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Ni Q, Wang C, Tian Y, Dong D, Jiang C, Mao E, Peng Y. CgPDR1 gain-of-function mutations lead to azole-resistance and increased adhesion in clinical Candida glabrata strains. Mycoses 2018; 61:430-440. [PMID: 29464833 DOI: 10.1111/myc.12756] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 02/13/2018] [Accepted: 02/14/2018] [Indexed: 12/30/2022]
Abstract
Recently, Candida glabrata has emerged as a health-threatening pathogen and the rising resistance to antifungal agent in C. glabrata often leads to clinical treatment failure. To investigate the evolution of drug resistance and adherence ability in four paired clinical isolates collected before and after antifungal treatment. Sequence analysis, gene disruption, drug-susceptibility, adhesion tests and real-time quantitative PCR were performed. The azole-susceptible strains acquired azole resistance after antifungal therapy. Four gain-of-function (GOF) mutations in CgPDR1 were revealed by sequence analysis, namely G1099D, G346D, L344S and P927S, the last being reported for the first time. CDR1, CDR2 and SNQ2 efflux pump gene expression levels were elevated in strains harbouring GOF mutations in CgPDR1, resulting in decreased azole susceptibility. CgPDR1 alleles with distinct GOF mutations displayed different expression profiles for the drug-related genes. CgPDR1GOF mutations led to increased efflux pumps expression levels in a strain background independent way. Hyperactive Pdr1G1099D and Pdr1P927S displayed strain background-dependent increased adherence to host cells via upregulation of EPA1 transcription. Interestingly, the drug transporter gene expression levels did not always correspond with that of the adhesin EPA1 gene. GOF mutations in CgPDR1 conferred drug resistance and increased adherence in the clinical strains, possibly endowing C. glabrata with increased viability and pathogenicity.
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Affiliation(s)
- Qi Ni
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Chen Wang
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yuan Tian
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Danfeng Dong
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Cen Jiang
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Enqiang Mao
- Department of Emergency Intensive Care Unit, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yibing Peng
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
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102
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Construction and Use of a Recyclable Marker To Examine the Role of Major Facilitator Superfamily Protein Members in Candida glabrata Drug Resistance Phenotypes. mSphere 2018; 3:mSphere00099-18. [PMID: 29600281 PMCID: PMC5874441 DOI: 10.1128/msphere.00099-18] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 02/27/2018] [Indexed: 11/27/2022] Open
Abstract
Export of drugs is a problem for chemotherapy of infectious organisms. A class of membrane proteins called the major facilitator superfamily contains a large number of proteins that often elevate drug resistance when overproduced but do not impact this phenotype when the gene is removed. We wondered if this absence of a phenotype for a disruption allele might be due to the redundancy of this group of membrane proteins. We describe the production of an easy-to-use recyclable marker cassette that will allow construction of strains lacking multiple members of the MFS family of transporter proteins. Candida glabrata is the second most common species causing candidiasis. C. glabrata can also readily acquire resistance to azole drugs, complicating its treatment. Here we add to the collection of disruption markers to aid in genetic analysis of this yeast. This new construct is marked with a nourseothricin resistance cassette that produces an estrogen-activated form of Cre recombinase in a methionine-regulated manner. This allows eviction and reuse of this cassette in a facile manner. Using this new disruption marker, we have constructed a series of strains lacking different members of the major facilitator superfamily (MFS) of membrane transporter proteins. The presence of 15 MFS proteins that may contribute to drug resistance in C. glabrata placed a premium on development of a marker that could easily be reused to construct multiple gene-disrupted strains. Employing this recyclable marker, we found that loss of the MFS transporter-encoding gene FLR1 caused a dramatic increase in diamide resistance (as seen before), and deletion of two other MFS-encoding genes did not influence this phenotype. Interestingly, loss of FLR1 led to an increase in levels of oxidized glutathione, suggesting a possible molecular explanation for this enhanced oxidant sensitivity. We also found that while overproduction of the transcription factor Yap1 could suppress the fluconazole sensitivity caused by loss of the important ATP-binding cassette transporter protein Cdr1, this required the presence of FLR1. IMPORTANCE Export of drugs is a problem for chemotherapy of infectious organisms. A class of membrane proteins called the major facilitator superfamily contains a large number of proteins that often elevate drug resistance when overproduced but do not impact this phenotype when the gene is removed. We wondered if this absence of a phenotype for a disruption allele might be due to the redundancy of this group of membrane proteins. We describe the production of an easy-to-use recyclable marker cassette that will allow construction of strains lacking multiple members of the MFS family of transporter proteins.
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103
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Deletion of ADA2 Increases Antifungal Drug Susceptibility and Virulence in Candida glabrata. Antimicrob Agents Chemother 2018; 62:AAC.01924-17. [PMID: 29311082 DOI: 10.1128/aac.01924-17] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 12/15/2017] [Indexed: 12/23/2022] Open
Abstract
Candida glabrata, the second most frequent cause of candidiasis after Candida albicans, is an emerging human fungal pathogen that is intrinsically drug tolerant. Currently, studies of C. glabrata genes involved in drug tolerance are limited. Ada2, a component serving as a transcription adaptor of the Spt-Ada-Gcn5 acetyltransferase (SAGA) complex, is required for antifungal drug tolerance and virulence in C. albicans However, its roles in C. glabrata remain elusive. In this study, we found that ada2 mutants demonstrated severe growth defects at 40°C but only mild defects at 37°C or 25°C. In addition, C. glabrata ada2 mutants exhibited pleiotropic phenotypes, including susceptibility to three classes of antifungal drugs (i.e., azoles, echinocandins, and polyenes) and cell wall-perturbing agents but resistance to the endoplasmic reticulum stressor tunicamycin. According to RNA sequence analysis, the expression of 43 genes was downregulated and the expression of 442 genes was upregulated in the ada2 mutant compared to their expression in the wild type. C. glabrata ADA2, along with its downstream target ERG6, controls antifungal drug tolerance and cell wall integrity. Surprisingly, ada2 mutants were hypervirulent in a murine model of systemic infection, possibly due to the upregulation of multiple adhesin-like genes, increased agar invasion, and overstimulation of murine tumor necrosis factor alpha production.
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104
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Khakhina S, Simonicova L, Moye-Rowley WS. Positive autoregulation and repression of transactivation are key regulatory features of the Candida glabrata Pdr1 transcription factor. Mol Microbiol 2018; 107:747-764. [PMID: 29363861 DOI: 10.1111/mmi.13913] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 01/15/2018] [Accepted: 01/19/2018] [Indexed: 12/23/2022]
Abstract
Resistance to azole drugs, the major clinical antifungal compounds, is most commonly due to gain-of-function (GOF) substitution mutations in a gene called PDR1 in the fungal pathogen Candida glabrata. PDR1 encodes a zinc cluster-containing transcription factor. GOF forms of Pdr1 drive high level expression of downstream target gene expression with accompanying azole resistance. PDR1 has two homologous genes in Saccharomyces cerevisiae, called ScPDR1 and ScPDR3. This study provides evidence that the PDR1 gene in C. glabrata represents a blend of the properties found in the two S. cerevisiae genes. We demonstrated that GOF Pdr1 derivatives are overproduced at the protein level and less stable than the wild-type protein. Overproduction of wild-type Pdr1 increased target gene expression but to a lesser extent than GOF derivatives. Site-directed mutagenesis of Pdr1 binding sites in the PDR1 promoter provided clear demonstration that autoregulation of PDR1 is required for its normal function. An internal deletion mutant of Pdr1 lacking its central regulatory domain behaved as a hyperactive transcription factor that was lethal unless conditionally expressed. A full understanding of the regulation of Pdr1 will provide a new avenue of interfering with azole resistance in C. glabrata.
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Affiliation(s)
- Svetlana Khakhina
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Lucia Simonicova
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - W Scott Moye-Rowley
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
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105
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Giovati L, Santinoli C, Ferrari E, Ciociola T, Martin E, Bandi C, Ricci I, Epis S, Conti S. Candidacidal Activity of a Novel Killer Toxin from Wickerhamomyces anomalus against Fluconazole-Susceptible and -Resistant Strains. Toxins (Basel) 2018; 10:E68. [PMID: 29401638 PMCID: PMC5848169 DOI: 10.3390/toxins10020068] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 01/30/2018] [Accepted: 02/01/2018] [Indexed: 11/16/2022] Open
Abstract
The isolation and characterization from the sand fly Phlebotomus perniciosus of a Wickerhamomyces anomalus yeast strain (Wa1F1) displaying the killer phenotype was recently reported. In the present work, the killer toxin (KT) produced by Wa1F1 was purified and characterized, and its antimicrobial activity in vitro was investigated against fluconazole- susceptible and -resistant clinical isolates and laboratory strains of Candida albicans and C. glabrata displaying known mutations. Wa1F1-KT showed a differential killing ability against different mutant strains of the same species. The results may be useful for the design of therapeutic molecules based on Wa1F1-KT and the study of yeast resistance mechanisms.
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Affiliation(s)
- Laura Giovati
- Department of Medicine and Surgery, University of Parma, 43125 Parma, Italy.
| | - Claudia Santinoli
- Department of Medicine and Surgery, University of Parma, 43125 Parma, Italy.
| | - Elena Ferrari
- Department of Medicine and Surgery, University of Parma, 43125 Parma, Italy.
| | - Tecla Ciociola
- Department of Medicine and Surgery, University of Parma, 43125 Parma, Italy.
| | - Elena Martin
- Department of Biosciences, University of Milan, 20133 Milan, Italy.
| | - Claudio Bandi
- Department of Biosciences, University of Milan, 20133 Milan, Italy.
- Pediatric Clinical Research Center Romeo and Enrica Invernizzi, Ospedale "Luigi Sacco", 20157 Milan, Italy.
| | - Irene Ricci
- School of Biosciences and Veterinary Medicine, University of Camerino, 62032 Camerino, Italy.
| | - Sara Epis
- Department of Biosciences, University of Milan, 20133 Milan, Italy.
- Pediatric Clinical Research Center Romeo and Enrica Invernizzi, Ospedale "Luigi Sacco", 20157 Milan, Italy.
| | - Stefania Conti
- Department of Medicine and Surgery, University of Parma, 43125 Parma, Italy.
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106
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Li L, Liao Z, Yang Y, Lv L, Cao Y, Zhu Z. Metabolomic profiling for the identification of potential biomarkers involved in a laboratory azole resistance in Candida albicans. PLoS One 2018; 13:e0192328. [PMID: 29394282 PMCID: PMC5796700 DOI: 10.1371/journal.pone.0192328] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 01/21/2018] [Indexed: 11/29/2022] Open
Abstract
Candida albicans, one of the most common fungal pathogens, is responsible for several yeast infections in human hosts, being resistant to classically used antifungal drugs, such as azole drugs. Multifactorial and multistep alterations are involved in the azole resistance in Candida albicans. In this study, a FCZ-resistant C. albicans strain was obtained by serial cultures of a FCZ-susceptible C. albicans strain in incrementally increasing concentrations of FCZ. We performed an integrated profile of different classes of molecules related to azole resistance in C. albicans by combining several mass-spectrometry based methodologies. The comparative metabolomic study was performed with the sensitive and resistant strains of C.albicans to identify metabolites altered during the development of resistance to fluconazole, while the intervention strains and non-intervention strains of C.albicans to identify metabolites altered involved in cross-resistant to azole drugs. Our analysis of the different metabolites identified molecules mainly involved in metabolic processes such as amino acid metabolism, tricarboxylic acid cycle and phospholipid metabolism. We also compared the phospholipid composition of each group, revealing that the relative content of phospholipids significantly changed during the development of resistance to azole drugs. According with these results, we hypothesized that the metabolism shift might contribute to azole drugs resistance in C.albicans from multifactorial alterations. Our result paves the way to understand processes underlying the resistance to azole drugs in C. albicans, providing the basis for developing new antifungal drugs.
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Affiliation(s)
- Ling Li
- School of Pharmacy, Second Military Medical University, Shanghai, China
| | - ZeBin Liao
- Department of Radiation Medicine, Faculty of Naval Medicine, Second Military Medical University, Shanghai, China
| | - Yu Yang
- School of Pharmacy, Second Military Medical University, Shanghai, China
| | - Lei Lv
- Department of Pharmacy, Shanghai Eastern Hepatobiliary Surgery Hospital, Shanghai, China
| | - YingYing Cao
- School of Pharmacy, Second Military Medical University, Shanghai, China
- * E-mail: (ZYZ); (YYC)
| | - ZhenYu Zhu
- School of Pharmacy, Second Military Medical University, Shanghai, China
- * E-mail: (ZYZ); (YYC)
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107
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Abstract
Fungal infections have increased significantly in the last few years, and their outcomes are in part complicated by the emergence of antifungal drug-resistant pathogens. Together with Candida species, the mould Aspergillus fumigatus is one of the most prevalent organisms to cause invasive fungal disease. The molecular detection of (tri)azole resistance in both Candida and Aspergillus species may represent a useful means of monitoring the incidence of clinical isolates with antifungal resistance-associated gene alterations. Here, we describe molecular methods that have been developed to allow for accurate detection of azole-resistant isolates among C. glabrata and A. fumigatus fungal species.
