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Siopi M, Georgiou PC, Pournaras S, Meletiadis J. Optimization of the EUCAST reference broth microdilution method for echinocandin susceptibility testing of Aspergillus fumigatus. J Antimicrob Chemother 2023; 78:2830-2839. [PMID: 37811550 PMCID: PMC11259975 DOI: 10.1093/jac/dkad306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 09/14/2023] [Indexed: 10/10/2023] Open
Abstract
BACKGROUND Because of the high inoculum (105 cfu/mL) used in the EUCAST susceptibility testing of Aspergillus spp., determination of the minimal effective concentration (MEC) of echinocandins is challenging as the morphological differences are subtle. METHODS The MECs of 10 WT and 4 non-WT Aspergillus fumigatus isolates were determined with the EUCAST E.Def 9.4. Plates were inoculated with increasing inocula (102-105 cfu/mL) and after 24 and 48 h of incubation, MECs were determined macroscopically (magnifying mirror) and microscopically (inverted microscope) by two observers, spectrophotometrically (OD at 405 nm) and colorimetrically (absorbance at 450/630 nm after 2 h incubation with 400 mg/L XTT/6.25 μM menadione). The interobserver (between observers)/intermethod (compared with the microscopic method) essential agreement (EA, ±1 2-fold dilution) and categorical agreement (CA) were determined for each inoculum. RESULTS Echinocandin-induced microscopic hyphal alterations or macroscopic changes in turbidity were subtle with a 105 cfu/mL inoculum compared with the lower inocula of 103 and 102 cfu/mL, where more distinct changes in turbidity and formation of characteristic rosettes were obvious at the MEC after 48 h. A 105 cfu/mL inoculum resulted in wider MEC distributions (3-6 dilutions) and lower interobserver EA (69%), macroscopic-microscopic EA (26%) and CA (71%) compared with a 103 cfu/mL inoculum (2-3 dilutions, 100%, 100% and 100%, respectively). Spectrophotometric readings using a 103 cfu/mL inoculum showed good EA (57-93%) and excellent CA (86%-100%), while the XTT assay demonstrated excellent EA (93%) and CA (100%). CONCLUSIONS A 48 h incubation using a 103 cfu/mL inoculum improved echinocandin MEC determination for A. fumigatus with the EUCAST method, while the colorimetric assay could allow automation.
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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
| | - Panagiota-Christina Georgiou
- Clinical Microbiology Laboratory, “Attikon” University General Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Spyros Pournaras
- Clinical Microbiology Laboratory, “Attikon” University General Hospital, 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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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: 27] [Impact Index Per Article: 13.5] [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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Arastehfar A, Carvalho A, Houbraken J, Lombardi L, Garcia-Rubio R, Jenks J, Rivero-Menendez O, Aljohani R, Jacobsen I, Berman J, Osherov N, Hedayati M, Ilkit M, Armstrong-James D, Gabaldón T, Meletiadis J, Kostrzewa M, Pan W, Lass-Flörl C, Perlin D, Hoenigl M. Aspergillus fumigatus and aspergillosis: From basics to clinics. Stud Mycol 2021; 100:100115. [PMID: 34035866 PMCID: PMC8131930 DOI: 10.1016/j.simyco.2021.100115] [Citation(s) in RCA: 106] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The airborne fungus Aspergillus fumigatus poses a serious health threat to humans by causing numerous invasive infections and a notable mortality in humans, especially in immunocompromised patients. Mould-active azoles are the frontline therapeutics employed to treat aspergillosis. The global emergence of azole-resistant A. fumigatus isolates in clinic and environment, however, notoriously limits the therapeutic options of mould-active antifungals and potentially can be attributed to a mortality rate reaching up to 100 %. Although specific mutations in CYP 51A are the main cause of azole resistance, there is a new wave of azole-resistant isolates with wild-type CYP 51A genotype challenging the efficacy of the current diagnostic tools. Therefore, applications of whole-genome sequencing are increasingly gaining popularity to overcome such challenges. Prominent echinocandin tolerance, as well as liver and kidney toxicity posed by amphotericin B, necessitate a continuous quest for novel antifungal drugs to combat emerging azole-resistant A. fumigatus isolates. Animal models and the tools used for genetic engineering require further refinement to facilitate a better understanding about the resistance mechanisms, virulence, and immune reactions orchestrated against A. fumigatus. This review paper comprehensively discusses the current clinical challenges caused by A. fumigatus and provides insights on how to address them.
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Affiliation(s)
- A. Arastehfar
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, 07110, USA
| | - A. Carvalho
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B's - PT Government Associate Laboratory, Guimarães/Braga, Portugal
| | - J. Houbraken
- Westerdijk Fungal Biodiversity Institute, Utrecht, the Netherlands
| | - L. Lombardi
- UCD Conway Institute and School of Medicine, University College Dublin, Dublin 4, Ireland
| | - R. Garcia-Rubio
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, 07110, USA
| | - J.D. Jenks
- Department of Medicine, University of California San Diego, San Diego, CA, 92103, USA
- Clinical and Translational Fungal-Working Group, University of California San Diego, La Jolla, CA, 92093, USA
| | - O. Rivero-Menendez
- Medical Mycology Reference Laboratory, National Center for Microbiology, Instituto de Salud Carlos III, Madrid, 28222, Spain
| | - R. Aljohani
- Department of Infectious Diseases, Imperial College London, London, UK
| | - I.D. Jacobsen
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology—Hans Knöll Institute, Jena, Germany
- Institute for Microbiology, Friedrich Schiller University, Jena, Germany
| | - J. Berman
- Research Group Microbial Immunology, Leibniz Institute for Natural Product Research and Infection Biology—Hans Knöll Institute, Jena, Germany
| | - N. Osherov
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine Ramat-Aviv, Tel-Aviv, 69978, Israel
| | - M.T. Hedayati
- Invasive Fungi Research Center/Department of Medical Mycology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - M. Ilkit
- Division of Mycology, Department of Microbiology, Faculty of Medicine, Çukurova University, 01330, Adana, Turkey
| | | | - T. Gabaldón
- Life Sciences Programme, Supercomputing Center (BSC-CNS), Jordi Girona, Barcelona, 08034, Spain
- Mechanisms of Disease Programme, Institute for Research in Biomedicine (IRB), Barcelona, Spain
- ICREA, Pg. Lluís Companys 23, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, 08010, Barcelona, Spain
| | - J. Meletiadis
- Clinical Microbiology Laboratory, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | | | - W. Pan
- Medical Mycology, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, 200003, China
| | - C. Lass-Flörl
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - D.S. Perlin
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, 07110, USA
| | - M. Hoenigl
- Department of Medicine, University of California San Diego, San Diego, CA, 92103, USA
- Section of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Medical University of Graz, 8036, Graz, Austria
- Division of Infectious Diseases and Global Public Health, Department of Medicine, University of California San Diego, San Diego, CA 92093, USA
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Carvalho VSD, Gómez-Delgado L, Curto MÁ, Moreno MB, Pérez P, Ribas JC, Cortés JCG. Analysis and application of a suite of recombinant endo-β(1,3)-D-glucanases for studying fungal cell walls. Microb Cell Fact 2021; 20:126. [PMID: 34217291 PMCID: PMC8254974 DOI: 10.1186/s12934-021-01616-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 06/19/2021] [Indexed: 12/31/2022] Open
Abstract
Background The fungal cell wall is an essential and robust external structure that protects the cell from the environment. It is mainly composed of polysaccharides with different functions, some of which are necessary for cell integrity. Thus, the process of fractionation and analysis of cell wall polysaccharides is useful for studying the function and relevance of each polysaccharide, as well as for developing a variety of practical and commercial applications. This method can be used to study the mechanisms that regulate cell morphogenesis and integrity, giving rise to information that could be applied in the design of new antifungal drugs. Nonetheless, for this method to be reliable, the availability of trustworthy commercial recombinant cell wall degrading enzymes with non-contaminating activities is vital. Results Here we examined the efficiency and reproducibility of 12 recombinant endo-β(1,3)-d-glucanases for specifically degrading the cell wall β(1,3)-d-glucan by using a fast and reliable protocol of fractionation and analysis of the fission yeast cell wall. This protocol combines enzymatic and chemical degradation to fractionate the cell wall into the four main polymers: galactomannoproteins, α-glucan, β(1,3)-d-glucan and β(1,6)-d-glucan. We found that the GH16 endo-β(1,3)-d-glucanase PfLam16A from Pyrococcus furiosus was able to completely and reproducibly degrade β(1,3)-d-glucan without causing the release of other polymers. The cell wall degradation caused by PfLam16A was similar to that of Quantazyme, a recombinant endo-β(1,3)-d-glucanase no longer commercially available. Moreover, other recombinant β(1,3)-d-glucanases caused either incomplete or excessive degradation, suggesting deficient access to the substrate or release of other polysaccharides. Conclusions The discovery of a reliable and efficient recombinant endo-β(1,3)-d-glucanase, capable of replacing the previously mentioned enzyme, will be useful for carrying out studies requiring the digestion of the fungal cell wall β(1,3)-d-glucan. This new commercial endo-β(1,3)-d-glucanase will allow the study of the cell wall composition under different conditions, along the cell cycle, in response to environmental changes or in cell wall mutants. Furthermore, this enzyme will also be greatly valuable for other practical and commercial applications such as genome research, chromosomes extraction, cell transformation, protoplast formation, cell fusion, cell disruption, industrial processes and studies of new antifungals that specifically target cell wall synthesis. Supplementary Information The online version contains supplementary material available at 10.1186/s12934-021-01616-0.
