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Mo PM, Picard J, Gummow B. The conjunctival fungal microflora of horses in a North Queensland tropical environment and their in vitro susceptibilities to antifungal agents. Vet Res Commun 2023; 47:1641-1651. [PMID: 37022654 PMCID: PMC10485094 DOI: 10.1007/s11259-023-10119-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 03/30/2023] [Indexed: 04/07/2023]
Abstract
Fungi are ubiquitous in the environment and part of the commensal microflora on the conjunctiva of equine eyes. North Queensland, being tropical, presents an ideal environment for fungi growth. When the cornea is injured, fungi can invade the corneal stroma, resulting in keratomycosis. The objectives of this study were to determine the fungal species specific to the eyes of horses in the Townsville region; to investigate the potential risk factors associated with the presence of fungi; and to test their susceptibility to antifungals to create an empirical guide for treatment. The eyes of forty ophthalmologically normal horses from James Cook University were sampled throughout the summer months of December 2017, January 2018, and January and February 2020. Cultured fungi were identified morphologically, and their identity confirmed by comparing partial 18sRNA DNA sequences with the NCBI nucleotide database. Minimum inhibitory concentration testing of common antifungal medications was performed. Sixty-one out of eighty conjunctival samples grew fungi, and 21 different fungi genera were isolated. The most common genera were Aspergillus (18%, 26/141), Curvularia (14%,20/141), Rhodotorula (12%,17/141) and Penicillium (12%,17/141). No significant association was found between age or environmental factors and fungal culture status. Most fungi were highly susceptible to voriconazole and ketoconazole but resistant to fluconazole and amphotericin B. This adds to the body of evidence on which species of fungi are present as normal ocular microflora of horses living in tropical regions of Australia, and an avenue for treating them.
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Affiliation(s)
- Phu Mo Mo
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Queensland, Australia.
| | - Jacqueline Picard
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Queensland, Australia
| | - Bruce Gummow
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Queensland, Australia
- Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
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Weiss ZF, Little J, Hammond S. Evolution of antifungals for invasive mold infections in immunocompromised hosts, then and now. Expert Rev Anti Infect Ther 2023; 21:535-549. [PMID: 37104686 DOI: 10.1080/14787210.2023.2207821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
INTRODUCTION The current armamentarium of antifungal agents for invasive mold infections (IMI) has dramatically improved over the last 50 years. Existing therapies are, however, associated with toxicities, drug interactions, and in some cases, therapeutic failures. Novel antifungals are needed to address the increasing prevalence of IMI and the growing threat of antifungal resistance. AREAS COVERED We review the history and development of the most commonly used antifungals. We discuss the current consensus guidelines and supporting data for treatment of invasive mold infection (IMI), the role of susceptibility testing, and the niche that novel antifungals could fill. We review the current data for aspergillosis, mucormycosis, and hyalohyphomycosis. EXPERT OPINION Robust clinical trial data demonstrating the relative effectiveness of our current antifungal agents for treating IMI outside of A. fumigatus remains limited. Clinical trials are urgently needed to delineate the relationship between MICs and clinical outcomes for existing agents and to better evaluate the invitro and in-vivo aspects of antifungal synergy. Continued international multicenter collaboration and standardized clinical endpoints for trials evaluating both existing and new agents is necessary to advance the field.
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Affiliation(s)
- Zoe Freeman Weiss
- Tufts Medical Center, Division of Infectious Diseases and Geographic Medicine, Boston MA, USA
- Tufts Medical Center, Division of Pathology, Boston MA, USA
| | - Jessica Little
- Brigham and Women's Hospital, Division of Infectious Diseases, Boston MA, USA
- Dana-Farber Cancer Institute, Department of Medical Oncology, Boston, MA, USA
| | - Sarah Hammond
- Dana-Farber Cancer Institute, Department of Medical Oncology, Boston, MA, USA
- Massachusetts General Hospital, Divisions of Infectious Diseases and Hematology Oncology, Boston MA, USA
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3
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Zheng Z, Liu H, Shi Y, Liu Z, Teng H, Deng S, Wei L, Wang Y, Zhang F. Comparative transcriptome analysis reveals the resistance regulation mechanism and fungicidal activity of the fungicide phenamacril in Fusarium oxysporum. Sci Rep 2022; 12:11081. [PMID: 35773469 PMCID: PMC9247061 DOI: 10.1038/s41598-022-15188-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 06/20/2022] [Indexed: 12/21/2022] Open
Abstract
Fusarium oxysporum (Fo) is an important species complex of soil-borne pathogenic fungi that cause vascular wilt diseases of agricultural crops and some opportunistic diseases of humans. The fungicide phenamacril has been extensively reported to have antifungal activity against Fusarium graminearum and Fusarium fujikuroi. In this study, we found that the amino acid substitutions (V151A and S418T) in Type I myosin FoMyo5 cause natural low resistance to phenamacril in the plant pathogenic Fo isolates. Therefore, we compared the transcriptomes of two phenamacril-resistant Fo isolates FoII5, Fo1st and one phenamacril-sensitive isolate Fo3_a after 1 μg/mL phenamacril treatment. Among the 2728 differentially expressed genes (DEGs), 14 DEGs involved in oxidation–reduction processes and MFS transporters, were significantly up-regulated in phenamacril-resistant isolates. On the other hand, 14 DEGs involved in ATP-dependent RNA helicase and ribosomal biogenesis related proteins, showed significantly down-regulated expression in both phenamacril-resistant and -sensitive isolates. These results indicated that phenamacril not only seriously affected the cytoskeletal protein binding and ATPase activity of sensitive isolate, but also suppressed ribosome biogenesis in all the isolates. Hence, this study helps us better understand resistance regulation mechanism and fungicidal activity of phenamacril and provide reference for the development of new fungicides to control Fo.
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Affiliation(s)
- Zhitian Zheng
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huai'an, 223003, People's Republic of China.
| | - Huaqi Liu
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huai'an, 223003, People's Republic of China
| | - Yunyong Shi
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huai'an, 223003, People's Republic of China
| | - Zao Liu
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huai'an, 223003, People's Republic of China
| | - Hui Teng
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huai'an, 223003, People's Republic of China
| | - Sheng Deng
- Institute of Plant Protection, Key Lab of Food Quality and Safety of Jiangsu Province-State, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, People's Republic of China.
| | - Lihui Wei
- Institute of Plant Protection, Key Lab of Food Quality and Safety of Jiangsu Province-State, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, People's Republic of China
| | - Yunpeng Wang
- School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huai'an, 223003, People's Republic of China.
| | - Feng Zhang
- Key Laboratory of Pesticide, College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
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Shariati A, Moradabadi A, Chegini Z, Khoshbayan A, Didehdar M. An Overview of the Management of the Most Important Invasive Fungal Infections in Patients with Blood Malignancies. Infect Drug Resist 2020; 13:2329-2354. [PMID: 32765009 PMCID: PMC7369308 DOI: 10.2147/idr.s254478] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Accepted: 06/26/2020] [Indexed: 12/12/2022] Open
Abstract
In patients with hematologic malignancies due to immune system disorders, especially persistent febrile neutropenia, invasive fungal infections (IFI) occur with high mortality. Aspergillosis, candidiasis, fusariosis, mucormycosis, cryptococcosis and trichosporonosis are the most important infections reported in patients with hematologic malignancies that undergo hematopoietic stem cell transplantation. These infections are caused by opportunistic fungal pathogens that do not cause severe issues in healthy individuals, but in patients with hematologic malignancies lead to disseminated infection with different clinical manifestations. Prophylaxis and creating a safe environment with proper filters and air pressure for patients to avoid contact with the pathogens in the surrounding environment can prevent IFI. Furthermore, due to the absence of specific symptoms in IFI, rapid and accurate diagnosis reduces the mortality rate of these infections and using molecular techniques along with standard mycological methods will improve the diagnosis of disseminated fungal infection in patients with hematologic disorders. Amphotericin B products, extended-spectrum azoles, and echinocandins are the essential drugs to control invasive fungal infections in patients with hematologic malignancies, and according to various conditions of patients, different results of treatment with these drugs have been reported in different studies. On the other hand, drug resistance in recent years has led to therapeutic failures and deaths in patients with blood malignancies, which indicates the need for antifungal susceptibility tests to use appropriate therapies. Life-threatening fungal infections have become more prevalent in patients with hematologic malignancies in recent years due to the emergence of new risk factors, new species, and increased drug resistance. Therefore, in this review, we discuss the different dimensions of the most critical invasive fungal infections in patients with hematologic malignancies and present a list of these infections with different clinical manifestations, treatment, and outcomes.
