1
|
Howard A, Hope W. Assessment of Antifungal Pharmacodynamics. J Fungi (Basel) 2023; 9:jof9020192. [PMID: 36836307 PMCID: PMC9960731 DOI: 10.3390/jof9020192] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/19/2023] [Accepted: 01/25/2023] [Indexed: 02/05/2023] Open
Abstract
Pharmacokinetic-pharmacodynamic (PK-PD) analysis is of central importance to the progress of an antifungal agent into clinical use. It is crucial to ensure that preclinical studies give the best possible prediction of the way drugs are likely to behave in a clinical setting. This review details the last 30 years of progress in terms of disease model design, efficacy outcome selection and translational modelling in antifungal PK-PD studies. The principles of how PK-PD parameters inform current clinical practice are also discussed, including a review of how these apply to existing and novel agents.
Collapse
|
2
|
Long-Term Kinetics of Serum Galactomannan during Treatment of Complicated Invasive Pulmonary Aspergillosis. J Fungi (Basel) 2023; 9:jof9020157. [PMID: 36836274 PMCID: PMC9965572 DOI: 10.3390/jof9020157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Revised: 01/19/2023] [Accepted: 01/19/2023] [Indexed: 01/26/2023] Open
Abstract
Several studies have evaluated the serum galactomannan (GM) antigen assay in pediatric patients, and there is convincing evidence for its usefulness as a diagnostic tool for invasive Aspergillus infections in patients with acute leukemias or post allogeneic hematopoietic cell transplantation (HCT). Less is known about the utility of the assay in monitoring responses to treatment in patients with established invasive aspergillosis (IA). Here, we present the long-term kinetics of serum galactomannan in two severely immunocompromised adolescents with invasive pulmonary aspergillosis (IPA) who were cured after complicated clinical courses. We also review the utility of the GM antigen assay in serum as a prognostic tool around the time of diagnosis of IA and as a biomarker to monitor disease activity in patients with established IA and assess responses to systemic antifungal therapy.
Collapse
|
3
|
Ullmann I, Aregger A, Leib SL, Zimmerli S. Caspofungin Cerebral Penetration and Therapeutic Efficacy in Experimental Cerebral Aspergillosis. Microbiol Spectr 2022; 10:e0275321. [PMID: 35435756 PMCID: PMC9241807 DOI: 10.1128/spectrum.02753-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Accepted: 04/06/2022] [Indexed: 12/05/2022] Open
Abstract
Despite best available therapy, cerebral aspergillosis is an often-lethal complication of disseminated aspergillosis. There is an urgent need to expand the currently limited therapeutic options. In this study, we assessed cerebral drug exposure and efficacy of caspofungin (CAS) using a lethal infant rat model of cerebral aspergillosis. Eleven-day-old Wistar rats were infected by intracisternal injection of Aspergillus fumigatus conidia. Treatment started after 22 h and was continued for 10 days. Regimens were CAS 1 mg/kg/day intraperitoneally (i.p.), liposomal amphotericin B (L-AmB) 5 mg/kg/day i.p., and both drugs combined at the same dose i.p. Infected controls were given NaCl 0.85% i.p. Primary endpoints assessed were survival, cerebral fungal burden, galactomannan index, and drug concentrations in brain homogenate at 2, 3, 5, and 11 days after infection. Compared to those of controls (4.4 ± 2.7 days), survival times were increased by treatment with CAS alone (10.3 ± 1.7 days; P < 0.0001) and CAS combined with L-AmB (9.3 ± 2.8 days; P < 0.0001). In contrast, survival time of L-AmB-treated animals (4.3 ± 3.1 days) was not different from that of controls. Cerebral fungal burden and galactomannan index declined in all animals over time, without significant differences between controls and treated animals. CAS trough levels in brain tissue were between 0.84 and 1.4 μg/g, concentrations we show to be associated with efficacy. AmB trough levels in brain tissue were higher than the MIC of the A. fumigatus isolate. In summary, CAS concentrations in brain tissue suggest it may be therapeutically relevant and it significantly improved survival in this lethal model of cerebral aspergillosis in nonneutropenic rats. The clinical efficacy of CAS treatment for cerebral aspergillosis merits further study. IMPORTANCE Treatment options for cerebral aspergillosis, an often-lethal disease, are limited. The echinocandins (caspofungin is one of them) are not recommended treatment because their brain tissue penetration is often considered insufficient. In a nursing rat model of cerebral aspergillosis that mimics human disease, we found potentially therapeutically relevant concentrations of caspofungin in brain tissue and prolonged survival of caspofungin-treated animals. The efficacy of caspofungin in the treatment of cerebral aspergillosis documented here, if confirmed in other animal models (especially immunosuppressed murine models) and by using additional Aspergillus isolates across a range of CAS minimal effective concentrations (MECs), would suggest that caspofungin merits further study as a treatment option for patients suffering from aspergillosis disseminated to the brain.
Collapse
Affiliation(s)
- Irina Ullmann
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
- Clinic of General Internal and Emergency Medicine, Citizens Hospital Solothurn, Solothurn, Switzerland
| | - Andrea Aregger
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
- Center for Intensive Care Medicine, Lucerne Cantonal Hospital, Lucerne, Switzerland
| | - Stephen L. Leib
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Stefan Zimmerli
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
- Department of Infectious Diseases, Bern University Hospital, University of Bern, Bern, Switzerland
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
Ukai Y, Nishiyama Y, Okazaki K, Maki H, Naito A. A highly sensitive and specific method to evaluate viable fungal burden of Aspergillus fumigatus in mice by RT-qPCR for 18S ribosomal RNA. J Microbiol Methods 2021; 184:106214. [PMID: 33811935 DOI: 10.1016/j.mimet.2021.106214] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 03/11/2021] [Accepted: 03/29/2021] [Indexed: 10/21/2022]
Abstract
Potent fungicidal activity is one of the key factors of antifungals to overcome invasive pulmonary aspergillosis (IPA). To date, quantification of Aspergillus DNA in the lungs and galactomannan (GM) in serum or bronchoalveolar lavage fluid have been developed as general methods for measuring fungal burden in IPA animal models. However, GM quantification is not supposed to be a suitable method for precise evaluation of the fungicidal effects of antifungals, because killed Aspergillus hyphae can release GM for a certain period until they are eliminated by the host. Therefore, in terms of detecting viable fungal burden of Aspergillus, quantification of Aspergillus DNA has been thought to be a suitable method. Here, to obtain a method with much higher sensitivity, we applied reverse transcription quantitative PCR (RT-qPCR) for A. fumigatus 18S ribosomal RNA to measure the viable fungal burden in murine IPA models. Prior to in vivo tests, we confirmed that the sensitivity of 18S rRNA was nearly 50-fold higher than that of 18S ribosomal DNA in vitro. This highly sensitive method made it possible to evaluate the fungicidal effects of antifungals in a low-inoculation murine IPA model. In this model, single administrations of higher doses of voriconazole and posaconazole, which have fungicidal activity, were able to display fungicidal effects with ≥1 log10 reductions by 18S rRNA quantification, whereas significant reductions in serum GM were not observed. These results suggest that 18S rRNA quantification is a powerful tool for screening novel antifungals with potent fungicidal activity only after a single administration.
Collapse
Affiliation(s)
- Yuuta Ukai
- Laboratory for Drug Discovery and Disease Research, Shionogi & Co., Ltd., Osaka, Japan; Research Area for Anti-infectious Drug Efficacy Evaluation, Shionogi TechnoAdvance Research Co., Ltd., Osaka, Japan.
| | - Yuri Nishiyama
- Laboratory for Drug Discovery and Disease Research, Shionogi & Co., Ltd., Osaka, Japan
| | - Kenichi Okazaki
- Laboratory for Drug Discovery and Disease Research, Shionogi & Co., Ltd., Osaka, Japan
| | - Hideki Maki
- Laboratory for Drug Discovery and Disease Research, Shionogi & Co., Ltd., Osaka, Japan
| | - Akira Naito
- Laboratory for Drug Discovery and Disease Research, Shionogi & Co., Ltd., Osaka, Japan
| |
Collapse
|
6
|
Modeling Invasive Aspergillosis: How Close Are Predicted Antifungal Targets? J Fungi (Basel) 2020; 6:jof6040198. [PMID: 33007839 PMCID: PMC7712059 DOI: 10.3390/jof6040198] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/23/2020] [Accepted: 09/25/2020] [Indexed: 02/06/2023] Open
Abstract
Animal model systems are a critical component of the process of discovery and development of new antifungal agents for treatment and prevention of invasive aspergillosis. The persistently neutropenic rabbit model of invasive pulmonary aspergillosis (IPA) has been a highly predictive system in identifying new antifungal agents for treatment and prevention of this frequently lethal infection. Since its initial development, the persistently neutropenic rabbit model of IPA has established a strong preclinical foundation for dosages, drug disposition, pharmacokinetics, safety, tolerability, and efficacy for deoxycholate amphotericin B, liposomal amphotericin B, amphotericin B lipid complex, amphotericin B colloidal dispersion, caspofungin, micafungin, anidulafungin, voriconazole, posaconazole, isavuconazole, and ibrexafungerp in treatment of patients with invasive aspergillosis. The findings of combination therapy with a mould-active triazole and an echinocandin in this rabbit model also predicted the outcome of the clinical trial for voriconazole plus anidulafungin for treatment of IPA. The plasma pharmacokinetic parameters and tissue disposition for most antifungal agents approximate those of humans in persistently neutropenic rabbits. Safety, particularly nephrotoxicity, has also been highly predictive in the rabbit model, as exemplified by the differential glomerular filtration rates observed in animals treated with deoxycholate amphotericin B, liposomal amphotericin B, amphotericin B lipid complex, and amphotericin B colloidal dispersion. A panel of validated outcome variables measures therapeutic outcome in the rabbit model: residual fungal burden, markers of organism-mediated pulmonary injury (lung weights and infarct scores), survival, and serum biomarkers. In selected antifungal studies, thoracic computerized tomography (CT) is also used with diagnostic imaging algorithms to measure therapeutic response of pulmonary infiltrates, which exhibit characteristic radiographic patterns, including nodules and halo signs. Further strengthening the predictive properties of the model, therapeutic response to successfully developed antifungal agents for treatment of IPA has been demonstrated over the past two decades by biomarkers of serum galactomannan and (1→3)-β-D-glucan with patterns of resolution, that closely mirror those documented responses in patients with IPA. The decision to move from laboratory to clinical trials should be predicated upon a portfolio of complementary and mutually validating preclinical laboratory animal models studies. Other model systems, including those in mice, rats, and guinea pigs, are also valuable tools in developing clinical protocols. Meticulous preclinical investigation of a candidate antifungal compound in a robust series of complementary laboratory animal models will optimize study design, de-risk clinical trials, and ensure tangible benefit to our most vulnerable immunocompromised patients with invasive aspergillosis.
