azole resistance in C. auris was shown to result from different mechanisms, such as mutations in the target gene or gain-of-function (GOF) mutations in the transcription factor and overexpression of the drug transporter Cdr1. The roles of the transcription factor Mrr1 and of the drug transporter Mdr1 in azole resistance is still unclear. Previous works showed that deletion of or had no or little impact on azole susceptibility of C. auris. However, an amino acid substitution in Mrr1 (N647T) was identified in most C. auris isolates of clade III that were fluconazole resistant. This study aimed at investigating the role of the transcription factor Mrr1 in azole resistance of C. auris. While the mutation was always concomitant to hot spot mutations, deletion in one of these isolates only resulted in a modest decrease of azole MICs. However, introduction of the mutation in an azole-susceptible C. auris isolate from another clade with wild-type and alleles resulted in significant increase of fluconazole and voriconazole MICs. We demonstrated that this mutation resulted in reduced azole susceptibility via upregulation of the drug transporter and not . In conclusion, this work demonstrates that the Mrr1-Mdr1 axis may contribute to C. auris azole resistance by mechanisms that are independent from mutations and from upregulation.
Topics: Antifungal Agents; Azoles; Candida albicans; Candida auris; Drug Resistance, Fungal; Fluconazole; Fungal Proteins; Microbial Sensitivity Tests; Transcription Factors
PubMed: 35343781
DOI: 10.1128/aac.00067-22 -
Antimicrobial Agents and Chemotherapy Mar 2022Azoles, the most commonly used antifungal drugs, specifically inhibit the fungal lanosterol α-14 demethylase enzyme, which is referred to as Erg11. Inhibition of Erg11...
Azoles, the most commonly used antifungal drugs, specifically inhibit the fungal lanosterol α-14 demethylase enzyme, which is referred to as Erg11. Inhibition of Erg11 ultimately leads to a reduction in ergosterol production, an essential fungal membrane sterol. Many species, such as Candida albicans, develop mutations in this enzyme which reduces the azole binding affinity and results in increased resistance. Candida glabrata is also a pathogenic yeast that has low intrinsic susceptibility to azole drugs and easily develops elevated resistance. In C. glabrata, these azole resistant mutations typically cause hyperactivity of the Pdr1 transcription factor and rarely lie within the gene. Here, we generated C. glabrata mutations that were analogous to azole resistance alleles from C. albicans . Three different Erg11 forms (Y141H, S410F, and the corresponding double mutant (DM)) conferred azole resistance in C. glabrata with the DM Erg11 form causing the strongest phenotype. The DM Erg11 also induced cross-resistance to amphotericin B and caspofungin. Resistance caused by the DM allele of imposed a fitness cost that was not observed with hyperactive alleles. Crucially, the presence of the DM allele was sufficient to activate the Pdr1 transcription factor in the absence of azole drugs. Our data indicate that azole resistance linked to changes in activity can involve cellular effects beyond an alteration in this key azole target enzyme. Understanding the physiology linking ergosterol biosynthesis with Pdr1-mediated regulation of azole resistance is crucial for ensuring the continued efficacy of azole drugs against C. glabrata.
Topics: Alleles; Antifungal Agents; Azoles; Candida glabrata; DNA-Binding Proteins; Drug Resistance, Fungal; Fungal Proteins; Gene Expression Regulation, Fungal; Microbial Sensitivity Tests; Transcription Factors
PubMed: 35007132
DOI: 10.1128/AAC.02098-21 -
Microbiology Spectrum Feb 2022In the present study, and interactions of TOR inhibitor AZD8055 and azoles, including itraconazole, voriconazole, posaconazole and fluconazole, against a variety of...
