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de Oliveira AA, Carmo Silva LD, Neves BJ, Fiaia Costa VA, Muratov EN, Andrade CH, de Almeida Soares CM, Alves VM, Pereira M. Cheminformatics-driven discovery of hit compounds against Paracoccidioides spp. Future Med Chem 2023; 15:1553-1567. [PMID: 37727967 DOI: 10.4155/fmc-2022-0288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/21/2023] Open
Abstract
Aims: The development of safe and effective therapies for treating paracoccidioidomycosis using computational strategies were employed to discover anti-Paracoccidioides compounds. Materials & methods: We 1) collected, curated and integrated the largest library of compounds tested against Paracoccidioides spp.; 2) employed a similarity search to virtually screen the ChemBridge database and select nine compounds for experimental evaluation; 3) performed an experimental evaluation to determine the minimum inhibitory concentration and minimum fungicidal concentration as well as cytotoxicity; and 4) employed computational tools to identify potential targets for the most active compounds. Seven compounds presented activity against Paracoccidioides spp. Conclusion: These compounds are new hits with a predicted mechanisms of action, making them potentially attractive to develop new compounds.
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Affiliation(s)
- Amanda Alves de Oliveira
- Institute of Tropical Pathology & Public Health, Federal University of Goiás, Goiânia, 74690-900, Brazil
- Laboratory for Molecular Biology, Institute of Biological Sciences, Federal University of Goiás, 74690-900, Brazil
| | - Lívia do Carmo Silva
- Laboratory for Molecular Biology, Institute of Biological Sciences, Federal University of Goiás, 74690-900, Brazil
| | - Bruno Junior Neves
- Laboratory of Cheminformatics, Faculty of Pharmacy, Federal University of Goiás, 74690-900, Brazil
| | | | - Eugene N Muratov
- Laboratory for Molecular Modeling, Division of Chemical Biology & Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, NC 27599, USA
- Department of Pharmaceutical Sciences, Federal University of Paraiba, Joao Pessoa, 58051-900, Brazil
| | - Carolina Horta Andrade
- Laboratory for Molecular Modeling & Design, Faculty of Pharmacy, Federal University of Goiás, 74690-900, Brazil
| | | | - Vinicius M Alves
- Laboratory for Molecular Modeling, Division of Chemical Biology & Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, NC 27599, USA
- Laboratory for Molecular Modeling & Design, Faculty of Pharmacy, Federal University of Goiás, 74690-900, Brazil
| | - Maristela Pereira
- Laboratory for Molecular Biology, Institute of Biological Sciences, Federal University of Goiás, 74690-900, Brazil
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Cárdenas-Laverde D, Barbosa-Cornelio R, Coy-Barrera E. Antifungal Activity against Fusarium oxysporum of Botanical End-Products: An Integration of Chemical Composition and Antifungal Activity Datasets to Identify Antifungal Bioactives. PLANTS (BASEL, SWITZERLAND) 2021; 10:plants10122563. [PMID: 34961034 PMCID: PMC8705217 DOI: 10.3390/plants10122563] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 11/22/2021] [Accepted: 11/22/2021] [Indexed: 05/10/2023]
Abstract
Plants produce various compounds as defensive barriers to naturally control fungal diseases. Among them, vascular wilt caused by Fusarium oxysporum is one of the most destructive diseases in crops, causing relevant economic losses. The application of synthetic fungicides is the most used management for this disease. However, this kind of method also involves adverse environmental impacts. Therefore, alternative methods are continuously being developed as a strategy to be involved in integrated pest management programs. Thus, as part of our research on antifungals of plant origin, a group of botanical extracts was assessed for the respective inhibitory effect on mycelium and conidia of F. oxysporum. Mycelial growth inhibition was measured in 12-well plates containing amended semi-solid medium, whereas conidial susceptibility was determined through microdilution. The identification of the bioactive compounds among test extracts was performed using an indirect approach, consisting of the integration of chemical composition and antifungal activity datasets through single-Y orthogonal partial least squares (OPLS) regression. Results showed that Piper aduncum extract was the most potent mycelial growth inhibitor whereas P. elongatum exhibited the best effect on conidia susceptibility. The active compounds identified through statistical integration and subsequent isolation were piperaduncin C, asebogenin and (-)-methyllinderatin. These findings indicated that the integrative, indirect approach is useful for the identification of bioactive metabolites from botanical extracts to be further used as biological protective agents against this phytopathogen.
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Lima PG, Freitas CDT, Oliveira JTA, Neto NAS, Amaral JL, Silva AFB, Sousa JS, Franco OL, Souza PFN. Synthetic antimicrobial peptides control Penicillium digitatum infection in orange fruits. Food Res Int 2021; 147:110582. [PMID: 34399551 DOI: 10.1016/j.foodres.2021.110582] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 05/07/2021] [Accepted: 06/29/2021] [Indexed: 11/17/2022]
Abstract
Fungal contamination is among the main reasons for food spoilage, affecting food safety and the economy. Among fungi, Penicillium digitatum is a major agent of this problem. Here, the in vitro activity of eight synthetic antimicrobial peptides was assessed against P. digitatum, and their action mechanisms were evaluated. All peptides were able to inhibit fungal growth. Furthermore, atomic force and fluorescence microscopies revealed that all peptides targeted the fungal membrane leading to pore formation, loss of internal content, and death. The induction of high levels of reactive oxygen species (ROS) was also a mechanism employed by some peptides. Interestingly, only three peptides (PepGAT, PepKAA, and Mo-CBP3-PepI) effectively control P. digitatum colonization in orange fruits, at a concentration (50 µg mL-1) 20-fold lower than the commercial food preservative (sodium propionate). Altogether, PepGAT, PepKAA, and Mo-CBP3-PepI showed high biotechnological potential as new food preservatives to control food infection by P. digitatum.
