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Day AW, Kumamoto CA. Selection of ethanol tolerant strains of Candida albicans by repeated ethanol exposure results in strains with reduced susceptibility to fluconazole. PLoS One 2024; 19:e0298724. [PMID: 38377103 PMCID: PMC10878505 DOI: 10.1371/journal.pone.0298724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 01/23/2024] [Indexed: 02/22/2024] Open
Abstract
Candida albicans is a commensal yeast that has important impacts on host metabolism and immune function, and can establish life-threatening infections in immunocompromised individuals. Previously, C. albicans colonization has been shown to contribute to the progression and severity of alcoholic liver disease. However, relatively little is known about how C. albicans responds to changing environmental conditions in the GI tract of individuals with alcohol use disorder, namely repeated exposure to ethanol. In this study, we repeatedly exposed C. albicans to high concentrations (10% vol/vol) of ethanol-a concentration that can be observed in the upper GI tract of humans following consumption of alcohol. Following this repeated exposure protocol, ethanol small colony (Esc) variants of C. albicans isolated from these populations exhibited increased ethanol tolerance, altered transcriptional responses to ethanol, and cross-resistance/tolerance to the frontline antifungal fluconazole. These Esc strains exhibited chromosomal copy number variations and carried polymorphisms in genes previously associated with the acquisition of fluconazole resistance during human infection. This study identifies a selective pressure that can result in evolution of fluconazole tolerance and resistance without previous exposure to the drug.
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Affiliation(s)
- Andrew W. Day
- Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, United States of America
- Department of Molecular Biology and Microbiology, Tufts University, Boston, Massachusetts, United States of America
| | - Carol A. Kumamoto
- Department of Molecular Biology and Microbiology, Tufts University, Boston, Massachusetts, United States of America
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Wu Z, Bi Y, Zhang J, Gao T, Li X, Hao J, Li G, Liu P, Liu X. Multidrug resistance of Botrytis cinerea associated with its adaptation to plant secondary metabolites. mBio 2024; 15:e0223723. [PMID: 38259067 PMCID: PMC10865845 DOI: 10.1128/mbio.02237-23] [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: 08/20/2023] [Accepted: 12/12/2023] [Indexed: 01/24/2024] Open
Abstract
Fungicides are an effective way to control gray mold of grapes, but the pathogen Botrytis cinerea can develop resistance, overcoming the effectiveness of a fungicide that is repeatedly applied. More importantly, the emergence of multidrug resistance (MDR) in the field, where multiple fungicides with different modes of action simultaneously lose their efficacies, is a significant concern. MDR is associated with ATP-binding cassette (ABC) transporters of the pathogen, and certain plant secondary metabolites (PSMs) stimulate the upregulation of ABC transporters, we hypothesized that the pathogen's preadaptation to PSMs might contribute to MDR development. To test this in B. cinerea, ten PSMs, namely, resveratrol, reserpine, chalcone, flavanone, eugenol, farnesol, anethene, camptothecin, salicylic acid, and psoralen, were selected based on their association with ABC transporters involved in fungicide resistance. B. cinerea strain B05.10 was continuously transferred for 15 generations on potato dextrose agar amended with a PSM (PDAP), and sensitivities to PSMs and fungicides were examined on the 5th, 10th, and 15th generations. RNA was extracted from B. cinerea from the selected generations. After 15 generations of culture transfers, an up-regulation was observed in the expression of ABC transporter-encoding genes BcatrB, BcatrD, and BcatrK using quantitative polymerase chain reaction (qPCR). This upregulation was found to contribute to MDR of B. cinerea against two or more fungicides, among azoxystrobin, boscalid, fludioxonil, difenoconazole, prochloraz, and pyrimethanil. This finding was confirmed through genetic transformation. The decreased sensitivity of B. cinerea to fungicides was confirmed as a subsequent MDR phenotype after exposure to camptothecin, flavanone, and resveratrol. Besides, transcriptome analysis also revealed the upregulation of transcription factors related to ABC expression following resveratrol exposure. This suggests that PSMs contributed to inducing preadaptation of B. cinerea, leading to subsequent MDR.IMPORTANCEThe emergence of MDR in plant pathogens is a threat to plant disease management and leads to the use of excessive fungicides. Botrytis cinerea is of particular concern because its MDR has widely emerged in the field. Understanding its genesis is the first step for controlling MDR. In this study, the contribution of PSMs to MDR has been examined. Effective management of this pathogen in agroecosystems relies on a better understanding of how it copes with phytochemicals or fungicides.