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Affiliation(s)
- Aref Shariati
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Alireza Moradabadi
- Department of Medical Parasitology and Mycology, Arak University of Medical Sciences, Arak, Iran
| | - Zahra Chegini
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Amin Khoshbayan
- Student Research Committee, Iran University of Medical Sciences, Tehran, Iran
| | - Mojtaba Didehdar
- Department of Medical Parasitology and Mycology, Arak University of Medical Sciences, Arak, Iran
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Liu W, Feng R, Jiang H. Management of pulmonary Scedosporium apiospermum infection by thoracoscopic surgery in an immunocompetent woman. J Int Med Res 2020; 48:300060520931620. [PMID: 32614267 PMCID: PMC7333505 DOI: 10.1177/0300060520931620] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The Scedosporium apiospermum complex is a group of emerging opportunistic fungal pathogens that affect both immunocompromised and immunocompetent individuals, most commonly via lung infection. Although they are resistant to many antifungal agents, this group of pathogens has a favorable susceptibility profile to azoles, especially voriconazole. Here, we describe the management of S. apiospermum infection in an otherwise healthy 44-year-old woman. She had exhibited intermittent hemoptysis for 2 years before admission to our hospital. Computed tomography revealed a thin-walled and well-circumscribed cavitary lesion in the left upper lobe; the lesion was filled with consolidative opacities. Fungal culture of bronchoalveolar lavage fluid specimens revealed grayish-white mold; lactophenol cotton blue staining revealed acute angle branched septate hyaline cylindrical hyphae, characteristic of S. apiospermum. Despite voriconazole 200 mg twice daily for 8 weeks, the patient showed no improvement; thus, her left upper lobe was removed via thoracoscopic surgery. Her symptoms immediately improved and chest radiography after surgical resection showed no evidence of radiological progression or reoccurrence. This report demonstrates that S. apiospermum lung infection may not respond well to voriconazole alone in immunocompetent hosts; thus, surgery could be curative for these patients.
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Affiliation(s)
- Wei Liu
- Group of Pulmonary Disease, Department of Integrated Traditional and Western Medicine, West China Hospital of Sichuan University, Chengdu, P. R. China.,Division of Pulmonary Diseases, State Key Laboratory of Biotherapy, West China Hospital, West China School of Medicine, Sichuan University, Chengdu, P. R. China
| | - Ruizhi Feng
- Group of Pulmonary Disease, Department of Integrated Traditional and Western Medicine, West China Hospital of Sichuan University, Chengdu, P. R. China
| | - Hongli Jiang
- Group of Pulmonary Disease, Department of Integrated Traditional and Western Medicine, West China Hospital of Sichuan University, Chengdu, P. R. China
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6
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Moslem M, Mahmoudabadi AZ. The high efficacy of luliconazole against environmental and otomycosis Aspergillus flavus strains. IRANIAN JOURNAL OF MICROBIOLOGY 2020; 12:170-176. [PMID: 32494352 PMCID: PMC7244823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
BACKGROUND AND OBJECTIVES Luliconazole is currently confirmed for the topical therapy of dermatophytosis. Moreover, it is found that luliconazole has in vitro activity against some molds and yeast species. The aim of the present study was to evaluate the efficacy of luliconazole in comparison to routine used antifungals on clinical and environmental isolates of Aspergillus flavus. MATERIALS AND METHODS Thirty eight isolates of A. flavus (18 environmental and 20 clinical isolates) were detected based on morphological and microscopic features and also PCR-sequencing of β-tubulin ribosomal DNA gene. All the isolates were tested against luliconazole, voriconazole, amphotericin B and caspofungin. Minimum inhibitory concentration (MIC), MIC50, MIC90 and MIC Geometric (GM) were calculated using CLSI M38-A2 protocol for both environmental and clinical isolates. RESULTS Luliconazole with extremely low MIC range, 0.00049-0.00781 μg/mL and MICGM 0.00288 μg/mL showed very strong activity against both clinical and environmental A. flavus isolates. Moreover, voriconazole inhibited 100% of isolates at defined epidemiological cutoff values (ECV ≤ 2 μg/ml). 50% and 27.8% of clinical and environmental isolates of A. flavus, were resistant to caspofungin, respectively. Whereas, all the isolates were found to be resistant to amphotericin B. CONCLUSION The analysis of our data clearly indicated that luliconazole (with MICGM 0.00244 μg/ml for clinical and 0.00336 μg/ml for environmental isolates) had the highest in vitro activity against A. flavus strains.
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Affiliation(s)
- Maryam Moslem
- Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran,Department of Medical Mycology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Ali Zarei Mahmoudabadi
- Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran,Department of Medical Mycology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran,Corresponding author: Ali Zarei Mahmoudabadi, PhD, Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran AND Department of Medical Mycology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. Tel: +986133330074, Fax: +986133332036,
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7
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Zheng B, Yan L, Liang W, Yang Q. Paralogous Cyp51s mediate the differential sensitivity of Fusarium oxysporum to sterol demethylation inhibitors. PEST MANAGEMENT SCIENCE 2019; 75:396-404. [PMID: 29931739 DOI: 10.1002/ps.5127] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 06/18/2018] [Accepted: 06/19/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND As a soilborne fungus, Fusarium oxysporum can cause vascular wilt in numerous economically important crops. Application of antifungal drugs is the primary method for the control of F. oxysporum. Cyp51, a key enzyme of sterol biosynthesis is the main target of sterol demethylation inhibitors. RESULTS The F. oxysporum genome contains three paralogous CYP51 genes (named FoCYP51A, FoCYP51B and FoCYP51C) that putatively encode sterol 14α-demethylase enzymes. Each of the three genes was able to partially complement the Saccharomyces cerevisiae ERG11 mutant. Growth assays demonstrated that deletion mutants of FoCYP51B, but not FoCYP51A and FoCYP51C were significantly retarded in hyphal growth. Deletion of FoCYP51A (ΔFoCyp51A and ΔFoCyp51AC) led to increased sensitivity to 11 sterol demethylation inhibitors (DMIs). Interestingly, FoCYP51B deletion mutants (ΔFoCyp51B and ΔFoCyp51BC) exhibited significantly increased sensitivity to only four DMIs (two of which are in common with the 11 DMIs mentioned earlier). Deletion of FoCYP51C did not change DMI sensitivity of F. oxysporum. None of the three FoCYP51s are involved in F. oxysporum virulence. The sensitivity of F. oxysporum isolates increased significantly when subjected to a mixture of different subgroups of DMIs classified based on the different sensitivities of FoCYP51 mutants to DMIs compared to the individual components. CONCLUSIONS FoCYP51A and FoCYP51B are responsible for sensitivity to different azoles. These findings have direct implications for fungicide application strategies of plant and human diseases caused by F. oxysporum. © 2018 Society of Chemical Industry.
