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Gautier C, Maciel EI, Ene IV. Approaches for identifying and measuring heteroresistance in azole-susceptible Candida isolates. Microbiol Spectr 2024; 12:e0404123. [PMID: 38483474 PMCID: PMC10986555 DOI: 10.1128/spectrum.04041-23] [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: 11/27/2023] [Accepted: 02/23/2024] [Indexed: 04/06/2024] Open
Abstract
Heteroresistance to antifungal agents poses a significant challenge in the treatment of fungal infections. Currently, the absence of established methods for detecting and measuring heteroresistance impedes progress in understanding this phenomenon in fungal pathogens. In response to this gap, we present a comprehensive set of new and optimized methods designed to detect and quantify azole heteroresistance in Candida albicans. Here, we define two primary assays for measuring heteroresistance: population analysis profiling, based on growth on solid medium, and single-cell assays, based on growth in liquid culture. We observe good correlations between the measurements obtained with liquid and solid assays, validating their utility for studying azole heteroresistance. We also highlight that disk diffusion assays could serve as an additional tool for the rapid detection of heteroresistance. These methods collectively provide a versatile toolkit for researchers seeking to assess heteroresistance in C. albicans. They also serve as a critical step forward in the characterization of antifungal heteroresistance, providing a framework for investigating this phenomenon in diverse fungal species and in the context of other antifungal agents. Ultimately, these advancements will enhance our ability to effectively measure antifungal drug responses and combat fungal infections.IMPORTANCEHeteroresistance involves varying antimicrobial susceptibility within a clonal population. This phenomenon allows the survival of rare resistant subpopulations during drug treatment, significantly complicating the effective management of infections. However, the absence of established detection methods hampers progress in understanding this phenomenon in human fungal pathogens. We propose a comprehensive toolkit to address this gap in the yeast Candida albicans, encompassing population analysis profiling, single-cell assays, and disk diffusion assays. By providing robust and correlated measurements through both solid and liquid assays, this work will provide a framework for broader applications across clinically relevant Candida species. These methods will enhance our ability to understand this phenomenon and the failure of antifungal therapy.
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Affiliation(s)
- Cécile Gautier
- Fungal Heterogeneity Group, Institut Pasteur, Université Paris Cité, Paris, France
| | - Eli I. Maciel
- Fungal Heterogeneity Group, Institut Pasteur, Université Paris Cité, Paris, France
| | - Iuliana V. Ene
- Fungal Heterogeneity Group, Institut Pasteur, Université Paris Cité, Paris, France
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Vahedi-Shahandashti R, Stubenböck MM, Lass-Flörl C. The Influence of Medium Composition on EUCAST and Etest Antifungal Susceptibility Testing. J Fungi (Basel) 2023; 9:973. [PMID: 37888229 PMCID: PMC10608067 DOI: 10.3390/jof9100973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 09/25/2023] [Accepted: 09/25/2023] [Indexed: 10/28/2023] Open
Abstract
There is an ongoing effort to optimize and revise antifungal susceptibility testing (AFST) methods due to the rising number of fungal infections and drug-resistant fungi. The rising antifungal resistance within Candida and Aspergillus species, which are common contributors to invasive fungal infections (IFIs), is a cause for concern, prompting an expanding integration of in vitro AFST to guide clinical decisions. To improve the relevance of in vitro AFST results to therapy outcomes, influential factors should be taken into account. The tested medium is one of several factors that could affect the results of AFST. The present study evaluated the effect of two complex media (Sabouraud dextrose and Columbia) versus the standard defined medium (RPMI 1640) on the AFST results of amphotericin B, posaconazole, and voriconazole against Candida spp. and Aspergillus spp. representatives, utilizing the European Committee on Antimicrobial Susceptibility Testing (EUCAST) and the Etest methods. Overall, Candida species exhibited higher variability in minimum inhibitory concentration (MIC) across different media (more than three log2 dilutions) comparing to Aspergillus spp., while quality control isolates showed consistency regardless of tested media, antifungals, and methods. When comparing tested methods, MIC variation was mostly detected using EUCAST than it was using Etest.
