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Huang Y, Zhang Y, Yang S, Lu H, Yu H, Wang X, Jia X, Tang D, Wu L, Huang S, Yang P. Epidemiology of cryptococcal meningitis and fluconazole heteroresistance in Cryptococcus neoformans isolates from a teaching hospital in southwestern China. Microbiol Spectr 2024; 12:e0072524. [PMID: 39007718 DOI: 10.1128/spectrum.00725-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Accepted: 06/30/2024] [Indexed: 07/16/2024] Open
Abstract
Cryptococcal meningitis (CM), a common and serious opportunistic infection mostly caused by Cryptococcus neoformans, is primarily treated with fluconazole. Nevertheless, Cryptococcus neoformans strains that undergo repeated exposure to azoles can gradually acquire heteroresistance to fluconazole. The management of this specific CM infection poses a substantial challenge. Determining a globally accepted definition for fluconazole heteroresistance and developing effective and prompt methods for identifying heteroresistance is of utmost importance. We collected data on the clinical and epidemiological characteristics of patients diagnosed with CM. All the available Cryptococcus neoformans strains isolated from these patients were collected and subjected to antifungal susceptibility testing and evaluation of fluconazole heteroresistance. AIDS was present in 40.5% of the patients, whereas 24.1% did not have any underlying diseases. Patients with chronic diseases or impaired immune systems are susceptible to infection by Cryptococcus neoformans, a fungus that frequently (39.6%, 19/48) shows heteroresistance to fluconazole, as confirmed by population analysis profile (PAP).IMPORTANCEFluconazole heteroresistance poses a significant threat to the efficacy of fluconazole in treating cryptococcal meningitis (CM). Unfortunately, the standard broth microdilution method often misses the subtle percentages of subpopulations exhibiting heteroresistance. While the population analysis profile (PAP) method is esteemed as the gold standard, its time-consuming and labor-intensive nature makes it impractical for routine clinical use. In contrast, the Kirby-Bauer (KB) disk diffusion method offers a simple and effective screening solution. Our study highlights the value of KB over PAP and minimum inhibitory concentration (MIC) by demonstrating that when adjusting the inoculum concentration to 1.0 McFarland and subjecting samples to a 72-hour incubation period at 35°C, the KB method closely mirrors the outcomes of the PAP approach in detecting fluconazole heteroresistance. This optimization of the KB method not only enhances assay efficiency but also provides a blueprint for developing a timely and effective strategy for identifying heteroresistance.
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Affiliation(s)
- Yunfei Huang
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Yongqi Zhang
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Shuangshuang Yang
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Hongling Lu
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Hanbing Yu
- Department of Laboratory Medicine, Fujian Key Clinical Specialty of Laboratory Medicine, Women and Children's Hospital, School of Medicine, Xiamen University, Xiamen, China
| | - Xingyue Wang
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Xiaojiong Jia
- Division of Allergy and Clinical Immunology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Dijiao Tang
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Linhong Wu
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Shifeng Huang
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Ping Yang
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
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Silva I, Miranda IM, Costa-de-Oliveira S. Potential Environmental Reservoirs of Candida auris: A Systematic Review. J Fungi (Basel) 2024; 10:336. [PMID: 38786691 PMCID: PMC11122228 DOI: 10.3390/jof10050336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 04/28/2024] [Accepted: 05/04/2024] [Indexed: 05/25/2024] Open
Abstract
Candida auris, a multidrug-resistant yeast, poses significant challenges in healthcare settings worldwide. Understanding its environmental reservoirs is crucial for effective control strategies. This systematic review aimed to review the literature regarding the natural and environmental reservoirs of C. auris. Following the PRISMA guidelines, published studies until October 2023 were searched in three databases: PubMed, Web of Science, and Scopus. Information regarding the origin, sampling procedure, methods for laboratory identification, and antifungal susceptibility was collected and analyzed. Thirty-three studies published between 2016 and 2023 in 15 countries were included and analyzed. C. auris was detected in various environments, including wastewater treatment plants, hospital patient care surfaces, and natural environments such as salt marshes, sand, seawater, estuaries, apples, and dogs. Detection methods varied, with molecular techniques often used alongside culture. Susceptibility profiles revealed resistance patterns. Phylogenetic studies highlight the potential of environmental strains to influence clinical infections. Despite methodological heterogeneity, this review provides valuable information for future research and highlights the need for standardized sampling and detection protocols to mitigate C. auris transmission.
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Affiliation(s)
- Isabel Silva
- Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal;
| | - Isabel M. Miranda
- Cardiovascular R&D Centre UnIC@RISE, Department of Surgery and Physiology, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal;
| | - Sofia Costa-de-Oliveira
- Division of Microbiology, Department of Pathology, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal
- Center for Health Technology and Services Research—CINTESIS@RISE, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal
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Chen L, Sun BX, Zhao Y, Miao ZY. Molecular Mechanisms and Biological Characteristics of Botrytis cinerea Field Isolate Resistance to Pyrisoxazole in Liaoning Province. PLANT DISEASE 2024; 108:866-876. [PMID: 37682225 DOI: 10.1094/pdis-04-23-0743-re] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/09/2023]
Abstract
Botrytis cinerea is a broad-host-range necrotrophic phytopathogen responsible for serious diseases in leading crops worldwide. The novel sterol 14α-demethylase inhibitor (DMI) pyrisoxazole was recently registered for the control of tomato gray mold caused by B. cinerea in China. One hundred fifty-seven isolates of B. cinerea were collected from tomato greenhouses in 14 cities of Liaoning Province from 2016 to 2021 and examined for sensitivity to pyrisoxazole, with a mean EC50 value of 0.151 μg/ml. Three highly resistant isolates, XD-5, DG-4, and GQ-3, were screened, and the EC50 values were 0.734, 0.606, and 0.639 μg/ml with corresponding resistance factors of 12.88, 10.63, and 11.21, respectively. Compared with field-sensitive strains, the highly resistant isolate XD-5 exhibited fitness defects in traits, including mycelial growth, conidial production, and pathogenicity, but DG-4 and GQ-3 did not experience fitness costs. Positive cross-resistance was observed only between pyrisoxazole and the DMIs tebuconazole and prochloraz but not between pyrisoxazole and the non-DMIs iprodione, procymidone, pyrimethanil, fludioxonil, fluazinam, and fluopyram. Sequence alignment of the CYP51 gene indicated that three point mutations were observed in the highly resistant mutant, namely, V24I in XD-5, G461S in GQ-3, and R464K in DG-4. When exposed to pyrisoxazole, the induced expression levels of the ABC transporter AtrD and MFS transporter Mfs1 increased in the resistant isolates compared with those in the sensitive isolates, whereas the expression level of the CYP51 gene did not change significantly. Molecular docking suggested that the G461S and R464K mutations both led to a decrease in the binding energy between CYP51 and pyrisoxazole, whereas no change was found with the V24I mutation. Thus, two point mutations in the CYP51 protein combined with induced expression of the Mfs1 and AtrD genes appeared to mediate the pyrisoxazole resistance of the highly resistant mutants DG-4 and GQ-3, while the overexpression of the Mfs1 and AtrD genes was responsible for the highly resistant mutant XD-5.
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Affiliation(s)
- Le Chen
- Institute of Plant Protection, Liaoning Academy of Agricultural Sciences, Shenyang 110866, People's Republic of China
| | - Bai-Xin Sun
- Institute of Plant Protection, Liaoning Academy of Agricultural Sciences, Shenyang 110866, People's Republic of China
| | - Yang Zhao
- Institute of Plant Protection, Liaoning Academy of Agricultural Sciences, Shenyang 110866, People's Republic of China
| | - Ze-Yan Miao
- Institute of Plant Protection, Liaoning Academy of Agricultural Sciences, Shenyang 110866, People's Republic of China
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Aguiar TKB, Costa ACM, Neto NAS, Brito DMS, Freitas CDT, Neto JMM, Mesquita FP, Souza PFN. Rise and fall of Caspofungin: the current status of Caspofungin as a treatment for Cryptococcus neoformans infection. Future Microbiol 2024; 19:621-630. [PMID: 38497911 PMCID: PMC11229582 DOI: 10.2217/fmb-2023-0236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 12/12/2023] [Indexed: 03/19/2024] Open
Abstract
Antifungal infections are becoming a major concern to human health due to antimicrobial resistance. Echinocandins have been promising agents against resistant fungal infections, primarily caspofungin, which has a more effective mechanism of action than azoles and polyenes. However, fungi such as Cryptococcus neoformans appear to be inheritably resistant to these drugs, which is concerning due to the high clinical importance of C. neoformans. In this review, we review the history of C. neoformans and the treatments used to treat antifungals over the years, focusing on caspofungin, while highlighting the C. neoformans problem and possible explanations for its inherent resistance.
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Affiliation(s)
- Tawanny KB Aguiar
- Department of Biochemistry & Molecular Biology, Federal University of Ceará, Fortaleza, CE, 60451-970, Brazil
| | - Ana CM Costa
- Department of Biochemistry & Molecular Biology, Federal University of Ceará, Fortaleza, CE, 60451-970, Brazil
| | - Nilton AS Neto
- University of Brasília, Post-Graduation in Molecular Pathology, Darcy Ribeiro Campus, Brasília, DF, 70910-900, Brazil
| | - Daiane MS Brito
- Department of Biochemistry & Molecular Biology, Federal University of Ceará, Fortaleza, CE, 60451-970, Brazil
- Drug Research & Development Center, Department of Physiology & Pharmacology, Federal University of Ceará, Fortaleza, CE, 60430-275, Brazil
| | - Cleverson DT Freitas
- Department of Biochemistry & Molecular Biology, Federal University of Ceará, Fortaleza, CE, 60451-970, Brazil
| | - João MM Neto
- Department of Biochemistry & Molecular Biology, Federal University of Ceará, Fortaleza, CE, 60451-970, Brazil
| | - Felipe P Mesquita
- Drug Research & Development Center, Department of Physiology & Pharmacology, Federal University of Ceará, Fortaleza, CE, 60430-275, Brazil
| | - Pedro FN Souza
- Drug Research & Development Center, Department of Physiology & Pharmacology, Federal University of Ceará, Fortaleza, CE, 60430-275, Brazil
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Meng Y, Ni Y, Li Z, Jiang T, Sun T, Li Y, Gao X, Li H, Suo C, Li C, Yang S, Lan T, Liao G, Liu T, Wang P, Ding C. Interplay between acetylation and ubiquitination of imitation switch chromatin remodeler Isw1 confers multidrug resistance in Cryptococcus neoformans. eLife 2024; 13:e85728. [PMID: 38251723 PMCID: PMC10834027 DOI: 10.7554/elife.85728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 01/21/2024] [Indexed: 01/23/2024] Open
Abstract
Cryptococcus neoformans poses a threat to human health, but anticryptococcal therapy is hampered by the emergence of drug resistance, whose underlying mechanisms remain poorly understood. Herein, we discovered that Isw1, an imitation switch chromatin remodeling ATPase, functions as a master modulator of genes responsible for in vivo and in vitro multidrug resistance in C. neoformans. Cells with the disrupted ISW1 gene exhibited profound resistance to multiple antifungal drugs. Mass spectrometry analysis revealed that Isw1 is both acetylated and ubiquitinated, suggesting that an interplay between these two modification events exists to govern Isw1 function. Mutagenesis studies of acetylation and ubiquitination sites revealed that the acetylation status of Isw1K97 coordinates with its ubiquitination processes at Isw1K113 and Isw1K441 through modulating the interaction between Isw1 and Cdc4, an E3 ligase. Additionally, clinical isolates of C. neoformans overexpressing the degradation-resistant ISW1K97Q allele showed impaired drug-resistant phenotypes. Collectively, our studies revealed a sophisticated acetylation-Isw1-ubiquitination regulation axis that controls multidrug resistance in C. neoformans.
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Affiliation(s)
- Yang Meng
- College of Life and Health Sciences, Northeastern UniversityShenyangChina
| | - Yue Ni
- College of Life and Health Sciences, Northeastern UniversityShenyangChina
| | - Zhuoran Li
- College of Life and Health Sciences, Northeastern UniversityShenyangChina
| | - Tianhang Jiang
- College of Life and Health Sciences, Northeastern UniversityShenyangChina
| | - Tianshu Sun
- Department of Scientific Research, Chinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina
| | - Yanjian Li
- College of Life and Health Sciences, Northeastern UniversityShenyangChina
| | - Xindi Gao
- College of Life and Health Sciences, Northeastern UniversityShenyangChina
| | - Hailong Li
- NHC Key Laboratory of AIDS Immunology, The First Affiliated Hospital of China Medical UniversityShenyangChina
| | - Chenhao Suo
- College of Life and Health Sciences, Northeastern UniversityShenyangChina
| | - Chao Li
- College of Life and Health Sciences, Northeastern UniversityShenyangChina
| | - Sheng Yang
- College of Life and Health Sciences, Northeastern UniversityShenyangChina
| | - Tian Lan
- College of Life and Health Sciences, Northeastern UniversityShenyangChina
| | - Guojian Liao
- College of Pharmaceutical Sciences, Southwest UniversityChongqingChina
| | - Tongbao Liu
- Medical Research Institute, Southwest UniversityChongqingChina
| | - Ping Wang
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center New OrleansNew OrleansUnited States
| | - Chen Ding
- College of Life and Health Sciences, Northeastern UniversityShenyangChina
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Boyce KJ. The Microevolution of Antifungal Drug Resistance in Pathogenic Fungi. Microorganisms 2023; 11:2757. [PMID: 38004768 PMCID: PMC10673521 DOI: 10.3390/microorganisms11112757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 10/30/2023] [Accepted: 10/30/2023] [Indexed: 11/26/2023] Open
Abstract
The mortality rates of invasive fungal infections remain high because of the limited number of antifungal drugs available and antifungal drug resistance, which can rapidly evolve during treatment. Mutations in key resistance genes such as ERG11 were postulated to be the predominant cause of antifungal drug resistance in the clinic. However, recent advances in whole genome sequencing have revealed that there are multiple mechanisms leading to the microevolution of resistance. In many fungal species, resistance can emerge through ERG11-independent mechanisms and through the accumulation of mutations in many genes to generate a polygenic resistance phenotype. In addition, genome sequencing has revealed that full or partial aneuploidy commonly occurs in clinical or microevolved in vitro isolates to confer antifungal resistance. This review will provide an overview of the mutations known to be selected during the adaptive microevolution of antifungal drug resistance and focus on how recent advances in genome sequencing technology have enhanced our understanding of this process.
