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Spruijtenburg B, Rezusta A, Houbraken J, Hagen F, de Groot T, Meis JF, Meijer EFJ. Susceptibility Testing of Environmental and Clinical Aspergillus sydowii Demonstrates Potent Activity of Various Antifungals. Mycopathologia 2024; 189:61. [PMID: 38958798 PMCID: PMC11222195 DOI: 10.1007/s11046-024-00869-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Accepted: 06/13/2024] [Indexed: 07/04/2024]
Abstract
The genus Aspergillus consists of a vast number of medically and environmentally relevant species. Aspergillus species classified in series Versicolores are ubiquitous in the environment and include the opportunistic pathogen Aspergillus sydowii, which is associated with onychomycosis and superficial skin infections. Despite frequent clinical reports of A. sydowii and related series Versicolores species, antifungal susceptibility data are scarce, hampering optimal treatment choices and subsequent patient outcomes. Here, we employed antifungal susceptibility testing (AFST) based on microbroth dilution on a set of 155 series Versicolores strains using the common antifungals amphotericin B, itraconazole, voriconazole, posaconazole, isavuconazole and micafungin with the addition of luliconazole and olorofim. All strains were identified using partial calmodulin gene sequencing, with 145 being A. sydowii, seven A. creber and three A. versicolor, using the latest taxonomic insights. Overall, tested antifungals were potent against the entire strain collection. In comparison to A. fumigatus, azole and amphotericin B MICs were slightly elevated for some strains. AFST with luliconazole and olorofim, here reported for the first time, displayed the highest in vitro activity, making these antifungals interesting alternative drugs but clinical studies are warranted for future therapeutic use.
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Affiliation(s)
- Bram Spruijtenburg
- Radboudumc-CWZ Center of Expertise for Mycology, Weg Door Jonkerbos 100, 6532 SZ, Nijmegen, The Netherlands
- Canisius-Wilhelmina Hospital (CWZ)/Dicoon, 6532 SZ, Nijmegen, The Netherlands
| | - Antonio Rezusta
- Servicio de Microbiología, Hospital Universitario Miguel Servet, IIS Aragon, Saragossa, Spain
| | - Jos Houbraken
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands
| | - Ferry Hagen
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands
- Institute for Biodiversity and Ecosystems Dynamics, University of Amsterdam, Amsterdam, The Netherlands
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Theun de Groot
- Radboudumc-CWZ Center of Expertise for Mycology, Weg Door Jonkerbos 100, 6532 SZ, Nijmegen, The Netherlands
- Canisius-Wilhelmina Hospital (CWZ)/Dicoon, 6532 SZ, Nijmegen, The Netherlands
| | - Jacques F Meis
- Radboudumc-CWZ Center of Expertise for Mycology, Weg Door Jonkerbos 100, 6532 SZ, 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
| | - Eelco F J Meijer
- Radboudumc-CWZ Center of Expertise for Mycology, Weg Door Jonkerbos 100, 6532 SZ, Nijmegen, The Netherlands.
- Canisius-Wilhelmina Hospital (CWZ)/Dicoon, 6532 SZ, Nijmegen, The Netherlands.
