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Mulet-Bayona JV, Cancino-Muñoz I, Salvador-García C, Tormo-Palop N, Guna-Serrano MDR, Ferrer-Gómez C, Melero-García M, González-Candelas F, Gimeno-Cardona C. Genotypic and phenotypic characterisation of a nosocomial outbreak of Candida auris in Spain during 5 years. Mycoses 2024; 67:e13776. [PMID: 39086009 DOI: 10.1111/myc.13776] [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: 06/11/2024] [Revised: 07/22/2024] [Accepted: 07/23/2024] [Indexed: 08/02/2024]
Abstract
OBJECTIVES The investigation of Candida auris outbreaks is needed to provide insights into its population structure and transmission dynamics. We genotypically and phenotypically characterised a C. auris nosocomial outbreak occurred in Consorcio Hospital General Universitario de Valencia (CHGUV), Spain. METHODS Data and isolates were collected from CHGUV from September 2017 (first case) until September 2021. Thirty-five isolates, including one from an environmental source, were randomly selected for whole genome sequencing (WGS), and the genomes were analysed along with a database with 335 publicly available genomes, assigning them to one of the five major clades. In order to identify polymorphisms associated with drug resistance, we used the fully susceptible GCA_003014415.1 strain as reference sequence. Known mutations in genes ERG11 and FKS1 conferring resistance to fluconazole and echinocandins, respectively, were investigated. Isolates were classified into aggregating or non-aggregating. RESULTS All isolates belonged to clade III and were from an outbreak with a single origin. They clustered close to three publicly available genomes from a hospital from where the first patient was transferred, being the probable origin. The mutation VF125AL in the ERG11 gene, conferring resistance to fluconazole, was present in all the isolates and one isolate also carried the mutation S639Y in the FKS1 gene. All the isolates had a non-aggregating phenotype (potentially more virulent). CONCLUSIONS Isolates are genotypically related and phenotypically identical but one with resistance to echinocandins, which seems to indicate that they all belong to an outbreak originated from a single isolate, remaining largely invariable over the years. This result stresses the importance of implementing infection control practices as soon as the first case is detected or when a patient is transferred from a setting with known cases.
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Affiliation(s)
- Juan Vicente Mulet-Bayona
- Servicio de Microbiología y Parasitología, Consorcio Hospital General Universitario de Valencia, Valencia, Spain
| | - Irving Cancino-Muñoz
- Unidad Mixta Infección y Salud Pública FISABIO-Universidad de Valencia, Valencia, Spain
- Instituto de Biología Integrativa de Sistemas, I2SysBio (CSIC-UV), Valencia, Spain
| | - Carme Salvador-García
- Servicio de Microbiología y Parasitología, Consorcio Hospital General Universitario de Valencia, Valencia, Spain
| | - Nuria Tormo-Palop
- Servicio de Microbiología y Parasitología, Consorcio Hospital General Universitario de Valencia, Valencia, Spain
| | - María Del Remedio Guna-Serrano
- Servicio de Microbiología y Parasitología, Consorcio Hospital General Universitario de Valencia, Valencia, Spain
- Departamento de Microbiología y Ecología, Universidad de Valencia, Valencia, Spain
| | - Carolina Ferrer-Gómez
- Servicio de Anestesiología, Reanimación y Terapéutica del Dolor, Consorcio Hospital General Universitario de Valencia, Valencia, Spain
| | - Mercedes Melero-García
- Servicio de Medicina Preventiva, Consorcio Hospital General Universitario de Valencia, Valencia, Spain
| | - Fernando González-Candelas