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Affiliation(s)
- Kylie J Boyce
- School of Science, RMIT University, Melbourne, VIC 3085, Australia
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7
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Rizzo J, Trottier A, Moyrand F, Coppée JY, Maufrais C, Zimbres ACG, Dang TTV, Alanio A, Desnos-Ollivier M, Mouyna I, Péhau-Arnaude G, Commere PH, Novault S, Ene IV, Nimrichter L, Rodrigues ML, Janbon G. Coregulation of extracellular vesicle production and fluconazole susceptibility in Cryptococcus neoformans. mBio 2023; 14:e0087023. [PMID: 37310732 PMCID: PMC10470540 DOI: 10.1128/mbio.00870-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 04/17/2023] [Indexed: 06/14/2023] Open
Abstract
Resistance to fluconazole (FLC), the most widely used antifungal drug, is typically achieved by altering the azole drug target and/or drug efflux pumps. Recent reports have suggested a link between vesicular trafficking and antifungal resistance. Here, we identified novel Cryptococcus neoformans regulators of extracellular vesicle (EV) biogenesis that impact FLC resistance. In particular, the transcription factor Hap2 does not affect the expression of the drug target or efflux pumps, yet it impacts the cellular sterol profile. Subinhibitory FLC concentrations also downregulate EV production. Moreover, in vitro spontaneous FLC-resistant colonies showed altered EV production, and the acquisition of FLC resistance was associated with decreased EV production in clinical isolates. Finally, the reversion of FLC resistance was associated with increased EV production. These data suggest a model in which fungal cells can regulate EV production in place of regulating the drug target gene expression as a first line of defense against antifungal assault in this fungal pathogen. IMPORTANCE Extracellular vesicles (EVs) are membrane-enveloped particles that are released by cells into the extracellular space. Fungal EVs can mediate community interactions and biofilm formation, but their functions remain poorly understood. Here, we report the identification of the first regulators of EV production in the major fungal pathogen Cryptococcus neoformans. Surprisingly, we uncover a novel role of EVs in modulating antifungal drug resistance. Disruption of EV production was associated with altered lipid composition and changes in fluconazole susceptibility. Spontaneous azole-resistant mutants were deficient in EV production, while loss of resistance restored initial EV production levels. These findings were recapitulated in C. neoformans clinical isolates, indicating that azole resistance and EV production are coregulated in diverse strains. Our study reveals a new mechanism of drug resistance in which cells adapt to azole stress by modulating EV production.
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Affiliation(s)
- Juliana Rizzo
- Institut Pasteur, Université Paris Cité, Unité Biologie des ARN des Pathogènes Fongiques, Paris, France
- Instituto de Microbiologia Paulo de Góes (IMPG), Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Adèle Trottier
- Institut Pasteur, Université Paris Cité, Unité Biologie des ARN des Pathogènes Fongiques, Paris, France
| | - Frédérique Moyrand
- Institut Pasteur, Université Paris Cité, Unité Biologie des ARN des Pathogènes Fongiques, Paris, France
| | - Jean-Yves Coppée
- Institut Pasteur, Université Paris Cité, Unité Biologie des ARN des Pathogènes Fongiques, Paris, France
| | - Corinne Maufrais
- Institut Pasteur, Université Paris Cité, Unité Biologie des ARN des Pathogènes Fongiques, Paris, France
- Institut Pasteur, Université Paris Cité, USR 3756 IP CNRS, HUB Bioinformatique et Biostatistique, Paris, France
| | - Ana Claudia G. Zimbres
- Instituto de Microbiologia Paulo de Góes (IMPG), Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Thi Tuong Vi Dang
- Institut Pasteur, Université Paris Cité, Unité Biologie des ARN des Pathogènes Fongiques, Paris, France
| | - Alexandre Alanio
- Institut Pasteur, Université Paris Cité, Centre National de Référence Mycoses Invasives et Antifongiques, Groupe de recherche Mycologie Translationnelle, Département de Mycologie, Paris, France
- Laboratoire de parasitologie-mycologie, AP-HP, Hôpital Saint-Louis, Paris, France
| | - Marie Desnos-Ollivier
- Institut Pasteur, Université Paris Cité, Centre National de Référence Mycoses Invasives et Antifongiques, Groupe de recherche Mycologie Translationnelle, Département de Mycologie, Paris, France
| | - Isabelle Mouyna
- Institut Pasteur, Université Paris Cité, Unité Biologie des ARN des Pathogènes Fongiques, Paris, France
| | - Gérard Péhau-Arnaude
- Institut Pasteur, Université Paris Cité, Plateforme de Bio-Imagerie Ultrastructurale, Paris, France
| | - Pierre-Henri Commere
- Institut Pasteur, Université Paris Cité, Cytometry and Biomarkers, Paris, France
| | - Sophie Novault
- Institut Pasteur, Université Paris Cité, Cytometry and Biomarkers, Paris, France
| | - Iuliana V. Ene
- Institut Pasteur, Université Paris Cité, Fungal Heterogeneity Group, Paris, France
| | - Leonardo Nimrichter
- Instituto de Microbiologia Paulo de Góes (IMPG), Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Marcio L. Rodrigues
- Instituto de Microbiologia Paulo de Góes (IMPG), Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- Instituto Carlos Chagas, Fundação Oswaldo Cruz (FIOCRUZ), Curitiba, Brazil
| | - Guilhem Janbon
- Institut Pasteur, Université Paris Cité, Unité Biologie des ARN des Pathogènes Fongiques, Paris, France
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Carvajal SK, Melendres J, Escandón P, Firacative C. Reduced Susceptibility to Azoles in Cryptococcus gattii Correlates with the Substitution R258L in a Substrate Recognition Site of the Lanosterol 14-α-Demethylase. Microbiol Spectr 2023; 11:e0140323. [PMID: 37341584 PMCID: PMC10434158 DOI: 10.1128/spectrum.01403-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 06/01/2023] [Indexed: 06/22/2023] Open
Abstract
Cryptococcus neoformans and Cryptococcus gattii cause cryptococcosis, a life-threatening fungal infection affecting mostly immunocompromised patients. In fact, cryptococcal meningitis accounts for about 19% of AIDS-related deaths in the world. Because of long-term azole therapies to treat this mycosis, resistance to fluconazole leading to treatment failure and poor prognosis has long been reported for both fungal species. Among the mechanisms implicated in resistance to azoles, mutations in the ERG11 gene, encoding the azole target enzyme lanosterol 14-α-demethylase, have been described. This study aimed to establish the amino acid composition of ERG11 of Colombian clinical isolates of C. neoformans and C. gattii and to correlate any possible substitution with the in vitro susceptibility profile of the isolates to fluconazole, voriconazole, and itraconazole. Antifungal susceptibility testing results showed that C. gattii isolates are less susceptible to azoles than C. neoformans isolates, which could correlate with differences in the amino acid composition and structure of ERG11 of each species. In addition, in a C. gattii isolate with high MICs for fluconazole (64 μg/mL) and voriconazole (1 μg/mL), a G973T mutation resulting in the substitution R258L, located in substrate recognition site 3 of ERG11, was identified. This finding suggests the association of the newly reported substitution with the azole resistance phenotype in C. gattii. Further investigations are needed to determine the exact role that R258L plays in the decreased susceptibility to fluconazole and voriconazole, as well as to determine the participation of additional mechanisms of resistance to azole drugs. IMPORTANCE The fungal species Cryptococcus neoformans and C. gattii are human pathogens for which drug resistance or other treatment and management challenges exist. Here, we report differential susceptibility to azoles among both species, with some isolates displaying resistant phenotypes. Azoles are among the most commonly used drugs to treat cryptococcal infections. Our findings underscore the necessity of testing antifungal susceptibility in the clinical setting in order to assist patient management and beneficial outcomes. In addition, we report an amino acid change in the sequence of the target protein of azoles, which suggests that this change might be implicated in resistance to these drugs. Identifying and understanding possible mechanisms that affect drug affinity will eventually aid the design of new drugs that overcome the global growing concern of antifungal resistance.
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Affiliation(s)
| | - Javier Melendres
- Studies in Translational Microbiology and Emerging Diseases (MICROS) Research Group, School of Medicine and Health Sciences, Universidad del Rosario, Bogotá, Colombia
| | - Patricia Escandón
- Group of Microbiology, Instituto Nacional de Salud, Bogotá, Colombia
| | - Carolina Firacative
- Studies in Translational Microbiology and Emerging Diseases (MICROS) Research Group, School of Medicine and Health Sciences, Universidad del Rosario, Bogotá, Colombia
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9
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Osset-Trénor P, Pascual-Ahuir A, Proft M. Fungal Drug Response and Antimicrobial Resistance. J Fungi (Basel) 2023; 9:jof9050565. [PMID: 37233275 DOI: 10.3390/jof9050565] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 04/27/2023] [Accepted: 05/12/2023] [Indexed: 05/27/2023] Open
Abstract
Antifungal resistance is a growing concern as it poses a significant threat to public health. Fungal infections are a significant cause of morbidity and mortality, especially in immunocompromised individuals. The limited number of antifungal agents and the emergence of resistance have led to a critical need to understand the mechanisms of antifungal drug resistance. This review provides an overview of the importance of antifungal resistance, the classes of antifungal agents, and their mode of action. It highlights the molecular mechanisms of antifungal drug resistance, including alterations in drug modification, activation, and availability. In addition, the review discusses the response to drugs via the regulation of multidrug efflux systems and antifungal drug-target interactions. We emphasize the importance of understanding the molecular mechanisms of antifungal drug resistance to develop effective strategies to combat the emergence of resistance and highlight the need for continued research to identify new targets for antifungal drug development and explore alternative therapeutic options to overcome resistance. Overall, an understanding of antifungal drug resistance and its mechanisms will be indispensable for the field of antifungal drug development and clinical management of fungal infections.
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Affiliation(s)
- Paloma Osset-Trénor
- Department of Biotechnology, Instituto de Biología Molecular y Celular de Plantas IBMCP, Universidad Politécnica de Valencia, 46022 Valencia, Spain
| | - Amparo Pascual-Ahuir
- Department of Biotechnology, Instituto de Biología Molecular y Celular de Plantas IBMCP, Universidad Politécnica de Valencia, 46022 Valencia, Spain
| | - Markus Proft
- Department of Molecular and Cellular Pathology and Therapy, Instituto de Biomedicina de Valencia IBV-CSIC, Consejo Superior de Investigaciones Científicas CSIC, 46010 Valencia, Spain
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Bombassaro A, Spruijtenburg B, Medeiros F, Jacomel Favoreto de Souza Lima B, Ballardin LB, Farias MRD, Vicente VA, de Queiroz‐Telles F, Meis JF, de Groot T. Genotyping and antifungal susceptibility testing of
Sporothrix brasiliensis
isolates from Southern Brazil. Mycoses 2023. [DOI: 10.1111/myc.13584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 03/08/2023] [Accepted: 03/15/2023] [Indexed: 03/29/2023]
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11
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Deng H, Song J, Huang Y, Yang C, Zang X, Zhou Y, Li H, Dai B, Xue X. Combating increased antifungal drug resistance in Cryptococcus, what should we do in the future? Acta Biochim Biophys Sin (Shanghai) 2023; 55:540-547. [PMID: 36815374 DOI: 10.3724/abbs.2023011] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Few therapeutic drugs and increased drug resistance have aggravated the current treatment difficulties of Cryptococcus in recent years. To better understand the antifungal drug resistance mechanism and treatment strategy of cryptococcosis. In this review, by combining the fundamental features of Cryptococcus reproduction leading to changes in its genome, we review recent research into the mechanism of four current anti-cryptococcal agents, coupled with new therapeutic strategies and the application of advanced technologies WGS and CRISPR-Cas9 in this field, hoping to provide a broad idea for the future clinical therapy of cryptococcosis.