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Affiliation(s)
- Zhaochen Wu
- Department of Plant Pathology, China Agricultural University, Beijing, China
| | - Yue Bi
- Department of Plant Pathology, China Agricultural University, Beijing, China
- Department of Plant Pathology, Tianjin Agricultural University, Tianjin, China
| | - Junting Zhang
- Department of Plant Pathology, China Agricultural University, Beijing, China
| | - Tuqiang Gao
- Department of Plant Pathology, China Agricultural University, Beijing, China
| | - Xueming Li
- Department of Plant Pathology, China Agricultural University, Beijing, China
| | - Jianjun Hao
- School of Food and Agriculture, University of Maine, Orono, Maine, USA
| | - Guihua Li
- College of Plant Sciences, Jilin University, Changchun, China
| | - Pengfei Liu
- Department of Plant Pathology, China Agricultural University, Beijing, China
| | - Xili Liu
- Department of Plant Pathology, China Agricultural University, Beijing, China
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Hu T, Wang S, Bing J, Zheng Q, Du H, Li C, Guan Z, Bai FY, Nobile CJ, Chu H, Huang G. Hotspot mutations and genomic expansion of ERG11 are major mechanisms of azole resistance in environmental and human commensal isolates of Candida tropicalis. Int J Antimicrob Agents 2023; 62:107010. [PMID: 37863341 DOI: 10.1016/j.ijantimicag.2023.107010] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Revised: 10/11/2023] [Accepted: 10/14/2023] [Indexed: 10/22/2023]
Abstract
OBJECTIVES Infections caused by azole-resistant Candida tropicalis strains are increasing in clinical settings. The reason for this epidemical change and the mechanisms of C. tropicalis azole resistance are not fully understood. METHODS In this study, we performed biological and genomic analyses of 239 C. tropicalis strains, including 115 environmental and 124 human commensal isolates. RESULTS Most (99.2%) of the isolates had a baseline diploid genome. The strains from both environmental and human niches exhibit similar abilities to survive under stressful conditions and produce secreted aspartic proteases. However, the human commensal isolates exhibited a stronger ability to filament than the environmental strains. We found that 19 environmental isolates (16.5%) and 24 human commensal isolates (19.4%) were resistant to fluconazole. Of the fluconazole-resistant strains, 37 isolates (86.0%) also exhibited cross-resistance to voriconazole. Whole-genome sequencing and phylogenetic analyses revealed that both environmental and commensal isolates were widely distributed in a number of genetic clusters, but the two populations exhibited a close genetic association. The majority of fluconazole-resistant isolates were clustered within a single clade (X). CONCLUSIONS The combination of hotspot mutations (Y132F and S154F) and genomic expansion of ERG11, which encodes the azole target lanosterol 14-α-demethylase and represents a major target of azole drugs, was a major mechanism for the development of azole resistance. The isolates carrying both hotspot mutations and genomic expansion of ERG11 exhibited cross-resistance to fluconazole and voriconazole. Moreover, the azole-resistant isolates from both the environmental and human commensal niches showed similar genotypes.
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Affiliation(s)
- Tianren Hu
- Department of Infectious Diseases, Huashan Hospital, Shanghai Institute of Infectious Disease and Biosecurity and State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China; Shanghai Engineering Research Center of Industrial Microorganisms, Shanghai, China
| | - Sijia Wang
- Department of Infectious Diseases, Huashan Hospital, Shanghai Institute of Infectious Disease and Biosecurity and State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
| | - Jian Bing
- Department of Infectious Diseases, Huashan Hospital, Shanghai Institute of Infectious Disease and Biosecurity and State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
| | - Qiushi Zheng
- Department of Infectious Diseases, Huashan Hospital, Shanghai Institute of Infectious Disease and Biosecurity and State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
| | - Han Du
- Department of Infectious Diseases, Huashan Hospital, Shanghai Institute of Infectious Disease and Biosecurity and State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China; Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Chao Li
- Department of Infectious Diseases, Huashan Hospital, Shanghai Institute of Infectious Disease and Biosecurity and State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
| | - Zhangyue Guan
- Department of Infectious Diseases, Huashan Hospital, Shanghai Institute of Infectious Disease and Biosecurity and State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China; Shanghai Engineering Research Center of Industrial Microorganisms, Shanghai, China
| | - Feng-Yan Bai
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Clarissa J Nobile
- Department of Molecular and Cell Biology, University of California, Merced, California; Health Sciences Research Institute, University of California, Merced, California
| | - Haiqing Chu
- Department of Respiratory and Critical Care Medicine, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, China; Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, China.
