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Brettner L, Ho WC, Schmidlin K, Apodaca S, Eder R, Geiler-Samerotte K. Challenges and potential solutions for studying the genetic and phenotypic architecture of adaptation in microbes. Curr Opin Genet Dev 2022; 75:101951. [PMID: 35797741 DOI: 10.1016/j.gde.2022.101951] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 06/01/2022] [Accepted: 06/14/2022] [Indexed: 11/29/2022]
Abstract
All organisms are defined by the makeup of their DNA. Over billions of years, the structure and information contained in that DNA, often referred to as genetic architecture, have been honed by a multitude of evolutionary processes. Mutations that cause genetic elements to change in a way that results in beneficial phenotypic change are more likely to survive and propagate through the population in a process known as adaptation. Recent work reveals that the genetic targets of adaptation are varied and can change with genetic background. Further, seemingly similar adaptive mutations, even within the same gene, can have diverse and unpredictable effects on phenotype. These challenges represent major obstacles in predicting adaptation and evolution. In this review, we cover these concepts in detail and identify three emerging synergistic solutions: higher-throughput evolution experiments combined with updated genotype-phenotype mapping strategies and physiological models. Our review largely focuses on recent literature in yeast, and the field seems to be on the cusp of a new era with regard to studying the predictability of evolution.
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Daneshnia F, Hilmioğlu Polat S, Ilkit M, Shor E, de Almeida Júnior JN, Favarello LM, Colombo AL, Arastehfar A, Perlin DS. Determinants of fluconazole resistance and the efficacy of fluconazole and milbemycin oxim combination against Candida parapsilosis clinical isolates from Brazil and Turkey. FRONTIERS IN FUNGAL BIOLOGY 2022; 3:906681. [PMID: 37746198 PMCID: PMC10512262 DOI: 10.3389/ffunb.2022.906681] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 07/11/2022] [Indexed: 09/26/2023]
Abstract
Fluconazole-resistant Candida parapsilosis (FLZR-CP) outbreaks are a growing public health concern and have been reported in numerous countries. Patients infected with FLZR-CP isolates show fluconazole therapeutic failure and have a significantly increased mortality rate. Because fluconazole is the most widely used antifungal agent in most regions with outbreaks, it is paramount to restore its antifungal activity. Milbemycin oxim (MOX), a well-known canine endectocide, is a potent efflux pump inhibitor that significantly potentiates the activity of fluconazole against FLZR C. glabrata and C. albicans. However, the FLZ-MOX combination has not been tested against FLZR-CP isolates, nor is it known whether MOX may also potentiate the activity of echinocandins, a different class of antifungal drugs. Furthermore, the extent of involvement of efflux pumps CDR1 and MDR1 and ergosterol biosynthesis enzyme ERG11 and their link with gain-of-function (GOF) mutations in their transcription regulators (TAC1, MRR1, and UPC2) are poorly characterized among FLZR-CP isolates. We analyzed 25 C. parapsilosis isolates collected from outbreaks in Turkey and Brazil by determining the expression levels of CDR1, MDR1, and ERG11, examining the presence of potential GOF mutations in their transcriptional regulators, and assessing the antifungal activity of FLZ-MOX and micafungin-MOX against FLZR and multidrug-resistant (MDR) C. parapsilosis isolates. ERG11 was found to be universally induced by fluconazole in all isolates, while expression of MDR1 was unchanged. Whereas mutations in MRR1 and UPC2 were not detected, CDR1 was overexpressed in three Brazilian FLZR-CP isolates, which also carried a novel TAC1L518F mutation. Of these three isolates, one showed increased basal expression of CDR1, while the other two overexpressed CDR1 only in the presence of fluconazole. Interestingly, MOX showed promising antifungal activity against FLZR isolates, reducing the FLZ MIC 8- to 32-fold. However, the MOX and micafungin combination did not exert activity against an MDR C. parapsilosis isolate. Collectively, our study documents that the mechanisms underpinning FLZR are region specific, where ERG11 mutations were the sole mechanism of FLZR in Turkish FLZR-CP isolates, while simultaneous overexpression of CDR1 was observed in some Brazilian counterparts. Moreover, MOX and fluconazole showed potent synergistic activity, while the MOX-micafungin combination showed no synergy.
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Affiliation(s)
- Farnaz Daneshnia
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, United States
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, Netherlands
| | | | - Macit Ilkit
- Division of Mycology, Faculty of Medicine, Çukurova University, Adana, Turkey
| | - Erika Shor
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, United States
- Hackensack Meridian School of Medicine, Nutley, NJ, United States
| | - João Nobrega de Almeida Júnior
- Laboratorio de Micologia Medica (LIM 53), Instituto de Medicina Tropical, Universidade de São Paulo, São Paulo, Brazil
- Laboratório Central (LIM 03), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Larissa M. Favarello
- Department of Medicine, Division of Infectious Diseases, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Arnaldo Lopes Colombo
- Department of Medicine, Division of Infectious Diseases, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Amir Arastehfar
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, United States
| | - David S. Perlin
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, United States
- Hackensack Meridian School of Medicine, Nutley, NJ, United States
- Georgetown University Lombardi Comprehensive Cancer Center, Washington, DC, United States
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Odiba AS, Durojaye OA, Ezeonu IM, Mgbeahuruike AC, Nwanguma BC. A New Variant of Mutational and Polymorphic Signatures in the ERG11 Gene of Fluconazole-Resistant Candida albicans. Infect Drug Resist 2022; 15:3111-3133. [PMID: 35747333 PMCID: PMC9213107 DOI: 10.2147/idr.s360973] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 06/03/2022] [Indexed: 11/23/2022] Open
Abstract
Background Resistance to antifungal drugs for treating Candida infections remains a major concern globally despite the range of medications available. Most of these drugs target key proteins essential to the life cycle of the organism. An enzyme essential for fungal cell membrane integrity, lanosterol 14–α demethylase (CYP51), is encoded by the ERG11 gene in Candida species. This enzyme is the target of azole–based drugs. The organism has, however, devised molecular adaptations to evade the activity of these drugs. Materials and Methods Classical methods were employed to characterize clinical isolates sampled from women and dogs of reproductive age. For fluconazole efficacy studies, CLSI guidelines on drug susceptibility testing were used. To understand the susceptibility pattern, various molecular and structural analytic approaches, including sequencing, in silico site-directed mutagenesis, and protein-ligand profiling, were applied to the ERG11 gene and CYP51 protein sequences. Several platforms, comprising Clustal Omega, Pymol plugin manager, Pymol molecular visualizer, Chimera–curated Dynameomics rotamer library, protein–ligand interaction profiler, Charmm36 force field, GROMACS, Geneious, and Mega7, were employed for this analysis. Results The following Candida species distribution was obtained: 37.84% C. albicans, 8.12% C. glabrata, 10.81% C. krusei, 5.41% C. tropicalis, and 37.84% of other unidentified Candida species. Two codons in the nucleotide sequence of the wild-type (CTC and CCA) coding for LEU–370 and PRO–375, respectively, were mutated to L370S and P375H in the resistant strain. The mutation stabilized the protein at the expense of the heme moiety. We found that the susceptible isolate from dogs (Can–iso–029/dog) is closely related to the most resistant isolate from humans. Conclusion Taken together, our results showed new mutations in the heme-binding pocket of caCYP51 that explain the resistance to fluconazole exhibited by the Candida isolates. So far, the L370S and P375H resistance-linked mutations have not been previously reported.
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Affiliation(s)
- Arome Solomon Odiba
- Department of Biochemistry, Faculty of Biological Sciences, University of Nigeria, Nsukka, Enugu State, 410001, Nigeria.,Department of Molecular Genetics and Biotechnology, University of Nigeria, Nsukka, Enugu State, 410001, Nigeria
| | - Olanrewaju Ayodeji Durojaye
- Department of Chemical Sciences, Coal City University, Emene, Enugu State, Nigeria.,Department of Molecular and Cell Biology, University of Science and Technology of China, Hefei, Anhui, 230026, People's Republic of China.,MOE Key Laboratory of Membraneless Organelle and Cellular Dynamics, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, People's Republic of China
| | - Ifeoma Maureen Ezeonu
- Department of Microbiology, Faculty of Biological Sciences, University of Nigeria, Nsukka, Enugu State, 410001, Nigeria
| | - Anthony Christian Mgbeahuruike
- Department of Veterinary Pathology and Microbiology, Faculty of Veterinary Medicine, University of Nigeria, Nsukka, Enugu State, 410001, Nigeria
| | - Bennett Chima Nwanguma
- Department of Biochemistry, Faculty of Biological Sciences, University of Nigeria, Nsukka, Enugu State, 410001, Nigeria.,Department of Molecular Genetics and Biotechnology, University of Nigeria, Nsukka, Enugu State, 410001, Nigeria
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Hoenigl M, Sprute R, Arastehfar A, Perfect JR, Lass-Flörl C, Bellmann R, Prattes J, Thompson GR, Wiederhold NP, Al Obaidi MM, Willinger B, Arendrup MC, Koehler P, Oliverio M, Egger M, Schwartz IS, Cornely OA, Pappas PG, Krause R. Invasive candidiasis: Investigational drugs in the clinical development pipeline and mechanisms of action. Expert Opin Investig Drugs 2022; 31:795-812. [PMID: 35657026 PMCID: PMC9339492 DOI: 10.1080/13543784.2022.2086120] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
INTRODUCTION The epidemiology of invasive Candida infections is evolving. Infections caused by non-albicans Candida spp. are increasing; however, the antifungal pipeline is more promising than ever and is enriched with repurposed drugs and agents that have new mechanisms of action. Despite progress, unmet needs in the treatment of invasive candidiasis remain and there are still too few antifungals that can be administered orally or that have CNS penetration. AREAS COVERED The authors shed light on those antifungal agents active against Candida that are in late-stage clinical development. Mechanisms of action and key pharmacokinetic and pharmacodynamic properties are discussed. Insights are offered on the potential future roles of the investigational agents MAT-2203, oteseconazole, ATI-2307, VL-2397, NP-339, and the repurposed drug miltefosine. EXPERT OPINION Ibrexafungerp and fosmanogepix have novel mechanisms of action and will provide effective options for the treatment of Candida infections (including those caused by multiresistant Candida spp). Rezafungin, an echinocandin with an extended half-life allowing for once weekly administration, will be particularly valuable for outpatient treatment and prophylaxis. Despite this, there is an urgent need to garner clinical data on investigational drugs, especially in the current rise of azole-resistant and multi-drug resistant Candida spp.
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Affiliation(s)
- Martin Hoenigl
- Division of Infectious Diseases, Excellence Center for Medical Mycology (ECMM), Medical University of Graz, Graz, Austria.,Division of Infectious Diseases and Global Public Health, Department of Medicine, University of California San Diego, La Jolla, CA.,Clinical and Translational Fungal - Working Group, University of California San Diego, La Jolla, CA
| | - Rosanne Sprute
- University of Cologne, Faculty of Medicine and University Hospital Cologne, Department I of Internal Medicine, Excellence Center for Medical Mycology (ECMM), Cologne, Germany.,University of Cologne, Faculty of Medicine and University Hospital Cologne, Chair Translational Research, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne, Germany.,German Centre for Infection Research (DZIF), Partner Site Bonn-Cologne, Cologne, Germany
| | - Amir Arastehfar
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, 07110, USA
| | - John R Perfect
- Division of Infectious Diseases and Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | - Cornelia Lass-Flörl
- Institute of Hygiene and Medical Microbiology, Excellence Center for Medical Mycology (ECMM), Medical University of Innsbruck, Innsbruck, Austria
| | - Romuald Bellmann
- Clinical Pharmacokinetics Unit, Division of Intensive Care and Emergency Medicine, Department of Internal Medicine I, Medical University of Innsbruck, Innsbruck, Austria
| | - Juergen Prattes
- Division of Infectious Diseases, Excellence Center for Medical Mycology (ECMM), Medical University of Graz, Graz, Austria.,University of Cologne, Faculty of Medicine and University Hospital Cologne, Department I of Internal Medicine, Excellence Center for Medical Mycology (ECMM), Cologne, Germany
| | - George R Thompson
- Department of Internal Medicine, Division of Infectious Diseases and Department of Medical Microbiology and Immunology, University of California Davis Medical Center
| | - Nathan P Wiederhold
- Department of Pathology and Laboratory Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Mohanad M Al Obaidi
- Division of Infectious Diseases, University of Arizona College of Medicine, Tucson, AZ, USA
| | - Birgit Willinger
- Division of Clinical Microbiology, Department of Laboratory Medicine, Medical University of Vienna, Austria
| | - Maiken C Arendrup
- Unit of Mycology, Statens Serum Institut, Copenhagen, Denmark.,Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark.,Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Philipp Koehler
- University of Cologne, Faculty of Medicine and University Hospital Cologne, Department I of Internal Medicine, Excellence Center for Medical Mycology (ECMM), Cologne, Germany.,University of Cologne, Faculty of Medicine and University Hospital Cologne, Chair Translational Research, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne, Germany
| | - Matteo Oliverio
- University of Cologne, Faculty of Medicine and University Hospital Cologne, Department I of Internal Medicine, Excellence Center for Medical Mycology (ECMM), Cologne, Germany.,University of Cologne, Faculty of Medicine and University Hospital Cologne, Chair Translational Research, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne, Germany
| | - Matthias Egger
- Division of Infectious Diseases, Excellence Center for Medical Mycology (ECMM), Medical University of Graz, Graz, Austria
| | - Ilan S Schwartz
- Division of Infectious Diseases, Department of Medicine, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta
| | - Oliver A Cornely
- University of Cologne, Faculty of Medicine and University Hospital Cologne, Department I of Internal Medicine, Excellence Center for Medical Mycology (ECMM), Cologne, Germany.,University of Cologne, Faculty of Medicine and University Hospital Cologne, Chair Translational Research, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Cologne, Germany.,German Centre for Infection Research (DZIF), Partner Site Bonn-Cologne, Cologne, Germany.,University of Cologne, Faculty of Medicine and University Hospital Cologne, Clinical Trials Centre Cologne (ZKS Köln), Cologne, Germany
| | - Peter G Pappas
- Department of Medicine, Division of Infectious Diseases, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Robert Krause
- Division of Infectious Diseases, Excellence Center for Medical Mycology (ECMM), Medical University of Graz, Graz, Austria
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Lotfali E, Erami M, Fattahi M, Nemati H, Ghasemi Z, Mahdavi E. Analysis of molecular resistance to azole and echinocandin in Candida species in patients with vulvovaginal candidiasis. Curr Med Mycol 2022; 8:1-7. [PMID: 36654793 PMCID: PMC9825790 DOI: 10.18502/cmm.8.2.10326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 01/29/2022] [Accepted: 03/19/2022] [Indexed: 11/15/2022] Open
Abstract
Background and Purpose Vulvovaginal candidiasis (VVC) is considered the most common mucosal infection caused by Candida species. Azoles were considered the first-line treatment for VVC or recurrent vulvovaginal candidiasis (RVVC) in both healthy and immunocompromised populations. Recently, azole-resistant isolates, especially among non-albicans Candida samples have been encountered. This study aimed to evaluate the antifungal susceptibility profile of Candida spp. isolated from VVC or RVVC patients and assess the molecular resistance mechanism of Candida spp. to azole and echinocandin. Materials and Methods Point mutation analysis was performed on the ERG11 and FKS candidate genes of azole- and caspofungin-resistant Candida albicans and Candida glabrata isolates. Real-time polymerase chain reaction was performed to gain insight into the differential expression of ERG11 mRNA. Results Variations in the amino acid D116E were observed in fluconazole- and itraconazole-resistant C. albicans strains, and changes in amino acid E517Q were observed only in fluconazole-resistant C. albicans strains. No polymorphisms were observed in the complete sequence alignment of the ERG11 gene in one azole-resistant C. glabrata isolate. The mutation triggered the changes in the amino acid serine in the reference gene FKS1 by the leucine at position 642 (S642L) of the isolates. Conclusion In patients with persistent or recurrent infection, the choice of an antifungal agent is often challenging and requires monitoring of the antifungal susceptibility of the colonizing strain. C. albicans and C. glabrata isolates can be resistant to azole and caspofungin antifungal agents without mutations in the ERG 11 and HS1 regions of the FKS1 gene.