Collapse
|
7
|
Caspofungin induces the release of Ca 2+ ions from internal stores by activating ryanodine receptor-dependent pathways in human tracheal epithelial cells. Sci Rep 2020; 10:11723. [PMID: 32678179 PMCID: PMC7367263 DOI: 10.1038/s41598-020-68626-7] [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: 07/25/2019] [Accepted: 06/25/2020] [Indexed: 11/09/2022] Open
Abstract
The antimycotic drug caspofungin is known to alter the cell function of cardiomyocytes and the cilia-bearing cells of the tracheal epithelium. The objective of this study was to investigate the homeostasis of intracellular Ca2+ concentration ([Ca2+]i) after exposure to caspofungin in isolated human tracheal epithelial cells. The [Ca2+]i was measured using the ratiometric fluoroprobe FURA-2 AM. We recorded two groups of epithelial cells with distinct responses to caspofungin exposure, which demonstrated either a rapid transient rise in [Ca2+]i or a sustained elevation of [Ca2+]i. Both patterns of Ca2+ kinetics were still observed when an influx of transmembraneous Ca2+ ions was pharmacologically inhibited. Furthermore, in extracellular buffer solutions without Ca2+ ions, caspofungin exposure still evoked this characteristic rise in [Ca2+]i. To shed light on the origin of the Ca2+ ions responsible for the elevation in [Ca2+]i we investigated the possible intracellular storage of Ca2+ ions. The depletion of mitochondrial Ca2+ stores using 25 µM 2,4-dinitrophenol (DNP) did not prevent the caspofungin-induced rise in [Ca2+]i, which was rapid and transient. However, the application of caffeine (30 mM) to discharge Ca2+ ions that were presumably stored in the endoplasmic reticulum (ER) prior to caspofungin exposure completely inhibited the caspofungin-induced changes in [Ca2+]i levels. When the ER-bound IP3 receptors were blocked by 2-APB (40 µM), we observed a delayed transient rise in [Ca2+]i as a response to the caspofungin. Inhibition of the ryanodine receptors (RyR) using 40 µM ryanodine completely prevented the caspofungin-induced elevation of [Ca2+]i. In summary, caspofungin has been shown to trigger an increase in [Ca2+]i independent from extracellular Ca2+ ions by liberating the Ca2+ ions stored in the ER, mainly via a RyR pathway.
Collapse
|
8
|
Stevens VM, Mueller SW, Reynolds PM, MacLaren R, Kiser TH. Extrapolating Antifungal Animal Data to Humans - Is it reliable? CURRENT FUNGAL INFECTION REPORTS 2020; 14:50-62. [PMID: 32201545 PMCID: PMC7083583 DOI: 10.1007/s12281-020-00370-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
PURPOSE OF REVIEW This article aimed to review animal models of antifungals and identifies human literature to assess if the extrapolation of results is reliable. RECENT FINDINGS Animal studies have helped identify AUC/MIC targets for new drugs and formulations such as isavuconazole and delayed release posaconazole that have translated to successful outcomes in humans. Models have also been influential in the identification of possible combination therapies for the treatment of aspergillosis, such as voriconazole and echinocandins. However, challenges are endured with animal models when it comes to replicating the pharmacokinetics of humans which has been exemplified with the newest itraconazole formulation. Additionally, animal models have displayed a survival benefit with the use of iron chelators and amphotericin for mucormycosis which was not demonstrated in humans. SUMMARY Animal models have been a staple in the development and optimization of antifungal agents. They afford the ability to investigate uncommon diseases, such as invasive fungal infections, that would otherwise take years and many resources to complete. Although there are many benefits of animal models there are also shortcomings. This is why the reliability of extrapolating data from animal models to humans is often scrutinized.
Collapse
Affiliation(s)
- Victoria M Stevens
- Department of Clinical Pharmacy, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, 12850 East Montview Boulevard, Mail Stop C238, Aurora, CO 80045, USA
| | - Scott W Mueller
- Department of Clinical Pharmacy, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, 12850 East Montview Boulevard, Mail Stop C238, Aurora, CO 80045, USA
| | - Paul M Reynolds
- Department of Clinical Pharmacy, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, 12850 East Montview Boulevard, Mail Stop C238, Aurora, CO 80045, USA
| | - Robert MacLaren
- Department of Clinical Pharmacy, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, 12850 East Montview Boulevard, Mail Stop C238, Aurora, CO 80045, USA
| | - Tyree H Kiser
- Department of Clinical Pharmacy, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, 12850 East Montview Boulevard, Mail Stop C238, Aurora, CO 80045, USA
| |
Collapse
|
9
|
Mercier T, Wera J, Chai LYA, Lagrou K, Maertens J. A Mortality Prediction Rule for Hematology Patients with Invasive Aspergillosis Based on Serum Galactomannan Kinetics. J Clin Med 2020; 9:jcm9020610. [PMID: 32102465 PMCID: PMC7073547 DOI: 10.3390/jcm9020610] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 02/11/2020] [Accepted: 02/19/2020] [Indexed: 12/16/2022] Open
Abstract
In invasive aspergillosis (IA), an early and adequate assessment of the response to the initial antifungal therapy remains problematic. We retrospectively analyzed 206 hematology patients with proven or probable IA, and collected serial serum galactomannan (sGM) values and survival status through week 6 and week 12. We created a model for survival at week 6 based on the sGM taken at baseline and on early sGM kinetics. This resulted in a rule predicting that patients with a baseline sGM index >1.4, who failed to lower that index to <0.5 after one week, had a mortality rate of 48.1% at week 6. Conversely, patients presenting with a baseline sGM index ≤1.4 that obtained a negative sGM (<0.5) after one week, had a mortality that was almost five times lower at only 10.1% by week 6. These findings were confirmed in an external cohort from an independent prospective study. In conclusion, sGM kinetics correlate well with treatment outcomes in hematology patients with IA. We present a rule which is easy to use at the bedside and has good accuracy in predicting week 6 survival.
Collapse
Affiliation(s)
- Toine Mercier
- KU Leuven, Department of Microbiology, Immunology and Transplantation, 3000 Leuven, Belgium; (K.L.); (J.M.)
- Department of Hematology, University Hospitals Leuven, 3000 Leuven, Belgium;
- Correspondence:
| | - Joachim Wera
- Department of Hematology, University Hospitals Leuven, 3000 Leuven, Belgium;
| | - Louis Y. A. Chai
- Division of Infectious Diseases, University Medicine Cluster, National University Health System, Singapore and Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119074, Singapore;
| | - Katrien Lagrou
- KU Leuven, Department of Microbiology, Immunology and Transplantation, 3000 Leuven, Belgium; (K.L.); (J.M.)
- Department of Laboratory Medicine and National Reference Center for Mycosis, University Hospitals Leuven, 3000 Leuven, Belgium
| | - Johan Maertens
- KU Leuven, Department of Microbiology, Immunology and Transplantation, 3000 Leuven, Belgium; (K.L.); (J.M.)
- Department of Hematology, University Hospitals Leuven, 3000 Leuven, Belgium;
| |
Collapse
|
10
|
Oshiro KGN, Rodrigues G, Monges BED, Cardoso MH, Franco OL. Bioactive Peptides Against Fungal Biofilms. Front Microbiol 2019; 10:2169. [PMID: 31681179 PMCID: PMC6797862 DOI: 10.3389/fmicb.2019.02169] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 09/04/2019] [Indexed: 12/20/2022] Open
Abstract
Infections caused by invasive fungal biofilms have been widely associated with high morbidity and mortality rates, mainly due to the advent of antibiotic resistance. Moreover, fungal biofilms impose an additional challenge, leading to multidrug resistance. This fact, along with the contamination of medical devices and the limited number of effective antifungal agents available on the market, demonstrates the importance of finding novel drug candidates targeting pathogenic fungal cells and biofilms. In this context, an alternative strategy is the use of antifungal peptides (AFPs) against fungal biofilms. AFPs are considered a group of bioactive molecules with broad-spectrum activities and multiple mechanisms of action that have been widely used as template molecules for drug design strategies aiming at greater specificity and biological efficacy. Among the AFP classes most studied in the context of fungal biofilms, defensins, cathelicidins and histatins have been described. AFPs can also act by preventing the formation of fungal biofilms and eradicating preformed biofilms through mechanisms associated with cell wall perturbation, inhibition of planktonic fungal cells’ adhesion onto surfaces, gene regulation and generation of reactive oxygen species (ROS). Thus, considering the critical scenario imposed by fungal biofilms and associated infections and the application of AFPs as a possible treatment, this review will focus on the most effective AFPs described to date, with a core focus on antibiofilm peptides, as well as their efficacy in vivo, application on surfaces and proposed mechanisms of action.