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Korkmaz E, Ergon MC. Investigation of antifungal susceptibility of Aspergillus species isolated from systemic clinical specimens by different methods. Indian J Med Microbiol 2024; 50:100642. [PMID: 38830536 DOI: 10.1016/j.ijmmb.2024.100642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 05/30/2024] [Accepted: 05/31/2024] [Indexed: 06/05/2024]
Abstract
PURPOSE Due to the potential for Aspergillus species to cause lethal infections and the rising rates of antifungal resistance, the significance of antifungal susceptibility tests has increased. We aimed to assess the sensitivities of Aspergillus species to amphotericin B (AMB), voriconazole (VOR), itraconazole (ITZ), and caspofungin (CAS) using disk diffusion (DD) and gradient diffusion (GD) methods and compare them with broth microdilution (BMD) as the reference susceptibility method. METHODS The study involved 62 Aspergillus fumigatus, 28 Aspergillus flavus, and 16 Aspergillus terreus isolates, totaling 106 Aspergillus isolates. BMD and DD methods were performed in accordance with CLSI M38-A2 and CLSI M51-A documents, respectively. The GD method utilized nonsupplemented Mueller Hinton agar (MHA) as the medium. RESULTS In the BMD method, the lowest minimal inhibitory concentration (MIC)90 or minimal effective concentration (MEC)90 values were observed for VOR and CAS (0.5 μg/mL and 0.06 μg/mL, respectively). AMB and ITZ MIC90 values were both 2 μg/mL. In our comparison of the GD method with the BMD method at ±2 dilution, we observed essential agreement rates of 91.6%, 99.1%, 100%, and 38.6% for AMB, VOR, ITZ, and CAS, respectively. When comparing DD and BMD methods, we found categorical agreement rates of 65.1%, 99.1%, 77.3%, and 100% for AMB, VOR, ITZ, and CAS, respectively. For GD and BMD methods, these rates were 79.2%, 99.1%, 87.8%, and 100%. CONCLUSIONS Given the high essential and categorical agreement rates, we posit that the GD method is a viable alternative to the BMD method for AMB, ITZ and VOR but not for CAS. In addition, the use of nonsupplemented MHA in the GD method proves advantageous due to its cost-effectiveness and widespread availability compared to other growth media.
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Affiliation(s)
- Emine Korkmaz
- Dokuz Eylül University Faculty of Medicine, Department of Medical Microbiology, İzmir, Turkey.
| | - M Cem Ergon
- Dokuz Eylül University Faculty of Medicine, Department of Medical Microbiology, İzmir, Turkey.
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Colombo SA, de Mello DMD, Morais BRM, Salvato LA, Dorella FA, Tavares GC, da Silva VMF, de Azevedo MI. CHARACTERIZATION OF THE FUNGAL MICROBIOTA IN THE NOSTRILS AND RECTUM OF AMAZONIAN MANATEES ( TRICHECHUS INUNGUIS) FROM A REHABILITATION PROGRAM IN BRAZIL. J Zoo Wildl Med 2024; 55:125-135. [PMID: 38453495 DOI: 10.1638/2022-0069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/14/2023] [Indexed: 03/09/2024] Open
Abstract
The present study characterized the filamentous and yeast-like fungal microbiota of the nasal cavity and rectum of Amazonian manatees (Trichechus inunguis) undergoing rehabilitation at the Laboratory of Aquatic Mammals, National Institute of Amazonian Research, Manaus, Amazonas, and determined the antifungal susceptibility of these organisms. Nasal and rectal swabs were collected from 22 calves and three juveniles. The samples were seeded in Sabouraud agar supplemented with chloramphenicol 10%, incubated at 26°C, and observed daily for up to 7 d. The growth of different filamentous and yeast-like fungi was observed among the two anatomical sites. Filamentous fungi were categorized by macro- and microscopic characteristics of the colonies. Representatives of each group were selected for molecular identification based on the internal transcribed spacer region. Yeast identification was performed using MALDI-TOF MS and molecular analyses. Thirteen genera of filamentous fungi and six genera of yeasts were isolated and identified. The dominant filamentous species were Fusarium spp., Aspergillus spp., and Cochliobolus lunatus in the nostril samples and Aspergillus melleus in the rectal samples. Candida was the dominant genus among the identified yeasts at both anatomical sites. In the antifungal susceptibility test, 28 isolates showed resistance to fluconazole (78%), itraconazole (39%), and nystatin (42%). The knowledge of fungal microbiota composition of Amazonian manatees provides information that assists in monitoring the health status of individuals maintained in captivity, as these organisms can behave either as opportunists or as primary pathogens. Moreover, the composition and resistance of these organisms may vary among different rehabilitation institutions or different time frames of search, reinforcing the importance of constant in loco surveillance of these microorganisms. This study provides new perspectives on the fungal diversity in the microbiota of manatees and supports future studies concerning the clinical and epidemiological aspects and the impacts of these agents on the health of Amazonian manatees undergoing rehabilitation.