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Affiliation(s)
- Bangxian Zheng
- The Key Laboratory of Integrated Crop Pest Management of Shandong Province, Department of Plant Pathology, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, P. R. China
| | - Leiyan Yan
- Ningbo Academy of Agricultural Sciences, Institute of Vegetables, Ningbo, P. R. China
| | - Wenxing Liang
- The Key Laboratory of Integrated Crop Pest Management of Shandong Province, Department of Plant Pathology, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, P. R. China
| | - Qianqian Yang
- The Key Laboratory of Integrated Crop Pest Management of Shandong Province, Department of Plant Pathology, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, P. R. China
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8
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Zainul-Abidin S, Amanatullah DF, Anderson MB, Austin M, Barretto JM, Battenberg A, Bedard NA, Bell K, Blevins K, Callaghan JJ, Cao L, Certain L, Chang Y, Chen JP, Cizmic Z, Coward J, DeMik DE, Diaz-Borjon E, Enayatollahi MA, Feng JE, Fernando N, Gililland JM, Goodman S, Goodman S, Greenky M, Hwang K, Iorio R, Karas V, Khan R, Kheir M, Klement MR, Kunutsor SK, Limas R, Morales Maldonado RA, Manrique J, Matar WY, Mokete L, Nung N, Pelt CE, Pietrzak JRT, Premkumar A, Rondon A, Sanchez M, Novaes de Santana C, Sheth N, Singh J, Springer BD, Tay KS, Varin D, Wellman S, Wu L, Xu C, Yates AJ. General Assembly, Prevention, Host Related General: Proceedings of International Consensus on Orthopedic Infections. J Arthroplasty 2019; 34:S13-S35. [PMID: 30360983 DOI: 10.1016/j.arth.2018.09.050] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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9
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Pulmonary Infection Secondary to Chrysosporium zonatum in an Immunocompetent Man. Ann Am Thorac Soc 2018; 13:757-8. [PMID: 27144802 DOI: 10.1513/annalsats.201601-083le] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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10
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Dananjaya S, Erandani W, Kim CH, Nikapitiya C, Lee J, De Zoysa M. Comparative study on antifungal activities of chitosan nanoparticles and chitosan silver nano composites against Fusarium oxysporum species complex. Int J Biol Macromol 2017; 105:478-488. [DOI: 10.1016/j.ijbiomac.2017.07.056] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 07/04/2017] [Accepted: 07/10/2017] [Indexed: 01/22/2023]
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11
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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.
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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
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de J. Treviño-Rangel R, González GM. Susceptibility Testing Agents of Subcutaneous Mycoses (Sporotrichosis and Chromoblastomycosis). CURRENT FUNGAL INFECTION REPORTS 2015. [DOI: 10.1007/s12281-015-0232-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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13
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Schäfer K, Di Pietro A, Gow NAR, MacCallum D. Murine model for Fusarium oxysporum invasive fusariosis reveals organ-specific structures for dissemination and long-term persistence. PLoS One 2014; 9:e89920. [PMID: 24587124 PMCID: PMC3937399 DOI: 10.1371/journal.pone.0089920] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 01/28/2014] [Indexed: 12/04/2022] Open
Abstract
The soil-borne plant pathogen Fusarium oxysporum causes life-threatening invasive fusariosis in immunocompromised individuals. The mechanism of infection in mammalian hosts is largely unknown. In the present study we show that the symptoms of disseminated fusariosis caused by F. oxysporum in immunosuppressed mice are remarkably similar to those reported in humans. Distinct fungal structures were observed inside the host, depending on the infected organ. Invasive hyphae developed in the heart and kidney, causing massive colonization of the organs. By contrast, chlamydospore-like survival structures were found in lung, spleen and liver. Systemically infected mice also developed skin and eye infections, as well as thrombosis and necrosis in the tail. We further show that F. oxysporum can disseminate and persist in the organs of immunocompetent animals, and that these latent infections can lead to lethal systemic fusariosis if the host is later subjected to immunosuppressive treatment.
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Affiliation(s)
- Katja Schäfer
- Departamento de Genética, Universidad de Córdoba, Córdoba, Spain
- * E-mail:
| | | | - Neil A. R. Gow
- Aberdeen Fungal Group, Institute of Medical Sciences, Aberdeen, United Kingdom
| | - Donna MacCallum
- Aberdeen Fungal Group, Institute of Medical Sciences, Aberdeen, United Kingdom
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14
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Susceptibility breakpoints for amphotericin B and Aspergillus species in an in vitro pharmacokinetic-pharmacodynamic model simulating free-drug concentrations in human serum. Antimicrob Agents Chemother 2014; 58:2356-62. [PMID: 24514094 DOI: 10.1128/aac.02661-13] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Although conventional amphotericin B was for many years the drug of choice and remains an important agent against invasive aspergillosis, reliable susceptibility breakpoints are lacking. Three clinical Aspergillus isolates (Aspergillus fumigatus, Aspergillus flavus, and Aspergillus terreus) were tested in an in vitro pharmacokinetic-pharmacodynamic model simulating the biphasic 24-h time-concentration profile of free amphotericin B concentrations in human serum with free peak concentrations (fCmax) of 0.1, 0.3, 0.6, 1.2, and 2.4 mg/liter administered once daily. Drug concentrations were measured with a bioassay, and fungal growth was monitored for 72 h with galactomannan production. The fCmax/MIC corresponding to half-maximal activity (P50) was determined for each species, and the percentage of target attainment was calculated for different MICs for the standard (1 mg/kg of body weight) and a lower (0.6-mg/kg) dose of amphotericin B with Monte Carlo simulation analysis. The fCmax/MICs (95% confidence intervals) corresponding to P50 were 0.145 (0.133 to 0.158), 0.371 (0.283 to 0.486), and 0.41 (0.292 to 0.522) for A. fumigatus, A. flavus, and A. terreus, respectively. The median percentages of P50 attainment were ≥88%, 47%, and 0% for A. fumigatus isolates with MICs of ≤0.5, 1, and ≥2 mg/liter, respectively, and ≥81%, 24%, and 0% and ≥75%, 15%, and 0% for A. flavus and A. terreus isolates with MICs of ≤0.25, 0.5, and ≥1 mg/liter, respectively. The lower dose of 0.6 mg/kg would retain efficacy for A. fumigatus, A. flavus, and A. terreus isolates with MICs of ≤0.25, ≤0.125, and ≤0.125 mg/liter, respectively. The susceptibility, intermediate susceptibility, and resistance breakpoints of ≤0.5, 1, and ≥2 mg/liter for A. fumigatus and ≤0.25, 0.5, and ≥1 mg/liter for A. flavus and A. terreus were determined for conventional amphotericin B with a pharmacokinetic-pharmacodynamic model simulating free-drug serum concentrations.
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Ashbee HR, Barnes RA, Johnson EM, Richardson MD, Gorton R, Hope WW. Therapeutic drug monitoring (TDM) of antifungal agents: guidelines from the British Society for Medical Mycology. J Antimicrob Chemother 2013; 69:1162-76. [PMID: 24379304 DOI: 10.1093/jac/dkt508] [Citation(s) in RCA: 463] [Impact Index Per Article: 42.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The burden of human disease related to medically important fungal pathogens is substantial. An improved understanding of antifungal pharmacology and antifungal pharmacokinetics-pharmacodynamics has resulted in therapeutic drug monitoring (TDM) becoming a valuable adjunct to the routine administration of some antifungal agents. TDM may increase the probability of a successful outcome, prevent drug-related toxicity and potentially prevent the emergence of antifungal drug resistance. Much of the evidence that supports TDM is circumstantial. This document reviews the available literature and provides a series of recommendations for TDM of antifungal agents.
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Affiliation(s)
- H Ruth Ashbee
- Mycology Reference Centre, Department of Microbiology, Leeds Teaching Hospitals NHS Trust, Leeds LS1 3EX, UK
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Antifungal use and therapeutic monitoring of plasma concentrations of itraconazole in heart and lung transplantation patients. Ther Drug Monit 2013. [PMID: 23188182 DOI: 10.1097/ftd.0b013e318275fe69] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The prophylactic use of itraconazole has dramatically reduced the incidence of fungal infections in patients after solid-organ transplantation. To further reduce this incidence, it has been suggested that plasma concentrations of itraconazole be monitored and maintained above a putative minimum target concentration of 500 ng/mL. METHODS A retrospective audit was undertaken of patients who had had a heart or lung transplant over a 14-month period (between January 1, 2010 and March 31, 2011). The itraconazole prophylaxis regimen (dose, time of last dose, time of blood collection) and plasma concentrations were recorded together with the use of concomitant antacid medication. Details of breakthrough fungal infections were documented. RESULTS Eighty-four heart or lung organ transplantations were undertaken in the study period; 57 were treated prophylactically with itraconazole. Plasma concentrations of itraconazole were monitored in 56% (n = 32) of these cases. Considerable interpatient (range, 50-2000 ng/mL) and intrapatient variability in plasma concentrations was observed. The putative target was not achieved consistently in the majority of cases. All patients were taking a proton pump inhibitor. Six of the cohort developed an invasive fungal infection. None of the 3 patients for whom plasma concentrations were monitored was above the target concentration. CONCLUSIONS Further clinical studies, involving monitoring of the active metabolite and attention to the importance of the stereoisomers of itraconazole, may give better insight into the appropriateness of the currently suggested minimum target concentration, whose validity remains uncertain. Formulations with improved absorption characteristics could reduce the variability of absorption with the goal of further reducing the incidence of infrequent, but life-threatening, invasive fungal infections.
