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Pham D, Sivalingam V, Tang HM, Montgomery JM, Chen SCA, Halliday CL. Molecular Diagnostics for Invasive Fungal Diseases: Current and Future Approaches. J Fungi (Basel) 2024; 10:447. [PMID: 39057332 PMCID: PMC11278267 DOI: 10.3390/jof10070447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 06/21/2024] [Accepted: 06/24/2024] [Indexed: 07/28/2024] Open
Abstract
Invasive fungal diseases (IFDs) comprise a growing healthcare burden, especially given the expanding population of immunocompromised hosts. Early diagnosis of IFDs is required to optimise therapy with antifungals, especially in the setting of rising rates of antifungal resistance. Molecular techniques including nucleic acid amplification tests and whole genome sequencing have potential to offer utility in overcoming limitations with traditional phenotypic testing. However, standardisation of methodology and interpretations of these assays is an ongoing undertaking. The utility of targeted Aspergillus detection has been well-defined, with progress in investigations into the role of targeted assays for Candida, Pneumocystis, Cryptococcus, the Mucorales and endemic mycoses. Likewise, whilst broad-range polymerase chain reaction assays have been in use for some time, pathology stewardship and optimising diagnostic yield is a continuing exercise. As costs decrease, there is also now increased access and experience with whole genome sequencing, including metagenomic sequencing, which offers unparalleled resolution especially in the investigations of potential outbreaks. However, their role in routine diagnostic use remains uncommon and standardisation of techniques and workflow are required for wider implementation.
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Affiliation(s)
- David Pham
- Centre for Infectious Diseases and Microbiology Laboratory Services, Institute of Clinical Pathology and Medical Research, NSW Health Pathology, Westmead Hospital, Westmead, NSW 2145, Australia; (D.P.)
| | - Varsha Sivalingam
- Centre for Infectious Diseases and Microbiology Laboratory Services, Institute of Clinical Pathology and Medical Research, NSW Health Pathology, Westmead Hospital, Westmead, NSW 2145, Australia; (D.P.)
| | - Helen M. Tang
- Centre for Infectious Diseases and Microbiology Laboratory Services, Institute of Clinical Pathology and Medical Research, NSW Health Pathology, Westmead Hospital, Westmead, NSW 2145, Australia; (D.P.)
| | - James M. Montgomery
- Centre for Infectious Diseases and Microbiology Laboratory Services, Institute of Clinical Pathology and Medical Research, NSW Health Pathology, Westmead Hospital, Westmead, NSW 2145, Australia; (D.P.)
| | - Sharon C.-A. Chen
- Centre for Infectious Diseases and Microbiology Laboratory Services, Institute of Clinical Pathology and Medical Research, NSW Health Pathology, Westmead Hospital, Westmead, NSW 2145, Australia; (D.P.)
- Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW 2006, Australia
- Sydney Infectious Diseases Institute, The University of Sydney, Westmead, NSW 2145, Australia
| | - Catriona L. Halliday
- Centre for Infectious Diseases and Microbiology Laboratory Services, Institute of Clinical Pathology and Medical Research, NSW Health Pathology, Westmead Hospital, Westmead, NSW 2145, Australia; (D.P.)
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Scharmann U, Verhasselt HL, Kirchhoff L, Furnica DT, Steinmann J, Rath PM. Microbiological Non-Culture-Based Methods for Diagnosing Invasive Pulmonary Aspergillosis in ICU Patients. Diagnostics (Basel) 2023; 13:2718. [PMID: 37627977 PMCID: PMC10453445 DOI: 10.3390/diagnostics13162718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/17/2023] [Accepted: 08/18/2023] [Indexed: 08/27/2023] Open
Abstract
The diagnosis of invasive pulmonary aspergillosis (IPA) in intensive care unit (ICU) patients is crucial since most clinical signs are not specific to invasive fungal infections. To detect an IPA, different criteria should be considered. Next to host factors and radiological signs, microbiological criteria should be fulfilled. For microbiological diagnostics, different methods are available. Next to the conventional culture-based approaches like staining and culture, non-culture-based methods can increase sensitivity and improve time-to-result. Besides fungal biomarkers, like galactomannan and (1→3)-β-D-glucan as nonspecific tools, molecular-based methods can also offer detection of resistance determinants. The detection of novel biomarkers or targets is promising. In this review, we evaluate and discuss the value of non-culture-based microbiological methods (galactomannan, (1→3)-β-D-glucan, Aspergillus PCR, new biomarker/targets) for diagnosing IPA in ICU patients.