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Affiliation(s)
- Hengyu Deng
- Affiliated Hospital of Weifang Medical University, School of Clinical Medicine, Weifang Medical University, Weifang 261053, China
| | - Jialin Song
- Affiliated Hospital of Weifang Medical University, School of Clinical Medicine, Weifang Medical University, Weifang 261053, China
| | - Yemei Huang
- Department of Respiratory and Critical Care, Beijing Shijitan Hospital, Capital Medical University; Peking University Ninth School of Clinical Medicine, Beijing 100089, China
| | - Chen Yang
- Department of Laboratory Medicine, the First Medical Centre, Chinese PLA General Hospital, Beijing 100853, China
| | - Xuelei Zang
- Department of Respiratory and Critical Care, Beijing Shijitan Hospital, Capital Medical University; Peking University Ninth School of Clinical Medicine, Beijing 100089, China
| | - Yangyu Zhou
- Department of Respiratory and Critical Care, Beijing Shijitan Hospital, Capital Medical University; Peking University Ninth School of Clinical Medicine, Beijing 100089, China
| | - Hongli Li
- Affiliated Hospital of Weifang Medical University, School of Clinical Medicine, Weifang Medical University, Weifang 261053, China
| | - Bin Dai
- Department of Respiratory and Critical Care, Beijing Shijitan Hospital, Capital Medical University; Peking University Ninth School of Clinical Medicine, Beijing 100089, China
| | - Xinying Xue
- Affiliated Hospital of Weifang Medical University, School of Clinical Medicine, Weifang Medical University, Weifang 261053, China.,Department of Respiratory and Critical Care, Beijing Shijitan Hospital, Capital Medical University; Peking University Ninth School of Clinical Medicine, Beijing 100089, China
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12
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Martins-Santana L, Rezende CP, Rossi A, Martinez-Rossi NM, Almeida F. Addressing Microbial Resistance Worldwide: Challenges over Controlling Life-Threatening Fungal Infections. Pathogens 2023; 12:pathogens12020293. [PMID: 36839565 PMCID: PMC9961291 DOI: 10.3390/pathogens12020293] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 02/02/2023] [Accepted: 02/03/2023] [Indexed: 02/12/2023] Open
Abstract
Fungal infections are a serious global concern because of their ability to spread and colonize host tissues in immunocompromised individuals. Such infections have been frequently reported worldwide and are currently gaining clinical research relevance owing to their resistant character, representing a bottleneck in treating affected people. Resistant fungi are an emergent public health threat. The upsurge of such pathogens has led to new research toward unraveling the destructive potential evoked by these species. Some fungi-grouped into Candida, Aspergillus, and Cryptococcus-are causative agents of severe and systemic infections. They are associated with high mortality rates and have recently been described as sources of coinfection in COVID-hospitalized patients. Despite the efforts to elucidate the challenges of colonization, dissemination, and infection severity, the immunopathogenesis of fungal diseases remains a pivotal characteristic in fungal burden elimination. The struggle between the host immune system and the physiological strategies of the fungi to maintain cellular viability is complex. In this brief review, we highlight the relevance of drug resistance phenotypes in fungi of clinical significance, taking into consideration their physiopathology and how the scientific community could orchestrate their efforts to avoid fungal infection dissemination and deaths.
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Affiliation(s)
- Leonardo Martins-Santana
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14040-900, Brazil
| | - Caroline Patini Rezende
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14040-900, Brazil
| | - Antonio Rossi
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14040-900, Brazil
| | - Nilce Maria Martinez-Rossi
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14040-900, Brazil
| | - Fausto Almeida
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14040-900, Brazil
- Correspondence:
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13
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Carvajal SK, Vargas-Casanova Y, Pineda-Castañeda HM, García-Castañeda JE, Rivera-Monroy ZJ, Parra-Giraldo CM. In Vitro Antifungal Activity of Chimeric Peptides Derived from Bovine Lactoferricin and Buforin II against Cryptococcus neoformans var. grubii. Antibiotics (Basel) 2022; 11:antibiotics11121819. [PMID: 36551475 PMCID: PMC9774238 DOI: 10.3390/antibiotics11121819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 12/09/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Cryptococcosis is associated with high rates of morbidity and mortality. The limited number of antifungal agents, their toxicity, and the difficulty of these molecules in crossing the blood-brain barrier have made the exploration of new therapeutic candidates against Cryptococcus neoformans a priority task. To optimize the antimicrobial functionality and improve the physicochemical properties of AMPs, chemical strategies include combinations of peptide fragments into one. This study aimed to evaluate the binding of the minimum activity motif of bovine lactoferricin (LfcinB) and buforin II (BFII) against C. neoformans var. grubii. The antifungal activity against these chimeras was evaluated against (i) the reference strain H99, (ii) three Colombian clinical strains, and (iii) eleven mutant strains, with the aim of evaluating the possible antifungal target. We found high activity against these strains, with a MIC between 6.25 and 12.5 µg/mL. Studies were carried out to evaluate the effect of the combination of fluconazole treatments, finding a synergistic effect. Finally, when fibroblast cells were treated with 12.5 µg/mL of the chimeras, a viability of more than 65% was found. The results obtained in this study identify these chimeras as potential antifungal molecules for future therapeutic applications against cryptococcosis.
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Affiliation(s)
- Silvia Katherine Carvajal
- Unidad de Proteómica y Micosis Humanas, Grupo de Enfermedades Infecciosas, Departamento de Microbiología, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá D.C. 110231, Colombia
| | - Yerly Vargas-Casanova
- Unidad de Proteómica y Micosis Humanas, Grupo de Enfermedades Infecciosas, Departamento de Microbiología, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá D.C. 110231, Colombia
| | - Héctor Manuel Pineda-Castañeda
- Chemistry Department, Universidad Nacional de Colombia, Carrera 45 No. 26–85, Building 451, Office 409, Bogotá D.C. 111321, Colombia
| | - Javier Eduardo García-Castañeda
- Pharmacy Department, Universidad Nacional de Colombia, Bogotá Carrera 45 No. 26–85, Building 450, Bogotá D.C. 111321, Colombia
| | - Zuly Jenny Rivera-Monroy
- Chemistry Department, Universidad Nacional de Colombia, Carrera 45 No. 26–85, Building 451, Office 409, Bogotá D.C. 111321, Colombia
| | - Claudia Marcela Parra-Giraldo
- Unidad de Proteómica y Micosis Humanas, Grupo de Enfermedades Infecciosas, Departamento de Microbiología, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá D.C. 110231, Colombia
- Correspondence: ; Tel.: +57-1-3208320 (ext. 4305)
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14
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Ruma YN, Keniya MV, Monk BC. Exploring Cryptococcus neoformans CYP51 and Its Cognate Reductase as a Drug Target. J Fungi (Basel) 2022; 8:jof8121256. [PMID: 36547589 PMCID: PMC9785471 DOI: 10.3390/jof8121256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 11/23/2022] [Accepted: 11/24/2022] [Indexed: 11/30/2022] Open
Abstract
Cryptococcus remains a leading cause of invasive fungal infections in immunocompromised people. Resistance to azole drugs has imposed a further challenge to the effective treatment of such infections. In this study, the functional expression of full-length hexahistidine-tagged Cryptococcus neoformans CYP51 (CnCYP51-6×His), with or without its cognate hexahistidine-tagged NADPH-cytochrome P450 reductase (CnCPR-6×His), in a Saccharomyces cerevisiae host system has been used to characterise these enzymes. The heterologous expression of CnCYP51-6×His complemented deletion of the host CYP51 and conferred increased susceptibility to both short-tailed and long-tailed azole drugs. In addition, co-expression of CnCPR-6×His decreased susceptibility 2- to 4-fold for short-tailed but not long-tailed azoles. Type 2 binding of azoles to CnCYP51-6×His and assay of NADPH cytochrome P450 reductase activity confirmed that the heterologously expressed CnCYP51 and CnCPR are functional. The constructs have potential as screening tools and use in structure-directed antifungal discovery.
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Affiliation(s)
- Yasmeen N. Ruma
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin 9016, New Zealand
| | - Mikhail V. Keniya
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin 9016, New Zealand
- Hackensack Meridian Health Center for Discovery and Innovation, Nutley, NJ 07110, USA
| | - Brian C. Monk
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin 9016, New Zealand
- Correspondence:
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15
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Zhang J, Wang Z, Chen Y, Zhou Z, Yang Q, Fu Y, Zhao F, Li X, Chen Q, Fang L, Jiang Y, Yu Y. Antifungal susceptibility and molecular characteristics of Cryptococcus spp. based on whole-genome sequencing in Zhejiang Province, China. Front Microbiol 2022; 13:991703. [PMID: 36466641 PMCID: PMC9712201 DOI: 10.3389/fmicb.2022.991703] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 10/31/2022] [Indexed: 06/05/2024] Open
Abstract
Cryptococcus spp. is a complex species that often causes cryptococcosis, which is one of the most common opportunistic infections in adults living with HIV and has very high morbidity and mortality rates. This study aimed to investigate the antifungal susceptibility profiles and epidemiological characteristics of the Cryptococcus neoformans species complex (CNSC) and the Cryptococcus gattii species complex (CGSC) in Zhejiang Province, China. A total of 177 CNSC and 3 CGSC isolates were collected, and antifungal susceptibility was tested by FUNGUS 3 and verified with an E-test. Moreover, multiple classification methods and genomic analyses were performed. The majority of the isolates (96.11%) were C. neoformans (formerly C. neoformans var. grubii) (ST5-VNI-A-α). Our study highlights that most of the patients with cryptococcosis were non-HIV patients in China, and nearly half of them did not have underlying diseases that led to immune insufficiency. Most of the Cryptococcus spp. isolates in this study were sensitive to common antifungal drugs. Two 5-flucytosine (5-FC)-resistant strains were identified, and FUR1 mutation was detected in the 5-FC-resistant isolates. Typing based on whole-genome sequencing (WGS) showed better discrimination than that achieved with multilocus sequence typing (MLST) and indicated a clear population structure. A phylogenetic analysis based on WGS included more genomic information than traditional classification methods.
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Affiliation(s)
- Junli Zhang
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Zhengan Wang
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Yan Chen
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Zhihui Zhou
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Qing Yang
- Department of Clinical Laboratory, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Ying Fu
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Department of Clinical Laboratory, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Feng Zhao
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- Department of Clinical Laboratory, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xi Li
- Department of Clinical Laboratory, Zhejiang Provincial People's Hospital, Hangzhou, China
| | - Qiong Chen
- Department of Clinical Laboratory, Affiliated Hangzhou First People’s Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Li Fang
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Yan Jiang
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Yunsong Yu
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
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16
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Celia-Sanchez BN, Mangum B, Brewer M, Momany M. Analysis of Cyp51 protein sequences shows 4 major Cyp51 gene family groups across fungi. G3 (BETHESDA, MD.) 2022; 12:jkac249. [PMID: 36130263 PMCID: PMC9635630 DOI: 10.1093/g3journal/jkac249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 09/07/2022] [Indexed: 06/15/2023]
Abstract
Azole drugs target fungal sterol biosynthesis and are used to treat millions of human fungal infections each year. Resistance to azole drugs has emerged in multiple fungal pathogens including Candida albicans, Cryptococcus neoformans, Histoplasma capsulatum, and Aspergillus fumigatus. The most well-studied resistance mechanism in A. fumigatus arises from missense mutations in the coding sequence combined with a tandem repeat in the promoter of cyp51A, which encodes a cytochrome P450 enzyme in the fungal sterol biosynthesis pathway. Filamentous members of Ascomycota such as A. fumigatus have either 1 or 2 of 3 Cyp51 paralogs (Cyp51A, Cyp51B, and Cyp51C). Most previous research in A. fumigatus has focused on Cyp51A due to its role in azole resistance. We used the A. fumigatus Cyp51A protein sequence as the query in database searches to identify Cyp51 proteins across fungi. We found 435 Cyp51 proteins in 295 species spanning from early-diverging fungi (Blastocladiomycota, Chytridiomycota, Zoopagomycota, and Mucormycota) to late-diverging fungi (Ascomycota and Basidiomycota). We found these sequences formed 4 major Cyp51 groups: Cyp51, Cyp51A, Cyp51B, and Cyp51C. Surprisingly, we found all filamentous Ascomycota had a Cyp51B paralog, while only 50% had a Cyp51A paralog. We created maximum likelihood trees to investigate the evolution of Cyp51 in fungi. Our results suggest Cyp51 is present in all fungi with 3 paralogs emerging in Pezizomycotina, including Cyp51C which appears to have diverged from the progenitor of the Cyp51A and Cyp51B groups.