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Affiliation(s)
- Patrícia G Lima
- Department of Biochemistry and Molecular Biology, Federal University of Ceará, Fortaleza, Ceará CEP 60.440-554, Brazil
| | - Cleverson D T Freitas
- Department of Biochemistry and Molecular Biology, Federal University of Ceará, Fortaleza, Ceará CEP 60.440-554, Brazil
| | - Jose T A Oliveira
- Department of Biochemistry and Molecular Biology, Federal University of Ceará, Fortaleza, Ceará CEP 60.440-554, Brazil
| | - Nilton A S Neto
- Department of Biochemistry and Molecular Biology, Federal University of Ceará, Fortaleza, Ceará CEP 60.440-554, Brazil
| | - Jackson L Amaral
- Department of Biochemistry and Molecular Biology, Federal University of Ceará, Fortaleza, Ceará CEP 60.440-554, Brazil; Department of Physics, Federal University of Ceará, Fortaleza, Brazil
| | - Ayrles F B Silva
- Department of Biochemistry and Molecular Biology, Federal University of Ceará, Fortaleza, Ceará CEP 60.440-554, Brazil; Department of Physics, Federal University of Ceará, Fortaleza, Brazil
| | - Jeanlex S Sousa
- Department of Physics, Federal University of Ceará, Fortaleza, Brazil
| | - Octávio L Franco
- S-Inova Biotech, Programa de Pós Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande 79117900, Brazil; Centro de Análises Proteômicas e Bioquímicas, Universidade Católica de Brasília, Brasília 70790160, Brazil
| | - Pedro F N Souza
- Department of Biochemistry and Molecular Biology, Federal University of Ceará, Fortaleza, Ceará CEP 60.440-554, Brazil.
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In Vitro Evaluation of Radiolabeled Amphotericin B for Molecular Imaging of Mold Infections. Antimicrob Agents Chemother 2020; 64:AAC.02377-19. [PMID: 32393491 DOI: 10.1128/aac.02377-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 05/02/2020] [Indexed: 12/17/2022] Open
Abstract
Invasive pulmonary aspergillosis and mucormycosis are life-threatening complications in immunocompromised patients. A rapid diagnosis followed by early antifungal treatment is essential for patient survival. Given the limited spectrum of biomarkers for invasive mold infections, recent studies have proposed the use of radiolabeled siderophores or antibodies as molecular probes to increase the specificity of radiological findings by nuclear imaging modalities. While holding enormous diagnostic potential, most of the currently available molecular probes are tailored to the detection of Aspergillus species, and their cost-intensive and sophisticated implementation restricts their accessibility at less specialized centers. In order to develop cost-efficient and broadly applicable tracers for pulmonary mold infections, this study established streamlined and high-yielding protocols to radiolabel amphotericin B (AMB) with the gamma emitter technetium-99m (99mTc-AMB) and the positron emitter gallium-68 (68Ga-AMB). The radiochemical purity of the resulting tracers consistently exceeded 99%, and both probes displayed excellent stability in human serum (>98% after 60 to 240 min at 37°C). The uptake kinetics by representative mold pathogens were assessed in an in vitro Transwell assay using infected endothelial cell layers. Both tracers accumulated intensively and specifically in Transwell inserts infected with Aspergillus fumigatus, Rhizopus arrhizus, and other clinically relevant mold pathogens compared with their accumulation in uninfected inserts and inserts infected with bacterial controls. Inoculum-dependent enrichment was confirmed by gamma counting and autoradiographic imaging. Taken together, this pilot in vitro study proposes 99mTc-AMB and 68Ga-AMB to be facile, stable, and specific probes, meriting further preclinical in vivo evaluation of radiolabeled amphotericin B for molecular imaging in invasive mycoses.
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Effect of the Novel Antifungal Drug F901318 (Olorofim) on Growth and Viability of Aspergillus fumigatus. Antimicrob Agents Chemother 2018; 62:AAC.00231-18. [PMID: 29891595 DOI: 10.1128/aac.00231-18] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 06/02/2018] [Indexed: 11/20/2022] Open
Abstract
F901318 (olorofim) is a novel antifungal drug that is highly active against Aspergillus species. Belonging to a new class of antifungals called the orotomides, F901318 targets dihydroorotate dehydrogenase (DHODH) in the de novo pyrimidine biosynthesis pathway. In this study, the antifungal effects of F901318 against Aspergillus fumigatus were investigated. Live cell imaging revealed that, at a concentration of 0.1 μg/ml, F901318 completely inhibited germination, but conidia continued to expand by isotropic growth for >120 h. When this low F901318 concentration was applied to germlings or vegetative hyphae, their elongation was completely inhibited within 10 h. Staining with the fluorescent viability dye bis-(1,3-dibutylbarbituric acid) trimethine oxonol (DiBAC) showed that prolonged exposure to F901318 (>24 h) led to vegetative hyphal swelling and a decrease in hyphal viability through cell lysis. The time-dependent killing of F901318 was further confirmed by measuring the fungal biomass and growth rate in liquid culture. The ability of hyphal growth to recover in drug-free medium after 24 h of exposure to F901318 was strongly impaired compared to that of the untreated control. A longer treatment of 48 h further improved the antifungal effect of F901318. Together, the results of this study indicate that F901318 initially has a fungistatic effect on Aspergillus isolates by inhibiting germination and growth, but prolonged exposure is fungicidal through hyphal swelling followed by cell lysis.