In the present study, and interactions of TOR inhibitor AZD8055 and azoles, including itraconazole, voriconazole, posaconazole and fluconazole, against a variety of pathogenic fungi were investigated. A total of 69 isolates were studied via broth microdilution checkerboard technique, including 23 isolates of Aspergillus spp., 20 isolates of spp., 9 isolates of Cryptococcus neoformans complex, and 17 isolates of . The results revealed that AZD8055 individually did not exert any significant antifungal activity. However, synergistic effects between AZD8055 and itraconazole, voriconazole or posaconazole were observed in 23 (33%), 13 (19%) and 57 (83%) isolates, respectively, including azole-resistant A. fumigatus strains and spp., potentiating the efficacy of azoles. The combination effect of AZD8055 and fluconazole was investigated against non-auris spp. and C. neoformans complex. Synergism between AZD8055 and fluconazole was observed in six strains (60%) of spp., resulting in reversion of fluconazole resistance. Synergistic combinations resulted in 4-fold to 256-fold reduction of effective MICs of AZD8055 and azoles. No antagonism was observed. effects of AZD8055-azole combinations were evaluated by survival assay in Galleria mellonella model infected with A. fumigatus strain AF002, strain BMU00038, C. auris strain 383, C. albicans strain R15, and C. neoformans complex strain Z2. AZD8055 acted synergistically with azoles and significantly increased larvae survival ( < 0.05). In summary, the results suggested that AZD8055 combined with azoles may help to enhance the antifungal susceptibilities of azoles against pathogenic fungi and had the potential to overcome azole resistance issues. Limited options of antifungals and the emergence of drug resistance in fungal pathogens has been a multifaceted clinical challenge. Combination therapy represents a valuable alternative to antifungal monotherapy. The target of rapamycin (TOR), a conserved serine/threonine kinase from yeast to humans, participates in a signaling pathway that governs cell growth and proliferation in response to nutrient availability, growth factors, and environmental stimuli. AZD8055 is an orally bioavailable, potent, and selective TOR kinase inhibitor that binds to the ATP binding cleft of TOR kinase and inhibits both TORC1 and TORC2. Synergism between AZD8055 and azoles suggested that the concomitant application of AZD8055 and azoles may help to enhance azole therapeutic efficacy and impede azole resistance. TOR inhibitor with fungal specific target is promising to be served as combination regimen with azoles.
Topics: Antifungal Agents; Aspergillus; Azoles; Candida; Candida albicans; Drug Resistance, Fungal; Exophiala; Fungi; Humans; Itraconazole; Microbial Sensitivity Tests; Morpholines; Sirolimus; TOR Serine-Threonine Kinases; Triazoles; Voriconazole
PubMed: 35019705
DOI: 10.1128/spectrum.02007-21 -
Cells May 2020Azole fungicides, especially triazole compounds, are widely used in agriculture and as pharmaceuticals. For a considerable number of agricultural azole fungicides, the... (Review)
Review
Azole fungicides, especially triazole compounds, are widely used in agriculture and as pharmaceuticals. For a considerable number of agricultural azole fungicides, the liver has been identified as the main target organ of toxicity. A number of previous studies points towards an important role of nuclear receptors such as the constitutive androstane receptor (CAR), the pregnane-X-receptor (PXR), or the aryl hydrocarbon receptor (AHR), within the molecular pathways leading to hepatotoxicity of these compounds. Nuclear receptor-mediated hepatic effects may comprise rather adaptive changes such as the induction of drug-metabolizing enzymes, to hepatocellular hypertrophy, histopathologically detectable fatty acid changes, proliferation of hepatocytes, and the promotion of liver tumors. Here, we present a comprehensive review of the current knowledge of the interaction of major agricultural azole-class fungicides with the three nuclear receptors CAR, PXR, and AHR in vivo and in vitro. Nuclear receptor activation profiles of the azoles are presented and related to histopathological findings from classic toxicity studies. Important issues such as species differences and multi-receptor agonism and the consequences for data interpretation and risk assessment are discussed.
Topics: Animals; Azoles; Fungicides, Industrial; Humans; Liver; Pharmaceutical Preparations; Receptors, Cytoplasmic and Nuclear; Xenobiotics
PubMed: 32403288
DOI: 10.3390/cells9051192 -
Journal of Global Antimicrobial... Jun 2022Infections due to Candida species represent a serious threat to healthcare facilities. Only a few classes of antifungal agents are available, and the rapid emergence of...
OBJECTIVES
Infections due to Candida species represent a serious threat to healthcare facilities. Only a few classes of antifungal agents are available, and the rapid emergence of (multi)drug resistance eliminates effective treatment options for successful patient outcome. Topically applied antiseptics may represent a suitable tool for infection control and local therapy. This study aimed to investigate the in vitro efficacy of the widely used antiseptic octenidine (OCT) against clinical isolates of emerging azole-, echinocandin- and multi-resistant Candida albicans and Candida glabrata.
METHODS
The antifungal activity of different concentrations of OCT ranging from 0.001% to 0.05% and of OCT-containing ready-to-use products was determined against well-characterised (multidrug) resistant C. albicans and C. glabrata isolates, including susceptible wild-type strains. Quantitative suspension tests were performed under "clean conditions" (0.3 g/L bovine serum albumin) and under "dirty conditions" (3 g/L albumin + 3 mL/L defibrinated sheep blood) as well as various contact times (30 s, 1 min, 2 min) according to EN13624:2013.
RESULTS
Even in the presence of a high organic load, pure OCT at 0.05% and a contact time of 30 s was fully effective for all Candida strains, with growth kinetics indicating a time- and concentration-dependent activity. Importantly, commercially available OCT-based products achieved the required reduction of ≥4 log for all Candida isolates under the most challenging dirty conditions within two minutes, which makes them suitable for routine clinical use.