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Affiliation(s)
- Ulrike Scharmann
- Institute of Medical Microbiology, University Hospital Essen, University of Duisburg-Essen, 45122 Essen, Germany (J.S.)
| | - Hedda Luise Verhasselt
- Institute of Medical Microbiology, University Hospital Essen, University of Duisburg-Essen, 45122 Essen, Germany (J.S.)
| | - Lisa Kirchhoff
- Institute of Medical Microbiology, University Hospital Essen, University of Duisburg-Essen, 45122 Essen, Germany (J.S.)
| | - Dan-Tiberiu Furnica
- Institute of Medical Microbiology, University Hospital Essen, University of Duisburg-Essen, 45122 Essen, Germany (J.S.)
| | - Joerg Steinmann
- Institute of Medical Microbiology, University Hospital Essen, University of Duisburg-Essen, 45122 Essen, Germany (J.S.)
- Institute of Clinical Hygiene, Medical Microbiology and Infectiology, Klinikum Nürnberg, Paracelsus Medical University, 90419 Nuremberg, Germany
| | - Peter-Michael Rath
- Institute of Medical Microbiology, University Hospital Essen, University of Duisburg-Essen, 45122 Essen, Germany (J.S.)
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Bosetti D, Neofytos D. Invasive Aspergillosis and the Impact of Azole-resistance. CURRENT FUNGAL INFECTION REPORTS 2023; 17:1-10. [PMID: 37360857 PMCID: PMC10024029 DOI: 10.1007/s12281-023-00459-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/04/2023] [Indexed: 06/28/2023]
Abstract
Purpose of Review IA (invasive aspergillosis) caused by azole-resistant strains has been associated with higher clinical burden and mortality rates. We review the current epidemiology, diagnostic, and therapeutic strategies of this clinical entity, with a special focus on patients with hematologic malignancies. Recent Findings There is an increase of azole resistance in Aspergillus spp. worldwide, probably due to environmental pressure and the increase of long-term azole prophylaxis and treatment in immunocompromised patients (e.g., in hematopoietic stem cell transplant recipients). The therapeutic approaches are challenging, due to multidrug-resistant strains, drug interactions, side effects, and patient-related conditions. Summary Rapid recognition of resistant Aspergillus spp. strains is fundamental to initiate an appropriate antifungal regimen, above all for allogeneic hematopoietic cell transplantation recipients. Clearly, more studies are needed in order to better understand the resistance mechanisms and optimize the diagnostic methods to identify Aspergillus spp. resistance to the existing antifungal agents/classes. More data on the susceptibility profile of Aspergillus spp. against the new classes of antifungal agents may allow for better treatment options and improved clinical outcomes in the coming years. In the meantime, continuous surveillance studies to monitor the prevalence of environmental and patient prevalence of azole resistance among Aspergillus spp. is absolutely crucial.
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Affiliation(s)
- Davide Bosetti
- Division of Infectious Diseases, Geneva University Hospitals, Rue Gabrielle-Perret-Gentil 4, Geneva, Switzerland
| | - Dionysios Neofytos
- Division of Infectious Diseases, Geneva University Hospitals, Rue Gabrielle-Perret-Gentil 4, Geneva, Switzerland
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Mendonça A, Carvalho-Pereira J, Franco-Duarte R, Sampaio P. Optimization of a Quantitative PCR Methodology for Detection of Aspergillus spp. and Rhizopus arrhizus. Mol Diagn Ther 2022; 26:511-525. [PMID: 35710958 PMCID: PMC9202985 DOI: 10.1007/s40291-022-00595-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/02/2022] [Indexed: 11/25/2022]
Abstract
Introduction Multiplex quantitative polymerase chain reaction (qPCR) methods for the detection of Aspergillus spp. based only on SYBR Green and melting curve analysis of PCR products are difficult to develop because most targets are located within ITS regions. The aim of this study was to adapt our previously developed methodology based on a multiplex PCR assay coupled with GeneScan analysis to provide a qPCR method. Methods A SYBR Green-based real-time PCR assay was optimized to detect A. fumigatus, A. flavus, A. niger, A. terreus, and R. arrhizus in a multiplex assay and applied to cultured fungi and spiked plasma. Results Different melting temperatures allowed identification of all five pathogens and discrimination between them, even in samples with low amounts of fungal gDNA (from 1.3 to 33.0 pg/μL), which has been reported previously as problematic. No false-positive results were obtained for non-target species, including bacteria and human DNA. This method allowed detection of fungal pathogens in human plasma spiked with fungal DNA and in coinfections of A. niger/R. arrhizus. Discussion This work provides evidence for the use of a qPCR multiplex method based on SYBR Green and melting curve analysis of PCR products for the detection of A. fumigatus, A. flavus, A. niger, A. terreus, and R. arrhizus. The proposed method is simpler and less expensive than available kits based on fluorescent probes and can be used for aiding diagnosis of the most relevant invasive filamentous fungi, particularly in low-income health care institutions. Supplementary Information The online version contains supplementary material available at 10.1007/s40291-022-00595-1.