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Affiliation(s)
- Vanessa S D Carvalho
- Instituto de Biología Funcional y Genómica Zacarías González, 2. CSIC and Universidad de Salamanca, 37007, Salamanca, Spain
| | - Laura Gómez-Delgado
- Instituto de Biología Funcional y Genómica Zacarías González, 2. CSIC and Universidad de Salamanca, 37007, Salamanca, Spain
| | - M Ángeles Curto
- Instituto de Biología Funcional y Genómica Zacarías González, 2. CSIC and Universidad de Salamanca, 37007, Salamanca, Spain
| | - M Belén Moreno
- Instituto de Biología Funcional y Genómica Zacarías González, 2. CSIC and Universidad de Salamanca, 37007, Salamanca, Spain
| | - Pilar Pérez
- Instituto de Biología Funcional y Genómica Zacarías González, 2. CSIC and Universidad de Salamanca, 37007, Salamanca, Spain
| | - Juan Carlos Ribas
- Instituto de Biología Funcional y Genómica Zacarías González, 2. CSIC and Universidad de Salamanca, 37007, Salamanca, Spain.
| | - Juan Carlos G Cortés
- Instituto de Biología Funcional y Genómica Zacarías González, 2. CSIC and Universidad de Salamanca, 37007, Salamanca, Spain.
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Meletiadis J, Siopi M, Kanioura L, Jørgensen KM, Perlin DS, Mouton JW, Arendrup MC. Development and multicentre validation of an agar-based screening method for echinocandin susceptibility testing of Aspergillus species. J Antimicrob Chemother 2020; 74:2247-2254. [PMID: 31106352 DOI: 10.1093/jac/dkz154] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 02/15/2019] [Accepted: 03/18/2019] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Reference antifungal susceptibility testing of echinocandins against Aspergillus spp. relies on the determination of the minimal effective concentration, which is difficult to perform, time-consuming and subjective. We developed and evaluated in a multicentre study an agar-based screening method for echinocandin susceptibility testing of Aspergillus spp. METHODS Forty WT isolates [10 Aspergillus fumigatus species complex (SC), 10 Aspergillus flavus SC, 10 Aspergillus terreus SC and 10 Aspergillus niger SC] and 4 non-WT A. fumigatus isolates with or without known fks alterations were used. The optimal test conditions and stability over time were evaluated in preliminary studies monitoring colony growth. Twenty-microlitre aliquots of 1-2 McFarland inocula in 0.1% Tween 20 aqueous solution were added to each well and plates were incubated for 24/48 h at 35 ± 2°C. Subsequently, all isolates were tested blindly at three centres using four-well screening plates, containing anidulafungin, caspofungin, micafungin or no antifungal in each of the four wells, respectively. RESULTS WT isolates produced fluffy colonies on drug-free agar wells only. The non-WT isolates produced fluffy colonies on echinocandin-containing and control agar wells. Using the echinocandin concentrations of 0.25 mg/L anidulafungin, 1 mg/L caspofungin and 0.125 mg/L micafungin, and the compact (non-fluffy) versus fluffy colony morphology endpoint, all centres successfully discriminated non-WT and WT strains even after 24 h. Among the three echinocandins, anidulafungin produced the clearest endpoints. CONCLUSIONS The four-well plate agar method is suitable for echinocandin susceptibility screening of Aspergillus spp. and can be used to detect echinocandin non-WT isolates.
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Affiliation(s)
- Joseph Meletiadis
- Clinical Microbiology Laboratory, Attikon University General Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece.,Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Maria Siopi
- Clinical Microbiology Laboratory, Attikon University General Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Lamprini Kanioura
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center, Rotterdam, The Netherlands
| | | | - David S Perlin
- Public Health Research Institute, New Jersey Medical School, Rutgers Biomedical and Health Sciences, Newark, NJ, USA
| | - Johan W Mouton
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - 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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In Vitro Activity of Manogepix (APX001A) and Comparators against Contemporary Molds: MEC Comparison and Preliminary Experience with Colorimetric MIC Determination. Antimicrob Agents Chemother 2020; 64:AAC.00730-20. [PMID: 32513793 DOI: 10.1128/aac.00730-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 06/02/2020] [Indexed: 12/26/2022] Open
Abstract
Manogepix (APX001A) is the active moiety of the drug candidate fosmanogepix (APX001), currently in clinical development for the treatment of invasive fungal infections. We compared manogepix EUCAST minimum effective concentrations (MECs) to MICs of five comparators and CLSI MECs and MICs by a colorimetric method against contemporary molds. EUCAST susceptibility testing was performed for 161 isolates. Interlaboratory and intermethod reproducibility were determined by comparison with published manogepix MECs. Colorimetric MICs (measuring metabolic activity) were evaluated using three Aspergillus fumigatus isolates and one Aspergillus flavus isolate with four inocula at 24 to 48 h of incubation and 1 to 3 h 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide salt (XTT)/menadione (MEN) exposure. Manogepix modal MECs (range in mg/liter) against Aspergillus species were 0.03 to 0.06 (0.008 to 0.125) and unaffected by itraconazole resistance. Manogepix was as active against two Fusarium isolates but inactive against Trichophyton interdigitale, Lichtheimia ramosa, and Rhizomucor pusillus isolates (MECs >0.5). Modal MEC/MICs were ≥3 2-fold dilutions apart without overlapping ranges comparing manogepix with amphotericin B, isavuconazole, and voriconazole against Aspergillus isolates. Manogepix and posaconazole MECs/MICs correlated for Aspergillus niger (Pearson's r = 0.711; P = 0.0044). The MEC at which 50% of the isolates tested are inhibited (MEC50), mode, and MEC90 values were within ±1 dilution in all cases compared with published EUCAST and CLSI data. The colorimetric method showed excellent agreement with the MECs when plates were inoculated with the lowest inoculum (1 × 102 CFU/ml to 2.5 × 102 CFU/ml), incubated for 24 h, and exposed for 1 to 3 h to XTT/MEN. Broad-spectrum in vitro activity of manogepix against clinically relevant molds was confirmed with excellent agreement across EUCAST and CLSI methods reported from experienced mycology laboratories. Colorimetric MIC determination warrants further investigation as a potential alternative that is less dependent on mycology expertise.
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FKS1 mutation associated with decreased echinocandin susceptibility of Aspergillus fumigatus following anidulafungin exposure. Sci Rep 2020; 10:11976. [PMID: 32686741 PMCID: PMC7371691 DOI: 10.1038/s41598-020-68706-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 06/03/2020] [Indexed: 11/28/2022] Open
Abstract
Invasive aspergillosis (IA) is a potentially lethal infection that affects mostly immunocompromised patients caused by Aspergillus fumigatus. Echinocandins are a second-line therapy against IA, used as a salvage therapy as well as for empirical or prophylactic therapy. Although they cause lysis of growing hyphal tips, they are considered fungistatic against molds. In vivo echinocandins resistance is uncommon; however, its wide clinical use could shortly lead to the emergence of A. fumigatus resistance. The aims of the present work was to assess the development of reduced echinocandins susceptibility phenotype by a A. fumigatus strain and to unveil the molecular mechanism underlying such phenotype. We induced in vitro cross-resistance to echinocandins following exposure of A. fumigatus to anidulafungin. Stability of the resistant phenotype was confirmed after removal of anidulafungin pressure. The FKS1 gene was partially sequenced and a E671Q mutation was found. A computational approach suggests that it can play an important role in echinocandin resistance. Given the emerging importance of this mechanism for clinical resistance in pathogenic fungi, it would be prudent to be alert to the potential evolution of this resistant mechanism in Aspergillus spp infecting patients under echinocandins therapeutics.
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Meletiadis J, Siopi M, Kanioura L, Jørgensen KM, Perlin DS, Mouton JW, Arendrup MC. A multicentre study to optimize echinocandin susceptibility testing of Aspergillus species with the EUCAST methodology and a broth microdilution colorimetric method. J Antimicrob Chemother 2020; 75:1799-1806. [PMID: 32330938 PMCID: PMC7303820 DOI: 10.1093/jac/dkaa102] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 02/20/2020] [Accepted: 02/26/2020] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND The determination of the minimal effective concentration (MEC) of echinocandins against Aspergillus species is subjective, time consuming and has been associated with very major errors. METHODS The MECs/MICs of 40 WT [10 each of Aspergillus fumigatus species complex (SC), Aspergillus flavus SC, Aspergillus terreus SC and Aspergillus niger SC] and 4 non-WT A. fumigatus isolates were determined with EUCAST E.Def 9.3.1 read microscopically, macroscopically, spectrophotometrically and colorimetrically in three centres. The optimal conditions for spectrophotometric (single- versus multi-point readings) and colorimetric (XTT/menadione concentration and stability, incubation time) methods were evaluated in preliminary studies using different cut-offs for the determination of macroscopic, spectrophotometric and colorimetric MIC endpoints compared with the microscopically determined MEC. Inter-centre and inter-method essential (within one 2-fold dilution) agreement (EA) and categorical agreement (CA) were determined. RESULTS Both macroscopic and spectrophotometric endpoint readings showed poor inter-centre EA (53%-66%) and low CA (41%-88%) in distinguishing WT from non-WT A. fumigatus SC isolates, while significant differences compared with the microscopic MECs were observed for all echinocandins (EA 6%-54%). For the colorimetric method, the optimal conditions were 400 mg/L XTT/6.25 μΜ menadione, incubation for 1-2 h until the drug-free control reached an absorbance at 450/630 nm of >0.8 and use of 50% inhibition of XTT conversion as a cut-off for all species and echinocandins. All non-WT isolates had high XTT MICs >1 mg/L, whereas the overall inter-centre EA and CA were 72%-89% and 100%, respectively. CONCLUSIONS The XTT colorimetric assay improved the antifungal susceptibility testing of echinocandins against Aspergillus spp., reliably detecting non-WT isolates.
