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Djenontin E, Debourgogne A, Mousavi B, Delhaes L, Cornet M, Valsecchi I, Adebo M, Guillot J, Botterel F, Dannaoui E. Azole resistance in Aspergillus flavus and associated fitness cost. Mycoses 2024; 67:e13766. [PMID: 39007526 DOI: 10.1111/myc.13766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 06/26/2024] [Accepted: 06/30/2024] [Indexed: 07/16/2024]
Abstract
BACKGROUND The resistance of Aspergillus flavus to the azole antifungal drugs is an emerging problem. Mutations in the molecular targets of the azole antifungals - CYP 51 A, B and C - are possible mechanisms of resistance, but data to confirm this hypothesis are scarce. In addition, the behaviour of resistant strains in vitro and in vivo is not yet understood. OBJECTIVES This study had 3 objectives. The first was to compare the sequences of CYP51 A, B and C in resistant and susceptible strains of A. flavus. The second was to look for the existence of a fitness cost associated with resistance. The third was to evaluate the activity of voriconazole and posaconazole on resistant strains in the Galleria mellonella model. METHODS The CYP51 A, B and C sequences of seven resistant strains with those of four susceptible strains are compared. Fitness costs were assessed by growing the strains in RPMI medium and testing their virulence in G. mellonella larvae. In addition, G. mellonella larvae infected with strains of A. flavus were treated with voriconazole and posaconazole. RESULTS In the CYP51A sequences, we found the A91T, C708T and A1296T nucleotide substitutions only in the resistant strains. The resistant strains showed a fitness cost with reduced in vitro growth and reduced virulence in G. mellonella. In vivo resistance to posaconazole is confirmed in a strain with the highest MIC for this antifungal agent. CONCLUSIONS These results allow to conclude that some substitutions in CYP51 genes, in particular CYP51A, contribute to resistance to azole drugs in A. flavus. The study of the relationship between drug dosage and treatment duration with resistance and the reduction of fitness costs in resistant strains is a major perspective of this study. This work could help to establish recommendations for the treatment of infections with resistant strains of A. flavus.
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Affiliation(s)
- Elie Djenontin
- Unité de Parasitologie-Mycologie, Département de Virologie, Bactériologie-Hygiène, Parasitologie-Mycologie, CHU Henri Mondor, AP-HP, Créteil, France
- UR Dynamyc UPEC, EnvA, ANSES. Faculté de Santé de Créteil, Créteil, France
| | - Anne Debourgogne
- UR7300 Stress Immunité Pathogène, Université de Lorraine, Vandoeuvre les Nancy, France
| | - Bita Mousavi
- UR Dynamyc UPEC, EnvA, ANSES. Faculté de Santé de Créteil, Créteil, France
| | - Laurence Delhaes
- CHU de Bordeaux: Laboratoire de Parasitologie-Mycologie, CNR des Aspergilloses Chroniques, INSERM U1045: Univ. Bordeaux, Bordeaux, France
| | - Muriel Cornet
- Université Grenoble Alpes, CNRS, Grenoble INP, CHU Grenoble Alpes, TIMC, Grenoble, France
| | - Isabel Valsecchi
- Unité de Parasitologie-Mycologie, Département de Virologie, Bactériologie-Hygiène, Parasitologie-Mycologie, CHU Henri Mondor, AP-HP, Créteil, France
| | - Makiath Adebo
- UR Dynamyc UPEC, EnvA, ANSES. Faculté de Santé de Créteil, Créteil, France
| | | | - Françoise Botterel
- Unité de Parasitologie-Mycologie, Département de Virologie, Bactériologie-Hygiène, Parasitologie-Mycologie, CHU Henri Mondor, AP-HP, Créteil, France
- UR Dynamyc UPEC, EnvA, ANSES. Faculté de Santé de Créteil, Créteil, France
| | - Eric Dannaoui
- Unité de Parasitologie-Mycologie, Département de Virologie, Bactériologie-Hygiène, Parasitologie-Mycologie, CHU Henri Mondor, AP-HP, Créteil, France