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Brancini GTP, Tonani L, Rangel DEN, Roberts DW, Braga GUL. Species of the Metarhizium anisopliae complex with diverse ecological niches display different susceptibilities to antifungal agents. Fungal Biol 2017; 122:563-569. [PMID: 29801801 DOI: 10.1016/j.funbio.2017.12.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 12/04/2017] [Accepted: 12/06/2017] [Indexed: 01/07/2023]
Abstract
Species of the Metarhizium anisopliae complex are globally ubiquitous soil-inhabiting and predominantly insect-pathogenic fungi. The Metarhizium genus contains species ranging from specialists, such as Metarhizium acridum that only infects acridids, to generalists, such as M. anisopliae, Metarhizium brunneum, and Metarhizium robertsii that infect a broad range of insects and can also colonize plant roots. There is little information available about the susceptibility of Metarhizium species to clinical and non-clinical antifungal agents. We determined the susceptibility of 16 isolates comprising four Metarhizium species with different ecological niches to seven clinical (amphotericin B, ciclopirox olamine, fluconazole, griseofulvin, itraconazole, tebinafine, and voriconazole) and one non-clinical (benomyl) antifungal agents. All isolates of the specialist M. acridum were clearly more susceptible to most antifungals than the isolates of the generalists M. anisopliae sensu lato, M. brunneum, and M. robertsii. All isolates of M. anisopliae, M. brunneum, and M. robertsii were resistant to fluconazole and some were also resistant to amphotericin B. The marked differences in susceptibility between the specialist M. acridum and the generalist Metarhizium species suggest that this characteristic is associated with their different ecological niches, and may assist in devising rational antifungal treatments for the rare cases of mycoses caused by Metarhizium species.
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Affiliation(s)
- Guilherme T P Brancini
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP 14040-903, Brazil
| | - Ludmilla Tonani
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP 14040-903, Brazil
| | - Drauzio E N Rangel
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, GO 74605-050, Brazil
| | - Donald W Roberts
- Department of Biology, Utah State University, Logan, UT 84322-5305, USA
| | - Gilberto U L Braga
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP 14040-903, Brazil.
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Yamaguchi H. Potential of Ravuconazole and its Prodrugs as the New OralTherapeutics for Onychomycosis. Med Mycol J 2017; 57:E93-E110. [PMID: 27904057 DOI: 10.3314/mmj.16-00006] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Onychomycosis is a fungal infection of the nail apparatus caused by dermatophytes, Candida and non-dermatophytic molds. It is highly prevalent in the general population worldwide and also responsible for significant morbidity and complications and does not usually cure itself. Thus, the condition needs to be treated in view of physical and psychological problems produced. Currently, oral medications using terbinafine are the most effective therapy, but it has relatively limited therapeutic success, particularly for long-term management. Such existing oral therapies are associated with high recurrence rates and treatment failure, as well as with potential adverse events and drug-drug interactions. In the light of these issues, development of more efficacious and safer alternatives for the treatment of onychomycosis is warranted.Ravuconazole and its prodrugs are promising new drug candidates for oral therapy of onychomycosis, among which a water-soluble prodrug, mono-lysine phosphoester derivative (E1224 or BFE1224) is in the most advanced stage of clinical development; a Phase II dose-finding study has been successfully completed and Phase III comparative studies are in progress in Japan.This review aims to summarize our current status of knowledge and information on ravuconazole and its prodrugs, particularly BFE1224, as the potential oral treatment option for onychomycosis. It also summarize the clinical features of onychomycosis with particular stress on its etiology, epidemiology, and current therapeutic options and their limitations. Given its clinical usefulness, BFE1224 may become a valuable addition to the current armamentarium for the treatment of onychomycosis.
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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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Abstract
Aspergillus terreus can cause invasive infections in humans, which are often refractory to therapy with the antifungal drug amphotericin B and have a propensity to dissemination. The organism has diverse colony morphology, and sub-typing studies have demonstrated that isolates of A. terreus are diverse in their genotypes. However, detailed phylogenetic studies of section Terrei employing sequence information from protein coding regions have not been thus far attempted. Interestingly, A. terreus produces unicellular forms called accessory conidia in vitro and during infection; the clinical relevance of these structures are not well understood. This paper presents an overview of the morphology, species identification strategies, and molecular epidemiology of A. terreus.
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Affiliation(s)
- S Arunmozhi Balajee
- Mycotic Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
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Abstract
BACKGROUND Historically clinicians have preferred to use 'cidal' antifungal agents, particularly in critically ill patients. However, data to support the belief that the preferential use of a 'cidal' agent results in better patient outcomes has been lacking. OBJECTIVE This review examined the in vitro definitions of fungicidal and fungistatic as well as their strengths and limitations. METHODS A Medline search was performed in order to identify literature that examined the in vitro or in vivo impact of fungicidal and fungistatic activity. The study examined three common invasive fungal infections, namely cryptococcal meningitis, candidemia and invasive aspergillosis, where sufficient comparisons of fungicidal and fungistatic agents have been performed to allow for the evaluation of the clinical importance of these in vitro findings. RESULTS AND CONCLUSION A clear clinical benefit of fungicidal agents over those with fungistatic activity remains elusive. Patients with cryptococcal meningitis clearly benefit from early fungicidal therapy but require long-term suppression. The data in invasive Candida sp. infections are tantalizing and suggest that fungicidal therapy may be important. However, the data for invasive aspergillosis do not support the hypothesis that fungicidal activity improves outcomes.
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Affiliation(s)
- James S Lewis
- University Health System, Department of Pharmacy, 4502 Medical Drive, San Antonio, TX 78229, USA.
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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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Carrillo-Muñoz AJ, Quindós G, Ruesga M, del Valle O, Pemán J, Cantón E, Hernández-Molina JM, Santos P. In vitro antifungal susceptibility testing of filamentous fungi with Sensititre Yeast OneTM. Mycoses 2006; 49:293-7. [PMID: 16784443 DOI: 10.1111/j.1439-0507.2006.01250.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Sensititre is a colorimetric microdilution method for in vitro antifungal susceptibility testing based on the M27-A document (National Committee for Clinical Laboratory Standards) for yeasts. Difference between both methods is the presence of Alamar-blue and RPMI 1640 (glucose 2%) as culture medium. Antifungal susceptibility to amphotericin B, fluconazole, itraconazole, ketoconazole and flucytosine, 100 opportunistic filamentous fungi (Aspergillus spp., Fusarium spp., Scedosporium spp.) obtained from pathological samples was determined by the Sensititre method. Induction to conidium and sporangiospore formation at 35 degrees C was used to get inoculum and plates were covered by 1 ml of saline and suspensions were made by gently probing by a sterile loop. Optical densities of the conidial suspensions were adjusted to 80-82% transmittance for Aspergillus spp. and 68-70% for the rest of strains tested. Final inoculum concentration size was 0.4 x 10(4)-5 x 10(4) CFU ml(-1). Readings were made at 72 h of incubation at 35 degrees C; amphotericin B and itraconazole was active against Aspergillus fumigatus with CMI90 1 and 0.5 microg ml(-1), respectively, opposite to Scedosporium prolificans and Scedosporium apiospermum. As it was expected, a CMI90 of 256 microg ml(-1) for fluconazole and CMI90 for flucytosine amounting to 64 g ml(-1) were obtained. Sensititre Yeast One is a useful method and an alternative to reference methods to determine antifungal susceptibility of filamentous fungi for clinical laboratory routine. Correlation with microdilution results is studied. New triazole derivatives should be included as soon as their clinical use will be feasible.