- Unidad Mixta Infección y Salud Pública FISABIO-Universidad de Valencia, Valencia, Spain
- Instituto de Biología Integrativa de Sistemas, I2SysBio (CSIC-UV), Valencia, Spain
- CIBER en Epidemiología y Salud Pública, ISCIII, Madrid, Spain
| | - Concepción Gimeno-Cardona
- Servicio de Microbiología y Parasitología, Consorcio Hospital General Universitario de Valencia, Valencia, Spain
- Departamento de Microbiología y Ecología, Universidad de Valencia, Valencia, Spain
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Mantzana P, Protonotariou E, Meletis G, Tychala A, Skoura L. The Micronaut-AM antifungal susceptibility testing method does not overestimate amphotericin B resistance in Candida auris. Microbiol Spectr 2024; 12:e0049024. [PMID: 38578100 PMCID: PMC11064516 DOI: 10.1128/spectrum.00490-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 03/15/2024] [Indexed: 04/06/2024] Open
Affiliation(s)
- Paraskevi Mantzana
- Department of Microbiology, AHEPA University Hospital, Thessaloniki, Greece
| | | | - Georgios Meletis
- Department of Microbiology, AHEPA University Hospital, Thessaloniki, Greece
| | - Areti Tychala
- Department of Microbiology, AHEPA University Hospital, Thessaloniki, Greece
| | - Lemonia Skoura
- Department of Microbiology, AHEPA University Hospital, Thessaloniki, Greece
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Siopi M, Pachoulis I, Leventaki S, Spruijtenburg B, Meis JF, Pournaras S, Vrioni G, Tsakris A, Meletiadis J. Evaluation of the Vitek 2 system for antifungal susceptibility testing of Candida auris using a representative international panel of clinical isolates: overestimation of amphotericin B resistance and underestimation of fluconazole resistance. J Clin Microbiol 2024; 62:e0152823. [PMID: 38501836 PMCID: PMC11005389 DOI: 10.1128/jcm.01528-23] [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: 11/16/2023] [Accepted: 02/21/2024] [Indexed: 03/20/2024] Open
Abstract
Although the Vitek 2 system is broadly used for antifungal susceptibility testing of Candida spp., its performance against Candida auris has been assessed using limited number of isolates recovered from restricted geographic areas. We therefore compared Vitek 2 system with the reference Clinical and Laboratory Standards Institute (CLSI) broth microdilution method using an international collection of 100 C. auris isolates belonging to different clades. The agreement ±1 twofold dilution between the two methods and the categorical agreement (CA) based on the Centers for Disease Control and Prevention's (CDC's) tentative resistance breakpoints and Vitek 2-specific wild-type upper limit values (WT-ULVs) were determined. The CLSI-Vitek 2 agreement was poor for 5-flucytosine (0%), fluconazole (16%), and amphotericin B (29%), and moderate for voriconazole (61%), micafungin (67%), and caspofungin (81%). Significant interpretation errors were recorded using the CDC breakpoints for amphotericin B (31% CA, 69% major errors; MaEs) and fluconazole (69% CA, 31% very major errors; VmEs), but not for echinocandins (99% CA, 1% MaEs for both micafungin and caspofungin) for which the Vitek 2 allowed correct categorization of echinocandin-resistant FKS1 mutant isolates. Discrepancies were reduced when the Vitek 2 WT-ULV of 16 mg/L for amphotericin B (98% CA, 2% MaEs) and of 4 mg/L for fluconazole (96% CA, 1% MaEs, 3% VmEs) were used. In conclusion, the Vitek 2 system performed well for echinocandin susceptibility testing of C .auris. Resistance to fluconazole was underestimated whereas resistance to amphotericin B was overestimated using the CDC breakpoints of ≥32 and ≥2 mg/L, respectively. Vitek 2 minimun inhibitory concentrations (MICs) >4 mg/L indicated resistance to fluconazole and Vitek 2 MICs ≤16 mg/L indicated non-resistance to amphotericin B.