- Unité de Parasitologie-Mycologie, Service de Microbiologie, Hôpital Necker, AP-HP, Paris, France
- Université Paris Cité, Faculté de Médecine, Paris, France
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Vanhoffelen E, Michiels L, Brock M, Lagrou K, Reséndiz-Sharpe A, Vande Velde G. Powerful and Real-Time Quantification of Antifungal Efficacy against Triazole-Resistant and -Susceptible Aspergillus fumigatus Infections in Galleria mellonella by Longitudinal Bioluminescence Imaging. Microbiol Spectr 2023; 11:e0082523. [PMID: 37466453 PMCID: PMC10433797 DOI: 10.1128/spectrum.00825-23] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 06/27/2023] [Indexed: 07/20/2023] Open
Abstract
Aspergillus fumigatus is an environmental mold that causes life-threatening respiratory infections in immunocompromised patients. The plateaued effectiveness of antifungal therapy and the increasing prevalence of triazole-resistant isolates have led to an urgent need to optimize and expand the current treatment options. For the transition of in vitro research to in vivo models in the time- and resource-consuming preclinical drug development pipeline, Galleria mellonella larvae have been introduced as a valuable in vivo screening intermediate. Despite the high potential of this model, the current readouts of fungal infections in G. mellonella are insensitive, irreproducible, or invasive. To optimize this model, we aimed for the longitudinal quantification of the A. fumigatus burden in G. mellonella using noninvasive bioluminescence imaging (BLI). Larvae were infected with A. fumigatus strains expressing a red-shifted firefly luciferase, and the substrate dosage was optimized for the longitudinal visualization of the fungal burden without affecting larval health. The resulting photon flux was successfully validated for fungal quantification against colony forming units (CFU) analyses, which revealed an increased dynamic range from BLI detection. Comparison of BLI to survival rates and health index scores additionally revealed improved sensitivity for the early discrimination of differences in fungal burdens as early as 1 day after infection. This was confirmed by the improved detection of treatment efficacy against triazole-susceptible and -resistant strains. In conclusion, we established a refined G. mellonella aspergillosis model that enables the noninvasive real-time quantification of A. fumigatus by BLI. This model provides a quick and reproducible in vivo system for the evaluation of treatment options and is in line with 3Rs recommendations. IMPORTANCE Triazole-resistant Aspergillus fumigatus strains are rapidly emerging, and resistant infections are difficult to treat, causing mortality rates of up to 88%. The recent WHO priority list underscores A. fumigatus as one of the most critical fungal pathogens for which innovative antifungal treatment should be (urgently) prioritized. Here, we deliver a Galleria mellonella model for triazole-susceptible and -resistant A. fumigatus infections combined with a statistically powerful quantitative, longitudinal readout of the A. fumigatus burden for optimized preclinical antifungal screening. G. mellonella larvae are a convenient invertebrate model for in vivo antifungal screenings, but so far, the model has been limited by variable and insensitive observational readouts. We show that bioluminescence imaging-based fungal burden quantification outperforms these readouts in reliability, sensitivity, and time to the detection of treatment effects in both triazole-susceptible and -resistant infections and can thus lead to better translatability from in vitro antifungal screening results to in vivo confirmation in mouse and human studies.