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Affiliation(s)
- Joseph Meletiadis
- Clinical Microbiology Laboratory, Attikon University General Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Maria Siopi
- Clinical Microbiology Laboratory, Attikon University General Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Lamprini Kanioura
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center, Rotterdam, The Netherlands
| | | | - David S Perlin
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, USA
| | - Johan W Mouton
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - 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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Abstract
Fungal diseases, including those caused by (multi)drug-resistant fungi, still represent a global public health concern. Information on the susceptibility of these microorganisms to antifungal agents must be quickly produced to help clinicians initiate appropriate antifungal therapies. Unfortunately, antifungal susceptibility tests are not as developed or widely implemented as antibacterial tests, being similar in design, accuracy and reproducibility, but also laborious and slow. In this article, we review the methods of in vitro susceptibility testing, both reference (CLSI and EUCAST), commercial and new methods based on proteomics (MALDI-TOF MS) and in the detection of resistance genes by nucleic acid amplification techniques. In addi-tion, we discuss the newly established clinical breakpoints, as well as the epidemiological cut-off points, which constitute a new category that can help in the early identification of isolates that have acquired resistance mechanisms. We also discuss the advantages and limitations of each of the methods studied. Therefore, we can conclude that, although there has been much progress in studies of in vitro susceptibility testing to antifungals, there are still limitations in its application in the daily routine of microbiology labo-ratories, although it seems that the future is promising with the new technologies based on proteomics and nucleic acid amplification. Supplement information: This article is part of a supplement entitled «SEIMC External Quality Control Programme. Year 2016», which is sponsored by Roche, Vircell Microbiologists, Abbott Molecular and Francisco Soria Melguizo, S.A. © 2019 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosasy Microbiología Clínica. All rights reserved.
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Ruhnke M, Cornely OA, Schmidt-Hieber M, Alakel N, Boell B, Buchheidt D, Christopeit M, Hasenkamp J, Heinz WJ, Hentrich M, Karthaus M, Koldehoff M, Maschmeyer G, Panse J, Penack O, Schleicher J, Teschner D, Ullmann AJ, Vehreschild M, von Lilienfeld-Toal M, Weissinger F, Schwartz S. Treatment of invasive fungal diseases in cancer patients-Revised 2019 Recommendations of the Infectious Diseases Working Party (AGIHO) of the German Society of Hematology and Oncology (DGHO). Mycoses 2020; 63:653-682. [PMID: 32236989 DOI: 10.1111/myc.13082] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 03/05/2020] [Accepted: 03/10/2020] [Indexed: 12/15/2022]
Abstract
BACKGROUND Invasive fungal diseases remain a major cause of morbidity and mortality in cancer patients undergoing intensive cytotoxic therapy. The choice of the most appropriate antifungal treatment (AFT) depends on the fungal species suspected or identified, the patient's risk factors (eg length and depth of granulocytopenia) and the expected side effects. OBJECTIVES Since the last edition of recommendations for 'Treatment of invasive fungal infections in cancer patients' of the Infectious Diseases Working Party (AGIHO) of the German Society of Hematology and Medical Oncology (DGHO) in 2013, treatment strategies were gradually moving away from solely empirical therapy of presumed or possible invasive fungal diseases (IFDs) towards pre-emptive therapy of probable IFD. METHODS The guideline was prepared by German clinical experts for infections in cancer patients in a stepwise consensus process. MEDLINE was systematically searched for English-language publications from January 1975 up to September 2019 using the key terms such as 'invasive fungal infection' and/or 'invasive fungal disease' and at least one of the following: antifungal agents, cancer, haematological malignancy, antifungal therapy, neutropenia, granulocytopenia, mycoses, aspergillosis, candidosis and mucormycosis. RESULTS AFT of IFDs in cancer patients may include not only antifungal agents but also non-pharmacologic treatment. In addition, the armamentarium of antifungals for treatment of IFDs has been broadened (eg licensing of isavuconazole). Additional antifungals are currently under investigation or in clinical trials. CONCLUSIONS Here, updated recommendations for the treatment of proven or probable IFDs are given. All recommendations including the levels of evidence are summarised in tables to give the reader rapid access to key information.
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Affiliation(s)
- Markus Ruhnke
- Division of Haematology, Oncology and Palliative Care, Department of Internal Medicine, Evangelisches Klinikum Bethel, Bielefeld, Germany
| | - Oliver A Cornely
- Department I of Internal Medicine, Faculty of Medicine, University of Cologne, Cologne, Germany.,ECMM Excellence Centre of Medical Mycology, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Clinical Trials Centre Cologne (ZKS Köln), University of Cologne, Cologne, Germany
| | | | - Nael Alakel
- Department I of Internal Medicine, Haematology and Oncology, University Hospital Dresden, Dresden, Germany
| | - Boris Boell
- Department I of Internal Medicine, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Dieter Buchheidt
- Department of Hematology and Oncology, Mannheim University Hospital, Heidelberg University, Mannheim, Germany
| | - Maximilian Christopeit
- Department of Stem Cell Transplantation & Oncology, University Medical Center Eppendorf, Hamburg, Germany
| | - Justin Hasenkamp
- Clinic for Haematology and Medical Oncology with Department for Stem Cell Transplantation, University Medicine Göttingen, Göttingen, Germany
| | - Werner J Heinz
- Schwerpunkt Infektiologie, Medizinische Klinik und Poliklinik II, Universitätsklinikum Würzburg, Würzburg, Germany
| | - Marcus Hentrich
- Hämatologie und Internistische Onkologie, Innere Medizin III, Rotkreuzklinikum München, München, Germany
| | - Meinolf Karthaus
- Department of Haematology & Oncology, Municipal Hospital Neuperlach, München, Germany
| | - Michael Koldehoff
- Klinik für Knochenmarktransplantation, Westdeutsches Tumorzentrum Essen, Universitätsklinikum Essen (AöR), Essen, Germany
| | - Georg Maschmeyer
- Department of Hematology, Onclogy and Palliative Care, Klinikum Ernst von Bergmann, Potsdam, Germany
| | - Jens Panse
- Klinik für Onkologie, Hämatologie und Stammzelltransplantation, Universitätsklinikum Aachen, Aachen, Germany
| | - Olaf Penack
- Division of Haematology & Oncology, Department of Internal Medicine, Charité University Medicine, Campus Rudolf Virchow, Berlin, Germany
| | - Jan Schleicher
- Klinik für Hämatologie Onkologie und Palliativmedizin, Katharinenhospital, Stuttgart, Germany
| | - Daniel Teschner
- III. Medizinische Klinik und Poliklinik, Universitätsmedizin der Johannes Gutenberg-Universität Mainz, Mainz, Germany
| | - Andrew John Ullmann
- Department of Internal Medicine II, Julius Maximilians University, Würzburg, Germany
| | - Maria Vehreschild
- Department I of Internal Medicine, Faculty of Medicine, University of Cologne, Cologne, Germany.,ECMM Excellence Centre of Medical Mycology, Cologne, Germany.,Zentrum für Innere Medizin, Infektiologie, Goethe Universität Frankfurt, Frankfurt am Main, Deutschland.,Deutsches Zentrum für Infektionsforschung (DZIF), Standort Bonn-Köln, Deutschland
| | - Marie von Lilienfeld-Toal
- Klinik für Innere Medizin II, Abteilung für Hämatologie und Internistische Onkologie, Universitätsklinikum Jena, Jena, Germany
| | - Florian Weissinger
- Division of Haematology, Oncology and Palliative Care, Department of Internal Medicine, Evangelisches Klinikum Bethel, Bielefeld, Germany
| | - Stefan Schwartz
- Division of Haematology & Oncology, Department of Internal Medicine, Charité University Medicine, Campus Benjamin Franklin, Berlin, Germany
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11
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Detection of Echinocandin-Resistant Candida glabrata in Blood Cultures Spiked with Different Percentages of FKS2 Mutants. Antimicrob Agents Chemother 2019; 63:AAC.02004-18. [PMID: 30559139 DOI: 10.1128/aac.02004-18] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 12/13/2018] [Indexed: 02/06/2023] Open
Abstract
Infections caused by the coexistence of Candida glabrata echinocandin-resistant and echinocandin-susceptible cells may be possible, and the detection of FKS mutants when the proportions of FKS mutants are underrepresented poses a problem. We assessed the role of EUCAST and methods directly performed on positive blood cultures-Etest (ETDIR) and anidulafungin-containing agar plate assays-for detecting resistance in C. glabrata isolates containing different amounts of echinocandin-susceptible and -resistant Candida glabrata isolates. We studied 10 pairs of C. glabrata isolates involving parental echinocandin-susceptible isolates and isogenic echinocandin-resistant FKS mutant isolates. Three inocula per pair (1 × 103 to 5 × 103, 1 × 102 to 5 × 102, and 10 to 50 CFU/ml) spanning suspensions with different amounts of susceptible/resistant isolates (9/1, 5/5, and 1/9 proportions for each the three inocula) were prepared. The suspensions were spiked in Bactec bottles and incubated until they were positive, and the three methods were compared. The EUCAST method showed echinocandin resistance when the bottles were spiked with susceptible/resistant isolates at 5/5 and 1/9 proportions; the results for the suspensions with a 9/1 proportion of susceptible/resistant isolates were susceptible for three pairs. We observed with the ETDIR resistance to both echinocandins in all pairs (resistance to micafungin and anidulafungin; MICs, ≥0.064 mg/liter and ≥0.125 mg/liter, respectively) and a double ring of growth inhibition in two pairs. The anidulafungin-containing plates showed fungal growth in the 90 spiked blood cultures at 48 h. Testing of echinocandin susceptibility with the ETDIR directly on the positive blood culture bottles is a reliable and rapid method to detect echinocandin resistance in C. glabrata On the other hand, resistance can be missed with the EUCAST method when resistant isolates are underrepresented.