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Affiliation(s)
- Alexandre Mendonça
- CBMA (Centre of Molecular and Environmental Biology), Department of Biology, University of Minho, Braga, Portugal
| | - Joana Carvalho-Pereira
- CBMA (Centre of Molecular and Environmental Biology), Department of Biology, University of Minho, Braga, Portugal
| | - Ricardo Franco-Duarte
- CBMA (Centre of Molecular and Environmental Biology), Department of Biology, University of Minho, Braga, Portugal.
| | - Paula Sampaio
- CBMA (Centre of Molecular and Environmental Biology), Department of Biology, University of Minho, Braga, Portugal
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Kirchhoff L, Braun L, Schmidt D, Dittmer S, Dedy J, Herbstreit F, Stauf R, Steckel NK, Buer J, Rath PM, Steinmann J, Verhasselt HL. COVID-19-associated pulmonary aspergillosis in ICU patients in a German reference centre: phenotypic and molecular characterization of Aspergillus fumigatus isolates. Mycoses 2022; 65:458-465. [PMID: 35138651 PMCID: PMC9115305 DOI: 10.1111/myc.13430] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/05/2022] [Accepted: 02/07/2022] [Indexed: 01/08/2023]
Abstract
Background COVID‐19‐associated invasive pulmonary aspergillosis (CAPA) is associated with increased mortality. Cases of CAPA caused by azole‐resistant Aspergillus fumigatus strains have been reported. Objectives To analyse the twelve‐month CAPA prevalence in a German tertiary care hospital and to characterise clinical A. fumigatus isolates from two German hospitals by antifungal susceptibility testing and microsatellite genotyping. Patients/Methods. Retrospective observational study in critically ill adults from intensive care units with COVID‐19 from 17 February 2020 until 16 February 2021 and collection of A. fumigatus isolates from two German centres. EUCAST broth microdilution for four azole compounds and microsatellite PCR with nine markers were performed for each collected isolate (N = 27) and additional for three non‐COVID A. fumigatus isolates. Results welve‐month CAPA prevalence was 7.2% (30/414), and the rate of azole‐resistant A. fumigatus isolates from patients with CAPA was 3.7% with detection of one TR34/L98H mutation. The microsatellite analysis revealed no major clustering of the isolates. Sequential isolates mainly showed the same genotype over time. Conclusions Our findings demonstrate similar CAPA prevalence to other reports and a low azole‐resistance rate. Genotyping of A. fumigatus showed polyclonal distribution except for sequential isolates.
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Affiliation(s)
- Lisa Kirchhoff
- Institute of Medical Microbiology, University Hospital Essen, ECMM Centre of Excellence in Mycology, Germany
| | - Lukas Braun
- Institute of Medical Microbiology, University Hospital Essen, ECMM Centre of Excellence in Mycology, Germany
| | - Dirk Schmidt
- Institute of Medical Microbiology, University Hospital Essen, ECMM Centre of Excellence in Mycology, Germany
| | - Silke Dittmer
- Institute of Medical Microbiology, University Hospital Essen, ECMM Centre of Excellence in Mycology, Germany
| | - Jutta Dedy
- University Hospital Essen, Pharmacy, Germany
| | - Frank Herbstreit
- Department of Anaesthesiology and Intensive Care Medicine, University Hospital Essen, Germany
| | - Raphael Stauf
- Institute of Hospital Hygiene and Clinical Microbiology, Klinikum Dortmund gGmbH, Dortmund, Germany
| | - Nina Kristin Steckel
- Department of Bone Marrow Transplantation, West German Cancer Centre, University Hospital Essen, Essen, Germany
| | - Jan Buer
- Institute of Medical Microbiology, University Hospital Essen, ECMM Centre of Excellence in Mycology, Germany
| | - Peter-Michael Rath
- Institute of Medical Microbiology, University Hospital Essen, ECMM Centre of Excellence in Mycology, Germany
| | - Joerg Steinmann
- Institute of Medical Microbiology, University Hospital Essen, ECMM Centre of Excellence in Mycology, Germany.,Institute of Clinical Hygiene, Medical Microbiology and Infectiology, General Hospital Nürnberg, Paracelsus Medical University, Nuremberg, Germany
| | - Hedda Luise Verhasselt