Collapse
Affiliation(s)
- Karen G N Oshiro
- Programa de Pós-Graduação em Patologia Molecular, Faculdade de Medicina, Universidade de Brasília, Brasília, Brazil.,S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande, Brazil
| | - Gisele Rodrigues
- Centro de Análises Proteômicas e Bioquímicas, Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, Brazil
| | - Bruna Estéfani D Monges
- S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande, Brazil
| | - Marlon Henrique Cardoso
- S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande, Brazil.,Centro de Análises Proteômicas e Bioquímicas, Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, Brazil
| | - Octávio Luiz Franco
- Programa de Pós-Graduação em Patologia Molecular, Faculdade de Medicina, Universidade de Brasília, Brasília, Brazil.,S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande, Brazil.,Centro de Análises Proteômicas e Bioquímicas, Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, Brazil
| |
Collapse
|
11
|
Echinocandins for the Treatment of Invasive Aspergillosis: from Laboratory to Bedside. Antimicrob Agents Chemother 2019; 63:AAC.00399-19. [PMID: 31138565 DOI: 10.1128/aac.00399-19] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Echinocandins (caspofungin, micafungin, anidulafungin), targeting β-1,3-glucan synthesis of the cell wall, represent one of the three currently available antifungal drug classes for the treatment of invasive fungal infections. Despite their limited antifungal activity against Aspergillus spp., echinocandins are considered an alternative option for the treatment of invasive aspergillosis (IA). This drug class exhibits several advantages, such as excellent tolerability and its potential for synergistic interactions with some other antifungals. The objective of this review is to discuss the in vitro and clinical efficacy of echinocandins against Aspergillus spp., considering the complex interactions between the drug, the mold, and the host. The antifungal effect of echinocandins is not limited to direct inhibition of hyphal growth but also induces an immunomodulatory effect on the host's response. Moreover, Aspergillus spp. have developed important adaptive mechanisms of tolerance to survive and overcome the action of echinocandins, such as paradoxical growth at increased concentrations. This stress response can be abolished by several compounds that potentiate the activity of echinocandins, such as drugs targeting the heat shock protein 90 (Hsp90)-calcineurin axis, opening perspectives for adjuvant therapies. Finally, the present and future places of echinocandins as prophylaxis, monotherapy, or combination therapy of IA are discussed in view of the emergence of pan-azole resistance among Aspergillus fumigatus isolates, the occurrence of breakthrough IA, and the advent of new long-lasting echinocandins (rezafungin) or other β-1,3-glucan synthase inhibitors (ibrexafungerp).
Collapse
|
12
|
Prasetyoputri A, Jarrad AM, Cooper MA, Blaskovich MA. The Eagle Effect and Antibiotic-Induced Persistence: Two Sides of the Same Coin? Trends Microbiol 2019; 27:339-354. [DOI: 10.1016/j.tim.2018.10.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 09/21/2018] [Accepted: 10/18/2018] [Indexed: 12/21/2022]
|
13
|
Mercier T, Guldentops E, Lagrou K, Maertens J. Galactomannan, a Surrogate Marker for Outcome in Invasive Aspergillosis: Finally Coming of Age. Front Microbiol 2018; 9:661. [PMID: 29670608 PMCID: PMC5893815 DOI: 10.3389/fmicb.2018.00661] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 03/21/2018] [Indexed: 01/13/2023] Open
Abstract
Detection of galactomannan has become widely available for diagnosing invasive aspergillosis. The test characteristics, using the Platelia™ enzyme-immunoassay, have been well described. This assay could potentially also be useful for the early evaluation of the efficacy of antifungal therapy and for predicting the outcome in terms of response and survival. In this systematic review, we assessed the available evidence for the use of serum galactomannan at baseline as a prognostic marker, and the predictive value of serum galactomannan kinetics after initiation of antifungal therapy. Overall, serum galactomannan at baseline and galactomannan kinetics appear to be good predictors of therapy response and survival. However, breakpoints for predicting therapy failure and validation in different patient populations are still lacking.
Collapse
Affiliation(s)
- Toine Mercier
- Laboratory of Clinical Bacteriology and Mycology, Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium.,Department of Hematology, University Hospitals Leuven, Leuven, Belgium
| | - Ellen Guldentops
- Department of Hematology, University Hospitals Leuven, Leuven, Belgium
| | - Katrien Lagrou
- Laboratory of Clinical Bacteriology and Mycology, Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium.,Department of Laboratory Medicine and National Reference Center for Mycosis, University Hospitals Leuven, Leuven, Belgium
| | - Johan Maertens
- Laboratory of Clinical Bacteriology and Mycology, Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium.,Department of Hematology, University Hospitals Leuven, Leuven, Belgium
| |
Collapse
|
14
|
Stolz DJ, Sands EM, Amarsaikhan N, Tsoggerel A, Templeton SP. Histological Quantification to Determine Lung Fungal Burden in Experimental Aspergillosis. J Vis Exp 2018:57155. [PMID: 29578522 PMCID: PMC5931676 DOI: 10.3791/57155] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The quantification of lung fungal burden is critical for the determination of the relative levels of immune protection and fungal virulence in mouse models of pulmonary fungal infection. Although multiple methods are used to assess fungal burden, quantitative polymerase chain reaction (qPCR) of fungal DNA has emerged as a technique with several advantages over previous culture-based methods. Currently, a comprehensive assessment of lung pathology, leukocyte recruitment, fungal burden, and gene expression in mice with invasive aspergillosis (IA) necessitates the use of a significant number of experimental and control animals. Here the quantification of lung histological staining to determine fungal burden using a reduced number of animals was examined in detail. Lung sections were stained to identify fungal structures with Gomori's modified methanamine silver (GMS) staining. Images were taken from the GMS-stained sections from 4 discrete fields of each formalin-fixed paraffin-embedded lung. The GMS stained areas within each image were quantified using an image analysis program, and from this quantification, the mean percentage of stained area was determined for each sample. Using this strategy, eosinophil-deficient mice exhibited decreased fungal burden and disease with caspofungin therapy, while wild-type mice with IA did not improve with caspofungin. Similarly, fungal burden in mice lacking γδ T cells were also improved by caspofungin, as measured by qPCR and GMS quantification. GMS quantification is therefore introduced as a method for the determination of relative lung fungal burden that may ultimately reduce the quantity of experimental animals required for comprehensive studies of invasive aspergillosis.
Collapse
Affiliation(s)
- Dylan J Stolz
- Department of Microbiology and Immunology, Indiana University School of Medicine - Terre Haute
| | - Ethan M Sands
- Department of Microbiology and Immunology, Indiana University School of Medicine - Terre Haute
| | - Nansalmaa Amarsaikhan
- Department of Microbiology and Immunology, Indiana University School of Medicine - Terre Haute
| | - Angar Tsoggerel
- Department of Microbiology and Immunology, Indiana University School of Medicine - Terre Haute
| | - Steven P Templeton
- Department of Microbiology and Immunology, Indiana University School of Medicine - Terre Haute;
| |
Collapse
|
15
|
Zhao Y, Nagasaki Y, Paderu P, Sugrue MW, Leather HL, Wingard JR, Perlin DS. Applying host disease status biomarkers to therapeutic response monitoring in invasive aspergillosis patients. Med Mycol 2018; 57:38-44. [DOI: 10.1093/mmy/myx164] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 12/19/2017] [Indexed: 02/03/2023] Open
Affiliation(s)
- Yanan Zhao
- Public Health Research Institute, New Jersey Medical School-Rutgers Biomedical and Health Sciences, Newark, New Jersey
| | - Yoji Nagasaki
- Public Health Research Institute, New Jersey Medical School-Rutgers Biomedical and Health Sciences, Newark, New Jersey
| | - Padmaja Paderu
- Public Health Research Institute, New Jersey Medical School-Rutgers Biomedical and Health Sciences, Newark, New Jersey
| | - Michele W Sugrue
- Division of Hematology/Oncology, University of Florida College of Medicine, Gainesville, Florida
| | - Helen L Leather
- Division of Hematology/Oncology, University of Florida College of Medicine, Gainesville, Florida
| | - John R Wingard
- Division of Hematology/Oncology, University of Florida College of Medicine, Gainesville, Florida
| | - David S Perlin
- Public Health Research Institute, New Jersey Medical School-Rutgers Biomedical and Health Sciences, Newark, New Jersey
| |
Collapse
|
16
|
Wagener J, Loiko V. Recent Insights into the Paradoxical Effect of Echinocandins. J Fungi (Basel) 2017; 4:jof4010005. [PMID: 29371498 PMCID: PMC5872308 DOI: 10.3390/jof4010005] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 12/21/2017] [Accepted: 12/22/2017] [Indexed: 12/20/2022] Open
Abstract
Echinocandin antifungals represent one of the most important drug classes for the treatment of invasive fungal infections. The mode of action of the echinocandins relies on inhibition of the β-1,3-glucan synthase, an enzyme essentially required for the synthesis of the major fungal cell wall carbohydrate β-1,3-glucan. Depending on the species, echinocandins may exert fungicidal or fungistatic activity. Apparently independent of this differential activity, a surprising in vitro phenomenon called the “paradoxical effect” can be observed. The paradoxical effect is characterized by the ability of certain fungal isolates to reconstitute growth in the presence of higher echinocandin concentrations, while being fully susceptible at lower concentrations. The nature of the paradoxical effect is not fully understood and has been the focus of multiple studies in the last two decades. Here we concisely review the current literature and propose an updated model for the paradoxical effect, taking into account recent advances in the field.
Collapse
Affiliation(s)
- Johannes Wagener
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Medizinische Fakultät, LMU München, 80336 Munich, Germany.
- Institut für Hygiene und Mikrobiologie, Julius-Maximilians-Universität Würzburg, 97080 Würzburg, Germany.
| | - Veronika Loiko
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Medizinische Fakultät, LMU München, 80336 Munich, Germany.
| |
Collapse
|
17
|
Caspofungin-Mediated Growth Inhibition and Paradoxical Growth in Aspergillus fumigatus Involve Fungicidal Hyphal Tip Lysis Coupled with Regenerative Intrahyphal Growth and Dynamic Changes in β-1,3-Glucan Synthase Localization. Antimicrob Agents Chemother 2017; 61:AAC.00710-17. [PMID: 28760907 DOI: 10.1128/aac.00710-17] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 07/13/2017] [Indexed: 12/26/2022] Open
Abstract
Caspofungin targets cell wall β-1,3-glucan synthesis and is the international consensus guideline-recommended salvage therapy for invasive aspergillosis. Although caspofungin is inhibitory at low concentrations, it exhibits a paradoxical effect (reversal of growth inhibition) at high concentrations by an undetermined mechanism. Treatment with caspofungin at either the growth-inhibitory concentration (0.5 μg/ml) or paradoxical growth-inducing concentration (4 μg/ml) for 24 h caused similar abnormalities, including wider, hyperbranched hyphae, increased septation, and repeated hyphal tip lysis, followed by regenerative intrahyphal growth. By 48 h, only hyphae at the colony periphery treated with the high caspofungin concentration displayed paradoxical growth. A similar high concentration of caspofungin also induced the paradoxical growth of Aspergillus fumigatus during human A549 alveolar cell invasion. Localization of the β-1,3-glucan synthase complex (Fks1 and Rho1) revealed significant differences between cells exposed to the growth-inhibitory and paradoxical growth-inducing concentrations of caspofungin. At both concentrations, Fks1 initially mislocalized from the hyphal tips to vacuoles. However, only continuous exposure to 4 μg/ml of caspofungin for 48 h led to recovery of the normal hyphal morphology with renewed localization of Fks1 to hyphal tips. Rho1 remained at the hyphal tip after treatment with both caspofungin concentrations but was required for paradoxical growth. Farnesol blocked paradoxical growth and relocalized Fks1 and Rho1 to vacuoles. Our results highlight the importance of regenerative intrahyphal growth as a rapid adaptation to the fungicidal lytic effects of caspofungin on hyphal tips and the dynamic localization of Fks1 as part of the mechanism for the caspofungin-mediated paradoxical response in A. fumigatus.