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12
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Desoubeaux G, Cray C. Animal Models of Aspergillosis. Comp Med 2018; 68:109-123. [PMID: 29663936 PMCID: PMC5897967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 03/29/2017] [Accepted: 07/09/2017] [Indexed: 06/08/2023]
Abstract
Aspergillosis is an airborne fungal disease caused by Aspergillus spp., a group of ubiquitous molds. This disease causes high morbidity and mortality in both humans and animals. The growing importance of this infection over recent decades has created a need for practical and reproducible models of aspergillosis. The use of laboratory animals provides a platform to understand fungal virulence and pathophysiology, assess diagnostic tools, and evaluate new antifungal drugs. In this review, we describe the fungus, various Aspergillus-related diseases in humans and animals and various experimental animal models. Overall, we highlight the advantages and limitations of the animal models, the experimental variables that can affect the course of the disease and the reproducibility of infection, and the critical need for standardization of the species, immunosuppressive drugs, route of infection, and diagnostic criteria to use.
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Affiliation(s)
- Guillaume Desoubeaux
- Department of Pathology and Laboratory Medicine, Division of Comparative Pathology, Miller School of Medicine, University of Miami, Miami, Florida, USA; Parasitology-Mycology Service, Tropical Medicine Program, University Hospital of Tours, CEPR - Inserm U1100, Medical Faculty, François Rabelais University, Tours, France
| | - Carolyn Cray
- Department of Pathology and Laboratory Medicine, Division of Comparative Pathology, Miller School of Medicine, University of Miami, Miami, Florida, USA.,
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13
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Sharma C, Chowdhary A. Molecular bases of antifungal resistance in filamentous fungi. Int J Antimicrob Agents 2017; 50:607-616. [DOI: 10.1016/j.ijantimicag.2017.06.018] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2016] [Revised: 06/16/2017] [Accepted: 06/24/2017] [Indexed: 01/15/2023]
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14
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Lewis RE, Verweij PE. Animal Models for Studying Triazole Resistance in Aspergillus fumigatus. J Infect Dis 2017; 216:S466-S473. [PMID: 28911046 DOI: 10.1093/infdis/jix222] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Infections caused by triazole-resistant Aspergillus fumigatus are associated with a higher probability of treatment failure and mortality. Because clinical experience in managing these infections is still limited, mouse models of invasive aspergillosis fulfill a critical void for studying treatment regimens designed to overcome resistance. The type of immunosuppression, the route of infection, the timing of antifungal administration, and the end points used to assess antifungal activity affect the interpretation of data from these models. Nevertheless, these models provide important insights that help guide treatment decisions in patients with triazole-resistant invasive aspergillosis. Animal models confirmed that a high triazole minimal inhibitory concentration corresponded with triazole treatment failure and that the efficacy of other classes of drugs, such as the polyenes and echinocandins, was not affected by the presence of triazole resistance mutations. Furthermore, the feasibility of triazole dose escalation, combination therapy, and prophylaxis were explored as strategies to overcome resistance.
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Affiliation(s)
- Russell E Lewis
- Infectious Diseases Unit, S. Orsola-Malpighi Hospital, Department of Medical and Surgical Sciences, University of Bologna, Italy
| | - Paul E Verweij
- Department of Medical Microbiology, Radboud University Medical Center.,Center of Expertise in Mycology Radboudumc/CWZ, Nijmegen, the Netherlands
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15
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Patil A, Majumdar S. Echinocandins in antifungal pharmacotherapy. J Pharm Pharmacol 2017; 69:1635-1660. [DOI: 10.1111/jphp.12780] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 06/05/2017] [Indexed: 12/12/2022]
Abstract
Abstract
Objectives
Echinocandins are the newest addition of the last decade to the antifungal armamentarium, which, owing to their unique mechanism of action, selectively target the fungal cells without affecting mammalian cells. Since the time of their introduction, they have come to occupy an important niche in the antifungal pharmacotherapy, due to their efficacy, safety, tolerability and favourable pharmacokinetic profiles. This review deals with the varying facets of echinocandins such as their chemistry, in-vitro and in-vivo evaluations, clinical utility and indications, pharmacokinetic and pharmacodynamic profiles, and pharmacoeconomic considerations.
Key findings
Clinical studies have demonstrated that the echinocandins – caspofungin, micafungin and anidulafungin – are equivalent, if not superior, to the mainstay antifungal therapies involving amphotericin B and fluconazole. Moreover, echinocandin regimen has been shown to be more cost-effective and economical. Hence, the echinocandins have found favour in the management of invasive systemic fungal infections.
Conclusions
The subtle differences in echinocandins with respect to their pharmacology, clinical therapy and the mechanisms of resistance are emerging at a rapid pace from the current pool of research which could potentially aid in extending their utility in the fungal infections of the eye, heart and nervous system.
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Affiliation(s)
- Akash Patil
- Department of Pharmaceutics and Drug Delivery, School of Pharmacy, University of Mississippi, Oxford, MS, USA
| | - Soumyajit Majumdar
- Department of Pharmaceutics and Drug Delivery, School of Pharmacy, University of Mississippi, Oxford, MS, USA
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16
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Siopi M, Pournaras S, Meletiadis J. Comparative Evaluation of Sensititre YeastOne and CLSI M38-A2 Reference Method for Antifungal Susceptibility Testing of Aspergillus spp. against Echinocandins. J Clin Microbiol 2017; 55:1714-1719. [PMID: 28330883 PMCID: PMC5442527 DOI: 10.1128/jcm.00044-17] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2017] [Accepted: 03/14/2017] [Indexed: 01/06/2023] Open
Abstract
Sensititre YeastOne (YO) panels were assessed for in vitro susceptibility testing of echinocandins against 39 isolates of Aspergillus fumigatus, A. flavus, and A. terreus, including two echinocandin-resistant A. fumigatus strains, using different inocula (103, 104, and 105 CFU/ml), incubation times (16 to 48 h), and endpoints (first blue or purple well) and compared to CLSI M38-A2. The best agreement was found with an inoculum of 104 CFU/ml, incubation times of 20 h for A. flavus and of 30 h for A. fumigatus and A. terreus, and reading the first purple well. The reproducibility within ±1 2-fold dilutions was 100% for all three echinocandins. YO color endpoints were 2 to 3 2-fold dilutions lower than CLSI minimum effective concentrations (MECs) of caspofungin and 1 to 2 2-fold dilutions higher than CLSI MECs of micafungin. For anidulafungin, off-scale YO color endpoints were observed. Nevertheless, A. fumigatus echinocandin-resistant isolates were detected after 24 h of incubation.
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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
| | - Spyros Pournaras
- Clinical Microbiology Laboratory, Attikon University General Hospital, 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
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, Rotterdam, The Netherlands
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17
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Al-Hatmi AMS, Curfs-Breuker I, de Hoog GS, Meis JF, Verweij PE. Antifungal Susceptibility Testing of Fusarium: A Practical Approach. J Fungi (Basel) 2017; 3:jof3020019. [PMID: 29371537 PMCID: PMC5715922 DOI: 10.3390/jof3020019] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Revised: 04/14/2017] [Accepted: 04/19/2017] [Indexed: 12/12/2022] Open
Abstract
In vitro susceptibility testing of Fusarium is becoming increasingly important because of frequency and diversity of infections and because resistance profiles are species-specific. Reference methods for antifungal susceptibility testing (AFST) are those of Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility (EUCAST), but breakpoints (BPs) have not yet been established. One of the problems is that phylogenetic distances between Fusarium species are much smaller than between species of, e.g., Candida. Epidemiological cutoff values (ECVs) for some Fusarium species have been determined in order to differentiate wild-type from non-wild-type isolates. In clinical routine, commercially available assays such as Etest, Sensititre or others provide essential agreement with reference methods. Our objective is to summarize antifungal susceptibility testing of Fusarium genus in the clinical laboratory: how to do it, when to do it, and how to interpret it.
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Affiliation(s)
- Abdullah M S Al-Hatmi
- Westerdijk Fungal Biodiversity Institute, PO Box 85167, 3508 AD Utrecht, The Netherlands.
- Centre of Expertise in Mycology Radboud University Medical Centre, Canisius Wilhelmina Hospital, 6500HB Nijmegen, The Netherlands.
- Ministry of Health, Directorate General of Health Services, PO Box 393, 100 Muscat, Oman.
| | - Ilse Curfs-Breuker
- Department of Medical Microbiology and Infectious Diseases, Canisius Wilhelmina Hospital, 6500HB Nijmegen, The Netherlands.
| | - G Sybren de Hoog
- Westerdijk Fungal Biodiversity Institute, PO Box 85167, 3508 AD Utrecht, The Netherlands.
- Basic Pathology Department, Federal University of Paraná State, Curitiba, 81540-970 Paraná, Brazil.
- Biological Sciences Department, Faculty of Science, King Abdulaziz University, PO Box 80203 Jeddah, Saudi Arabia.
| | - Jacques F Meis
- Centre of Expertise in Mycology Radboud University Medical Centre, Canisius Wilhelmina Hospital, 6500HB Nijmegen, The Netherlands.
- Department of Medical Microbiology and Infectious Diseases, Canisius Wilhelmina Hospital, 6500HB Nijmegen, The Netherlands.
| | - Paul E Verweij
- Centre of Expertise in Mycology Radboud University Medical Centre, Canisius Wilhelmina Hospital, 6500HB Nijmegen, The Netherlands.
- Department of Medical Microbiology, Radboud University, Nijmegen Medical Centre, 6500GS Nijmegen, The Netherlands.