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Affiliation(s)
- Maria Siopi
- Clinical Microbiology Laboratory, “Attikon” University General Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
- Molecular Microbiology and Immunology Laboratory, Department of Biomedical Sciences, University of West Attica, Athens, Greece
| | - Ioannis Pachoulis
- Clinical Microbiology Laboratory, “Attikon” University General Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
- Molecular Microbiology and Immunology Laboratory, Department of Biomedical Sciences, University of West Attica, Athens, Greece
| | - Sevasti Leventaki
- Clinical Microbiology Laboratory, “Attikon” University General Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
- Molecular Microbiology and Immunology Laboratory, Department of Biomedical Sciences, University of West Attica, Athens, Greece
| | - Bram Spruijtenburg
- Canisius-Wilhelmina Hospital (CWZ)/Dicoon, Nijmegen, the Netherlands
- Radboudumc-CWZ Center of Expertise for Mycology, Nijmegen, the Netherlands
| | - Jacques F. Meis
- Radboudumc-CWZ Center of Expertise for Mycology, Nijmegen, the Netherlands
- Institute of Translational Research, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Excellence Center for Medical Mycology (ECMM), University of Cologne, Cologne, Germany
| | - Spyros Pournaras
- Clinical Microbiology Laboratory, “Attikon” University General Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Georgia Vrioni
- Department of Microbiology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Athanasios Tsakris
- Department of Microbiology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Joseph Meletiadis
- Clinical Microbiology Laboratory, “Attikon” University General Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
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Spruijtenburg B, de Souza Lima BJF, Tosar STG, Borman AM, Andersen CT, Nizamuddin S, Ahmad S, de Almeida Junior JN, Vicente VA, Nosanchuk JD, Buil JB, de Hoog S, Meijer EFJ, Meis JF, de Groot T. The yeast genus Tardiomyces gen. nov. with one new species and two new combinations. Infection 2024:10.1007/s15010-024-02229-6. [PMID: 38573472 DOI: 10.1007/s15010-024-02229-6] [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: 12/18/2023] [Accepted: 03/05/2024] [Indexed: 04/05/2024]
Abstract
PURPOSE Rare yeasts species are increasingly reported as causative agents of invasive human infection. Proper identification and antifungal therapy are essential to manage these infections. Candida blankii is one of these emerging pathogens and is known for its reduced susceptibility to multiple antifungals. METHODS To obtain more insight into the characteristics of this species, 26 isolates reported as C. blankii were investigated using genetic and phenotypical approaches. RESULTS Among the 26 isolates, seven recovered either from blood, sputum, urine, or the oral cavity, displayed substantial genetic and some phenotypical differences compared to the other isolates, which were confirmed as C. blankii. We consider these seven strains to represent a novel species, Tardiomyces depauwii. Phylogenomics assigned C. blankii, C. digboiensis, and the novel species in a distinct branch within the order Dipodascales, for which the novel genus Tardiomyces is erected. The new combinations Tardiomyces blankii and Tardiomyces digboiensis are introduced. Differences with related, strictly environmental genera Sugiyamaella, Crinitomyces, and Diddensiella are enumerated. All three Tardiomyces species share the rare ability to grow up to 42 °C, display slower growth in nutrient-poor media, and show a reduced susceptibility to azoles and echinocandins. Characteristics of T. depauwii include high MIC values with voriconazole and a unique protein pattern. CONCLUSION We propose the novel yeast species Tardiomyces depauwii and the transfer of C. blankii and C. digboiensis to the novel Tardiomyces genus.
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Affiliation(s)
- Bram Spruijtenburg
- Department of Medical Microbiology, Radboudumc, Nijmegen, The Netherlands.
- Radboudumc-CWZ Center of Expertise for Mycology, Nijmegen, The Netherlands.
- Canisius-Wilhelmina Hospital (CWZ)/Dicoon, Nijmegen, The Netherlands.
| | - Bruna Jacomel Favoreto de Souza Lima
- Radboudumc-CWZ Center of Expertise for Mycology, Nijmegen, The Netherlands
- Canisius-Wilhelmina Hospital (CWZ)/Dicoon, Nijmegen, The Netherlands
- Microbiology, Parasitology and Pathology Post-Graduation Program, Department of Pathology, Federal University of Paraná, Curitiba, Paraná, Brazil
| | - Sonia T Granadillo Tosar
- Radboudumc-CWZ Center of Expertise for Mycology, Nijmegen, The Netherlands
- Canisius-Wilhelmina Hospital (CWZ)/Dicoon, Nijmegen, The Netherlands
| | - Andrew M Borman