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Guarro J. Fusariosis, a complex infection caused by a high diversity of fungal species refractory to treatment. Eur J Clin Microbiol Infect Dis 2013; 32:1491-500. [DOI: 10.1007/s10096-013-1924-7] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 07/03/2013] [Indexed: 11/30/2022]
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Carrillo-Muñoz AJ, Quindós G, Del Valle O, Hernández-Molina JM, Santos P. Antifungal Activity of Amphotericin B and Itraconazole against Filamentous Fungi: Comparison of the Sensititre Yeast OneŴ and NCCLS M38-A Reference Methods. J Chemother 2013; 16:468-73. [PMID: 15565914 DOI: 10.1179/joc.2004.16.5.468] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
The susceptibilities of 81 clinical isolates of Aspergillus spp., Fusarium spp., and Scedosporium spp., to amphotericin B and itraconazole were determined by the colorimetric microdilution method Sensititre and the reference microdilution method of NCCLS standard M38-A for filamentous fungi. No major discrepancies were found and agreement ranged between 86.4% to 84% and 69.1% to 86.4% for amphotericin B and itraconazole respectively at 48 h and 72 h of incubation by using the recommended endpoints. Within two two-fold dilutions, high levels of agreement were found in general for amphotericin B at 48 or 72 h (86.4 to 87.7%) and itraconazole (91.4 to 93.8%). Relatively better agreement was found for itraconazole at 72 h of incubation and 48 for amphotericin B.
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Drago M, Scaltrito MM, Cariani L, Morace G. In VitroTesting ofAspergillus fumigatusClinical Isolates for Susceptibility to Voriconazole, Amphotericin B and Itraconazole: Comparison of Sensititre versus NCCLS M38-A Using Two Different Inocula. J Chemother 2013; 16:474-8. [PMID: 15565915 DOI: 10.1179/joc.2004.16.5.474] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Voriconazole, amphotericin B and itraconazole were tested in vitro against 18 strains of Aspergillus fumigatus isolated from cystic fibrosis patients. Susceptibility was tested with the broth microdilution method (M38-A protocol-NCCLS). Results of this reference method were compared with those of an experimental commercial microdilution broth method (Sensititre). Two different inocula, prepared from 2- and 7-day cultures, were used. Minimum inhibitory concentrations (MICs) of the reference method ranged from 0.25 to 2 microg/ml for voriconazole, 0.06 to 1 microg/ml for amphotericin B, 0.016 to >16 microg/ml for itraconazole. There were no significant differences in the MIC ranges or MIC90 values obtained with the two testing methods or with the two types of inocula. These findings confirm the good in vitro activity of voriconazole, itraconazole and amphotericin B against A. fumigatus. They also indicate that reliable susceptibility data can be generated more rapidly by commercial systems and use of 2-day cultures for inoculum preparation.
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Affiliation(s)
- M Drago
- Istituto di Microbiologia, Università degli Studi di Milano, Italy
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Identification of the cell targets important for propolis-induced cell death in Candida albicans. Fungal Genet Biol 2013; 60:74-86. [PMID: 23856128 DOI: 10.1016/j.fgb.2013.07.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Revised: 06/29/2013] [Accepted: 07/02/2013] [Indexed: 11/22/2022]
Abstract
Candida albicans is the most common fungal pathogen of humans, forming both commensal and opportunistic pathogenic interactions, causing a variety of skin and soft tissue infections in healthy people. In immunocompromised patients C. albicans can result in invasive, systemic infections that are associated with a high incidence of mortality. Propolis is a complex mixture of several resinous substances which are collected from plants by bees. Here, we demonstrated the fungicidal activity of propolis against all three morphogenetic types of C. albicans and that propolis-induced cell death was mediated via metacaspase and Ras signaling. To identify genes that were involved in propolis tolerance, we screened ~800 C. albicans homozygous deletion mutants for decreased tolerance to propolis. Fifty-one mutant strains were identified as being hypersensitive to propolis including seventeen genes involved in cell adhesion, biofilm formation, filamentous growth, phenotypic switching and pathogenesis (HST7, GIN4, VPS34, HOG1, ISW2, SUV3, MDS3, HDA2, KAR3, YHB1, NUP85, CDC10, MNN9, ACE2, FKH2, and SNF5). We validated these results by showing that propolis inhibited the transition from yeast-like to hyphal growth. Propolis was shown to contain compounds that conferred fluorescent properties to C. albicans cells. Moreover, we have shown that a topical pharmaceutical preparation, based upon propolis, was able to control C. albicans infections in a mouse model for vulvovaginal candidiasis. Our results strongly indicate that propolis could be used as a strategy for controlling candidiasis.
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De Gannes V, Eudoxie G, Hickey WJ. Insights into fungal communities in composts revealed by 454-pyrosequencing: implications for human health and safety. Front Microbiol 2013; 4:164. [PMID: 23785368 PMCID: PMC3682178 DOI: 10.3389/fmicb.2013.00164] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 06/03/2013] [Indexed: 01/18/2023] Open
Abstract
Fungal community composition in composts of lignocellulosic wastes was assessed via 454-pyrosequencing of ITS1 libraries derived from the three major composting phases. Ascomycota represented most (93%) of the 27,987 fungal sequences. A total of 102 genera, 120 species, and 222 operational taxonomic units (OTUs; >97% similarity) were identified. Thirty genera predominated (ca. 94% of the sequences), and at the species level, sequences matching Chaetomium funicola and Fusarium oxysporum were the most abundant (26 and 12%, respectively). In all composts, fungal diversity in the mature phase exceeded that of the mesophilic phase, but there was no consistent pattern in diversity changes occurring in the thermophilic phase. Fifteen species of human pathogens were identified, eight of which have not been previously identified in composts. This study demonstrated that deep sequencing can elucidate fungal community diversity in composts, and that this information can have important implications for compost use and human health.
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Affiliation(s)
- Vidya De Gannes
- Department of Food Production, Faculty of Food and Agriculture, University of the West Indies, St. Augustine Campus St. Augustine, Republic of Trinidad and Tobago
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Single-dose pharmacodynamics of amphotericin B against Aspergillus species in an in vitro pharmacokinetic/pharmacodynamic model. Antimicrob Agents Chemother 2013; 57:3713-8. [PMID: 23716054 DOI: 10.1128/aac.02484-12] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Conventional MIC testing of amphotericin B results in narrow MIC ranges challenging the detection of resistant strains. In order to discern amphotericin B pharmacodynamics, the in vitro activity of amphotericin B was studied against Aspergillus isolates with the same MICs by using a new in vitro pharmacokinetic/pharmacodynamic (PK/PD) model that simulates amphotericin B human plasma levels. Clinical isolates of Aspergillus fumigatus, A. terreus, and A. flavus with the same Clinical and Laboratory Standards Institute modal MICs of 1 mg/liter were exposed to amphotericin B concentrations following the plasma concentration-time profile after single-bolus administration with C(max) values of 0.6, 1.2, 2.4, and 4.8 mg/liter. Fungal growth was monitored for up to 72 h based on galactomannan production. Complete growth inhibition was observed only against A. fumigatus with amphotericin B with a Cmax of ≥ 2.4 mg/liter. At the lower C(max) values 0.6 and 1.2 mg/liter, significant growth delays of 34 and 52 h were observed, respectively (P < 0.001). For A. flavus, there was no complete inhibition but a progressive growth delay of 1 to 50 h at an amphotericin B C(max) of 0.6 to 4.8 mg/liter (P < 0.001). For A. terreus, the growth delay was modest (up to 8 h) at all C(max)s (P < 0.05). The C(max) (95% confidence interval) associated with 50% activity for A. fumigatus was 0.60 (0.49 to 0.72) mg/liter, which was significantly lower than for A. flavus 3.06 (2.46 to 3.80) mg/liter and for A. terreus 7.90 (5.20 to 12.29) mg/liter (P < 0.001). A differential in vitro activity of amphotericin B was found among Aspergillus species despite the same MIC in the order A. fumigatus > A. flavus > A. terreus in the in vitro PK/PD model, possibly reflecting the different concentration- and time-dependent inhibitory/killing activities amphotericin B exerted against these species.