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Affiliation(s)
- Ensieh Lotfali
- Department of Medical Parasitology and Mycology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mahzad Erami
- Kashan Shahid Beheshti Hospital, Kashan University of Medical Sciences, Kashan, Iran
| | - Mahsa Fattahi
- Center for Research and Training in Skin Diseases and Leprosy, Tehran University of Medical Sciences, Tehran, Iran
| | - Houshang Nemati
- Fertility and Infertility Research Center, Health Technology Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Zeinab Ghasemi
- Razi Hospital, Tehran University of Medical Science, Tehran, Iran
| | - Elham Mahdavi
- Department of Medical Parasitology, School of Medicine, Zabol University of Medical Sciences, Zabol, Iran
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Boahen A, Than LTL, Loke YL, Chew SY. The Antibiofilm Role of Biotics Family in Vaginal Fungal Infections. Front Microbiol 2022; 13:787119. [PMID: 35694318 PMCID: PMC9179178 DOI: 10.3389/fmicb.2022.787119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 04/25/2022] [Indexed: 11/15/2022] Open
Abstract
“Unity in strength” is a notion that can be exploited to characterize biofilms as they bestow microbes with protection to live freely, escalate their virulence, confer high resistance to therapeutic agents, and provide active grounds for the production of biofilms after dispersal. Naturally, fungal biofilms are inherently resistant to many conventional antifungals, possibly owing to virulence factors as their ammunitions that persistently express amid planktonic transition to matured biofilm state. These ammunitions include the ability to form polymicrobial biofilms, emergence of persister cells post-antifungal treatment and acquisition of resistance genes. One of the major disorders affecting vaginal health is vulvovaginal candidiasis (VVC) and its reoccurrence is termed recurrent VVC (RVVC). It is caused by the Candida species which include Candida albicans and Candida glabrata. The aforementioned Candida species, notably C. albicans is a biofilm producing pathogen and habitually forms part of the vaginal microbiota of healthy women. Latest research has implicated the role of fungal biofilms in VVC, particularly in the setting of treatment failure and RVVC. Consequently, a plethora of studies have advocated the utilization of probiotics in addressing these infections. Specifically, the excreted or released compounds of probiotics which are also known as postbiotics are being actively researched with vast potential to be used as therapeutic options for the treatment and prevention of VVC and RVVC. These potential sources of postbiotics are harnessed due to their proven antifungal and antibiofilm. Hence, this review discusses the role of Candida biofilm formation in VVC and RVVC. In addition, we discuss the application of pro-, pre-, post-, and synbiotics either individually or in combined regimen to counteract the abovementioned problems. A clear understanding of the role of biofilms in VVC and RVVC will provide proper footing for further research in devising novel remedies for prevention and treatment of vaginal fungal infections.
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Baker KM, Hoda S, Saha D, Gregor JB, Georgescu L, Serratore ND, Zhang Y, Cheng L, Lanman NA, Briggs SD. The Set1 Histone H3K4 Methyltransferase Contributes to Azole Susceptibility in a Species-Specific Manner by Differentially Altering the Expression of Drug Efflux Pumps and the Ergosterol Gene Pathway. Antimicrob Agents Chemother 2022; 66:e0225021. [PMID: 35471041 PMCID: PMC9112889 DOI: 10.1128/aac.02250-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Fungal infections are a major health concern because of limited antifungal drugs and development of drug resistance. Candida can develop azole drug resistance by overexpression of drug efflux pumps or mutating ERG11, the target of azoles. However, the role of epigenetic histone modifications in azole-induced gene expression and drug resistance is poorly understood in Candida glabrata. In this study, we show that Set1 mediates histone H3K4 methylation in C. glabrata. In addition, loss of SET1 and histone H3K4 methylation increases azole susceptibility in both C. glabrata and S. cerevisiae. This increase in azole susceptibility in S. cerevisiae and C. glabrata strains lacking SET1 is due to distinct mechanisms. For S. cerevisiae, loss of SET1 decreased the expression and function of the efflux pump Pdr5, but not ERG11 expression under azole treatment. In contrast, loss of SET1 in C. glabrata does not alter expression or function of efflux pumps. However, RNA sequencing revealed that C. glabrata Set1 is necessary for azole-induced expression of all 12 genes in the late ergosterol biosynthesis pathway, including ERG11 and ERG3. Furthermore, chromatin immunoprecipitation analysis shows histone H3K4 trimethylation increases upon azole-induced ERG gene expression. In addition, high performance liquid chromatography analysis indicated Set1 is necessary for maintaining proper ergosterol levels under azole treatment. Clinical isolates lacking SET1 were also hypersusceptible to azoles which is attributed to reduced ERG11 expression but not defects in drug efflux. Overall, Set1 contributes to azole susceptibility in a species-specific manner by altering the expression and consequently disrupting pathways known for mediating drug resistance.
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Affiliation(s)
- Kortany M. Baker
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, USA
| | - Smriti Hoda
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, USA
| | - Debasmita Saha
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, USA
| | - Justin B. Gregor
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, USA
| | - Livia Georgescu
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, USA
| | - Nina D. Serratore
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, USA
| | - Yueping Zhang
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, USA
| | - Lizhi Cheng
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, USA
| | - Nadia A. Lanman
- Purdue University Center for Cancer Research, Purdue University, West Lafayette, Indiana, USA
- Department of Comparative Pathobiology, Purdue University, West Lafayette, Indiana, USA
| | - Scott D. Briggs
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, USA
- Purdue University Center for Cancer Research, Purdue University, West Lafayette, Indiana, USA
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Espinel-Ingroff A. Commercial Methods for Antifungal Susceptibility Testing of Yeasts: Strengths and Limitations as Predictors of Resistance. J Fungi (Basel) 2022; 8:309. [PMID: 35330310 PMCID: PMC8954760 DOI: 10.3390/jof8030309] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/03/2022] [Accepted: 03/07/2022] [Indexed: 02/01/2023] Open
Abstract
Susceptibility testing can yield variable results because it is method (commercial or reference), agent, and species dependent. Therefore, in order for results to be clinically relevant, MICs (minimal inhibitory concentrations) or MECs (minimal effective concentrations) should help in selecting the best treatment agent in the clinical setting. This is accomplished by categorical endpoints, ideally, breakpoints (BPs) and/or ECVs/ECOFFs (epidemiological cutoff values). BPs and ECVs are available by the reference methods (CLSI [Clinical and Laboratory Standards Institute] and EUCAST [European Committee on Antifungal Susceptibility Testing]) for a variety of species/agent combinations. The lack of clinical data precludes establishment of BPs for susceptibility testing by the commercial methods and ECVs have only been calculated for the Etest and SYO assays. The goal of this review is to summarize the variety of commercial methods for antifungal susceptibility testing and the potential value of Etest and SYO ECVs for detecting mutants/non-wild type (NWT) Candida isolates. Therefore, the literature search focused on publications where the commercial method, meaning MICs and ECVs, were reported for specific NWT isolates; genetic mutations have also been listed. For the Etest, the best performers recognizing the NWT were anidulafungin ECVs: 92% for the common species; 97% for C. glabrata and fluconazole ECVs, mostly for C. parapsilosis (45 NWT isolates). By the SYO, posaconazole ECVs recognized 93% of the C. albicans and 96% of the C. parapsilosis NWT isolates and micafungin ECVs 94% (mostly C. albicans and C. glabrata). Smaller sets, some with clinical data, were also listed. These are promising results for the use of both commercial methods to identify antifungal resistance (NWT isolates). However, ECVs for other species and methods need to be defined, including the C. neoformans complex and emerging species.
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Ivanov M, Ćirić A, Stojković D. Emerging Antifungal Targets and Strategies. Int J Mol Sci 2022; 23:2756. [PMID: 35269898 PMCID: PMC8911111 DOI: 10.3390/ijms23052756] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/24/2022] [Accepted: 02/27/2022] [Indexed: 12/14/2022] Open
Abstract
Despite abundant research in the field of antifungal drug discovery, fungal infections remain a significant healthcare burden. There is an emerging need for the development of novel antifungals since those currently available are limited and do not completely provide safe and secure protection. Since the current knowledge regarding the physiology of fungal cells and the infection mechanisms is greater than ever, we have the opportunity to use this for the development of novel generations of antifungals. In this review, we selected and summarized recent studies describing agents employing different antifungal mechanisms. These mechanisms include interference with fungal resistance, including impact on the efflux pumps and heat shock protein 90. Additionally, interference with virulence factors, such as biofilms and hyphae; the impact on fungal enzymes, metabolism, mitochondria, and cell wall; and antifungal vaccines are explored. The agents investigated belong to different classes of natural or synthetic molecules with significant attention given also to plant extracts. The efficacy of these antifungals has been studied mainly in vitro with some in vivo, and clinical studies are needed. Nevertheless, there is a large quantity of products employing novel antifungal mechanisms that can be further explored for the development of new generation of antifungals.
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Affiliation(s)
- Marija Ivanov
- Department of Plant Physiology, Institute for Biological Research “Siniša Stanković”—National Institute of Republic of Serbia, University of Belgrade, Bulevar despota Stefana 142, 11000 Belgrade, Serbia; (A.Ć.); (D.S.)
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Sun H, Cai X, Yan B, Bai H, Meng D, Mo X, He S, Su G, Jiang C. Multi-Omics Analysis of Lipid Metabolism for a Marine Probiotic Meyerozyma guilliermondii GXDK6 Under High NaCl Stress. Front Genet 2022; 12:798535. [PMID: 35096014 PMCID: PMC8792971 DOI: 10.3389/fgene.2021.798535] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 12/24/2021] [Indexed: 11/13/2022] Open
Abstract
Investigating microbial lipid regulation contributes to understanding the lipid-dependent signal transduction process of cells and helps to improve the sensitivity of microorganisms to environmental factors by interfering with lipid metabolism, thus beneficial for constructing advanced cell factories of novel molecular drugs. Integrated omics technology was used to systematically reveal the lipid metabolism mechanism of a marine Meyerozyma guilliermondii GXDK6 under high NaCl stress and test the sensitivity of GXDK6 to antibiotics when its lipid metabolism transformed. The omics data showed that when GXDK6 perceived 10% NaCl stress, the expression of AYR1 and NADPH-dependent 1-acyldihydroxyacetone phosphate reductase was inhibited, which weaken the budding and proliferation of cell membranes. This finding was further validated by decreased 64.39% of OD600 under 10% NaCl stress when compared with salt-free stress. In addition, salt stress promoted a large intracellular accumulation of glycerol, which was also verified by exogenous addition of glycerol. Moreover, NaCl stress remarkably inhibited the expression of drug target proteins (such as lanosterol 14-alpha demethylase), thereby increasing sensitivity to fluconazole. This study provided new insights into the molecular mechanism involved in the regulation of lipid metabolism in Meyerozyma guilliermondii strain and contributed to developing new methods to improve the effectiveness of killing fungi with lower antibiotics.