Collapse
|
18
|
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.
Collapse
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
| |
Collapse
|
19
|
Leshinsky J, McLachlan A, Foster DJR, Norris R, Barrs VR. Pharmacokinetics of caspofungin acetate to guide optimal dosing in cats. PLoS One 2017; 12:e0178783. [PMID: 28575121 PMCID: PMC5456383 DOI: 10.1371/journal.pone.0178783] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 05/18/2017] [Indexed: 11/30/2022] Open
Abstract
Cats are the most common mammal to develop invasive fungal rhinosinusitis caused by cryptic species in Aspergillus section Fumigati that are resistant to azoles but susceptible to caspofungin. In this study nonlinear mixed-effects pharmacokinetic modeling and simulation was used to investigate caspofungin pharmacokinetics and explore dosing regimens in cats using caspofungin minimum effective concentrations (MECs). Plasma concentrations in healthy cats were determined using HPLC-MS/MS after administration of a single and seven consecutive daily intravenous doses of 1 mg/kg caspofungin. In the final pharmacokinetic model an optimum maximum concentration (Cmax): MEC ratio of 10–20 was used to guide caspofungin efficacy. Simulations were performed for dosing regimens (doses 0.25–2 mg/kg and 6–72 h dosing intervals) with and without inclusion of a loading dose. Using a 1 mg/kg dose Cmax first dose was 14.8 μg/mL, Cmax at steady state was 19.8 μg/mL, Cmin was 5 μg/mL and Cmax: MEC was >20 in 42.6% of cats after multiple doses. An optimal Cmax: MEC ratio was achieved in caspofungin simulations using 0.75 mg/kg q 24 h or 1 mg/kg q 72h. However, at 1 mg/kg q 72h, Cmin was < MEC (<1 μg/mL) in over 95% of the population. Using a loading dose of 1 mg/kg and a daily dose of 0.75 mg/kg thereafter, the Cmax: MEC was optimal and Cmin was > 2.5 μg/mL for 98% of the population. Based on the modeling data this dosing regimen is likely to achieve target therapeutic concentrations, meet the proposed Cmax: MEC window and provide consistent exposure between doses.
Collapse
Affiliation(s)
- Jana Leshinsky
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camperdown, New South Wales, Australia
| | - Andrew McLachlan
- Faculty of Pharmacy and Education and Research on Ageing, The University of Sydney, Camperdown, New South Wales, Australia
- Concord Hospital, Concord, New South Wales, Australia
| | - David J. R. Foster
- School of Pharmacy and Medical Sciences, Australian Centre for Pharmacometrics, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia, Australia
| | - Ross Norris
- Clinical Pharmacology Division, SydPath, St Vincent’s Hospital, Darlinghurst, New South Wales, Australia
- Clinical School, University of New South Wales, Darlinghurst, New South Wales, Australia
- School of Pharmacy, Griffith University, Gold Coast, Queensland, Australia
| | - Vanessa R. Barrs
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camperdown, New South Wales, Australia
- * E-mail:
| |
Collapse
|
20
|
Borman AM, Fraser M, Palmer MD, Szekely A, Houldsworth M, Patterson Z, Johnson EM. MIC Distributions and Evaluation of Fungicidal Activity for Amphotericin B, Itraconazole, Voriconazole, Posaconazole and Caspofungin and 20 Species of Pathogenic Filamentous Fungi Determined Using the CLSI Broth Microdilution Method. J Fungi (Basel) 2017; 3:E27. [PMID: 29371545 PMCID: PMC5715917 DOI: 10.3390/jof3020027] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 05/23/2017] [Accepted: 05/24/2017] [Indexed: 01/21/2023] Open
Abstract
For filamentous fungi (moulds), species-specific interpretive breakpoints and epidemiological cut-off values (ECVs) have only been proposed for a limited number of fungal species-antifungal agent combinations, with the result that clinical breakpoints are lacking for most emerging mould pathogens. In the current study, we have compiled minimum inhibitory concentration (MIC) data for 4869 clinical mould isolates and present full MIC distributions for amphotericin B, itraconazole, voriconazole, posaconazole, and caspofungin with these isolates which comprise 20 species/genera. In addition, we present the results of an assessment of the fungicidal activity of these same five antifungal agents against a panel of 123 mould isolates comprising 16 of the same species.
Collapse
Affiliation(s)
- Andrew M Borman
- Public Health England United Kingdom, Mycology Reference Laboratory, Myrtle Road, Bristol BS2 8EL, UK.
| | - Mark Fraser
- Public Health England United Kingdom, Mycology Reference Laboratory, Myrtle Road, Bristol BS2 8EL, UK.
| | - Michael D Palmer
- Public Health England United Kingdom, Mycology Reference Laboratory, Myrtle Road, Bristol BS2 8EL, UK.
| | - Adrien Szekely
- Public Health England United Kingdom, Mycology Reference Laboratory, Myrtle Road, Bristol BS2 8EL, UK.
| | - Marian Houldsworth
- Public Health England United Kingdom, Mycology Reference Laboratory, Myrtle Road, Bristol BS2 8EL, UK.
| | - Zoe Patterson
- Public Health England United Kingdom, Mycology Reference Laboratory, Myrtle Road, Bristol BS2 8EL, UK.
| | - Elizabeth M Johnson
- Public Health England United Kingdom, Mycology Reference Laboratory, Myrtle Road, Bristol BS2 8EL, UK.
| |
Collapse
|
21
|
Desoubeaux G, Cray C. Rodent Models of Invasive Aspergillosis due to Aspergillus fumigatus: Still a Long Path toward Standardization. Front Microbiol 2017; 8:841. [PMID: 28559881 PMCID: PMC5432554 DOI: 10.3389/fmicb.2017.00841] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 04/24/2017] [Indexed: 01/09/2023] Open
Abstract
Invasive aspergillosis has been studied in laboratory by the means of plethora of distinct animal models. They were developed to address pathophysiology, therapy, diagnosis, or miscellaneous other concerns associated. However, there are great discrepancies regarding all the experimental variables of animal models, and a thorough focus on them is needed. This systematic review completed a comprehensive bibliographic analysis specifically-based on the technical features of rodent models infected with Aspergillus fumigatus. Out the 800 articles reviewed, it was shown that mice remained the preferred model (85.8% of the referenced reports), above rats (10.8%), and guinea pigs (3.8%). Three quarters of the models involved immunocompromised status, mainly by steroids (44.4%) and/or alkylating drugs (42.9%), but only 27.7% were reported to receive antibiotic prophylaxis to prevent from bacterial infection. Injection of spores (30.0%) and inhalation/deposition into respiratory airways (66.9%) were the most used routes for experimental inoculation. Overall, more than 230 distinct A. fumigatus strains were used in models. Of all the published studies, 18.4% did not mention usage of any diagnostic tool, like histopathology or mycological culture, to control correct implementation of the disease and to measure outcome. In light of these findings, a consensus discussion should be engaged to establish a minimum standardization, although this may not be consistently suitable for addressing all the specific aspects of invasive aspergillosis.
Collapse
Affiliation(s)
- Guillaume Desoubeaux
- Division of Comparative Pathology, Department of Pathology and Laboratory Medicine, Miller School of Medicine, University of MiamiMiami, FL, USA.,Service de Parasitologie-Mycologie-Médecine tropicale, Centre Hospitalier Universitaire de ToursTours, France.,Centre d'Etude des Pathologies Respiratoires (CEPR) Institut National de la Santé et de la Recherche Médicale U1100/Équipe 3, Université François-RabelaisTours, France
| | - Carolyn Cray
- Division of Comparative Pathology, Department of Pathology and Laboratory Medicine, Miller School of Medicine, University of MiamiMiami, FL, USA
| |
Collapse
|
22
|
Kovanda LL, Desai AV, Hope WW. Prognostic value of galactomannan: current evidence for monitoring response to antifungal therapy in patients with invasive aspergillosis. J Pharmacokinet Pharmacodyn 2017; 44:143-151. [PMID: 28181136 DOI: 10.1007/s10928-017-9509-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 02/03/2017] [Indexed: 12/28/2022]
Abstract
Galactomannan (GM) is a polysaccharide present in the cell wall of Aspergillus spp. that is released during growth of the organism. It has been successfully used to aide in the diagnosis of invasive aspergillosis allowing for earlier recognition of disease compared to conventional methods. Since its implementation in the clinic as a diagnostic tool, GM has been used in experimental models to measure therapeutic response. Several clinical studies describe the prognostic value of GM. Herein, we review the evidence supporting the utilization of GM antigen as a biomarker to measure response to systemic antifungal therapy.