- UK Health Security Agency National Mycology Reference Laboratory, Southmead Hospital, Bristol, BS10 5NB, UK
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, EX4 4QD, UK
| | | | - Summiya Nizamuddin
- Section of Microbiology, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan
| | - Suhail Ahmad
- Department of Microbiology, Faculty of Medicine, Kuwait University, Safat, Kuwait
| | | | - Vânia Aparecida Vicente
- Microbiology, Parasitology and Pathology Post-Graduation Program, Department of Pathology, Federal University of Paraná, Curitiba, Paraná, Brazil
- Bioprocess Engineering and Biotechnology Graduate Program, Federal University of Paraná, Curitiba, Brazil
- Microbiological Collections of Paraná Network (CMRP/Taxonline), Department of Basic Pathology, Federal University of Paraná, Curitiba, Brazil
| | - Joshua D Nosanchuk
- Department of Medicine (Division of Infectious Diseases) and Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | - Jochem B Buil
- Department of Medical Microbiology, Radboudumc, Nijmegen, The Netherlands
- Radboudumc-CWZ Center of Expertise for Mycology, Nijmegen, The Netherlands
| | - Sybren de Hoog
- Radboudumc-CWZ Center of Expertise for Mycology, Nijmegen, The Netherlands
- Microbiology, Parasitology and Pathology Post-Graduation Program, Department of Pathology, Federal University of Paraná, Curitiba, Paraná, Brazil
| | - Eelco F J Meijer
- Department of Medical Microbiology, Radboudumc, Nijmegen, The Netherlands
- Radboudumc-CWZ Center of Expertise for Mycology, Nijmegen, The Netherlands
- Canisius-Wilhelmina Hospital (CWZ)/Dicoon, Nijmegen, The Netherlands
| | - Jacques F Meis
- Department of Medical Microbiology, Radboudumc, Nijmegen, The Netherlands
- Radboudumc-CWZ Center of Expertise for Mycology, Nijmegen, The Netherlands
- Institute of Translational Research, Cologne Excellence Cluster On Cellular Stress Responses in Aging-Associated Diseases (CECAD) and Excellence Center for Medical Mycology, University of Cologne, Cologne, Germany
| | - Theun de Groot
- Radboudumc-CWZ Center of Expertise for Mycology, Nijmegen, The Netherlands
- Canisius-Wilhelmina Hospital (CWZ)/Dicoon, Nijmegen, The Netherlands
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Thomsen J, Abdulrazzaq NM, Oulhaj A, Nyasulu PS, Alatoom A, Denning DW, Al Dhaheri F, Menezes GA, Moubareck CA, Senok A, Everett DB. Emergence of highly resistant Candida auris in the United Arab Emirates: a retrospective analysis of evolving national trends. Front Public Health 2024; 11:1244358. [PMID: 38292390 PMCID: PMC10826512 DOI: 10.3389/fpubh.2023.1244358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 11/08/2023] [Indexed: 02/01/2024] Open
Abstract
Introduction The Centers for Disease Prevention and Control lists Candida auris, given its global emergence, multidrug resistance, high mortality, and persistent transmissions in health care settings as one of five urgent threats. As a new threat, the need for surveillance of C. auris is critical. This is particularly important for a cosmopolitan setting and global hub such as the United Arab Emirates (UAE) where continued introduction and emergence of resistant variant strains is a major concern. Methods The United Arab Emirates has carried out a 12 years of antimicrobial resistance surveillance (2010-2021) across the country, spanning all seven Emirates. A retrospective analysis of C. auris emergence from 2018-2021 was undertaken, utilising the demographic and microbiological data collected via a unified WHONET platform for AMR surveillance. Results Nine hundred eight non-duplicate C. auris isolates were reported from 2018-2021. An exponential upward trend of cases was found. Most isolates were isolated from urine, blood, skin and soft tissue, and the respiratory tract. UAE nationals nationals comprised 29% (n = 186 of 632) of all patients; the remainder were from 34 other nations. Almost all isolates were from inpatient settings (89.0%, n = 809). The cases show widespread distribution across all reporting sites in the country. C. auris resistance levels remained consistently high across all classes of antifungals used. C. auris in this population remains highly resistant to azoles (fluconazole, 72.6% in 2021) and amphotericin. Echinocandin resistance has now emerged and is increasing annually. There was no statistically significant difference in mortality between Candida auris and Candida spp. (non-auris) patients (p-value: 0.8179), however Candida auris patients had a higher intensive care unit (ICU) admission rate (p-value <0.0001) and longer hospital stay (p < 0.0001) compared to Candida spp. (non-auris) patients. Conclusion The increasing trend of C. auris detection and associated multidrug resistant phenotypes in the UAE is alarming. Continued C. auris circulation in hospitals requires enhanced infection control measures to prevent continued dissemination.