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Affiliation(s)
- Huijie Sun
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Research Center for Microbial and Enzyme Engineering Technology, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Xinghua Cai
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Research Center for Microbial and Enzyme Engineering Technology, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Bing Yan
- Guangxi Key Lab of Mangrove Conservation and Utilization, Guangxi Mangrove Research Center, Guangxi Academy of Sciences, Beihai, China
| | - Huashan Bai
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Research Center for Microbial and Enzyme Engineering Technology, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Duotao Meng
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Research Center for Microbial and Enzyme Engineering Technology, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Xueyan Mo
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Research Center for Microbial and Enzyme Engineering Technology, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Sheng He
- Guangxi Birth Defects Prevention and Control Institute, Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region, Nanning, China
| | - Guijiao Su
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Research Center for Microbial and Enzyme Engineering Technology, College of Life Science and Technology, Guangxi University, Nanning, China
| | - Chengjian Jiang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Research Center for Microbial and Enzyme Engineering Technology, College of Life Science and Technology, Guangxi University, Nanning, China.,Guangxi Key Lab of Mangrove Conservation and Utilization, Guangxi Mangrove Research Center, Guangxi Academy of Sciences, Beihai, China
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61
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K143R Amino Acid Substitution in 14-α-Demethylase (Erg11p) Changes Plasma Membrane and Cell Wall Structure of Candida albicans. Int J Mol Sci 2022; 23:ijms23031631. [PMID: 35163552 PMCID: PMC8836035 DOI: 10.3390/ijms23031631] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/27/2022] [Accepted: 01/28/2022] [Indexed: 02/07/2023] Open
Abstract
The opportunistic pathogen Candida albicans is responsible for life-threating infections in immunocompromised individuals. Azoles and polyenes are two of the most commonly used antifungals and target the ergosterol biosynthesis pathway or ergosterol itself. A limited number of clinically employed antifungals correspond to the development of resistance mechanisms. One resistance mechanism observed in clinical isolates of azole-resistant C. albicans is the introduction of point mutations in the ERG11 gene, which encodes a key enzyme (lanosterol 14-α-demethylase) on the ergosterol biosynthesis pathway. Here, we demonstrate that a point mutation K143R in ERG11 (C. albicans ERG11K143R/K143R) contributes not only to azole resistance, but causes increased gene expression. Overexpression of ERG11 results in increased ergosterol content and a significant reduction in plasma membrane fluidity. Simultaneously, the same point mutation caused cell wall remodeling. This could be facilitated by the unmasking of chitin and β-glucan on the fungal cell surface, which can lead to recognition of the highly immunogenic β-glucan, triggering a stronger immunological reaction. For the first time, we report that a frequently occurring azole-resistance strategy makes C. albicans less susceptible to azole treatment while, at the same time, affects its cell wall architecture, potentially leading to exposure of the pathogen to a more effective host immune response.
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62
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Zeng G, Li Z, Zhao Z. Metabolome analysis of key genes for synthesis and accumulation of triterpenoids in Wolfiporia cocos. Sci Rep 2022; 12:1574. [PMID: 35091582 PMCID: PMC8799705 DOI: 10.1038/s41598-022-05610-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 01/13/2022] [Indexed: 11/09/2022] Open
Abstract
Triterpenoid, the active ingredient in the dried sclerotia of Wolfiporia cocos, has a variety of pharmacological effects. The focus of this research was the cell engineered bacteria modified for triterpenoid biosynthesis, and we aimed to identify the key genes involved in triterpenoid biosynthesis and their roles. Two monospora strains, H and L, were selected from the sexually propagated progeny of W. coco strain 5.78, and their mycelia were cultured for 17, 34, and 51 days. Metabolite analysis showed that there were significantly more down-regulated metabolites of the two strains at three different culture periods than up-regulated metabolites. KEGG indicated that the differential metabolites were mainly concentrated in sterol biosynthesis and ABC transport. STEM analysis suggested that polysaccharide synthesis and accumulation might be greater in the L strain than the H strain. The correlation analysis of DEGs and differential metabolites between the two strain groups showed that erg11 and FDPS, which were closely positively correlated with differential metabolites associated with triterpenoids, were highly expressed in the L strain. This result suggested that the high expression of some genes in the L strain might shunt precursor substances of triterpenoids, which was the possible reason for the decrease in the synthesis and accumulation of triterpenoids.
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Affiliation(s)
| | - Zhong Li
- Guizhou University, Guiyang, 550025, China.
| | - Zhi Zhao
- Guizhou Key Laboratory of Propagation and Cultivation On Medicinal Plants, Guizhou University, Guiyang, 550025, China.
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63
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Chen Z, Luo T, Huang F, Yang F, Luo W, Chen G, Cao M, Wang F, Zhang J. Kangbainian Lotion Ameliorates Vulvovaginal Candidiasis in Mice by Inhibiting the Growth of Fluconazole-Resistant Candida albicans and the Dectin-1 Signaling Pathway Activation. Front Pharmacol 2022; 12:816290. [PMID: 35140608 PMCID: PMC8819624 DOI: 10.3389/fphar.2021.816290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 12/27/2021] [Indexed: 11/18/2022] Open
Abstract
Vulvovaginal candidiasis (VVC) is an infectious disease caused by Candida species, which affects millions of women worldwide every year. The resistance to available antifungal drugs for clinical treatment is a growing problem. The treatment of refractory VVC caused by azole-resistant Candida is still facing challenges. However, research on new antifungal drugs is progressing slowly. Although a lot of reports on new antifungal drugs, only three new antifungal drugs (Isavuconazole, ibrexafungerp, and rezafungin) and two new formulations of posaconazole were marketed over the last decade. Chinese botanical medicine has advantages in the treatment of drug-resistant VVC, such as outstanding curative effects and low adverse reactions, which can improve patients’ comfort and adherence to therapy. Kangbainian lotion (KBN), a Chinese botanical formulation, has achieved very good clinical effects in the treatment of VVC. In this study, we investigated the antifungal and anti-inflammatory effects of KBN at different doses in fluconazole-resistant (FLC-resistant) VVC model mice. We further studied the antifungal mechanism of KBN against FLC-resistant Candida albicans (C. albicans) and the anti-inflammatory mechanism correlated with the Dectin-1 signaling pathway. In vivo and in vitro results showed that KBN had strong antifungal and anti-inflammatory effects in FLC-resistant VVC, such as inhibiting the growth of C. albicans and vaginal inflammation. Further studies showed that KBN inhibited the biofilm and hypha formation, reduced adhesion, inhibited ergosterol synthesis and the expression of ergosterol synthesis-related genes ERG11, and reduced the expression of drug-resistant efflux pump genes MDR1 and CDR2 of FLC-resistant C. albicans in vitro. In addition, in vivo results showed that KBN reduced the expression of inflammatory factor proteins TNF-α, IL-1β, and IL-6 in vaginal tissues, and inhibited the expression of proteins related to the Dectin-1 signaling pathway. In conclusion, our study revealed that KBN could ameliorate vaginal inflammation in VVC mice caused by FLC-resistance C. albicans. This effect may be related to inhibiting the growth of FLC-resistance C. albicans and Dectin-1 signaling pathway activation.
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Affiliation(s)
- Zewei Chen
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Tengshuo Luo
- School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, China
| | - Fengke Huang
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Fuzhen Yang
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Wenting Luo
- The Second Clinical College, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Guanfeng Chen
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Mengfei Cao
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Fengyun Wang
- School of Chinese Materia Medica, Guangdong Pharmaceutical University, Guangzhou, China
- *Correspondence: Jun Zhang, ; Fengyun Wang,
| | - Jun Zhang
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, China
- *Correspondence: Jun Zhang, ; Fengyun Wang,
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64
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Azole-resistant alleles of
ERG11
in
Candida glabrata
trigger activation of the Pdr1 and Upc2A transcription factors. Antimicrob Agents Chemother 2022; 66:e0209821. [DOI: 10.1128/aac.02098-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
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
Candida
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
ERG11
gene. Here, we generated
C. glabrata
ERG11
mutations that were analogous to azole resistance alleles from
C. albicans
ERG11
. 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
ERG11
imposed a fitness cost that was not observed with hyperactive
PDR1
alleles. Crucially, the presence of the DM
ERG11
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
ERG11
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
.
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65
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Murphy SE, Bicanic T. Drug Resistance and Novel Therapeutic Approaches in Invasive Candidiasis. Front Cell Infect Microbiol 2022; 11:759408. [PMID: 34970504 PMCID: PMC8713075 DOI: 10.3389/fcimb.2021.759408] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 11/08/2021] [Indexed: 12/12/2022] Open
Abstract
Candida species are the leading cause of invasive fungal infections worldwide and are associated with acute mortality rates of ~50%. Mortality rates are further augmented in the context of host immunosuppression and infection with drug-resistant Candida species. In this review, we outline antifungal drugs already in clinical use for invasive candidiasis and candidaemia, their targets and mechanisms of resistance in clinically relevant Candida species, encompassing not only classical resistance, but also heteroresistance and tolerance. We describe novel antifungal agents and targets in pre-clinical and clinical development, including their spectrum of activity, antifungal target, clinical trial data and potential in treatment of drug-resistant Candida. Lastly, we discuss the use of combination therapy between conventional and repurposed agents as a potential strategy to combat the threat of emerging resistance in Candida.
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Affiliation(s)
- Sarah E Murphy
- Institute of Infection & Immunity, St George's University of London, London, United Kingdom
| | - Tihana Bicanic
- Institute of Infection & Immunity, St George's University of London, London, United Kingdom.,Clinical Academic Group in Infection and Immunity, St. George's University Hospital National Health Service (NHS) Foundation Trust, London, United Kingdom
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66
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Rogers TR, Verweij PE, Castanheira M, Dannaoui E, White PL, Arendrup MC. OUP accepted manuscript. J Antimicrob Chemother 2022; 77:2053-2073. [PMID: 35703391 PMCID: PMC9333407 DOI: 10.1093/jac/dkac161] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The increasing incidence and changing epidemiology of invasive fungal infections continue to present many challenges to their effective management. The repertoire of antifungal drugs available for treatment is still limited although there are new antifungals on the horizon. Successful treatment of invasive mycoses is dependent on a mix of pathogen-, host- and antifungal drug-related factors. Laboratories need to be adept at detection of fungal pathogens in clinical samples in order to effectively guide treatment by identifying isolates with acquired drug resistance. While there are international guidelines on how to conduct in vitro antifungal susceptibility testing, these are not performed as widely as for bacterial pathogens. Furthermore, fungi generally are recovered in cultures more slowly than bacteria, and often cannot be cultured in the laboratory. Therefore, non-culture-based methods, including molecular tests, to detect fungi in clinical specimens are increasingly important in patient management and are becoming more reliable as technology improves. Molecular methods can also be used for detection of target gene mutations or other mechanisms that predict antifungal drug resistance. This review addresses acquired antifungal drug resistance in the principal human fungal pathogens and describes known resistance mechanisms and what in-house and commercial tools are available for their detection. It is emphasized that this approach should be complementary to culture-based susceptibility testing, given the range of mutations, resistance mechanisms and target genes that may be present in clinical isolates, but may not be included in current molecular assays.
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Affiliation(s)
| | | | | | | | | | - Maiken Cavling Arendrup
- Unit of Mycology, Statens Serum Institut, Copenhagen, Denmark
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
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67
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Rybak JM, Sharma C, Doorley LA, Barker KS, Palmer GE, Rogers PD. Delineation of the Direct Contribution of Candida auris ERG11 Mutations to Clinical Triazole Resistance. Microbiol Spectr 2021; 9:e0158521. [PMID: 34878305 PMCID: PMC8653815 DOI: 10.1128/spectrum.01585-21] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 10/28/2021] [Indexed: 11/27/2022] Open
Abstract
Resistance to fluconazole is one of clinical characteristics most frequently challenging the treatment of invasive Candida auris infections, and is observed among >90% of all characterized clinical isolates. In this work, the native C. auris ERG11 allele in a previously characterized fluconazole-susceptible clinical isolate was replaced with the ERG11 alleles from three highly fluconazole-resistant clinical isolates (MIC ≥256 mg/L), encoding the amino acid substitutions VF125AL, Y132F, and K143R, using Cas9-ribonucleoprotein (RNP) mediated transformation system. Reciprocally, the ERG11WT allele from the same fluconazole-susceptible clinical isolate, lacking any resistance-associated mutation, was introduced into a previously characterized fluconazole-resistant clinical isolate, replacing the native ERG11K143R allele, using the same methods. The resulting collection of strains was subjected to comprehensive triazole susceptibility testing, and the direct impact each of these clinically-derived ERG11 mutations on triazole MIC was determined. Introduction of each of the three mutant ERG11 alleles was observed to increase fluconazole and voriconazole MIC by 8- to 16-fold. The MIC for the other clinically available triazoles were not significantly impacted by any ERG11 mutation. In the fluconazole-resistant clinical isolate background, correction of the K143R encoding mutation led to a similar 16-fold decrease in fluconazole MIC, and 8-fold decrease in voriconazole MIC, while the MIC of other triazoles were minimally changed. Taken together, these findings demonstrate that mutations in C. auris ERG11 significantly contribute to fluconazole and voriconazole resistance, but alone cannot explain the substantially elevated MIC observed among clinical isolates of C. auris. IMPORTANCE Candida auris is an emerging multidrug-resistant and health care-associated pathogen of urgent clinical concern. The triazoles are the most widely prescribed antifungal agents worldwide and are commonly utilized for the treatment of invasive Candida infections. Greater than 90% of all C. auris clinical isolates are observed to be resistant to fluconazole, and nearly all fluconazole-resistant isolates of C. auris are found to have one of three mutations (encoding VF125AL, Y132F, or K143R) in the gene encoding the target of the triazoles, ERG11. However, the direct contribution of these mutations in ERG11 to fluconazole resistance and the impact these mutations may have the susceptibility of the other triazoles remains unknown. The present study seeks to address this knowledge gap and potentially inform the future application the triazole antifungals for the treatment of infections caused by C. auris.