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Affiliation(s)
- Salene A Colombo
- Department of Preventive Veterinary Medicine, School of Veterinary Medicine, Federal University of Minas Gerais, Belo Horizonte, MG 31270-901, Brazil
| | - Daniela M D de Mello
- Laboratory of Aquatic Mammals, National Institute of Amazonian Research-INPA, Manaus, AM 69060-001, Brazil
| | - Bruna R M Morais
- Department of Preventive Veterinary Medicine, School of Veterinary Medicine, Federal University of Minas Gerais, Belo Horizonte, MG 31270-901, Brazil
| | - Lauranne A Salvato
- Department of Preventive Veterinary Medicine, School of Veterinary Medicine, Federal University of Minas Gerais, Belo Horizonte, MG 31270-901, Brazil
| | - Fernanda A Dorella
- Department of Preventive Veterinary Medicine, School of Veterinary Medicine, Federal University of Minas Gerais, Belo Horizonte, MG 31270-901, Brazil
| | - Guilherme C Tavares
- Department of Preventive Veterinary Medicine, School of Veterinary Medicine, Federal University of Minas Gerais, Belo Horizonte, MG 31270-901, Brazil
| | - Vera M F da Silva
- Laboratory of Aquatic Mammals, National Institute of Amazonian Research-INPA, Manaus, AM 69060-001, Brazil
| | - Maria I de Azevedo
- Department of Preventive Veterinary Medicine, School of Veterinary Medicine, Federal University of Minas Gerais, Belo Horizonte, MG 31270-901, Brazil,
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Yerbanga IW, Nakanabo Diallo S, Rouamba T, Resendiz-Sharpe A, Lagrou K, Denis O, Rodriguez-Villalobos H, Montesinos I, Bamba S. Performances of disk diffusion method for determining triazole susceptibility of Aspergillus species: Systematic review. J Mycol Med 2023; 33:101413. [PMID: 37603962 DOI: 10.1016/j.mycmed.2023.101413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 07/05/2023] [Accepted: 07/11/2023] [Indexed: 08/23/2023]
Abstract
The therapeutic management of invasive aspergillosis should be guided by antifungal susceptibility testing (AFST). The disk diffusion (DD) method due to its simplicity and low cost could be an appropriate alternative to the reference methods (CLSI, EUCAST) which are not suitable for AFST in routine clinical microbiology laboratories, particularly in resource-constrained settings. This review summarizes the available data on the performance of the DD method in determining triazole susceptibility profile of Aspergillus species. The published articles on the performance of DD method for determining triazole susceptibility of Aspergillus spp. were systematically searched on major medical databases and Google Scholar. We identified 2725 articles of which 13 met the inclusion criteria. The overall average agreement value obtained between DD and CLSI broth microdilution (CLSI-BMD) methods for the itraconazole 10 µg disk (70.75%) was low especially when the medium used was not Mueller-Hinton (MH) agar. In contrast average agreement for the voriconazole 1 µg disk and the posaconazole 5 µg disk were > 94% regardless of media used. The correlation coefficient values between the DD and CLSI-BMD methods on MH agar were acceptable (≥ 0.71) for the itraconazole 10 µg disk and posaconazole 5 µg disk and good (≥ 0.80) for the voriconazole 1 and 10 µg disk. The reproducibility of the DD method regardless to the medium used was ≥ 82%. This systematic review shows that the disk diffusion method could be a real alternative for triazole antifungals susceptibility testing of Aspergillus spp.