- Institute of Medical Microbiology, University Hospital Essen, ECMM Centre of Excellence in Mycology, Germany
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Rogers TR, Verweij PE, Castanheira M, Dannaoui E, White PL, Arendrup MC. OUP accepted manuscript. J Antimicrob Chemother 2022; 77:2053-2073. [PMID: 35703391 PMCID: PMC9333407 DOI: 10.1093/jac/dkac161] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The increasing incidence and changing epidemiology of invasive fungal infections continue to present many challenges to their effective management. The repertoire of antifungal drugs available for treatment is still limited although there are new antifungals on the horizon. Successful treatment of invasive mycoses is dependent on a mix of pathogen-, host- and antifungal drug-related factors. Laboratories need to be adept at detection of fungal pathogens in clinical samples in order to effectively guide treatment by identifying isolates with acquired drug resistance. While there are international guidelines on how to conduct in vitro antifungal susceptibility testing, these are not performed as widely as for bacterial pathogens. Furthermore, fungi generally are recovered in cultures more slowly than bacteria, and often cannot be cultured in the laboratory. Therefore, non-culture-based methods, including molecular tests, to detect fungi in clinical specimens are increasingly important in patient management and are becoming more reliable as technology improves. Molecular methods can also be used for detection of target gene mutations or other mechanisms that predict antifungal drug resistance. This review addresses acquired antifungal drug resistance in the principal human fungal pathogens and describes known resistance mechanisms and what in-house and commercial tools are available for their detection. It is emphasized that this approach should be complementary to culture-based susceptibility testing, given the range of mutations, resistance mechanisms and target genes that may be present in clinical isolates, but may not be included in current molecular assays.
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Affiliation(s)
| | | | | | | | | | - Maiken Cavling Arendrup
- Unit of Mycology, Statens Serum Institut, Copenhagen, Denmark
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
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Mendonça A, Santos H, Franco-Duarte R, Sampaio P. Fungal infections diagnosis - Past, present and future. Res Microbiol 2022; 173:103915. [PMID: 34863883 PMCID: PMC8634697 DOI: 10.1016/j.resmic.2021.103915] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 11/19/2021] [Accepted: 11/26/2021] [Indexed: 01/07/2023]
Abstract
Despite the scientific advances observed in the recent decades and the emergence of new methodologies, the diagnosis of systemic fungal infections persists as a problematic issue. Fungal cultivation, the standard method that allows a proven diagnosis, has numerous disadvantages, as low sensitivity (only 50% of the patients present positive fungal cultures), and long growth time. These are factors that delay the patient's treatment and, consequently, lead to higher hospital costs. To improve the accuracy and quickness of fungal infections diagnosis, several new methodologies attempt to be implemented in clinical microbiology laboratories. Most of these innovative methods are independent of pathogen isolation, which means that the diagnosis goes from being considered proven to probable. In spite of the advantage of being culture-independent, the majority of the methods lack standardization. PCR-based methods are becoming more and more commonly used, which has earned them an important place in hospital laboratories. This can be perceived now, as PCR-based methodologies have proved to be an essential tool fighting against the COVID-19 pandemic. This review aims to go through the main steps of the diagnosis for systemic fungal infection, from diagnostic classifications, through methodologies considered as "gold standard", to the molecular methods currently used, and finally mentioning some of the more futuristic approaches.