| | - Guanghua Huang
- Department of Infectious Diseases, Huashan Hospital, Shanghai Institute of Infectious Disease and Biosecurity and State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China; Shanghai Engineering Research Center of Industrial Microorganisms, Shanghai, China.
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Arrieta-Aguirre I, Menéndez-Manjón P, Carrano G, Diez A, Fernandez-de-Larrinoa Í, Moragues MD. Molecular Identification of Fungal Species through Multiplex-qPCR to Determine Candidal Vulvovaginitis and Antifungal Susceptibility. J Fungi (Basel) 2023; 9:1145. [PMID: 38132746 PMCID: PMC10744653 DOI: 10.3390/jof9121145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 11/15/2023] [Accepted: 11/21/2023] [Indexed: 12/23/2023] Open
Abstract
Vulvovaginal candidiasis (VVC) is a prevalent condition affecting women worldwide. This study aimed to develop a rapid qPCR assay for the accurate identification of VVC etiological agents and reduced azole susceptibility. One hundred and twenty nine vaginal samples from an outpatient clinic (Bilbao, Spain) were analyzed using culture-based methods and a multiplex qPCR targeting fungal species, which identified Candida albicans as the predominant species (94.2%). Antifungal susceptibility tests revealed reduced azole susceptibility in three (3.48%) isolates. Molecular analysis identified several mutations in genes associated with azole resistance as well as novel mutations in TAC1 and MRR1 genes. In conclusion, we developed a rapid multiplex qPCR assay that detects C. albicans in vulvovaginal specimens and reported new mutations in resistance-related genes that could contribute to azole resistance.
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Affiliation(s)
- Inés Arrieta-Aguirre
- Department of Nursing I, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, 48940 Leioa, Biscay, Spain; (P.M.-M.); (M.-D.M.)
| | - Pilar Menéndez-Manjón
- Department of Nursing I, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, 48940 Leioa, Biscay, Spain; (P.M.-M.); (M.-D.M.)
- Department of Immunology, Microbiology and Parasitology, University of the Basque Country UPV/EHU, 48940 Leioa, Biscay, Spain; (G.C.); (A.D.)
| | - Giulia Carrano
- Department of Immunology, Microbiology and Parasitology, University of the Basque Country UPV/EHU, 48940 Leioa, Biscay, Spain; (G.C.); (A.D.)
| | - Ander Diez
- Department of Immunology, Microbiology and Parasitology, University of the Basque Country UPV/EHU, 48940 Leioa, Biscay, Spain; (G.C.); (A.D.)
| | | | - María-Dolores Moragues
- Department of Nursing I, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, 48940 Leioa, Biscay, Spain; (P.M.-M.); (M.-D.M.)