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18
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Gonçalves SS, Souza ACR, Chowdhary A, Meis JF, Colombo AL. Epidemiology and molecular mechanisms of antifungal resistance in CandidaandAspergillus. Mycoses 2016; 59:198-219. [DOI: 10.1111/myc.12469] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Revised: 12/14/2015] [Accepted: 12/18/2015] [Indexed: 12/15/2022]
Affiliation(s)
- Sarah Santos Gonçalves
- Laboratório Especial de Micologia, Disciplina de Infectologia, Escola Paulista de Medicina; Universidade Federal de São Paulo; São Paulo SP Brazil
| | - Ana Carolina Remondi Souza
- Laboratório Especial de Micologia, Disciplina de Infectologia, Escola Paulista de Medicina; Universidade Federal de São Paulo; São Paulo SP Brazil
| | - Anuradha Chowdhary
- Department of Medical Mycology; Vallabhbhai Patel Chest Institute; University of Delhi; Delhi India
| | - Jacques F. Meis
- Department of Medical Microbiology and Infectious Diseases; Canisius Wilhelmina Hospital; Nijmegen the Netherlands
- Department of Medical Microbiology; Radboud University Medical Centre; Nijmegen the Netherlands
| | - Arnaldo Lopes Colombo
- Laboratório Especial de Micologia, Disciplina de Infectologia, Escola Paulista de Medicina; Universidade Federal de São Paulo; São Paulo SP Brazil
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19
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Song JC, Stevens DA. Caspofungin: Pharmacodynamics, pharmacokinetics, clinical uses and treatment outcomes. Crit Rev Microbiol 2015; 42:813-46. [PMID: 26369708 DOI: 10.3109/1040841x.2015.1068271] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Over the past decade, echinocandins have emerged as first-line antifungal agents for many Candida infections. The echinocandins have a unique mechanism of action, inhibiting the synthesis of β-1,3-d-glucan polymers, key components of the cell wall in pathogenic fungi. Caspofungin was the first echinocandin antifungal agent to become licensed for use. The objectives of this review are to summarize the existing published data on caspofungin, under the subject headings of chemistry and mechanism of action, spectrum of activity, pharmacodynamics, pharmacokinetics, clinical studies, safety, drug interactions, dosing, and an overview of the drug's current place in therapy.
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Affiliation(s)
- Jessica C Song
- a Department of Pharmacy , Santa Clara Valley Medical Center , San Jose , CA , USA .,b California Institute for Medical Research , San Jose , CA , USA , and
| | - David A Stevens
- b California Institute for Medical Research , San Jose , CA , USA , and.,c Division of Infectious Diseases and Geographic Medicine , Stanford University School of Medicine , Stanford , CA , USA
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20
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Azevedo MM, Faria-Ramos I, Cruz LC, Pina-Vaz C, Rodrigues AG. Genesis of Azole Antifungal Resistance from Agriculture to Clinical Settings. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2015; 63:7463-8. [PMID: 26289797 DOI: 10.1021/acs.jafc.5b02728] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Azole fungal resistance is becoming a major public health problem in medicine in recent years. However, it was known in agriculture since several decades; the extensive use of these compounds results in contamination of air, plants, and soil. The increasing frequency of life-threatening fungal infections and the increase of prophylactical use of azoles in high-risk patients, taken together with the evolutionary biology evidence that drug selection pressure is an important factor for the emergence and spread of drug resistance, can result in a dramatic scenario. This study reviews the azole use in agricultural and medical contexts and discusses the hypothetical link between its extensive use and the emergence of azole resistance among human fungal pathogens.
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Affiliation(s)
- Maria-Manuel Azevedo
- Department of Microbiology, Faculty of Medicine, University of Porto , 4200-319 Porto, Portugal
- Center for Research in Health Technologies and Information Systems, Faculty of Medicine, University of Porto , 4200-319 Porto, Portugal
- School D. Maria II , Rua da Alegria, 4760-067 Vila Nova de Famalicão, Portugal
| | - Isabel Faria-Ramos
- Department of Microbiology, Faculty of Medicine, University of Porto , 4200-319 Porto, Portugal
- Center for Research in Health Technologies and Information Systems, Faculty of Medicine, University of Porto , 4200-319 Porto, Portugal
| | - Luísa Costa Cruz
- Department of Microbiology, Faculty of Medicine, University of Porto , 4200-319 Porto, Portugal
| | - Cidália Pina-Vaz
- Department of Microbiology, Faculty of Medicine, University of Porto , 4200-319 Porto, Portugal
- Center for Research in Health Technologies and Information Systems, Faculty of Medicine, University of Porto , 4200-319 Porto, Portugal
- Department of Clinical Pathology, Centro Hospitalar de São João , 4200-319 Porto, Portugal
| | - Acácio Gonçalves Rodrigues
- Department of Microbiology, Faculty of Medicine, University of Porto , 4200-319 Porto, Portugal
- Center for Research in Health Technologies and Information Systems, Faculty of Medicine, University of Porto , 4200-319 Porto, Portugal
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21
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Zavrel M, White TC. Medically important fungi respond to azole drugs: an update. Future Microbiol 2015; 10:1355-73. [DOI: 10.2217/fmb.15.47] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The increased numbers of patients with compromised immune systems in the last three decades have increased the chances of life-threatening fungal infections. Numerous antifungal drugs have been developed in the last 20 years to treat these infections. The largest group, the azoles, inhibits the synthesis of fungal sterols. The use of these fungistatic azoles has subsequently led to the emergence of acquired azole resistance. The most common mechanisms that result in azole resistance include the overexpression or mutation of the azole target enzyme, and overexpression of drug transporters that are responsible for azole efflux from cells. Additional, less-frequent mechanisms have also been identified. Understanding azole resistance mechanisms is crucial for current antifungal treatment and for the future development of new treatment strategies.
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Affiliation(s)
- Martin Zavrel
- University of Missouri-Kansas City, School of Biological Sciences, Division of Cell Biology & Biophysics, 5007 Rockhill Road, BSB 404, Kansas City, MO 64110, USA
| | - Theodore C White
- University of Missouri-Kansas City, School of Biological Sciences, Division of Cell Biology & Biophysics, 5007 Rockhill Road, BSB 404, Kansas City, MO 64110, USA
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22
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Sanchis M, Capilla J, Mayayo E, Pastor FJ, Guarro J. Experimental efficacy of anidulafungin againstAspergillus terreusspecies complex. Med Mycol 2015; 53:630-5. [DOI: 10.1093/mmy/myv027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 03/25/2015] [Indexed: 11/13/2022] Open
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23
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Gupta P, Khare V, Kumar D, Ahmad A, Banerjee G, Singh M. Comparative Evaluation of Disc Diffusion and E-test with Broth Micro-dilution in Susceptibility testing of Amphotericin B, Voriconazole and Caspofungin against Clinical Aspergillus isolates. J Clin Diagn Res 2015; 9:DC04-7. [PMID: 25737984 DOI: 10.7860/jcdr/2015/10467.5395] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 10/31/2014] [Indexed: 11/24/2022]
Abstract
BACKGROUND Clinical importance of Aspergillus has increased over the past few decades because of rise in immunosuppressive drugs and immune-modulating diseases. Antifungal susceptibility of Aspergillus is rarely performed by clinical laboratories because of lack of easier method. This study has investigated and compared susceptibility pattern of Aspergillus isolates by disc diffusion, E-test and broth micro-dilution for amphotericin B, voriconazole and caspofungin. MATERIALS AND METHODS Disk diffusion (DD) method of antifungal susceptibility (AFS) was evaluated for three different classes of antifungals: amphotericin B (AMB), voriconazole (VCZ) and caspofungin (CAS). Forty four clinical isolates of Aspergillus were selected; these included 34 A.fumigatus, 8 A.flavus and 2 A. terreus. AFS by DD and E-test was done on non-supplemented Mueller Hinton Agar (MHA) and was compared to Clinical Laboratory Standard Institute(CLSI) broth micro-dilution (BMD) method of AFS. RESULTS Disk diffusion method for amphotericin B showed 87.5% agreement while E-test showed 93.8% agreement with broth micro-dilution. The agreement with broth micro-dilution was similar for both disk diffusion and E-test in case of voriconazole (93.8%) and caspofungin (100%). 31.8% and 9.1% Aspergillus isolates were found to have amphotericin B and voriconazole MIC values above epidemiological cut off value (ECV) respectively. All isolates were within ECV for caspofungin. CONCLUSION CLSI method of DD promises to be easier, reproducible and cost effective method of susceptibility testing, but this method must be interpreted with caution in case of amphotericin B susceptibility testing. E-test correlates better than DD with BMD.