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Affiliation(s)
- Jens Thomsen
- Department of Environmental and Occupational Health and Safey, Abu Dhabi Publich Health Center, Abu Dhabi, United Arab Emirates
- Department of Pathology and Infectious Diseases, Khalifa University, Abu Dhabi, United Arab Emirates
| | - Najiba M. Abdulrazzaq
- Al Kuwait Hospital Dubai, Emirates Health Services Establishment (EHS), Dubai, United Arab Emirates
| | - Abderrahim Oulhaj
- Department of Epidemiology and Public Health, Khalifa University, Abu Dhabi, United Arab Emirates
| | - Peter S. Nyasulu
- Department of Global Health, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Adnan Alatoom
- Department of Pathology, Sheikh Shakhbout Medical City, Abu Dhabi, United Arab Emirates
| | - David W. Denning
- Manchester Fungal Infection Group, The University of Manchester, Manchester, United Kingdom
| | - Fatima Al Dhaheri
- Department of Pediatrics, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | | | - Godfred Antony Menezes
- Department of Medical Microbiology and Immunology, Ras Al Khaimah Medical and Health Sciences University, Ras Al Khaimah, United Arab Emirates
| | | | - Abiola Senok
- College of Medicine, Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai, United Arab Emirates
- School of Dentistry, Cardiff University, Cardiff, United Kingdom
| | - Dean B. Everett
- Department of Pathology and Infectious Diseases, Khalifa University, Abu Dhabi, United Arab Emirates
- Biotechnology Research Center, Khalifa University, Abu Dhabi, United Arab Emirates
- Infection Research Unit, Khalifa University, Abu Dhabi, United Arab Emirates
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Ahmad S, Asadzadeh M, Al-Sweih N, Khan Z. Spectrum and management of rare Candida/yeast infections in Kuwait in the Middle East. Ther Adv Infect Dis 2024; 11:20499361241263733. [PMID: 39070702 PMCID: PMC11273600 DOI: 10.1177/20499361241263733] [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: 01/18/2024] [Accepted: 06/06/2024] [Indexed: 07/30/2024] Open
Abstract
Invasive fungal infections (IFIs) are associated with high mortality rates and mostly affect patients with compromised immunity. The incidence of IFIs is increasing worldwide with the expanding population of susceptible patients. Candida and other yeast infections represent a major component of IFIs. Rare Candida/yeast infections have also increased in recent years and pose considerable diagnostic and management challenges as they are not easily recognized by routine phenotypic characteristic-based diagnostic methods and/or by the automated yeast identification systems. Rare Candida/yeasts also exhibit reduced susceptibility to antifungal drugs making proper management of invasive infections challenging. Here, we review the diagnosis and management of 60 cases of rare Candida/yeast IFIs described so far in Kuwait, an Arabian Gulf country in the Middle East. Interestingly, majority (34 of 60, 56.7%) of these rare Candida/yeast invasive infections occurred among neonates or premature, very-low-birth-weight neonates, usually following prior bacteremia episodes. The clinical details, treatment given, and outcome were available for 28 of 34 neonates. The crude mortality rate among these neonates was 32.2% as 19 of 28 (67.8%) survived the infection and were discharged in healthy condition, likely due to accurate diagnosis and frequent use of combination therapy. Physicians treating patients with extended stay under intensive care, on mechanical ventilation, receiving broad spectrum antibiotics and with gastrointestinal surgery/complications should proactively investigate IFIs. Timely diagnosis and early antifungal treatment are essential to decrease mortality. Understanding the epidemiology and spectrum of rare Candida/yeast invasive infections in different geographical regions, their susceptibility profiles and management will help to devise novel diagnostic and treatment approaches and formulate guidelines for improved patient outcome.