Collapse
Affiliation(s)
- Laura L Kovanda
- Astellas Pharma Global Development, Inc., Northbrook, IL, USA. .,Antimicrobial Pharmacodynamics and Therapeutics, Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK.
| | - Amit V Desai
- Astellas Pharma Global Development, Inc., Northbrook, IL, USA
| | - William W Hope
- Antimicrobial Pharmacodynamics and Therapeutics, Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| |
Collapse
|
23
|
Steinbach WJ, Lamoth F, Juvvadi PR. Potential Microbiological Effects of Higher Dosing of Echinocandins. Clin Infect Dis 2016; 61 Suppl 6:S669-77. [PMID: 26567286 DOI: 10.1093/cid/civ725] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The antifungal "paradoxical effect" has been described as the reversal of growth inhibition at high doses of echinocandins, most usually caspofungin. This microbiological effect appears to be a cellular compensatory response to cell wall damage, resulting in alteration of cell wall content and structure as well as fungal morphology and growth. In vitro studies demonstrate this reproducible effect in a certain percentage of fungal isolates, but animal model and clinical studies are less consistent. The calcineurin and Hsp90 cell signaling pathways appear to play a major role in regulating these cellular and structural changes. Regardless of the clinical relevance of this paradoxical growth effect, understanding the specific actions of echinocandins is paramount to optimizing their use at either standard or higher dosing schemes, as well as developing future improvements in our antifungal arsenal.
Collapse
Affiliation(s)
- William J Steinbach
- Division of Pediatric Infectious Diseases, Department of Pediatrics Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina
| | - Frédéric Lamoth
- Division of Pediatric Infectious Diseases, Department of Pediatrics Infectious Diseases Service, Department of Medicine Institute of Microbiology, Lausanne University Hospital, Switzerland
| | | |
Collapse
|
24
|
Longitudinal, in vivo assessment of invasive pulmonary aspergillosis in mice by computed tomography and magnetic resonance imaging. J Transl Med 2016; 96:692-704. [PMID: 27019389 DOI: 10.1038/labinvest.2016.45] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 02/09/2016] [Accepted: 02/23/2016] [Indexed: 11/09/2022] Open
Abstract
Invasive aspergillosis is an emerging threat to public health due to the increasing use of immune suppressive drugs and the emergence of resistance against antifungal drugs. To deal with this threat, research on experimental disease models provides insight into the pathogenesis of infections caused by susceptible and resistant Aspergillus strains and by assessing their response to antifungal drugs. However, standard techniques used to evaluate infection in a preclinical setting are severely limited by their invasive character, thereby precluding evaluation of disease extent and therapy effects in the same animal. To enable non-invasive, longitudinal monitoring of invasive pulmonary aspergillosis in mice, we optimized computed tomography (CT) and magnetic resonance imaging (MRI) techniques for daily follow-up of neutropenic BALB/c mice intranasally infected with A. fumigatus spores. Based on the images, lung parameters (signal intensity, lung tissue volume and total lung volume) were quantified to obtain objective information on disease onset, progression and extent for each animal individually. Fungal lung lesions present in infected animals were successfully visualized and quantified by both CT and MRI. By using an advanced MR pulse sequence with ultrashort echo times, pathological changes within the infected lung became visually and quantitatively detectable at earlier disease stages, thereby providing valuable information on disease onset and progression with high sensitivity. In conclusion, these non-invasive imaging techniques prove to be valuable tools for the longitudinal evaluation of dynamic disease-related changes and differences in disease severity in individual animals that might be readily applied for rapid and cost-efficient drug screening in preclinical models in vivo.
Collapse
|
25
|
Efficacy of the investigational echinocandin ASP9726 in a guinea pig model of invasive pulmonary aspergillosis. Antimicrob Agents Chemother 2015; 59:2875-81. [PMID: 25753643 DOI: 10.1128/aac.04857-14] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 03/02/2015] [Indexed: 11/20/2022] Open
Abstract
ASP9726 is an investigational echinocandin with in vitro activity against Aspergillus species. We evaluated the pharmacokinetics and efficacy of this agent in an established guinea pig model of invasive pulmonary aspergillosis. ASP9726 plasma concentrations were measured in guinea pigs administered either a single dose or multiple doses of this agent at 2.5, 5, and 10 mg/kg of body weight/day by subcutaneous injection. Immunosuppressed guinea pigs were inoculated with A. fumigatus AF293, and ASP9726 (2.5, 5, and 10 mg/kg/day), voriconazole (10 mg/kg by oral gavage twice daily), or caspofungin (3 mg/kg/day by intraperitoneal injection) was administered for 8 days. Changes in fungal burden were measured by enumerating CFU and by quantitative PCR of specimens from within the lungs, as well as by analysis of serum (1 → 3)-β-D-glucan and galactomannan. Lung histopathology was also evaluated. ASP9726 plasma concentrations increased in a dose-proportional manner, and the drug was well tolerated at each dose. Each dose of ASP9726, voriconazole, and caspofungin significantly reduced pulmonary fungal burden as measured by quantitative PCR and by determining (1 → 3)-β-D-glucan and galactomannan levels, but only voriconazole significantly reduced numbers of CFU. ASP9726 at 5 mg/kg also significantly improved survival. Histopathology demonstrated morphological changes in hyphae in animals exposed to ASP9726 and caspofungin, consistent with the activities of the echinocandins. These results suggest that ASP9726 may be efficacious for the treatment of invasive pulmonary aspergillosis.
Collapse
|
26
|
Dichtl K, Samantaray S, Aimanianda V, Zhu Z, Prévost MC, Latgé JP, Ebel F, Wagener J. Aspergillus fumigatus devoid of cell wall β-1,3-glucan is viable, massively sheds galactomannan and is killed by septum formation inhibitors. Mol Microbiol 2014; 95:458-71. [PMID: 25425041 DOI: 10.1111/mmi.12877] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/18/2014] [Indexed: 12/01/2022]
Abstract
Echinocandins inhibit β-1,3-glucan synthesis and are one of the few antimycotic drug classes effective against Aspergillus spp. In this study, we characterized the β-1,3-glucan synthase Fks1 of Aspergillus fumigatus, the putative target of echinocandins. Data obtained with a conditional mutant suggest that fks1 is not essential. In agreement, we successfully constructed a viable Δfks1 deletion mutant. Lack of Fks1 results in characteristic growth phenotypes similar to wild type treated with echinocandins and an increased susceptibility to calcofluor white and sodium dodecyl sulfate. In agreement with Fks1 being the only β-1,3-glucan synthase in A. fumigatus, the cell wall is devoid of β-1,3-glucan. This is accompanied by a compensatory increase of chitin and galactosaminogalactan and a significant decrease in cell wall galactomannan due to a massively enhanced galactomannan shedding. Our data furthermore suggest that inhibition of hyphal septation can overcome the limitations of echinocandin therapy. Compounds inhibiting septum formation boosted the antifungal activity of caspofungin. Thus, development of clinically applicable inhibitors of septum formation is a promising strategy to improve existing antifungal therapy.
Collapse
Affiliation(s)
- Karl Dichtl
- Max von Pettenkofer-Institut für Hygiene und Medizinische Mikrobiologie, Ludwig-Maximilians-Universität München, 80336, Munich, Germany
| | | | | | | | | | | | | | | |
Collapse
|
27
|
Abstract
Successful treatment of infectious diseases requires choice of the most suitable antimicrobial agent, comprising consideration of drug pharmacokinetics (PK), including penetration into infection site, pathogen susceptibility, optimal route of drug administration, drug dose, frequency of administration, duration of therapy, and drug toxicity. Antimicrobial pharmacokinetic/pharmacodynamic (PK/PD) studies consider these variables and have been useful in drug development, optimizing dosing regimens, determining susceptibility breakpoints, and limiting toxicity of antifungal therapy. Here the concepts of antifungal PK/PD studies are reviewed, with emphasis on methodology and application. The initial sections of this review focus on principles and methodology. Then the pharmacodynamics of each major antifungal drug class (polyenes, flucytosine, azoles, and echinocandins) is discussed. Finally, the review discusses novel areas of pharmacodynamic investigation in the study and application of combination therapy.
Collapse
|
28
|
Hadrich I, Neji S, Makni F, Ayadi A, Elloumi M, Ranque S. Trailing or paradoxical growth of Aspergillus flavus exposed to caspofungin is independent of genotype. J Med Microbiol 2014; 63:1584-1589. [PMID: 25210202 DOI: 10.1099/jmm.0.076000-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
There are limited data on in vitro susceptibility testing of echinocandins against Aspergillus species. The objective of this study was to describe the phenotypes of Aspergillus flavus observed on exposure to caspofungin in vitro and to test whether these phenotypes were associated with A. flavus genotypes. The caspofungin MICs of 37 A. flavus clinical isolates collected from 14 patients with invasive aspergillosis were determined using Etest assays. Caspofungin MICs ranged from 0.012 to 0.064 mg l(-1); the modal MIC was 0.023 mg l(-1) and the MIC₅₀ and MIC₉₀ were 0.032 and 0.064 mg l(-1), respectively. A clear end point was noted in 24 (65 %) isolates, whereas seven (19 %) displayed a trailing effect and six (16 %) showed paradoxical growth when exposed to caspofungin. In these A. flavus isolates, the absence of a significant population structure or genetic differentiation indicated that trailing or paradoxical growth phenotypes were independent of microsatellite genotype.
Collapse
Affiliation(s)
- Inès Hadrich
- Laboratoire de Biologie Moléculaire Parasitaire et Fongique, Faculté de Médecine de Sfax, Rue Magida Boulila, 3029 Sfax, Tunisia
| | - Sourour Neji
- Laboratoire de Biologie Moléculaire Parasitaire et Fongique, Faculté de Médecine de Sfax, Rue Magida Boulila, 3029 Sfax, Tunisia
| | - Fattouma Makni
- Laboratoire de Biologie Moléculaire Parasitaire et Fongique, Faculté de Médecine de Sfax, Rue Magida Boulila, 3029 Sfax, Tunisia
| | - Ali Ayadi
- Laboratoire de Biologie Moléculaire Parasitaire et Fongique, Faculté de Médecine de Sfax, Rue Magida Boulila, 3029 Sfax, Tunisia
| | - Moez Elloumi
- Service d'Onco-hématologie, CHU Hedi-Chaker, 3029 Sfax, Tunisia
| | - Stéphane Ranque
- Aix-Marseille Université, IP-TPT UMR MD3, 13885 Marseille, France.,Parasitology & Mycology, CHU Timone-Adultes, Assistance Publique-Hôpitaux de Marseille, 13005 Marseille, France
| |
Collapse
|
29
|
Hohl TM. Overview of vertebrate animal models of fungal infection. J Immunol Methods 2014; 410:100-12. [PMID: 24709390 DOI: 10.1016/j.jim.2014.03.022] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 03/17/2014] [Accepted: 03/24/2014] [Indexed: 01/27/2023]
Abstract
Fungi represent emerging infectious threats to human populations worldwide. Mice and other laboratory animals have proved invaluable in modeling clinical syndromes associated with superficial and life-threatening invasive mycoses. This review outlines salient features of common vertebrate animal model systems to study fungal pathogenesis, host antifungal immune responses, and antifungal compounds.