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Affiliation(s)
- Isidore W Yerbanga
- Centre Hospitalier Universitaire Régional de Ouahigouya, 01 BP 36 Ouahigouya 01, Burkina Faso; Université Nazi Boni, 01 BP 1091 Bobo-Dioulasso 01, Burkina Faso.
| | - Seydou Nakanabo Diallo
- Université Nazi Boni, 01 BP 1091 Bobo-Dioulasso 01, Burkina Faso; Centre Muraz/Institut National de Santé Publique, 01 BP 390 Bobo-Dioulasso 01, Burkina Faso
| | - Toussaint Rouamba
- Clinical Research Unit of Nanoro, Institute for Research in Health Sciences, National Center for Scientific and Technological Research, BP: 218 Ouaga 11, Ouagadougou, Burkina Faso
| | | | - Katrien Lagrou
- Department of Microbiology, Immunology and Transplantation, KU Leuven, Leuven, Belgium; Department of Laboratory Medicine and National Reference Center for Mycosis, Excellence Center for Medical Mycology (ECMM), University Hospitals Leuven, Leuven, Belgium
| | - Olivier Denis
- Department of Microbiology, CHU Namur site-Godinne, Université Catholique de Louvain, Rue Dr Gaston Therasse 1, 5530 Yvoir, Belgium; Ecole de Santé Publique, Université Libre de Bruxelles, Brussels, Belgium
| | - Hector Rodriguez-Villalobos
- Department of Microbiology, Cliniques Universitaires Saint-Luc - Université Catholique de Louvain, Avenue Hippocrate 10, 1200 Bruxelles, Belgium
| | - Isabel Montesinos
- Department of Microbiology, CHU Namur site-Godinne, Université Catholique de Louvain, Rue Dr Gaston Therasse 1, 5530 Yvoir, Belgium
| | - Sanata Bamba
- Université Nazi Boni, 01 BP 1091 Bobo-Dioulasso 01, Burkina Faso; Centre Hospitalier Universitaire Sourô Sanou, 01 BP 676 Bobo-Dioulasso 01, Burkina Faso
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Durand C, Maubon D, Cornet M, Wang Y, Aldebert D, Garnaud C. Can We Improve Antifungal Susceptibility Testing? Front Cell Infect Microbiol 2021; 11:720609. [PMID: 34568095 PMCID: PMC8461061 DOI: 10.3389/fcimb.2021.720609] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 08/23/2021] [Indexed: 11/24/2022] Open
Abstract
Systemic antifungal agents are increasingly used for prevention or treatment of invasive fungal infections, whose prognosis remains poor. At the same time, emergence of resistant or even multi-resistant strains is of concern as the antifungal arsenal is limited. Antifungal susceptibility testing (AFST) is therefore of key importance for patient management and antifungal stewardship. Current AFST methods, including reference and commercial types, are based on growth inhibition in the presence of an antifungal, in liquid or solid media. They usually enable Minimal Inhibitory Concentrations (MIC) to be determined with direct clinical application. However, they are limited by a high turnaround time (TAT). Several innovative methods are currently under development to improve AFST. Techniques based on MALDI-TOF are promising with short TAT, but still need extensive clinical validation. Flow cytometry and computed imaging techniques detecting cellular responses to antifungal stress other than growth inhibition are also of interest. Finally, molecular detection of mutations associated with antifungal resistance is an intriguing alternative to standard AFST, already used in routine microbiology labs for detection of azole resistance in Aspergillus and even directly from samples. It is still restricted to known mutations. The development of Next Generation Sequencing (NGS) and whole-genome approaches may overcome this limitation in the near future. While promising approaches are under development, they are not perfect and the ideal AFST technique (user-friendly, reproducible, low-cost, fast and accurate) still needs to be set up routinely in clinical laboratories.