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Affiliation(s)
- Jeffrey M. Rybak
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Cheshta Sharma
- Department of Clinical Pharmacy and Translational Science, University of Tennessee College of Pharmacy, Memphis, Tennessee, USA
| | - Laura A. Doorley
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Katherine S. Barker
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Glen E. Palmer
- Department of Clinical Pharmacy and Translational Science, University of Tennessee College of Pharmacy, Memphis, Tennessee, USA
| | - P. David Rogers
- Department of Pharmacy and Pharmaceutical Sciences, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
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68
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Rashidi N, Rezaie S, Hashemi SJ, Habibi A, Baghersad MH, Daie R, Khodavaisy S, Bakhshi H, Salimi A, Getso ME, Rafat Z. Synthesis, Cytotoxicity Evaluation, and Antifungal Activity of Novel Nitroglycerin Derivatives against Clinical Candida albicans Isolates. IRANIAN JOURNAL OF PUBLIC HEALTH 2021; 50:1872-1881. [PMID: 34722383 PMCID: PMC8542828 DOI: 10.18502/ijph.v50i9.7060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 06/11/2020] [Indexed: 11/24/2022]
Abstract
Background Candida albicans remains the main cause of candidiasis in most clinical settings. Available drugs for candidiasis treatment have many side effects. In this work, novel nitroglycerin derivatives were synthesized and their cytotoxic and antifungal effects evaluated against fluconazole susceptible and resistant clinical C. albicans isolates. Methods This experimental study was performed in Tehran University of Medical Sciences and Baqiatallah University of Medical Sciences, Tehran, Iran between Feb to Dec 2019. The in vitro activities of two novel nitroglycerin derivatives (1b and 2b) against 25 clinical fluconazole-susceptible and resistant C. albicans isolates and four standard C. albicans strains were determined according to CLSI reference M27-A3 documents. The cytotoxicity of chemical compounds was investigated near the SNL76/7 cells by colorimetric assay. Real-time PCRs were performed to evaluate the alterations in the regulation of ERG11 and CDR1 genes under nitroglycerin derivatives-treated and untreated conditions. Results The derivatives 1b and 2b exhibited potent antifungal activity against C. albicans isolates; MICs and MFCs varied from 18 μg/ml to 72 μg/ml and 36 μg/ml to 144 μg/ml, respectively. The cell viability evaluation demonstrated that both chemical compounds are safe within 24h. The nitroglycerin derivatives were able to reduce the transcription level of CDR1 and ERG11 genes in all susceptible and resistant C. albicans isolates. Conclusion Considering the potential and efficacy of these compounds against clinical C. albicans isolates, the complementary in vivo and clinical trials should be investigated.
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Affiliation(s)
- Niloofar Rashidi
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Sassan Rezaie
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Sayed Jamal Hashemi
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Aziziollah Habibi
- Department of Chemistry, Faculty of Chemistry, Kharazmi University, Tehran, Iran
| | - Mohammad Hadi Baghersad
- Applied Biotechnology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Roshanak Daie
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Sadegh Khodavaisy
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Heidar Bakhshi
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Salimi
- Nanobiotechnology Reserch Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Mohammad Ebraim Getso
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Zahra Rafat
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
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69
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Structural Insights into the Azole Resistance of the Candida albicans Darlington Strain Using Saccharomyces cerevisiae Lanosterol 14α-Demethylase as a Surrogate. J Fungi (Basel) 2021; 7:jof7110897. [PMID: 34829185 PMCID: PMC8621857 DOI: 10.3390/jof7110897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 10/15/2021] [Accepted: 10/19/2021] [Indexed: 11/17/2022] Open
Abstract
Target-based azole resistance in Candida albicans involves overexpression of the ERG11 gene encoding lanosterol 14α-demethylase (LDM), and/or the presence of single or multiple mutations in this enzyme. Overexpression of Candida albicans LDM (CaLDM) Y132H I471T by the Darlington strain strongly increased resistance to the short-tailed azoles fluconazole and voriconazole, and weakly increased resistance to the longer-tailed azoles VT-1161, itraconazole and posaconazole. We have used, as surrogates, structurally aligned mutations in recombinant hexahistidine-tagged full-length Saccharomyces cerevisiae LDM6×His (ScLDM6×His) to elucidate how differential susceptibility to azole drugs is conferred by LDM of the C. albicans Darlington strain. The mutations Y140H and I471T were introduced, either alone or in combination, into ScLDM6×His via overexpression of the recombinant enzyme from the PDR5 locus of an azole hypersensitive strain of S. cerevisiae. Phenotypes and high-resolution X-ray crystal structures were determined for the surrogate enzymes in complex with representative short-tailed (voriconazole) and long-tailed (itraconazole) triazoles. The preferential high-level resistance to short-tailed azoles conferred by the ScLDM Y140H I471T mutant required both mutations, despite the I471T mutation conferring only a slight increase in resistance. Crystal structures did not detect changes in the position/tilt of the heme co-factor of wild-type ScLDM, I471T and Y140H single mutants, or the Y140H I471T double-mutant. The mutant threonine sidechain in the Darlington strain CaLDM perturbs the environment of the neighboring C-helix, affects the electronic environment of the heme, and may, via differences in closure of the neck of the substrate entry channel, increase preferential competition between lanosterol and short-tailed azole drugs.
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70
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Impact of Erg11 amino acid substitutions identified in Candida auris clade III isolates on triazole drug susceptibility. Antimicrob Agents Chemother 2021; 66:e0162421. [PMID: 34633842 DOI: 10.1128/aac.01624-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
ERG11 sequencing of 28 Candida auris clade III isolates revealed the presence of concomitant V125A and F126L substitutions. Heterologous expression of Erg11-V125A/F126L in Saccharomyces cerevisiae led to reduced fluconazole and voriconazole susceptibilities. Generation of single substitution gene variants through site-directed mutagenesis uncovered that F126L primarily contributes to the elevated triazole MICs. A similar, yet diminished pattern of reduced susceptibility was observed with long-tailed triazoles posaconazole and itraconazole for V125A/F126L, F126L, Y132F, and K143R alleles.
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71
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Yang Q, He B, Chen C, Wang H, Li W, Xue X, Qiu T, Hao X, Lv F, Wang S. A Rapid, Visible, and Highly Sensitive Method for Recognizing and Distinguishing Invasive Fungal Infections via CCP-FRET Technology. ACS Infect Dis 2021; 7:2816-2825. [PMID: 34585580 DOI: 10.1021/acsinfecdis.1c00393] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Invasive fungal infection (IFI) is one of the leading causes of death in the intensive care unit (ICU) due to its high morbidity and mortality among immunocompromised patients. Early diagnosis of IFI is typically infeasible because of the lack of clinical signs and symptoms. By virtue of the cationic conjugated polymer-based fluorescence resonance energy transfer (CCP-FRET) technology, we develop a rapid, visible, simple, and sensitive method for simultaneous detection and discrimination of three types of pathogens, including Candida albicans (C. albicans), Klebsiella pneumoniae (K. pneumoniae), and Cryptococcus neoformans (C. neoformans). The CCP-FRET system contains a CCP fluorescent probe and pathogen-specific DNA labeled with fluorescent dyes. These two components spontaneously self-assemble into the complex under electrostatic attraction, resulting in an efficient FRET from CCP to fluorescent dyes when irradiated with a 380 nm ultraviolet (UV) light. The CCP-FRET method can specifically identify the DNA molecules that are extracted from culture pathogen strains or blood samples via PCR and single base extension (SBE) reactions, without any cross-reactions on the DNA of nonspecific strains. In particular, the sensitivity of this method is down to 0.03125 ng, which is ten times higher than that of real-time PCR. We further evaluate its detection efficiency by testing 15 blood samples from neonatal patients who suffer from pathogen infections, in which some of them have undergone antipathogen treatments. Using the CCP-FRET method, 33.3% (5/15) of samples tested positive for C. albicans and/or K. pneumoniae infections, whereas no pathogen DNAs are recognized with real-time PCR, despite using the same primers. Interestingly, the CCP-FRET method can output unique fluorescent color as well as RGB patterns to different types of pathogen infections, by which the infection type can be conveniently determined. Collectively, the CCP-FRET method is a sensitive and reliable detection platform for rapid identification of fungal and bacterial multiple infections, holding great promise for uses in clinical testing.
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Affiliation(s)
- Qiong Yang
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Binghong He
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Chong Chen
- Department of Pediatrics, The Seventh Medical Center of the Chinese People’s Liberation Army General Hospital, Beijing 100700, China
| | - Haitao Wang
- Department of Hematology and Oncology, The Fourth Medical Center of the Chinese People’s Liberation Army General Hospital, Beijing 100010, China
| | - Wanjie Li
- College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Xiuhua Xue
- College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Tian Qiu
- Department of Pathology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100029, China
| | - Xiaoran Hao
- College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Fengting Lv
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Shu Wang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
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72
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Hassanpour P, Hamishehkar H, Bahari Baroughi B, Baradaran B, Sandoghchian Shotorbani S, Mohammadi M, Shomali N, Aghebati-Maleki L, Nami S. Antifungal Effects of Voriconazole-Loaded Nano-Liposome on Fluconazole -Resistant Clinical Isolates of Candida albicans, Biological Activity and ERG11, CDR1, and CDR2 Gene Expression. Assay Drug Dev Technol 2021; 19:453-462. [PMID: 34435891 DOI: 10.1089/adt.2020.1057] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
This study aimed to assess the effect of voriconazole (VCZ)-loaded nano-liposomes on biological activity and expression of ERG11, CDR1, and CDR2 genes in fluconazole (FCZ)-resistant Candida albicans. In this study, 5 resistant isolates of C. albicans and 3 susceptible clinical isolates to FCZ were scrutinized from 60 patients suspected of candidiasis. The liposomal formulation of VCZ was produced. After that, the minimum biofilm inhibitory concentration (MBIC) testing was performed and the percentage of growth inhibition was determined. Finally, ERG11, CDR1, and CDR2 mRNA levels were amplified by the quantitative reverse transcription PCR (qRT-PCR) instrument. The obtained results unveiled that VCZ-loaded nano-liposome reduction of minimum inhibitory concentration in C. albicans isolates was remarkable. The results of the MBIC in the most optimum inhibitory concentration of VCZ-loaded nano-liposome were determined to be 4.54 and 4.88 μg/mL for susceptible isolate and resistant isolate, respectively. The ERG11 gene expression in FCZ-resistant C. albicans strains in VCZ-treated, liposomal formulation of VCZ-treated, and nontreated specimens stood at 91%, 63%, and 100%, respectively. Expression levels of CDR1 genes in FCZ-resistant C. albicans were shown to be 91%, 88%, and 100%, respectively. Concerning CDR2 genes, this rate varied to 91%, 78%, and 100% in FCZ resistant, respectively. What our study unveiled was that the use of liposomal VCZ formulation could further reduce the expression of azole-resistant genes compared to VCZ itself. In addition, thanks to more efficacious penetration of the liposomal form, the rate of growth inhibition was considerably higher.
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Affiliation(s)
- Parviz Hassanpour
- Department of Parasitology and Mycology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Hamed Hamishehkar
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Behzad Baradaran
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Maryam Mohammadi
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.,Biotechnology Research Center and Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Navid Shomali
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Leili Aghebati-Maleki
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.,Department of Immunology, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Sanam Nami
- Department of Parasitology and Mycology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.,Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
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73
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Etest ECVs/ECOFFs for detection of resistance in prevalent and three non-prevalent Candida spp. to triazoles and amphotericin B and Aspergillus spp. to caspofungin: Further assessment of modal variability. Antimicrob Agents Chemother 2021; 65:e0109321. [PMID: 34370582 DOI: 10.1128/aac.01093-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Susceptibility testing is an important tool in the clinical setting; its utility is based on the availability of categorical endpoints, breakpoints (BPs) or epidemiological cutoff values (ECVs/ECOFFs). CLSI and EUCAST have developed antifungal susceptibility testing, BPs and ECVs for some fungal species. Although the Concentration Gradient Strip BioMerieux Etest is useful for routine testing in the clinical laboratory, ECVs are not available for all agent/species; the lack of clinical data precludes development of BPs. We re-evaluated and consolidated Etest data points from three previous studies, and included new data. We defined ECOFFinder Etest ECVs for three sets of species/agent combinations: fluconazole, posaconazole and voriconazole and 8 Candida spp.; amphotericin B and 3 non-prevalent Candida spp.; and caspofungin and 5 Aspergillus spp. The total of Etest MICs from 23 laboratories (Europe, the Americas, South Africa) included (antifungal agent/dependent): 17,242 Candida albicans, 244 C. dubliniensis, 5,129 C. glabrata species complex (SC), 275 C. guilliermondii (Meyerozyma guilliermondii), 1,133 C. krusei (Pichia kudriavzevii), 933 C. kefyr (Kluyveromyces marxianus), 519 C. lusitaniae (Clavispora lusitaniae), 2,947 C. parapsilosis SC, 2,214 C. tropicalis, 3,212 Aspergillus fumigatus, 232 A. flavus, 181 A. niger, and 267 A. terreus SC isolates. Triazole MICs for 66 confirmed non-wild-type (non-WT) Candida isolates were available (ERG11 point mutations). Distributions fulfilling CLSI ECV criteria were pooled and ECOFFinder Etest ECVs were established for triazoles (9 Candida spp.); amphotericin B (3 less-prevalent Candida spp.) and caspofungin (4 Aspergillus spp.). Etest fluconazole ECVs could be good detectors of Candida non-WT isolates (59/61 Non-WT: 4 of 6 species).