Collapse
Affiliation(s)
- Tobias M Hohl
- Department of Medicine, Infectious Diseases Service, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, Box 9, New York, NY 10075, United States.
| |
Collapse
|
30
|
Lestner JM, Smith PB, Cohen-Wolkowiez M, Benjamin DK, Hope WW. Antifungal agents and therapy for infants and children with invasive fungal infections: a pharmacological perspective. Br J Clin Pharmacol 2014; 75:1381-95. [PMID: 23126319 DOI: 10.1111/bcp.12025] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Accepted: 10/31/2012] [Indexed: 12/30/2022] Open
Abstract
Invasive fungal infections, although relatively rare, are life-threatening diseases in premature infants and immunocompromised children. While many advances have been made in antifungal therapeutics in the last two decades, knowledge of the pharmacokinetics and pharmacodynamics of antifungal agents for infants and children remains incomplete. This review summarizes the pharmacology and clinical utility of currently available antifungal agents and discusses the opportunities and challenges for future research.
Collapse
Affiliation(s)
- Jodi M Lestner
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK
| | | | | | | | | |
Collapse
|
31
|
Vanstraelen K, Lagrou K, Maertens J, Wauters J, Willems L, Spriet I. The Eagle-like effect of echinocandins: what’s in a name? Expert Rev Anti Infect Ther 2014; 11:1179-91. [DOI: 10.1586/14787210.2013.841543] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
32
|
Abstract
The echinocandins are a novel class of antifungal agents that have come into use over the past 10 years. The mechanism of action of these lipopeptide agents is via noncompetitive inhibition of the synthesis of 1,3-beta-glucans, which are fungal cell wall constituents. All agents of this class are only available in an intravenous formulation. The first approved agent of this class was caspofungin (Cancidas). Caspofungin is a therapeutic option for patients with candidal esophagitis and deep-seated candidal infections, and is an alternative therapy for Aspergillus infections, especially in the salvage setting. In addition, it is a therapeutic option for the empiric therapy of febrile neutropenia. The usefulness of this agent in treating less common fungal infections has been cited in anecdotal reports. One major limitation of this drug is the lack of an oral formulation. Caspofungin may be considered as a component of combination antifungal regimens. Caspofungin represents a significant advance in the care of patients with serious fungal infections.
Collapse
Affiliation(s)
- Vicki A Morrison
- University of Minnesota, Veterans Affairs Medical Center, Minneapolis, MN 55417, USA.
| |
Collapse
|
33
|
Abstract
The echinocandins are a new and unique class of antifungal agents that act on the fungal cell wall by way of noncompetitive inhibition of the synthesis of 1,3-beta-glucans. All agents of this class are of parenteral formulation, with no oral preparations available. Caspofungin (Cancidas) was the first approved echinocandin, followed recently by micafungin (Mycamine) and anidulafungin (Eraxis). The precise role of the echinocandins in the antifungal armamentarium is still unfolding. Caspofungin is approved for the treatment of candidal esophagitis and candidemia, salvage therapy of Aspergillus infections and for empirical therapy of febrile neutropenia. Micafungin is likewise approved for candidal esophagitis, in addition to antifungal prophylaxis for hematopoietic stem cell transplant recipients. Anidulafungin is also approved for treatment of candidal esophagitis, as well as therapy of candidemia. There has been anecdotal use of these agents to treat less common fungal pathogens, as well as limited use as a component of combination antifungal therapy. The echinocandins are an important addition to the antifungal armamentarium in the treatment of fungal infections in both immunocompromised patients and those with normal immunity.
Collapse
Affiliation(s)
- Vicki A Morrison
- Hematology/Oncology and Infectious Disease, Veterans Affairs Medical Center, University of Minnesota, Minneapolis, MN 55417, USA.
| |
Collapse
|
34
|
Lepak AJ, Marchillo K, VanHecker J, Andes DR. Impact of in vivo triazole and echinocandin combination therapy for invasive pulmonary aspergillosis: enhanced efficacy against Cyp51 mutant isolates. Antimicrob Agents Chemother 2013; 57:5438-47. [PMID: 23959322 PMCID: PMC3811282 DOI: 10.1128/aac.00833-13] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 08/13/2013] [Indexed: 11/20/2022] Open
Abstract
Previous studies examining combination therapy for invasive pulmonary aspergillosis (IPA) have revealed conflicting results, including antagonism, indifference, and enhanced effects. The most commonly employed combination for this infection includes a mold-active triazole and echinocandin. Few studies have evaluated combination therapy from a pharmacodynamic (PD) perspective, and even fewer have examined combination therapy against both wild-type and azole-resistant Cyp51 mutant isolates. The current studies aim to fill this gap in knowledge. Four Aspergillus fumigatus isolates were utilized, including a wild-type strain, an Fks1 mutant (posaconazole susceptible and caspofungin resistant), and two Cyp51 mutants (posaconazole resistant). A neutropenic murine model of IPA was used for the treatment studies. The dosing design included monotherapy with posaconazole, monotherapy with caspofungin, and combination therapy with both. Efficacy was determined using quantitative PCR, and results were normalized to known quantities of conidia (conidial equivalents [CE]). The static dose, 1-log kill dose, and associated PD target area under the curve (AUC)/MIC ratio were determined for monotherapy and combination therapy. Monotherapy experiments revealed potent activity for posaconazole, with reductions of 3 to 4 log10 Aspergillus CE/ml with the two "low"-MIC isolates. Posaconazole alone was less effective for the two isolates with higher MICs. Caspofungin monotherapy did not produce a significant decrease in fungal burden for any strain. Combination therapy with the two antifungals did not enhance efficacy for the two posaconazole-susceptible isolates. However, the drug combination produced synergistic activity against both posaconazole-resistant isolates. Specifically, the combination resulted in a 1- to 2-log10 decline in burden that would not have been predicted based on the monotherapy results for each drug. This corresponded to a reduction in the free-drug posaconazole AUC/MIC ratio needed for stasis of up to 17-fold. The data suggest that combination therapy using a triazole and an echinocandin may be a beneficial treatment strategy for triazole-resistant isolates.
Collapse
|
35
|
Such KA, Petraitis V, Petraitiene R, Strauss GE, Moradi PW, Walsh TJ. Environmental monitoring for Aspergillus fumigatus in association with an immunosuppressed rabbit model of pulmonary aspergillosis. JOURNAL OF THE AMERICAN ASSOCIATION FOR LABORATORY ANIMAL SCIENCE : JAALAS 2013; 52:541-544. [PMID: 24041208 PMCID: PMC3784658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 03/12/2013] [Accepted: 04/09/2013] [Indexed: 06/02/2023]
Abstract
Aspergillus fumigatus causes life-threatening pneumonia in immunocompromised patients. Conidia, the infectious form of the organism, are handled in a biologic safety cabinet under BSL2 conditions. However because germinated conidia form noninfectious hyphae in tissue, we hypothesized that rabbits inoculated intratracheally would grow A. fumigatus in their lungs but that the environment would remain free of this fungus, potentially permitting maintenance of infected animals under ABSL1 conditions. We performed a surveillance study for the presence of A. fumigatus in the environment before proceeding with antifungal therapy studies of experimental pulmonary aspergillosis. The expected outcome included absence of A. fumigatus in the environment, stool, and blood and presence in rabbit lungs. Female SPF New Zealand white rabbits were immunosuppressed and inoculated intratracheally (n = 4) or intraesophageally (n = 2) with 1.25 × 10(8) conidia of A. fumigatus. Feces, pan liners, and walls were sampled daily during the 11-d experiment, and blood was sampled on days 2, 6, and 8 after inoculation. Samples were cultured on 5% Sabouraud glucose agar plates. Lungs were weighed and scored for hemorrhagic infarcts and homogenized for culture on 5% Sabouraud glucose agar and trypticase soy agar plates. Blood cultures, rabbit stool, and environmental swabs were all negative for A. fumigatus whereas the lungs inoculated intratracheally demonstrated 4.5 × 10(2) ± 0.8 × 10(2) CFU/g of A. fumigatus. Therefore, neutropenic rabbits with experimental invasive pulmonary aspergillosis do not shed conidia of A. fumigatus and can be safely housed under ABSL1 conditions after inoculation.