- IIS BioCruces Bizkaia, 48903 Barakaldo, Biscay, Spain
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Miron-Ocampo A, Beattie SR, Guin S, Conway T, Meyers MJ, Moye-Rowley WS, Krysan DJ. CWHM-974 is a fluphenazine derivative with improved antifungal activity against Candida albicans due to reduced susceptibility to multidrug transporter-mediated resistance mechanisms. Antimicrob Agents Chemother 2023; 67:e0056723. [PMID: 37702508 PMCID: PMC10583685 DOI: 10.1128/aac.00567-23] [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: 05/01/2023] [Accepted: 06/18/2023] [Indexed: 09/14/2023] Open
Abstract
Multidrug resistance (MDR) transporters such as ATP-Binding Cassette (ABC) and Major Facilitator Superfamily proteins are important mediators of antifungal drug resistance, particularly with respect to azole class drugs. Consequently, identifying molecules that are not susceptible to this mechanism of resistance is an important goal for new antifungal drug discovery. As part of a project to optimize the antifungal activity of clinically used phenothiazines, we synthesized a fluphenazine derivative (CWHM-974) with 8-fold higher activity against Candida spp. compared to the fluphenazine and with activity against Candida spp. with reduced fluconazole susceptibility due to increased MDR transporters. Here, we show that the improved C. albicans activity is because fluphenazine induces its own resistance by triggering expression of Candida drug resistance (CDR) transporters while CWHM-974 induces expression but does not appear to be a substrate for the transporters or is insensitive to their effects through other mechanisms. We also found that fluphenazine and CWHM-974 are antagonistic with fluconazole in C. albicans but not in C. glabrata, despite inducing CDR1 expression to high levels. Overall, CWHM-974 is one of the few examples of a molecule in which relatively small structural modifications significantly reduced susceptibility to multidrug transporter-mediated resistance.
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Affiliation(s)
- Aracely Miron-Ocampo
- Microbiology/Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Sarah R. Beattie
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Soumitra Guin
- Department of Chemistry, Saint Louis University, Saint Louis, Missouri, USA
| | - Thomas Conway
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA
| | - Marvin J. Meyers
- Department of Chemistry, Saint Louis University, Saint Louis, Missouri, USA
| | - W. Scott Moye-Rowley
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA
| | - Damian J. Krysan
- Microbiology/Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA
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Rabaan AA, Eljaaly K, Alfouzan WA, Mutair AA, Alhumaid S, Alfaraj AH, Aldawood Y, Alsaleh AA, Albayat H, Azmi RA, AlKaabi N, Alzahrani SJ, AlBahrani S, Sulaiman T, Alshukairi AN, Abuzaid AA, Garout M, Ahmad R, Muhammad J. Psychogenetic, genetic and epigenetic mechanisms in Candida auris: Role in drug resistance. J Infect Public Health 2023; 16:257-263. [PMID: 36608452 DOI: 10.1016/j.jiph.2022.12.012] [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] [Received: 06/10/2022] [Revised: 10/28/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022] Open
Abstract
In recent years, we are facing the challenge of drug resistance emergence in fungi. The availability of limited antifungals and development of multi-drug resistance in fungal pathogens has become a serious concern in the past years in the health sector. Although several cellular, molecular, and genetic mechanisms have been proposed to explain the drug resistance mechanism in fungi, but a complete understanding of the molecular and genetic mechanisms is still lacking. Besides the genetic mechanism, epigenetic mechanisms are pivotal in the fungal lifecycle and disease biology. However, very little is understood about the role of epigenetic mechanisms in the emergence of multi-drug resistance in fungi, especially in Candida auris (C. auris). The current narrative review summaries the clinical characteristics, genomic organization, and molecular/genetic/epigenetic mechanisms underlying the emergence of drug resistance in C. auris. A very few studies have attempted to evaluate the role of epigenetic mechanisms in C. auris. Furthermore, advanced genetic tools such as the CRISP-Cas9 system can be utilized to elucidate the epigenetic mechanisms and their role in the emergence of multi-drug resistance in C. auris.
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Affiliation(s)
- Ali A Rabaan
- Molecular Diagnostic Laboratory, Johns Hopkins Aramco Healthcare, Dhahran 31311, Saudi Arabia; College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia; Department of Public Health and Nutrition, The University of Haripur, Haripur 22610, Pakistan.