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Wetter TJ, Hazen KC, Cutler JE. Comparison between Aspergillus fumigatus conidia and hyphae susceptibilities to amphotericin B, itraconazole, and voriconazole by use of the mold rapid susceptibility assay. Med Mycol 2006; 43:525-32. [PMID: 16323310 DOI: 10.1080/13693780500050796] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Although hyphae are the morphological form observed in tissue during invasive Aspergillus fumigatus infections, antifungal susceptibility testing for A. fumigatus utilizes conidial inocula. Previous studies have yielded conflicting results as to whether conidia adequately reflect antifungal susceptibility of hyphae, but the ease of handling and quantification of conidia have prompted their use in such assays. The mold rapid susceptibility assay, which utilizes a conidial inoculum (cRSA), was adapted as a novel method to assess the utility of conidial versus hyphal inocula (hRSA) to further evaluate the susceptibility of A. fumigatus conidia and hyphae to amphotericin B (AMB), itraconazole (ITC), and voriconazole (VRC). Conidial inocula were prepared as previously described for the cRSA and minimum inhibitory values (MIC) were determined. For the hRSA, microtiter test wells lacking antifungal drug were inoculated with a standardized conidial inoculum and incubated for 12 h at 35-37 degrees C to allow formation of hyphae. Following addition of antifungal drug and 48 h incubation at 35-37 degrees C, hRSA antifungal minimum inhibitory concentration (MIC) values were determined by analysing the pattern of residual glucose levels in hRSA test wells. hRSA MIC values of each strain were influenced by hyphal inoculum size, with increasing hyphal inoculum size corresponding to increased AMB, ITC and VRC MIC values. Comparisons between the hRSA and cRSA MIC values demonstrated insignificant differences in conidial and hyphal susceptibility to drug, thus justifying the use of either fungal form in RSA-based susceptibility testing of A. fumigatus isolates. The RSA may be adapted for use of similar testing of other invasive molds that predominate as hyphal forms in tissue.
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Affiliation(s)
- Tracy J Wetter
- Department of Microbiology, Montana State University, Bozeman, USA
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Rubio MC, de Ocáriz IR, Gil J, Benito R, Rezusta A. Potential fungicidal effect of voriconazole against Candida spp. Int J Antimicrob Agents 2005; 25:264-7. [PMID: 15737524 DOI: 10.1016/j.ijantimicag.2004.11.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2004] [Accepted: 11/01/2004] [Indexed: 11/17/2022]
Abstract
In vitro fungistatic and fungicidal activities of voriconazole were evaluated against 114 isolates of Candida spp. MICs were determined using the NCCLS M27-A2 broth microdilution method. Minimum fungicidal concentrations (MFCs) were defined as the lowest drug concentrations that yielded < or = 5 colonies (> or = 98% killing activity). The fungicidal activity could be only evaluated against 45.6% of the isolates (52 of 114 isolates) because trailing growth occurred, and 30 of these 52 isolates (57.69%) showed MFC values < or = 1 mg/l. There was little or no fungicidal activity against C. albicans and C. tropicalis. In contrast, all C. krusei were killed by 1-2 mg/l voriconazole. In conclusion, our data show that the fungicidal effect of voriconazole against Candida spp. is species dependent.
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Affiliation(s)
- M Carmen Rubio
- Microbiology, Hospital Clínico Universitario Lozano Blesa, Domingo Miral s/n, Zaragoza 50009, Spain.
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Gomez-Lopez A, Aberkane A, Petrikkou E, Mellado E, Rodriguez-Tudela JL, Cuenca-Estrella M. Analysis of the influence of Tween concentration, inoculum size, assay medium, and reading time on susceptibility testing of Aspergillus spp. J Clin Microbiol 2005; 43:1251-5. [PMID: 15750092 PMCID: PMC1081276 DOI: 10.1128/jcm.43.3.1251-1255.2005] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The influence of several test variables on susceptibility testing of Aspergillus spp. was assessed. A collection of 28 clinical isolates was tested against amphotericin B, itraconazole, voriconazole, and terbinafine. Inoculum size (10(4) CFU/ml versus 10(5) CFU/ml) and glucose supplementation (0.2% versus 2%) did not have significant effects on antifungal susceptibility testing results and higher inoculum size and glucose concentration did not falsely elevate MICs. In addition, antifungal susceptibility testing procedure with an inoculum size of 10(5) CFU/ml distinctly differentiated amphotericin B or itraconazole-resistant Aspergillus strains in vivo from the susceptible ones. Time of incubation significantly affected the final values of MICs, showing major increases (two to six twofold dilutions, P < 0.01 by analysis of variance) between MIC readings at 24 and 48 h, but no differences were observed between antifungal susceptibility testing results obtained at 48 h and at 72 h. Significantly higher MICs were uniformly associated with higher concentrations of Tween (P < 0.01), used as a dispersing agent in the preparation of inoculum suspensions. The geometric mean MICs showed increases of between 1.5- and 10-fold when the Tween concentration varied from 0.1% (the geometric means for amphotericin B, itraconazole, voriconazole, and terbinafine were 1.29, 0.69, 1.06, and 0.64 mug/ml, respectively) to 5% (the geometric means for amphotericin B, itraconazole, voriconazole, and terbinafine were 1.97, 5.79, 1.60, and 4.66 mug/ml, respectively). The inhibitory effect of Tween was clearly increased with inoculum sizes of 10(5) CFU/ml and was particularly dramatic for itraconazole, terbinafine, and Aspergillus terreus. The inoculum effect was not observed when the Tween concentration was below 0.5% (P > 0.01).