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Affiliation(s)
- Eliane Vanhoffelen
- Department of Imaging and Pathology, Biomedical MRI Unit/MoSAIC, KU Leuven, Leuven, Belgium
| | - Lauren Michiels
- Department of Imaging and Pathology, Biomedical MRI Unit/MoSAIC, KU Leuven, Leuven, Belgium
| | - Matthias Brock
- School of Life Sciences, Fungal Biology Group, University of Nottingham, Nottingham, United Kingdom
| | - Katrien Lagrou
- Department of Microbiology, Immunology and Transplantation, Laboratory of Clinical Bacteriology and Mycology, KU Leuven, Leuven, Belgium
- Department of Laboratory Medicine, National Reference Center for Mycosis, University Hospitals Leuven, Leuven, Belgium
| | | | - Greetje Vande Velde
- Department of Imaging and Pathology, Biomedical MRI Unit/MoSAIC, KU Leuven, Leuven, Belgium
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Scott J, Valero C, Mato-López Á, Donaldson IJ, Roldán A, Chown H, Van Rhijn N, Lobo-Vega R, Gago S, Furukawa T, Morogovsky A, Ben Ami R, Bowyer P, Osherov N, Fontaine T, Goldman GH, Mellado E, Bromley M, Amich J. Aspergillus fumigatus Can Display Persistence to the Fungicidal Drug Voriconazole. Microbiol Spectr 2023; 11:e0477022. [PMID: 36912663 PMCID: PMC10100717 DOI: 10.1128/spectrum.04770-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 02/12/2023] [Indexed: 03/14/2023] Open
Abstract
Aspergillus fumigatus is a filamentous fungus that can infect the lungs of patients with immunosuppression and/or underlying lung diseases. The mortality associated with chronic and invasive aspergillosis infections remain very high, despite availability of antifungal treatments. In the last decade, there has been a worrisome emergence and spread of resistance to the first-line antifungals, the azoles. The mortality caused by resistant isolates is even higher, and patient management is complicated as the therapeutic options are reduced. Nevertheless, treatment failure is also common in patients infected with azole-susceptible isolates, which can be due to several non-mutually exclusive reasons, such as poor drug absorption. In addition, the phenomena of tolerance or persistence, where susceptible pathogens can survive the action of an antimicrobial for extended periods, have been associated with treatment failure in bacterial infections, and their occurrence in fungal infections already proposed. Here, we demonstrate that some isolates of A. fumigatus display persistence to voriconazole. A subpopulation of the persister isolates can survive for extended periods and even grow at low rates in the presence of supra-MIC of voriconazole and seemingly other azoles. Persistence cannot be eradicated with adjuvant drugs or antifungal combinations and seemed to reduce the efficacy of treatment for certain individuals in a Galleria mellonella model of infection. Furthermore, persistence implies a distinct transcriptional profile, demonstrating that it is an active response. We propose that azole persistence might be a relevant and underestimated factor that could influence the outcome of infection in human aspergillosis. IMPORTANCE The phenomena of antibacterial tolerance and persistence, where pathogenic microbes can survive for extended periods in the presence of cidal drug concentrations, have received significant attention in the last decade. Several mechanisms of action have been elucidated, and their relevance for treatment failure in bacterial infections demonstrated. In contrast, our knowledge of antifungal tolerance and, in particular, persistence is still very limited. In this study, we have characterized the response of the prominent fungal pathogen Aspergillus fumigatus to the first-line therapy antifungal voriconazole. We comprehensively show that some isolates display persistence to this fungicidal antifungal and propose various potential mechanisms of action. In addition, using an alternative model of infection, we provide initial evidence to suggest that persistence may cause treatment failure in some individuals. Therefore, we propose that azole persistence is an important factor to consider and further investigate in A. fumigatus.