| | - Khalid Eljaaly
- Department of Pharmacy Practice, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia; Pharmacy Practice and Science Department, College of Pharmacy, University of Arizona, Tucson, AZ, USA
| | - Wadha A Alfouzan
- Department of Microbiology, Faculty of Medicine, Kuwait University, Safat 13110, Kuwait; Microbiology Unit, Department of Laboratories, Farwania Hospital, Farwania 85000, Kuwait
| | - Abbas Al Mutair
- Research Center, Almoosa Specialist Hospital, Al-Ahsa 36342, Saudi Arabia; College of Nursing, Princess Norah Bint Abdulrahman University, Riyadh 11564, Saudi Arabia; School of Nursing, Wollongong University, Wollongong, NSW 2522, Australia; Nursing Department, Prince Sultan Military College of Health Sciences, Dhahran 33048, Saudi Arabia
| | - Saad Alhumaid
- Administration of Pharmaceutical Care, Al-Ahsa Health Cluster, Ministry of Health, Al-Ahsa 31982, Saudi Arabia
| | - Amal H Alfaraj
- Pediatric Department, Abqaiq General Hospital, First Eastern Health Cluster, Abqaiq 33261, Saudi Arabia
| | - Yahya Aldawood
- Clinical Laboratory Science Department, Mohammed Al-Mana College for Medical Sciences, Dammam 34222, Saudi Arabia
| | - Abdulmonem A Alsaleh
- Clinical Laboratory Science Department, Mohammed Al-Mana College for Medical Sciences, Dammam 34222, Saudi Arabia
| | - Hawra Albayat
- Infectious Disease Department, King Saud Medical City, Riyadh 7790, Saudi Arabia
| | - Reyouf Al Azmi
- Infection Prevention and Control, Eastern Health Cluster, Dammam 32253, Saudi Arabia
| | - Nawal AlKaabi
- Sheikh Khalifa Medical City, Abu Dhabi Health Services Company (SEHA), Abu Dhabi, 51900, United Arab Emirates; College of Medicine and Health Science, Khalifa University, Abu Dhabi, 127788, United Arab Emirates
| | - Samira J Alzahrani
- Molecular Diagnostic Laboratory, King Fahd Military Medical Complex, Dhahran 31932, Saudi Arabia
| | - Salma AlBahrani
- Infectious Disease Unit, Specialty Internal Medicine, King Fahd Military Medical Complex, Dhahran 31932, Saudi Arabia
| | - Tarek Sulaiman
- Infectious Diseases Section, Medical Specialties Department, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Abeer N Alshukairi
- College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia; Department of Medicine, King Faisal Specialist Hospital and Research Center, Jeddah, Saudi Arabia
| | - Abdulmonem A Abuzaid
- Medical Microbiology Department, Security Forces Hospital Programme, Dammam 32314, Saudi Arabia
| | - Mohammed Garout
- Department of Community Medicine and Health Care for Pilgrims, Faculty of Medicine, Umm Al-Qura University, Makkah 21955, Saudi Arabia
| | - Rafiq Ahmad
- Department of Microbiology, The University of Haripur, Haripur 22610, Pakistan
| | - Javed Muhammad
- Department of Microbiology, The University of Haripur, Haripur 22610, Pakistan.
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Rapid Hypothesis Testing in Candida albicans Clinical Isolates Using a Cloning-Free, Modular, and Recyclable System for CRISPR-Cas9 Mediated Mutant and Revertant Construction. Microbiol Spectr 2022; 10:e0263021. [PMID: 35612314 PMCID: PMC9241802 DOI: 10.1128/spectrum.02630-21] [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] [Indexed: 11/20/2022] Open
Abstract
As increasing evidence emerges that interstrain genetic diversity among Candida albicans clinical isolates underpins phenotypic variation compared to the reference isolate SC5314, new genetic tools are required to interrogate gene function across strain backgrounds. Here, the SAT1-flipper plasmid was reengineered to contain a C. albicans codon optimized hygromycin B resistance gene (CaHygB). Cassettes were PCR-amplified from both SAT1-flipper and CaHygB-flipper plasmids using primers with homologous sequences flanking target genes of interest to serve as repair templates. Ribonucleoprotein (RNP) complexes containing proprietary CRISPR RNAs (crRNAs), universal transactivating CRISPR RNA (tracrRNA), and Cas9 protein were assembled in vitro and transformed, along with both repair templates, by electroporation into C. albicans. Homozygous deletion of the ADE2 gene results in red-pigmented