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108
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Whaley SG, Caudle KE, Simonicova L, Zhang Q, Moye-Rowley WS, Rogers PD. Jjj1 Is a Negative Regulator of Pdr1-Mediated Fluconazole Resistance in Candida glabrata. mSphere 2018; 3:e00466-17. [PMID: 29507891 PMCID: PMC5821985 DOI: 10.1128/msphere.00466-17] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 01/24/2018] [Indexed: 11/20/2022] Open
Abstract
The high prevalence of fluconazole resistance among clinical isolates of Candida glabrata has greatly hampered the utility of fluconazole for the treatment of invasive candidiasis. Fluconazole resistance in this yeast is almost exclusively due to activating mutations in the transcription factor Pdr1, which result in upregulation of the ABC transporter genes CDR1, PDH1, and SNQ2 and therefore increased fluconazole efflux. However, the regulation of Pdr1 is poorly understood. In order to identify genes that interact with the Pdr1 transcriptional pathway and influence the susceptibility of C. glabrata to fluconazole, we screened a collection of deletion mutants for those exhibiting increased resistance to fluconazole. Deletion of the gene coding for a protein homologous to the Saccharomyces cerevisiae J protein Jjj1 resulted in decreased fluconazole susceptibility. We used the SAT1 flipper method to generate independent deletion mutants for JJJ1 in an SDD clinical isolate. Expression of both CDR1 and PDR1 was increased in the absence of JJJ1. In the absence of CDR1 or PDR1, deletion of JJJ1 has only a modest effect on fluconazole susceptibility. Transcriptional profiling using transcriptome sequencing (RNA-seq) revealed upregulation of genes of the Pdr1 regulon in the absence of JJJ1. Jjj1 appears to be a negative regulator of fluconazole resistance in C. glabrata and acts primarily through upregulation of the ABC transporter gene CDR1 via activation of the Pdr1 transcriptional pathway. IMPORTANCECandida glabrata is the second most common species of Candida recovered from patients with invasive candidiasis. The increasing number of infections due to C. glabrata, combined with its high rates of resistance to the commonly used, well-tolerated azole class of antifungal agents, has limited the use of this antifungal class. This has led to the preferential use of echinocandins as empirical treatment for serious Candida infections. The primary mechanism of resistance found in clinical isolates is the presence of an activating mutation in the gene encoding the transcription factor Pdr1 that results in upregulation of one or more of the efflux pumps Cdr1, Pdh1, and Snq2. By developing a better understanding of this mechanism of resistance to the azoles, it will be possible to develop strategies for reclaiming the utility of the azole antifungals against this important fungal pathogen.
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Affiliation(s)
- Sarah G. Whaley
- Department of Clinical Pharmacy, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Kelly E. Caudle
- Department of Clinical Pharmacy, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Lucia Simonicova
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Qing Zhang
- Department of Clinical Pharmacy, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - W. Scott Moye-Rowley
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - P. David Rogers
- Department of Clinical Pharmacy, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, USA
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109
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Verma S, Shakya VPS, Idnurm A. Exploring and exploiting the connection between mitochondria and the virulence of human pathogenic fungi. Virulence 2018; 9:426-446. [PMID: 29261004 PMCID: PMC5955198 DOI: 10.1080/21505594.2017.1414133] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 12/04/2017] [Accepted: 12/04/2017] [Indexed: 12/17/2022] Open
Abstract
Mitochondria are best known for their role in the production of ATP; however, recent research implicates other mitochondrial functions in the virulence of human pathogenic fungi. Inhibitors of mitochondrial succinate dehydrogenase or the electron transport chain are successfully used to combat plant pathogenic fungi, but similar inhibition of mitochondrial functions has not been pursued for applications in medical mycology. Advances in understanding mitochondrial function relevant to human pathogenic fungi are in four major directions: 1) the role of mitochondrial morphology in virulence, 2) mitochondrial genetics, with a focus on mitochondrial DNA recombination and mitochondrial inheritance 3) the role of mitochondria in drug resistance, and 4) the interaction of mitochondria with other organelles. Collectively, despite the similarities in mitochondrial functions between fungi and animals, this organelle is currently an under-explored potential target to treat medical mycoses. Future research could define and then exploit those mitochondrial components best suited as drug targets.
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Affiliation(s)
- Surbhi Verma
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Viplendra P. S. Shakya
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Alexander Idnurm
- School of BioSciences, University of Melbourne, Parkville, VIC, Australia
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110
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Biswas C, Chen SCA, Halliday C, Martinez E, Rockett RJ, Wang Q, Timms VJ, Dhakal R, Sadsad R, Kennedy KJ, Playford G, Marriott DJ, Slavin MA, Sorrell TC, Sintchenko V. Whole Genome Sequencing of Candida glabrata for Detection of Markers of Antifungal Drug Resistance. J Vis Exp 2017. [PMID: 29364212 DOI: 10.3791/56714] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Candida glabrata can rapidly acquire mutations that result in drug resistance, especially to azoles and echinocandins. Identification of genetic mutations is essential, as resistance detected in vitro can often be correlated with clinical failure. We examined the feasibility of using whole genome sequencing (WGS) for genome-wide analysis of antifungal drug resistance in C. glabrata. The aim was torecognize enablers and barriers in the implementation WGS and measure its effectiveness. This paper outlines the key quality control checkpoints and essential components of WGS methodology to investigate genetic markers associated with reduced susceptibility to antifungal agents. It also estimates the accuracy of data analysis and turn-around-time of testing. Phenotypic susceptibility of 12 clinical, and one ATCC strain of C. glabrata was determined through antifungal susceptibility testing. These included three isolate pairs, from three patients, that developed rise in drug minimum inhibitory concentrations. In two pairs, the second isolate of each pair developed resistance to echinocandins. The second isolate of the third pair developed resistance to 5-flucytosine. The remaining comprised of susceptible and azole resistant isolates. Single nucleotide polymorphisms (SNPs) in genes linked to echinocandin, azole and 5-flucytosine resistance were confirmed in resistant isolates through WGS using the next generation sequencing. Non-synonymous SNPs in antifungal resistance genes such as FKS1, FKS2, CgPDR1, CgCDR1 and FCY2 were identified. Overall, an average of 98% of the WGS reads of C. glabrata isolates mapped to the reference genome with about 75-fold read depth coverage. The turnaround time and cost were comparable to Sanger sequencing. In conclusion, WGS of C. glabrata was feasible in revealing clinically significant gene mutations involved in resistance to different antifungal drug classes without the need for multiple PCR/DNA sequencing reactions. This represents a positive step towards establishing WGS capability in the clinical laboratory for simultaneous detection of antifungal resistance conferring substitutions.
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Affiliation(s)
- Chayanika Biswas
- Centre for Infectious Diseases and Microbiology-Public Health, Westmead Hospital;
| | - Sharon C-A Chen
- Centre for Infectious Diseases and Microbiology-Public Health, Westmead Hospital; Centre for Infectious Diseases and Microbiology Laboratory Services, ICPMR; Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney
| | - Catriona Halliday
- Centre for Infectious Diseases and Microbiology-Public Health, Westmead Hospital; Centre for Infectious Diseases and Microbiology Laboratory Services, ICPMR
| | - Elena Martinez
- Centre for Infectious Diseases and Microbiology-Public Health, Westmead Hospital
| | - Rebecca J Rockett
- Centre for Infectious Diseases and Microbiology-Public Health, Westmead Hospital
| | - Qinning Wang
- Centre for Infectious Diseases and Microbiology-Public Health, Westmead Hospital
| | - Verlaine J Timms
- Centre for Infectious Diseases and Microbiology-Public Health, Westmead Hospital
| | - Rajat Dhakal
- Centre for Infectious Diseases and Microbiology-Public Health, Westmead Hospital
| | - Rosemarie Sadsad
- Centre for Infectious Diseases and Microbiology-Public Health, Westmead Hospital
| | - Karina J Kennedy
- Department of Microbiology and Infectious Diseases, Canberra Hospital and Health Services, Australian National University Medical School
| | - Geoffrey Playford
- Department of Microbiology and Infectious Diseases, Canberra Hospital and Health Services, Australian National University Medical School; Infection Management Services, Australian National University Medical School
| | - Deborah J Marriott
- Department of Microbiology and Infectious Diseases, St. Vincent's Hospital
| | - Monica A Slavin
- Department of Infectious Diseases, Peter MacCallum Cancer Centre
| | - Tania C Sorrell
- Centre for Infectious Diseases and Microbiology-Public Health, Westmead Hospital; Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney
| | - Vitali Sintchenko
- Centre for Infectious Diseases and Microbiology-Public Health, Westmead Hospital; Centre for Infectious Diseases and Microbiology Laboratory Services, ICPMR; Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney
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111
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Wertheimer NB, Stone N, Berman J. Ploidy dynamics and evolvability in fungi. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0461. [PMID: 28080987 PMCID: PMC5095540 DOI: 10.1098/rstb.2015.0461] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/01/2016] [Indexed: 12/12/2022] Open
Abstract
Rapid responses to acute stresses are essential for stress survival and are critical to the ability of fungal pathogens to adapt to new environments or hosts. The rapid emergence of drug resistance is used as a model for how fungi adapt and survive stress conditions that inhibit the growth of progenitor cells. Aneuploidy and loss of heterozygosity (LOH), which are large-scale genome shifts involving whole chromosomes or chromosome arms, occur at higher frequency than point mutations and have the potential to mediate stress survival. Furthermore, the stress of exposure to an antifungal drug can induce elevated levels of LOH and can promote the formation of aneuploids. This occurs via mitotic defects that first produce tetraploid progeny with extra spindles, followed by chromosome mis-segregation. Thus, drug exposure induces elevated levels of aneuploidy, which can alter the copy number of genes that improve survival in a given stress or drug. Selection then acts to increase the proportion of adaptive aneuploids in the population. Because aneuploidy is a common property of many pathogenic fungi, including those posing emerging threats to plants, animals and humans, we propose that aneuploid formation and LOH often accompanying it contribute to the rapid generation of diversity that can facilitate the emergence of fungal pathogens to new environmental niches and/or new hosts, as well as promote antifungal drug resistance that makes emerging fungal infections ever more difficult to contain.This article is part of the themed issue 'Tackling emerging fungal threats to animal health, food security and ecosystem resilience'.
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Affiliation(s)
- Noa Blutraich Wertheimer
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Britannia 418, Ramat Aviv, Israel
| | - Neil Stone
- Institute of Infection and Immunity, St George's, University of London, London SW17 0RE, UK
| | - Judith Berman
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Britannia 418, Ramat Aviv, Israel
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112
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Sharma C, Chowdhary A. Molecular bases of antifungal resistance in filamentous fungi. Int J Antimicrob Agents 2017; 50:607-616. [DOI: 10.1016/j.ijantimicag.2017.06.018] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2016] [Revised: 06/16/2017] [Accepted: 06/24/2017] [Indexed: 01/15/2023]
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113
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Kodedová M, Sychrová H. Synthetic antimicrobial peptides of the halictines family disturb the membrane integrity of Candida cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:1851-1858. [DOI: 10.1016/j.bbamem.2017.06.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 05/19/2017] [Accepted: 06/05/2017] [Indexed: 12/31/2022]
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114
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Perlin DS, Wiederhold NP. Culture-Independent Molecular Methods for Detection of Antifungal Resistance Mechanisms and Fungal Identification. J Infect Dis 2017; 216:S458-S465. [PMID: 28911041 DOI: 10.1093/infdis/jix121] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Resistance to azoles and echinocandins has emerged as a significant factor affecting the clinical management of patients with invasive fungal infections. Immunosuppressed patients at high risk for invasive fungal infections often have prolonged or repeated exposure to antifungals resulting in either the well-documented selection of naturally occurring, less susceptible fungal species, or the in situ development of specific resistance mechanisms. Nucleic acid-based molecular diagnostics are particularly well suited for the rapid detection of low-abundance fungal pathogens and identification of the infecting pathogen to the genus and species levels, as well as assessment of resistance mechanisms. A wide range of molecular probing technologies involving real-time polymerase chain reaction (PCR) assays that facilitate direct analysis of a single infecting genome in a sterile blood specimen are available and have recently been commercialized (eg, Roche LightCycler SeptiFast and T2 Biosystems T2Candida). One of the exciting applications of molecular technology is the direct detection of specific resistance mechanisms that evolve during therapy. In principle, the detection of resistance mechanisms that have been independently validated to cause resistance provides a culture-independent biomarker for potential therapeutic failure. The emergence of real-time PCR assays utilizing allele-specific molecular detection technology that is highly sensitive, robust, and high-throughput has the potential to improve patient care by providing faster detection of drug-resistant infecting strains and to help inform therapeutic management.