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Affiliation(s)
- Prashant Gupta
- Assistant Professor, Department of Microbiology, King George's Medical University , Lucknow, U.P, India
| | - Vineeta Khare
- Associate Professor, Department of Microbiology, Era's Lucknow Medical College , Sarfarajganj, Hardoi Road, U.P, India
| | - Deepak Kumar
- Resident Doctor, Department of Microbiology, King George's Medical University , Lucknow, U.P, India
| | - Abrar Ahmad
- Junior Research Fellow, Department of Microbiology, King George's Medical University , Lucknow, U.P, India
| | - Gopa Banerjee
- Professor, Department of Microbiology, King George's Medical University , Lucknow, U.P, India
| | - Mastan Singh
- Head of the Department, Department of Microbiology, King George's Medical University , Lucknow, U.P, India
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Perlin DS. Echinocandin resistance, susceptibility testing and prophylaxis: implications for patient management. Drugs 2014; 74:1573-85. [PMID: 25255923 PMCID: PMC4201113 DOI: 10.1007/s40265-014-0286-5] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
This article addresses the emergence of echinocandin resistance among Candida species, mechanisms of resistance, factors that promote resistance and confounding issues surrounding standard susceptibility testing. Fungal infections remain a significant cause of global morbidity and mortality, especially among patients with underlying immunosupression. Antifungal therapy is a critical component of patient management for acute and chronic diseases. Yet, therapeutic choices are limited due to only a few drug classes available to treat systemic disease. Moreover, the problem is exacerbated by the emergence of antifungal resistance, which has resulted in difficult to manage multidrug resistant strains. Echinocandin drugs are now the preferred choice to treat a range of candidiasis. These drugs target and inhibit the fungal-specific enzyme glucan synthase, which is responsible for the biosynthesis of a key cell wall polymer. Therapeutic failures involving acquisition of resistance among susceptible organisms like Candida albicans is largely a rare event. However, in recent years, there is an alarming trend of increased resistance among strains of Candida glabrata, which in many cases are also resistant to azole drugs. Echinocandin resistance is always acquired during therapy and the mechanism of resistance is well established to involve amino acid changes in "hot-spot" regions of the Fks subunits carrying the catalytic portion of glucan synthase. These changes significantly decrease the sensitivity of the enzyme to drug resulting in higher MIC values. A range of drug responses, from complete to partial refractory response, is observed depending on the nature of the amino acid substitution, and clinical responses are recapitulated in pharmacodynamic models of infection. The cellular processes promoting the formation of resistant Fks strains involve complex stress response pathways, which yield a variety of adaptive compensatory genetic responses. Stress-adapted cells become drug tolerant and can form stable drug resistant FKS mutations with continued drug exposure. A major concern for resistance detection is that classical broth microdilution techniques show significant variability among clinical microbiology laboratories for certain echinocandin drugs and Candida species. The consequence is that susceptible strains are misclassified according to established clinical breakpoints, and this has led to confusion in the field. Clinical factors that appear to promote echinocandin resistance include the expanding use of antifungal agents for empiric therapy and prophylaxis. Furthermore, host reservoirs such as biofilms in the gastrointestinal tract or intra-abdominal infections can seed development of resistant organisms during therapy. A fundamental understanding of the primary molecular resistance mechanism, along with cellular and clinical factors that promote resistance emergence, is critical to develop better diagnostic tools and therapeutic strategies to overcome and prevent echinocandin resistance.
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Affiliation(s)
- David S Perlin
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, 07103, USA,
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Enoch D, Idris S, Aliyu S, Micallef C, Sule O, Karas J. Micafungin for the treatment of invasive aspergillosis. J Infect 2014; 68:507-26. [DOI: 10.1016/j.jinf.2014.01.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 01/06/2014] [Accepted: 01/15/2014] [Indexed: 10/25/2022]
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Lass-Flörl C. Susceptibility testing in Aspergillus species complex. Clin Microbiol Infect 2014; 20 Suppl 6:49-53. [PMID: 24372722 DOI: 10.1111/1469-0691.12514] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 11/18/2013] [Accepted: 11/18/2013] [Indexed: 11/27/2022]
Abstract
Methods for susceptibility testing of Aspergillus are developed and validated by the European Committee on Antibiotic Susceptibility Testing Subcommittee on Antifungal Susceptibility Testing. Breakpoints for phenotypic antimicrobial susceptibility testing have been determined by breakpoint committees and as part of regulatory processes for the approval of new drugs. Dosages, pharmacokinetics, resistance mechanisms, MIC distributions, pharmacodynamics and epidemiological cut-off values are used in the breakpoint-setting process. Clinical breakpoints are for everyday use in the clinical laboratory to advise on patient therapy. Resistance in Aspergillus fumigatus has been increasingly reported since standards became available.
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Affiliation(s)
- C Lass-Flörl
- Division of Hygiene and Medical Microbiology, Innsbruck Medical University, Innsbruck, Austria
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Arendrup MC. Update on antifungal resistance in Aspergillus and Candida. Clin Microbiol Infect 2014; 20 Suppl 6:42-8. [PMID: 24372701 DOI: 10.1111/1469-0691.12513] [Citation(s) in RCA: 157] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 11/18/2013] [Accepted: 11/18/2013] [Indexed: 11/28/2022]
Abstract
Antifungal resistance in Candida and Aspergillus may be either intrinsic or acquired and may be encountered in the antifungal drug exposed but also the antifungal drug-naïve patient. Prior antifungal treatment confers a selection pressure and notoriously raises the awareness of possible resistance in patients failing therapy, thus calling for susceptibility testing. On the contrary, antifungal resistance in the drug-naïve patient is less expected and therefore more challenging. This is particularly true when it concerns pathogens with acquired resistance which cannot be predicted from the species identification itself. This scenario is particularly relevant for A. fumigatus infections due to the increasing prevalence of azole-resistant isolates in the environment. For Candida, infections resistance is most common in the context of increasing prevalence of species with intrinsic resistance. Candida glabrata which has intrinsically reduced susceptibility to fluconazole is increasingly common particularly among the adult and elderly population on the Northern Hemisphere where it may be responsible for as many as 30% of the blood stream infections in population-based surveillance programmes. Candida parapsilosis is prevalent in the paediatric setting, at centres with increasing echinocandin use and at the southern or pacific parts of the world. In the following, the prevalence and drivers of intrinsic and acquired resistance in Aspergillus and Candida will be reviewed.
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Affiliation(s)
- M C Arendrup
- Unit of Mycology and Parasitology, Department Microbiology and Infection Control, Statens Serum Institut, Copenhagen, Denmark
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Cantón E, Espinel-Ingroff A, Pemán J. Trends in antifungal susceptibility testing using CLSI reference and commercial methods. Expert Rev Anti Infect Ther 2014; 7:107-19. [DOI: 10.1586/14787210.7.1.107] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Aimanianda V, Latgé JP. Problems and hopes in the development of drugs targeting the fungal cell wall. Expert Rev Anti Infect Ther 2014; 8:359-64. [DOI: 10.1586/eri.10.13] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Tobal JM, Balieiro MEDSF. Role of carbonic anhydrases in pathogenic micro-organisms: a focus on Aspergillus fumigatus. J Med Microbiol 2014; 63:15-27. [DOI: 10.1099/jmm.0.064444-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Aspergillus fumigatus is a ubiquitous saprophytic fungus responsible for organic material decomposition, and plays an important role in recycling environmental carbon and nitrogen. Besides its important role in the environment, this fungus has been reported as one of the most important fungal pathogens in immunocompromised patients. Due to changes in CO2 concentration that some pathogens face during the infection process, studies have been undertaken to understand the pathogenic roles of carbonic anhydrases (CAs), well-known CO2 hydration catalytic enzymes. As a basis for a discussion of the possible roles of CAs in A. fumigatus pathogenicity, this review describes the main characteristics of the A. fumigatus infection and the challenges for its treatment. In addition, it gathers findings from studies with CA inhibitor drugs as anti-infective agents in different pathogens.
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Affiliation(s)
- Jaqueline Moisés Tobal
- Faculty of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, São Paulo, Brazil
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In vitro analyses of mild heat stress in combination with antifungal agents against Aspergillus fumigatus biofilm. Antimicrob Agents Chemother 2013; 58:1443-50. [PMID: 24342649 DOI: 10.1128/aac.01007-13] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Aspergillus fumigatus biofilms still present a challenge for effective treatment in clinical settings. While mild heat stress has been introduced as a treatment for infectious diseases, the effectiveness of mild heat stress on A. fumigatus biofilm formation and antifungal susceptibility is still unknown. In the present study, confocal laser scanning microscopy (CLSM) was used to image and quantify Aspergillus fumigatus biofilm formation under three different regimens of continuous mild heat stress: at 37, 39, and 41°C. Furthermore, fungal growth has been investigated under the above conditions in combination with antifungal drugs (amphotericin B [AMB], micafungin [MCF], and voriconazole [VOC]) at early and late stages. CLSM analysis showed that higher temperatures induce earlier germination and greater hyphal elongation but poorer polar growth and reduced biofilm thickness. In the early stage of biofilm formation, the combination of treatment at 39 or 41°C with MCF or VOC produced no visible difference in biomass formation from similar treatments at 37°C with the same drug. Interestingly, AMB treatment at 37°C inhibited early stage biofilm formation to a much greater extent than at 39 and 41°C. At the late stage of biofilm formation, the mild heat treatments at 39 and 41°C with AMB, MCF, and VOC inhibited biomass formation compared to that at 37°C. The present data show that mild heat stress has a negative regulatory effect on biofilm formation in vitro, and antifungal drug improvement with mild heat treatment at late-stage biofilm formation provides useful indications of possible effective strategies for clinical management of aspergillosis.
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Breakthrough filamentous fungal infections in pediatric hematopoetic stem cell transplant and oncology patients receiving caspofungin. CANADIAN JOURNAL OF INFECTIOUS DISEASES & MEDICAL MICROBIOLOGY 2013; 23:179-82. [PMID: 24294271 DOI: 10.1155/2012/957973] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
BACKGROUND Caspofungin is an echinocandin class antifungal medication that is commonly used empirically in immunocompromised patients at high risk for invasive fungal disease. OBJECTIVE To describe the clinical characteristics of breakthrough fungal infections in pediatric hematopoetic stem cell transplant recipients, and oncology and hematology patients receiving caspofungin. METHODS A five-year retrospective review, from 2004 through 2008, of all cases of proven invasive filamentous fungal infection of children admitted to The Hospital for Sick Children (Toronto, Ontario) was conducted. A breakthrough infection was defined as new onset of symptoms that were later proven to be due to an invasive mold infection on day 3 or later after initiation of caspofungin therapy. RESULTS Six confirmed positive cultures (Aspergillus fumigatus [two cases], Aspergillus niger, Fusarium oxysporum, Alternaria infectoria and Rhizomucor pusillus) met the criteria for breakthrough filamentous mold infection while on caspofungin therapy. Underlying immunocompromising conditions included acute lymphoblastic leukemia (two cases), acute myeloid leukemia (two cases), Burkitt's lymphoma and aplastic anemia. Four of the patients underwent a hematopoetic stem cell transplant. All patients received a lipid amphotericin B product as part of their treatment for breakthrough infection. Five patients also received voriconazole and one received posaconazole. Four of the six patients died and two responded with a clinical and microbiological cure. DISCUSSION There are few descriptions of breakthrough fungal infections in pediatric patients receiving caspofungin. The six cases presented here, all microbiologically proven, are likely only a fraction of the total number of possible breakthrough invasive fungal infections that occured over the study period. CONCLUSION Clinicians must remain aware that breakthrough fungal infections by species not covered by particular antifungals, including caspofungin, do occur and may have poor outcomes.