CONCLUSION
These results encourage consideration of the well-tolerated antiseptic molecule OCT in the eradication of emerging (multidrug) resistant C. albicans and C. glabrata.
Topics: Animals; Anti-Infective Agents, Local; Antifungal Agents; Azoles; Candida; Candida albicans; Candida glabrata; Echinocandins; Imines; Microbial Sensitivity Tests; Pyridines; Sheep
PubMed: 35134551
DOI: 10.1016/j.jgar.2022.01.028 -
Applied and Environmental Microbiology Apr 2024is an important global fungal pathogen of humans. Azole drugs are among the most effective treatments for infection. Azoles are also widely used in agriculture as...
is an important global fungal pathogen of humans. Azole drugs are among the most effective treatments for infection. Azoles are also widely used in agriculture as fungicides against fungal pathogens of crops. Azole-resistant has been increasing in Europe and Asia for two decades where clinical resistance is thought to be driven by agricultural use of azole fungicides. The most prevalent mechanisms of azole resistance in are tandem repeats (TR) in the promoter coupled with mutations in the coding region which result in resistance to multiple azole drugs (pan-azole resistance). Azole-resistant has been isolated from patients in the United States (U.S.), but little is known about its environmental distribution. To better understand the distribution of azole-resistant in the U.S., we collected isolates from agricultural sites in eight states and tested 202 isolates for sensitivity to azoles. We found azole-resistant in agricultural environments in seven states showing that it is widespread in the U.S. We sequenced environmental isolates representing the range of U.S. sample sites and compared them with publicly available environmental worldwide isolates in phylogenetic, principal component, and ADMIXTURE analyses. We found worldwide isolates fell into three clades, and TR-based pan-azole resistance was largely in a single clade that was strongly associated with resistance to multiple agricultural fungicides. We also found high levels of gene flow indicating recombination between clades highlighting the potential for azole-resistance to continue spreading in the U.S.IMPORTANCE is a fungal pathogen of humans that causes over 250,000 invasive infections each year. It is found in soils, plant debris, and compost. Azoles are the first line of defense antifungal drugs against . Azoles are also used as agricultural fungicides to combat other fungi that attack plants. Azole-resistant has been a problem in Europe and Asia for 20 years and has recently been reported in patients in the United States (U.S.). Until this study, we did not know much about azole-resistant in agricultural settings in the U.S. In this study, we isolated azole-resistant from multiple states and compared it to isolates from around the world. We show that which is resistant to azoles and to other strictly agricultural fungicides is widespread in the U.S.
Topics: Humans; United States; Aspergillus fumigatus; Fungicides, Industrial; Azoles; Phylogeny; Drug Resistance, Fungal; Antifungal Agents; Fungal Proteins; Microbial Sensitivity Tests
PubMed: 38557086
DOI: 10.1128/aem.01782-23 -
Nature Communications Jan 2021Azoles are five-membered heterocycles often found in the backbones of peptidic natural products and synthetic peptidomimetics. Here, we report a method of ribosomal...
Azoles are five-membered heterocycles often found in the backbones of peptidic natural products and synthetic peptidomimetics. Here, we report a method of ribosomal synthesis of azole-containing peptides involving specific ribosomal incorporation of a bromovinylglycine derivative into the nascent peptide chain and its chemoselective conversion to a unique azole structure. The chemoselective conversion was achieved by posttranslational dehydrobromination of the bromovinyl group and isomerization in aqueous media under fairly mild conditions. This method enables us to install exotic azole groups, oxazole and thiazole, at designated positions in the peptide chain with both linear and macrocyclic scaffolds and thereby expand the repertoire of building blocks in the mRNA-templated synthesis of designer peptides.
Topics: Azoles; Biomimetics; Drug Design; Peptide Biosynthesis; Peptides; Peptidomimetics; Protein Processing, Post-Translational
PubMed: 33514734
DOI: 10.1038/s41467-021-20992-0 -
Mycoses Apr 2022Azole resistance complicates treatment of patients with invasive aspergillosis with an increased mortality. Azole resistance in Aspergillus fumigatus is a growing...
BACKGROUND
Azole resistance complicates treatment of patients with invasive aspergillosis with an increased mortality. Azole resistance in Aspergillus fumigatus is a growing problem and associated with human and environmental azole use. Denmark has a considerable and highly efficient agricultural sector. Following reports on environmental azole resistance in A. fumigatus from Danish patients, the ministry of health requested a prospective national surveillance of azole-resistant A. fumigatus and particularly that of environmental origin.
OBJECTIVES
To present the data from the first 2 years of the surveillance programme.
METHODS
Unique isolates regarded as clinically relevant and any A. fumigatus isolated on a preferred weekday (background samples) were included. EUCAST susceptibility testing was performed and azole-resistant isolates underwent cyp51A gene sequencing.