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Affiliation(s)
- David S Perlin
- Public Health Research Institute, Rutgers Biomedical and Health Sciences, Newark, New Jersey
| | - Nathan P Wiederhold
- Fungus Testing Laboratory, University of Texas Health Science Center, San Antonio
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115
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Arendrup MC, Patterson TF. Multidrug-Resistant Candida: Epidemiology, Molecular Mechanisms, and Treatment. J Infect Dis 2017; 216:S445-S451. [PMID: 28911043 DOI: 10.1093/infdis/jix131] [Citation(s) in RCA: 377] [Impact Index Per Article: 53.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Invasive Candida infections remain an important cause of morbidity and mortality, especially in hospitalized and immunocompromised or critically ill patients. A limited number of antifungal agents from only a few drug classes are available to treat patients with these serious infections. Resistance can be either intrinsic or acquired. Resistance mechanisms are not exchanged between Candida; thus, acquired resistance either emerges in response to an antifungal selection pressure in the individual patient or, more rarely, occur due to horizontal transmission of resistant strains between patients. Although multidrug resistance is uncommon, increasing reports of multidrug resistance to the azoles, echinocandins, and polyenes have occurred in several Candida species, most notably Candida glabrata and more recently Candida auris. Drivers are overall antifungal use, subtherapeutic drug levels at sites of infection/colonization, drug sequestration in the biofilm matrix, and, in the setting of outbreaks, suboptimal infection control. Moreover, recent research suggests that DNA mismatch repair gene mutations may facilitate acquisition of resistance mutations in C. glabrata specifically. Diagnosis of antifungal-resistant Candida infections is critical to the successful management of patients with these infections. Reduction of unnecessary use of antifungals via antifungal stewardship is critical to limit multidrug resistance emergence.
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Affiliation(s)
- Maiken Cavling Arendrup
- Unit of Mycology, Statens Serum Institut.,Department of Clinical Microbiology, Rigshospitalet.,Department of Clinical Medicine, University of Copenhagen, Denmark
| | - Thomas F Patterson
- Division of Infectious Diseases, San Antonio Center for Medical Mycology, UT Health San Antonio, and the South Texas Veterans Health Care System
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116
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Vitenshtein A, Charpak-Amikam Y, Yamin R, Bauman Y, Isaacson B, Stein N, Berhani O, Dassa L, Gamliel M, Gur C, Glasner A, Gomez C, Ben-Ami R, Osherov N, Cormack BP, Mandelboim O. NK Cell Recognition of Candida glabrata through Binding of NKp46 and NCR1 to Fungal Ligands Epa1, Epa6, and Epa7. Cell Host Microbe 2017; 20:527-534. [PMID: 27736647 DOI: 10.1016/j.chom.2016.09.008] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 08/10/2016] [Accepted: 09/21/2016] [Indexed: 10/20/2022]
Abstract
Natural killer (NK) cells form an important arm of the innate immune system and function to combat a wide range of invading pathogens, ranging from viruses to bacteria. However, the means by which NK cells accomplish recognition of pathogens with a limited repertoire of receptors remain largely unknown. In the current study, we describe the recognition of an emerging fungal pathogen, Candida glabrata, by the human NK cytotoxic receptor NKp46 and its mouse ortholog, NCR1. Using NCR1 knockout mice, we observed that this receptor-mediated recognition was crucial for controlling C. glabrata infection in vitro and in vivo. Finally, we delineated the fungal ligands to be the C. glabrata adhesins Epa1, Epa6, and Epa7 and demonstrated that clearance of systemic C. glabrata infections in vivo depends on their recognition by NCR1. As NKp46 and NCR1 have been previously shown to bind viral adhesion receptors, we speculate that NKp46/NCR1 may be a novel type of pattern recognition receptor.
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Affiliation(s)
- Alon Vitenshtein
- The Lautenberg Center for General and Tumor Immunology, The BioMedical Research Institute Israel Canada of the Faculty of Medicine (IMRIC), The Hebrew University Hadassah Medical School, 91120 Jerusalem, Israel
| | - Yoav Charpak-Amikam
- The Lautenberg Center for General and Tumor Immunology, The BioMedical Research Institute Israel Canada of the Faculty of Medicine (IMRIC), The Hebrew University Hadassah Medical School, 91120 Jerusalem, Israel
| | - Rachel Yamin
- The Lautenberg Center for General and Tumor Immunology, The BioMedical Research Institute Israel Canada of the Faculty of Medicine (IMRIC), The Hebrew University Hadassah Medical School, 91120 Jerusalem, Israel
| | - Yoav Bauman
- The Lautenberg Center for General and Tumor Immunology, The BioMedical Research Institute Israel Canada of the Faculty of Medicine (IMRIC), The Hebrew University Hadassah Medical School, 91120 Jerusalem, Israel
| | - Batya Isaacson
- The Lautenberg Center for General and Tumor Immunology, The BioMedical Research Institute Israel Canada of the Faculty of Medicine (IMRIC), The Hebrew University Hadassah Medical School, 91120 Jerusalem, Israel
| | - Natan Stein
- The Lautenberg Center for General and Tumor Immunology, The BioMedical Research Institute Israel Canada of the Faculty of Medicine (IMRIC), The Hebrew University Hadassah Medical School, 91120 Jerusalem, Israel
| | - Orit Berhani
- The Lautenberg Center for General and Tumor Immunology, The BioMedical Research Institute Israel Canada of the Faculty of Medicine (IMRIC), The Hebrew University Hadassah Medical School, 91120 Jerusalem, Israel
| | - Liat Dassa
- The Lautenberg Center for General and Tumor Immunology, The BioMedical Research Institute Israel Canada of the Faculty of Medicine (IMRIC), The Hebrew University Hadassah Medical School, 91120 Jerusalem, Israel
| | - Moriya Gamliel
- The Lautenberg Center for General and Tumor Immunology, The BioMedical Research Institute Israel Canada of the Faculty of Medicine (IMRIC), The Hebrew University Hadassah Medical School, 91120 Jerusalem, Israel
| | - Chamutal Gur
- The Lautenberg Center for General and Tumor Immunology, The BioMedical Research Institute Israel Canada of the Faculty of Medicine (IMRIC), The Hebrew University Hadassah Medical School, 91120 Jerusalem, Israel
| | - Ariella Glasner
- The Lautenberg Center for General and Tumor Immunology, The BioMedical Research Institute Israel Canada of the Faculty of Medicine (IMRIC), The Hebrew University Hadassah Medical School, 91120 Jerusalem, Israel
| | - Carlos Gomez
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ronen Ben-Ami
- Infectious Diseases Unit, Tel Aviv Sourasky Medical Center, 6423906 Tel Aviv, Israel; Sackler School of Medicine, Tel Aviv University, 39040 Tel Aviv, Israel
| | - Nir Osherov
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, 39040 Tel Aviv, Israel
| | - Brendan P Cormack
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Ofer Mandelboim
- The Lautenberg Center for General and Tumor Immunology, The BioMedical Research Institute Israel Canada of the Faculty of Medicine (IMRIC), The Hebrew University Hadassah Medical School, 91120 Jerusalem, Israel.
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117
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Vale-Silva L, Beaudoing E, Tran VDT, Sanglard D. Comparative Genomics of Two Sequential Candida glabrata Clinical Isolates. G3 (BETHESDA, MD.) 2017; 7:2413-2426. [PMID: 28663342 PMCID: PMC5555451 DOI: 10.1534/g3.117.042887] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Accepted: 06/26/2017] [Indexed: 01/14/2023]
Abstract
Candida glabrata is an important fungal pathogen which develops rapid antifungal resistance in treated patients. It is known that azole treatments lead to antifungal resistance in this fungal species and that multidrug efflux transporters are involved in this process. Specific mutations in the transcriptional regulator PDR1 result in upregulation of the transporters. In addition, we showed that the PDR1 mutations can contribute to enhance virulence in animal models. In this study, we were interested to compare genomes of two specific C. glabrata-related isolates, one of which was azole susceptible (DSY562) while the other was azole resistant (DSY565). DSY565 contained a PDR1 mutation (L280F) and was isolated after a time-lapse of 50 d of azole therapy. We expected that genome comparisons between both isolates could reveal additional mutations reflecting host adaptation or even additional resistance mechanisms. The PacBio technology used here yielded 14 major contigs (sizes 0.18-1.6 Mb) and mitochondrial genomes from both DSY562 and DSY565 isolates that were highly similar to each other. Comparisons of the clinical genomes with the published CBS138 genome indicated important genome rearrangements, but not between the clinical strains. Among the unique features, several retrotransposons were identified in the genomes of the investigated clinical isolates. DSY562 and DSY565 each contained a large set of adhesin-like genes (101 and 107, respectively), which exceed by far the number of reported adhesins (63) in the CBS138 genome. Comparison between DSY562 and DSY565 yielded 17 nonsynonymous SNPs (among which the was the expected PDR1 mutation) as well as small size indels in coding regions (11) but mainly in adhesin-like genes. The genomes contained a DNA mismatch repair allele of MSH2 known to be involved in the so-called hyper-mutator phenotype of this yeast species and the number of accumulated mutations between both clinical isolates is consistent with the presence of a MSH2 defect. In conclusion, this study is the first to compare genomes of C. glabrata sequential clinical isolates using the PacBio technology as an approach. The genomes of these isolates taken in the same patient at two different time points exhibited limited variations, even if submitted to the host pressure.
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Affiliation(s)
- Luis Vale-Silva
- Institute of Microbiology, University of Lausanne, CH-1011, Switzerland
- Lausanne University Hospital, CH-1011, Switzerland
| | - Emmanuel Beaudoing
- Center for Integrative Genomics, Lausanne Genomic Technologies Facility, CH-1015, Switzerland
| | - Van Du T Tran
- Vital-IT Group, SIB Swiss Institute of Bioinformatics, CH-1015 Lausanne, Switzerland
| | - Dominique Sanglard
- Institute of Microbiology, University of Lausanne, CH-1011, Switzerland
- Lausanne University Hospital, CH-1011, Switzerland
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118
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Berkow EL, Lockhart SR. Fluconazole resistance in Candida species: a current perspective. Infect Drug Resist 2017; 10:237-245. [PMID: 28814889 PMCID: PMC5546770 DOI: 10.2147/idr.s118892] [Citation(s) in RCA: 288] [Impact Index Per Article: 41.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Candida albicans and the emerging non-albicans Candida spp. have significant clinical relevance among many patient populations. Current treatment guidelines include fluconazole as a primary therapeutic option for the treatment of these infections, but it is only fungistatic against Candida spp. and both inherent and acquired resistance to fluconazole have been reported. Such mechanisms of resistance include increased drug efflux, alteration or increase in the drug target, and development of compensatory pathways for producing the target sterol, ergosterol. While many mechanisms of resistance observed in C. albicans are also found in the non-albicans species, there are also important and unexpected differences between species. Furthermore, mechanisms of fluconazole resistance in emerging Candida spp., including the global health threat Candida auris, are largely unknown. In order to preserve the utility of one of our fundamental antifungal drugs, fluconazole, it is essential that we fully appreciate the manner by which Candida spp. manifest resistance to it.