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Inhibitory and fungicidal effects of antifungal drugs against Aspergillus species in the presence of serum. Antimicrob Agents Chemother 2013; 57:1625-31. [PMID: 23318807 DOI: 10.1128/aac.01573-12] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Given the high protein binding rates of antifungal drugs and the effect of serum proteins on Aspergillus growth, we investigated the in vitro pharmacodynamics of amphotericin B, voriconazole, and three echinocandins in the presence of human serum, assessing both inhibitory and fungicidal effects. In vitro inhibitory (IC) and fungicidal (FC) concentrations against 5 isolates of Aspergillus fumigatus, Aspergillus flavus, and Aspergillus terreus were determined with a CLSI M38-A2-based microdilution method using the XTT methodology after 48 h of incubation at 35 °C with a medium supplemented with 50% human serum. In the presence of serum, the IC and FC of amphotericin B and the IC of echinocandins were increased (1.21- to 13.44-fold), whereas voriconazole IC and FC were decreased (0.22- to 0.90-fold). The amphotericin B and voriconazole FC/IC ratios did not change significantly (0.59- to 2.33-fold) in the presence of serum, indicating that the FC increase was due to the IC increase. At echinocandin concentrations above the minimum effective concentration (MEC), fungal growth was reduced by 10 to 50% in the presence of human serum, resulting in complete inhibition of growth for some isolates. Thus, the in vitro activities of amphotericin B and echinocandins were reduced, whereas that of voriconazole was enhanced, in the presence of serum. These changes could not be predicted by the percentage of protein binding, indicating that other factors and/or secondary mechanisms may account for the observed in vitro activities of antifungal drugs against Aspergillus species in the presence of serum.
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Mirkov I, Stosic-Grujicic S, Kataranovski M. Host immune defense against Aspergillus fumigatus: insight from experimental systemic (disseminated) infection. Immunol Res 2012; 52:120-6. [PMID: 22388638 DOI: 10.1007/s12026-012-8274-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Model of systemic Aspergillus fumigatus infection induced by intravenous application of conidia is suitable for studying important aspects of invasive aspergillosis including relationship between infection and mortality, dissemination of infection and immune mechanisms involved in host resistance to this fungus. Use of this model allows the investigation of both innate and adaptive immune response characteristics in resistant/susceptible host, and investigating the contribution of genetic background and cytokine gene deficiency improves the knowledge of the diversity of mechanisms of immune response to Aspergillus infection. Studying of various aspects of systemic aspergillosis contributes to development of antifungal drugs.
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Affiliation(s)
- I Mirkov
- Department of Ecology, Institute for Biological Research Sinisa Stankovic, University of Belgrade, Bulevar Despota Stefana 142, 11060 Belgrade, Serbia
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Gamaletsou MN, Sipsas NV, Roilides E, Walsh TJ. Rhino-Orbital-Cerebral Mucormycosis. Curr Infect Dis Rep 2012; 14:423-34. [DOI: 10.1007/s11908-012-0272-6] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Colozza C, Posteraro B, Santilli S, De Carolis E, Sanguinetti M, Girmenia C. In vitro activities of amphotericin B and AmBisome against Aspergillus isolates recovered from Italian patients treated for haematological malignancies. Int J Antimicrob Agents 2012; 39:440-3. [DOI: 10.1016/j.ijantimicag.2012.01.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Revised: 01/19/2012] [Accepted: 01/20/2012] [Indexed: 11/29/2022]
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27
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Rudramurthy SM, Chakrabarti A, Geertsen E, Mouton JW, Meis JF. In vitro activity of isavuconazole against 208 Aspergillus flavus isolates in comparison with 7 other antifungal agents: assessment according to the methodology of the European Committee on Antimicrobial Susceptibility Testing. Diagn Microbiol Infect Dis 2011; 71:370-7. [DOI: 10.1016/j.diagmicrobio.2011.08.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 08/04/2011] [Accepted: 08/04/2011] [Indexed: 11/29/2022]
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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.
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Rapid identification of Pseudallescheria and Scedosporium strains by using rolling circle amplification. Appl Environ Microbiol 2011; 78:126-33. [PMID: 22057865 DOI: 10.1128/aem.05280-11] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Pseudallescheria boydii complex, comprising environmental pathogens with Scedosporium anamorphs, has recently been subdivided into five main species: Scedosporium dehoogii, S. aurantiacum, Pseudallescheria minutispora, P. apiosperma, and P. boydii, while the validity of some other taxa is being debated. Several Pseudallescheria and Scedosporium species are indicator organisms of pollution in soil and water. Scedosporium dehoogii in particular is enriched in soils contaminated by aliphatic hydrocarbons. In addition, the fungi may cause life-threatening infections involving the central nervous system in severely impaired patients. For screening purposes, rapid and economic tools for species recognition are needed. Our aim is to establish rolling circle amplification (RCA) as a screening tool for species-specific identification of Pseudallescheria and Scedosporium. With this aim, a set of padlock probes was designed on the basis of the internal transcribed spacer (ITS) region, differing by up to 13 fixed mutations. Padlock probes were unique as judged from sequence comparison by BLAST search in GenBank and in dedicated research databases at CBS (Centraalbureau voor Schimmelcultures Fungal Biodiversity Centre). RCA was applied as an in vitro tool, tested with pure DNA amplified from cultures. The species-specific padlock probes designed in this study yielded 100% specificity. The method presented here was found to be an attractive alternative to identification by restriction fragment length polymorphism (RFLP) or sequencing. The rapidity (<1 day), specificity, and low costs make RCA a promising screening tool for environmentally and clinically relevant fungi.
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Soundararajan P, Sakkiah S, Sivanesan I, Lee KW, Jeong BR. Macromolecular Docking Simulation to Identify Binding Site of FGB1 for Antifungal Compounds. B KOREAN CHEM SOC 2011. [DOI: 10.5012/bkcs.2011.32.10.3675] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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A case of rhinoorbital mucormycosis in a leukemic patient with a literature review from Turkey. Mycopathologia 2011; 172:397-405. [PMID: 21761152 DOI: 10.1007/s11046-011-9449-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Accepted: 07/03/2011] [Indexed: 12/18/2022]
Abstract
Mucormycosis (Zygomycosis) is a rare, invasive, opportunistic fungal infection of the paranasal sinuses, caused by a fungus of the order Mucorales. We report a case of rhinoorbital mucormycosis caused by Rhizopus oryzae in an acute lymphoblastic leukemia patient and review the 79 Mucormycosis cases reported in the last decade from Turkey. In our case, the diagnosis was made with endoscopic appearance, computerized tomography of the paranasal sinuses, and culture of the surgical materials. Following aggressive surgical debridement and parenteral amphotericin B therapy, the patient recovered completely. In Turkish literature, rhinocerebral manifestations were the most common form of the mucormycosis (64 cases), followed by pulmonary form (6 cases). The most common risk factor was hematologic malignancies (32 cases) and diabetes mellitus (32 cases), similar to those reported from the rest of the world. The etiologic agents responsible for the review cases were Rhizopus sp., Mucor spp., Rhizomucor spp., Rhizopus oryzae, Mucor circinelloides, and Lichtheimia corymbifera. Although various treatment modalities were used, amphotericin B was the mainstay of therapy. Mortality rate was found to be 49.4% in review cases. It seems that strong clinical suspicion and early diagnosis, along with aggressive antifungal therapy and endoscopic sinus surgery, have great importance for better prognosis in mucormycosis.