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74
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Antifungal Drug Susceptibility and Genetic Characterization of Fungi Recovered from COVID-19 Patients. J Fungi (Basel) 2021; 7:jof7070552. [PMID: 34356931 PMCID: PMC8306261 DOI: 10.3390/jof7070552] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 07/09/2021] [Accepted: 07/10/2021] [Indexed: 01/08/2023] Open
Abstract
Fungal infections are common complications of respiratory viral infections and are associated with the increased need for intensive care and elevated mortality. Data regarding microbiological and molecular characteristics of such infections in COVID-19 patients are scarce. Here, we performed a comprehensive analysis, including species identification, antifungal susceptibility testing, molecular resistance determinants analysis, typing, and retrospective clinical data review, of fungal isolates recovered from 19 COVID-19 patients, who were hospitalized at the Hackensack University Medical Center (HUMC) in Hackensack, New Jersey, USA, in the initial phase of the pandemic from April–May 2020. In total, 17 Candida albicans, two C. parapsilosis, and two Aspergillus fumigatus were analyzed. All Candida spp. isolates were susceptible to micafungin and azole drugs (fluconazole, voriconazole, posaconazole, itraconazole, isavuconazole). A. fumigatus isolates were susceptible to micafungin and all triazole drugs except fluconazole (intrinsic resistance). Multilocus sequence typing (MLST) of C. albicans isolates revealed 15 different sequence types (STs), which clustered below the clade-defining limit of p-distance < 0.04. Pulsed-field gel electrophoresis (PFGE) karyotyping revealed no chromosomal rearrangements in these isolates. A. fumigatus isolates were of different, non-related genotypes. We speculate that virus- and drug-induced immunosuppression (94.7% of the patients received corticosteroids), together with prolonged hospital stay (median duration of 29 days) and mechanical ventilation (median duration of 24 days) likely increased the susceptibility to secondary respiratory and bloodstream infections in the studied patient population. The presence of fungi in blood or respiratory tract fluid was a prognosticator for poor clinical outcome, which presented as an 89.5% 30-day mortality in our patient cohort.
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75
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Huët MAL, Muzahid NH, Lee CZ, Goh CBS, Dwiyanto J, Rahman S, Tan JBL. Molecular typing of multi-drug resistant Candida albicans isolated from the Segamat community, Malaysia. Braz J Microbiol 2021; 52:2351-2356. [PMID: 34235705 DOI: 10.1007/s42770-021-00558-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 06/28/2021] [Indexed: 10/20/2022] Open
Abstract
In the past decade, researchers have focused on the emergence of drug resistance in fungal pathogens such as Candida albicans, also considered as pathobionts that occur harmlessly in the human body but could potentially be triggered to cause diseases. The increasing rate of antifungal resistance in commensal gut fungi is alarming and should be further investigated. Here, we report seven novel MLST (Multi Locus Sequence Typing) genotypes of multi-drug resistant C. albicans isolates obtained from participants of a community study in Segamat, a district in the state of Johor, Malaysia. A total of eight C. albicans were isolated from four individuals, which were found to express high resistance against fluconazole, itraconazole, voriconazole and 5-fluorocytosine antifungals. MLST was performed to assess the clonal relatedness of these drug resistant isolates among themselves and against other strains isolated from other geographical regions. The novel MLST C. albicans sequence types suggest significant genetic changes compared to previous genotypes.
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Affiliation(s)
- Marie Andrea Laetitia Huët
- School of Science, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, 47500, Subang Jaya, Selangor, Malaysia
| | - Nazmul Hasan Muzahid
- School of Science, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, 47500, Subang Jaya, Selangor, Malaysia
| | - Chuen Zhang Lee
- School of Science, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, 47500, Subang Jaya, Selangor, Malaysia
| | - Calvin Bok Sun Goh
- School of Science, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, 47500, Subang Jaya, Selangor, Malaysia
| | - Jacky Dwiyanto
- School of Science, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, 47500, Subang Jaya, Selangor, Malaysia
| | - Sadequr Rahman
- School of Science, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, 47500, Subang Jaya, Selangor, Malaysia.,Tropical Medicine & Biology Multidisciplinary Platform, Monash University Malaysia, Subang Jaya, Malaysia
| | - Joash Ban Lee Tan
- School of Science, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, 47500, Subang Jaya, Selangor, Malaysia.
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76
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Sitterlé E, Coste AT, Obadia T, Maufrais C, Chauvel M, Sertour N, Sanglard D, Puel A, D'Enfert C, Bougnoux ME. Large-scale genome mining allows identification of neutral polymorphisms and novel resistance mutations in genes involved in Candida albicans resistance to azoles and echinocandins. J Antimicrob Chemother 2021; 75:835-848. [PMID: 31923309 DOI: 10.1093/jac/dkz537] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 11/22/2019] [Accepted: 12/01/2019] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND The genome of Candida albicans displays significant polymorphism. Point mutations in genes involved in resistance to antifungals may either confer phenotypic resistance or be devoid of phenotypic consequences. OBJECTIVES To catalogue polymorphisms in azole and echinocandin resistance genes occurring in susceptible strains in order to rapidly pinpoint relevant mutations in resistant strains. METHODS Genome sequences from 151 unrelated C. albicans strains susceptible to fluconazole and caspofungin were used to create a catalogue of non-synonymous polymorphisms in genes involved in resistance to azoles (ERG11, TAC1, MRR1 and UPC2) or echinocandins (FKS1). The potential of this catalogue to reveal putative resistance mutations was tested in 10 azole-resistant isolates, including 1 intermediate to caspofungin. Selected mutations were analysed by mutagenesis experiments or mutational prediction effect. RESULTS In the susceptible strains, we identified 126 amino acid substitutions constituting the catalogue of phenotypically neutral polymorphisms. By excluding these neutral substitutions, we identified 22 additional substitutions in the 10 resistant strains. Among these substitutions, 10 had already been associated with resistance. The remaining 12 were in Tac1p (n = 6), Upc2p (n = 2) and Erg11p (n = 4). Four out of the six homozygous substitutions in Tac1p (H263Y, A790V, H839Y and P971S) conferred increases in azole MICs, while no effects were observed for those in Upc2p. Additionally, two homozygous substitutions (Y64H and P236S) had a predicted conformation effect on Erg11p. CONCLUSIONS By establishing a catalogue of neutral polymorphisms occurring in genes involved in resistance to antifungal drugs, we provide a useful resource for rapid identification of mutations possibly responsible for phenotypic resistance in C. albicans.
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Affiliation(s)
- Emilie Sitterlé
- Unité Biologie et Pathogénicité Fongiques, Département de Mycologie, Institut Pasteur, USC2019 INRA, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, Paris, France.,Unité de Parasitologie-Mycologie, Service de Microbiologie clinique, Hôpital Necker-Enfants-Malades, Assistance Publique des Hôpitaux de Paris (APHP), Paris, France
| | - Alix T Coste
- Institut de Microbiologie, Université de Lausanne et Centre Hospitalo-Universitaire, Lausanne, Switzerland
| | - Thomas Obadia
- Hub de Bioinformatique et Biostatistique, Département Biologie Computationnelle, Institut Pasteur, USR 3756 CNRS, Paris, France.,Unité Malaria: parasites et hôtes, Département Parasites et Insectes Vecteurs, Institut Pasteur, Paris, France
| | - Corinne Maufrais
- Hub de Bioinformatique et Biostatistique, Département Biologie Computationnelle, Institut Pasteur, USR 3756 CNRS, Paris, France
| | - Murielle Chauvel
- Unité Biologie et Pathogénicité Fongiques, Département de Mycologie, Institut Pasteur, USC2019 INRA, Paris, France
| | - Natacha Sertour
- Unité Biologie et Pathogénicité Fongiques, Département de Mycologie, Institut Pasteur, USC2019 INRA, Paris, France
| | - Dominique Sanglard
- Institut de Microbiologie, Université de Lausanne et Centre Hospitalo-Universitaire, Lausanne, Switzerland
| | - Anne Puel
- Laboratoire de génétique humaine des maladies infectieuses, Necker, INSERM U1163, Paris, France.,Université Paris Descartes, Institut Imagine, Paris, France
| | - Christophe D'Enfert
- Unité Biologie et Pathogénicité Fongiques, Département de Mycologie, Institut Pasteur, USC2019 INRA, Paris, France
| | - Marie-Elisabeth Bougnoux
- Unité Biologie et Pathogénicité Fongiques, Département de Mycologie, Institut Pasteur, USC2019 INRA, Paris, France.,Unité de Parasitologie-Mycologie, Service de Microbiologie clinique, Hôpital Necker-Enfants-Malades, Assistance Publique des Hôpitaux de Paris (APHP), Paris, France.,Université de Paris, Paris, France
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77
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Uddin W, Dhabalia D, Prakash SMU, Kabir MA. Systematic truncations of chromosome 4 and their responses to antifungals in Candida albicans. J Genet Eng Biotechnol 2021; 19:92. [PMID: 34152516 PMCID: PMC8217416 DOI: 10.1186/s43141-021-00197-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 06/10/2021] [Indexed: 01/08/2023]
Abstract
BACKGROUND Candida albicans is an opportunistic human fungal pathogen responsible for superficial and systemic life-threatening infections. Treating these infections is challenging as many clinical isolates show increased drug resistance to antifungals. Chromosome (Chr) 4 monosomy was implicated in a fluconazole-resistant mutant. However, exposure to fluconazole adversely affects Candida cells and can generate numerous mutations. Hence, the present study aimed to truncate Chr4 and challenge the generated Candida strains to antifungals and evaluate their role in drug response. RESULTS Herein, Chr4 was truncated in C. albicans using the telomere-mediated chromosomal truncation method. The resulting eight Candida strains carrying one truncated homolog of Chr4 were tested for response to multiple antifungals. The minimal inhibitory concentration (MIC) for these strains was determined against three classes of antifungals. The MIC values against fluconazole, amphotericin B, and caspofungin were closer to that of the wild type strain. Microdilution assay against fluconazole showed that the mutants and wild type strains had similar sensitivity to fluconazole. The disc diffusion assay against five azoles and two polyenes revealed that the zones of inhibition for all the eight strains were similar to those of the wild type. Thus, none of the generated strains showed any significant resistance to the tested antifungals. However, spot assay exhibited a reasonably high tolerance of a few generated strains with increasing concentrations of fluconazole. CONCLUSION This analysis suggested that Chr4 aneuploidy might not underlie drug resistance but rather drug tolerance in Candida albicans.
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Affiliation(s)
- Wasim Uddin
- Molecular Genetics Laboratory, School of Biotechnology, National Institute of Technology Calicut, Calicut, Kerala, 673601, India
| | - Darshan Dhabalia
- Molecular Genetics Laboratory, School of Biotechnology, National Institute of Technology Calicut, Calicut, Kerala, 673601, India
| | - S M Udaya Prakash
- Molecular Genetics Laboratory, School of Biotechnology, National Institute of Technology Calicut, Calicut, Kerala, 673601, India
| | - M Anaul Kabir
- Molecular Genetics Laboratory, School of Biotechnology, National Institute of Technology Calicut, Calicut, Kerala, 673601, India.
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78
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Nishimoto AT, Sharma C, Rogers PD. Molecular and genetic basis of azole antifungal resistance in the opportunistic pathogenic fungus Candida albicans. J Antimicrob Chemother 2021; 75:257-270. [PMID: 31603213 DOI: 10.1093/jac/dkz400] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Candida albicans is an opportunistic yeast and the major human fungal pathogen in the USA, as well as in many other regions of the world. Infections with C. albicans can range from superficial mucosal and dermatological infections to life-threatening infections of the bloodstream and vital organs. The azole antifungals remain an important mainstay treatment of candidiasis and therefore the investigation and understanding of the evolution, frequency and mechanisms of azole resistance are vital to improving treatment strategies against this organism. Here the organism C. albicans and the genetic changes and molecular bases underlying the currently known resistance mechanisms to the azole antifungal class are reviewed, including up-regulated expression of efflux pumps, changes in the expression and amino acid composition of the azole target Erg11 and alterations to the organism's typical sterol biosynthesis pathways. Additionally, we update what is known about activating mutations in the zinc cluster transcription factor (ZCF) genes regulating many of these resistance mechanisms and review azole import as a potential contributor to azole resistance. Lastly, investigations of azole tolerance in C. albicans and its implicated clinical significance are reviewed.
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Affiliation(s)
- Andrew T Nishimoto
- Department of Clinical Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Cheshta Sharma
- Department of Clinical Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
| | - P David Rogers
- Department of Clinical Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
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79
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Abstract
Over the past 15 years, there has been an increase in the development and utilization of newer antifungal agents. The ideal antifungal, however, in regard to spectrum of activity, pharmacokinetic/pharmacodynamic properties, development of resistance, safety, and drug interaction profile remains elusive. This article reviews pharmacologic aspects of Food and Drug Administration-approved polyenes, flucytosine, azoles, and echinocandins as well as promising pipeline antifungal agents. Unique properties of these newer agents are highlighted. The clinical role of established and investigational antifungal agents as treatment and/or prevention of invasive fungal infections is discussed.
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Affiliation(s)
- Melissa D Johnson
- Duke University Medical Center, Box 102359 DUMC, Durham NC 27710, USA.
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80
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Abstract
Pathogenic fungi have several mechanisms of resistance to antifungal drugs, driven by the genetic plasticity and versatility of their homeostatic responses to stressful environmental cues. We critically review the molecular mechanisms of resistance and cellular adaptations of pathogenic fungi in response to antifungals and discuss the factors contributing to such resistance. We offer suggestions for the translational and clinical research agenda of this rapidly evolving and medically important field. A better understanding of antifungal resistance should assist in developing better detection tools and inform optimal strategies for preventing and treating refractory mycoses in the future.
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Affiliation(s)
- Ronen Ben-Ami
- Infectious Diseases Department, Sackler School of Medicine, Tel Aviv University, Tel Aviv Sourasky Medical Center, 6 Weizmann, Tel Aviv 64239, Israel
| | - Dimitrios P Kontoyiannis
- Infectious Diseases, University of Texas M D Anderson Cancer Center, 1515 Holcombe, Houston, TX 77030, USA.