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Wang F, Ge D, Wang L, Li N, Chen H, Zhang Z, Zhu W, Wang S, Liang W. Rapid and sensitive recombinase polymerase amplification combined with lateral flow strips for detecting Candida albicans. Anal Biochem 2021; 633:114428. [PMID: 34678249 DOI: 10.1016/j.ab.2021.114428] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 10/13/2021] [Accepted: 10/16/2021] [Indexed: 12/30/2022]
Abstract
Owing to modern lifestyles and increasing amounts of medical intervention, clinical infections caused by conditionally pathogenic fungi are becoming increasingly serious. Among these, Candida albicans is the most common. Therefore, the rapid and accurate detection of this pathogenic fungus is important to guiding the selection of clinical therapeutic agents. Recombinase polymerase amplification (RPA) combined with lateral flow strips (LFS) is a promising molecular detection method with the advantages of rapidity, simplicity of operation and high sensitivity. However, this simplicity brings with it the inherent and non-negligible risk of false-positive signals from primer-dimers. In this study, primer-dependent artifacts were eliminated by using probes in the RPA reaction, introducing specific base substitutions to the primer and probe sequences and analyzing and screening the formation of primer-probe complexes. These measures were rigorously tested for efficacy, leading to the creation of an improved RPA-LFS system. The standardized method enabled the specific detection of C. albicans within 25 min at 37 °C without interference. The system had a detection limit of 1 CFU per reaction without DNA purification or 102 fg genomic DNA/50 μL. The detection sensitivity was not affected by the presence of other fungal DNA. The RPA-LFS method can therefore be used to detect clinical samples, and the results are accurate and consistent in comparison with those obtained using quantitative PCR. This study provides a paradigm for eliminating the risk of false-positive primer dimers in isothermal amplification assays and establishes a simple and easy method for the detection of C. albicans.
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Affiliation(s)
- Fang Wang
- Department of Central Laboratory, the Second People's Hospital of Lianyungang City (Cancer Hospital of Lianyungang), Affiliated to Bengbu Medical College, Lianyungang, 222000, Jiangsu, China
| | - Duobao Ge
- Department of Central Laboratory, the Second People's Hospital of Lianyungang City (Cancer Hospital of Lianyungang), Affiliated to Bengbu Medical College, Lianyungang, 222000, Jiangsu, China
| | - Lei Wang
- Department of Central Laboratory, the Second People's Hospital of Lianyungang City (Cancer Hospital of Lianyungang), Affiliated to Bengbu Medical College, Lianyungang, 222000, Jiangsu, China; School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, 212018, Jiangsu, China
| | - Na Li
- Department of Central Laboratory, the Second People's Hospital of Lianyungang City (Cancer Hospital of Lianyungang), Affiliated to Bengbu Medical College, Lianyungang, 222000, Jiangsu, China
| | - Huimin Chen
- Department of Central Laboratory, the Second People's Hospital of Lianyungang City (Cancer Hospital of Lianyungang), Affiliated to Bengbu Medical College, Lianyungang, 222000, Jiangsu, China
| | - Zhexiong Zhang
- Department of Central Laboratory, the Second People's Hospital of Lianyungang City (Cancer Hospital of Lianyungang), Affiliated to Bengbu Medical College, Lianyungang, 222000, Jiangsu, China
| | - Wenjun Zhu
- Department of Central Laboratory, the Second People's Hospital of Lianyungang City (Cancer Hospital of Lianyungang), Affiliated to Bengbu Medical College, Lianyungang, 222000, Jiangsu, China
| | - Siming Wang
- Department of Central Laboratory, the Second People's Hospital of Lianyungang City (Cancer Hospital of Lianyungang), Affiliated to Bengbu Medical College, Lianyungang, 222000, Jiangsu, China.
| | - Wei Liang
- Department of Central Laboratory, the Second People's Hospital of Lianyungang City (Cancer Hospital of Lianyungang), Affiliated to Bengbu Medical College, Lianyungang, 222000, Jiangsu, China.
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Pasula S, Chandrasekar PH. Azole resistance in Aspergillus species: promising therapeutic options. Expert Opin Pharmacother 2021; 22:2071-2078. [PMID: 34129410 DOI: 10.1080/14656566.2021.1940134] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
INTRODUCTION Azoles are the first-line antifungal agents used for the treatment of Aspergillus infection. There is an increasing concern for azole resistance all over the world mainly from agricultural fungicide use. Choosing safe and effective antifungal regimens has become a challenge. AREAS COVERED Here, the authors review the epidemiology, mechanisms, and detection of azole resistance along with management options for azole-resistant Aspergillus infection, including new antifungal agents under development. EXPERT OPINION Routine global epidemiological surveillance is required to understand azole resistance prevalence. Azole-resistant Aspergillus infections are associated with high mortality. No good therapeutic options are currently available. High index of suspicion of resistance is required if a patient is not responding to 4-7 days of azole therapy, particularly in the areas of resistance. Susceptibility testing for Aspergillus is not routinely available in many parts of the world, which makes it difficult to diagnose azole resistance in Aspergillus infection. There are several new antifungal classes with novel mechanisms of action; clinical trials are ongoing.
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Affiliation(s)
- Shirisha Pasula
- Department of Internal medicine, Division of Infectious diseases, Detroit Medical Center/Wayne State University, Detroit, MI, USA
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