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Affiliation(s)
| | | | - Cornelia Lass-Flörl
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (R.V.-S.)
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3
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Behiry SI, Al-Askar AA, Soliman SA, Alotibi FO, Basile A, Abdelkhalek A, Elsharkawy MM, Salem MZM, Hafez EE, Heflish AA. Plantago lagopus extract as a green fungicide induces systemic resistance against Rhizoctonia root rot disease in tomato plants. FRONTIERS IN PLANT SCIENCE 2022; 13:966929. [PMID: 36003819 PMCID: PMC9393307 DOI: 10.3389/fpls.2022.966929] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Accepted: 07/19/2022] [Indexed: 06/15/2023]
Abstract
Extensive use of chemical control agents and fungicides typically leads to numerous risks to human health and the environment. Using plant extracts as natural substances represents a dual key for the environment and sustainable food production, as it reduces the input of synthetic pesticides into the environment and/or controls plant pathogens. For the first time, a Plantago lagopus ethanolic extract has been characterized and evaluated for its protective and curative effects against Rhizoctonia solani in tomato plants. The results showed that P. lagopus extract (10 μg/ml) completely inhibited R. solani mycelial growth in vitro. At 20 days of post fungal inoculation, the results demonstrated that using P. lagopus extract (100 μg/ml) in vivo enhanced tomato plant growth by significantly increasing shoot and root parameters in protective and curative treatments. Furthermore, the protective and curative treatments significantly reduced the disease index by 18.66 and 38.66%, respectively. Induction of systemic resistance with upregulation of PR-1 and PR-2 and a significant increase in the transcriptional levels of PR-3 and CHS in all P. lagopus extract-treated tomato plants were reported compared to untreated plants. HPLC analysis showed that the most common polyphenolic components detected in P. lagopus extract were rutin (74206.3 mg/kg), naringenin (2388.74 mg/kg), quercetin (1249.13 mg/kg), and p-hydroxybenzoic acid (1035.87 mg/kg). In addition, the ellagic acid (798.47 mg/kg), vanillic acid (752.55 mg/kg), catechol (648.89 mg/kg), cinnamic acid (332.51 mg/kg), ferulic acid (296.32 mg/kg), benzoic acid (295.95 mg/kg), and chlorogenic acid (116.63 mg/kg) were also reported. Our study is the first to show that P. lagopus extract can help plants fight off R. solani fungal infection. Furthermore, the findings imply that using the P. lagopus extract as a natural biocontrol agent could be a sustainable strategy to manage plant fungal diseases.
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Affiliation(s)
- Said I. Behiry
- Department of Agricultural Botany, Faculty of Agriculture (Saba Basha), Alexandria University, Alexandria, Egypt
| | - Abdulaziz A. Al-Askar
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Seham A. Soliman
- Department of Plant Protection and Biomolecular Diagnosis, ALCRI, City of Scientific Research and Technological Applications, Alexandria, Egypt
| | - Fatimah O. Alotibi
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Adriana Basile
- Department of Biology, University of Naples Federico II, Naples, Italy
| | - Ahmed Abdelkhalek
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Mohsen Mohamed Elsharkawy
- Department of Agricultural Botany, Faculty of Agriculture, Kafrelsheikh University, Kafr El-Sheikh, Egypt
| | - Mohamed Z. M. Salem
- Department of Forestry and Wood Technology, Faculty of Agriculture (El-Shatby), Alexandria University, Alexandria, Egypt
| | - Elsayed E. Hafez
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Ahmed A. Heflish
- Department of Agricultural Botany, Faculty of Agriculture (Saba Basha), Alexandria University, Alexandria, Egypt
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Kidd SE, Crawford LC, Halliday CL. Antifungal Susceptibility Testing and Identification. Infect Dis Clin North Am 2021; 35:313-339. [PMID: 34016280 DOI: 10.1016/j.idc.2021.03.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The requirement for antifungal susceptibility testing is increasing given the availability of new drugs, increasing populations of individuals at risk for fungal infection, and emerging multiresistant fungi. Rapid and accurate fungal identification remains at the forefront of laboratory efforts to guide empiric therapy. Antifungal susceptibility testing methods have greatly improved, but are subject to variation in results between methods. Careful standardization, validation, and extensive training of users is essential to ensure susceptibility results are clinically useful and interpreted appropriately. Interpretive criteria for many drugs and species are still lacking, but this will continue to evolve.