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Affiliation(s)
| | - Danièle Maubon
- TIMC, Univ Grenoble Alpes, CNRS, Grenoble INP, Grenoble, France.,Parasitology-Mycology, CHU Grenoble Alpes, Grenoble, France
| | - Muriel Cornet
- TIMC, Univ Grenoble Alpes, CNRS, Grenoble INP, Grenoble, France.,Parasitology-Mycology, CHU Grenoble Alpes, Grenoble, France
| | | | | | - Cécile Garnaud
- TIMC, Univ Grenoble Alpes, CNRS, Grenoble INP, Grenoble, France.,Parasitology-Mycology, CHU Grenoble Alpes, Grenoble, France
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Abstract
Although not as ubiquitous as antibacterial susceptibility testing, antifungal susceptibility testing (AFST) is a tool of increasing importance in clinical microbiology laboratories. The goal of AFST is to reliably produce MIC values that may be used to guide patient therapy, inform epidemiological studies, and track rates of antifungal drug resistance. There are three methods that have been standardized by standards development organizations: broth dilution, disk diffusion, and azole agar screening for Aspergillus Other commonly used methods include gradient diffusion and the use of rapid automated instruments. Novel methodologies for susceptibility testing are in development. It is important for laboratories to consider not only the method of testing but also the interpretation (or lack thereof) of in vitro data.
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Dannaoui E, Espinel-Ingroff A. Antifungal Susceptibly Testing by Concentration Gradient Strip Etest Method for Fungal Isolates: A Review. J Fungi (Basel) 2019; 5:jof5040108. [PMID: 31766762 PMCID: PMC6958406 DOI: 10.3390/jof5040108] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 11/13/2019] [Accepted: 11/16/2019] [Indexed: 12/23/2022] Open
Abstract
Antifungal susceptibility testing is an important tool for managing patients with invasive fungal infections, as well as for epidemiological surveillance of emerging resistance. For routine testing in clinical microbiology laboratories, ready-to-use commercial methods are more practical than homemade reference techniques. Among commercially available methods, the concentration gradient Etest strip technique is widely used. It combines an agar-based diffusion method with a dilution method that determinates a minimal inhibitory concentration (MIC) in µg/mL. Many studies have evaluated the agreement between the gradient strip method and the reference methods for both yeasts and filamentous fungi. This agreement has been variable depending on the antifungal, the species, and the incubation time. It has also been shown that the gradient strip method could be a valuable alternative for detection of emerging resistance (non-wild-type isolates) as Etest epidemiological cutoff values have been recently defined for several drug-species combinations. Furthermore, the Etest could be useful for direct antifungal susceptibility testing on blood samples and basic research studies (e.g., the evaluation of the in vitro activity of antifungal combinations). This review summarizes the available data on the performance and potential use of the gradient strip method.
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Affiliation(s)
- Eric Dannaoui
- Paris-Descartes University, Faculty of Medicine, 75006 Paris, France
- APHP, European Georges Pompidou Hospital, Parasitology-Mycology Unit, Microbiology Department, 75015 Paris, France
- Correspondence: ; Tel.: +33-15-6093-948; Fax: +33-15-6092-446
| | - Ana Espinel-Ingroff
- Virginia Commonwealth University (VCU) Medical Center, Richmond, VA 23219, USA;
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Arendrup MC, Verweij PE, Mouton JW, Lagrou K, Meletiadis J. Multicentre validation of 4-well azole agar plates as a screening method for detection of clinically relevant azole-resistant Aspergillus fumigatus. J Antimicrob Chemother 2018; 72:3325-3333. [PMID: 29029256 DOI: 10.1093/jac/dkx319] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 07/31/2017] [Indexed: 01/02/2023] Open
Abstract
Objectives Azole-resistant Aspergillus fumigatus is emerging worldwide. Reference susceptibility testing methods are technically demanding and no validated commercial susceptibility tests for moulds currently exist. In this multicentre study a 4-well azole-containing screening agar method was evaluated using clinically relevant isolates. Methods Forty WT and 39 cyp51A mutant A. fumigatus [G54 (n = 10), M220 (n = 10), TR34/L98H (n = 9) and TR46/Y121F/T289A (n = 10)] were tested individually and as simulated mixed samples (sampling 4 WT and 1 mutant colonies). EUCAST MICs were determined following E.Def 9.3. In-house and commercial 4-well plates containing agars supplemented with 4 mg/L itraconazole, 1 mg/L voriconazole, 0.5 mg/L posaconazole and no antifungal, respectively, were evaluated. Growth was scored (0-3) by two independent observers in three laboratories. Inter-plate, inter-observer, essential and categorical agreement, sensitivity and specificity were calculated. Results CYP51A genotype and antifungal compound-specific MICs and growth patterns were documented. The inter-observer agreement was excellent with 86%-99% identical scores (range 80%-100%) for both plates. The qualitative agreement (no growth versus growth) was excellent (median 95%-100%, range 87%-100%, overall). The overall sensitivity and specificity for the 4-well plate (no growth versus growth) was 99% (range 97%-100%) and 99% (95%-100%), respectively. The sensitivity for simulated WT/mutant specimens was 94% (range 83%-100%) for the WT-TR34/L98H combination, but 100% for the WT/G54W combination. The performance remained unchanged using only itraconazole- and voriconazole-containing agars, but was lower for the other combinations. Conclusions Implementation of the 4-well screening plate in routine laboratories will allow easy and reliable detection of the most common azole-resistant A. fumigatus.