Collapse
Affiliation(s)
- Kimberly A Such
- Tri-Institutional Training Program in Laboratory Animal Medicine and Science
- The Rockefeller University, Memorial Sloan-Kettering Cancer Center, and Weill Cornell Medical College, and
| | - Vidmantas Petraitis
- Department of Medicine, Infectious Diseases Division, Weill Cornell Medical College of Cornell University, New York, New York
| | - Ruta Petraitiene
- Department of Medicine, Infectious Diseases Division, Weill Cornell Medical College of Cornell University, New York, New York
| | - Gittel E Strauss
- Department of Medicine, Infectious Diseases Division, Weill Cornell Medical College of Cornell University, New York, New York
| | - Patriss-Wais Moradi
- Department of Medicine, Infectious Diseases Division, Weill Cornell Medical College of Cornell University, New York, New York
| | - Thomas J Walsh
- Department of Medicine, Infectious Diseases Division, Weill Cornell Medical College of Cornell University, New York, New York
| |
Collapse
|
36
|
Population pharmacokinetics of escalating doses of caspofungin in a phase II study of patients with invasive aspergillosis. Antimicrob Agents Chemother 2013; 57:1664-71. [PMID: 23335740 DOI: 10.1128/aac.01912-12] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Caspofungin (CAS) is approved for second-line management of proven or probable invasive aspergillosis at a dose of 50 mg once daily (QD). Preclinical and limited clinical data support the concept of the dose-dependent antifungal efficacy of CAS with preservation of its favorable safety profile. Little is known, however, about the pharmacokinetics (PKs) of higher doses of CAS in patients. In a formal multicenter phase II dose-escalation study, CAS was administered as a 2-h infusion at doses ranging from 70 to 200 mg QD. CAS PK sampling (n = 468 samples) was performed on day 1 and at peak and trough time points on days 4, 7, 14, and 28 (70 mg, n = 9 patients; 100 mg, n = 8 patients; 150 mg, n = 9 patients; 200 mg, n = 20 patients; total, n = 46 patients). Drug concentrations in plasma were measured by liquid chromatography tandem mass spectroscopy. Population pharmacokinetic analysis (PopPK) was performed using NONMEM (version 7) software. Model evaluation was performed using bootstrap analysis, prediction-corrected visual predictive check (pcVPC), as well as standardized visual predictive check (SVPC). The four investigated dose levels showed no difference in log-transformed dose-normalized trough levels of CAS (analysis of variance). CAS concentration data fitted best to a two-compartment model with a proportional-error model, interindividual variability (IIV) fitted best on clearance (CL), central and peripheral volume of distribution (V(1) and V(2), respectively) covariance fitted best on CL and V(1), interoccasion variability (IOV) fitted best on CL, and body weight fitted best as a covariate on CL and V(1) (CL, 0.411 liters/h ± 29% IIV; IOV on CL, 16%; V(1), 5.785 liters ± 29% IIV; intercompartmental clearance, 0.843 liters/h; V2, 6.53 liters ± 67% IIV). None of the other examined covariates (dose level, gender, age, serum bilirubin concentration, creatinine clearance) improved the model further. Bootstrap results showed the robustness of the final PopPK model. pcVPC and SVPC showed the predictability of the model and further confirmed the linear PKs of CAS over the dosage range of 70 to 200 mg QD. On the basis of the final model, geometric mean simulated peak plasma levels at steady state ranged from 13.8 to 39.4 mg/liter (geometric coefficient of variation, 31%), geometric mean trough levels ranged from 4.2 to 12.0 mg/liter (49%), and geometric mean areas under the concentration-time curves ranged from 170 to 487 mg · h/liter (34%) for the dosage range of 70 to 200 mg QD. CAS showed linear PKs across the investigated dosage range of 70 to 200 mg QD. Drug exposure in the present study population was comparable to that in other populations. (This study has been registered with the European Union Drug Regulating Authorities Clinical Trials website under registration no. 2006-001936-30 and at ClinicalTrials.gov under registration no. NCT00404092.).
Collapse
|
37
|
Barton RC. Laboratory diagnosis of invasive aspergillosis: from diagnosis to prediction of outcome. SCIENTIFICA 2013; 2013:459405. [PMID: 24278780 PMCID: PMC3820361 DOI: 10.1155/2013/459405] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 11/14/2012] [Indexed: 06/02/2023]
Abstract
Invasive aspergillosis (IA), an infection caused by fungi in the genus Aspergillus, is seen in patients with immunological deficits, particularly acute leukaemia and stem cell transplantation, and has been associated with high rates of mortality in previous years. Diagnosing IA has long been problematic owing to the inability to culture the main causal agent A. fumigatus from blood. Microscopic examination and culture of respiratory tract specimens have lacked sensitivity, and biopsy tissue for histopathological examination is rarely obtainable. Thus, for many years there has been a great interest in nonculture-based techniques such as the detection of galactomannan, β -D-glucan, and DNA by PCR-based methods. Recent meta-analyses suggest that these approaches have broadly similar performance parameters in terms of sensitivity and specificity to diagnose IA. Improvements have been made in our understanding of the limitations of antigen assays and the standardisation of PCR-based DNA detection. Thus, in more recent years, the debate has focussed on how these assays can be incorporated into diagnostic strategies to maximise improvements in outcome whilst limiting unnecessary use of antifungal therapy. Furthermore, there is a current interest in applying these tests to monitor the effectiveness of therapy after diagnosis and predict clinical outcomes. The search for improved markers for the early and sensitive diagnosis of IA continues to be a challenge.
Collapse
Affiliation(s)
- Richard C. Barton
- Mycology Reference Centre, Department of Microbiology, Leeds Teaching Hospitals Trust, Leeds LS1 3EX, UK
| |
Collapse
|
38
|
Animal Models In Mycology: What Have We Learned Over The Past 30 Years. CURRENT FUNGAL INFECTION REPORTS 2012. [DOI: 10.1007/s12281-012-0126-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
39
|
Combination of voriconazole and anidulafungin for treatment of triazole-resistant aspergillus fumigatus in an in vitro model of invasive pulmonary aspergillosis. Antimicrob Agents Chemother 2012; 56:5180-5. [PMID: 22825124 DOI: 10.1128/aac.01111-12] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Voriconazole is a first-line agent for the treatment of invasive pulmonary aspergillosis. Isolates with elevated voriconazole MICs are increasingly being seen, and the optimal treatment regimen is not defined. We investigated whether the combination of voriconazole with anidulafungin may be beneficial for the treatment of A. fumigatus strains with elevated voriconazole MICs. We used an in vitro model of the human alveolus to define the exposure-response relationships for a wild-type strain (voriconazole MIC, 0.5 mg/liter) and strains with defined molecular mechanisms of triazole resistance (MICs, 4 to 16 mg/liter). All strains had anidulafungin minimum effective concentrations (MECs) of 0.0078 mg/liter. Exposure-response relationships were estimated using galactomannan as a biomarker. Concentrations of voriconazole and anidulafungin were measured using high-performance liquid chromatography (HPLC). The interaction of voriconazole and anidulafungin was described using the Greco model. Fungal growth was progressively inhibited with higher drug exposures of voriconazole. Strains with elevated voriconazole MICs required proportionally greater voriconazole exposures to achieve a comparable antifungal effect. Galactomannan concentrations were only marginally reduced by anidulafungin monotherapy. An additive effect between voriconazole and anidulafungin was apparent. In conclusion, the addition of anidulafungin does not markedly alter the exposure-response relationship of voriconazole. A rise in serum galactomannan during combination therapy with voriconazole and anidulafungin should be interpreted as treatment failure and not attributed to a paradoxical reaction related to echinocandin treatment.
Collapse
|
40
|
Seeber K, Duettmann W, Krause R, Hoenigl M. Usefulness of the Serum Galactomannan Assay for Early Response Assessment and Treatment Stratifications of Invasive Aspergillosis. CURRENT FUNGAL INFECTION REPORTS 2012. [DOI: 10.1007/s12281-012-0099-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
41
|
DIGE enables the detection of a putative serum biomarker of fungal origin in a mouse model of invasive aspergillosis. J Proteomics 2012; 75:2536-49. [DOI: 10.1016/j.jprot.2012.01.040] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 01/27/2012] [Accepted: 01/30/2012] [Indexed: 11/20/2022]
|
42
|
Pharmacodynamic effects of simulated standard doses of antifungal drugs against Aspergillus species in a new in vitro pharmacokinetic/pharmacodynamic model. Antimicrob Agents Chemother 2011; 56:403-10. [PMID: 22064546 DOI: 10.1128/aac.00662-11] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In conventional ΜΙC tests, fungi are exposed to constant drug concentrations, whereas in vivo, fungi are exposed to changing drug concentrations. Therefore, we developed a new in vitro pharmacokinetic/pharmacodynamic model where human plasma pharmacokinetics of standard doses of 1 mg/kg amphotericin B, 4 mg/kg voriconazole, and 1 mg/kg caspofungin were simulated and their pharmacodynamic characteristics were determined against three clinical isolates of Aspergillus fumigatus, Aspergillus flavus, and Aspergillus terreus with identical MICs (1 mg/liter for amphotericin B, 0.5 mg/liter for voriconazole) and minimum effective concentrations (0.5 mg/liter for caspofungin). This new model consists of an internal compartment (a 10-ml dialysis tube made out of a semipermeable cellulose membrane allowing the free diffusion of antifungals but not galactomannan) inoculated with Aspergillus conidia and placed inside an external compartment (a 700-ml glass beaker) whose content is diluted after the addition of antifungal drugs by a peristaltic pump at the same rate as the clearance of the antifungal drugs in human plasma. Fungal growth was assessed by galactomannan production. Despite demonstrating the same MICs, amphotericin B completely inhibited (100%) A. fumigatus but not A. flavus and A. terreus, whose growth was delayed for 7.53 and 22.8 h, respectively. Voriconazole partially inhibited A. fumigatus (49.5%) and Α. flavus (27.9%) but not Α. terreus; it delayed their growth by 3.99 h (A. fumigatus) and 5.37 h (Α. terreus). Caspofungin did not alter galactomannan production in all of the species but A. terreus. The new model simulated human pharmacokinetics of antifungal drugs and revealed important pharmacodynamic differences in their activity.
Collapse
|
43
|
Elevated cell wall chitin in Candida albicans confers echinocandin resistance in vivo. Antimicrob Agents Chemother 2011; 56:208-17. [PMID: 21986821 DOI: 10.1128/aac.00683-11] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Candida albicans cells with increased cell wall chitin have reduced echinocandin susceptibility in vitro. The aim of this study was to investigate whether C. albicans cells with elevated chitin levels have reduced echinocandin susceptibility in vivo. BALB/c mice were infected with C. albicans cells with normal chitin levels and compared to mice infected with high-chitin cells. Caspofungin therapy was initiated at 24 h postinfection. Mice infected with chitin-normal cells were successfully treated with caspofungin, as indicated by reduced kidney fungal burdens, reduced weight loss, and decreased C. albicans density in kidney lesions. In contrast, mice infected with high-chitin C. albicans cells were less susceptible to caspofungin, as they had higher kidney fungal burdens and greater weight loss during early infection. Cells recovered from mouse kidneys at 24 h postinfection with high-chitin cells had 1.6-fold higher chitin levels than cells from mice infected with chitin-normal cells and maintained a significantly reduced susceptibility to caspofungin when tested in vitro. At 48 h postinfection, caspofungin treatment induced a further increase in chitin content of C. albicans cells harvested from kidneys compared to saline treatment. Some of the recovered clones had acquired, at a low frequency, a point mutation in FKS1 resulting in a S645Y amino acid substitution, a mutation known to confer echinocandin resistance. This occurred even in cells that had not been exposed to caspofungin. Our results suggest that the efficacy of caspofungin against C. albicans was reduced in vivo due to either elevation of chitin levels in the cell wall or acquisition of FKS1 point mutations.