colonies and this gene was used to validate our approach. Both in SC5314 and a variety of clinical isolates (529L, JS15, SJCA1, TW1), homozygous gene targeting was nearly 100% when plating on media containing nourseothricin and hygromycin B with transformation efficiencies exceeding 104 homozygous deletion mutants per μg of DNA. A gene reversion system was also employed with plasmids pDUP3 and pDIS3 engineered to contain the ADH1 terminator and an overlap extension PCR-mediated approach combined with CRISPR-Cas9 targeting at the NEUT5 neutral locus. A variety of single or compound mutants (Δ/Δals3, Δ/Δcph1 Δ/Δefg1, Δ/Δece1) and their revertant strains were constructed and phenotypically validated by a variety of assays, including biofilm formation, hyphal growth, and macrophage IL-1β response. Thus, we have established a cloning-free, modular system for highly efficient homozygous gene deletion and reversion in diverse isolates. IMPORTANCE Recently, phenotypic heterogeneity in Candida albicans isolates has been recognized as an underappreciated factor contributing to gene diversification and broadly impacts strain-to-strain antifungal resistance, fitness, and pathogenicity. We have designed a cloning-free genetic system for rapid gene deletion and reversion in C. albicans clinical isolates that interlaces established recyclable genetic systems with CRISPR-Cas9 technology. The SAT1-flipper was reengineered to contain CaHygB encoding resistance to hygromycin B. Using a modular PCR-mediated approach coupled with in vitro ribonucleoprotein assembly with commercial reagents, both SAT1- and CaHygB-flipper cassettes were simultaneously integrated at loci with high efficiency (104 transformants per μg DNA) and upward of 99% homozygous gene targeting across a collection of diverse isolates of various anatomical origin. Revertant strains were constructed by overlap extension PCR with CRISPR-Cas9 targeted integration at the NEUT5 locus. Thus, this facile system will aid in unraveling the genetic factors contributing to the complexity of intraspecies diversity.
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A Proteomic Landscape of Candida albicans in the Stepwise Evolution to Fluconazole Resistance. Antimicrob Agents Chemother 2022; 66:e0210521. [PMID: 35343782 DOI: 10.1128/aac.02105-21] [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] [Indexed: 12/29/2022] Open
Abstract
As an opportunistic fungal pathogen, Candida albicans is a major cause of superficial and systemic infections in immunocompromised patients. The increasing rate of azole resistance in C. albicans has brought further challenges to clinical therapy. In this study, we collected five isogenic C. albicans strains recovered over discrete intervals from an HIV-infected patient who suffered 2-year recurrent oropharyngeal candidiasis. Azole resistance was known from the clinical history to have developed gradually in this patient, and this was confirmed by MIC assays of each strain. Proteomic techniques can be used to investigate more comprehensively how resistance develops in pathogenic fungi over time. Our study is the first to use tandem mass tag (TMT) labeling combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) technology to investigate the acquired resistance mechanisms of serial C. albicans isolates at the proteomic level. A total of 4,029 proteins have been identified, of which 3,766 have been quantified. Compared with Ca1, bioinformatics analysis showed that differentially expressed proteins were mainly associated with aspects such as the downregulation of glycolysis/gluconeogenesis, pyruvate metabolism, fatty acid degradation, and oxidative stress response proteins in all four subsequent strains but, remarkably, the activation of amino acid metabolism in Ca8 and Ca14 and increased protection against osmotic stress or excessive copper toxicity, upregulation of respiratory chain activity, and suppression of iron transport in Ca17. By tracing proteomic alterations in this set of isogenic resistance isolates, we acquire mechanistic insight into the steps involved in the acquisition of azole resistance in C. albicans.