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Affiliation(s)
- Suhail Ahmad
- Department of Microbiology, Faculty of Medicine, Kuwait University, P.O. Box 24923, Safat 13110, Kuwait
| | - Mohammad Asadzadeh
- Department of Microbiology, Faculty of Medicine, Kuwait University, Jabriya, Kuwait
| | - Noura Al-Sweih
- Department of Microbiology, Faculty of Medicine, Kuwait University, Jabriya, Kuwait
| | - Ziauddin Khan
- Department of Microbiology, Faculty of Medicine, Kuwait University, Jabriya, Kuwait
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Asadzadeh M, Alfouzan W, Parker JE, Meis JF, Kelly SL, Joseph L, Ahmad S. Molecular Characterization and Sterol Profiles Identify Nonsynonymous Mutations in ERG2 as a Major Mechanism Conferring Reduced Susceptibility to Amphotericin B in Candida kefyr. Microbiol Spectr 2023; 11:e0147423. [PMID: 37358415 PMCID: PMC10434000 DOI: 10.1128/spectrum.01474-23] [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: 05/16/2023] [Accepted: 06/01/2023] [Indexed: 06/27/2023] Open
Abstract
The molecular basis of reduced susceptibility to amphotericin B (rs-AMB) among any yeasts is poorly defined. Genetic alterations in genes involved in ergosterol biosynthesis and total cell sterols were investigated among clinical Candida kefyr isolates. C. kefyr isolates (n = 81) obtained from 74 patients in Kuwait and identified by phenotypic and molecular methods were analyzed. An Etest was initially used to identify isolates with rs-AMB. Specific mutations in ERG2 and ERG6 involved in ergosterol biosynthesis were detected by PCR sequencing. Twelve selected isolates were also tested by the SensiTitre Yeast One (SYO), and total cell sterols were evaluated by gas chromatography-mass spectrometry and ERG3 and ERG11 sequencing. Eight isolates from 8 patients showed rs-AMB by Etest, including 2 isolates with additional resistance to fluconazole or to all three antifungals. SYO correctly identified 8 of 8 rs-AMB isolates. A nonsynonymous mutation in ERG2 was detected in 6 of 8 rs-AMB isolates but also in 3 of 73 isolates with a wild-type AMB pattern. One rs-AMB isolate contained a deletion (frameshift) mutation in ERG2. One or more nonsynonymous mutations was detected in ERG6 in 11 of 81 isolates with the rs-AMB or wild-type AMB pattern. Among 12 selected isolates, 2 and 2 isolates contained a nonsynonymous mutation(s) in ERG3 and ERG11, respectively. Ergosterol was undetectable in 7 of 8 rs-AMB isolates, and the total cell sterol profiles were consistent with loss of ERG2 function in 6 rs-AMB isolates and loss of ERG3 activity in another rs-AMB isolate. Our data showed that ERG2 is a major target conferring rs-AMB in clinical C. kefyr isolates. IMPORTANCE Some yeast species exhibit intrinsic resistance or rapidly acquire resistance to azole antifungals. Despite >50 years of clinical use, resistance to amphotericin B (AMB) among yeast species has been extremely rarely reported until recently. Reduced susceptibility to AMB (rs-AMB) among yeast species is, therefore, a matter of serious concern due to the availability of only four classes of antifungal drugs. Recent studies in Candida glabrata, Candida lusitaniae, and Candida auris have identified ERG genes involved in ergosterol biosynthesis as the major targets conferring rs-AMB. The results of this study also show that nonsynonymous mutations in ERG2 impair its function, abolish ergosterol from C. kefyr, and confer rs-AMB. Thus, rapid detection of rs-AMB among clinical isolates will help in proper management of invasive C. kefyr infections.
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Affiliation(s)
- Mohammad Asadzadeh
- Department of Microbiology, Faculty of Medicine, Kuwait University, Safat, Kuwait
| | - Wadha Alfouzan
- Department of Microbiology, Faculty of Medicine, Kuwait University, Safat, Kuwait
| | - Josie E. Parker
- Molecular Biosciences Division, School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Jacques F. Meis
- Department of Medical Microbiology and Infectious Diseases, Canisius-Wilhelmina Hospital, Nijmegen, the Netherlands
- Center of Expertise in Mycology, Radboudumc, Canisius-Wilhelmina Hospital, Nijmegen, the Netherlands
- Department of Internal Medicine, Excellence Center for Medical Mycology, Faculty of Medicine, University Hospital Cologne, Cologne, Germany
| | - Steven L. Kelly
- Institute of Life Science, Faculty of Health, Medicine and Life Sciences, Swansea University, Swansea, Wales, United Kingdom
| | - Leena Joseph
- Department of Microbiology, Faculty of Medicine, Kuwait University, Safat, Kuwait
| | - Suhail Ahmad
- Department of Microbiology, Faculty of Medicine, Kuwait University, Safat, Kuwait
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