RESULTS
The azole resistance prevalence was 6.1% (66/1083) at patient level. The TR /L98H prevalence was 3.6% (39/1083) and included the variants TR /L98H, TR /L98H and TR /L98H/S297T/F495I. Resistance caused by other Cyp51A variants accounted for 1.3% (14/1083) and included G54R, P216S, F219L, G54W, M220I, M220K, M220R, G432S, G448S and Y121F alterations. Non-Cyp51A-mediated resistance accounted for 1.2% (13/1083). Proportionally, TR /L98H, other Cyp51A variants and non-Cyp51A-mediated resistance accounted for 59.1% (39/66), 21.2% (14/66) and 19.7% (13/66), respectively, of all resistance. Azole resistance was detected in all five regions in Denmark, and TR /L98H specifically, in four of five regions during the surveillance period.
CONCLUSION
The azole resistance prevalence does not lead to a change in the initial treatment of aspergillosis at this point, but causes concern and leads to therapeutic challenges in the affected patients.
Topics: Antifungal Agents; Aspergillus fumigatus; Azoles; Denmark; Drug Resistance, Fungal; Fungal Proteins; Humans; Microbial Sensitivity Tests; Prospective Studies
PubMed: 35104010
DOI: 10.1111/myc.13426 -
Journal of Clinical Microbiology Dec 2018The purpose of this review is to critically analyze published data evaluating the impact of azole pharmacokinetic and pharmacodynamic parameters, MICs, and species on... (Review)
Review
The purpose of this review is to critically analyze published data evaluating the impact of azole pharmacokinetic and pharmacodynamic parameters, MICs, and species on clinical outcomes in patients with candidemia. Clinical breakpoints (CBPs) for fluconazole and voriconazole, which are used to determine susceptibility, have been defined by the Clinical and Laboratory Standards Institute (CLSI) for species. Studies evaluating the relationship between treatment efficacy and susceptibility, as well as the pharmacodynamic targets, have been conducted in patients treated with fluconazole for candidemia; however, for species other than and , and for other forms of invasive candidiasis, data remain limited and randomized trials are not available. Limited data evaluating these relationships with voriconazole are available. While pharmacodynamic targets for posaconazole and isavuconazole have been proposed based upon studies conducted in murine models, CBPs have not been established by CLSI. Fluconazole remains an important antifungal agent for the treatment of candidemia, and data supporting its use based on susceptibility are growing, particularly for and Further investigation is needed to establish the roles of voriconazole, posaconazole, and isavuconazole in the treatment of candidemia and for all agents in the treatment of other forms of invasive candidiasis.
Topics: Animals; Antifungal Agents; Azoles; Candida; Candidemia; Fluconazole; Humans; Microbial Sensitivity Tests; Species Specificity; Treatment Outcome
PubMed: 30135234
DOI: 10.1128/JCM.01072-18 -
Antimicrobial Agents and Chemotherapy Dec 2020The limited therapeutic options and the recent emergence of multidrug-resistant species present a significant challenge to human medicine and underscore the need for...
The limited therapeutic options and the recent emergence of multidrug-resistant species present a significant challenge to human medicine and underscore the need for novel therapeutic approaches. Drug repurposing appears as a promising tool to augment the activity of current azole antifungals, especially against multidrug-resistant In this study, we evaluated the fluconazole chemosensitization activities of 1,547 FDA-approved drugs and clinical molecules against azole-resistant This led to the discovery that lopinavir, an HIV protease inhibitor, is a potent agent capable of sensitizing to the effect of azole antifungals. At a therapeutically achievable concentration, lopinavir exhibited potent synergistic interactions with azole drugs, particularly with itraconazole against (fractional inhibitory concentration index [ΣFICI] ranged from 0.04 to 0.09). Additionally, the lopinavir/itraconazole combination enhanced the survival rate of -infected by 90% and reduced the fungal burden in infected nematodes by 88.5% (0.05) relative to that of the untreated control. Furthermore, lopinavir enhanced the antifungal activity of itraconazole against other medically important species, including , , , and Comparative transcriptomic profiling and mechanistic studies revealed that lopinavir was able to significantly interfere with the glucose permeation and ATP synthesis. This compromised the efflux ability of and consequently enhanced the susceptibility to azole drugs, as demonstrated by Nile red efflux assays. Altogether, these findings present lopinavir as a novel, potent, and broad-spectrum azole-chemosensitizing agent that warrants further investigation against recalcitrant infections.
Topics: Antifungal Agents; Azoles; Candida; Fluconazole; Humans; Lopinavir; Microbial Sensitivity Tests; Pharmaceutical Preparations
PubMed: 33046487
DOI: 10.1128/AAC.00684-20