Collapse
|
44
|
Phase II dose escalation study of caspofungin for invasive Aspergillosis. Antimicrob Agents Chemother 2011; 55:5798-803. [PMID: 21911573 DOI: 10.1128/aac.05134-11] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Our objective was to evaluate the maximum tolerated dose of caspofungin for invasive aspergillosis (IA). The safety and pharmacokinetics of escalating dosages of caspofungin were investigated in IA. Eight patients each received caspofungin 70, 100, 150, or 200 mg once a day (QD). Dose-limiting toxicity (DLT) was defined as the same non-hematological treatment-related adverse event of grade ≥ 4 in 2 of 8 patients or ≥ 3 in 4 of 8 patients in a cohort. A total of 46 patients (median age, 61 years; 21 female; 89% with hematological malignancies) received caspofungin (9, 8, 9, and 20 patients in the 70-, 100-, 150-, and 200-mg cohorts) for a median of 24.5 days. Plasma pharmacokinetics were linear across the investigated dosages and followed a two-compartment model, with weight as the covariate on clearance and sex as the covariate on central volume of distribution. Simulated peak plasma concentrations at steady state ranged from 14.2 to 40.6 mg/liter (28%), trough concentrations from 4.1 to 11.8 mg/liter (58%), and area under the concentration-time curve from 175 to 500 mg/liter/h (32%) (geometric mean, geometric coefficient of variation). Treatment was well tolerated without dose-limiting toxicity. The rate of complete or partial responses was 54.3%, and the overall mortality at 12-week follow-up was 28.3%. In first-line treatment of invasive aspergillosis, daily doses of up to 200 mg caspofungin were well tolerated and the maximum tolerated dose was not reached. Pharmacokinetics was linear. Response rates were similar to those previously reported for voriconazole and liposomal amphotericin.
Collapse
|
45
|
Nouér SA, Nucci M, Kumar NS, Grazziutti M, Barlogie B, Anaissie E. Earlier response assessment in invasive aspergillosis based on the kinetics of serum Aspergillus galactomannan: proposal for a new definition. Clin Infect Dis 2011; 53:671-6. [PMID: 21846834 DOI: 10.1093/cid/cir441] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Current criteria for assessing treatment response of invasive aspergillosis (IA) rely on nonspecific subjective parameters. We hypothesized that an Aspergillus-specific response definition based on the kinetics of serum Aspergillus galactomannan index (GMI) would provide earlier and more objective response assessment. METHODS We compared the 6-week European Organization for Research and Treatment of Cancer/Mycoses Study Group (EORTC/MSG) response criteria with GMI-based response among 115 cancer patients with IA. Success according to GMI required survival with repeatedly negative GMI for ≥2 weeks. Time to response and agreement between the 2 definitions were the study endpoints. RESULTS Success according to EORTC/MSG and GMI criteria was observed in 73 patients (63%) and 83 patients (72%), respectively. The GMI-based response was determined at a median of 21 days after treatment initiation (range, 15-41 days), 3 weeks before the EORTC/MSG time point, in 72 (87%) of 83 responders. Agreement between definitions was shown in all 32 nonresponders and in 73 of the 83 responders (91% overall), with an excellent κ correlation coefficient of 0.819. Among 10 patients with discordant response (EORTC/MSG failure, GMI success), 1 is alive without IA 3 years after diagnosis; for the other, aspergillosis could not be detected at autopsy. The presence of other life-threatening complications in the remaining 8 patients indicates that IA had resolved. CONCLUSIONS The Aspergillus-specific GMI-based criteria compare favorably to current response definitions for IA and significantly shorten time to response assessment. These criteria rely on a simple, reproducible, objective, and Aspergillus-specific test and should serve as the primary endpoint in trials of IA.
Collapse
Affiliation(s)
- Simone A Nouér
- Department of Preventive Medicine and Myeloma Institute forResearch and Therapy, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | | | | | | | | | | |
Collapse
|
46
|
Abstract
The incidence of invasive fungal infections, especially those due to Aspergillus spp. and Candida spp., continues to increase. Despite advances in medical practice, the associated mortality from these infections continues to be substantial. The echinocandin antifungals provide clinicians with another treatment option for serious fungal infections. These agents possess a completely novel mechanism of action, are relatively well-tolerated, and have a low potential for serious drug-drug interactions. At the present time, the echinocandins are an option for the treatment of infections due Candida spp (such as esophageal candidiasis, invasive candidiasis, and candidemia). In addition, caspofungin is a viable option for the treatment of refractory aspergillosis. Although micafungin is not Food and Drug Administration-approved for this indication, recent data suggests that it may also be effective. Finally, caspofungin- or micafungin-containing combination therapy should be a consideration for the treatment of severe infections due to Aspergillus spp. Although the echinocandins share many common properties, data regarding their differences are emerging at a rapid pace. Anidulafungin exhibits a unique pharmacokinetic profile, and limited cases have shown a potential far activity in isolates with increased minimum inhibitory concentrations to caspofungin and micafungin. Caspofungin appears to have a slightly higher incidence of side effects and potential for drug-drug interactions. This, combined with some evidence of decreasing susceptibility among some strains of Candida, may lessen its future utility. However, one must take these findings in the context of substantially more data and use with caspofungin compared with the other agents. Micafungin appears to be very similar to caspofungin, with very few obvious differences between the two agents.
Collapse
Affiliation(s)
- Gregory Eschenauer
- Department of Pharmacy Services, University of Michigan Health System
- Department of Clinical Sciences, College of Pharmacy, University of Michigan
| | - Daryl D DePestel
- Department of Pharmacy Services, University of Michigan Health System
- Department of Clinical Sciences, College of Pharmacy, University of Michigan
| | - Peggy L Carver
- Department of Pharmacy Services, University of Michigan Health System
- Department of Clinical Sciences, College of Pharmacy, University of Michigan
| |
Collapse
|
47
|
Cattaneo C, Monte S, Algarotti A, Audisio E, Borlenghi E, Campiotti L, Cerqui E, Fanizza C, Giuliani R, Mico C, Rocconi R, Salvi A, Salvi F, Verga L, Levis A, Lambertenghi Deliliers G, Pogliani EM, Tognoni G, Rambaldi A, Rossi G. A randomized comparison of caspofungin versus antifungal prophylaxis according to investigator policy in acute leukaemia patients undergoing induction chemotherapy (PROFIL-C study). J Antimicrob Chemother 2011; 66:2140-5. [DOI: 10.1093/jac/dkr271] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
|
48
|
Gonzales DA, De Torre C, Wang H, Devor CB, Munson PJ, Ying SX, Kern SJ, Petraitiene R, Levens DL, Walsh TJ, Suffredini AF. Protein expression profiles distinguish between experimental invasive pulmonary aspergillosis and Pseudomonas pneumonia. Proteomics 2011; 10:4270-80. [PMID: 21089047 DOI: 10.1002/pmic.200900768] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We hypothesized that invasive pulmonary aspergillosis (IPA) may generate a distinctive proteomic signature in plasma and bronchoalveolar lavage (BAL). Proteins in plasma and BAL from two neutropenic rabbit models of IPA and Pseudomonas pneumonia were analyzed by SELDI-TOF MS. Hierarchical clustering analysis of plasma time course spectra demonstrated two clusters of peaks that were differentially regulated between IPA and Pseudomonas pneumonia (57 and 34 peaks, respectively, p<0.001). PCA of plasma proteins demonstrated a time-dependent separation of the two infections. A random forest analysis that ranked the top 30 spectral points distinguished between late Aspergillus and Pseudomonas pneumonias with 100% sensitivity and specificity. Based on spectral data analysis, three proteins were identified using SDS-PAGE and LC/MS and quantified using reverse phase arrays. Differences in the temporal sequence of plasma haptoglobin (p<0.001), apolipoprotein A1 (p<0.001) and transthyretin (p<0.038) were observed between IPA and Pseudomonas pneumonia, as was C-reactive protein (p<0.001). In summary, proteomic analysis of plasma and BAL proteins of experimental Aspergillus and Pseudomonas pneumonias demonstrates unique protein profiles with principal components and spectral regions that are shared in early infection and diverge at later stages of infection. Haptoglobin, apolipoprotein A1, transthyretin, and C-reactive protein are differentially expressed in these infections suggesting important contributions to host defense against IPA.
Collapse
Affiliation(s)
- Denise A Gonzales
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, MD 20892-1662, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
49
|
Kelly J, Kavanagh K. Caspofungin primes the immune response of the larvae of Galleria mellonella and induces a non-specific antimicrobial response. J Med Microbiol 2011; 60:189-196. [DOI: 10.1099/jmm.0.025494-0] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The echinocandins (e.g. caspofungin) function by inhibiting the synthesis of 1,3-β-glucan in the fungal cell wall. While the potent antifungal activity of caspofungin has been well characterized in mammals, this study investigated the in vivo antifungal effect of caspofungin using larvae of the insect Galleria mellonella. Caspofungin was successful in increasing the survival of larvae that were inoculated with Candida albicans 1 h before the drug was administered, particularly when a concentration of 0.19 μg ml−1 was used. Pre-injecting larvae with caspofungin also increased their survival when they were inoculated with either Staphylococcus aureus or C. albicans. Caspofungin administration resulted in an increase in the number of circulating immune cells (haemocytes), an increase in the expression of the genes encoding IMPI and transferrin, and an increase in the expression of a number of proteins (identified by liquid chromatography–mass spectrometry) some of which have immune functions. This work indicates that administration of caspofungin can increase the survival of infected G. mellonella larvae, and this is due to the antifungal properties of caspofungin and also to the ability of caspofungin to prime the insect's immune response.
Collapse
Affiliation(s)
- Judy Kelly
- Medical Mycology Unit, Department of Biology, National Institute for Cellular Biotechnology, NUI Maynooth, County Kildare, Ireland
| | - Kevin Kavanagh
- Medical Mycology Unit, Department of Biology, National Institute for Cellular Biotechnology, NUI Maynooth, County Kildare, Ireland
| |
Collapse
|
50
|
|