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Affiliation(s)
- Maiken Cavling Arendrup
- Unit of Mycology, Statens Serum Institut, Copenhagen, Denmark.,Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Paul E Verweij
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, The Netherlands.,Centre of Expertise in Mycology, Radboudumc/CWZ, Nijmegen, The Netherlands
| | - Johan W Mouton
- Department of Medical Microbiology and Infectious Diseases, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Katrien Lagrou
- National Reference Center for Mycosis, University Hospitals Leuven, Leuven, Belgium.,Department of Microbiology and Immunology, University of Leuven, Leuven, Belgium
| | - Joseph Meletiadis
- Department of Medical Microbiology and Infectious Diseases, Erasmus Medical Center, Rotterdam, The Netherlands.,Clinical Microbiology Laboratory, Attikon University Hospital, National and Kapodistrian University of Athens, Athens, Greece
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Idelevich EA, Groß U, Becker K, Bader O. Comparative evaluation of different gradient diffusion tests for detection of azole resistance in Aspergillus fumigatus. Diagn Microbiol Infect Dis 2018; 91:52-54. [PMID: 29422272 DOI: 10.1016/j.diagmicrobio.2018.01.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 01/01/2018] [Accepted: 01/03/2018] [Indexed: 10/18/2022]
Abstract
Gradient diffusion assays Etest and MIC Test Strip for itraconazole, posaconazole and voriconazole as well as isavuconazole (MIC Test Strip) were evaluated for Aspergillus fumigatus against EUCAST broth microdilution. Both assays demonstrated generally good performance; however, posaconazole MIC Test Strip showed low agreement with broth microdilution due to MIC overestimation.
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Affiliation(s)
- Evgeny A Idelevich
- Institute of Medical Microbiology, University Hospital Münster, Domagkstraße 10, 48149 Münster, Germany
| | - Uwe Groß
- Institute for Medical Microbiology, University Medical Center Göttingen, Kreuzbergring 57, 37075 Göttingen, Germany
| | - Karsten Becker
- Institute of Medical Microbiology, University Hospital Münster, Domagkstraße 10, 48149 Münster, Germany.