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Lelièvre L, Groh M, Angebault C, Maherault AC, Didier E, Bougnoux ME. Azole resistant Aspergillus fumigatus: an emerging problem. Med Mal Infect 2013; 43:139-45. [PMID: 23562488 DOI: 10.1016/j.medmal.2013.02.010] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 01/21/2013] [Accepted: 02/20/2013] [Indexed: 11/25/2022]
Abstract
Azole resistance has appeared recently in Aspergillus fumigatus and increased dangerously in the last decade. The main resistance mechanism is a point mutation of CYP51A, the gene encoding 14α-sterol demethylase, the target enzyme of azole antifungal drugs. This mutation can induce resistance to itraconazole alone or multi-azole resistance. CYP51A mutation can occur in two cases. The first usually concerns patients receiving long-term azole therapy, most of the time for chronic aspergillosis, and involves a wide range of mutations. The second is due to the use of azole fungicides in agriculture. The latter favors a single mutagenesis event: a substitution of leucine for histidine at codon 98 and the tandem repeat of a 34-base pair tandem sequence in the CYP51A gene promoter region. This confers cross-resistance to all azole antifungal drugs. This emerging and environmentally linked issue is of growing concern for the management of antifungal therapy. This mechanism of resistance was first described in the Netherlands and is now reported worldwide. It may have become the leading mechanism of azole resistance in A. fumigatus. Azoles are major agents for the treatment of aspergillosis, and the only oral antifungals. Infection with antifungal-resistant strains is correlated with treatment failure. This emerging phenomenon stresses the urgent need for new preventive strategies (controlled use of antifungals and azole prophylaxis), new diagnostic strategies (early detection of resistance), and new therapeutic strategies in the management of A. fumigatus infections.
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Affiliation(s)
- L Lelièvre
- Unité de bactériologie, service de microbiologie, hôpital Necker-Enfants-Malades, Assistance publique-Hôpitaux de Paris, rue Vaugirard, 75015 Paris, France.
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Eschenauer GA, Carver PL. The Evolving Role of Antifungal Susceptibility Testing. Pharmacotherapy 2013; 33:465-75. [DOI: 10.1002/phar.1233] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
| | - Peggy L. Carver
- University of Pittsburgh Medical Center; Pittsburgh; Pennsylvania
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Echinocandins: production and applications. Appl Microbiol Biotechnol 2013; 97:3267-84. [PMID: 23463246 DOI: 10.1007/s00253-013-4761-9] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 02/06/2013] [Accepted: 02/07/2013] [Indexed: 10/27/2022]
Abstract
The first echinocandin-type antimycotic (echinocandin B) was discovered in the 1970s. It was followed by the isolation of more than 20 natural echinocandins. These cyclic lipo-hexapeptides are biosynthesized on non-ribosomal peptide synthase complexes by different ascomycota fungi. They have a unique mechanism of action; as non-competitive inhibitors of β-1,3-glucan synthase complex they target the fungal cell wall. Results of the structure-activity relationship experiments let us develop semisynthetic derivatives with improved properties. Three cyclic lipohiexapeptides (caspofungin, micafungin and anidulafungin) are currently approved for use in clinics. As they show good fungicidal (Candida spp.) or fungistatic (Aspergillus spp.) activity against the most important human pathogenic fungi including azole-resistant strains, they are an important addition to the antifungal armamentarium. Some evidence of acquired resistance against echinocandins has been detected among Candida glabrata strains in recent years, which enhanced the importance of data collected on the mechanism of acquired resistance developing against the echinocandins. In this review, we show the structural diversity of natural echinocandins, and we summarize the emerging data on their mode of action, biosynthesis and industrial production. Their clinical significance as well as the mechanism of natural and acquired resistance is also discussed.
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In vitro activity of a new oral glucan synthase inhibitor (MK-3118) tested against Aspergillus spp. by CLSI and EUCAST broth microdilution methods. Antimicrob Agents Chemother 2012; 57:1065-8. [PMID: 23229479 DOI: 10.1128/aac.01588-12] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
MK-3118, a glucan synthase inhibitor derived from enfumafungin, and comparator agents were tested against 71 Aspergillus spp., including itraconazole-resistant strains (MIC, ≥ 4 μg/ml), using CLSI and EUCAST reference broth microdilution methods. The CLSI 90% minimum effective concentration (MEC(90))/MIC(90) values (μg/ml) for MK-3118, amphotericin B, and caspofungin, respectively, were as follows: 0.12, 2, and 0.03 for Aspergillus flavus species complex (SC); 0.25, 2, and 0.06 for Aspergillus fumigatus SC; 0.12, 2, and 0.06 for Aspergillus terreus SC; and 0.06, 1, and 0.03 for Aspergillus niger SC. Essential agreement between the values found by CLSI and EUCAST (± 2 log(2) dilution steps) was 94.3%. MK-3118 was determined to be a potent agent regardless of the in vitro method applied, with excellent activity against contemporary wild-type and itraconazole-resistant strains of Aspergillus spp.
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Interaction of platelets and anidulafungin against Aspergillus fumigatus. Antimicrob Agents Chemother 2012; 57:626-8. [PMID: 23114752 DOI: 10.1128/aac.01534-12] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The combination of platelets and anidulafungin at 0.03 μg/ml significantly (P < 0.05) reduced the germination rate and hyphal elongation in Aspergillus fumigatus compared to those with either anidulafungin only or an untreated control. Platelets decreased the expression of the fks gene, which plays an important role in cell wall synthesis. Our results suggest that human platelets plus anidulafungin might contribute to defense against A. fumigatus.
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Schmalreck A, Willinger B, Czaika V, Fegeler W, Becker K, Blum G, Lass-Flörl C. Susceptibility screening of hyphae-forming fungi with a new, easy, and fast inoculum preparation method. Mycopathologia 2012; 174:467-74. [PMID: 22864604 DOI: 10.1007/s11046-012-9570-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 07/19/2012] [Indexed: 11/30/2022]
Abstract
In vitro susceptibility testing of clinically important fungi becomes more and more essential due to the rising number of fungal infections in patients with impaired immune system. Existing standardized microbroth dilution methods for in vitro testing of molds (CLSI, EUCAST) are not intended for routine testing. These methods are very time-consuming and dependent on sporulating of hyphomycetes. In this multicentre study, a new (independent of sporulation) inoculum preparation method (containing a mixture of vegetative cells, hyphae, and conidia) was evaluated. Minimal inhibitory concentrations (MIC) of amphotericin B, posaconazole, and voriconazole of 180 molds were determined with two different culture media (YST and RPMI 1640) according to the DIN (Deutsches Institut für Normung) microdilution assay. 24 and 48 h MIC of quality control strains, tested per each test run, prepared with the new inoculum method were in the range of DIN. YST and RPMI 1640 media showed similar MIC distributions for all molds tested. MIC readings at 48 versus 24 h yield 1 log(2) higher MIC values and more than 90 % of the MICs read at 24 and 48 h were within ± 2 log(2) dilution. MIC end point reading (log(2 MIC-RPMI 1640)-log(2 MIC-YST)) of both media demonstrated a tendency to slightly lower MICs with RPMI 1640 medium. This study reports the results of a new, time-saving, and easy-to-perform method for inoculum preparation for routine susceptibility testing that can be applied for all types of spore-/non-spore and hyphae-forming fungi.
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Tóth V, Nagy CT, Pócsi I, Emri T. The echinocandin B producer fungus Aspergillus nidulans var. roseus ATCC 58397 does not possess innate resistance against its lipopeptide antimycotic. Appl Microbiol Biotechnol 2012; 95:113-22. [PMID: 22555909 DOI: 10.1007/s00253-012-4027-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Revised: 03/12/2012] [Accepted: 03/13/2012] [Indexed: 12/01/2022]
Abstract
Aspergillus nidulans var. roseus ATCC 58397 is an echinocandin B (ECB) producer ascomycete with great industrial importance. As demonstrated by ECB/caspofungin sensitivity assays, A. nidulans var. roseus does not possess any inherent resistance to echinocandins, and its tolerance to these lipopeptide antimycotics are even lower than those of the non-producer A. nidulans FGSC A4 strain. Under ECB producing conditions or ECB exposures, A. nidulans var. roseus induced its ECB tolerance via up-regulating elements of the chitin biosynthetic machinery and, hence, through changing dynamically the composition of its own cell wall. Importantly, although the specific β-1,3-glucan synthase activity was elevated, these changes reduced the β-glucan content of hyphae considerably, but the expression of fksA, encoding the catalytic subunit of β-1,3-glucan synthase, the putative target of echinocandins in the aspergilli, was not affected. These data suggest that compensatory chitin biosynthesis is the centerpiece of the induced ECB tolerance of A. nidulans var. roseus. It is important to note that the induced tolerance to ECB (although resulted in paradoxical growth at higher ECB concentrations) was accompanied with reduced growth rate and, under certain conditions, even sensitized the fungus to other stress-generating agents like SDS. We hypothesize that although ECB-resistant mutants may arise in vivo in A. nidulans var. roseus cultures, their widespread propagation is severely restricted by the disadvantageous physiological effects of such mutations.