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Affiliation(s)
- Alicia Gomez-Lopez
- Servicio de Micología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Ctra Majadahonda-Pozuelo, Km 2. 28220 Majadahonda, Madrid, Spain
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16
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Krishnan S, Manavathu EK, Chandrasekar PH. A comparative study of fungicidal activities of voriconazole and amphotericin B against hyphae of Aspergillus fumigatus. J Antimicrob Chemother 2005; 55:914-20. [PMID: 15824093 DOI: 10.1093/jac/dki100] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES To study the in vitro fungicidal activity of voriconazole against hyphae of Aspergillus fumigatus and compare the results with those obtained for the known fungicidal drug amphotericin B. METHODS A. fumigatus mycelia were grown on Sabouraud dextrose agar and in peptone yeast extract glucose broth until the cultures reached a mid-logarithmic growth phase. The fungicidal activities of voriconazole and amphotericin B against actively growing hyphae of A. fumigatus were examined by a kill-curve experiment and a fungal cell viability test. For the kill-curve study, the drug-treated hyphae were washed, homogenized and resuspended in 1 mL of sterile water, diluted 10-1000 fold and aliquots of 0.1 mL were spread on Sabouraud dextrose agar and allowed to grow for 48 h at 35 degrees C. The cfu were determined and plotted against drug concentrations for each time of exposure to obtain the kill curve. The viability of drug-treated A. fumigatus hyphae was determined by their ability to reduce tetrazolium compound 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide. RESULTS Exposure of A. fumigatus hyphae to several concentrations (1-16 mg/L) of voriconazole or amphotericin B for various time intervals killed the hyphae in a time- and drug concentration-dependent manner. Voriconazole at 1 mg/L killed >95% of the hyphae grown on Sabouraud dextrose agar after 48 h of exposure, whereas amphotericin B at the same concentration killed approximately 70% of the hyphae after exposure for the same duration. Approximately 99% killing of hyphae grown in peptone yeast extract glucose broth was obtained for voriconazole at 1 mg/L after 48 h of exposure, whereas amphotericin B at 1 mg/L yielded approximately 82% killing after 48 h. The fungal cell viability test by tetrazolium reduction assay showed that mycelia exposed to > or =1 mg/L (Sabouraud dextrose agar blocks) and > or =2 mg/L (broth cultures) of voriconazole for 48 h completely failed to reduce 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide. At low concentrations (1-2 mg/L) amphotericin B had no detectable effect on 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide reduction by drug-treated mycelia, whereas mycelia treated with 16 mg/L for 48 h showed approximately 50% inhibition of 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide reduction compared with the control. CONCLUSIONS Voriconazole possesses excellent fungicidal activity against actively growing hyphae of A. fumigatus. A comparison of results with those obtained for the known fungicidal drug amphotericin B shows that, in peptone yeast extract glucose broth, voriconazole has superior fungicidal activity against A. fumigatus hyphae compared with that of amphotericin B.
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Affiliation(s)
- Suganthini Krishnan
- Division of Infectious Diseases, Department of Internal Medicine, 427 Lande Building, Wayne State University, 550 E. Canfield, Detroit, MI 48201, USA
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Graybill JR, Hernandez S, Bocanegra R, Najvar LK. Antifungal therapy of murine Aspergillus terreus infection. Antimicrob Agents Chemother 2004; 48:3715-9. [PMID: 15388425 PMCID: PMC521897 DOI: 10.1128/aac.48.10.3715-3719.2004] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aspergillus terreus is a species which is being seen increasingly frequently and which is highly resistant to amphotericin B in vitro and clinically. We evaluated amphotericin B, caspofungin, and posaconazole in a murine model of acute invasive aspergillosis. Caspofungin and posaconazole both appeared beneficial and may be reasonable treatment alternatives for infection with A. terreus.
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Affiliation(s)
- John R Graybill
- The University of Texas Health Science Center at San Antonio, Department of Medicine, Division of Infectious Diseases (mail code 7881), 7703 Floyd Curl Dr., San Antonio, TX 78229-3900, USA
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18
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Araujo R, Rodrigues AG, Pina-Vaz C. A fast, practical and reproducible procedure for the standardization of the cell density of an Aspergillus suspension. J Med Microbiol 2004; 53:783-786. [PMID: 15272066 DOI: 10.1099/jmm.0.05425-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The progressive increase of invasive disease and reports of resistance among Aspergillus species emphasizes the need for reproducible antifungal susceptibility testing. Inoculum standardization is a crucial step in such procedures. The objective of this study was to develop a fast and precise method of evaluating the cell density of an Aspergillus spore suspension, as an alternative to spectrometric readings or cell-counting with a haemocytometer. Densimat (bioMérieux) is a portable photometer that shows a good correlation with spectrometric readings and can advantageously replace the cumbersome, time-consuming method of cell-counting. Thus, Densimat brings significant improvement to the reproducibility and feasibility of standardization of a fungal inoculum.