| | - Oliver Bader
- Institute for Medical Microbiology, University Medical Center Göttingen, Kreuzbergring 57, 37075 Göttingen, Germany
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Heo MS, Shin JH, Choi MJ, Park YJ, Lee HS, Koo SH, Lee WG, Kim SH, Shin MG, Suh SP, Ryang DW. Molecular identification and amphotericin B susceptibility testing of clinical isolates of Aspergillus from 11 hospitals in Korea. Ann Lab Med 2016; 35:602-10. [PMID: 26354348 PMCID: PMC4579104 DOI: 10.3343/alm.2015.35.6.602] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Revised: 04/12/2015] [Accepted: 07/06/2015] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND We investigated the species distribution and amphotericin B (AMB) susceptibility of Korean clinical Aspergillus isolates by using two Etests and the CLSI broth microdilution method. METHODS A total of 136 Aspergillus isolates obtained from 11 university hospitals were identified by sequencing the internal transcribed spacer (ITS) and β-tubulin genomic regions. Minimal inhibitory concentrations (MICs) of AMB were determined in Etests using Mueller-Hinton agar (Etest-MH) and RPMI agar (Etest-RPG), and categorical agreement with the CLSI method was assessed by using epidemiological cutoff values. RESULTS ITS sequencing identified the following six Aspergillus species complexes: Aspergillus fumigatus (42.6% of the isolates), A. niger (23.5%), A. flavus (17.6%), A. terreus (11.0%), A. versicolor (4.4%), and A. ustus (0.7%). Cryptic species identifiable by β-tubulin sequencing accounted for 25.7% (35/136) of the isolates. Of all 136 isolates, 36 (26.5%) had AMB MICs of ≥2 μg/mL by the CLSI method. The categorical agreement of Etest-RPG with the CLSI method was 98% for the A. fumigatus, A. niger, and A. versicolor complexes, 87% for the A. terreus complex, and 37.5% for the A. flavus complex. That of Etest-MH was ≤75% for the A. niger, A. flavus, A. terreus, and A. versicolor complexes but was higher for the A. fumigatus complex (98.3%). CONCLUSIONS Aspergillus species other than A. fumigatus constitute about 60% of clinical Aspergillus isolates, and reduced AMB susceptibility is common among clinical isolates of Aspergillus in Korea. Molecular identification and AMB susceptibility testing by Etest-RPG may be useful for characterizing Aspergillus isolates of clinical relevance.
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Affiliation(s)
- Min Seok Heo
- Department of Laboratory Medicine, Chonnam National University Medical School, Gwangju, Korea
| | - Jong Hee Shin
- Department of Laboratory Medicine, Chonnam National University Medical School, Gwangju, Korea.
| | - Min Ji Choi
- Department of Laboratory Medicine, Chonnam National University Medical School, Gwangju, Korea
| | - Yeon Joon Park
- Department of Laboratory Medicine, The Catholic University of Korea College of Medicine, Seoul, Korea
| | - Hye Soo Lee
- Department of Laboratory Medicine, Chonbuk National University Medical School and Chonbuk National University Hospital Branch of National Culture Collection for Pathogens, Jeonju, Korea
| | - Sun Hoe Koo
- Department of Laboratory Medicine, College of Medicine, Chungnam National University, Gwangju, Korea
| | - Won Gil Lee
- Department of Laboratory Medicine, Kyungpook National University School of Medicine, Daegu, Korea
| | - Soo Hyun Kim
- Department of Laboratory Medicine, Chonnam National University Medical School, Gwangju, Korea
| | - Myung Geun Shin
- Department of Laboratory Medicine, Chonnam National University Medical School, Gwangju, Korea
| | - Soon Pal Suh
- Department of Laboratory Medicine, Chonnam National University Medical School, Gwangju, Korea
| | - Dong Wook Ryang
- Department of Laboratory Medicine, Chonnam National University Medical School, Gwangju, Korea
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Al-Wathiqi F, Ahmad S, Khan Z. Molecular identification and antifungal susceptibility profile of Aspergillus flavus isolates recovered from clinical specimens in Kuwait. BMC Infect Dis 2013; 13:126. [PMID: 23496810 PMCID: PMC3599693 DOI: 10.1186/1471-2334-13-126] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Accepted: 02/26/2013] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Within the genus Aspergillus, A. flavus is the second most important species of clinical significance. It is predominantly associated with infections involving sinuses, eye and skin, mostly in geographic regions with hot and arid climate, including the Middle East. Recent reports on emergence of resistance to triazoles among Aspergillus