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Affiliation(s)
- Jennifer Scott
- Manchester Fungal Infection Group, Division of Evolution, Infection, and Genomics, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Clara Valero
- Manchester Fungal Infection Group, Division of Evolution, Infection, and Genomics, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Álvaro Mato-López
- Mycology Reference Laboratory (Laboratorio de Referencia e Investigación en Micología [LRIM]), National Centre for Microbiology, Instituto de Salud Carlos III (ISCIII), Majadahonda, Madrid, Spain
| | - Ian J. Donaldson
- Bioinformatics Core Facility, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Alejandra Roldán
- Mycology Reference Laboratory (Laboratorio de Referencia e Investigación en Micología [LRIM]), National Centre for Microbiology, Instituto de Salud Carlos III (ISCIII), Majadahonda, Madrid, Spain
| | - Harry Chown
- Manchester Fungal Infection Group, Division of Evolution, Infection, and Genomics, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Norman Van Rhijn
- Manchester Fungal Infection Group, Division of Evolution, Infection, and Genomics, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Rebeca Lobo-Vega
- Mycology Reference Laboratory (Laboratorio de Referencia e Investigación en Micología [LRIM]), National Centre for Microbiology, Instituto de Salud Carlos III (ISCIII), Majadahonda, Madrid, Spain
| | - Sara Gago
- Manchester Fungal Infection Group, Division of Evolution, Infection, and Genomics, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Takanori Furukawa
- Manchester Fungal Infection Group, Division of Evolution, Infection, and Genomics, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Alma Morogovsky
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine Ramat-Aviv, Tel-Aviv, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ronen Ben Ami
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine Ramat-Aviv, Tel-Aviv, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Paul Bowyer
- Manchester Fungal Infection Group, Division of Evolution, Infection, and Genomics, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Nir Osherov
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine Ramat-Aviv, Tel-Aviv, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Thierry Fontaine
- Institut Pasteur, Université de Paris, INRAE, USC2019, Unité Biologie et Pathogénicité Fongiques, Paris, France
| | - Gustavo H. Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Emilia Mellado
- Mycology Reference Laboratory (Laboratorio de Referencia e Investigación en Micología [LRIM]), National Centre for Microbiology, Instituto de Salud Carlos III (ISCIII), Majadahonda, Madrid, Spain
- CiberInfec ISCIII, CIBER en Enfermedades Infecciosas, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Michael Bromley
- Manchester Fungal Infection Group, Division of Evolution, Infection, and Genomics, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Jorge Amich
- Manchester Fungal Infection Group, Division of Evolution, Infection, and Genomics, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
- Mycology Reference Laboratory (Laboratorio de Referencia e Investigación en Micología [LRIM]), National Centre for Microbiology, Instituto de Salud Carlos III (ISCIII), Majadahonda, Madrid, Spain
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Jemel S, Raveloarisaona Y, Bidaud AL, Djenontin E, Kallel A, Guillot J, Kallel K, Botterel F, Dannaoui E. In vitro and in vivo evaluation of antifungal combinations against azole-resistant Aspergillus fumigatus isolates. Front Cell Infect Microbiol 2023; 12:1038342. [PMID: 36733850 PMCID: PMC9887171 DOI: 10.3389/fcimb.2022.1038342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 11/25/2022] [Indexed: 01/19/2023] Open
Abstract
Azole resistance in Aspergillus fumigatus (Af) has become a widespread threat and a major concern for optimal management of patients with invasive aspergillosis (IA). Combination of echinocandins with azoles is an attractive alternative option for the treatment of IA due to azole-resistant Af strains. The aim of this study was to evaluate the in vitro and in vivo combination of caspofungin (CAS) with either voriconazole (VRZ) or posaconazole (PSZ). In vitro interactions were assessed by two methods, and an animal model of IA in Galleria mellonella was used for in vivo evaluation. Assessment of efficacy was based on larvae mortality. Groups of 10 larvae were infected by 3 clinical strains of Af (azole susceptible, AfS; PSZ resistant, AfR1; VRZ and PSZ resistant strain, AfR2). In vitro, combination of CAS and azoles was indifferent against AfS, and AfR2, and a synergy was found for AfR1. When compared to VRZ monotherapy, the combination of VRZ at 4 µg/larva with CAS at 4 µg/larva improved survival of AfR2-infected larvae (p=0.0066). Combination of PSZ at 4µg/larva with CAS at 4 µg/larva improved survival of AfR1-infected larvae compared to CAS (p=0.0002) and PSZ (0.0024) monotherapy. Antagonism was never observed. In conclusion, the combination of caspofungin with azoles is a promising alternative for the treatment of azole resistant strains of Af.