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Affiliation(s)
- Viktória Tóth
- Department of Microbial Biotechnology and Cell Biology, Faculty of Science and Technology, University of Debrecen, 4032 Debrecen, Hungary
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Anjos J, Fernandes C, Silva BMA, Quintas C, Abrunheiro A, Gow NAR, Gonçalves T. β(1,3)-glucan synthase complex from Alternaria infectoria, a rare dematiaceous human pathogen. Med Mycol 2012; 50:716-25. [PMID: 22548239 DOI: 10.3109/13693786.2012.675525] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The fungal cell wall polymer β-(1,3)-D-glucan is synthesized by the enzyme β-(1,3)- D-glucan synthase that is a complex composed of at least two proteins, Rho1p and Fks1p. Here, we report the nucleotide sequence of a single FKS gene and of the regulatory unit, RHO1 from the dematiaceous pathogenic fungus Alternaria infectoria. The predicted AiFks and AiRho share, respectively, 93% and 100% identity with that of Drechslera tritici-repentis. We also report that the sensitivity to caspofungin of eight different A. infectoria clinical strains is similar, with a MIC > 32 µg/ml and a MEC of 1 µg/ml, except for one strain which had a MEC of 1.4 µg/ml. This same strain exhibited one substitution at the hot spot 2, S1405A, compatible with less susceptible phenotypes, with the other seven strains having no mutations in either hot spot 1 or 2. The relative quantification of the expression of AiFKS and of AiRHO demonstrated a decrease in response to an exposure to caspofungin at 0.5 µg/ml.
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Affiliation(s)
- Jorge Anjos
- CNC-Centre for Neurosciences and Cell Biology, University of Coimbra, Portugal
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Blum G, Kainzner B, Grif K, Dietrich H, Zeiger B, Sonnweber T, Lass-Flörl C. In vitro and in vivo role of heat shock protein 90 in Amphotericin B resistance of Aspergillus terreus. Clin Microbiol Infect 2012; 19:50-55. [PMID: 22515428 DOI: 10.1111/j.1469-0691.2012.03848.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Aspergillus terreus (A. terreus) is of serious concern because of a high propensity to dissemination and in vitro and in vivo resistance to Amphotericin B (AmB). The underlying molecular mechanism of AmB is not known yet and here we want to explore whether fungal heat shock protein 90 (HSP90) is involved in polyene resistance in A. terreus. AmB-susceptible (ATS) and AmB-resistant (ATR) A. terreus and AmB-susceptible Aspergillus fumigatus (AFS) were investigated in response to AmB with a special focus on HSP90. HSP90 inhibitors resulted in significant improvement of AmB activity against ATR as minimum inhibitory concentrations (MIC) decreased from 32 to 0.38 mg/L. Gene expression profiling showed a greater basal amount of HSP90 levels in ATR and ATS when compared with AFS. HSP90 blockers in combination with AmB were evaluated in a murine model of disseminated aspergillosis. HSP90 inhibitors were not beneficial for mice infected with ATR, and neither mono- nor combination treatment with AmB yielded clinical improvement. HSP90 inhibition with 17-allylamino-17-demethoxygeldanamycin (17-AAG) was harmful. HSP90 seems to play a vital role in antifungal stress response in all aspergilli tested, whereas HSP90 does not substantiate the origin of AmB resistance in ATR.
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Affiliation(s)
- G Blum
- Division of Hygiene and Medical Microbiology, Innsbruck Medical University.
| | - B Kainzner
- Division of Hygiene and Medical Microbiology, Innsbruck Medical University
| | - K Grif
- Division of Hygiene and Medical Microbiology, Innsbruck Medical University
| | - H Dietrich
- Innsbruck Central Animal Experiment Station
| | - B Zeiger
- Department of Pathology, Innsbruck Medical University
| | - T Sonnweber
- Department of Internal Medicine I, Innsbruck Medical University, Innsbruck, Austria
| | - C Lass-Flörl
- Division of Hygiene and Medical Microbiology, Innsbruck Medical University
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van der Linden JWM, Snelders E, Kampinga GA, Rijnders BJA, Mattsson E, Debets-Ossenkopp YJ, Kuijper EJ, Van Tiel FH, Melchers WJG, Verweij PE. Clinical implications of azole resistance in Aspergillus fumigatus, The Netherlands, 2007-2009. Emerg Infect Dis 2012; 17:1846-54. [PMID: 22000354 PMCID: PMC3311118 DOI: 10.3201/eid1710.110226] [Citation(s) in RCA: 347] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The prevalence and spread of azole resistance in clinical Aspergillus fumigatus isolates in the Netherlands are currently unknown. Therefore, we performed a prospective nationwide multicenter surveillance study to determine the effects of resistance on patient management strategies and public health. From June 2007 through January 2009, all clinical Aspergillus spp. isolates were screened for itraconazole resistance. In total, 2,062 isolates from 1,385 patients were screened; the prevalence of itraconazole resistance in A. fumigatus in our patient cohort was 5.3% (range 0.8%-9.5%). Patients with a hematologic or oncologic disease were more likely to harbor an azole-resistant isolate than were other patient groups (p<0.05). Most patients (64.0%) from whom a resistant isolate was identified were azole naive, and the case-fatality rate of patients with azole-resistant invasive aspergillosis was 88.0%. Our study found that multiazole resistance in A. fumigatus is widespread in the Netherlands and is associated with a high death rate for patients with invasive aspergillosis.
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Hadrich I, Makni F, Neji S, Abbes S, Cheikhrouhou F, Trabelsi H, Sellami H, Ayadi A. Invasive Aspergillosis: Resistance to Antifungal Drugs. Mycopathologia 2012; 174:131-41. [DOI: 10.1007/s11046-012-9526-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Accepted: 01/23/2012] [Indexed: 11/29/2022]
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Arendrup MC, Bille J, Dannaoui E, Ruhnke M, Heussel CP, Kibbler C. ECIL-3 classical diagnostic procedures for the diagnosis of invasive fungal diseases in patients with leukaemia. Bone Marrow Transplant 2012; 47:1030-45. [DOI: 10.1038/bmt.2011.246] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
Antifungal resistance continues to grow and evolve and complicate patient management, despite the introduction of new antifungal agents. In vitro susceptibility testing is often used to select agents with likely activity for a given infection, but perhaps its most important use is in identifying agents that will not work, i.e., to detect resistance. Standardized methods for reliable in vitro antifungal susceptibility testing are now available from the Clinical and Laboratory Standards Institute (CLSI) in the United States and the European Committee on Antimicrobial Susceptibility Testing (EUCAST) in Europe. Data gathered by these standardized tests are useful (in conjunction with other forms of data) for calculating clinical breakpoints and epidemiologic cutoff values (ECVs). Clinical breakpoints should be selected to optimize detection of non-wild-type (WT) strains of pathogens, and they should be species-specific and not divide WT distributions of important target species. ECVs are the most sensitive means of identifying strains with acquired resistance mechanisms. Various mechanisms can lead to acquired resistance of Candida species to azole drugs, the most common being induction of the efflux pumps encoded by the MDR or CDR genes, and acquisition of point mutations in the gene encoding for the target enzyme (ERG11). Acquired resistance of Candida species to echinocandins is typically mediated via acquisition of point mutations in the FKS genes encoding the major subunit of its target enzyme. Antifungal resistance is associated with elevated minimum inhibitory concentrations, poorer clinical outcomes, and breakthrough infections during antifungal treatment and prophylaxis. Candidemia due to Candida glabrata is becoming increasingly common, and C glabrata isolates are increasingly resistant to both azole and echinocandin antifungal agents. This situation requires continuing attention. Rates of azole-resistant Aspergillus fumigatus are currently low, but there are reports of emerging resistance, including multi-azole resistant isolates in parts of Europe.
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Colosi IA, Faure O, Dessaigne B, Bourdon C, Lebeau B, Colosi HA, Pelloux H. Susceptibility of 100 filamentous fungi: comparison of two diffusion methods, Neo-Sensitabs and E-test, for amphotericin B, caspofungin, itraconazole, voriconazole and posaconazole. Med Mycol 2011; 50:378-85. [PMID: 21981028 DOI: 10.3109/13693786.2011.616543] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We compared the E-test method to that of the Neo-Sensitabs tablet diffusion assay for evaluating the in vitro susceptibility of 100 clinical isolates of filamentous fungi (Aspergillus spp., Fusarium spp., Scedosporium spp., zygomycetes and other molds) to amphotericin B, itraconazole, voriconazole, caspofungin, and posaconazole. We determined the categorical agreement level between E-test minimum inhibitory concentrations (MIC) and tablet end-points, as opposed to the following disagreement parameters: very major error - resistant parameter (R) in E-test and susceptible (S) in tablet; major error - S by E-test and R by tablet; minor error - shifts between S and susceptible dose-dependent (S-DD) or S-DD and R. We also performed linear regression analyses and computed Pearson's correlation coefficients (R values) between the log transforms of MICs and the inhibition zone diameters of the five studied antifungal agents. For itraconazole we obtained 97% categorical agreement and R = -0.727. Categorical agreement for caspofungin and voriconazole was 96% and R =-0.821 and R = -0.789, respectively. For posaconazole the categorical agreement was 94% and R =-0.743. Amphotericin B exhibited a lower degree of agreement (76%, R = -0.672), especially in studies of Aspergillus spp. Our results suggest a potential value of the Neo-Sensitabs assay for in vitro susceptibility testing of molds to itraconazole, voriconazole, caspofungin and posaconazole, while amphotericin B exhibited an overall lower degree of agreement.
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Affiliation(s)
- Ioana A Colosi
- Iuliu Haţieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania.
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