spp. is a cause of concern for treatment of patients with invasive aspergillosis. In this study we present data on genetic characterization and antifungal susceptibility profile of clinical and environmental isolates of A. flavus. METHODS Ninety-nine Aspergillus section Flavi isolates, originating from clinical (n=92) and environmental (n=7) sources, initially identified by morphological characteristics, were analyzed by partial sequencing of β-tubulin and calmodulin gene fragments and their susceptibilities to six antifungal agents was determined by Etest on RPMI1640 and Muller-Hinton agar media. Etest minimum inhibitory concentrations (MICs) of amphotericin B and voriconazole were also compared with zone of inhibition diameters obtained by disc diffusion test on RPMI agar medium. RESULTS The identity of all clinical and environmental isolates was confirmed as A. flavus species by combined analysis of β-tubulin and calmodulin genes. The mean MIC90 (μg/ml) values on RPMI medium for amphotericin B, voriconazole, posaconazole, anidulafungin, micafungin and caspofungin were 3, 0.25, 0.25, 0.002, 0.002 and 0.032, respectively. No environmental isolate exhibited MIC value of >2 μg/ml for amphotericin B. For clinical isolates, the zone of inhibition diameters for amphotericin B and voriconazole ranged from 7-16 mm and 24-34 mm, respectively. Linear regression analysis between Etest MIC values and disk diffusion diameters revealed a significant inverse correlation with amphotericin B (p <0.001) and voriconazole (p<0.003). CONCLUSIONS The β-tubulin and calmodulin gene sequences confirmed that all 92 clinical isolates identified phenotypically belonged to A. flavus taxon, thus suggesting that the other species within Aspergillus section Flavi are of little clinical significance. Triazoles and echinocandins showed very good in vitro activity against the A. flavus, however, 10% clinical isolates showed MICs of >2 μg/ml for amphotericin B.
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Affiliation(s)
- Faten Al-Wathiqi
- Department of Microbiology, Faculty of Medicine, Kuwait University, P. O. Box 24923, 13110, Safat, Kuwait
| | - Suhail Ahmad
- Department of Microbiology, Faculty of Medicine, Kuwait University, P. O. Box 24923, 13110, Safat, Kuwait
| | - Ziauddin Khan
- Department of Microbiology, Faculty of Medicine, Kuwait University, P. O. Box 24923, 13110, Safat, Kuwait
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Lass-Flörl C. In vitro susceptibility testing in Aspergillus species: an update. Future Microbiol 2010; 5:789-99. [PMID: 20441550 DOI: 10.2217/fmb.10.34] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aspergillus species are the most common causes of invasive mold infections in immunocompromised patients. The introduction of new antifungal agents and recent reports of resistance emerging during treatment of Aspergillus infections have highlighted the need for in vitro susceptibility testing. Various testing procedures have been proposed, including macro- and micro-dilution, disk diffusion, Etest (AB Biodisk, Sweden) and other commercial tests. Although Aspergillus species are generally susceptible to various compounds, intrinsic and acquired resistance has been documented. Amphotericin B has limited activity against Aspergillus terreus and Aspergillus nidulans. Not surprisingly, continued use of azole-based drugs has the undesirable consequence of elevating the resistance of subsequent isolates from these patients. Several species in the Aspergillus fumigatus complex appear to be resistant to azoles; there is evidence of in vitro and in vivo correlation. Each in vitro susceptibility testing method has its own advantages and disadvantages. Etest is easy to perform and use on a daily basis, yet it is expensive. Disk diffusion is the most attractive alternative method to date, yet we lack sufficient data for aspergilli. The European Committee on Antimicrobial Susceptibility Testing (EUCAST) and the Clinical Laboratory Standard Institute (CLSI) have produced reproducible reference testing methods. This article reviews the available methods for antifungal susceptibility testing in Aspergillus spp. as well as the scant data regarding the clinical implications of in vitro testing.
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Affiliation(s)
- Cornelia Lass-Flörl
- Department of Hygiene, Microbiology & Social Medicine, Division of Hygiene & Clinical Microbiology, Innsbruck Medical University, Fritz Pregl Str 3, 6020 Innsbruck, Austria.
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