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81
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Chew KL, Octavia S, Jureen R, Lin RTP, Teo JWP. Targeted amplification and MinION nanopore sequencing of key azole and echinocandin resistance determinants of clinically relevant Candida spp. from blood culture bottles. Lett Appl Microbiol 2021; 73:286-293. [PMID: 34060660 DOI: 10.1111/lam.13516] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/29/2021] [Accepted: 05/21/2021] [Indexed: 12/19/2022]
Abstract
The objective of the study was to evaluate the use of targeted multiplex Nanopore MinION amplicon re-sequencing of key Candida spp. from blood culture bottles to identify azole and echinocandin resistance associated SNPs. Targeted PCR amplification of azole (ERG11 and ERG3) and echinocandin (FKS) resistance-associated loci was performed on positive blood culture media. Sequencing was performed using MinION nanopore device with R9.4.1 Flow Cells. Twenty-eight spiked blood cultures (ATCC strains and clinical isolates) and 12 prospectively collected positive blood cultures with candidaemia were included. Isolate species included Candida albicans, Candida glabrata, Candida krusei, Candida parapsilosis, Candida tropicalis and Candida auris. SNPs that were identified on ERG and FKS genes using Snippy tool and CLC Genomic Workbench were correlated with phenotypic testing by broth microdilution (YeastOne™ Sensititre). Illumina whole-genome-sequencing and Sanger-sequencing were also performed as confirmatory testing of the mutations identified from nanopore sequencing data. There was a perfect agreement of the resistance-associated mutations detected by MinION-nanopore-sequencing compared to phenotypic testing for acquired resistance (16 with azole resistance; 3 with echinocandin resistance), and perfect concordance of the nanopore sequence mutations to Illumina and Sanger data. Mutations with no known association with phenotypic drug resistance and novel mutations were also detected.
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Affiliation(s)
- K L Chew
- Department of Laboratory Medicine, National University Hospital, Singapore
| | - S Octavia
- National Public Health Laboratory, National Centre for Infectious Diseases, Singapore
| | - R Jureen
- Department of Laboratory Medicine, National University Hospital, Singapore
| | - R T P Lin
- Department of Laboratory Medicine, National University Hospital, Singapore.,National Public Health Laboratory, National Centre for Infectious Diseases, Singapore
| | - J W P Teo
- Department of Laboratory Medicine, National University Hospital, Singapore
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82
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Germination of a Field: Women in Candida albicans Research. CURRENT CLINICAL MICROBIOLOGY REPORTS 2021. [DOI: 10.1007/s40588-021-00169-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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83
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Hospital outbreak of fluconazole-resistant Candida parapsilosis: arguments for clonal transmission and long-term persistence. Antimicrob Agents Chemother 2021; 95:AAC.02036-20. [PMID: 33593841 PMCID: PMC8092880 DOI: 10.1128/aac.02036-20] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The worldwide emergence of multidrug-resistant pathogenic fungi is a threat to human health. At this very moment, an emergence of Candida parapsilosis isolates harbouring a resistance to fluconazole, one of the most popular antifungal drugs, is being described in several countries. We seek to better understanding the epidemiology, pathogenicity and transmission of resistant Candida parapsilosis Faced with an outbreak of invasive infections due to resistant isolates of C. parapsilosis, we performed a 7-year retrospective and prospective analysis of 283 C. parapsilosis isolates collected in 240 patients, among who 111 had invasive candidiasis. Study included review of hospital records, genotyping analysis and susceptibility testing that allow determining the type and outcome of infections, as well as the spatial and temporal spread of clusters. Overall the incidence of azole resistance was 7.5%. Genotyping analysis unveiled several previously undetected outbreaks and clonal spread of susceptible and resistant isolates over a long period of time. In comparison with susceptible isolates, resistant ones have a more restricted genetic diversity and seem to be more likely to spread and more frequently associated with invasive infections. In intensive care units, patients with invasive infections due to resistant isolates had poorer outcome (overall mortality at day 30 of 40%; 4/10) than susceptible ones (overall mortality at day 30 of 26.5%; 9/34). Our results suggest that the propensity of C. parapsilosis to spread on an epidemic fashion is underestimated, which warrants reinforced control and epidemiological survey of this species.
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84
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Lee Y, Puumala E, Robbins N, Cowen LE. Antifungal Drug Resistance: Molecular Mechanisms in Candida albicans and Beyond. Chem Rev 2021; 121:3390-3411. [PMID: 32441527 PMCID: PMC8519031 DOI: 10.1021/acs.chemrev.0c00199] [Citation(s) in RCA: 340] [Impact Index Per Article: 113.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Fungal infections are a major contributor to infectious disease-related deaths across the globe. Candida species are among the most common causes of invasive mycotic disease, with Candida albicans reigning as the leading cause of invasive candidiasis. Given that fungi are eukaryotes like their human host, the number of unique molecular targets that can be exploited for antifungal development remains limited. Currently, there are only three major classes of drugs approved for the treatment of invasive mycoses, and the efficacy of these agents is compromised by the development of drug resistance in pathogen populations. Notably, the emergence of additional drug-resistant species, such as Candida auris and Candida glabrata, further threatens the limited armamentarium of antifungals available to treat these serious infections. Here, we describe our current arsenal of antifungals and elaborate on the resistance mechanisms Candida species possess that render them recalcitrant to therapeutic intervention. Finally, we highlight some of the most promising therapeutic strategies that may help combat antifungal resistance, including combination therapy, targeting fungal-virulence traits, and modulating host immunity. Overall, a thorough understanding of the mechanistic principles governing antifungal drug resistance is fundamental for the development of novel therapeutics to combat current and emerging fungal threats.
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Affiliation(s)
- Yunjin Lee
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, Ontario M5G 1M1, Canada
| | - Emily Puumala
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, Ontario M5G 1M1, Canada
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, Ontario M5G 1M1, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, Ontario M5G 1M1, Canada
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85
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Capric acid secreted by Saccharomyces boulardii influences the susceptibility of Candida albicans to fluconazole and amphotericin B. Sci Rep 2021; 11:6519. [PMID: 33753842 PMCID: PMC7985486 DOI: 10.1038/s41598-021-86012-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 03/08/2021] [Indexed: 12/20/2022] Open
Abstract
The effect of capric acid, secreted by the probiotic yeasts Saccharomyces boulardii, was evaluated on the activities of fluconazole (FLC) and amphotericin B (AMB) against pathogenic Candida albicans fungus. The findings indicated that capric acid may be a promising additive for use in combination with FLC. A FLC-capric acid combination led to reduced efflux activity of multidrug resistance (MDR) transporter Cdr1p by causing it to relocalize from the plasma membrane (PM) to the interior of the cell. The above effect occurred due to inhibitory effect of FLC-capric acid combination of ergosterol biosynthesis. However, capric acid alone stimulated ergosterol production in C. albicans, which in turn generated cross resistance towards AMB and inhibited its action (PM permeabilization and cytoplasm leakage) against C. albicans cells. This concluded that AMB should not be administered among dietary supplements containing capric acid or S. boulardii cells.
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86
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Demin KA, Refeld AG, Bogdanova AA, Prazdnova EV, Popov IV, Kutsevalova OY, Ermakov AM, Bren AB, Rudoy DV, Chistyakov VA, Weeks R, Chikindas ML. Mechanisms of Candida Resistance to Antimycotics and Promising Ways to Overcome It: The Role of Probiotics. Probiotics Antimicrob Proteins 2021; 13:926-948. [PMID: 33738706 DOI: 10.1007/s12602-021-09776-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/09/2021] [Indexed: 12/12/2022]
Abstract
Pathogenic Candida and infections caused by those species are now considered as a serious threat to public health. The treatment of candidiasis is significantly complicated by the increasing resistance of pathogenic strains to current treatments and the stagnant development of new antimycotic drugs. Many species, such as Candida auris, have a wide range of resistance mechanisms. Among the currently used synthetic and semi-synthetic antifungal drugs, the most effective are azoles, echinocandins, polyenes, nucleotide analogs, and their combinations. However, the use of probiotic microorganisms and/or the compounds they produce is quite promising, although underestimated by modern pharmacology, to control the spread of pathogenic Candida species.
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Affiliation(s)
- Konstantin A Demin
- Academy of Biology and Biotechnology, Southern Federal University, Rostov-on-Don, Russia
| | - Aleksandr G Refeld
- Academy of Biology and Biotechnology, Southern Federal University, Rostov-on-Don, Russia
| | - Anna A Bogdanova
- Academy of Biology and Biotechnology, Southern Federal University, Rostov-on-Don, Russia
| | - Evgenya V Prazdnova
- Academy of Biology and Biotechnology, Southern Federal University, Rostov-on-Don, Russia
| | - Igor V Popov
- Center for Agrobiotechnology, Don State Technical University, Rostov-on-Don, Russia
| | | | - Alexey M Ermakov
- Center for Agrobiotechnology, Don State Technical University, Rostov-on-Don, Russia
| | - Anzhelica B Bren
- Academy of Biology and Biotechnology, Southern Federal University, Rostov-on-Don, Russia.,Center for Agrobiotechnology, Don State Technical University, Rostov-on-Don, Russia
| | - Dmitry V Rudoy
- Center for Agrobiotechnology, Don State Technical University, Rostov-on-Don, Russia
| | - Vladimir A Chistyakov
- Academy of Biology and Biotechnology, Southern Federal University, Rostov-on-Don, Russia
| | - Richard Weeks
- Health Promoting Naturals Laboratory, School of Environmental and Biological Sciences, Rutgers State University, New Brunswick, NJ, USA
| | - Michael L Chikindas
- Center for Agrobiotechnology, Don State Technical University, Rostov-on-Don, Russia. .,Health Promoting Naturals Laboratory, School of Environmental and Biological Sciences, Rutgers State University, New Brunswick, NJ, USA. .,I.M. Sechenov First Moscow State Medical University, Moscow, Russia.
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87
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Azole-triphenylphosphonium conjugates combat antifungal resistance and alleviate the development of drug-resistance. Bioorg Chem 2021; 110:104771. [PMID: 33714761 DOI: 10.1016/j.bioorg.2021.104771] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 02/05/2021] [Accepted: 02/21/2021] [Indexed: 11/24/2022]
Abstract
Azole antifungals are commonly used to treat fungal infections but have resulted in the occurrence of drug resistance. Therefore, developing azole derivatives (AZDs) that can both combat established drug-resistant fungal strains and evade drug resistance is of great importance. In this study, we synthesized a series of AZDs with a fluconazole (FLC) skeleton conjugated with a mitochondria-targeting triphenylphosphonium cation (TPP+). These AZDs displayed potent activity against both azole-sensitive and azole-resistant Candida strains without eliciting obvious resistance. Moreover, two representative AZDs, 20 and 25, exerted synergistic antifungal activity with Hsp90 inhibitors against C. albicans strains resistant to the combination treatment of FLC and Hsp90 inhibitors. AZD 25, which had minimal cytotoxicity, was effective in preventing C. albicans biofilm formation. Mechanistic investigation revealed that AZD 25 inhibited the biosynthesis of the fungal membrane component ergosterol and interfered with mitochondrial function. Our findings provide an alternative approach to address fungal resistance problems.
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88
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Characterization of Aspergillus fumigatus cross-resistance between clinical and DMI azole drugs. Appl Environ Microbiol 2021; 87:AEM.02539-20. [PMID: 33355104 PMCID: PMC8090891 DOI: 10.1128/aem.02539-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Drug resistance poses a serious threat to human health and agricultural production. Azole drugs are the largest group of 14-α sterol demethylation inhibitor fungicides that are used both in agriculture and in clinical practice. As plant pathogenic molds share their natural environment with fungi that cause opportunistic infections in humans, both are exposed to a strong and persistent pressure of demethylase inhibitor (DMI) fungicides, including imidazole and triazole drugs. As a result, a loss of efficacy has occurred for this drug class in several species. In the clinical setting, Aspergillus fumigatus azole resistance is a growing public health problem and finding the source of this resistance has gained much attention. It is urgent to determine if there is a direct link between the agricultural use of azole compounds and the different A. fumigatus resistance mechanisms described for clinical triazoles. In this work we have performed A. fumigatus susceptibility testing to clinical triazoles and crop protection DMIs using a collection of azole susceptible and resistant strains which harbor most of the described azole resistance mechanisms. Various DMI susceptibility profiles have been found in the different A. fumigatus populations groups based on their azole resistance mechanism and previous WGS analysis, which suggests that the different resistance mechanisms have different origins and are specifically associated to the local use of a particular DMI.Importance Due to the worldwide emergence of A. fumigatus azole resistance, this opportunistic pathogen poses a serious health threat and, therefore, it has been included in the Watch List of the CDC 2019 Antimicrobial Resistance Threats Report. Azoles play a critical role in the control and management of fungal diseases, not only in the clinical setting but also in agriculture. Thus, azole resistance leads to a limited therapeutic arsenal which reduces the treatment options for aspergillosis patients, increasing their mortality risk. Evidence is needed to understand whether A. fumigatus azole resistance is emerging from an agricultural source due to the extended use of demethylase inhibitors as fungicides, or whether it is coming from somewhere else such as the clinical setting. If the environmental route is demonstrated, the current use and management of azole antifungal compounds might be forced to change in the forthcoming years.
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89
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Scorzoni L, Fuchs BB, Junqueira JC, Mylonakis E. Current and promising pharmacotherapeutic options for candidiasis. Expert Opin Pharmacother 2021; 22:867-887. [PMID: 33538201 DOI: 10.1080/14656566.2021.1873951] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Introduction: Candida spp. are commensal yeasts capable of causing infections such as superficial, oral, vaginal, or systemic infections. Despite medical advances, the antifungal pharmacopeia remains limited and the development of alternative strategies is needed.Areas covered: We discuss available treatments for Candida spp. infections, highlighting advantages and limitations related to pharmacokinetics, cytotoxicity, and antimicrobial resistance. Moreover, we present new perspectives to improve the activity of the available antifungals, discussing their immunomodulatory potential and advances on drug delivery carriers. New therapeutic approaches are presented including recent synthesized antifungal compounds (Enchochleated-Amphotericin B, tetrazoles, rezafungin, enfumafungin, manogepix and arylamidine); drug repurposing using a diversity of antibacterial, antiviral and non-antimicrobial drugs; combination therapies with different compounds or photodynamic therapy; and innovations based on nano-particulate delivery systems.Expert opinion: With the lack of novel drugs, the available assets must be leveraged to their best advantage through modifications that enhance delivery, efficacy, and solubility. However, these efforts are met with continuous challenges presented by microbes in their infinite plight to resist and survive therapeutic drugs. The pharmacotherapeutic options in development need to focus on new antimicrobial targets. The success of each antimicrobial agent brings strategic insights to the next phased approach in treatingCandida spp. infections.