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Shapiro RS, Robbins N, Cowen LE. Regulatory circuitry governing fungal development, drug resistance, and disease. Microbiol Mol Biol Rev 2011; 75:213-67. [PMID: 21646428 PMCID: PMC3122626 DOI: 10.1128/mmbr.00045-10] [Citation(s) in RCA: 374] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Pathogenic fungi have become a leading cause of human mortality due to the increasing frequency of fungal infections in immunocompromised populations and the limited armamentarium of clinically useful antifungal drugs. Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus are the leading causes of opportunistic fungal infections. In these diverse pathogenic fungi, complex signal transduction cascades are critical for sensing environmental changes and mediating appropriate cellular responses. For C. albicans, several environmental cues regulate a morphogenetic switch from yeast to filamentous growth, a reversible transition important for virulence. Many of the signaling cascades regulating morphogenesis are also required for cells to adapt and survive the cellular stresses imposed by antifungal drugs. Many of these signaling networks are conserved in C. neoformans and A. fumigatus, which undergo distinct morphogenetic programs during specific phases of their life cycles. Furthermore, the key mechanisms of fungal drug resistance, including alterations of the drug target, overexpression of drug efflux transporters, and alteration of cellular stress responses, are conserved between these species. This review focuses on the circuitry regulating fungal morphogenesis and drug resistance and the impact of these pathways on virulence. Although the three human-pathogenic fungi highlighted in this review are those most frequently encountered in the clinic, they represent a minute fraction of fungal diversity. Exploration of the conservation and divergence of core signal transduction pathways across C. albicans, C. neoformans, and A. fumigatus provides a foundation for the study of a broader diversity of pathogenic fungi and a platform for the development of new therapeutic strategies for fungal disease.
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Affiliation(s)
| | | | - Leah E. Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
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Shivaprakash MR, Geertsen E, Chakrabarti A, Mouton JW, Meis JF. In vitro susceptibility of 188 clinical and environmental isolates of Aspergillus flavus for the new triazole isavuconazole and seven other antifungal drugs. Mycoses 2011; 54:e583-9. [PMID: 21518026 DOI: 10.1111/j.1439-0507.2010.01996.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Recently isavuconazole, an experimental triazole agent, was found to be active against Aspergillus species. As Aspergillus flavus is the second-most common Aspergillus species isolated from human infection and the fungus has not been widely tested against the drug, we studied a large collection of clinical (n = 178) and environmental (n = 10) strains of A. flavus against isavuconazole and compared the results with seven other Aspergillus-active antifungal agents (some of them triazoles, others echinocandins or polyene antifungals: voriconazole, posaconazole, itraconazole, caspofungin, anidulafungin, micafungin and amphotericin B) using Clinical and Laboratory Standards Institute methods. Strains with high minimal inhibitory concentrations (MICs) were tested by E-test as well. The strains were collected from two different geographical locations (India and the Netherlands). Three isolates (1.6%) had high MIC (2 mg l(-1) by microbroth dilution and 8 mg l(-1) by E-test) for amphotericin B. Isavuconazole showed good activity against A. flavus strains with MIC(50) and MIC(90) values of 1 mg l(-1). As compared with voriconazole (the drug recommended for primary therapy of aspergillosis), isavuconazole had better activity (99.5% of strains had MIC of ≤ 1 mg l(-1) for isavuconazole, compared to 74% of strains with same MIC for voriconazole). All strains were, following recently proposed clinical breakpoints, susceptible for the triazoles tested except three strains, which had MICs of 4 mg l(-1) for voriconazole. Testing these strains with high MIC by E-test, gave results of 0.5-2 mg l(-1). Posaconazole had the lowest MIC(50) and MIC(90) of 0.125 mg l(-1) and 0.25 mg l(-1), respectively. Among echinocandins, 97% of strains had a minimum effective concentration (MEC) of ≤ 0.5 mg l(-1) for caspofungin, and all strains had a MEC of ≤ 0.016 mg l(-1) and ≤ 0.125 mg l(-1) for anidulafungin and micafungin, respectively.
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Affiliation(s)
- M R Shivaprakash
- Mycology Division, Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
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Guarro J. Lessons from animal studies for the treatment of invasive human infections due to uncommon fungi. J Antimicrob Chemother 2011; 66:1447-66. [PMID: 21493649 DOI: 10.1093/jac/dkr143] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Clinical experience in the management of opportunistic infections, especially those caused by less common fungi, is, due to their rarity, very scarce; therefore, the most effective treatments remain unknown. The ever-increasing numbers of fungal infections due to opportunistic fungi have repeatedly proven the limitations of the antifungal armamentarium. Moreover, some of these fungi, such as Fusarium spp. or Scedosporium spp., are innately resistant to almost all the available antifungal drugs, which makes the development of new and effective therapies a high priority. Since it is difficult to conduct randomized clinical trials in these uncommon mycoses, the use of animal models is a good alternative for evaluating new therapies. This is an extensive review of the numerous studies that have used animal models for this purpose against a significant number of less common fungi. A table describing the different studies performed on the efficacy of the different drugs tested is included for each fungal species. In addition, there is a summary table showing the conclusions that can be derived from the analysis of the studies and listing the drugs that showed the best results. Considering the wide variability in the response to the antifungals that the different strains of a given species can show, the table highlights the drugs that showed positive results using at least two parameters for evaluating efficacy against at least two different strains without showing any negative results. These data can be very useful for guiding the treatment of rare infections when there is very little experience or when controversial results exist, or when treatment fails.
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Affiliation(s)
- Josep Guarro
- Mycology Unit, Medical School, IISPV, Rovira i Virgili University, 43201 Reus, Spain.
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Elad D. Infections caused by fungi of the Scedosporium/Pseudallescheria complex in veterinary species. Vet J 2011; 187:33-41. [DOI: 10.1016/j.tvjl.2010.05.028] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2010] [Revised: 05/17/2010] [Accepted: 05/23/2010] [Indexed: 11/28/2022]
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Identification of Paecilomyces variotii in clinical samples and settings. J Clin Microbiol 2010; 48:2754-61. [PMID: 20519470 DOI: 10.1128/jcm.00764-10] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Paecilomyces variotii is a commonly occurring species in air and food, but it is also associated with many types of human infections and is among the emerging causative agents of opportunistic mycoses in immunocompromised hosts. Paecilomyces can cause hyalohyphomycosis, and two species, Paecilomyces lilacinus and P. variotii, are the most frequently encountered organisms. In the present study, a set of 34 clinical isolates morphologically identified as P. variotii or P. lilacinus were formally identified by sequencing intergenic transcribed spacer regions 1 and 2 (including 5.8S rDNA) and a part of the beta-tubulin gene. Three isolates were identified as P. lilacinus, and five of the presumptive P. variotii isolates did not belong to the genus Paecilomyces but were identified as Talaromyces eburneus (anamorph, Geosmithia argillacea) or Hamigera avellanea (anamorph, Merimbla ingelheimense). Applying the most recent taxonomy, we found that the clinical P. variotii isolates could be identified as P. variotii sensu stricto (14 strains), P. formosus (11 strains), and P. dactylethromorphus (1 strain). These data indicate that P. formosus occurs in clinical samples as commonly as P. variotii. Susceptibility tests showed that the antifungal susceptibility profiles of P. variotii, P. formosus, and P. dactylethromorphus are similar and that all strains tested were susceptible to amphotericin B in vitro. P. lilanicus, T. eburneus, and H. avellanea had different susceptibility profiles; and flucytosine and voriconazole were the least active of the antifungal drugs tested against these species. Our results indicate that correct species identification is important to help guide appropriate antifungal therapy.