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Affiliation(s)
| | - Brandon Mangum
- Department of Plant Biology, University of Georgia, Athens, GA 30606, USA
| | - Marin Brewer
- Department of Plant Pathology, University of Georgia, Athens, GA 30606, USA
| | - Michelle Momany
- Department of Plant Biology, University of Georgia, Athens, GA 30606, USA
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17
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Kukurudz RJ, Chapel M, Wonitowy Q, Adamu Bukari AR, Sidney B, Sierhuis R, Gerstein AC. Acquisition of cross-azole tolerance and aneuploidy in Candida albicans strains evolved to posaconazole. G3 (BETHESDA, MD.) 2022; 12:jkac156. [PMID: 35881695 PMCID: PMC9434289 DOI: 10.1093/g3journal/jkac156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 06/13/2022] [Indexed: 12/30/2022]
Abstract
A number of in vitro studies have examined the acquisition of drug resistance to the triazole fluconazole, a first-line treatment for many Candida infections. Much less is known about posaconazole, a newer triazole. We conducted the first in vitro experimental evolution of replicates from 8 diverse strains of Candida albicans in a high level of the fungistatic drug posaconazole. Approximately half of the 132 evolved replicates survived 50 generations of evolution, biased toward some of the strain backgrounds. We found that although increases in drug resistance were rare, increases in drug tolerance (the slow growth of a subpopulation of cells in a level of drug above the resistance level) were common across strains. We also found that adaptation to posaconazole resulted in widespread cross-tolerance to other azole drugs. Widespread aneuploidy was observed in evolved replicates from some strain backgrounds. Trisomy of at least one of chromosomes 3, 6, and R was identified in 11 of 12 whole-genome sequenced evolved SC5314 replicates. These findings document rampant evolved cross-tolerance among triazoles and highlight that increases in drug tolerance can evolve independently of drug resistance in a diversity of C. albicans strain backgrounds.
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Affiliation(s)
- Rebekah J Kukurudz
- Department of Microbiology, The University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Madison Chapel
- Department of Microbiology, The University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Quinn Wonitowy
- Department of Microbiology, The University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | | | - Brooke Sidney
- Department of Microbiology, The University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Riley Sierhuis
- Department of Microbiology, The University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Aleeza C Gerstein
- Department of Microbiology, The University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- Department of Statistics, The University of Manitoba, Winnipeg, MB R3T 2N2, Canada
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18
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Lin K, Lai Y, Lin Y, Ho M, Chen Y, Chung W. Antifungal Susceptibility of the Clinical and Environmental Strains of
Cryptococcus gattii sensu lato
in Taiwan. Mycoses 2022; 66:13-24. [DOI: 10.1111/myc.13520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 08/11/2022] [Accepted: 08/15/2022] [Indexed: 11/28/2022]
Affiliation(s)
- Kuo‐Hsi Lin
- Tungs’ Taichung MetroHarbor Hospital Taichung Taiwan
- National Chung Hsing University Taichung Taiwan
| | - Yi‐Chyi Lai
- Chung Shan Medical University Taichung Taiwan
| | - Yi‐Pei Lin
- Tungs’ Taichung MetroHarbor Hospital Taichung Taiwan
| | - Mao‐Wang Ho
- China Medical University Hospital Taichung Taiwan
| | | | - Wen‐Hsin Chung
- National Chung Hsing University Taichung Taiwan
- Innovation and Development center of sustainable Agriculture (IDCSA), Taichung Taiwan
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19
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An Atypical ABC Transporter Is Involved in Antifungal Resistance and Host Interactions in the Pathogenic Fungus Cryptococcus neoformans. mBio 2022; 13:e0153922. [PMID: 35726920 PMCID: PMC9426558 DOI: 10.1128/mbio.01539-22] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
ATP-binding cassette (ABC) transporters represent one of the largest protein superfamilies. Functionally diverse, ABC transporters have been implicated in many aspects of microbial physiology. The genome of the human fungal pathogen Cryptococcus neoformans encodes 54 putative ABC transporters and most of them remain uncharacterized. In a previous genetic screen for fungal regulators of phagocytosis, we identified an uncharacterized gene, CNAG_06909, that modulates host interactions. This gene encoded a half-size ABC transporter of the PDR-type, and phenotypic studies of a strain with this gene deleted revealed an altered antifungal susceptibility profile, including hypersensitivity to fluconazole (FLC). This gene, which we named PDR6, localized to the endoplasmic reticulum (ER) and plasma membrane (PM), and when absent, less ergosterol was observed in the PM. Additionally, we observed that the pdr6Δ strain displayed a reduction in secreted polysaccharide capsular material. These changes to the cellular surface may explain the observed increased uptake by macrophages and the reduced intracellular survival. Finally, studies in mice demonstrated that Pdr6 function was required for the normal progression of cryptococcal infection. Taken together, this study demonstrates a novel dual role for PDR transporters in C. neoformans, which could represent a potential target for antifungal therapeutics. Furthermore, the atypical half-size transporter encoded by PDR6 is conserved in many fungal pathogens, but absent in model nonpathogenic fungi. Hence, this study provided a function for this unique group of fungal half-size PDR transporters that, although conserved, remain largely understudied.
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20
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Atim PB, Meya DB, Gerlach ES, Muhanguzi D, Male A, Kanamwanji B, Nielsen K. Lack of Association between Fluconazole Susceptibility and ERG11 Nucleotide Polymorphisms in Cryptococcus neoformans Clinical Isolates from Uganda. J Fungi (Basel) 2022; 8:508. [PMID: 35628763 PMCID: PMC9145384 DOI: 10.3390/jof8050508] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 05/04/2022] [Accepted: 05/10/2022] [Indexed: 11/22/2022] Open
Abstract
Fluconazole is the drug of choice for cryptococcal meningitis (CM) monoprophylaxis in resource-limited settings such as Uganda. Emerging fluconazole resistance linked to mutations in the Cryptococcus neoformansERG11 gene (CYP51) has been observed in clinical isolates. Currently, the single nucleotide polymorphisms [SNPs] in the Cryptococcus spp. ERG11 gene that could be responsible for fluconazole resistance are poorly characterized within Ugandan C. neoformans clinical isolates. If available, this information would be useful in the management of cryptococcosis among HIV patients. This cross-sectional study investigates the SNPs present in the coding region of the C. neoformansERG11 gene to determine the relationship between the SNPs identified and fluconazole susceptibility of the clinical isolates. 310 C. neoformans isolates recovered from the Cerebrospinal Fluid (CSF) of patients with HIV and cryptococcal meningitis were examined. The fluconazole half-maximal inhibitory concentrations (IC50 range: 0.25−32 μg/mL) was determined using the microbroth dilution method. A total of 56.1% of the isolates had low IC50 values of <8 μg/mL while 43.9% had high IC50 values ≥ 8 μg/mL. We amplified and sequenced 600 bp of the ERG11 coding sequence from 40 of the clinical isolates. Novel synonymous and 2 missense mutations, S460T and A457V, were identified in the ERG11 gene. The identified SNPs were not associated with differences in fluconazole IC50 values in vitro (p = 0.179).
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Affiliation(s)
| | - David B. Meya
- Infectious Diseases Institute, Kampala P.O. Box 22418, Uganda;
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN 55455, USA; (E.S.G.); (K.N.)
| | - Elliot S. Gerlach
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN 55455, USA; (E.S.G.); (K.N.)
| | - Dennis Muhanguzi
- College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala P.O. Box 7062, Uganda;
| | - Allan Male
- International Centre for Tropical Agriculture (CIAT)—Uganda, Kampala P.O. Box 6247, Uganda;
| | - Benedict Kanamwanji
- National Microbiology Reference Laboratory (NMRL), Kampala P.O. Box 7272, Uganda;
| | - Kirsten Nielsen
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN 55455, USA; (E.S.G.); (K.N.)
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21
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Characterisation of Candida parapsilosis CYP51 as a Drug Target Using Saccharomyces cerevisiae as Host. J Fungi (Basel) 2022; 8:jof8010069. [PMID: 35050009 PMCID: PMC8781857 DOI: 10.3390/jof8010069] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 01/04/2022] [Accepted: 01/07/2022] [Indexed: 02/04/2023] Open
Abstract
The fungal cytochrome P450 lanosterol 14α-demethylase (CYP51) is required for the biosynthesis of fungal-specific ergosterol and is the target of azole antifungal drugs. Despite proven success as a clinical target for azole antifungals, there is an urgent need to develop next-generation antifungals that target CYP51 to overcome the resistance of pathogenic fungi to existing azole drugs, toxic adverse reactions and drug interactions due to human drug-metabolizing CYPs. Candida parapsilosis is a readily transmitted opportunistic fungal pathogen that causes candidiasis in health care environments. In this study, we have characterised wild type C. parapsilosis CYP51 and its clinically significant, resistance-causing point mutation Y132F by expressing these enzymes in a Saccharomyces cerevisiae host system. In some cases, the enzymes were co-expressed with their cognate NADPH-cytochrome P450 reductase (CPR). Constitutive expression of CpCYP51 Y132F conferred a 10- to 12-fold resistance to fluconazole and voriconazole, reduced to ~6-fold resistance for the tetrazoles VT-1161 and VT-1129, but did not confer resistance to the long-tailed triazoles. Susceptibilities were unchanged in the case of CpCPR co-expression. Type II binding spectra showed tight triazole and tetrazole binding by affinity-purified recombinant CpCYP51. We report the X-ray crystal structure of ScCYP51 in complex with VT-1129 obtained at a resolution of 2.1 Å. Structural analysis of azole—enzyme interactions and functional studies of recombinant CYP51 from C. parapsilosis have improved understanding of their susceptibility to azole drugs and will help advance structure-directed antifungal discovery.
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22
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Rogers TR, Verweij PE, Castanheira M, Dannaoui E, White PL, Arendrup MC. OUP accepted manuscript. J Antimicrob Chemother 2022; 77:2053-2073. [PMID: 35703391 PMCID: PMC9333407 DOI: 10.1093/jac/dkac161] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The increasing incidence and changing epidemiology of invasive fungal infections continue to present many challenges to their effective management. The repertoire of antifungal drugs available for treatment is still limited although there are new antifungals on the horizon. Successful treatment of invasive mycoses is dependent on a mix of pathogen-, host- and antifungal drug-related factors. Laboratories need to be adept at detection of fungal pathogens in clinical samples in order to effectively guide treatment by identifying isolates with acquired drug resistance. While there are international guidelines on how to conduct in vitro antifungal susceptibility testing, these are not performed as widely as for bacterial pathogens. Furthermore, fungi generally are recovered in cultures more slowly than bacteria, and often cannot be cultured in the laboratory. Therefore, non-culture-based methods, including molecular tests, to detect fungi in clinical specimens are increasingly important in patient management and are becoming more reliable as technology improves. Molecular methods can also be used for detection of target gene mutations or other mechanisms that predict antifungal drug resistance. This review addresses acquired antifungal drug resistance in the principal human fungal pathogens and describes known resistance mechanisms and what in-house and commercial tools are available for their detection. It is emphasized that this approach should be complementary to culture-based susceptibility testing, given the range of mutations, resistance mechanisms and target genes that may be present in clinical isolates, but may not be included in current molecular assays.
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Affiliation(s)
| | | | | | | | | | - Maiken Cavling Arendrup
- Unit of Mycology, Statens Serum Institut, Copenhagen, Denmark
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
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23
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Albehaijani SHI, Macreadie I, Morrissey CO, Boyce KJ. OUP accepted manuscript. JAC Antimicrob Resist 2022; 4:dlac033. [PMID: 35402912 PMCID: PMC8986524 DOI: 10.1093/jacamr/dlac033] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 03/08/2022] [Indexed: 12/02/2022] Open
Abstract
Background Fungal infections are common life-threatening diseases amongst immunodeficient individuals. Invasive fungal disease is commonly treated with an azole antifungal agent, resulting in selection pressure and the emergence of drug resistance. Antifungal resistance is associated with higher mortality rates and treatment failure, making the current clinical management of fungal disease very challenging. Clinical isolates from a variety of fungi have been shown to contain mutations in the MSH2 gene, encoding a component of the DNA mismatch repair pathway. Mutation of MSH2 results in an elevated mutation rate that can increase the opportunity for selectively advantageous mutations to occur, accelerating the development of antifungal resistance. Objectives To characterize the molecular mechanisms causing the microevolutionary emergence of antifungal resistance in msh2 mismatch repair mutants of Cryptococcus neoformans. Methods The mechanisms resulting in the emergence of antifungal resistance were investigated using WGS, characterization of deletion mutants and measuring ploidy changes. Results The genomes of resistant strains did not possess mutations in ERG11 or other genes of the ergosterol biosynthesis pathway. Antifungal resistance was due to small contributions from mutations in many genes. MSH2 does not directly affect ploidy changes. Conclusions This study provides evidence that resistance to fluconazole can evolve independently of ERG11 mutations. A common microevolutionary route to the emergence of antifungal resistance involves the accumulation of mutations that alter stress signalling, cellular efflux, membrane trafficking, epigenetic modification and aneuploidy. This complex pattern of microevolution highlights the significant challenges posed both to diagnosis and treatment of drug-resistant fungal pathogens.