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Affiliation(s)
- Sarah E Kidd
- National Mycology Reference Centre, Microbiology & Infectious Diseases, SA Pathology, SA Pathology (Frome Campus), PO Box 14, Rundle Mall, Adelaide, South Australia 5000, Australia; School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia.
| | - Lucy C Crawford
- Microbiology & Infectious Diseases, SA Pathology, PO Box 14, Rundle Mall, Adelaide, South Australia 5000, Australia; Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Catriona L Halliday
- Clinical Mycology Reference Laboratory, Centre for Infectious Diseases and Microbiology Laboratory Services, Institute of Clinical Pathology and Medical Research, NSW Health Pathology, Westmead Hospital, The University of Sydney, Level 3 ICPMR, Darcy Road, Westmead, New South Wales 2145, Australia
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5
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Carvalho ÂR, Genz Bazana LC, Ferrão MF, Fuentefria AM. Curve fitting and linearization of UV-Vis spectrophotometric measurements to estimate yeast in inoculum preparation. Anal Biochem 2021; 625:114216. [PMID: 33933444 DOI: 10.1016/j.ab.2021.114216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 03/24/2021] [Accepted: 04/16/2021] [Indexed: 11/29/2022]
Abstract
The counting of microorganisms is essential in the area of microbiology, especially in the preparation of inoculum. The main methods for obtaining inoculum are McFarland standard, Neubauer chamber, and plate count. However, the visual comparison is subjective while the counting in the chamber and the plating are technically time-consuming. For this reason, our article aims to correlate the absorbance of the spectrophotometer in the visible ultraviolet region (UV-Vis) with the cell counting in the Neubauer chamber. This study used suspensions of Candida spp. measured at three wavelengths (530, 600, and 700 nm) and counting in a Neubauer chamber. In the next step, curves were adjusted with different polynomials using absorbances and counts. The two best polynomial curve fittings were the Saturation Growth Rate (SGR) and Morgan-Mercer-Flodin (MMF). Therefore, the polynomials were linearized and a direct correlation between absorbance and the number of cells was made. The proposed method proved to be more accurate (5 ± 0.5 × 106) than the comparison with the McFarland turbidity (1-5 x 106) and more practical than plate counting. Predicting the number of cells by UV-Vis is an alternative that reduces the uncertainty of the cell count interval for inoculum preparation.
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Affiliation(s)
- Ânderson Ramos Carvalho
- Laboratório de Pesquisa em Micologia Aplicada, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil; Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.