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Affiliation(s)
- Elizabeth L Berkow
- Mycotic Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Shawn R Lockhart
- Mycotic Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
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119
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Competitive Fitness of Fluconazole-Resistant Clinical Candida albicans Strains. Antimicrob Agents Chemother 2017; 61:AAC.00584-17. [PMID: 28461316 DOI: 10.1128/aac.00584-17] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 04/23/2017] [Indexed: 12/27/2022] Open
Abstract
The pathogenic yeast Candida albicans can develop resistance to the widely used antifungal agent fluconazole, which inhibits ergosterol biosynthesis. Resistance is often caused by gain-of-function mutations in the transcription factors Mrr1 and Tac1, which result in constitutive overexpression of multidrug efflux pumps, and Upc2, which result in constitutive overexpression of ergosterol biosynthesis genes. However, the deregulated gene expression that is caused by hyperactive forms of these transcription factors also reduces the fitness of the cells in the absence of the drug. To investigate whether fluconazole-resistant clinical C. albicans isolates have overcome the fitness costs of drug resistance, we assessed the relative fitness of C. albicans isolates containing resistance mutations in these transcription factors in competition with matched drug-susceptible isolates from the same patients. Most of the fluconazole-resistant isolates were outcompeted by the corresponding drug-susceptible isolates when grown in rich medium without fluconazole. On the other hand, some resistant isolates with gain-of-function mutations in MRR1 did not exhibit reduced fitness under these conditions. In a mouse model of disseminated candidiasis, three out of four tested fluconazole-resistant clinical isolates did not exhibit a significant fitness defect. However, all four fluconazole-resistant isolates were outcompeted by the matched susceptible isolates in a mouse model of gastrointestinal colonization, demonstrating that the effects of drug resistance on in vivo fitness depend on the host niche. Collectively, our results indicate that the fitness costs of drug resistance in C. albicans are not easily remediated, especially when proper control of gene expression is required for successful adaptation to life within a mammalian host.
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120
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Biswas C, Chen SCA, Halliday C, Kennedy K, Playford EG, Marriott DJ, Slavin MA, Sorrell TC, Sintchenko V. Identification of genetic markers of resistance to echinocandins, azoles and 5-fluorocytosine in Candida glabrata by next-generation sequencing: a feasibility study. Clin Microbiol Infect 2017; 23:676.e7-676.e10. [PMID: 28344162 DOI: 10.1016/j.cmi.2017.03.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 03/03/2017] [Accepted: 03/18/2017] [Indexed: 01/05/2023]
Abstract
OBJECTIVES Multi-antifungal drug resistance in Candida glabrata is increasing. We examined the feasibility of next-generation sequencing (NGS) to investigate the presence of antifungal drug resistance markers in C. glabrata. METHODS The antifungal susceptibility of 12 clinical isolates and one ATCC strain of C. glabrata was determined using the Sensititre YeastOne® YO10 assay. These included three isolate pairs where the second isolate of each pair had developed a rise in drug MICs. Single nucleotide polymorphisms (SNPs) in genes known to be linked to echinocandin, azole and 5-fluorocytosine resistance were analysed in all isolates through NGS. RESULTS High-quality non-synonymous SNPs in antifungal resistance genes such as FKS1, FKS2, CgCDR1, CgPDR1 and FCY2 were identified. For two of three isolate pairs, there was a >60-fold rise in MICs to all echinocandins in the second isolate from each pair; one echinocandin-resistant isolate harboured a mutation in FKS1 (S629P) and the other in FKS2 (S663P). Of the third pair, both the 5-fluorocytosine-susceptible, and resistant isolates had a mutation in FCY2 (A237T). SNPs in CgPDR1 were found in pan-azole-resistant isolates. SNPs in other genes linked to azole resistance (CgCDR1, ERG9 and CgFLR1) were present in both azole-susceptible and azole-resistant isolates. SNPs were also identified in Candida adhesin genes EPA1, EPA6, PWP2 and PWP5 but their presence was not associated with higher drug MICs. CONCLUSIONS Genome-wide analysis of antifungal resistance markers was feasible and simultaneously revealed mutation patterns of genes implicated in resistance to different antifungal drug classes.
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Affiliation(s)
- C Biswas
- Centre for Infectious Diseases and Microbiology Laboratory Services, Westmead Hospital, Sydney, Australia; Centre for Infectious Diseases and Microbiology-Public Health, Westmead Hospital, Sydney, Australia.
| | - S C-A Chen
- Centre for Infectious Diseases and Microbiology Laboratory Services, Westmead Hospital, Sydney, Australia; Centre for Infectious Diseases and Microbiology-Public Health, Westmead Hospital, Sydney, Australia; Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, Sydney, Australia
| | - C Halliday
- Centre for Infectious Diseases and Microbiology Laboratory Services, Westmead Hospital, Sydney, Australia
| | - K Kennedy
- Department of Infectious Diseases and Microbiology, Canberra Hospital, Australian National University Medical School, Canberra, Australia
| | - E G Playford
- Infection Management Services, Princess Alexandra Hospital, Brisbane, Australia
| | - D J Marriott
- Department of Microbiology and Infectious Diseases, St Vincent's Hospital, Sydney, Australia
| | - M A Slavin
- Department of Infectious Diseases, Peter MacCallum Cancer Centre, Melbourne, Australia
| | - T C Sorrell
- Centre for Infectious Diseases and Microbiology-Public Health, Westmead Hospital, Sydney, Australia; Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, Sydney, Australia
| | - V Sintchenko
- Centre for Infectious Diseases and Microbiology Laboratory Services, Westmead Hospital, Sydney, Australia; Centre for Infectious Diseases and Microbiology-Public Health, Westmead Hospital, Sydney, Australia; Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, Sydney, Australia
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121
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Rodrigues CF, Rodrigues ME, Silva S, Henriques M. Candida glabrata Biofilms: How Far Have We Come? J Fungi (Basel) 2017; 3:E11. [PMID: 29371530 PMCID: PMC5715960 DOI: 10.3390/jof3010011] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 02/07/2017] [Accepted: 02/16/2017] [Indexed: 11/25/2022] Open
Abstract
Infections caused by Candida species have been increasing in the last decades and can result in local or systemic infections, with high morbidity and mortality. After Candida albicans, Candida glabrata is one of the most prevalent pathogenic fungi in humans. In addition to the high antifungal drugs resistance and inability to form hyphae or secret hydrolases, C. glabrata retain many virulence factors that contribute to its extreme aggressiveness and result in a low therapeutic response and serious recurrent candidiasis, particularly biofilm formation ability. For their extraordinary organization, especially regarding the complex structure of the matrix, biofilms are very resistant to antifungal treatments. Thus, new approaches to the treatment of C. glabrata's biofilms are emerging. In this article, the knowledge available on C. glabrata's resistance will be highlighted, with a special focus on biofilms, as well as new therapeutic alternatives to control them.
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Affiliation(s)
- Célia F Rodrigues
- CEB, Centre of Biological Engineering, LIBRO-Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, 4710-057 Braga, Portugal.
| | - Maria Elisa Rodrigues
- CEB, Centre of Biological Engineering, LIBRO-Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, 4710-057 Braga, Portugal.
| | - Sónia Silva
- CEB, Centre of Biological Engineering, LIBRO-Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, 4710-057 Braga, Portugal.
| | - Mariana Henriques
- CEB, Centre of Biological Engineering, LIBRO-Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, 4710-057 Braga, Portugal.
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122
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Whaley SG, Berkow EL, Rybak JM, Nishimoto AT, Barker KS, Rogers PD. Azole Antifungal Resistance in Candida albicans and Emerging Non- albicans Candida Species. Front Microbiol 2017; 7:2173. [PMID: 28127295 PMCID: PMC5226953 DOI: 10.3389/fmicb.2016.02173] [Citation(s) in RCA: 410] [Impact Index Per Article: 58.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 12/28/2016] [Indexed: 12/15/2022] Open
Abstract
Within the limited antifungal armamentarium, the azole antifungals are the most frequent class used to treat Candida infections. Azole antifungals such as fluconazole are often preferred treatment for many Candida infections as they are inexpensive, exhibit limited toxicity, and are available for oral administration. There is, however, extensive documentation of intrinsic and developed resistance to azole antifungals among several Candida species. As the frequency of azole resistant Candida isolates in the clinical setting increases, it is essential to elucidate the mechanisms of such resistance in order to both preserve and improve upon the azole class of antifungals for the treatment of Candida infections. This review examines azole resistance in infections caused by C. albicans as well as the emerging non-albicans Candida species C. parapsilosis, C. tropicalis, C. krusei, and C. glabrata and in particular, describes the current understanding of molecular basis of azole resistance in these fungal species.
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Affiliation(s)
- Sarah G Whaley
- Department of Clinical Pharmacy, College of Pharmacy, University of Tennessee Health Science Center Memphis, TN, USA
| | - Elizabeth L Berkow
- Department of Clinical Pharmacy, College of Pharmacy, University of Tennessee Health Science Center Memphis, TN, USA
| | - Jeffrey M Rybak
- Department of Clinical Pharmacy, College of Pharmacy, University of Tennessee Health Science Center Memphis, TN, USA
| | - Andrew T Nishimoto
- Department of Clinical Pharmacy, College of Pharmacy, University of Tennessee Health Science Center Memphis, TN, USA
| | - Katherine S Barker
- Department of Clinical Pharmacy, College of Pharmacy, University of Tennessee Health Science Center Memphis, TN, USA
| | - P David Rogers
- Department of Clinical Pharmacy, College of Pharmacy, University of Tennessee Health Science CenterMemphis, TN, USA; Center for Pediatric Pharmacokinetics and Therapeutics, University of Tennessee Health Science CenterMemphis, TN, USA
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123
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Hagiwara D, Miura D, Shimizu K, Paul S, Ohba A, Gonoi T, Watanabe A, Kamei K, Shintani T, Moye-Rowley WS, Kawamoto S, Gomi K. A Novel Zn2-Cys6 Transcription Factor AtrR Plays a Key Role in an Azole Resistance Mechanism of Aspergillus fumigatus by Co-regulating cyp51A and cdr1B Expressions. PLoS Pathog 2017; 13:e1006096. [PMID: 28052140 PMCID: PMC5215518 DOI: 10.1371/journal.ppat.1006096] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 11/28/2016] [Indexed: 02/08/2023] Open
Abstract
Successful treatment of aspergillosis caused by Aspergillus fumigatus is threatened by an increasing incidence of drug resistance. This situation is further complicated by the finding that strains resistant to azoles, the major antifungal drugs for aspergillosis, have been widely disseminated across the globe. To elucidate mechanisms underlying azole resistance, we identified a novel transcription factor that is required for normal azole resistance in Aspergillus fungi including A. fumigatus, Aspergillus oryzae, and Aspergillus nidulans. This fungal-specific Zn2-Cys6 type transcription factor AtrR was found to regulate expression of the genes related to ergosterol biosynthesis, including cyp51A that encodes a target protein of azoles. The atrR deletion mutant showed impaired growth under hypoxic conditions and attenuation of virulence in murine infection model for aspergillosis. These results were similar to the phenotypes for a mutant strain lacking SrbA that is also a direct regulator for the cyp51A gene. Notably, AtrR was responsible for the expression of cdr1B that encodes an ABC transporter related to azole resistance, whereas SrbA was not involved in the regulation. Chromatin immunoprecipitation assays indicated that AtrR directly bound both the cyp51A and cdr1B promoters. In the clinically isolated itraconazole resistant strain that harbors a mutant Cyp51A (G54E), deletion of the atrR gene resulted in a hypersensitivity to the azole drugs. Together, our results revealed that AtrR plays a pivotal role in a novel azole resistance mechanism by co-regulating the drug target (Cyp51A) and putative drug efflux pump (Cdr1B).
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Affiliation(s)
- Daisuke Hagiwara
- Medical Mycology Research Center, Chiba University, Chiba, Japan
- * E-mail: (DH); (KG)
| | - Daisuke Miura
- Department of Bioindustrial Informatics and Genomics, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Kiminori Shimizu
- Medical Mycology Research Center, Chiba University, Chiba, Japan
| | - Sanjoy Paul
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Ayumi Ohba
- Department of Bioindustrial Informatics and Genomics, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Tohru Gonoi
- Medical Mycology Research Center, Chiba University, Chiba, Japan
| | - Akira Watanabe
- Medical Mycology Research Center, Chiba University, Chiba, Japan
| | - Katsuhiko Kamei
- Medical Mycology Research Center, Chiba University, Chiba, Japan
| | - Takahiro Shintani
- Department of Bioindustrial Informatics and Genomics, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - W. Scott Moye-Rowley
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Susumu Kawamoto
- Medical Mycology Research Center, Chiba University, Chiba, Japan
| | - Katsuya Gomi
- Department of Bioindustrial Informatics and Genomics, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
- * E-mail: (DH); (KG)
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Toth Hervay N, Konecna A, Balazfyova Z, Svrbicka A, Gbelska Y. Insight into the Kluyveromyces lactis Pdr1p regulon. Can J Microbiol 2016; 62:918-931. [PMID: 27556366 DOI: 10.1139/cjm-2016-0220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The overexpression of efflux pumps is an important mechanism leading to the development of multidrug resistance phenomenon. The transcription factor KlPdr1p, belonging to the Zn2Cys6 family, is a central regulator of efflux pump expression in Kluyveromyces lactis. To better understand how KlPDR1-mediated drug resistance is achieved in K. lactis, we used DNA microarrays to identify genes whose expression was affected by deletion or overexpression of the KlPDR1 gene. Eighty-nine targets of the KlPDR1 were identified. From those the transcription of 16 genes was induced in the transformant overexpressing KlPDR1* and simultaneously repressed in the Klpdr1Δ deletion mutant. Almost all of these genes contain putative binding motifs for the AP-1-like transcription factors in their promoters. Furthermore, we studied the possible interplay between KlPdr1p and KlYap1p transcription factors. Our results show that KlYap1p does not significantly contribute to the regulation of KlPDR1 gene expression in the presence of azoles. However, KlPDR1 expression markedly increased in the presence of hydrogen peroxide and hinged upon the presence of KlYap1p. Our results show that although both KlPdr1p and KlYap1p transcription factors are involved in the control of K. lactis multidrug resistance, further studies will be needed to determine their interplay.