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Affiliation(s)
- Liliana Scorzoni
- Department of Biosciences and Oral Diagnosis, Institute of Science and Technology, São Paulo State University/UNESP, SP Brazil
| | - Beth Burgwyn Fuchs
- Division of Infectious Diseases, Rhode Island Hospital, Alpert Medical School, Brown University, Providence, RI USA
| | - Juliana Campos Junqueira
- Department of Biosciences and Oral Diagnosis, Institute of Science and Technology, São Paulo State University/UNESP, SP Brazil
| | - Eleftherios Mylonakis
- Division of Infectious Diseases, Rhode Island Hospital, Alpert Medical School, Brown University, Providence, RI USA
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90
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Du M, Hu W, Tamura T, Alshahni MM, Satoh K, Yamanishi C, Naito T, Makimura K. Investigation of the Physiological, Biochemical and Antifungal Susceptibility Properties of Candida auris. Mycopathologia 2021; 186:189-198. [PMID: 33475901 DOI: 10.1007/s11046-020-00526-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 12/28/2020] [Indexed: 11/29/2022]
Abstract
BACKGROUND Candida auris is an emerging pathogen associated with outbreaks in clinical settings. Isolates of the pathogen have been geographically clustered into four clades with high intra-clade clonality. Pathogenicity varies among the clades, highlighting the importance of understanding these differences. OBJECTIVES To examine the physiological and biochemical properties of each clade of C. auris to improve our understanding of the fungus. METHODS Optimal growth temperatures of four strains from three clades, East Asia, South Asia and South Africa, were explored. Moreover, assimilation and antifungal susceptibility properties of 22 C. auris strains from the three clades were studied. RESULTS The optimal growth temperatures of all strains were 35-37 °C. Assimilation testing demonstrated that the commercial API ID 32 C system can be used to reliably identify C. auris based on the biochemical properties of the yeast. Notably, C. auris can be uniquely differentiated from commonly clinical fungi by its ability to assimilate raffinose and inability to utilize D-xylose, suggesting a useful simple screening tool. The antifungal susceptibility results revealed that all strains are resistant against fluconazole (minimal inhibitory concentration (MIC) 4 to > 64 µg/mL) and miconazole (MIC 8 to > 16 µg/mL), with strains from the Japanese lineage showing relatively lower MIC values (1-4 µg/mL). Conversely, itraconazole, voriconazole, amphotericin B, micafungin and caspofungin were active against most of the tested strains. On the clade level, East Asian strains generally showed lower MICs against azoles comparing to the other clades, while they displayed MICs against flucytosine higher than those of strains from South Africa and South Asia clades. CONCLUSION Our data suggest a simple identification approach of C. auris based on its physiological and biochemical properties and highlight aspects of C. auris population from various clades.
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Affiliation(s)
- Mengqian Du
- General Medical Education and Research Center, Teikyo University, 2-11-1 Kaga, Itabashi, Tokyo, 173-8605, Japan.,General Medicine, Graduate School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo, Tokyo, 113-8421, Japan
| | - Weimin Hu
- General Medical Education and Research Center, Teikyo University, 2-11-1 Kaga, Itabashi, Tokyo, 173-8605, Japan.,Institute of Basic Medicine, Shandong First Medical University, 18877 Jingshi Road, Jinan, 250062, People's Republic of China.,Weifang City Key Laboratory of Medical Mycology, Biotech and Pharmaceutical Industrial Park, Hi-Tech Development Zone, Weifang, Shandong, 261061, People's Republic of China
| | - Takashi Tamura
- General Medical Education and Research Center, Teikyo University, 2-11-1 Kaga, Itabashi, Tokyo, 173-8605, Japan
| | - Mohamed Mahdi Alshahni
- Laboratory of Medical Mycology and Space Environmental Medicine, Graduate School of Medicine, Teikyo University, 2-11-1 Kaga, Itabashi, Tokyo, 173-8605, Japan.,Department of AMR Mycosis Control Research in the Environment of Treatment and Education for Physically and Mentally Handicapped Persons, School of Medicine, Teikyo University, 2-11-1 Kaga, Itabashi, Tokyo, 173-8605, Japan
| | - Kazuo Satoh
- General Medical Education and Research Center, Teikyo University, 2-11-1 Kaga, Itabashi, Tokyo, 173-8605, Japan.,Laboratory of Medical Mycology and Space Environmental Medicine, Graduate School of Medicine, Teikyo University, 2-11-1 Kaga, Itabashi, Tokyo, 173-8605, Japan
| | - Chiaki Yamanishi
- General Medical Education and Research Center, Teikyo University, 2-11-1 Kaga, Itabashi, Tokyo, 173-8605, Japan
| | - Toshio Naito
- General Medicine, Graduate School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo, Tokyo, 113-8421, Japan
| | - Koichi Makimura
- General Medical Education and Research Center, Teikyo University, 2-11-1 Kaga, Itabashi, Tokyo, 173-8605, Japan. .,Laboratory of Medical Mycology and Space Environmental Medicine, Graduate School of Medicine, Teikyo University, 2-11-1 Kaga, Itabashi, Tokyo, 173-8605, Japan. .,Department of AMR Mycosis Control Research in the Environment of Treatment and Education for Physically and Mentally Handicapped Persons, School of Medicine, Teikyo University, 2-11-1 Kaga, Itabashi, Tokyo, 173-8605, Japan.
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91
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Monk BC, Keniya MV. Roles for Structural Biology in the Discovery of Drugs and Agrochemicals Targeting Sterol 14α-Demethylases. J Fungi (Basel) 2021; 7:67. [PMID: 33498194 PMCID: PMC7908997 DOI: 10.3390/jof7020067] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/08/2021] [Accepted: 01/17/2021] [Indexed: 02/06/2023] Open
Abstract
Antifungal drugs and antifungal agrochemicals have significant limitations. These include several unintended consequences of their use including the growing importance of intrinsic and acquired resistance. These problems underpin an increasingly urgent need to improve the existing classes of antifungals and to discover novel antifungals. Structural insights into drug targets and their complexes with both substrates and inhibitory ligands increase opportunity for the discovery of more effective antifungals. Implementation of this promise, which requires multiple skill sets, is beginning to yield candidates from discovery programs that could more quickly find their place in the clinic. This review will describe how structural biology is providing information for the improvement and discovery of inhibitors targeting the essential fungal enzyme sterol 14α-demethylase.
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Affiliation(s)
- Brian C. Monk
- Department of Oral Sciences, Sir John Walsh Research Institute, University of Otago, Dunedin 9016, New Zealand;
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92
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Prakash SMU, Nazeer Y, Jayanthi S, Kabir MA. Computational insights into fluconazole resistance by the suspected mutations in lanosterol 14α-demethylase (Erg11p) of Candida albicans. MOLECULAR BIOLOGY RESEARCH COMMUNICATIONS 2020; 9:155-167. [PMID: 33344662 PMCID: PMC7731972 DOI: 10.22099/mbrc.2020.36298.1476] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Mutations in the ergosterol biosynthesis gene 11 (ERG11) of Candida albicans have been frequently reported in fluconazole-resistant clinical isolates. Exploring the mutations and their effect could provide new insights into the underlying mechanism of fluconazole resistance. Erg11p_Threonine285Alanine (Erg11p_THR285ALA), Erg11p_Leucine321Phenylalanine (Erg11p_LEU321PHE) and Erg11p_Serine457Proline (Erg11p_SER457PRO) are three fluconazole-resistant suspected mutations reported in clinical isolates of C. albicans. Therefore, our study aims to investigate the role of these suspected mutations in fluconazole resistance using in-silico methods. Molecular dynamics simulation (MDS) analysis of apo-protein for 25ns (nanosecond) showed that suspected mutant proteins underwent slight conformational changes in the tertiary structure. Molecular docking with fluconazole followed by binding free energy analysis showed reduced non-bonded interactions with loss of heme interaction and the least binding affinity for Erg11p_SER457PRO mutation. MDS of suspected mutant proteins-fluconazole complexes for 50ns revealed that Erg11p_SER457PRO and Erg11p_LEU321PHE have clear differences in the interaction pattern and loss or reduced heme interaction compared to wild type Erg11p-fluconazole complex. MDS and binding free energy analysis of Erg11p_SER457PRO-fluconazole complex showed the least binding similar to verified mutation Erg11p_TYR447HIS-fluconazole complex. Taken together, our study concludes that suspected mutation Erg11p_THR285ALA may not have any role whereas Erg11p_LEU321PHE could have a moderate role. However, Erg11p_SER457PRO mutation has a strong possibility to play an active role in fluconazole resistance of C. albicans.
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Affiliation(s)
| | - Yasin Nazeer
- Regional Medical Research Centre, Indian Council of Medical Research (ICMR), Belagavi -590010, Karnataka, India
| | - Sivaraman Jayanthi
- Computational Drug Design Lab, School of BioSciences and Technology, Vellore Institute of Technology, Vellore-632014, Tamil Nadu, India
| | - Mohammad Anaul Kabir
- Molecular Genetics Laboratory, School of Biotechnology, National Institute of Technology Calicut, Calicut 673601, Kerala, India
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93
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Rosam K, Monk BC, Lackner M. Sterol 14α-Demethylase Ligand-Binding Pocket-Mediated Acquired and Intrinsic Azole Resistance in Fungal Pathogens. J Fungi (Basel) 2020; 7:jof7010001. [PMID: 33374996 PMCID: PMC7822023 DOI: 10.3390/jof7010001] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 12/17/2020] [Accepted: 12/18/2020] [Indexed: 12/17/2022] Open
Abstract
The fungal cytochrome P450 enzyme sterol 14α-demethylase (SDM) is a key enzyme in the ergosterol biosynthesis pathway. The binding of azoles to the active site of SDM results in a depletion of ergosterol, the accumulation of toxic intermediates and growth inhibition. The prevalence of azole-resistant strains and fungi is increasing in both agriculture and medicine. This can lead to major yield loss during food production and therapeutic failure in medical settings. Diverse mechanisms are responsible for azole resistance. They include amino acid (AA) substitutions in SDM and overexpression of SDM and/or efflux pumps. This review considers AA affecting the ligand-binding pocket of SDMs with a primary focus on substitutions that affect interactions between the active site and the substrate and inhibitory ligands. Some of these interactions are particularly important for the binding of short-tailed azoles (e.g., voriconazole). We highlight the occurrence throughout the fungal kingdom of some key AA substitutions. Elucidation of the role of these AAs and their substitutions may assist drug design in overcoming some common forms of innate and acquired azole resistance.
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Affiliation(s)
- Katharina Rosam
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Schöpfstrasse 41, 6020 Innsbruck, Austria;
| | - Brian C. Monk
- Sir John Walsh Research Institute and Department of Oral Biology, Faculty of Dentistry, University of Otago, PO Box 56, 9054 Dunedin, New Zealand;
| | - Michaela Lackner
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Schöpfstrasse 41, 6020 Innsbruck, Austria;
- Correspondence: ; Tel.: +43-512-003-70725
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94
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Iyer KR, Camara K, Daniel-Ivad M, Trilles R, Pimentel-Elardo SM, Fossen JL, Marchillo K, Liu Z, Singh S, Muñoz JF, Kim SH, Porco JA, Cuomo CA, Williams NS, Ibrahim AS, Edwards JE, Andes DR, Nodwell JR, Brown LE, Whitesell L, Robbins N, Cowen LE. An oxindole efflux inhibitor potentiates azoles and impairs virulence in the fungal pathogen Candida auris. Nat Commun 2020; 11:6429. [PMID: 33353950 PMCID: PMC7755909 DOI: 10.1038/s41467-020-20183-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 11/12/2020] [Indexed: 12/11/2022] Open
Abstract
Candida auris is an emerging fungal pathogen that exhibits resistance to multiple drugs, including the most commonly prescribed antifungal, fluconazole. Here, we use a combinatorial screening approach to identify a bis-benzodioxolylindolinone (azoffluxin) that synergizes with fluconazole against C. auris. Azoffluxin enhances fluconazole activity through the inhibition of efflux pump Cdr1, thus increasing intracellular fluconazole levels. This activity is conserved across most C. auris clades, with the exception of clade III. Azoffluxin also inhibits efflux in highly azole-resistant strains of Candida albicans, another human fungal pathogen, increasing their susceptibility to fluconazole. Furthermore, azoffluxin enhances fluconazole activity in mice infected with C. auris, reducing fungal burden. Our findings suggest that pharmacologically targeting Cdr1 in combination with azoles may be an effective strategy to control infection caused by azole-resistant isolates of C. auris.
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Affiliation(s)
- Kali R Iyer
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Kaddy Camara
- Department of Chemistry and Center for Molecular Discovery (BU-CMD), Boston University, Boston, MA, USA
- Clark+Elbing LLP, Boston, MA, USA
| | | | - Richard Trilles
- Department of Chemistry and Center for Molecular Discovery (BU-CMD), Boston University, Boston, MA, USA
| | | | - Jen L Fossen
- Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI, USA
| | - Karen Marchillo
- Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI, USA
| | - Zhongle Liu
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Shakti Singh
- Division of Infectious Disease, The Lundquist Institute for Biomedical Innovation Los Angeles Biomedical Research Institute at Harbor-University of California, Los Angeles (UCLA) Medical Center, Torrance, CA, USA
| | - José F Muñoz
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Sang Hu Kim
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - John A Porco
- Department of Chemistry and Center for Molecular Discovery (BU-CMD), Boston University, Boston, MA, USA
| | - Christina A Cuomo
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Noelle S Williams
- Department of Biochemistry, University of Texas Southwestern Medical School, Dallas, TX, USA
| | - Ashraf S Ibrahim
- Division of Infectious Disease, The Lundquist Institute for Biomedical Innovation Los Angeles Biomedical Research Institute at Harbor-University of California, Los Angeles (UCLA) Medical Center, Torrance, CA, USA
- David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - John E Edwards
- Division of Infectious Disease, The Lundquist Institute for Biomedical Innovation Los Angeles Biomedical Research Institute at Harbor-University of California, Los Angeles (UCLA) Medical Center, Torrance, CA, USA
- David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - David R Andes
- Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI, USA
| | - Justin R Nodwell
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Lauren E Brown
- Department of Chemistry and Center for Molecular Discovery (BU-CMD), Boston University, Boston, MA, USA
| | - Luke Whitesell
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada.