| | - Luana Candice Genz Bazana
- Laboratório de Pesquisa em Micologia Aplicada, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil; Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Marco Flôres Ferrão
- Programa de Pós-Graduação em Química, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 91501-970, Brazil
| | - Alexandre Meneghello Fuentefria
- Laboratório de Pesquisa em Micologia Aplicada, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil; Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
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6
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Abdelkhalek A, Salem MZM, Hafez E, Behiry SI, Qari SH. The Phytochemical, Antifungal, and First Report of the Antiviral Properties of Egyptian Haplophyllum tuberculatum Extract. BIOLOGY 2020; 9:E248. [PMID: 32854351 PMCID: PMC7565794 DOI: 10.3390/biology9090248] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 08/17/2020] [Accepted: 08/22/2020] [Indexed: 11/30/2022]
Abstract
In this study, ethanol whole plant extract (WPE) of Haplophyllum tuberculatum was characterized and tested for its antifungal and antiviral activities against Fusarium culmorum, Rhizoctonia solani and tobacco mosaic virus (TMV). High Performance Liquid Chromatography (HPLC) analysis showed that the main phytochemical constituents of H. tuberculatum WPE were resveratrol (5178.58 mg/kg), kaempferol (1735.23 mg/kg), myricetin (561.18 mg/kg), rutin (487.04 mg/kg), quercetin (401.04 mg/kg), and rosmarinic acid (387.33 mg/kg). By increasing H. tuberculatum WPE at concentrations of 1%, 2%, and 3%, all of the fungal isolates were suppressed compared to the two positive and negative controls. Under greenhouse conditions, WPE-treated Chenopodium amaranticolor plants strongly inhibited TMV infection and significantly reduced TMV accumulation levels when compared to non-treated plants. Moreover, the induction of systemic resistance with significant increases in the transcriptional levels of the pathogenesis-related protein-1 (PR-1), chalcone synthase (CHS), and hydroxycinnamoyl-CoA quinate transferase (HQT) genes for treated plants were noticed at 3 and 5 days post-inoculation (dpi) for both assays. To the best of our knowledge, this is the first reported observation of the antiviral activity of H. tuberculatum extract against plant viral infections. Finally, the results obtained suggest that H. tuberculatum WPE can be considered a promising source of both antifungal and antiviral substances for practical use and for developing plant-derived compounds for the effective management of plant diseases.
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Affiliation(s)
- Ahmed Abdelkhalek
- Plant Protection and Biomolecular Diagnosis Department, ALCRI, City of Scientific Research and Technological Applications, New Borg El Arab, Alexandria 21934, Egypt;
| | - Mohamed Z. M. Salem
- Forestry and Wood Technology Department, Faculty of Agriculture (El-Shatby), Alexandria University, Alexandria 21545, Egypt
| | - Elsayed Hafez
- Plant Protection and Biomolecular Diagnosis Department, ALCRI, City of Scientific Research and Technological Applications, New Borg El Arab, Alexandria 21934, Egypt;
| | - Said I. Behiry
- Agricultural Botany Department, Faculty of Agriculture (Saba Basha), Alexandria University, Alexandria 21531, Egypt;
| | - Sameer H. Qari
- Biology Department, Al-Jumum University College, Umm Al-Qura University, Mecca 25376, Saudi Arabia;
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Vande Velde G, Kucharíková S, Van Dijck P, Himmelreich U. Bioluminescence imaging increases in vivo screening efficiency for antifungal activity against device-associated Candida albicans biofilms. Int J Antimicrob Agents 2018; 52:42-51. [DOI: 10.1016/j.ijantimicag.2018.03.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 03/01/2018] [Accepted: 03/11/2018] [Indexed: 11/29/2022]
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8
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Kidd SE, Halliday CL, Morris AJ, Chen SCA. Antifungal susceptibility testing in Australasian clinical laboratories: we must improve our performance. Pathology 2018; 50:257-260. [DOI: 10.1016/j.pathol.2018.01.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Revised: 01/25/2018] [Accepted: 01/30/2018] [Indexed: 10/17/2022]
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Maheronnaghsh M, Tolouei S, Dehghan P, Chadeganipour M, Yazdi M. Identification of Candida species in patients with oral lesion undergoing chemotherapy along with minimum inhibitory concentration to fluconazole. Adv Biomed Res 2016; 5:132. [PMID: 27656601 PMCID: PMC5025917 DOI: 10.4103/2277-9175.187394] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 06/15/2015] [Indexed: 02/02/2023] Open
Abstract