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Affiliation(s)
- Nora Toth Hervay
- Comenius University in Bratislava, Faculty of Natural Sciences, Department of Microbiology and Virology, Ilkovicova 6, Mlynska dolina, 842 15 Bratislava, Slovak Republic.,Comenius University in Bratislava, Faculty of Natural Sciences, Department of Microbiology and Virology, Ilkovicova 6, Mlynska dolina, 842 15 Bratislava, Slovak Republic
| | - Alexandra Konecna
- Comenius University in Bratislava, Faculty of Natural Sciences, Department of Microbiology and Virology, Ilkovicova 6, Mlynska dolina, 842 15 Bratislava, Slovak Republic.,Comenius University in Bratislava, Faculty of Natural Sciences, Department of Microbiology and Virology, Ilkovicova 6, Mlynska dolina, 842 15 Bratislava, Slovak Republic
| | - Zuzana Balazfyova
- Comenius University in Bratislava, Faculty of Natural Sciences, Department of Microbiology and Virology, Ilkovicova 6, Mlynska dolina, 842 15 Bratislava, Slovak Republic.,Comenius University in Bratislava, Faculty of Natural Sciences, Department of Microbiology and Virology, Ilkovicova 6, Mlynska dolina, 842 15 Bratislava, Slovak Republic
| | - Alexandra Svrbicka
- Comenius University in Bratislava, Faculty of Natural Sciences, Department of Microbiology and Virology, Ilkovicova 6, Mlynska dolina, 842 15 Bratislava, Slovak Republic.,Comenius University in Bratislava, Faculty of Natural Sciences, Department of Microbiology and Virology, Ilkovicova 6, Mlynska dolina, 842 15 Bratislava, Slovak Republic
| | - Yvetta Gbelska
- Comenius University in Bratislava, Faculty of Natural Sciences, Department of Microbiology and Virology, Ilkovicova 6, Mlynska dolina, 842 15 Bratislava, Slovak Republic.,Comenius University in Bratislava, Faculty of Natural Sciences, Department of Microbiology and Virology, Ilkovicova 6, Mlynska dolina, 842 15 Bratislava, Slovak Republic
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Pais P, Costa C, Cavalheiro M, Romão D, Teixeira MC. Transcriptional Control of Drug Resistance, Virulence and Immune System Evasion in Pathogenic Fungi: A Cross-Species Comparison. Front Cell Infect Microbiol 2016; 6:131. [PMID: 27812511 PMCID: PMC5072224 DOI: 10.3389/fcimb.2016.00131] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 09/29/2016] [Indexed: 12/26/2022] Open
Abstract
Transcription factors are key players in the control of the activation or repression of gene expression programs in response to environmental stimuli. The study of regulatory networks taking place in fungal pathogens is a promising research topic that can help in the fight against these pathogens by targeting specific fungal pathways as a whole, instead of targeting more specific effectors of virulence or drug resistance. This review is focused on the analysis of regulatory networks playing a central role in the referred mechanisms in the human fungal pathogens Aspergillus fumigatus, Cryptococcus neoformans, Candida albicans, Candida glabrata, Candida parapsilosis, and Candida tropicalis. Current knowledge on the activity of the transcription factors characterized in each of these pathogenic fungal species will be addressed. Particular focus is given to their mechanisms of activation, regulatory targets and phenotypic outcome. The review further provides an evaluation on the conservation of transcriptional circuits among different fungal pathogens, highlighting the pathways that translate common or divergent traits among these species in what concerns their drug resistance, virulence and host immune evasion features. It becomes evident that the regulation of transcriptional networks is complex and presents significant variations among different fungal pathogens. Only the oxidative stress regulators Yap1 and Skn7 are conserved among all studied species; while some transcription factors, involved in nutrient homeostasis, pH adaptation, drug resistance and morphological switching are present in several, though not all species. Interestingly, in some cases not very homologous transcription factors display orthologous functions, whereas some homologous proteins have diverged in terms of their function in different species. A few cases of species specific transcription factors are also observed.
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Affiliation(s)
- Pedro Pais
- Biological Sciences Research Group, Department of Bioengineering, Instituto Superior Técnico, Universidade de LisboaLisbon, Portugal; Biological Sciences Research Group, Institute for Bioengineering and Biosciences, Instituto Superior TécnicoLisboa, Portugal
| | - Catarina Costa
- Biological Sciences Research Group, Department of Bioengineering, Instituto Superior Técnico, Universidade de LisboaLisbon, Portugal; Biological Sciences Research Group, Institute for Bioengineering and Biosciences, Instituto Superior TécnicoLisboa, Portugal
| | - Mafalda Cavalheiro
- Biological Sciences Research Group, Department of Bioengineering, Instituto Superior Técnico, Universidade de LisboaLisbon, Portugal; Biological Sciences Research Group, Institute for Bioengineering and Biosciences, Instituto Superior TécnicoLisboa, Portugal
| | - Daniela Romão
- Biological Sciences Research Group, Department of Bioengineering, Instituto Superior Técnico, Universidade de LisboaLisbon, Portugal; Biological Sciences Research Group, Institute for Bioengineering and Biosciences, Instituto Superior TécnicoLisboa, Portugal
| | - Miguel C Teixeira
- Biological Sciences Research Group, Department of Bioengineering, Instituto Superior Técnico, Universidade de LisboaLisbon, Portugal; Biological Sciences Research Group, Institute for Bioengineering and Biosciences, Instituto Superior TécnicoLisboa, Portugal
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Gohar AA, Badali H, Shokohi T, Nabili M, Amirrajab N, Moazeni M. Expression Patterns of ABC Transporter Genes in Fluconazole-Resistant Candida glabrata. Mycopathologia 2016; 182:273-284. [PMID: 27744635 DOI: 10.1007/s11046-016-0074-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 09/29/2016] [Indexed: 11/24/2022]
Abstract
Clinical management of fungal diseases is compromised by the emergence of antifungal drug resistance in fungi, which leads to elimination of available drug classes as treatment options. An understanding of antifungal resistance at molecular level is, therefore, essential for the development of strategies to combat the resistance. This study presents the assessment of molecular mechanisms associated with fluconazole resistance in clinical Candida glabrata isolates originated from Iran. Taking seven distinct fluconazole-resistant C. glabrata isolates, real-time PCRs were performed to evaluate the alternations in the regulation of the genes involved in drug efflux including CgCDR1, CgCDR2, CgSNQ2, and CgERG11. Gain-of-function (GOF) mutations in CgPDR1 alleles were determined by DNA sequencing. Cross-resistance to fluconazole, itraconazole, and voriconazole was observed in 2.5 % of the isolates. In the present study, six amino acid substitutions were identified in CgPdr1, among which W297R, T588A, and F575L were previously reported, whereas D243N, H576Y, and P915R are novel. CgCDR1 overexpression was observed in 57.1 % of resistant isolates. However, CgCDR2 was not co-expressed with CgCDR1. CgSNQ2 was upregulated in 71.4 % of the cases. CgERG11 overexpression does not seem to be associated with azole resistance, except for isolates that exhibited azole cross-resistance. The pattern of efflux pump gene upregulation was associated with GOF mutations observed in CgPDR1. These results showed that drug efflux mediated by adenosine-5-triphosphate (ATP)-binding cassette transporters, especially CgSNQ2 and CgCDR1, is the predominant mechanism of fluconazole resistance in Iranian isolates of C. glabrata. Since some novel GOF mutations were found here, this study also calls for research aimed at investigating other new GOF mutations to reveal the comprehensive understanding about efflux-mediated resistance to azole antifungal agents.
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Affiliation(s)
| | - Hamid Badali
- Invasive Fungi Research Centre, Mazandaran University of Medical Sciences, Sari, Iran.,Department of Medical Mycology and Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - Tahereh Shokohi
- Invasive Fungi Research Centre, Mazandaran University of Medical Sciences, Sari, Iran.,Department of Medical Mycology and Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - Mojtaba Nabili
- Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran.,Iranian Social Security Organization, Mazandaran, Iran
| | - Nasrin Amirrajab
- Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran.,Department of Laboratory Sciences, School of Paramedicine/Infectious and Tropical Diseases Research Centre, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Maryam Moazeni
- Invasive Fungi Research Centre, Mazandaran University of Medical Sciences, Sari, Iran. .,Department of Medical Mycology and Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.
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Kodedová M, Sychrová H. High-throughput fluorescence screening assay for the identification and comparison of antimicrobial peptides’ activity on various yeast species. J Biotechnol 2016; 233:26-33. [DOI: 10.1016/j.jbiotec.2016.06.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 06/06/2016] [Accepted: 06/28/2016] [Indexed: 11/29/2022]
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Heteroresistance to Fluconazole Is a Continuously Distributed Phenotype among Candida glabrata Clinical Strains Associated with In Vivo Persistence. mBio 2016; 7:mBio.00655-16. [PMID: 27486188 PMCID: PMC4981708 DOI: 10.1128/mbio.00655-16] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Candida glabrata causes persistent infections in patients treated with fluconazole and often acquires resistance following exposure to the drug. Here we found that clinical strains of C. glabrata exhibit cell-to-cell variation in drug response (heteroresistance). We used population analysis profiling (PAP) to assess fluconazole heteroresistance (FLCHR) and to ask if it is a binary trait or a continuous phenotype. Thirty (57.6%) of 52 fluconazole-sensitive clinical C. glabrata isolates met accepted dichotomous criteria for FLCHR. However, quantitative grading of FLCHR by using the area under the PAP curve (AUC) revealed a continuous distribution across a wide range of values, suggesting that all isolates exhibit some degree of heteroresistance. The AUC correlated with rhodamine 6G efflux and was associated with upregulation of the CDR1 and PDH1 genes, encoding ATP-binding cassette (ABC) transmembrane transporters, implying that HetR populations exhibit higher levels of drug efflux. Highly FLCHRC. glabrata was recovered more frequently than nonheteroresistant C. glabrata from hematogenously infected immunocompetent mice following treatment with high-dose fluconazole (45.8% versus 15%, P = 0.029). Phylogenetic analysis revealed some phenotypic clustering but also variations in FLCHR within clonal groups, suggesting both genetic and epigenetic determinants of heteroresistance. Collectively, these results establish heteroresistance to fluconazole as a graded phenotype associated with ABC transporter upregulation and fluconazole efflux. Heteroresistance may explain the propensity of C. glabrata for persistent infection and the emergence of breakthrough resistance to fluconazole. Heteroresistance refers to variability in the response to a drug within a clonal cell population. This phenomenon may have crucial importance for the way we look at antimicrobial resistance, as heteroresistant strains are not detected by standard laboratory susceptibility testing and may be associated with failure of antimicrobial therapy. We describe for the first time heteroresistance to fluconazole in C. glabrata, a finding that may explain the propensity of this pathogen to acquire resistance following exposure to fluconazole and to persist despite treatment. We found that, rather than being a binary all-or-none trait, heteroresistance was a continuously distributed phenotype associated with increased expression of genes that encode energy-dependent drug efflux transporters. Moreover, we show that heteroresistance is associated with failure of fluconazole to clear infection with C. glabrata. Together, these findings provide an empirical framework for determining and quantifying heteroresistance in C. glabrata.
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Vitali A, Vavala E, Marzano V, Leone C, Castagnola M, Iavarone F, Angiolella L. Cell wall composition and biofilm formation of azoles-susceptible and -resistant Candida glabrata strains. J Chemother 2016; 29:164-172. [PMID: 27439026 DOI: 10.1080/1120009x.2016.1199507] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
In the present study, three strains of Candida glabrata have been investigated to shed light on the mechanisms involved in azole resistance during adherence and biofilm formation. In particular, a clinical isolate, susceptible to azole-based drugs, DSY562 and two different resistant mutagenic strains deriving from DSY562, SFY114 and SFY115, have been analysed with different approaches for their cell wall composition and properties. A proteomic analysis revealed that the expression of six cell wall-related proteins and biofilm formation varied between the strains. The SFY114 and SFY115 strains resulted to be less hydrophobic than the susceptible parental counterpart DSY562, on the other hand they showed a higher amount in total cell wall polysaccharides fraction in the total cell wall. Accordingly to the results obtained from the hydrophobicity and adherence assays, in the resistant strain SFY115 the biofilm formation decreased compared to the parental strain DSY562. Finally, the total glucose amount in resistant SFY115 was about halved in comparison to other strains. Taken together all these data suggest that azole drugs may affect the cell wall composition of C. glabrata, in relation to the different pathogenic behaviours.