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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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Uthayakumar D, Sharma J, Wensing L, Shapiro RS. CRISPR-Based Genetic Manipulation of Candida Species: Historical Perspectives and Current Approaches. Front Genome Ed 2021; 2:606281. [PMID: 34713231 PMCID: PMC8525362 DOI: 10.3389/fgeed.2020.606281] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 12/09/2020] [Indexed: 12/26/2022] Open
Abstract
The Candida genus encompasses a diverse group of ascomycete fungi that have captured the attention of the scientific community, due to both their role in pathogenesis and emerging applications in biotechnology; the development of gene editing tools such as CRISPR, to analyze fungal genetics and perform functional genomic studies in these organisms, is essential to fully understand and exploit this genus, to further advance antifungal drug discovery and industrial value. However, genetic manipulation of Candida species has been met with several distinctive barriers to progress, such as unconventional codon usage in some species, as well as the absence of a complete sexual cycle in its diploid members. Despite these challenges, the last few decades have witnessed an expansion of the Candida genetic toolbox, allowing for diverse genome editing applications that range from introducing a single point mutation to generating large-scale mutant libraries for functional genomic studies. Clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 technology is among the most recent of these advancements, bringing unparalleled versatility and precision to genetic manipulation of Candida species. Since its initial applications in Candida albicans, CRISPR-Cas9 platforms are rapidly evolving to permit efficient gene editing in other members of the genus. The technology has proven useful in elucidating the pathogenesis and host-pathogen interactions of medically relevant Candida species, and has led to novel insights on antifungal drug susceptibility and resistance, as well as innovative treatment strategies. CRISPR-Cas9 tools have also been exploited to uncover potential applications of Candida species in industrial contexts. This review is intended to provide a historical overview of genetic approaches used to study the Candida genus and to discuss the state of the art of CRISPR-based genetic manipulation of Candida species, highlighting its contributions to deciphering the biology of this genus, as well as providing perspectives for the future of Candida genetics.
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Affiliation(s)
- Deeva Uthayakumar
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Jehoshua Sharma
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Lauren Wensing
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Rebecca S Shapiro
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
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11
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Uddin W, Dhabalia D, Prakash SMU, Kabir MA. Systematic truncations of chromosome 4 and their responses to antifungals in Candida albicans. J Genet Eng Biotechnol 2021; 19:92. [PMID: 34152516 PMCID: PMC8217416 DOI: 10.1186/s43141-021-00197-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 06/10/2021] [Indexed: 01/08/2023]
Abstract
BACKGROUND Candida albicans is an opportunistic human fungal pathogen responsible for superficial and systemic life-threatening infections. Treating these infections is challenging as many clinical isolates show increased drug resistance to antifungals. Chromosome (Chr) 4 monosomy was implicated in a fluconazole-resistant mutant. However, exposure to fluconazole adversely affects Candida cells and can generate numerous mutations. Hence, the present study aimed to truncate Chr4 and challenge the generated Candida strains to antifungals and evaluate their role in drug response. RESULTS Herein, Chr4 was truncated in C. albicans using the telomere-mediated chromosomal truncation method. The resulting eight Candida strains carrying one truncated homolog of Chr4 were tested for response to multiple antifungals. The minimal inhibitory concentration (MIC) for these strains was determined against three classes of antifungals. The MIC values against fluconazole, amphotericin B, and caspofungin were closer to that of the wild type strain. Microdilution assay against fluconazole showed that the mutants and wild type strains had similar sensitivity to fluconazole. The disc diffusion assay against five azoles and two polyenes revealed that the zones of inhibition for all the eight strains were similar to those of the wild type. Thus, none of the generated strains showed any significant resistance to the tested antifungals. However, spot assay exhibited a reasonably high tolerance of a few generated strains with increasing concentrations of fluconazole. CONCLUSION This analysis suggested that Chr4 aneuploidy might not underlie drug resistance but rather drug tolerance in Candida albicans.
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Affiliation(s)
- Wasim Uddin
- Molecular Genetics Laboratory, School of Biotechnology, National Institute of Technology Calicut, Calicut, Kerala, 673601, India
| | - Darshan Dhabalia
- Molecular Genetics Laboratory, School of Biotechnology, National Institute of Technology Calicut, Calicut, Kerala, 673601, India
| | - S M Udaya Prakash
- Molecular Genetics Laboratory, School of Biotechnology, National Institute of Technology Calicut, Calicut, Kerala, 673601, India
| | - M Anaul Kabir
- Molecular Genetics Laboratory, School of Biotechnology, National Institute of Technology Calicut, Calicut, Kerala, 673601, India.