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Affiliation(s)
- Ricardo Araujo
- Department of Microbiology, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal 2IPATIMUP, University of Porto, Portugal
| | - Acacio G Rodrigues
- Department of Microbiology, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal 2IPATIMUP, University of Porto, Portugal
| | - Cidalia Pina-Vaz
- Department of Microbiology, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal 2IPATIMUP, University of Porto, Portugal
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19
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Fernández-Torres B, Inza I, Guarro J. Comparison of in vitro antifungal susceptibilities of conidia and hyphae of dermatophytes with thick-wall macroconidia. Antimicrob Agents Chemother 2004; 47:3371-2. [PMID: 14506062 PMCID: PMC201167 DOI: 10.1128/aac.47.10.3371-3372.2003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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20
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Abstract
Fungal pathogens are increasingly important causes of respiratory disease, yet the number of antifungal agents available for clinical use is limited. Use of amphotericin B deoxycholate is hampered by severe toxicity. Triazole agents currently available have significant drug interactions; fluconazole has a limited spectrum of activity and itraconazole was, until recently, available only in oral formulations with limited bioavailability. The development of resistance to all three agents is increasingly being recognized and some filamentous fungi are resistant to the action of all of these agents. In the past few years, new antifungal agents and new formulations of existing agents have become available.The use of liposomal amphotericin B preparations is associated with reduced, but still substantial, rates of nephrotoxicity and infusion-related reactions. An intravenous formulation of itraconazole has been introduced, and several new triazole agents have been developed, with the view of identifying agents that have enhanced potency, broader spectra of action and improved pharmacodynamic properties. One of these, voriconazole, has completed large-scale clinical trials. In addition, caspofungin, the first of a new class of agents, the echinocandins, which inhibit cell wall glucan synthesis, was approved for use in the US in 2001 as salvage therapy for invasive aspergillosis. It is hoped that the availability of these agents will have a significant impact on the morbidity and mortality of fungal respiratory infections. However, at the present time, our ability to assess their impact is limited by the problematic nature of conducting trials for antifungal therapy.
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Affiliation(s)
- Marta Feldmesser
- Departments of Medicine and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
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21
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Rodriguez-Tudela JL, Chryssanthou E, Petrikkou E, Mosquera J, Denning DW, Cuenca-Estrella M. Interlaboratory evaluation of hematocytometer method of inoculum preparation for testing antifungal susceptibilities of filamentous fungi. J Clin Microbiol 2004; 41:5236-7. [PMID: 14605171 PMCID: PMC262490 DOI: 10.1128/jcm.41.11.5236-5237.2003] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A three-laboratory study was performed to evaluate conidium counting in a hematocytometer as a technique of inoculum preparation for susceptibility testing of Aspergillus spp. In addition, inocula were quantified by colony counting and optical density determination. The agreement and correlation coefficient between conidium and colony quantifications were 89.2% and 0.73 (P < 0.01). Correlations with optical density determination were not significant.
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Affiliation(s)
- J L Rodriguez-Tudela
- Unidad de Micología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Spain
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22
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Abstract
The past few years have seen the advent of several new antifungal agents, including those of a new class and a new generation of an existing class. Caspofungin, the first available echinocandin, has greatly expanded the antifungal armamentarium by providing a cell wall-active agent with candidacidal activity as well as demonstrated clinical efficacy in the therapy of aspergillosis refractory to available therapy. In addition, in clinical trials, caspofungin had comparable efficacy to amphotericin B for candidaemia and invasive Candida infections. Caspofungin and two more recently introduced echinocandins, micafungin and anidulafungin, are available as intravenous formulations only and characterised by potent anti-candidal activity, as well as few adverse events and drug interactions. Voriconazole, the first available second-generation triazole, available in both intravenous and oral formulations, has added a new and improved therapeutic option for primary therapy of invasive aspergillosis and salvage therapy for yeasts and other moulds. In a randomised trial, voriconazole demonstrated superior efficacy and a survival benefit compared with amphotericin B followed by other licensed antifungal therapy. This and data from a noncomparative study led to voriconazole becoming a new standard of therapy for invasive aspergillosis. Voriconazole has several important safety issues, including visual adverse events, hepatic enzyme elevation and skin reactions, as well as a number of drug interactions. Posaconazole, only available orally and requiring dose administration four times daily, shows encouraging efficacy in difficult to treat infections due to zygomycetes. Ravuconazole, available in both intravenous and oral formulations, has broad-spectrum in vitro potency and in vivo efficacy against a wide range of fungal pathogens. Clinical studies are underway. Despite the advances offered with each of these drugs, the morbidity and mortality associated with invasive fungal infections remains unacceptable, especially for the most at-risk patients. For individuals with severe immunosuppression as a result of chemotherapy, graft-versus-host disease and its therapy, or transplantation, new drugs and strategies are greatly needed.
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Affiliation(s)
- Helen W Boucher
- Division of Geographic Medicine and Infectious Diseases, Tufts-New England Medical Center, Boston, Massachusetts, USA
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23
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Abstract
BACKGROUND Reports of resistance and intolerance to currently available antifungal agents are increasing. Voriconazole is a broad-spectrum azole antifungal agent structurally derived from fluconazole. It is indicated for the treatment of invasive aspergillosis and serious fungal infections caused by Scedosporium apiospermum and Fusarium species in patients who are unable to tolerate or are refractory to other antifungal therapy. OBJECTIVE This article reviews the pharmacologic and pharmacokinetic properties and clinical usefulness of voriconazole. METHODS Relevant information was identified through a search of MEDLINE (1966-December 2002), Iowa Drug Information Service (1966-December 2002), International Pharmaceutical Abstracts (1970-December 2002), and meeting abstracts of the Infectious Diseases Society of America (1996-2002) and the Interscience Conference on Antimicrobial Agents and Chemotherapy (1996-2002) using the terms voriconazole and UK-109,495. RESULTS In head-to-head comparative trials, voriconazole appeared to be as efficacious as amphotericin B for the treatment of invasive aspergillosis and the empiric treatment of fungal infections in patients with febrile neutropenia. In clinical studies, it was as efficacious as fluconazole for the treatment of oropharyngeal and esophageal candidiasis. The results of in vitro susceptibility studies and case reports suggested that voriconazole may be useful against fluconazole- and/or itraconazole-resistant strains of Candida. Although voriconazole may be associated with a lower incidence of serious systemic adverse effects compared with amphotericin B (13.4% vs 24.3% in 1 pivotal clinical study; P = NS), major adverse effects associated with voriconazole include visual abnormalities ( approximately 30%), skin reactions ( approximately 20%), and elevations in hepatic enzymes (< or =20%). Voriconazole is available as oral and intravenous formulations. Pharmacokinetically, it has widespread distribution, including penetration into cerebral tissue. However, as 80% of voriconazole is hepatically eliminated, primarily via the cytochrome P450 (CYP) isozymes CYP2C19, CYP3A4, and CYP2C9, voriconazole has a high potential for drug interactions, and dose reduction is recommended in patients with mild to moderate hepatic dysfunction (Child-Pugh class A or B). Oral voriconazole may be preferred in patients with a creatinine clearance <50 mL/min due to the potential accumulation of the solubilizing excipient in the parenteral formulation of voriconazole. CONCLUSIONS Voriconazole appears to be a useful alternative to conventional antifungal agents in cases of resistance or intolerance to initial therapy. However, dose adjustment is recommended in patients with hepatic dysfunction, as well as in those receiving medications that may interact with voriconazole via hepatic metabolism.