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Affiliation(s)
| | - Ian Macreadie
- School of Science, RMIT University, Melbourne, VIC, Australia
| | - C. Orla Morrissey
- Department of Infectious Diseases, Alfred Health and Monash University, Melbourne, VIC, Australia
| | - Kylie J. Boyce
- School of Science, RMIT University, Melbourne, VIC, Australia
- Corresponding author. E-mail:
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Adaptation to Fluconazole via Aneuploidy Enables Cross-Adaptation to Amphotericin B and Flucytosine in Cryptococcus neoformans. Microbiol Spectr 2021; 9:e0072321. [PMID: 34585947 PMCID: PMC8557924 DOI: 10.1128/spectrum.00723-21] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The high morbidity and mortality of cryptococcal meningitis is due to the limited range of therapeutic options: only three classes of antifungal drugs are available (polyenes [amphotericin B], azoles [fluconazole], and pyrimidine analogues [flucytosine]). Fluconazole is the most widely used antifungal drug in sub-Saharan Africa, where cryptococcal meningitis is a major cause of death in patients infected with HIV. In this study, we found that exposure to fluconazole, even for short times (48 h) at subinhibitory concentrations, drove rapid adaptation of Cryptococcus neoformans serotype A strain H99 via the acquisition of different aneuploid chromosomes. These aneuploidies conferred heteroresistance to fluconazole. Importantly, most of the adaptors were cross-tolerant to flucytosine. Some of the aneuploid adaptors were not heteroresistant to fluconazole but were tolerant to amphotericin B. Thus, exposure to one antifungal drug class can promote adaptation to two antifungal drug classes, highlighting the plasticity of the C. neoformans genome and raising concerns about the rapid reduction in the range of treatment options for cryptococcal infections. IMPORTANCE Cryptococcosis is a globally distributed invasive fungal infection caused by infections with Cryptococcus neoformans or Cryptococcus gattii. Only three classes of therapeutic drugs are clinically available for treating cryptococcosis: polyenes (amphotericin B), azoles (fluconazole), and pyrimidine analogues (flucytosine). Fluconazole is the primary drug available in resource-limited countries. Aneuploidy is a genomic state due to the gain or loss of chromosomes. We found that C. neoformans rapidly adapted to fluconazole by acquiring diverse aneuploidies and that specific aneuploidies enabled improved growth of isolates susceptible (tolerance) to amphotericin B and/or cross-tolerance to both fluconazole and flucytosine. Therefore, aneuploidy is an underlying mechanism of drug tolerance that not only arises rapidly during growth in fluconazole but can also confer tolerance to other antifungal drugs without prior exposure to those drugs. Resistant isolates have high MICs, and all cells grow similarly in medium with the drug, while tolerant isolates test as susceptible and grow slowly at drug concentrations above the MIC.
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Hoenigl M, Sprute R, Egger M, Arastehfar A, Cornely OA, Krause R, Lass-Flörl C, Prattes J, Spec A, Thompson GR, Wiederhold N, Jenks JD. The Antifungal Pipeline: Fosmanogepix, Ibrexafungerp, Olorofim, Opelconazole, and Rezafungin. Drugs 2021; 81:1703-1729. [PMID: 34626339 PMCID: PMC8501344 DOI: 10.1007/s40265-021-01611-0] [Citation(s) in RCA: 170] [Impact Index Per Article: 56.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2021] [Indexed: 01/08/2023]
Abstract
The epidemiology of invasive fungal infections is changing, with new populations at risk and the emergence of resistance caused by the selective pressure from increased usage of antifungal agents in prophylaxis, empiric therapy, and agriculture. Limited antifungal therapeutic options are further challenged by drug-drug interactions, toxicity, and constraints in administration routes. Despite the need for more antifungal drug options, no new classes of antifungal drugs have become available over the last 2 decades, and only one single new agent from a known antifungal class has been approved in the last decade. Nevertheless, there is hope on the horizon, with a number of new antifungal classes in late-stage clinical development. In this review, we describe the mechanisms of drug resistance employed by fungi and extensively discuss the most promising drugs in development, including fosmanogepix (a novel Gwt1 enzyme inhibitor), ibrexafungerp (a first-in-class triterpenoid), olorofim (a novel dihyroorotate dehydrogenase enzyme inhibitor), opelconazole (a novel triazole optimized for inhalation), and rezafungin (an echinocandin designed to be dosed once weekly). We focus on the mechanism of action and pharmacokinetics, as well as the spectrum of activity and stages of clinical development. We also highlight the potential future role of these drugs and unmet needs.
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Affiliation(s)
- Martin Hoenigl
- Division of Infectious Diseases, Department of Internal Medicine, Medical University of Graz, Auenbruggerplatz 15, 8036, Graz, Austria.
- Division of Infectious Diseases and Global Public Health, Department of Medicine, University of California San Diego, La Jolla, San Diego, CA, USA.
- Clinical and Translational Fungal-Working Group, University of California San Diego, La Jolla, San Diego, CA, USA.
| | - Rosanne Sprute
- Department I of Internal Medicine, Excellence Center for Medical Mycology (ECMM), University Hospital Cologne, Faculty of Medicine, University of Cologne, Cologne, Germany
- Chair Translational Research, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University Hospital Cologne, Faculty of Medicine, University of Cologne, Cologne, Germany
- German Centre for Infection Research (DZIF), Partner Site Bonn-Cologne, Cologne, Germany
| | - Matthias Egger
- Division of Infectious Diseases, Department of Internal Medicine, Medical University of Graz, Auenbruggerplatz 15, 8036, Graz, Austria
| | - Amir Arastehfar
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, USA
| | - Oliver A Cornely
- Department I of Internal Medicine, Excellence Center for Medical Mycology (ECMM), University Hospital Cologne, Faculty of Medicine, University of Cologne, Cologne, Germany
- Chair Translational Research, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University Hospital Cologne, Faculty of Medicine, University of Cologne, Cologne, Germany
- German Centre for Infection Research (DZIF), Partner Site Bonn-Cologne, Cologne, Germany
- Clinical Trials Centre Cologne (ZKS Köln), University Hospital Cologne, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Robert Krause
- Division of Infectious Diseases, Department of Internal Medicine, Medical University of Graz, Auenbruggerplatz 15, 8036, Graz, Austria
| | - Cornelia Lass-Flörl
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Juergen Prattes
- Division of Infectious Diseases, Department of Internal Medicine, Medical University of Graz, Auenbruggerplatz 15, 8036, Graz, Austria
| | - Andrej Spec
- Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, MI, USA
| | - George R Thompson
- Division of Infectious Diseases, Departments of Internal Medicine and Medical Microbiology and Immunology, University of California Davis Medical Center, Sacramento, CA, USA
| | - Nathan Wiederhold
- Department of Pathology and Laboratory Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Jeffrey D Jenks
- Division of Infectious Diseases and Global Public Health, Department of Medicine, University of California San Diego, La Jolla, San Diego, CA, USA
- Clinical and Translational Fungal-Working Group, University of California San Diego, La Jolla, San Diego, CA, USA
- Division of General Internal Medicine, Department of Medicine, University of California San Diego, La Jolla, San Diego, CA, USA
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Akapo OO, Macnar JM, Kryś JD, Syed PR, Syed K, Gront D. In Silico Structural Modeling and Analysis of Interactions of Tremellomycetes Cytochrome P450 Monooxygenases CYP51s with Substrates and Azoles. Int J Mol Sci 2021; 22:7811. [PMID: 34360577 PMCID: PMC8346148 DOI: 10.3390/ijms22157811] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 05/21/2021] [Accepted: 05/25/2021] [Indexed: 11/16/2022] Open
Abstract
Cytochrome P450 monooxygenase CYP51 (sterol 14α-demethylase) is a well-known target of the azole drug fluconazole for treating cryptococcosis, a life-threatening fungal infection in immune-compromised patients in poor countries. Studies indicate that mutations in CYP51 confer fluconazole resistance on cryptococcal species. Despite the importance of CYP51 in these species, few studies on the structural analysis of CYP51 and its interactions with different azole drugs have been reported. We therefore performed in silico structural analysis of 11 CYP51s from cryptococcal species and other Tremellomycetes. Interactions of 11 CYP51s with nine ligands (three substrates and six azoles) performed by Rosetta docking using 10,000 combinations for each of the CYP51-ligand complex (11 CYP51s × 9 ligands = 99 complexes) and hierarchical agglomerative clustering were used for selecting the complexes. A web application for visualization of CYP51s' interactions with ligands was developed (http://bioshell.pl/azoledocking/). The study results indicated that Tremellomycetes CYP51s have a high preference for itraconazole, corroborating the in vitro effectiveness of itraconazole compared to fluconazole. Amino acids interacting with different ligands were found to be conserved across CYP51s, indicating that the procedure employed in this study is accurate and can be automated for studying P450-ligand interactions to cater for the growing number of P450s.
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Affiliation(s)
- Olufunmilayo Olukemi Akapo
- Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa 3886, South Africa;
| | - Joanna M. Macnar
- College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, Stefana Banacha 2C, 02-097 Warsaw, Poland;
- Biological and Chemical Research Center, Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland;
| | - Justyna D. Kryś
- Biological and Chemical Research Center, Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland;
| | - Puleng Rosinah Syed
- Department of Pharmaceutical Chemistry, College of Health Sciences, University of KwaZulu-Natal, Durban 4000, South Africa;
| | - Khajamohiddin Syed
- Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa 3886, South Africa;
| | - Dominik Gront
- Biological and Chemical Research Center, Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland;
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The Environmental Effects on Virulence Factors and the Antifungal Susceptibility of Cryptococcus neoformans. Int J Mol Sci 2021; 22:ijms22126302. [PMID: 34208294 PMCID: PMC8230809 DOI: 10.3390/ijms22126302] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 06/09/2021] [Accepted: 06/10/2021] [Indexed: 01/10/2023] Open
Abstract
Cryptococcus neoformans is a facultative intracellular pathogen responsible for fungal meningoencephalitis primarily in immunocompromised individuals. It has become evident the pathogenicity of C. neoformans is dependent on the fungal cell’s environment. The differential expression of virulence factors, based on the cell’s environmental conditions, is one mechanism allowing for the environmental control of the pathogenic ability of C. neoformans. Here, we discuss how these virulence factors (including melanin, the polysaccharide capsule, and Antiphagocytic protein 1) have been shown to be differentially expressed dependent on the cell’s environment. The genetics and signaling pathways leading to the environmental-dependent regulation of virulence factors will also be examined. Susceptibility to antifungal therapeutics is also regulated by the environment, and thus affects the pathogenic abilities of C. neoformans and disease outcomes. This review will also examine the role of the C. neoformans’s environment on antifungal susceptibilities, and the genetics and signaling pathways responsible for these susceptibility alterations. By examining the complex interplay between the environment and the pathogenicity of C. neoformans, we have a better understanding of the intricacies of the pathogen–environment interaction and how to exploit this interaction to develop the most effective treatment protocols.
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Abstract
Invasive fungal diseases continue to cause substantial mortality in the enlarging immunocompromised population. It is fortunate that the field has moved past amphotericin B deoxycholate as the only available antifungal drug but despite new classes of antifungal agents both primary and secondary drug resistance in molds and yeasts abound. From the rise of multiple-drug-resistant Candida auris to the agrochemical selection of environmental azole-resistant Aspergillus fumigatus, it is and will be critical to understand antifungal drug resistance and both prevent and treat it with new strategies and agents.
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Sun C, Li F, Wei M, Xiang Z, Chen C, Xu D. Detection and Biological Characteristics of Alternaria alternata Resistant to Difenoconazole from Paris polyphylla var. chinensis, an Indigenous Medicinal Herb. PLANT DISEASE 2021; 105:1546-1554. [PMID: 33349004 DOI: 10.1094/pdis-12-19-2699-re] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Black spot caused by Alternaria alternata (BSAA) is one of the most common diseases of Paris polyphylla var. chinensis, causing yield losses in China. Demethylation inhibitors (DMIs) have been used to control this disease in China for decades. Some farmers have complained about the decreased efficacy of DMIs against BSAA. The objective of this study was to detect and characterize the resistance of A. alternata against difenoconazole from P. polyphylla var. chinensis during 2018. Of the 22 isolates of A. alternata obtained from Sichuan Province in the southwest of China, 20 were resistant to difenoconazole. Mycelial growth rates and sporulation of the difenoconazole-resistant (DfnR) isolates were not different from those of the difenoconazole-sensitive (DfnS) isolates. No cross resistance between difenoconazole and tebuconazole or propiconazole was observed. Mutations were identified at gene AaCYP51 of DfnR isolates based on the sequence alignment of the DfnR and DfnS isolates. All of the mutations could be divided into three resistant genotypes, I (K715R + Y781C), II (K715R + D1140G + T1628A), and III (no mutation). The docking total score of the DfnS isolates was 5.6020, higher than the resistant genotype I (4.4599) or the resistant genotype II (3.8651), suggesting that the DMI resistance of A. alternata may be caused by the decreased affinity between AaCYP51 and difenoconazole.