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Affiliation(s)
- Sana Jemel
- Université Paris Est Créteil, Dynamyc, Créteil, France
- Université Tunis EL Manar, Faculté de médecine de Tunis, Tunis, Tunisie
- UR17SP03, Centre Hospitalo-Universitaire La Rabta, Jabbari, Tunis, Tunisie
| | - Yannick Raveloarisaona
- Unité de Parasitologie-Mycologie, Service de Microbiologie, Assistance Publique - Hôpitaux de Paris (APHP), Hôpital Européen Georges Pompidou, Paris, France
- Université de Paris-Cité, Faculté Médecine, Paris, France
| | - Anne-Laure Bidaud
- Unité de Parasitologie-Mycologie, Service de Microbiologie, Assistance Publique - Hôpitaux de Paris (APHP), Hôpital Européen Georges Pompidou, Paris, France
- Université de Paris-Cité, Faculté Médecine, Paris, France
| | - Elie Djenontin
- Université Paris Est Créteil, Dynamyc, Créteil, France
- Unité de Parasitologie-Mycologie, Service de Microbiologie, Assistance Publique - Hôpitaux de Paris (APHP), Hôpital Européen Georges Pompidou, Paris, France
| | - Aicha Kallel
- Université Tunis EL Manar, Faculté de médecine de Tunis, Tunis, Tunisie
- UR17SP03, Centre Hospitalo-Universitaire La Rabta, Jabbari, Tunis, Tunisie
| | - Jacques Guillot
- Dermatology-Parasitology-Mycology, Oniris, Nantes, France
- Univ. Angers, Univ. Brest, IRF, SFR ICAT, Angers, France
| | - Kalthoum Kallel
- Université Tunis EL Manar, Faculté de médecine de Tunis, Tunis, Tunisie
- UR17SP03, Centre Hospitalo-Universitaire La Rabta, Jabbari, Tunis, Tunisie
| | | | - Eric Dannaoui
- Université Paris Est Créteil, Dynamyc, Créteil, France
- Unité de Parasitologie-Mycologie, Service de Microbiologie, Assistance Publique - Hôpitaux de Paris (APHP), Hôpital Européen Georges Pompidou, Paris, France
- Université de Paris-Cité, Faculté Médecine, Paris, France
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Li Y, Peng Y, Zhang N, Liu H, Mao J, Yan Y, Wang S, Yang G, Liu Y, Li J, Huang X. Assessing the Emergence of Resistance in vitro and Invivo: Linezolid Combined with Fosfomycin Against Fosfomycin-Sensitive and Resistant Enterococcus. Infect Drug Resist 2022; 15:4995-5010. [PMID: 36065277 PMCID: PMC9440711 DOI: 10.2147/idr.s377848] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 08/20/2022] [Indexed: 11/23/2022] Open
Affiliation(s)
- Yaowen Li
- Department of Basic and Clinical Pharmacology, School of Pharmacy, Anhui Medical University, Hefei, People’s Republic of China
- Anhui Province Key Laboratory of Major Autoimmune Diseases, School of Pharmacy, Anhui Institute of Innovative Drugs, Anhui Medical University, Hefei, People’s Republic of China
| | - Yu Peng
- Department of Basic and Clinical Pharmacology, School of Pharmacy, Anhui Medical University, Hefei, People’s Republic of China
- Anhui Province Key Laboratory of Major Autoimmune Diseases, School of Pharmacy, Anhui Institute of Innovative Drugs, Anhui Medical University, Hefei, People’s Republic of China
| | - Na Zhang
- Department of Basic and Clinical Pharmacology, School of Pharmacy, Anhui Medical University, Hefei, People’s Republic of China
- Anhui Province Key Laboratory of Major Autoimmune Diseases, School of Pharmacy, Anhui Institute of Innovative Drugs, Anhui Medical University, Hefei, People’s Republic of China
| | - Huiping Liu
- Department of Basic and Clinical Pharmacology, School of Pharmacy, Anhui Medical University, Hefei, People’s Republic of China
- Anhui Province Key Laboratory of Major Autoimmune Diseases, School of Pharmacy, Anhui Institute of Innovative Drugs, Anhui Medical University, Hefei, People’s Republic of China
| | - Jun Mao
- Department of Basic and Clinical Pharmacology, School of Pharmacy, Anhui Medical University, Hefei, People’s Republic of China
- Anhui Province Key Laboratory of Major Autoimmune Diseases, School of Pharmacy, Anhui Institute of Innovative Drugs, Anhui Medical University, Hefei, People’s Republic of China
| | - Yisong Yan
- Department of Pharmacy, Anhui College of Traditional Chinese Medicine, Wuhu, Anhui, People’s Republic of China