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Affiliation(s)
- Alberto Vitali
- a CNR-ICRM, c/o Institute of Biochemistry and Clinical Biochemistry , Catholic University , Largo F. Vito 1, Rome 00168 , Italy
| | - Elisabetta Vavala
- b Department of Public Health and Infectious Diseases , "Sapienza" University of Rome , P.le Aldo Moro 5, Rome 00161 , Italy
| | - Valeria Marzano
- c Institute of Biochemistry and Clinical Biochemistry , Catholic University , Largo F. Vito 1, Rome 00168 , Italy
| | - Claudia Leone
- b Department of Public Health and Infectious Diseases , "Sapienza" University of Rome , P.le Aldo Moro 5, Rome 00161 , Italy
| | - Massimo Castagnola
- c Institute of Biochemistry and Clinical Biochemistry , Catholic University , Largo F. Vito 1, Rome 00168 , Italy
| | - Federica Iavarone
- c Institute of Biochemistry and Clinical Biochemistry , Catholic University , Largo F. Vito 1, Rome 00168 , Italy
| | - Letizia Angiolella
- b Department of Public Health and Infectious Diseases , "Sapienza" University of Rome , P.le Aldo Moro 5, Rome 00161 , Italy
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Hernando-Amado S, Blanco P, Alcalde-Rico M, Corona F, Reales-Calderón JA, Sánchez MB, Martínez JL. Multidrug efflux pumps as main players in intrinsic and acquired resistance to antimicrobials. Drug Resist Updat 2016; 28:13-27. [PMID: 27620952 DOI: 10.1016/j.drup.2016.06.007] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 05/31/2016] [Accepted: 06/23/2016] [Indexed: 12/31/2022]
Abstract
Multidrug efflux pumps constitute a group of transporters that are ubiquitously found in any organism. In addition to other functions with relevance for the cell physiology, efflux pumps contribute to the resistance to compounds used for treating different diseases, including resistance to anticancer drugs, antibiotics or antifungal compounds. In the case of antimicrobials, efflux pumps are major players in both intrinsic and acquired resistance to drugs currently in use for the treatment of infectious diseases. One important aspect not fully explored of efflux pumps consists on the identification of effectors able to induce their expression. Indeed, whereas the analysis of clinical isolates have shown that mutants overexpressing these resistance elements are frequently found, less is known on the conditions that may trigger expression of efflux pumps, hence leading to transient induction of resistance in vivo, a situation that is barely detectable using classical susceptibility tests. In the current article we review the structure and mechanisms of regulation of the expression of bacterial and fungal efflux pumps, with a particular focus in those for which a role in clinically relevant resistance has been reported.
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Affiliation(s)
- Sara Hernando-Amado
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain
| | - Paula Blanco
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain
| | - Manuel Alcalde-Rico
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain
| | - Fernando Corona
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain
| | - Jose A Reales-Calderón
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain
| | - María B Sánchez
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain
| | - José L Martínez
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco, 28049 Madrid, Spain.
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132
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Katiyar S, Shiffrin E, Shelton C, Healey K, Vermitsky JP, Edlind T. Evaluation of Polymorphic Locus Sequence Typing for Candida glabrata Epidemiology. J Clin Microbiol 2016; 54:1042-50. [PMID: 26842706 PMCID: PMC4809956 DOI: 10.1128/jcm.03106-15] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 01/29/2016] [Indexed: 11/20/2022] Open
Abstract
The opportunistic yeast Candida glabratais increasingly refractory to antifungal treatment or prophylaxis and relatedly is increasingly implicated in health care-associated infections. To elucidate the epidemiology of these infections, strain typing is required. Sequence-based typing provides multiple advantages over length-based methods, such as pulsed-field gel electrophoresis (PFGE); however, conventional multilocus sequence typing (targeting 6 conserved loci) and whole-genome sequencing are impractical for routine use. A commercial sequence-based typing service for C. glabratathat targets polymorphic tandem repeat-containing loci has recently been developed. These CgMT-J and CgMT-M services were evaluated with 56 epidemiologically unrelated isolates, 4 to 7 fluconazole-susceptible or fluconazole-resistant isolates from each of 5 center A patients, 5 matched pairs of fluconazole-susceptible/resistant isolates from center B patients, and 7 isolates from a center C patient who responded to then failed caspofungin therapy. CgMT-J and CgMT-M generated congruent results, resolving isolates into 24 and 20 alleles, respectively. Isolates from all but one of the center A patients shared the same otherwise rare alleles, suggesting nosocomial transmission. Unexpectedly, Pdr1 sequencing showed that resistance arose independently in each patient. Similarly, most isolates from center B also clustered together; however, this may reflect a dominant clone since their alleles were shared by multiple unrelated isolates. Although distinguishable by their echinocandin susceptibilities, all isolates from the center C patient shared alleles, in agreement with the previously reported relatedness of these isolates based on PFGE. Finally, we show how phylogenetic clusters can be used to provide surrogate parents to analyze the mutational basis for antifungal resistance.
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Affiliation(s)
- Santosh Katiyar
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Eric Shiffrin
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Celeste Shelton
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Kelley Healey
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - John-Paul Vermitsky
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Tom Edlind
- MicrobiType LLC, Plymouth Meeting, Pennsylvania, USA
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Sanglard D. Emerging Threats in Antifungal-Resistant Fungal Pathogens. Front Med (Lausanne) 2016; 3:11. [PMID: 27014694 PMCID: PMC4791369 DOI: 10.3389/fmed.2016.00011] [Citation(s) in RCA: 233] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 03/03/2016] [Indexed: 12/15/2022] Open
Abstract
The use of antifungal drugs in the therapy of fungal diseases can lead to the development of antifungal resistance. Resistance has been described for virtually all antifungal agents in diverse pathogens, including Candida and Aspergillus species. The majority of resistance mechanisms have also been elucidated at the molecular level in these pathogens. Drug resistance genes and genome mutations have been identified. Therapeutic choices are limited for the control of fungal diseases, and it is tempting to combine several drugs to achieve better therapeutic efficacy. In the recent years, several novel resistance patterns have been observed, including antifungal resistance originating from environmental sources in Aspergillus fumigatus and the emergence of simultaneous resistance to different antifungal classes (multidrug resistance) in different Candida species. This review will summarize these current trends.
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Affiliation(s)
- Dominique Sanglard
- Institute of Microbiology, University Hospital Center, University of Lausanne , Lausanne , Switzerland
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Upregulation of the Adhesin Gene EPA1 Mediated by PDR1 in Candida glabrata Leads to Enhanced Host Colonization. mSphere 2016; 1:mSphere00065-15. [PMID: 27303714 PMCID: PMC4863579 DOI: 10.1128/msphere.00065-15] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 01/27/2016] [Indexed: 11/20/2022] Open
Abstract
Candida glabrata is an important fungal pathogen in human diseases and is also rapidly acquiring drug resistance. Drug resistance can be mediated by the transcriptional activator PDR1, and this results in the upregulation of multidrug transporters. Intriguingly, this resistance mechanism is associated in C. glabrata with increased virulence in animal models and also with increased adherence to specific host cell types. The C. glabrata adhesin gene EPA1 is a major contributor of virulence and adherence to host cells. Here, we show that EPA1 expression is controlled by PDR1 independently of subtelomeric silencing, a known EPA1 regulation mechanism. Thus, a relationship exists between PDR1, EPA1 expression, and adherence to host cells, which is critical for efficient virulence. Our results demonstrate that acquisition of drug resistance is beneficial for C. glabrata in fungus-host relationships. These findings further highlight the challenges of the therapeutic management of C. glabrata infections in human patients. Candida glabrata is the second most common Candida species causing disseminated infection, after C. albicans. C. glabrata is intrinsically less susceptible to the widely used azole antifungal drugs and quickly develops secondary resistance. Resistance typically relies on drug efflux with transporters regulated by the transcription factor Pdr1. Gain-of-function (GOF) mutations in PDR1 lead to a hyperactive state and thus efflux transporter upregulation. Our laboratory has characterized a collection of C. glabrata clinical isolates in which azole resistance was found to correlate with increased virulence in vivo. Contributing phenotypes were the evasion of adhesion and phagocytosis by macrophages and an increased adhesion to epithelial cells. These phenotypes were found to be dependent on PDR1 GOF mutation and/or C. glabrata strain background. In the search for the molecular effectors, we found that PDR1 hyperactivity leads to overexpression of specific cell wall adhesins of C. glabrata. Further study revealed that EPA1 regulation, in particular, explained the increase in adherence to epithelial cells. Deleting EPA1 eliminates the increase in adherence in an in vitro model of interaction with epithelial cells. In a murine model of urinary tract infection, PDR1 hyperactivity conferred increased ability to colonize the bladder and kidneys in an EPA1-dependent way. In conclusion, this study establishes a relationship between PDR1 and the regulation of cell wall adhesins, an important virulence attribute of C. glabrata. Furthermore, our data show that PDR1 hyperactivity mediates increased adherence to host epithelial tissues both in vitro and in vivo through upregulation of the adhesin gene EPA1. IMPORTANCECandida glabrata is an important fungal pathogen in human diseases and is also rapidly acquiring drug resistance. Drug resistance can be mediated by the transcriptional activator PDR1, and this results in the upregulation of multidrug transporters. Intriguingly, this resistance mechanism is associated in C. glabrata with increased virulence in animal models and also with increased adherence to specific host cell types. The C. glabrata adhesin gene EPA1 is a major contributor of virulence and adherence to host cells. Here, we show that EPA1 expression is controlled by PDR1 independently of subtelomeric silencing, a known EPA1 regulation mechanism. Thus, a relationship exists between PDR1, EPA1 expression, and adherence to host cells, which is critical for efficient virulence. Our results demonstrate that acquisition of drug resistance is beneficial for C. glabrata in fungus-host relationships. These findings further highlight the challenges of the therapeutic management of C. glabrata infections in human patients.
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Inhibiting fungal multidrug resistance by disrupting an activator-Mediator interaction. Nature 2016; 530:485-9. [PMID: 26886795 PMCID: PMC4860947 DOI: 10.1038/nature16963] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 12/29/2015] [Indexed: 02/06/2023]
Abstract
Eukaryotic transcription activators stimulate the expression of specific sets of target genes through recruitment of co-activators such as the RNA polymerase II-interacting Mediator complex. Aberrant function of transcription activators has been implicated in several diseases. However, therapeutic targeting efforts have been hampered by a lack of detailed molecular knowledge of the mechanisms of gene activation by disease-associated transcription activators. We previously identified an activator-targeted three-helix bundle KIX domain in the human MED15 Mediator subunit that is structurally conserved in Gal11/Med15 Mediator subunits in fungi. The Gal11/Med15 KIX domain engages pleiotropic drug resistance transcription factor (Pdr1) orthologues, which are key regulators of the multidrug resistance pathway in Saccharomyces cerevisiae and in the clinically important human pathogen Candida glabrata. The prevalence of C. glabrata is rising, partly owing to its low intrinsic susceptibility to azoles, the most widely used antifungal agent. Drug-resistant clinical isolates of C. glabrata most commonly contain point mutations in Pdr1 that render it constitutively active, suggesting that this transcriptional activation pathway represents a linchpin in C. glabrata multidrug resistance. Here we perform sequential biochemical and in vivo high-throughput screens to identify small-molecule inhibitors of the interaction of the C. glabrata Pdr1 activation domain with the C. glabrata Gal11A KIX domain. The lead compound (iKIX1) inhibits Pdr1-dependent gene activation and re-sensitizes drug-resistant C. glabrata to azole antifungals in vitro and in animal models for disseminated and urinary tract C. glabrata infection. Determining the NMR structure of the C. glabrata Gal11A KIX domain provides a detailed understanding of the molecular mechanism of Pdr1 gene activation and multidrug resistance inhibition by iKIX1. We have demonstrated the feasibility of small-molecule targeting of a transcription factor-binding site in Mediator as a novel therapeutic strategy in fungal infectious disease.