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95
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Binder U, Arastehfar A, Schnegg L, Hörtnagl C, Hilmioğlu-Polat S, Perlin DS, Lass-Flörl C. Efficacy of LAMB against Emerging Azole- and Multidrug-Resistant Candida parapsilosis Isolates in the Galleria mellonella Model. J Fungi (Basel) 2020; 6:E377. [PMID: 33353200 PMCID: PMC7767002 DOI: 10.3390/jof6040377] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/16/2020] [Accepted: 12/17/2020] [Indexed: 12/14/2022] Open
Abstract
While being the third leading cause of candidemia worldwide, numerous studies have shown severe clonal outbreaks due to fluconazole-resistant (FLCR) Candida parapsilosis isolates associated with fluconazole therapeutic failure (FTF) with enhanced mortality. More recently, multidrug resistant (MDR) C. parapsilosis blood isolates have also been identified that are resistant to both azole and echinocandin drugs. Amphotericin B (AMB) resistance is rarely reported among C. parapsilosis isolates and proper management of bloodstream infections due to FLZR and MDR isolates requires prompt action at the time of outbreak. Therefore, using a well-established Galleria mellonella model, we assessed whether (a) laboratory-based findings on azole or echinocandin (micafungin) resistance in C. parapsilosis lead to therapeutic failure, (b) LAMB could serve as an efficient salvage treatment option, and (c) distinct mutations in ERG11 impact mortality. Our in vivo data confirm fluconazole inefficacy against FLCR C. parapsilosis isolates carrying Y132F, Y132F + K143R, Y132F + G307A, and G307A + G458S in Erg11p, while LAMB proved to be an efficacious accessible option against both FLCR and MDR C. parapsilosis isolates. Moreover, positive correlation of in vitro and in vivo data further highlights the utility of G. melonella as a reliable model to investigate azole and polyene drug efficacy.
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Affiliation(s)
- Ulrike Binder
- Institute of Hygiene and Medical Microbiology, Medical University Innsbruck, Schöpfstrasse 41, 6020 Innsbruck, Austria; (L.S.); (C.H.); (C.L.-F.)
| | - Amir Arastehfar
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ 07110, USA; (A.A.); (D.S.P.)
| | - Lisa Schnegg
- Institute of Hygiene and Medical Microbiology, Medical University Innsbruck, Schöpfstrasse 41, 6020 Innsbruck, Austria; (L.S.); (C.H.); (C.L.-F.)
| | - Caroline Hörtnagl
- Institute of Hygiene and Medical Microbiology, Medical University Innsbruck, Schöpfstrasse 41, 6020 Innsbruck, Austria; (L.S.); (C.H.); (C.L.-F.)
| | | | - David S. Perlin
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ 07110, USA; (A.A.); (D.S.P.)
| | - Cornelia Lass-Flörl
- Institute of Hygiene and Medical Microbiology, Medical University Innsbruck, Schöpfstrasse 41, 6020 Innsbruck, Austria; (L.S.); (C.H.); (C.L.-F.)
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Fernandes CM, Poeta MD. Fungal sphingolipids: role in the regulation of virulence and potential as targets for future antifungal therapies. Expert Rev Anti Infect Ther 2020; 18:1083-1092. [PMID: 32673125 PMCID: PMC7657966 DOI: 10.1080/14787210.2020.1792288] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 07/02/2020] [Indexed: 12/17/2022]
Abstract
INTRODUCTION The antifungal therapy currently available includes three major classes of drugs: polyenes, azoles and echinocandins. However, the clinical use of these compounds faces several challenges: while polyenes are toxic to the host, antifungal resistance to azoles and echinocandins has been reported. AREAS COVERED Fungal sphingolipids (SL) play a pivotal role in growth, morphogenesis and virulence. In addition, fungi possess unique enzymes involved in SL synthesis, leading to the production of lipids which are absent or differ structurally from the mammalian counterparts. In this review, we address the enzymatic reactions involved in the SL synthesis and their relevance to the fungal pathogenesis, highlighting their potential as targets for novel drugs and the inhibitors described so far. EXPERT OPINION The pharmacological inhibition of fungal serine palmitoyltransferase depends on the development of specific drugs, as myriocin also targets the mammalian enzyme. Inhibitors of ceramide synthase might constitute potent antifungals, by depleting the pool of complex SL and leading to the accumulation of the toxic intermediates. Acylhydrazones and aureobasidin A, which inhibit GlcCer and IPC synthesis, are not toxic to the host and effectively treat invasive mycoses, emerging as promising new classes of antifungal drugs.
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Affiliation(s)
| | - Maurizio Del Poeta
- Department of Microbiology and Immunology, Stony Brook University, NY, USA
- Division of Infectious Diseases, School of Medicine, Stony Brook University, NY, USA
- Veterans Administration Medical Center, Northport, NY, USA
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97
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Evaluation of Two Commercial Broth Microdilution Methods Using Different Interpretive Criteria for the Detection of Molecular Mechanisms of Acquired Azole and Echinocandin Resistance in Four Common Candida Species. Antimicrob Agents Chemother 2020; 64:AAC.00740-20. [PMID: 32900684 DOI: 10.1128/aac.00740-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 08/31/2020] [Indexed: 01/05/2023] Open
Abstract
The abilities of the new Vitek 2 AST-YS08 (YS08) and Sensititre YeastOne (SYO) systems to detect the resistances of Candida isolates to azoles and echinocandins were evaluated. In total, 292 isolates, including 28 Candida albicans (6 Erg11 and 2 Fks mutants), 57 Candida parapsilosis (26 Erg11 mutants), 24 Candida tropicalis (10 Erg11 and 1 Fks mutants), and 183 Candida glabrata (39 Pdr1 and 13 Fks mutants) isolates, were tested. The categorical agreements (CAs) between the Clinical and Laboratory Standards Institute (CLSI) method and YS08 fluconazole MICs obtained using clinical breakpoints were 92.4% (C. albicans), 96.5% (C. parapsilosis), and 87.0% (C. tropicalis), and the CAs between the CLSI and SYO MICs were 92.3% (C. albicans), 77.2% (C. parapsilosis), 100% (C. tropicalis), and 98.9% (C. glabrata). For C. glabrata, the CAs with the CLSI micafungin MICs were 92.4% and 55.5% for the YS08 micafungin and caspofungin MICs, respectively; they were 100%, 95.6%, and 98.9% for the SYO micafungin, caspofungin, and anidulafungin MICs, respectively. YS08 does not provide fluconazole data for C. glabrata; the CA with the CLSI fluconazole MIC was 97.8% for the YS08 voriconazole MIC, using an epidemiological cutoff value (ECV) of 0.5 μg/ml. Increased CAs with the CLSI MIC were observed for the YS08 MIC using CLSI ECVs (for fluconazole and C. tropicalis, 100%; for micafungin and C. glabrata, 98.9%) and for the SYO MIC using method-specific ECVs (for fluconazole and C. parapsilosis, 91.2%; for caspofungin and C. glabrata, 98.9%). Therefore, the YS08 and SYO systems may have different abilities to detect mechanisms of azole and echinocandin resistance in four Candida species; the use of method-specific ECVs may improve the performance of both systems.
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98
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Insights into the Multi-Azole Resistance Profile in Candida haemulonii Species Complex. J Fungi (Basel) 2020; 6:jof6040215. [PMID: 33050545 PMCID: PMC7711680 DOI: 10.3390/jof6040215] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 10/06/2020] [Accepted: 10/08/2020] [Indexed: 12/25/2022] Open
Abstract
The Candida haemulonii complex (C. duobushaemulonii, C. haemulonii, and C. haemulonii var. vulnera) is composed of emerging, opportunistic human fungal pathogens able to cause invasive infections with high rates of clinical treatment failure. This fungal complex typically demonstrates resistance to first-line antifungals, including fluconazole. In the present work, we have investigated the azole resistance mechanisms expressed in Brazilian clinical isolates forming the C. haemulonii complex. Initially, 12 isolates were subjected to an antifungal susceptibility test, and azole cross-resistance was detected in almost all isolates (91.7%). In order to understand the azole resistance mechanistic basis, the efflux pump activity was assessed by rhodamine-6G. The C. haemulonii complex exhibited a significantly higher rhodamine-6G efflux than the other non-albicans Candida species tested (C. tropicalis, C. krusei, and C. lusitaneae). Notably, the efflux pump inhibitors (Phe-Arg and FK506) reversed the fluconazole and voricolazole resistance phenotypes in the C. haemulonii species complex. Expression analysis indicated that the efflux pump (ChCDR1, ChCDR2, and ChMDR1) and ERG11 genes were not modulated by either fluconazole or voriconazole treatments. Further, ERG11 gene sequencing revealed several mutations, some of which culminated in amino acid polymorphisms, as previously reported in azole-resistant Candida spp. Collectively, these data point out the relevance of drug efflux pumps in mediating azole resistance in the C. haemulonii complex, and mutations in ERG11p may contribute to this resistance profile.
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99
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Osman Mohamed A, Suliman Mohamed M, Abdelrahman Hussain M, Fatahalrahman Ahmed I. Detection of antifungal drug-resistant and ERG11 gene mutations among clinical isolates of Candida species isolated from Khartoum, Sudan. F1000Res 2020; 9:1050. [PMID: 34035903 PMCID: PMC8114185 DOI: 10.12688/f1000research.24854.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/22/2021] [Indexed: 11/20/2022] Open
Abstract
Background:
Candida species are one of the most important opportunistic fungal pathogens that cause both superficial and systemic infections, especially in immunocompromised individuals. Considering the sharp increase in the rate of
Candida infections, and resistance to commonly used antifungal agents in the last decades; this study was conducted to determine the rate of resistance among clinical isolates of
Candida species, and to characterize some of the resistant genes among resistant isolates collected in Khartoum. Methods: This is a cross-sectional laboratory-based study included 100 pre-screened
Candida species isolates from Khartoum state hospitals. Chromogenic media was used for
Candida isolation and/or identification. The standard disc diffusion method was performed to investigate the susceptibility to fluconazole, itraconazole, and amphotericin. Following genomic DNA extraction, the entire
ERG11 gene was amplified from some
C. albicans resistant isolates, sequenced, and further analyzed. Results: Out of 100 clinical isolates collected, 51% were
C. albicans, followed by
C. glabrata (31%),
C. krusie (8%),
C. tropicals (5%), and
C. dupliniens (5%). Resistance rate was 23% for fluconazole, 4% for itraconazole, while there were no amphotericin resistant isolates detected.
C. albicans
ERG11 gene sequence reveals 15 different mutations. Among these, three (D116E, E266D, and V488I) were missense mutations; however, these substitutions do not contribute to fluconazole resistance. Conclusion:
C. albicans was found to be the most common species. Resistance against fluconazole was observed most frequently; however, mutations in
ERG11 are unlikely to be the reason behind fluconazole resistance among these isolates.
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Affiliation(s)
- Ahmed Osman Mohamed
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, International University of Africa, Khartoum, 11111, Sudan.,Department of Pharmaceutics, Faculty of Pharmacy, Sudan International University, Khartoum, 11111, Sudan
| | - Malik Suliman Mohamed
- Department of Pharmaceutics, College of Pharmacy, Jouf University, Sakaka, Al Jouf, P.O.Box 2014, Saudi Arabia.,Department of Pharmaceutics, Faculty of Pharmacy, University of Khartoum, Khartoum, P. O. Box 1996, Sudan
| | - Mohamed Abdelrahman Hussain
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, International University of Africa, Khartoum, 11111, Sudan
| | - Ibrahim Fatahalrahman Ahmed
- Department of Microbiology, Faculty of Pure and Applied Science, International University of Africa, Khartoum, 11111, Sudan
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Todd RT, Selmecki A. Expandable and reversible copy number amplification drives rapid adaptation to antifungal drugs. eLife 2020; 9:e58349. [PMID: 32687060 PMCID: PMC7371428 DOI: 10.7554/elife.58349] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 07/09/2020] [Indexed: 12/13/2022] Open
Abstract
Previously, we identified long repeat sequences that are frequently associated with genome rearrangements, including copy number variation (CNV), in many diverse isolates of the human fungal pathogen Candida albicans (Todd et al., 2019). Here, we describe the rapid acquisition of novel, high copy number CNVs during adaptation to azole antifungal drugs. Single-cell karyotype analysis indicates that these CNVs appear to arise via a dicentric chromosome intermediate and breakage-fusion-bridge cycles that are repaired using multiple distinct long inverted repeat sequences. Subsequent removal of the antifungal drug can lead to a dramatic loss of the CNV and reversion to the progenitor genotype and drug susceptibility phenotype. These findings support a novel mechanism for the rapid acquisition of antifungal drug resistance and provide genomic evidence for the heterogeneity frequently observed in clinical settings.
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Affiliation(s)
- Robert T Todd
- Department of Microbiology and Immunology, University of Minnesota Medical SchoolMinneapolis, MinnesotaUnited States
| | - Anna Selmecki
- Department of Microbiology and Immunology, University of Minnesota Medical SchoolMinneapolis, MinnesotaUnited States
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