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Affiliation(s)
- LilyAnn Jeu
- Pharmacy Service, Veterans Affairs Medical Center, Bronx, New York 10468, USA
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24
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Seibold M, Tintelnot K. Susceptibility testing of fungi--current status and open questions. PROGRESS IN DRUG RESEARCH. FORTSCHRITTE DER ARZNEIMITTELFORSCHUNG. PROGRES DES RECHERCHES PHARMACEUTIQUES 2003; Spec No:191-241. [PMID: 12675477 DOI: 10.1007/978-3-0348-7974-3_5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
The increase of fungal infections and the improvement of therapeutical options demand reliable antifungal susceptibility testing. In vitro susceptibility testing of fungi--in contrast to bacteria--is not yet established as a routine method. The NCCIS (National Committee for Clinical Laboratory Standards) guidelines for susceptibility testing of yeasts (and proposed for hyphomycetes) are most important for standardization. Meanwhile, essential parts of this test procedure are accepted, but it should still be improved. The concept of using only one test medium for all drugs and test organisms is not realized so far. There are also some test situations that prevent the NCCLS standard from being applied. Based on our experience, this article describes the NCCLS methods and their modifications. It places emphasis on lipophilic drugs showing controversies despite standardization. Furthermore, the prediction of MICs on the clinical outcome is discussed. Since there are some pitfalls in testing antifungals, this should be done in experienced laboratories only. The MIC has to be regarded as only one, but an important, factor in the management of fungal diseases. Host-, drug-, and pathogen-specific data should be considered simultaneously.
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Affiliation(s)
- Michael Seibold
- Robert Koch-Institut, Mykologie, Nordufer 20, 13353 Berlin, Germany
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25
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Abstract
Voriconazole, a broad-spectrum triazole antifungal agent, inhibits the cytochrome P450-dependent enzyme 14-alpha-sterol demethylase, thereby disrupting the fungal membrane and stopping fungal growth. The drug shows excellent in vitro activity against Aspergillus spp., including itraconazole- and amphotericin B-resistant A. fumigatus isolates. At 12 weeks, 52.8% of voriconazole recipients achieved a successful outcome (complete or partial response) versus 31.6% of amphotericin B recipients in a randomised, nonblind trial in 392 patients (aged > or =12 years) with invasive aspergillosis. Patients received intravenous voriconazole (6 mg/kg once every 12 hours on day 1, then 4 mg/kg once every 12 hours for > or =7 days; patients could then be switched to oral voriconazole 200mg once every 12 hours) or intravenous amphotericin B (1 to 1.5 mg/kg/day for > or=14 days). At the investigators' discretion, those who failed to respond to or experienced toxicity with the initial randomised drug could be switched to other licensed antifungal therapy. Voriconazole was generally well tolerated. The most common treatment-related adverse events were transient visual disturbances (approximately 30% of patients) and skin rashes (6%). Voriconazole was generally better tolerated than amphotericin B; voriconazole recipients experienced significantly (p < 0.02 both comparisons) fewer treatment-related adverse events or serious adverse events. The incidence of visual disturbances was significantly (p < 0.001) higher with voriconazole than amphotericin B treatment.
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Abstract
PURPOSE OF REVIEW An increase in refractory invasive fungal infections in the setting of marrow/solid organ transplantation and other immune-compromising clinical entities has provided the impetus for the development of new, more efficacious/less toxic antifungal agents. This review (1) examines currently available laboratory methods for the in-vitro evaluation of these new agents against both yeasts and filamentous fungi; (2) provides a summary of the most attractive investigational agents currently undergoing clinical trials/development; and (3) outlines the major refractory mycoses in contemporary medicine. RECENT FINDINGS Fluconazole-resistant Candida spp., Trichosporon spp., zygomycetous genera, the endemic mycoses, Scedosporium, Aspergillus, and Fusarium spp., and an ever-expanding list of lesser-known hyaline and phaeoid genera inciting invasive fungal infections comprise the bulk of refractory mycoses in the immune-compromised host. In-vitro data generated from reference-based antifungal susceptibility testing methods indicate an increased armamentarium of potentially efficacious agents against most of these mycoses. SUMMARY The newly approved antifungal agents caspofungin and voriconazole, used either as monotherapy or in combination regimens, have a significantly improved spectrum of activity over previously available therapeutic options. Correlation of clinical outcomes with investigational agents demonstrating in-vivo/in-vitro activity will provide critical information needed for the development of clinically significant minimum inhibitory concentration interpretative breakpoints.
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Affiliation(s)
- Deanna A Sutton
- Fungus Testing Laboratory, Department of Pathology, Unversity of Texas Halth Science Center at San Antonio, Texas 78229-3900, USA.