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Kołaczkowska A, Kołaczkowski M. Drug resistance mechanisms and their regulation in non-albicans Candida species. J Antimicrob Chemother 2016; 71:1438-50. [PMID: 26801081 DOI: 10.1093/jac/dkv445] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Fungal pathogens use various mechanisms to survive exposure to drugs. Prolonged treatment very often leads to the stepwise acquisition of resistance. The limited number of antifungal therapeutics and their mostly fungistatic rather than fungicidal character facilitates selection of resistant strains. These are able to cope with cytotoxic molecules by acquisition of appropriate mutations, re-wiring gene expression and metabolic adjustments. Recent evidence points to the paramount importance of the permeability barrier and cell wall integrity in the process of adaptation to high drug concentrations. Molecular details of basal and acquired drug resistance are best characterized in the most frequent human fungal pathogen, Candida albicans Effector genes directly related to the acquisition of elevated tolerance of this species to azole and echinocandin drugs are well described. The emergence of high-level drug resistance against intrinsically lower susceptibility to azoles in yeast species other than C. albicans is, however, of particular concern. This is due to their steadily increasing contribution to high mortality rates associated with disseminated infections. Recent findings concerning underlying mechanisms associated with elevated drug resistance suggest a link to cell wall and plasma membrane metabolism in non-albicans Candida species.
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Affiliation(s)
- Anna Kołaczkowska
- Department of Biochemistry, Pharmacology and Toxicology, Wroclaw University of Environmental and Life Sciences, Norwida 31, PL 50-375, Wroclaw, Poland
| | - Marcin Kołaczkowski
- Department of Biophysics, Wroclaw Medical University, Chalubinskiego 10, PL50-368, Wroclaw, Poland
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Activity of Isavuconazole and Other Azoles against Candida Clinical Isolates and Yeast Model Systems with Known Azole Resistance Mechanisms. Antimicrob Agents Chemother 2015; 60:229-38. [PMID: 26482310 DOI: 10.1128/aac.02157-15] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 10/13/2015] [Indexed: 11/20/2022] Open
Abstract
Isavuconazole is a novel, broad-spectrum, antifungal azole. In order to evaluate its interactions with known azole resistance mechanisms, isavuconazole susceptibility among different yeast models and clinical isolates expressing characterized azole resistance mechanisms was tested and compared to those of fluconazole, itraconazole, posaconazole, and voriconazole. Saccharomyces cerevisiae expressing the Candida albicans and C. glabrata ATP binding cassette (ABC) transporters (CDR1, CDR2, and CgCDR1), major facilitator (MDR1), and lanosterol 14-α-sterol-demethylase (ERG11) alleles with mutations were used. In addition, pairs of C. albicans and C. glabrata strains from matched clinical isolates with known azole resistance mechanisms were investigated. The expression of ABC transporters increased all azole MICs, suggesting that all azoles tested were substrates of ABC transporters. The expression of MDR1 did not increase posaconazole, itraconazole, and isavuconazole MICs. Relative increases of azole MICs (from 4- to 32-fold) were observed for fluconazole, voriconazole, and isavuconazole when at least two mutations were present in the same ERG11 allele. Upon MIC testing of azoles with clinical C. albicans and C. glabrata isolates with known resistance mechanisms, the MIC90s of C. albicans for fluconazole, voriconazole, itraconazole, posaconazole, and isavuconazole were 128, 2, 1, 0.5, and 2 μg/ml, respectively, while in C. glabrata they were 128, 2, 4, 4, and 16 μg/ml, respectively. In conclusion, the effects of azole resistance mechanisms on isavuconazole did not differ significantly from those of other azoles. Resistance mechanisms in yeasts involving ABC transporters and ERG11 decreased the activity of isavuconazole, while MDR1 had limited effect.
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138
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Usher J, Thomas G, Haynes K. Utilising established SDL-screening methods as a tool for the functional genomic characterisation of model and non-model organisms. FEMS Yeast Res 2015; 15:fov091. [PMID: 26472754 DOI: 10.1093/femsyr/fov091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2015] [Indexed: 12/21/2022] Open
Abstract
The trend for large-scale genetic and phenotypic screens has revealed a wealth of information on biological systems. A major challenge is understanding how genes function and putative roles in networks. The majority of current gene knowledge is garnered from studies utilising the model yeast Saccharomyces cerevisiae. We demonstrate that synthetic dosage lethal genetic array methodologies can be used to study genetic networks in other yeasts, namely the fungal pathogen Candida glabrata, which has limited forward genetic tools, due to the lack of 'natural' mating. We performed two SDL screens in S. cerevisiae, overexpressing the transcriptional regulator UME6 as bait in the first screen and its C. glabrata ortholog CAGL0F05357g in the second. Analysis revealed that SDL maps share 204 common interactors, with 10 genetic interactions unique to C. glabrata indicating a level of genetic rewiring, indicative of linking genotype to phenotype in fungal pathogens. This was further validated by incorporating our results into the global genetic landscape map of the cell from Costanzo et al. to identify common and novel gene attributes. This data demonstrated the utility large data sets and more robust analysis made possible by interrogating exogenous genes in the context of the eukaryotic global genetic landscape.
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Affiliation(s)
- Jane Usher
- Department of Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Graham Thomas
- Department of Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Ken Haynes
- Department of Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
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139
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Roy S, Thompson D. Evolution of regulatory networks in Candida glabrata: learning to live with the human host. FEMS Yeast Res 2015; 15:fov087. [PMID: 26449820 DOI: 10.1093/femsyr/fov087] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/17/2015] [Indexed: 12/12/2022] Open
Abstract
The opportunistic human fungal pathogen Candida glabrata is second only to C. albicans as the cause of Candida infections and yet is more closely related to Saccharomyces cerevisiae. Recent advances in functional genomics technologies and computational approaches to decipher regulatory networks, and the comparison of these networks among these and other Ascomycete species, have revealed both unique and shared strategies in adaptation to a human commensal/opportunistic pathogen lifestyle and antifungal drug resistance in C. glabrata. Recently, several C. glabrata sister species in the Nakeseomyces clade representing both human associated (commensal) and environmental isolates have had their genomes sequenced and analyzed. This has paved the way for comparative functional genomics studies to characterize the regulatory networks in these species to identify informative patterns of conservation and divergence linked to phenotypic evolution in the Nakaseomyces lineage.
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Affiliation(s)
- Sushmita Roy
- Department of Biostatistics and Medical Informatics, University of Wisconsin Madison, Madison, WI 53715, USA Wisconsin Institute for Discovery, University of Wisconsin, Madison, WI 53715, USA
| | - Dawn Thompson
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
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140
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Fitness Studies of Azole-Resistant Strains of Aspergillus fumigatus. Antimicrob Agents Chemother 2015; 59:7866-9. [PMID: 26416854 DOI: 10.1128/aac.01594-15] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 09/21/2015] [Indexed: 11/20/2022] Open
Abstract
Isogenic bar-coded strains of Aspergillus fumigatus carrying the G54W or M220K mutation in Cyp51A were constructed. In vitro, the growth and conidiation capacities of the mutants were similar to those of the parental strain. Competition studies in the absence of azoles showed that there was no adverse fitness cost for the azole-resistant A. fumigatus strains in vitro or in vivo compared to the parental strain.
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141
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Tam P, Gee K, Piechocinski M, Macreadie I. Candida glabrata, Friend and Foe. J Fungi (Basel) 2015; 1:277-292. [PMID: 29376912 PMCID: PMC5753114 DOI: 10.3390/jof1020277] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 09/07/2015] [Accepted: 09/09/2015] [Indexed: 11/16/2022] Open
Abstract
Candida glabrata is mostly good, but, at times, it is an opportunistic pathogen. Previously known as Torulopsis glabrata, it enjoyed a good reputation and was even present in starter cultures. Its haploid genome and lack of mating made it an attractive challenge for yeast genetics studies. However, more recently it has become better known due to its character as an emerging cause of candidiasis, and for its resistance to multidrugs that are employed for candidiasis treatment. While now classified as Candida glabrata, it is still not a good fit and tends to stand alone as a very unique yeast. In terms of sequence, it is dissimilar to other Candida yeast and most similar to Saccharomyces cerevisiae.
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Affiliation(s)
- Phyllix Tam
- School of Applied Sciences, RMIT University, Bundoora, Victoria 3083, Australia.
| | - Kirsten Gee
- School of Applied Sciences, RMIT University, Bundoora, Victoria 3083, Australia.
| | - Miryam Piechocinski
- School of Applied Sciences, RMIT University, Bundoora, Victoria 3083, Australia.
| | - Ian Macreadie
- School of Applied Sciences, RMIT University, Bundoora, Victoria 3083, Australia.
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142
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Zavrel M, White TC. Medically important fungi respond to azole drugs: an update. Future Microbiol 2015; 10:1355-73. [DOI: 10.2217/fmb.15.47] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The increased numbers of patients with compromised immune systems in the last three decades have increased the chances of life-threatening fungal infections. Numerous antifungal drugs have been developed in the last 20 years to treat these infections. The largest group, the azoles, inhibits the synthesis of fungal sterols. The use of these fungistatic azoles has subsequently led to the emergence of acquired azole resistance. The most common mechanisms that result in azole resistance include the overexpression or mutation of the azole target enzyme, and overexpression of drug transporters that are responsible for azole efflux from cells. Additional, less-frequent mechanisms have also been identified. Understanding azole resistance mechanisms is crucial for current antifungal treatment and for the future development of new treatment strategies.
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Affiliation(s)
- Martin Zavrel
- University of Missouri-Kansas City, School of Biological Sciences, Division of Cell Biology & Biophysics, 5007 Rockhill Road, BSB 404, Kansas City, MO 64110, USA
| | - Theodore C White
- University of Missouri-Kansas City, School of Biological Sciences, Division of Cell Biology & Biophysics, 5007 Rockhill Road, BSB 404, Kansas City, MO 64110, USA
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143
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Kasper L, Seider K, Hube B. Intracellular survival of Candida glabrata in macrophages: immune evasion and persistence. FEMS Yeast Res 2015; 15:fov042. [PMID: 26066553 DOI: 10.1093/femsyr/fov042] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/05/2015] [Indexed: 12/11/2022] Open
Abstract
Candida glabrata is a successful human opportunistic pathogen which causes superficial but also life-threatening systemic infections. During infection, C. glabrata has to cope with cells of the innate immune system such as macrophages, which belong to the first line of defense against invading pathogens. Candida glabrata is able to survive and even replicate inside macrophages while causing surprisingly low damage and cytokine release. Here, we present an overview of recent studies dealing with the interaction of C. glabrata with macrophages, from phagocytosis to intracellular growth and escape. We review the strategies of C. glabrata that permit intracellular survival and replication, including poor host cell activation, modification of phagosome maturation and phagosome pH, adaptation to antimicrobial activities, and mechanisms to overcome the nutrient limitations within the phagosome. In summary, these studies suggest that survival within macrophages may be an immune evasion and persistence strategy of C. glabrata during infection.
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Affiliation(s)
- Lydia Kasper
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knoell Institute, 07745 Jena, Germany
| | - Katja Seider
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knoell Institute, 07745 Jena, Germany
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knoell Institute, 07745 Jena, Germany Integrated Research and Treatment Center, Sepsis und Sepsisfolgen, Center for Sepsis Control and Care (CSCC), University Hospital, 07747 Jena, Germany Friedrich Schiller University, 07743 Jena, Germany
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144
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Garnaud C, Botterel F, Sertour N, Bougnoux ME, Dannaoui E, Larrat S, Hennequin C, Guinea J, Cornet M, Maubon D. Next-generation sequencing offers new insights into the resistance of Candida spp. to echinocandins and azoles. J Antimicrob Chemother 2015; 70:2556-65. [PMID: 26017039 DOI: 10.1093/jac/dkv139] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 04/24/2015] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES MDR Candida strains are emerging. Next-generation sequencing (NGS), which enables extensive and deep genome analysis, was used to investigate echinocandin and azole resistance in clinical Candida isolates. METHODS Six genes commonly involved in antifungal resistance (ERG11, ERG3, TAC1, CgPDR1, FKS1 and FKS2) were analysed using NGS in 40 Candida isolates (18 Candida albicans, 15 Candida glabrata and 7 Candida parapsilosis). The strategy was validated using strains with known sequences. Then, 8 clinical strains displaying antifungal resistance and 23 sequential isolates collected from 10 patients receiving antifungal therapy were analysed. RESULTS A total of 391 SNPs were detected, among which 6 coding SNPs were reported for the first time. Novel genetic alterations were detected in both azole and echinocandin resistance genes. A C. glabrata strain, which was resistant to echinocandins but highly susceptible to azoles, harboured an FKS2 S663P mutation plus a novel presumed loss-of-function CgPDR1 mutation. This isolate was from a patient with deep-seated and urinary candidiasis. Another C. glabrata isolate, with an MDR phenotype, carried a new FKS2 S663A mutation and a new putative gain-of-function CgPDR1 mutation (T370I); this isolate showed mutated (80%) and WT (20%) populations and was collected after 75 days of exposure to caspofungin from a patient who underwent complicated abdominal surgery. CONCLUSIONS This study shows that NGS can be used for extensive assessment of genetic mutations involved in antifungal resistance. This type of wide genome approach will become very valuable for detecting mechanisms of resistance in clinical strains subjected to multidrug pressure.