Background: Various species of Candida, especially Candida albicans was known as the most important etiological agent of fungal infections. Oral candidiasis is the most common fungal infection in patients undergoing chemotherapy. The purpose of this study was to identify Candida species from oral lesions of these patients and antifungal susceptibility of the clinical isolates. Materials and Methods: Among 385 patients with cancer, 55 (14.3%) showed oral lesions. Oral swabs were performed to identify the yeasts using direct smear and CHROMagar medium. Micro dilution method was prepared in different concentrations of fluconazole and minimum inhibitory concentration and minimum fungicidal concentration of each species were compared. Results: Oral candidiasis confirmed in 36 cases by direct examination and culture. C. albicans and non-albicans represented in 26 (72.2%) and 10 (27.8%) of the isolates, respectively. 76.5% of C. albicans and 23.5% non-albicans isolates were resistant to fluconazole. Data were shown that 62% and 30.7% of resistant strains of C. albicans were found in patient with gastrointestinal cancer and lymphoma respectively. Conclusion: Data were shown that C. albicans is the most commonly identified species in oral candidiasis and majority of fluconazole resistant C. albicans were found in patients with gastrointestinal cancer and lymphoma. Therefore, we recommend an alternative drug instead of fluconazole as a first line of treatment for these type of cancers and administration of fluconazole in patients undergoing chemotherapy should be prescribed in accordance with the type of cancer.
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Affiliation(s)
- Mehrnoush Maheronnaghsh
- Department of Parasitology and Mycology, School of Medicine, Faculty of Health, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Sepideh Tolouei
- Department of Parasitology and Mycology, School of Medicine, Faculty of Health, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Parvin Dehghan
- Department of Parasitology and Mycology, School of Medicine, Faculty of Health, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mostafa Chadeganipour
- Department of Parasitology and Mycology, School of Medicine, Faculty of Health, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Maryam Yazdi
- Department of Biostatistics and Epidemiology, Faculty of Health, Isfahan University of Medical Sciences, Isfahan, Iran
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Thatai P, Sapra B. Critical review on retrospective and prospective changes in antifungal susceptibility testing for dermatophytes. Mycoses 2016; 59:615-27. [DOI: 10.1111/myc.12514] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 04/19/2016] [Accepted: 04/19/2016] [Indexed: 11/30/2022]
Affiliation(s)
- Purva Thatai
- Division of Pharmaceutics; Department of Pharmaceutical Sciences; Punjabi University; Patiala India
| | - Bharti Sapra
- Division of Pharmaceutics; Department of Pharmaceutical Sciences; Punjabi University; Patiala India
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Marcos-Zambrano LJ, Escribano P, Sánchez-Carrillo C, Bouza E, Guinea J. Scope and frequency of fluconazole trailing assessed using EUCAST in invasive Candida spp. isolates. Med Mycol 2016; 54:733-9. [PMID: 27161788 DOI: 10.1093/mmy/myw033] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 03/23/2016] [Indexed: 11/14/2022] Open
Abstract
Trailing is a well-known phenomenon that is defined as reduced but persistent visible growth of Candida spp. at fluconazole concentrations above the MIC. Trailing is commonly detected using the CLSI M27-A3 method, although little is known about its frequency when investigated with EUCAST. We assessed the frequency and scope of fluconazole trailing after using EUCAST EDef 7.2. against a large number of Candida spp. isolates from patients with candidemia. We studied 639 fluconazole-susceptible non-krusei Candida spp. isolates from 570 patients admitted to Gregorio Marañón Hospital. Isolates were tested in vitro for fluconazole susceptibility according to the EUCAST EDef 7.2 procedure; trailing was defined as the presence of any residual growth in wells containing fluconazole concentrations above the MIC. According to the mean percentage of trailing observed, isolates were classified as residual trailers (0.1-5%), slight trailers (6%-10%), moderate trailers (11%-15%), and heavy trailers (>15%). The relationship between trailing and genotyping was assessed. The mean overall percentage of trailing was 6.8%, with C. albicans and C. tropicalis showing the highest percentages (9.75% and 9.29%, respectively; P < .001). C. albicans and C. tropicalis had the highest percentage of heavy trailers (>15%). Trailing was not genotype-specific. Fluconazole trailing was observed frequently when EUCAST was used for antifungal susceptibility testing, particularly in isolates of C. albicans and C. tropicalis The cut-off proposed enabled us to classify the isolates according to the degree of trailing and can be used as the basis for future studies to evaluate the clinical impact of this phenomenon.