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27
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Carrillo-Muñoz AJ, Ruesga M, Brio S, del Valle O, Rodriguez V, Santos P, Hernández-Molina JM, Cantón E, Pemán J, Guarro J, Quindós G. Comparison of in vitro antifungal activities of amphotericin B lipid complex with itraconazole against 708 clinical yeast isolates and opportunistic moulds determined by National Committee for Clinical Laboratory Standards methods M27-A and M38-P. Chemotherapy 2002; 48:224-31. [PMID: 12476038 DOI: 10.1159/000066764] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We compared the in vitro antifungal activity of amphotericin B lipid complex (ABLC) with that of itraconazole (ITZ) against 535 yeast strains and 173 opportunistic filamentous fungi by using a microdilution method (National Committee for Clinical Laboratory Standards M27-A and M38-P). The overall geometric mean MIC was 0.13 microg/ml and 0.177 microg/ml for ITZ and ABLC, respectively, and the MIC(50) was 0.125 microg/ml for both agents against yeast isolates. ITZ had a similar or slightly superior efficacy compared to ABLC when tested against Candida albicans, Candida parapsilosis, Cryptococcus neoformans, Candida krusei, Candida glabrata and Candida tropicalis. Effectiveness against C. glabrata was lower for ITZ (MIC(90) 2 microg/ml, and for ABLC, 0.5 microg/ml). For Aspergillus fumigatus, activity of ITZ was superior in comparison with ABLC (MIC(90) 1 and 16 microg/ml, respectively); MIC(90) for Aspergillus niger was 4 and 2 microg/ml for ABLC and ITZ, respectively. Scedosporium spp. showed a low susceptibility to both ABLC and ITZ. In conclusion, ABLC and ITZ are useful alternatives for the treatment of severe fungal infections. The selection of an antifungal agent should be made considering the toxicological and pharmacological properties and cost/benefit relationship and be supported by the susceptibility of the isolate.
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Tortorano AM, Dannaoui E, Meletiadis J, Mallie M, Viviani MA, Piens MA, Rigoni AL, Bastide JM, Grillot R. Effect of medium composition on static and cidal activity of amphotericin B, itraconazole, voriconazole, posaconazole and terbinafine against Aspergillus fumigatus: a multicenter study. J Chemother 2002; 14:246-52. [PMID: 12120878 DOI: 10.1179/joc.2002.14.3.246] [Citation(s) in RCA: 6] [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 effect of the medium composition on the fungistatic (MIC) and fungicidal (MLC) activity of amphotericin B, itraconazole, voriconazole, posaconazole and terbinafine against four Aspergillus fumigatus strains has been investigated by four European laboratories. MICs were determined by broth microdilution, using RPMI 1640 and Antibiotic Medium 3 (AM3), three times in three independent determinations by the four laboratories. MLCs were determined for the three independent determinations by the four laboratories, subculturing 100 microl from each well showing no visible growth after 48 hours. Except for a 2-dilution difference observed in three cases, no differences were observed between MICs determined on the two media. In contrast, a 3- to 6-dilution discrepancy between the MLCs was observed for the azoles. Endpoints on RPMI were higher than those on AM3. A 1-2 dilution difference was noted between both the endpoints of amphotericin B and of terbinafine. The highest inter- and intra-laboratory agreements were reached on AM3. The azoles showed a medium-dependent fungicidal activity.
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Affiliation(s)
- A M Tortorano
- Istituto di Igiene e Medicina Preventiva, Università degli Studi-IRCCS Ospedale Maggiore, Milano, Italy.
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Abstract
Voriconazole is a new triazole antifungal agent structurally related to fluconazole, but with improved potency and spectrum of activity. Voriconazole has good in vitro activity against Candida species, Cryptococcus neoformans, Aspergillus spp. and other mould spp. Initial clinical studies and case reports demonstrate efficacy with voriconazole against invasive aspergillosis and infections caused by C. neoformans, Scedosporium apiospermum, Blastomyces dermatitidis, Coccidioides immitis and Histoplasma capsulatum. Voriconazole is available both as oral and iv. preparations and exhibits complex pharmacokinetics. This drug is metabolised by the cytochrome (CYP) P450 enzyme system and therefore, has potential drug interactions. This review evaluates the current literature regarding the safety and efficacy of voriconazole.
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Affiliation(s)
- Holly L Hoffman
- University of Oklahoma Health Sciences Center, College of Pharmacy, 1110 N. Stonewall Avenue, PO BOX 26901, Oklahoma City, OK 73190-5040, USA.
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Rex JH, Pfaller MA, Walsh TJ, Chaturvedi V, Espinel-Ingroff A, Ghannoum MA, Gosey LL, Odds FC, Rinaldi MG, Sheehan DJ, Warnock DW. Antifungal susceptibility testing: practical aspects and current challenges. Clin Microbiol Rev 2001; 14:643-58, table of contents. [PMID: 11585779 PMCID: PMC88997 DOI: 10.1128/cmr.14.4.643-658.2001] [Citation(s) in RCA: 278] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Development of standardized antifungal susceptibility testing methods has been the focus of intensive research for the last 15 years. Reference methods for yeasts (NCCLS M27-A) and molds (M38-P) are now available. The development of these methods provides researchers not only with standardized methods for testing but also with an understanding of the variables that affect interlaboratory reproducibility. With this knowledge, we have now moved into the phase of (i) demonstrating the clinical value (or lack thereof) of standardized methods, (ii) developing modifications to these reference methods that address specific problems, and (iii) developing reliable commercial test kits. Clinically relevant testing is now available for selected fungi and drugs: Candida spp. against fluconazole, itraconazole, flucytosine, and (perhaps) amphotericin B; Cryptococcus neoformans against (perhaps) fluconazole and amphotericin B; and Aspergillus spp. against (perhaps) itraconazole. Expanding the range of useful testing procedures is the current focus of research in this area.
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Affiliation(s)
- J H Rex
- Division of Infectious Diseases, Department of Internal Medicine, Center for the Study of Emerging and Reemerging Pathogens, University of Texas Medical School, Houston, Texas 77030, USA.
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