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Affiliation(s)
- Cécile Garnaud
- Laboratoire de Parasitologie-Mycologie, Institut de Biologie et de Pathologie, CHU de Grenoble, Grenoble, France Laboratoire TIMC-TheREx, UMR 5525 CNRS-UJF, Université Grenoble Alpes, Grenoble, France
| | - Françoise Botterel
- Unité de Parasitologie-Mycologie, Département de Virologie, Bactériologie-Hygiène, Mycologie-Parasitologie, CHU Henri Mondor, APHP, DHU VIC, Créteil, France EA Dynamyc UPEC-ENVA, Créteil, France
| | - Natacha Sertour
- Unité Biologie et Pathogénicité Fongiques-INRA USC2019, Institut Pasteur, Paris, France
| | - Marie-Elisabeth Bougnoux
- Unité Biologie et Pathogénicité Fongiques-INRA USC2019, Institut Pasteur, Paris, France Assistance Publique-Hôpitaux de Paris, Hôpital Necker Enfants Malades, Service de Microbiologie, Unité de Parasitologie-Mycologie, F-75015 Paris, France
| | - Eric Dannaoui
- EA Dynamyc UPEC-ENVA, Créteil, France Université Paris-Descartes, Faculté de Médecine, Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Unité de Parasitologie-Mycologie, Service de Microbiologie, Paris, France
| | - Sylvie Larrat
- Laboratoire de Virologie, Institut de Biologie et de Pathologie, CHU de Grenoble, Grenoble, France UVHCI UMI 3265 CNRS-UJF-EMBL, Université Grenoble Alpes, Grenoble, France
| | - Christophe Hennequin
- Assistance Publique-Hôpitaux de Paris, Hôpital St Antoine, Service de Parasitologie-Mycologie, F-75012 Paris, France Centre d'Immunologie et de Maladies Infectieuses (CIMI-Paris), Inserm U1135, CNRS ERL 8255, Sorbonne Universités, UPMC Univ Paris 06 CR7, Paris, France
| | - Jesus Guinea
- Clinical Microbiology and Infectious Diseases Department, Hospital General Universitario Gregorio Marañon, Madrid, Spain
| | - Muriel Cornet
- Laboratoire de Parasitologie-Mycologie, Institut de Biologie et de Pathologie, CHU de Grenoble, Grenoble, France Laboratoire TIMC-TheREx, UMR 5525 CNRS-UJF, Université Grenoble Alpes, Grenoble, France
| | - Danièle Maubon
- Laboratoire de Parasitologie-Mycologie, Institut de Biologie et de Pathologie, CHU de Grenoble, Grenoble, France Laboratoire TIMC-TheREx, UMR 5525 CNRS-UJF, Université Grenoble Alpes, Grenoble, France
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145
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Vale-Silva LA, Sanglard D. Tipping the balance both ways: drug resistance and virulence in Candida glabrata. FEMS Yeast Res 2015; 15:fov025. [PMID: 25979690 DOI: 10.1093/femsyr/fov025] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/11/2015] [Indexed: 01/20/2023] Open
Abstract
Among existing fungal pathogens, Candida glabrata is outstanding in its capacity to rapidly develop resistance to currently used antifungal agents. Resistance to the class of azoles, which are still widely used agents, varies in proportion (from 5 to 20%) depending on geographical area. Moreover, resistance to the class of echinocandins, which was introduced in the late 1990s, is rising in several institutions. The recent emergence of isolates with acquired resistance to both classes of agents is a major concern since alternative therapeutic options are scarce. Although considered less pathogenic than C. albicans, C. glabrata has still evolved specific virulence traits enabling its survival and propagation in colonized and infected hosts. Development of drug resistance is usually associated with fitness costs, and this notion is documented across several microbial species. Interestingly, azole resistance in C. glabrata has revealed the opposite. Experimental models of infection showed enhanced virulence of azole-resistant isolates. Moreover, azole resistance could be associated with specific changes in adherence properties to epithelial cells or innate immunity cells (macrophages), both of which contribute to virulence changes. Here we will summarize the current knowledge on C. glabrata drug resistance and also discuss the consequences of drug resistance acquisition on the balance between C. glabrata and its hosts.
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Affiliation(s)
- Luis A Vale-Silva
- Institute of Microbiology, University of Lausanne and University Hospital Center, CH-1011 Lausanne, Switzerland
| | - Dominique Sanglard
- Institute of Microbiology, University of Lausanne and University Hospital Center, CH-1011 Lausanne, Switzerland
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146
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Abstract
Invasive fungal infections remain a major source of global morbidity and mortality, especially among patients with underlying immune suppression. Successful patient management requires antifungal therapy. Yet, treatment choices are restricted due to limited classes of antifungal agents and the emergence of antifungal drug resistance. In some settings, the evolution of multidrug-resistant strains insensitive to several classes of antifungal agents is a major concern. The resistance mechanisms responsible for acquired resistance are well characterized and include changes in drug target affinity and abundance, and reduction in the intracellular level of drug by biofilms and efflux pumps. The development of high-level and multidrug resistance occurs through a stepwise evolution of diverse mechanisms. The genetic factors that influence these mechanisms are emerging and they form a complex symphony of cellular interactions that enable the cell to adapt and/or overcome drug-induced stress. Drivers of resistance involve a complex blend of host and microbial factors. Understanding these mechanisms will facilitate development of better diagnostics and therapeutic strategies to overcome and prevent antifungal resistance.
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Affiliation(s)
- David S Perlin
- Public Health Research Institute, Rutgers Biomedical and Health Sciences, New Jersey Medical School, 185 S Orange Ave, Newark, NJ 07103, USA
| | - Erika Shor
- Public Health Research Institute, Rutgers Biomedical and Health Sciences, New Jersey Medical School, 185 S Orange Ave, Newark, NJ 07103, USA
| | - Yanan Zhao
- Public Health Research Institute, Rutgers Biomedical and Health Sciences, New Jersey Medical School, 185 S Orange Ave, Newark, NJ 07103, USA
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147
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Culakova H, Dzugasova V, Valencikova R, Gbelska Y, Subik J. Stress response and expression of fluconazole resistance associated genes in the pathogenic yeast Candida glabrata deleted in the CgPDR16 gene. Microbiol Res 2015; 174:17-23. [PMID: 25946325 DOI: 10.1016/j.micres.2015.03.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 02/26/2015] [Accepted: 03/03/2015] [Indexed: 12/27/2022]
Abstract
In yeasts, the PDR16 gene encodes a phosphatidylinositol transfer protein which belongs to the Sec14 homologue (SFH) family and localizes to lipid droplets, microsomes and at the cell periphery. The loss of its function alters the lipid droplet metabolism and plasma membrane properties, and renders yeast cells more sensitive to azole antimycotics. In this study, the entire chromosomal CgPDR16 ORF was replaced by the ScURA3 gene both in azole sensitive and azole resistant strains of Candida glabrata bearing a gain-of-function mutation in the CgPDR1 gene, and their responses to different stresses were assessed. The CgPDR16 deletion was found to sensitize the mutant strains to azole antifungals without changes in their osmo- and halotolerance. Fluconazole treated pdr16Δ mutant strains displayed a reduced expression of several genes involved in azole tolerance. The gain-of-function CgPDR1 allele as well as the cycloheximide and hydrogen peroxide treatments of cells enhanced the expression of the CgPDR16 gene. The results indicate that CgPDR16 belongs to genes whose expression is induced by chemical and oxidative stresses. The loss of its function can attenuate the expression of drug efflux pump encoding genes that might also contribute to the decreased azole tolerance in pdr16Δ mutant cells.
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Affiliation(s)
- Hana Culakova
- Department of Microbiology and Virology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15 Bratislava, Slovak Republic
| | - Vladimira Dzugasova
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15 Bratislava, Slovak Republic
| | - Romana Valencikova
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15 Bratislava, Slovak Republic
| | - Yvetta Gbelska
- Department of Microbiology and Virology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15 Bratislava, Slovak Republic
| | - Julius Subik
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15 Bratislava, Slovak Republic.
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148
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Hull CM, Purdy NJ, Moody SC. Mitigation of human-pathogenic fungi that exhibit resistance to medical agents: can clinical antifungal stewardship help? Future Microbiol 2015; 9:307-25. [PMID: 24762306 DOI: 10.2217/fmb.13.160] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Reducing indiscriminate antimicrobial usage to combat the expansion of multidrug-resistant human-pathogenic bacteria is fundamental to clinical antibiotic stewardship. In contrast to bacteria, fungal resistance traits are not understood to be propagated via mobile genetic elements, and it has been proposed that a global explosion of resistance to medical antifungals is therefore unlikely. Clinical antifungal stewardship has focused instead on reducing the drug toxicity and high costs associated with medical agents. Mitigating the problem of human-pathogenic fungi that exhibit resistance to antimicrobials is an emergent issue. This article addresses the extent to which clinical antifungal stewardship could influence the scale and epidemiology of resistance to medical antifungals both now and in the future. The importance of uncharted selection pressure exerted by agents outside the clinical setting (agricultural pesticides, industrial xenobiotics, biocides, pharmaceutical waste and others) on environmentally ubiquitous spore-forming molds that are lesserstudied but increasingly responsible for drug-refractory infections is considered.
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Affiliation(s)
- Claire M Hull
- Swansea University, College of Medicine, Institute of Life Science: Microbes & Immunity, SA2 8PP, Wales, UK
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149
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Cowen LE, Sanglard D, Howard SJ, Rogers PD, Perlin DS. Mechanisms of Antifungal Drug Resistance. Cold Spring Harb Perspect Med 2014; 5:a019752. [PMID: 25384768 DOI: 10.1101/cshperspect.a019752] [Citation(s) in RCA: 354] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Antifungal therapy is a central component of patient management for acute and chronic mycoses. Yet, treatment choices are restricted because of the sparse number of antifungal drug classes. Clinical management of fungal diseases is further compromised by the emergence of antifungal drug resistance, which eliminates available drug classes as treatment options. Once considered a rare occurrence, antifungal drug resistance is on the rise in many high-risk medical centers. Most concerning is the evolution of multidrug- resistant organisms refractory to several different classes of antifungal agents, especially among common Candida species. The mechanisms responsible are mostly shared by both resistant strains displaying inherently reduced susceptibility and those acquiring resistance during therapy. The molecular mechanisms include altered drug affinity and target abundance, reduced intracellular drug levels caused by efflux pumps, and formation of biofilms. New insights into genetic factors regulating these mechanisms, as well as cellular factors important for stress adaptation, provide a foundation to better understand the emergence of antifungal drug resistance.
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Affiliation(s)
- Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Dominique Sanglard
- University of Lausanne and University Hospital Center, Institute of Microbiology, 1011 Lausanne, Switzerland
| | - Susan J Howard
- University of Liverpool, Sherrington Building, Ashton Street, Liverpool L69 3GE, United Kingdom
| | - P David Rogers
- College of Pharmacy, The University of Tennessee Health Science Center, Memphis, Tennessee 38163
| | - David S Perlin
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey 07103
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150
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Rai MN, Sharma V, Balusu S, Kaur R. An essential role for phosphatidylinositol 3-kinase in the inhibition of phagosomal maturation, intracellular survival and virulence inCandida glabrata. Cell Microbiol 2014; 17:269-87. [DOI: 10.1111/cmi.12364] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 08/29/2014] [Accepted: 09/10/2014] [Indexed: 02/03/2023]
Affiliation(s)
- Maruti Nandan Rai
- Laboratory of Fungal Pathogenesis; Centre for DNA Fingerprinting and Diagnostics; Hyderabad Telangana India
| | - Vandana Sharma
- Laboratory of Fungal Pathogenesis; Centre for DNA Fingerprinting and Diagnostics; Hyderabad Telangana India
| | - Sriram Balusu
- Laboratory of Fungal Pathogenesis; Centre for DNA Fingerprinting and Diagnostics; Hyderabad Telangana India
| | - Rupinder Kaur
- Laboratory of Fungal Pathogenesis; Centre for DNA Fingerprinting and Diagnostics; Hyderabad Telangana India
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