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12
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Nishimoto AT, Sharma C, Rogers PD. Molecular and genetic basis of azole antifungal resistance in the opportunistic pathogenic fungus Candida albicans. J Antimicrob Chemother 2021; 75:257-270. [PMID: 31603213 DOI: 10.1093/jac/dkz400] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Candida albicans is an opportunistic yeast and the major human fungal pathogen in the USA, as well as in many other regions of the world. Infections with C. albicans can range from superficial mucosal and dermatological infections to life-threatening infections of the bloodstream and vital organs. The azole antifungals remain an important mainstay treatment of candidiasis and therefore the investigation and understanding of the evolution, frequency and mechanisms of azole resistance are vital to improving treatment strategies against this organism. Here the organism C. albicans and the genetic changes and molecular bases underlying the currently known resistance mechanisms to the azole antifungal class are reviewed, including up-regulated expression of efflux pumps, changes in the expression and amino acid composition of the azole target Erg11 and alterations to the organism's typical sterol biosynthesis pathways. Additionally, we update what is known about activating mutations in the zinc cluster transcription factor (ZCF) genes regulating many of these resistance mechanisms and review azole import as a potential contributor to azole resistance. Lastly, investigations of azole tolerance in C. albicans and its implicated clinical significance are reviewed.
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Affiliation(s)
- Andrew T Nishimoto
- Department of Clinical Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Cheshta Sharma
- Department of Clinical Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
| | - P David Rogers
- Department of Clinical Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
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13
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Suchodolski J, Krasowska A. Fructose Induces Fluconazole Resistance in Candida albicans through Activation of Mdr1 and Cdr1 Transporters. Int J Mol Sci 2021; 22:ijms22042127. [PMID: 33669913 PMCID: PMC7924610 DOI: 10.3390/ijms22042127] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 02/16/2021] [Accepted: 02/18/2021] [Indexed: 12/12/2022] Open
Abstract
Candida albicans is a pathogenic fungus that is increasingly developing multidrug resistance (MDR), including resistance to azole drugs such as fluconazole (FLC). This is partially a result of the increased synthesis of membrane efflux transporters Cdr1p, Cdr2p, and Mdr1p. Although all these proteins can export FLC, only Cdr1p is expressed constitutively. In this study, the effect of elevated fructose, as a carbon source, on the MDR was evaluated. It was shown that fructose, elevated in the serum of diabetics, promotes FLC resistance. Using C. albicans strains with green fluorescent protein (GFP) tagged MDR transporters, it was determined that the FLC-resistance phenotype occurs as a result of Mdr1p activation and via the increased induction of higher Cdr1p levels. It was observed that fructose-grown C. albicans cells displayed a high efflux activity of both transporters as opposed to glucose-grown cells, which synthesize Cdr1p but not Mdr1p. Additionally, it was concluded that elevated fructose serum levels induce the de novo production of Mdr1p after 60 min. In combination with glucose, however, fructose induces Mdr1p production as soon as after 30 min. It is proposed that fructose may be one of the biochemical factors responsible for Mdr1p production in C. albicans cells.
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14
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Feng W, Yang J, Ji Y, Xi Z, Yang L, Zhu X, Ma Y. Mrr2
mutations and upregulation are associated with increased fluconazole resistance in
Candida albicans
isolates from patients with vulvovaginal candidiasis. Lett Appl Microbiol 2019; 70:95-101. [PMID: 31705810 DOI: 10.1111/lam.13248] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 11/05/2019] [Accepted: 11/06/2019] [Indexed: 11/26/2022]
Affiliation(s)
- W. Feng
- The Department of Dermatovenereology The Second Hospital of Shanxi Medical University Taiyuan Shanxi China
| | - J. Yang
- The Department of Dermatovenereology The Second Hospital of Shanxi Medical University Taiyuan Shanxi China
| | - Y. Ji
- The Department of Dermatovenereology The Second Hospital of Shanxi Medical University Taiyuan Shanxi China
| | - Z. Xi
- The Department of Dermatovenereology The Second Hospital of Shanxi Medical University Taiyuan Shanxi China
| | - L. Yang
- The Department of Dermatovenereology The Second Hospital of Shanxi Medical University Taiyuan Shanxi China
| | - X. Zhu
- The Department of Dermatovenereology The Second Hospital of Shanxi Medical University Taiyuan Shanxi China
| | - Y. Ma
- The Department of Dermatovenereology The Second Hospital of Shanxi Medical University Taiyuan Shanxi China
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