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Affiliation(s)
- Chunxia Sun
- College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Pesticide, Jiangsu Province, Nanjing 210095 China
| | - Fengjie Li
- College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Pesticide, Jiangsu Province, Nanjing 210095 China
| | - Mengdi Wei
- College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Pesticide, Jiangsu Province, Nanjing 210095 China
| | - Zengxu Xiang
- College of Horticulture, Nanjing Agricultural University, Jiangsu Province, Nanjing 210095 China
| | - Changjun Chen
- College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Pesticide, Jiangsu Province, Nanjing 210095 China
| | - Deliang Xu
- Tea Research Institute of Jiangsu Province, Jiangsu Province, Wuxi 214125 China
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You M, Xu J. What Are the Best Parents for Hybrid Progeny? An Investigation into the Human Pathogenic Fungus Cryptococcus. J Fungi (Basel) 2021; 7:jof7040299. [PMID: 33920829 PMCID: PMC8071107 DOI: 10.3390/jof7040299] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Revised: 04/12/2021] [Accepted: 04/14/2021] [Indexed: 12/13/2022] Open
Abstract
Hybridization between more divergent organisms is likely to generate progeny with more novel genetic interactions and genetic variations. However, the relationship between parental genetic divergence and progeny phenotypic variation remains largely unknown. Here, using strains of the human pathogenic Cryptococcus, we investigated the patterns of such a relationship. Twenty-two strains with up to 15% sequence divergence were mated. Progeny were genotyped at 16 loci. Parental strains and their progeny were phenotyped for growth ability at two temperatures, melanin production at seven conditions, and susceptibility to the antifungal drug fluconazole. We observed three patterns of relationships between parents and progeny for each phenotypic trait, including (i) similar to one of the parents, (ii) intermediate between the parents, and (iii) outside the parental phenotypic range. We found that as genetic distance increases between parental strains, progeny showed increased fluconazole resistance and growth at 37 °C but decreased melanin production under various oxidative and nitrosative stresses. Our findings demonstrate that, depending on the traits, both evolutionarily more similar strains and more divergent strains may be better parents to generate progeny with hybrid vigor. Together, the results indicate the enormous potential of Cryptococcus hybrids in their evolution and adaptation to diverse conditions.
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Nagy G, Kiss S, Varghese R, Bauer K, Szebenyi C, Kocsubé S, Homa M, Bodai L, Zsindely N, Nagy G, Vágvölgyi C, Papp T. Characterization of Three Pleiotropic Drug Resistance Transporter Genes and Their Participation in the Azole Resistance of Mucor circinelloides. Front Cell Infect Microbiol 2021; 11:660347. [PMID: 33937100 PMCID: PMC8079984 DOI: 10.3389/fcimb.2021.660347] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 03/19/2021] [Indexed: 02/04/2023] Open
Abstract
Mucormycosis is a life-threatening opportunistic infection caused by certain members of the fungal order Mucorales. This infection is associated with high mortality rate, which can reach nearly 100% depending on the underlying condition of the patient. Treatment of mucormycosis is challenging because these fungi are intrinsically resistant to most of the routinely used antifungal agents, such as most of the azoles. One possible mechanism of azole resistance is the drug efflux catalyzed by members of the ATP binding cassette (ABC) transporter superfamily. The pleiotropic drug resistance (PDR) transporter subfamily of ABC transporters is the most closely associated to drug resistance. The genome of Mucor circinelloides encodes eight putative PDR-type transporters. In this study, transcription of the eight pdr genes has been analyzed after azole treatment. Only the pdr1 showed increased transcript level in response to all tested azoles. Deletion of this gene caused increased susceptibility to posaconazole, ravuconazole and isavuconazole and altered growth ability of the mutant. In the pdr1 deletion mutant, transcript level of pdr2 and pdr6 significantly increased. Deletion of pdr2 and pdr6 was also done to create single and double knock out mutants for the three genes. After deletion of pdr2 and pdr6, growth ability of the mutant strains decreased, while deletion of pdr2 resulted in increased sensitivity against posaconazole, ravuconazole and isavuconazole. Our result suggests that the regulation of the eight pdr genes is interconnected and pdr1 and pdr2 participates in the resistance of the fungus to posaconazole, ravuconazole and isavuconazole.
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Affiliation(s)
- Gábor Nagy
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
- MTA-SZTE “Lendület” Fungal Pathogenicity Mechanisms Research Group, Department of Microbiology, University of Szeged, Szeged, Hungary
| | - Sándor Kiss
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Rakesh Varghese
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Kitti Bauer
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Csilla Szebenyi
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
- MTA-SZTE “Lendület” Fungal Pathogenicity Mechanisms Research Group, Department of Microbiology, University of Szeged, Szeged, Hungary
| | - Sándor Kocsubé
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Mónika Homa
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
- MTA-SZTE “Lendület” Fungal Pathogenicity Mechanisms Research Group, Department of Microbiology, University of Szeged, Szeged, Hungary
| | - László Bodai
- Department of Biochemistry and Molecular Biology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Nóra Zsindely
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Gábor Nagy
- Department of Biochemistry and Molecular Biology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Csaba Vágvölgyi
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Tamás Papp
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
- MTA-SZTE “Lendület” Fungal Pathogenicity Mechanisms Research Group, Department of Microbiology, University of Szeged, Szeged, Hungary
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The C 2H 2 Transcription Factor SltA Contributes to Azole Resistance by Coregulating the Expression of the Drug Target Erg11A and the Drug Efflux Pump Mdr1 in Aspergillus fumigatus. Antimicrob Agents Chemother 2021; 65:AAC.01839-20. [PMID: 33431412 DOI: 10.1128/aac.01839-20] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 12/29/2020] [Indexed: 02/07/2023] Open
Abstract
The emergence of azole-resistant fungal pathogens has posed a great threat to public health worldwide. Although the molecular mechanism of azole resistance has been extensively investigated, the potential regulators of azole resistance remain largely unexplored. In this study, we identified a new function of the fungal specific C2H2 zinc finger transcription factor SltA (involved in the salt tolerance pathway) in the regulation of azole resistance of the human fungal pathogen Aspergillus fumigatus A lack of SltA results in an itraconazole hypersusceptibility phenotype. Transcriptional profiling combined with LacZ reporter analysis and electrophoretic mobility shift assays (EMSA) demonstrated that SltA is involved in its own transcriptional regulation and also regulates the expression of genes related to ergosterol biosynthesis (erg11A, erg13A, and erg24A) and drug efflux pumps (mdr1, mfsC, and abcE) by directly binding to the conserved 5'-AGGCA-3' motif in their promoter regions, and this binding is dependent on the conserved cysteine and histidine within the C2H2 DNA binding domain of SltA. Moreover, overexpression of erg11A or mdr1 rescues sltA deletion defects under itraconazole conditions, suggesting that erg11A and mdr1 are related to sltA-mediated itraconazole resistance. Most importantly, deletion of SltA in laboratory-derived and clinical azole-resistant isolates significantly attenuates drug resistance. Collectively, we have identified a new function of the transcription factor SltA in regulating azole resistance by coordinately mediating the key azole target Erg11A and the drug efflux pump Mdr1, and targeting SltA may provide a potential strategy for intervention of clinical azole-resistant isolates to improve the efficiency of currently approved antifungal drugs.
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Garcia-Effron G. Molecular Markers of Antifungal Resistance: Potential Uses in Routine Practice and Future Perspectives. J Fungi (Basel) 2021; 7:197. [PMID: 33803304 PMCID: PMC7998127 DOI: 10.3390/jof7030197] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 03/01/2021] [Accepted: 03/04/2021] [Indexed: 12/16/2022] Open
Abstract
Antifungal susceptibility testing (AST) has come to establish itself as a mandatory routine in clinical practice. At the same time, the mycological diagnosis seems to have headed in the direction of non-culture-based methodologies. The downside of these developments is that the strains that cause these infections are not able to be studied for their sensitivity to antifungals. Therefore, at present, the mycological diagnosis is correctly based on laboratory evidence, but the antifungal treatment is undergoing a growing tendency to revert back to being empirical, as it was in the last century. One of the explored options to circumvent these problems is to couple non-cultured based diagnostics with molecular-based detection of intrinsically resistant organisms and the identification of molecular mechanisms of resistance (secondary resistance). The aim of this work is to review the available molecular tools for antifungal resistance detection, their limitations, and their advantages. A comprehensive description of commercially available and in-house methods is included. In addition, gaps in the development of these molecular technologies are discussed.
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Affiliation(s)
- Guillermo Garcia-Effron
- Laboratorio de Micología y Diagnóstico Molecular, Cátedra de Parasitología y Micología, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe CP3000, Argentina; ; Tel.: +54-9342-4575209 (ext. 135)
- Consejo Nacional de Investigaciones Científicas y Tecnológicas, Santa Fe CP3000, Argentina
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Genetic and Phenotypic Characterization of in-Host Developed Azole-Resistant Aspergillus flavus Isolates. J Fungi (Basel) 2021; 7:jof7030164. [PMID: 33668871 PMCID: PMC7996152 DOI: 10.3390/jof7030164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 02/21/2021] [Accepted: 02/22/2021] [Indexed: 11/17/2022] Open
Abstract
Aspergillus flavus is a pathogenic fungal species that can cause pulmonary aspergillosis, and triazole compounds are used for the treatment of these infections. Prolonged exposure to azoles may select for compensatory mutations in the A. flavus genome, resulting in azole resistance. Here, we characterize a series of 11 isogenic A. flavus strains isolated from a patient with pulmonary aspergillosis. Over a period of three months, the initially azole-susceptible strain developed itraconazole and voriconazole resistance. Short tandem repeat analysis and whole-genome sequencing revealed the high genetic relatedness of all isolates, indicating an infection with one single isolate. In contrast, the isolates were macroscopically highly diverse, suggesting an adaptation to the environment due to (epi)genetic changes. The whole-genome sequencing of susceptible and azole-resistant strains showed a number of mutations that might be associated with azole resistance. The majority of resistant strains contain a Y119F mutation in the Cyp51A gene, which corresponds to the Y121F mutation found in A. fumigatus. One azole-resistant strain demonstrated a divergent set of mutations, including a V99A mutation in a major facilitator superfamily (MSF) multidrug transporter (AFLA 083950).
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Characterization of Aspergillus fumigatus cross-resistance between clinical and DMI azole drugs. Appl Environ Microbiol 2021; 87:AEM.02539-20. [PMID: 33355104 PMCID: PMC8090891 DOI: 10.1128/aem.02539-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Drug resistance poses a serious threat to human health and agricultural production. Azole drugs are the largest group of 14-α sterol demethylation inhibitor fungicides that are used both in agriculture and in clinical practice. As plant pathogenic molds share their natural environment with fungi that cause opportunistic infections in humans, both are exposed to a strong and persistent pressure of demethylase inhibitor (DMI) fungicides, including imidazole and triazole drugs. As a result, a loss of efficacy has occurred for this drug class in several species. In the clinical setting, Aspergillus fumigatus azole resistance is a growing public health problem and finding the source of this resistance has gained much attention. It is urgent to determine if there is a direct link between the agricultural use of azole compounds and the different A. fumigatus resistance mechanisms described for clinical triazoles. In this work we have performed A. fumigatus susceptibility testing to clinical triazoles and crop protection DMIs using a collection of azole susceptible and resistant strains which harbor most of the described azole resistance mechanisms. Various DMI susceptibility profiles have been found in the different A. fumigatus populations groups based on their azole resistance mechanism and previous WGS analysis, which suggests that the different resistance mechanisms have different origins and are specifically associated to the local use of a particular DMI.Importance Due to the worldwide emergence of A. fumigatus azole resistance, this opportunistic pathogen poses a serious health threat and, therefore, it has been included in the Watch List of the CDC 2019 Antimicrobial Resistance Threats Report. Azoles play a critical role in the control and management of fungal diseases, not only in the clinical setting but also in agriculture. Thus, azole resistance leads to a limited therapeutic arsenal which reduces the treatment options for aspergillosis patients, increasing their mortality risk. Evidence is needed to understand whether A. fumigatus azole resistance is emerging from an agricultural source due to the extended use of demethylase inhibitors as fungicides, or whether it is coming from somewhere else such as the clinical setting. If the environmental route is demonstrated, the current use and management of azole antifungal compounds might be forced to change in the forthcoming years.
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Advances in Fusarium drug resistance research. J Glob Antimicrob Resist 2021; 24:215-219. [PMID: 33460843 DOI: 10.1016/j.jgar.2020.12.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 11/19/2020] [Accepted: 12/16/2020] [Indexed: 12/12/2022] Open
Abstract
Fusarium species cause many diseases in plants and humans, which results in a great number of economic losses every year. The management of plant diseases and related human diseases caused by Fusarium is challenging as many kinds of Fusarium may be intrinsically resistant to antifungal drugs, not to mention the fact that they can acquire drug resistance, which is common in clinical practice. To date, the drug resistance of Fusarium is mainly related to target alterations, drug efflux and biofilm formation. This article reviews recent studies related to the mechanism of Fusarium resistance, and summarizes the key molecules affecting resistance.
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Rosam K, Monk BC, Lackner M. Sterol 14α-Demethylase Ligand-Binding Pocket-Mediated Acquired and Intrinsic Azole Resistance in Fungal Pathogens. J Fungi (Basel) 2020; 7:jof7010001. [PMID: 33374996 PMCID: PMC7822023 DOI: 10.3390/jof7010001] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 12/17/2020] [Accepted: 12/18/2020] [Indexed: 12/17/2022] Open
Abstract
The fungal cytochrome P450 enzyme sterol 14α-demethylase (SDM) is a key enzyme in the ergosterol biosynthesis pathway. The binding of azoles to the active site of SDM results in a depletion of ergosterol, the accumulation of toxic intermediates and growth inhibition. The prevalence of azole-resistant strains and fungi is increasing in both agriculture and medicine. This can lead to major yield loss during food production and therapeutic failure in medical settings. Diverse mechanisms are responsible for azole resistance. They include amino acid (AA) substitutions in SDM and overexpression of SDM and/or efflux pumps. This review considers AA affecting the ligand-binding pocket of SDMs with a primary focus on substitutions that affect interactions between the active site and the substrate and inhibitory ligands. Some of these interactions are particularly important for the binding of short-tailed azoles (e.g., voriconazole). We highlight the occurrence throughout the fungal kingdom of some key AA substitutions. Elucidation of the role of these AAs and their substitutions may assist drug design in overcoming some common forms of innate and acquired azole resistance.