| | - Shuaishuai Wang
- Department of Basic and Clinical Pharmacology, School of Pharmacy, Anhui Medical University, Hefei, People’s Republic of China
- Anhui Province Key Laboratory of Major Autoimmune Diseases, School of Pharmacy, Anhui Institute of Innovative Drugs, Anhui Medical University, Hefei, People’s Republic of China
| | - Guang Yang
- Department of Pharmacy, The Third People’s Hospital of Tongling, Tongling, Anhui, People’s Republic of China
| | - Yanyan Liu
- Department of Infectious Diseases, The First Affiliated Hospital of Anhui Medical University, Hefei, People’s Republic of China
| | - Jiabin Li
- Department of Infectious Diseases, The First Affiliated Hospital of Anhui Medical University, Hefei, People’s Republic of China
| | - Xiaohui Huang
- Department of Basic and Clinical Pharmacology, School of Pharmacy, Anhui Medical University, Hefei, People’s Republic of China
- Anhui Province Key Laboratory of Major Autoimmune Diseases, School of Pharmacy, Anhui Institute of Innovative Drugs, Anhui Medical University, Hefei, People’s Republic of China
- Correspondence: Xiaohui Huang, Department of Basic and Clinical Pharmacology, School of Pharmacy, Anhui Medical University, Meishan Road 81#, Hefei, Anhui, 230032, People’s Republic of China, Tel +86 138 5518 3138, Email
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Curtis A, Binder U, Kavanagh K. Galleria mellonella Larvae as a Model for Investigating Fungal-Host Interactions. FRONTIERS IN FUNGAL BIOLOGY 2022; 3:893494. [PMID: 37746216 PMCID: PMC10512315 DOI: 10.3389/ffunb.2022.893494] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 04/01/2022] [Indexed: 09/26/2023]
Abstract
Galleria mellonella larvae have become a widely accepted and utilised infection model due to the functional homology displayed between their immune response to infection and that observed in the mammalian innate immune response. Due to these similarities, comparable results to murine studies can be obtained using G. mellonella larvae in assessing the virulence of fungal pathogens and the in vivo toxicity or efficacy of anti-fungal agents. This coupled with their low cost, rapid generation of results, and lack of ethical/legal considerations make this model very attractive for analysis of host-pathogen interactions. The larvae of G. mellonella have successfully been utilised to analyse various fungal virulence factors including toxin and enzyme production in vivo providing in depth analysis of the processes involved in the establishment and progression of fungal pathogens (e.g., Candida spps, Aspergillus spp., Madurella mycetomatis, Mucormycetes, and Cryptococcus neoformans). A variety of experimental endpoints can be employed including analysis of fungal burdens, alterations in haemocyte density or sub-populations, melanisation, and characterisation of infection progression using proteomic, histological or imaging techniques. Proteomic analysis can provide insights into both sides of the host-pathogen interaction with each respective proteome being analysed independently following infection and extraction of haemolymph from the larvae. G. mellonella can also be employed for assessing the efficacy and toxicity of antifungal strategies at concentrations comparable to those used in mammals allowing for early stage investigation of novel compounds and combinations of established therapeutic agents. These numerous applications validate the model for examination of fungal infection and development of therapeutic approaches in vivo in compliance with the need to reduce animal models in biological research.
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Affiliation(s)
- Aaron Curtis
- Department of Biology, Maynooth University, Maynooth, Ireland
| | - Ulrike Binder
- Institute of Hygiene and Medical Microbiology, Medical University Innsbruck, Innsbruck, Austria
| | - Kevin Kavanagh
- Department of Biology, Maynooth University, Maynooth, Ireland
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