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Pearce JW, Giuliano EA, Moore CP. In vitro susceptibility patterns of Aspergillus and Fusarium species isolated from equine ulcerative keratomycosis cases in the midwestern and southern United States with inclusion of the new antifungal agent voriconazole. Vet Ophthalmol 2009; 12:318-24. [PMID: 19751493 DOI: 10.1111/j.1463-5224.2009.00721.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To evaluate and compare the in vitro susceptibility of Aspergillus and Fusarium spp. isolated from horses with ulcerative keratomycosis, address regional differences in equine keratomycosis isolates, and provide susceptibility data to update prior studies. ANIMAL STUDIED Fourteen horses with ulcerative keratomycosis. PROCEDURES Banked fungal isolates from equine corneal ulcers (eight Aspergillus spp. and six Fusarium spp.) were identified at The University of Texas Health Science Center at San Antonio. In vitro minimum inhibitory concentration and susceptibility to natamycin, fluconazole, itraconazole, voriconazole, ketoconazole, and miconazole were determined for each isolate. RESULTS Fungi were significantly more susceptible to voriconazole than to natamycin, itraconazole, fluconazole, and ketoconazole, but miconazole susceptibility did not differ significantly from voriconazole. Aspergillus spp. were most susceptible to voriconazole, miconazole, and itraconazole, which were significantly better to fluconazole and ketoconazole. Fusarium spp. susceptibility was greatest to natamycin and voriconazole and lowest to itraconazole and ketoconazole. Fusarium spp. were significantly less susceptible to itraconazole and ketoconazole compared to natamycin. No significant differences in susceptibility were found when isolates from Florida were compared with isolates from other states. CONCLUSIONS AND CLINICAL RELEVANCE Based on in vitro evidence, voriconazole appears to be the most effective antifungal for initial treatment of equine keratomycosis in the midwestern and southern United States. Results are comparable with previous studies in that isolated fungi from equine keratomycosis cases showed consistently poor susceptibility to fluconazole. Organisms isolated in different geographic locations of the midwestern and southern United States appeared to have similar patterns of antifungal susceptibility.
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Affiliation(s)
- Jacqueline W Pearce
- Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri-Columbia, Columbia, MO 65211, USA.
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Kara IO, Tasova Y, Uguz A, Sahin B. Mucormycosis-associated fungal infections in patients with haematologic malignancies. Int J Clin Pract 2009; 63:134-9. [PMID: 17362481 DOI: 10.1111/j.1742-1241.2006.01145.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Among patients with haematologic disorders, mucormycosis most commonly occurs in those with acute leukaemia or lymphoma who have developed neutropenia due to malignancy or to chemotherapy, and in transplanted patients receiving immunosuppressive treatment. Here, we aim to present a retrospective study conducted over a 5-year period (2001-2005). The study included 20 patients with haematologic malignancies with a proven mucormycosis admitted in Medical Oncology Divisions in Cukurova University Hospital. The most frequent sites of infection were paranasal sinuses (95%) and lung (5%). Antifungal treatment was empirically administered in 18 (90%) patients; 18 patients underwent radical surgical debridement (90%). The therapy was successful for only eight patients (40%). Eleven patients died within 1 months of the diagnosis of fungal infection: the cause of death was only by mucormycosis in four patients (36.6%), mucormucosis and systematic inflamatuar response syndrome (SIRS) in two patients (18.2%) and progression of haematologic disease in five patients (45.5%). At univariate analysis, the factors that correlated with a positive outcome from infection were the following: amphotericin B treatment, neutrophil recovery from postchemotherapy aplasia. At multivariate analysis, the factors that significantly correlated with recovery from infection were the liposomal amphotericin B treatment (p = 0.026), doses of L-AmB (p = 0.008) and the length of the treatment (p = 0.01), respectively. It seems to have increased in recent years. Although a reduction of mortality has been observed recently, the mortality rate still remains high. Extensive and aggressive diagnostic and therapeutic procedures are essential to improve the prognosis in these patients.
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Affiliation(s)
- I O Kara
- Department of Medical Oncology, Faculty of Medicine, Cukurova University, Turkey.
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EUCAST Technical Note on the method for the determination of broth dilution minimum inhibitory concentrations of antifungal agents for conidia–forming moulds. Clin Microbiol Infect 2008; 14:982-4. [DOI: 10.1111/j.1469-0691.2008.02086.x] [Citation(s) in RCA: 295] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Bioluminescent Aspergillus fumigatus, a new tool for drug efficiency testing and in vivo monitoring of invasive aspergillosis. Appl Environ Microbiol 2008; 74:7023-35. [PMID: 18820063 DOI: 10.1128/aem.01288-08] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aspergillus fumigatus is the main cause of invasive aspergillosis in immunocompromised patients, and only a limited number of drugs for treatment are available. A screening method for new antifungal compounds is urgently required, preferably an approach suitable for in vitro and in vivo studies. Bioluminescence imaging is a powerful tool to study the temporal and spatial resolutions of the infection and the effectiveness of antifungal drugs. Here, we describe the construction of a bioluminescent A. fumigatus strain by fusing the promoter of the glyceraldehyde-3-phosphate dehydrogenase gene from A. fumigatus with the luciferase gene from Photinus pyralis to control the expression of the bioluminescent reporter. A. fumigatus transformed with this construct revealed high bioluminescence under all tested growth conditions. Furthermore, light emission correlated with the number of conidia used for inoculation and with the biomass formed after different incubation times. The bioluminescent strains were suitable to study the effectiveness of antifungals in vitro by several independent methods, including the determination of light emission with a microplate reader and the direct visualization of light emission with an IVIS 100 system. Moreover, when glucocorticoid-treated immunosuppressed mice were infected with a bioluminescent strain, light emission was detected from infected lungs, allowing the visualization of the progression of invasive aspergillosis. Therefore, this new bioluminescence tool is suitable to study the in vitro effectiveness of drugs and the disease development, localization, and burden of fungi within tissues and may also provide a powerful tool to study the effectiveness of antifungals in vivo.
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Ruiz-Cendoya M, Marine M, Guarro J. Combined therapy in treatment of murine infection by Fusarium solani. J Antimicrob Chemother 2008; 62:543-6. [DOI: 10.1093/jac/dkn215] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Stress, drugs, and evolution: the role of cellular signaling in fungal drug resistance. EUKARYOTIC CELL 2008; 7:747-64. [PMID: 18375617 DOI: 10.1128/ec.00041-08] [Citation(s) in RCA: 203] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Alcazar-Fuoli L, Rodríguez-Tudela JL, Mellado E. Antifungal drug resistance in molds: Clinical and microbiological factors. CURRENT FUNGAL INFECTION REPORTS 2008. [DOI: 10.1007/s12281-008-0006-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Aspergillus calidoustus sp. nov., causative agent of human infections previously assigned to Aspergillus ustus. EUKARYOTIC CELL 2008; 7:630-8. [PMID: 18281596 DOI: 10.1128/ec.00425-07] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Aspergillus ustus is a relatively rare human pathogen causing invasive infections in immunocompromised hosts. In this study isolates originating from clinical and other sources have been examined using molecular, morphological, and physiological approaches to clarify their species assignment. Phylogenetic analysis of partial beta-tubulin, calmodulin, actin, and intergenic transcribed spacer sequences indicated that none of the clinical isolates recognized previously as A. ustus belongs to this species. All but two of these isolates formed a well-defined clade related to A. pseudodeflectus based on sequence analysis of protein-coding regions. Morphological and physiological examination of these isolates indicated that they are able to grow above 37 degrees C, in contrast with A. ustus isolates, and give a positive Ehrlich reaction, in contrast with related species including A. granulosus, A. ustus, and A. pseudodeflectus. These isolates are proposed as a new species, A. calidoustus. Antifungal susceptibility testing showed that this species has decreased susceptibilities to several antifungal drugs. The triazoles are inactive in vitro, including the new azole posaconazole.