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Affiliation(s)
- Katharina Rosam
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Schöpfstrasse 41, 6020 Innsbruck, Austria;
| | - Brian C. Monk
- Sir John Walsh Research Institute and Department of Oral Biology, Faculty of Dentistry, University of Otago, PO Box 56, 9054 Dunedin, New Zealand;
| | - Michaela Lackner
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Schöpfstrasse 41, 6020 Innsbruck, Austria;
- Correspondence: ; Tel.: +43-512-003-70725
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Gonzalez-Jimenez I, Lucio J, Amich J, Cuesta I, Sanchez Arroyo R, Alcazar-Fuoli L, Mellado E. A Cyp51B Mutation Contributes to Azole Resistance in Aspergillus fumigatus. J Fungi (Basel) 2020; 6:jof6040315. [PMID: 33255951 PMCID: PMC7712412 DOI: 10.3390/jof6040315] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 11/20/2020] [Accepted: 11/23/2020] [Indexed: 12/14/2022] Open
Abstract
The emergence and spread of Aspergillus fumigatus azole resistance has been acknowledged worldwide. The main problem of azole resistance is the limited therapeutic options for patients suffering aspergillosis. Azole resistance mechanisms have been mostly linked to the enzyme Cyp51A, a target of azole drugs, with a wide variety of modifications responsible for the different resistance mechanisms described to date. However, there are increasing reports of A. fumigatus strains showing azole resistance without Cyp51A modifications, and thus, novel resistance mechanisms are being explored. Here, we characterized two isogenic A. fumigatus clinical strains isolated two years apart from the same patient. Both strains were resistant to clinical azoles but showed different azole resistance mechanisms. One strain (CM8940) harbored a previously described G54A mutation in Cyp51A while the other strain (CM9640) had a novel G457S mutation in Cyp51B, the other target of azoles. In addition, this second strain had a F390L mutation in Hmg1. CM9640 showed higher levels of gene expression of cyp51A, cyp51B and hmg1 than the CM8940 strain. The role of the novel mutation found in Cyp51B together with the contribution of a mutation in Hmg1 in azole resistance is discussed.
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Affiliation(s)
- Irene Gonzalez-Jimenez
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III (ISCIII), Majadahonda, 28222 Madrid, Spain; (I.G.-J.); (J.L.); (L.A.-F.)
| | - Jose Lucio
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III (ISCIII), Majadahonda, 28222 Madrid, Spain; (I.G.-J.); (J.L.); (L.A.-F.)
| | - Jorge Amich
- Manchester Fungal Infection Group (MFIG), Division of Infection, Immunity and Respiratory Medicine, University of Manchester, Manchester M13 9PL, UK;
| | - Isabel Cuesta
- Bioinformatics Unit, Common Scientific Technical Units, Instituto de Salud Carlos III (ISCIII), Majadahonda, 28222 Madrid, Spain;
| | | | - Laura Alcazar-Fuoli
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III (ISCIII), Majadahonda, 28222 Madrid, Spain; (I.G.-J.); (J.L.); (L.A.-F.)
- Spanish Network for Research in Infectious Diseases (REIPI RD16/CIII/0004/0003), Instituto de Salud Carlos III (ISCIII), Majadahonda, 28222 Madrid, Spain
| | - Emilia Mellado
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III (ISCIII), Majadahonda, 28222 Madrid, Spain; (I.G.-J.); (J.L.); (L.A.-F.)
- Spanish Network for Research in Infectious Diseases (REIPI RD16/CIII/0004/0003), Instituto de Salud Carlos III (ISCIII), Majadahonda, 28222 Madrid, Spain
- Correspondence:
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Stanford FA, Voigt K. Iron Assimilation during Emerging Infections Caused by Opportunistic Fungi with emphasis on Mucorales and the Development of Antifungal Resistance. Genes (Basel) 2020; 11:genes11111296. [PMID: 33143139 PMCID: PMC7693903 DOI: 10.3390/genes11111296] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 10/23/2020] [Accepted: 10/28/2020] [Indexed: 02/06/2023] Open
Abstract
Iron is a key transition metal required by most microorganisms and is prominently utilised in the transfer of electrons during metabolic reactions. The acquisition of iron is essential and becomes a crucial pathogenic event for opportunistic fungi. Iron is not readily available in the natural environment as it exists in its insoluble ferric form, i.e., in oxides and hydroxides. During infection, the host iron is bound to proteins such as transferrin, ferritin, and haemoglobin. As such, access to iron is one of the major hurdles that fungal pathogens must overcome in an immunocompromised host. Thus, these opportunistic fungi utilise three major iron acquisition systems to overcome this limiting factor for growth and proliferation. To date, numerous iron acquisition pathways have been fully characterised, with key components of these systems having major roles in virulence. Most recently, proteins involved in these pathways have been linked to the development of antifungal resistance. Here, we provide a detailed review of our current knowledge of iron acquisition in opportunistic fungi, and the role iron may have on the development of resistance to antifungals with emphasis on species of the fungal basal lineage order Mucorales, the causative agents of mucormycosis.
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Affiliation(s)
- Felicia Adelina Stanford
- Jena Microbial Resource Collection, Leibniz Institute for Natural Product Research, and Infection Biology–Hans Knöll Institute, Jena, Adolf-Reichwein-Straße 23, 07745 Jena, Germany;
- Institute of Microbiology, Faculty of Biological Sciences, Friedrich-Schiller University Jena, Neugasse 25, 07743 Jena, Germany
| | - Kerstin Voigt
- Jena Microbial Resource Collection, Leibniz Institute for Natural Product Research, and Infection Biology–Hans Knöll Institute, Jena, Adolf-Reichwein-Straße 23, 07745 Jena, Germany;
- Institute of Microbiology, Faculty of Biological Sciences, Friedrich-Schiller University Jena, Neugasse 25, 07743 Jena, Germany
- Leibniz Institute for Natural Product Research and Infection Biology–Hans Knöll Institute, Jena Microbial Resource Collection Adolf-Reichwein-Straße 23, 07745 Jena, Germany
- Correspondence: ; Tel.: +49-3641-532-1395; Fax: +49-3641-532-2395
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Bermas A, Geddes‐McAlister J. Combatting the evolution of antifungal resistance in
Cryptococcus neoformans. Mol Microbiol 2020; 114:721-734. [DOI: 10.1111/mmi.14565] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 06/09/2020] [Accepted: 06/22/2020] [Indexed: 02/06/2023]
Affiliation(s)
- Arianne Bermas
- Department of Molecular and Cellular Biology University of Guelph Guelph ON Canada
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Zhang C, Imran M, Liu M, Li Z, Gao H, Duan H, Zhou S, Liu X. Two Point Mutations on CYP51 Combined With Induced Expression of the Target Gene Appeared to Mediate Pyrisoxazole Resistance in Botrytis cinerea. Front Microbiol 2020; 11:1396. [PMID: 32714305 PMCID: PMC7340008 DOI: 10.3389/fmicb.2020.01396] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Accepted: 05/29/2020] [Indexed: 11/24/2022] Open
Abstract
Botrytis cinerea is a destructive plant pathogenic ascomycete that causes serious pre- and post-harvest losses worldwide. The novel sterol 14α-demethylase inhibitor (DMI) pyrisoxazole was recently registered for the control of tomato gray mold caused by B. cinerea in China. Baseline sensitivity of 110 B. cinerea isolates collected from nine provinces in China to pyrisoxazole was demonstrated, with a mean EC50 of 0.057 ± 0.029 μg/ml. Eleven stable mutants resistant to pyrisoxazole were generated via UV irradiation (RU-mutants) and spontaneous selection (RS-mutants) of conidia. The efficacy of pyrisoxazole against the resistant mutants was significantly lower than that of the sensitive isolates. Most of the pyrisoxazole- resistant mutants were less fit than the sensitive isolates, with reduced sporulation, conidia germination, sclerotium production, and pathogenicity, which was confirmed by the competitive ability test. Positive cross-resistance was only observed between pyrisoxazole and the DMIs tebuconazole and prochloraz, but not between pyrisoxazole and non-DMIs iprodione, procymidone, diethofencarb, fluazinam, pyrimethanil, or fludioxonil. A two-point mutation, at G476S and K104E in the RU-mutants, and a one point mutation, M231T, in the RS-mutants, were detected in the CYP51 protein of the resistant mutants. When exposed to pyrisoxazole, the induced expression level of CYP51 increased in the resistant isolates as compared to sensitive ones. Molecular docking suggested that G476S and M231T mutations both led to the loss of electrostatic interactions between CYP51 and pyrisoxazole, while no change was found with the K104E mutation. Thus, two point mutations on CYP51 protein combined with induced expression of its target gene appeared to mediate the pyrisoxazole resistance of B cinerea.
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Affiliation(s)
- Can Zhang
- China Agricultural University, Beijing, China
| | | | - Min Liu
- China Agricultural University, Beijing, China
| | - Zhiwen Li
- Institute for the Control of Agrochemicals of Shaanxi Province, Xi'an, China
| | - Huige Gao
- China Agricultural University, Beijing, China
| | | | - Shunli Zhou
- China Agricultural University, Beijing, China
| | - Xili Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, China
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42
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Bertout S, Roger F, Drakulovski P, Martin A, Gouveia T, Kassi F, Menan H, Krasteva D, Delaporte E, Bellet V. African ST173 Cryptococcus deuterogattii strains are commonly less susceptible to fluconazole: An unclear mechanism of resistance. J Glob Antimicrob Resist 2020; 21:262-269. [DOI: 10.1016/j.jgar.2019.10.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 09/20/2019] [Accepted: 10/17/2019] [Indexed: 12/29/2022] Open
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Ghaffar M, Orr C, Webb G. Antiphagocytic protein 1 increases the susceptibility of Cryptococcus neoformans to amphotericin B and fluconazole. PLoS One 2019; 14:e0225701. [PMID: 31800598 PMCID: PMC6892493 DOI: 10.1371/journal.pone.0225701] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 11/11/2019] [Indexed: 02/07/2023] Open
Abstract
Cryptococcus neoformans is a facultative intracellular pathogen responsible for the most common cause of fungal meningioencephalitis, occurring primarily in immunocompromised individuals. Antiphagocytic protein 1 (App1) is a virulence factor produced by C. neoformans that inhibits phagocytosis of the yeast by host macrophages. Treatment of cryptococcosis includes amphotericin B, fluconazole, and flucytosine. Virulence factors have been shown to affect the susceptibility of the pathogen to antifungal drugs. In this study, we aimed to examine the relationship between App1 and antifungal drugs. We found that short-term exposure to amphotericin B downregulates APP1 expression while exposure to fluconazole upregulates APP1. In addition, App1 was found to increase the susceptibility of the yeast to amphotericin B and fluconazole. This study provides evidence of an intricate relationship between App1 and antifungal drugs.
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Affiliation(s)
- Muhammad Ghaffar
- Division of Natural Sciences and Engineering, University of South Carolina Upstate, Spartanburg, South Carolina, United States of America
| | - Cody Orr
- Division of Natural Sciences and Engineering, University of South Carolina Upstate, Spartanburg, South Carolina, United States of America
| | - Ginny Webb
- Division of Natural Sciences and Engineering, University of South Carolina Upstate, Spartanburg, South Carolina, United States of America
- * E-mail:
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Zafar H, Altamirano S, Ballou ER, Nielsen K. A titanic drug resistance threat in Cryptococcus neoformans. Curr Opin Microbiol 2019; 52:158-164. [PMID: 31765991 DOI: 10.1016/j.mib.2019.11.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 10/01/2019] [Accepted: 11/01/2019] [Indexed: 10/25/2022]
Abstract
Increasing resistance to frontline antifungals is a growing threat to global health. In the face of high rates of relapse for patients with cryptococcal meningitis and frequent drug resistance in clinical isolates, recent insights into Cryptococcus neoformans morphogenesis and genome plasticity take on new and urgent meaning. Here we review the state of the understanding of mechanisms of drug resistance in the context of host-relevant changes in Cryptococcus morphology and cell ploidy.
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Affiliation(s)
- Hanna Zafar
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Sophie Altamirano
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, 55455 USA
| | - Elizabeth R Ballou
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
| | - Kirsten Nielsen
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, 55455 USA.