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Abstract
Scedosporium spp. are increasingly recognized as causes of resistant life-threatening infections in immunocompromised patients. Scedosporium spp. also cause a wide spectrum of conditions, including mycetoma, saprobic involvement and colonization of the airways, sinopulmonary infections, extrapulmonary localized infections, and disseminated infections. Invasive scedosporium infections are also associated with central nervous infection following near-drowning accidents. The most common sites of infection are the lungs, sinuses, bones, joints, eyes, and brain. Scedosporium apiospermum and Scedosporium prolificans are the two principal medically important species of this genus. Pseudallescheria boydii, the teleomorph of S. apiospermum, is recognized by the presence of cleistothecia. Recent advances in molecular taxonomy have advanced the understanding of the genus Scedosporium and have demonstrated a wider range of species than heretofore recognized. Studies of the pathogenesis of and immune response to Scedosporium spp. underscore the importance of innate host defenses in protection against these organisms. Microbiological diagnosis of Scedosporium spp. currently depends upon culture and morphological characterization. Molecular tools for clinical microbiological detection of Scedosporium spp. are currently investigational. Infections caused by S. apiospermum and P. boydii in patients and animals may respond to antifungal triazoles. By comparison, infections caused by S. prolificans seldom respond to medical therapy alone. Surgery and reversal of immunosuppression may be the only effective therapeutic options for infections caused by S. prolificans.
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Ledbetter EC, Patten VH, Scarlett JM, Vermeylen FM. In vitro susceptibility patterns of fungi associated with keratomycosis in horses of the northeastern United States: 68 cases (1987-2006). J Am Vet Med Assoc 2007; 231:1086-91. [PMID: 17916036 DOI: 10.2460/javma.231.7.1086] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine in vitro susceptibility patterns of fungi associated with keratomycosis in horses in the northeastern United States and compare those patterns with results of studies from other geographic regions. DESIGN Retrospective case series. ANIMALS 68 horses with keratomycosis. PROCEDURES Medical records of horses with a clinical diagnosis of keratomycosis, positive results of corneal fungal cultures, and susceptibility data were reviewed from the years 1987 to 2006. Fungal identification and in vitro antifungal susceptibility test results were recorded. The percentage of susceptible isolates was compared among antifungals for all isolates together and for the most common genera individually. RESULTS 74 fungal isolates from 68 horses that met inclusion criteria were identified. Aspergillus, Candida, and Fusarium spp were the most frequent isolates. Grouped isolates had the highest percentage of susceptibility to nystatin (87.7%), natamycin (87.5%), and clotrimazole (80.6%). Grouped isolates had the lowest percentage of susceptibility to fluconazole (15.8%) and miconazole (27.5%). Aspergillus spp (> or = 81.0%) were most susceptible to nystatin, clotrimazole, itraconazole, and natamycin. Candida spp (100%) were most susceptible to ketaconazole, natamycin, and nystatin. Fusarium spp (100%) were only consistently susceptible to natamycin. CONCLUSIONS AND CLINICAL RELEVANCE On the basis of in vitro susceptibility testing, nystatin, natamycin, or clotrimazole is recommended for initial topical treatment of keratomycosis in horses from the northeastern United States. Contrary to results of studies of ocular fungal isolates of horses from other regions, Candida spp were identified more frequently and miconazole had lower in vitro efficacy in the present study.
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Affiliation(s)
- Eric C Ledbetter
- Department of Clinical Sciences, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA
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Abstract
Invasive fungal infections are an important cause of morbidity and mortality in specific patient populations. There has been an impressive increase in the antifungal armamentarium, yet optimal therapies for many invasive fungal infections remain unknown. Genomic sequencing of a number of pathogenic fungi will pave the way to discovering additional newer targets for antifungal drug design. These new discoveries, plus the existing repertoire of antifungal agents, create the need to effectively model single and combination antifungal agents. Future therapies may also include the use of cell-stress pathway inhibitors in combination with existing antifungal agents. This review focuses on combination antifungal therapy against Cryptococcus neoformans, Candida and Aspergillus species. Combination therapy is only supported by randomized clinical trials for cryptococcal meningitis. We review data from in vitro and animal model studies as well as insights from clinical trials to discuss current thoughts and highlight the gaps in our knowledge surrounding combination antifungal therapy.
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Affiliation(s)
- Brahm H Segal
- Roswell Park Cancer Institute, Division of Infectious Diseases, Elm & Carlton Streets, Buffalo, NY 14263, USA.
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Herbrecht R, Flückiger U, Gachot B, Ribaud P, Thiebaut A, Cordonnier C. Treatment of invasive Candida and invasive Aspergillus infections in adult haematological patients. EJC Suppl 2007. [DOI: 10.1016/j.ejcsup.2007.06.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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Meletiadis J, Antachopoulos C, Stergiopoulou T, Pournaras S, Roilides E, Walsh TJ. Differential fungicidal activities of amphotericin B and voriconazole against Aspergillus species determined by microbroth methodology. Antimicrob Agents Chemother 2007; 51:3329-37. [PMID: 17576838 PMCID: PMC2043246 DOI: 10.1128/aac.00345-07] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Antifungal agents may differ in their fungicidal activities against Aspergillus spp. In order to compare the fungicidal activities of voriconazole and amphotericin B against 40 isolates of Aspergillus fumigatus, A. flavus, and A. terreus, we developed a new microbroth colorimetric method for assessing fungicidal activities and determining minimal fungicidal concentrations (MFCs). This methodology follows the antifungal susceptibility testing reference method M-38A for MIC determination. After drug removal and addition of fresh medium, growth of viable conidia adhering to the bottoms of the microtitration wells was assessed by a colorimetric assay of metabolic activity after 24 h of incubation. The new method was faster (six times), reproducible (92 to 97%), and in agreement with culture-based MFCs (91 to 100%). Differential fungicidal activities of voriconazole and amphotericin B were found among the three Aspergillus species, with A. fumigatus and A. flavus having the lowest (1 and 2 mg/liter, respectively) and A. terreus the highest (>16 mg/liter) median amphotericin B MFCs; A. flavus had a lower median voriconazole MFC (4 mg/liter) than the other species (>8 mg/liter; P < 0.05). Amphotericin B was fungicidal (MFC/MIC </= 4) against all A. fumigatus and A. flavus isolates but no A. terreus isolates, whereas voriconazole was fungicidal against 82% of A. flavus isolates and fungistatic (MFC/MIC > 4) against 94% of A. fumigatus and 84% of A. terreus isolates. The new methodology revealed a concentration-dependent sigmoid pattern of fungicidal effects, indicating that fungicidal activity is not an all-or-nothing phenomenon and that some degree of fungicidal action can be found even for agents considered fungistatic based on the MFC/MIC ratio.
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Affiliation(s)
- Joseph Meletiadis
- Pediatric Oncology Branch, National Cancer Institute, Bethesda, MD 20892, USA
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Ito SI, Ihara T, Tamura H, Tanaka S, Ikeda T, Kajihara H, Dissanayake C, Abdel-Motaal FF, El-Sayed MA. alpha-Tomatine, the major saponin in tomato, induces programmed cell death mediated by reactive oxygen species in the fungal pathogen Fusarium oxysporum. FEBS Lett 2007; 581:3217-22. [PMID: 17585910 DOI: 10.1016/j.febslet.2007.06.010] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2007] [Revised: 05/21/2007] [Accepted: 06/08/2007] [Indexed: 10/23/2022]
Abstract
The tomato saponin alpha-tomatine has been proposed to kill sensitive cells by binding to cell membranes followed by leakage of cell components. However, details of the modes of action of the compound on fungal cells are poorly understood. In the present study, mechanisms involved in alpha-tomatine-induced cell death of fungi were examined using a filamentous pathogenic fungus Fusarium oxysporum. alpha-Tomatine-induced cell death of F. oxysporum (TICDF) occurred only under aerobic conditions and was blocked by the mitochondrial F(0)F(1)-ATPase inhibitor oligomycin, the caspase inhibitor D-VAD-fmk, and protein synthesis inhibitor cycloheximide. Fungal cells exposed to alpha-tomatine showed TUNEL-positive nuclei, depolarization of transmembrane potential of mitochondria, and reactive oxygen species (ROS) accumulation. These results suggest that TICDF occurs through a programmed cell death process in which mitochondria play a pivotal role. Pharmacological studies using inhibitors suggest that alpha-tomatine activates phosphotyrosine kinase and monomeric G-protein signaling pathways leading to Ca(2+) elevation and ROS burst in F. oxysporum cells.
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Affiliation(s)
- Shin-Ichi Ito
- Department of Biological and Environmental Sciences, Faculty of Agriculture, Yamaguchi University, Yamaguchi, Yamaguchi, Japan.
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