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Selb R, Fuchs V, Graf B, Hamprecht A, Hogardt M, Sedlacek L, Schwarz R, Idelevich EA, Becker SL, Held J, Küpper-Tetzel CP, McCormick-Smith I, Heckmann D, Gerkrath J, Han CO, Wilmes D, Rickerts V. Molecular typing and in vitro resistance of Cryptococcus neoformans clinical isolates obtained in Germany between 2011 and 2017. Int J Med Microbiol 2019; 309:151336. [PMID: 31444102 DOI: 10.1016/j.ijmm.2019.151336] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 07/05/2019] [Accepted: 07/31/2019] [Indexed: 02/07/2023] Open
Abstract
Cryptococcosis is a fungal infection of the central nervous system predominantly caused by Cryptococcus neoformans in immunocompromised patients. In several countries worldwide, up to 50% of isolates show in vitro resistance to clinically used antifungals including fluconazole. No prospective data on susceptibility to antifungal drugs are available for Germany. In this study, we characterised all C. neoformans isolates collected from individual patients' samples at the German reference laboratory for cryptococcosis 2011 and 2017 (n = 133) by multi-locus sequence typing and phenotypic drug susceptibility testing. We identified serotype A/genotype VNI isolates belonging to clonal complexes previously described from Europe, Africa, Asia and South America as the most prevalent agents of cryptococcosis in Germany. Overall, we observed minimal inhibitory concentrations (MICs) above the epidemiological cut-offs (ECVs) in 1.6% of isolates regarding fluconazole and 2.3% of isolates regarding 5-flucytosine. Here, two C. neoformans var. grubii isolates displayed decreased drug susceptibility to fluconazole, one of them additionally to 5-flucytosine. We also found 5-flucytosine MICs above the ECV for two C. neoformans var. neoformans isolates. We identified a novel mutation in the ERG11 gene which might be associated with the elevated fluconazole MIC in one of the isolates. The clinical importance of the detected in vitro resistance is documented by patient histories showing relapsed infection or primary fatal disease. Of note, sertraline demonstrated antifungal activity comparable to previous reports. Systematic collection of susceptibility data in combination with molecular typing of C. neoformans is important to comprehensively assess the spread of isolates and to understand their drug resistance patterns.
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Affiliation(s)
- Regina Selb
- European Public Health Microbiology Programme (EUPHEM), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden; Department of Infectious Diseases, Unit for Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany
| | - Vidmante Fuchs
- Department of Infectious Diseases, Unit for Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany
| | - Barbara Graf
- Labor Berlin - Charité Vivantes GmbH, Berlin, Germany
| | - Axel Hamprecht
- Institute for Medical Microbiology, Immunology and Hygiene, University Hospital of Cologne, Cologne, Germany
| | - Michael Hogardt
- Institute of Medical Microbiology and Infection Control, Goethe University Hospital, Frankfurt/Main, Germany
| | - Ludwig Sedlacek
- Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
| | - Roman Schwarz
- MVZ Dr. Stein and colleagues, Moenchengladbach, Germany
| | - Evgeny A Idelevich
- Institute of Medical Microbiology, University Hospital Muenster, Muenster, Germany
| | - Sören L Becker
- Institute of Medical Microbiology and Hygiene, Saarland University, Homburg, Germany
| | - Jürgen Held
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany
| | - Claus P Küpper-Tetzel
- Medical Department II, Infectious Diseases Unit, Goethe-University Hospital Frankfurt, Frankfurt, Germany
| | - Ilka McCormick-Smith
- Department of Infectious Diseases, Unit for Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany
| | - Daniela Heckmann
- Department of Infectious Diseases, Unit for Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany
| | - Jasmin Gerkrath
- Department of Infectious Diseases, Unit for Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany
| | - Chang-Ok Han
- Department of Infectious Diseases, Unit for Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany
| | - Dunja Wilmes
- Department of Infectious Diseases, Unit for Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany
| | - Volker Rickerts
- Department of Infectious Diseases, Unit for Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany.
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Distribution and Diversity of Cytochrome P450 Monooxygenases in the Fungal Class Tremellomycetes. Int J Mol Sci 2019; 20:ijms20122889. [PMID: 31200551 PMCID: PMC6627453 DOI: 10.3390/ijms20122889] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Revised: 05/25/2019] [Accepted: 05/30/2019] [Indexed: 12/16/2022] Open
Abstract
Tremellomycetes, a fungal class in the subphylum Agaricomycotina, contain well-known opportunistic and emerging human pathogens. The azole drug fluconazole, used in the treatment of diseases caused by some species of Tremellomycetes, inhibits cytochrome P450 monooxygenase CYP51, an enzyme that converts lanosterol into an essential component of the fungal cell membrane ergosterol. Studies indicate that mutations and over-expression of CYP51 in species of Tremellomycetes are one of the reasons for fluconazole resistance. Moreover, the novel drug, VT-1129, that is in the pipeline is reported to exert its effect by binding and inhibiting CYP51. Despite the importance of CYPs, the CYP repertoire in species of Tremellomycetes has not been reported to date. This study intends to address this research gap. Comprehensive genome-wide CYP analysis revealed the presence of 203 CYPs (excluding 16 pseudo-CYPs) in 23 species of Tremellomycetes that can be grouped into 38 CYP families and 72 CYP subfamilies. Twenty-three CYP families are new and three CYP families (CYP5139, CYP51 and CYP61) were conserved across 23 species of Tremellomycetes. Pathogenic cryptococcal species have 50% fewer CYP genes than non-pathogenic species. The results of this study will serve as reference for future annotation and characterization of CYPs in species of Tremellomycetes.
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Zhang J, Li L, Lv Q, Yan L, Wang Y, Jiang Y. The Fungal CYP51s: Their Functions, Structures, Related Drug Resistance, and Inhibitors. Front Microbiol 2019; 10:691. [PMID: 31068906 PMCID: PMC6491756 DOI: 10.3389/fmicb.2019.00691] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Accepted: 03/19/2019] [Indexed: 12/18/2022] Open
Abstract
CYP51 (Erg11) belongs to the cytochrome P450 monooxygenase (CYP) superfamily and mediates a crucial step of the synthesis of ergosterol, which is a fungal-specific sterol. It is also the target of azole drugs in clinical practice. In recent years, researches on fungal CYP51 have stepped into a new stage attributing to the discovery of crystal structures of the homologs in Candida albicans, Cryptococcus neoformans and Aspergillus fumigatus. This review summarizes the functions, structures of fungal CYP51 proteins, and the inhibitors targeting these homologs. In particular, several drug-resistant mechanisms associated with the fungal CYP51s are introduced. The sequences and crystal structures of CYP51 proteins in different fungal species are also compared. These will provide new insights for the advancement of research on antifungal agents.
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Affiliation(s)
- Jingxiang Zhang
- Center for New Drug Research, School of Pharmacy, Second Military Medical University, Shanghai, China
| | - Liping Li
- Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, China
- Department of Pharmacology, Tongji University School of Medicine, Shanghai, China
| | - Quanzhen Lv
- Center for New Drug Research, School of Pharmacy, Second Military Medical University, Shanghai, China
| | - Lan Yan
- Center for New Drug Research, School of Pharmacy, Second Military Medical University, Shanghai, China
- *Correspondence: Lan Yan, Yan Wang, Yuanying Jiang,
| | - Yan Wang
- Center for New Drug Research, School of Pharmacy, Second Military Medical University, Shanghai, China
- *Correspondence: Lan Yan, Yan Wang, Yuanying Jiang,
| | - Yuanying Jiang
- Center for New Drug Research, School of Pharmacy, Second Military Medical University, Shanghai, China
- Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, China
- Department of Pharmacology, Tongji University School of Medicine, Shanghai, China
- *Correspondence: Lan Yan, Yan Wang, Yuanying Jiang,
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48
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Molecular Confirmation of the Linkage between the Rhizopus oryzae CYP51A Gene Coding Region and Its Intrinsic Voriconazole and Fluconazole Resistance. Antimicrob Agents Chemother 2018; 62:AAC.00224-18. [PMID: 29891608 DOI: 10.1128/aac.00224-18] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 05/11/2018] [Indexed: 12/13/2022] Open
Abstract
Rhizopus oryzae is the most prevalent causative agent of mucormycosis, an increasingly reported opportunistic fungal infection. These Mucorales are intrinsically resistant to Candida- and Aspergillus-active antifungal azole drugs, such as fluconazole (FLC) and voriconazole, respectively. Despite its importance, the molecular mechanisms of its intrinsic azole resistance have not been elucidated yet. The aim of this work was to establish if the Rhizopus oryzaeCYP51 genes are uniquely responsible for intrinsic voriconazole and fluconazole resistance in these fungal pathogens. Two CYP51 genes were identified in the R. oryzae genome. We classified them as CYP51A and CYP51B based on their sequence similarity with other known fungal CYP51 genes. Later, we obtained a chimeric Aspergillus fumigatus strain harboring a functional R. oryzae CYP51A gene expressed under the regulation of the wild-type A. fumigatusCYP51A promoter and terminator. The mutant was selected after transformation by using a novel procedure taking advantage of the FLC hypersusceptibility of the A. fumigatusCYP51A deletion mutant used as the recipient strain. The azole susceptibility patterns of the A. fumigatus transformants harboring R. oryzae CYP51A mimicked exactly the azole susceptibility patterns of this mucormycete. The data presented in this work demonstrate that the R. oryzae CYP51A coding sequence is uniquely responsible for the R. oryzae azole susceptibility patterns.
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McColl AI, Bleackley MR, Anderson MA, Lowe RGT. Resistance to the Plant Defensin NaD1 Features Modifications to the Cell Wall and Osmo-Regulation Pathways of Yeast. Front Microbiol 2018; 9:1648. [PMID: 30087664 PMCID: PMC6066574 DOI: 10.3389/fmicb.2018.01648] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 07/02/2018] [Indexed: 11/24/2022] Open
Abstract
Over the last few decades, the emergence of resistance to commonly used antifungal molecules has become a major barrier to effective treatment of recurrent life-threatening fungal diseases. Resistance combined with the increased incidence of fungal diseases has created the need for new antifungals, such as the plant defensin NaD1, with different mechanisms of action to broaden treatment options. Antimicrobial peptides produced in plants and animals are promising new molecules in the arsenal of antifungal agents because they have different mechanisms of action to current antifungals and are often targeted specifically to fungal pathogens (van der Weerden et al., 2013). A key step in the development of novel antifungals is an understanding of the potential for the fungus to develop resistance. Here, we have used the prototypic plant defensin NaD1 in serial passages with the model fungus Saccharomyces cerevisiae to examine the evolution of resistance to plant antifungal peptides. The yeast strains did develop tolerance to NaD1, but it occurred more slowly than to the clinically used antifungal caspofungin. Sequencing the genomes of the strains with increased tolerance failed to identify any ‘hotspot’ mutations associated with increased tolerance to NaD1 and led to the identification of 12 genes that are involved in resistance. Characterization of the strains with increased tolerance to NaD1 also revealed changes in tolerance to abiotic stressors. Resistance developed slowly via an accumulation of single nucleotide mutations and had a fitness penalty associated with it. One of the genes identified FPS1, revealed that there is a common mechanism of resistance to NaD1 that involves the osmotic stress response pathway. These data indicate that it is more difficult to generate resistance to antimicrobial peptides such as NaD1 compared to small molecule antifungals.
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Affiliation(s)
- Amanda I McColl
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Mark R Bleackley
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Marilyn A Anderson
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Rohan G T Lowe
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
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Ishita K, Stefanopoulos S, Khalil A, Cheng X, Tjarks W, Rappleye CA. Synthesis and biological evaluation of aminothiazoles against Histoplasma capsulatum and Cryptococcus neoformans. Bioorg Med Chem 2018; 26:2251-2261. [PMID: 29580849 PMCID: PMC5935597 DOI: 10.1016/j.bmc.2018.01.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 01/15/2018] [Accepted: 01/26/2018] [Indexed: 01/13/2023]
Abstract
The design and synthesis of a library of forty novel 2-aminoazole analogues as well as their evaluation as antifungal compounds against Histoplasma capsulatum and Cryptococcus neoformans is described. These structures were derived from N-[5-(1-naphthalenylmethyl)-2-thiazolyl]cyclohexanecarboxamide (41F5), a fungistatic agent previously identified through phenotypic screening (Antimicrob Agents Chemother. 2013;57:4349). Modifications to improve potency and water-solubility of 41F5 focused primarily on the 5-naphthalenyl group, the thiazole core, and the methylene linker between these two structural elements. In general, compounds with lipophilic [5+6] bicyclic ring systems, such as the 7-benzothiophenyl- and 4-indanyl groups, at the 5-position were 2-3 times more active against both fungal species as compared to 41F5. Also, introduction of a carbonyl group at the methylene linker of 41F5 resulted in a 2-3-fold increase in potency. These highly active compounds also showed generally low toxicities against murine P388D1 macrophages resulting in selectivity indices ranging from 63 to >200. Compounds that were highly active against fluconazole-sensitive C. neoformans strains had almost identical activity against fluconazole-resistant variants of this fungus indicating that 14α-demethylase is not their molecular target. Highly active compounds also retained activity against H. capsulatum phagocytosed into P388D1 macrophages.
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Affiliation(s)
- Keisuke Ishita
- Division of Medicinal Chemistry & Pharmacognosy, The Ohio State University, Columbus, OH 43210, United States
| | | | - Ahmed Khalil
- Division of Medicinal Chemistry & Pharmacognosy, The Ohio State University, Columbus, OH 43210, United States
| | - Xiaolin Cheng
- Division of Medicinal Chemistry & Pharmacognosy, The Ohio State University, Columbus, OH 43210, United States
| | - Werner Tjarks
- Division of Medicinal Chemistry & Pharmacognosy, The Ohio State University, Columbus, OH 43210, United States
| | - Chad A Rappleye
- Department of Microbiology, The Ohio State University, Columbus, OH, United States; Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, United States.
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