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Affiliation(s)
- Laura Judith Marcos-Zambrano
- Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
| | - Pilar Escribano
- Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain CIBER Enfermedades Respiratorias-CIBERES (CB06/06/0058), Madrid, Spain
| | - Carlos Sánchez-Carrillo
- Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain CIBER Enfermedades Respiratorias-CIBERES (CB06/06/0058), Madrid, Spain
| | - Emilio Bouza
- Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain CIBER Enfermedades Respiratorias-CIBERES (CB06/06/0058), Madrid, Spain Medicine Department, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain
| | - Jesús Guinea
- Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain CIBER Enfermedades Respiratorias-CIBERES (CB06/06/0058), Madrid, Spain Medicine Department, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain
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Rizi K, Murdan S, Danquah CA, Faull J, Bhakta S. Development of a rapid, reliable and quantitative method — “SPOTi” for testing antifungal efficacy. J Microbiol Methods 2015; 117:36-40. [DOI: 10.1016/j.mimet.2015.07.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Revised: 07/02/2015] [Accepted: 07/02/2015] [Indexed: 10/23/2022]
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13
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Nachimuthu N, Ostrosky-Zeichner L. Antifungal Susceptibility Testing: Evolution, Indications, and Role in Clinical Practice. CURRENT TREATMENT OPTIONS IN INFECTIOUS DISEASES 2015. [DOI: 10.1007/s40506-015-0056-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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14
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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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15
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Cryptococcus neoformans meningoencephalitis in a patient with polyarteritis nodosa. Folia Microbiol (Praha) 2014; 59:515-21. [PMID: 24947767 DOI: 10.1007/s12223-014-0328-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 06/11/2014] [Indexed: 10/25/2022]
Abstract
Case of 59-year-old male with chronic obstructive pulmonary disease and a number of comorbidities, who has developed meningoencephalitis caused by Cryptococcus neoformans var. grubii with polyarteritis nodosa diagnosed during hospitalization, was presented. Before evidence of meningoencephalitis, the patient was being treated with ketoconazole and low doses of fluconazole (200 mg/day) for alleged candidiasis. The dosage was increased (800 mg/day) following laboratory diagnosis of C. neoformans based on positive latex agglutination test and biochemical identification of encapsulated yeast isolated from the blood and CSF. Later, the yeast identification was confirmed by sequencing analysis. Owing to inadequate clinical response, fluconazole therapy was switched to voriconazole (400 mg/day) and later to intravenous amphotericin B (1.0 mg/kg per day). Despite of a temporary stabilization and improvement, which correlated with decline of cryptococcal antigen titers (from 1:1024 to 1:8), after 6 weeks, the patient's underlying condition deteriorated due to severe pancolitis and serious nosocomial bacterial infections. The patient died of multiorgan failure several days later. Our case demonstrates a possible connection between the development of life-threatening cryptococcosis and an autoimmune vasculitis disease and emphasizes that the outcome of the management of cryptococcal meningoencephalitis is highly dependent on early diagnosis, adequate treatment, including dosage, and last but not least control of underlying disease and risk factors.
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Cruz I, Cheetham JJ, Arnason JT, Yack JE, Smith ML. Alkamides from Echinacea disrupt the fungal cell wall-membrane complex. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2014; 21:435-442. [PMID: 24252333 DOI: 10.1016/j.phymed.2013.10.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 08/15/2013] [Accepted: 10/17/2013] [Indexed: 06/02/2023]
Abstract
We tested the hypothesis that alkamides from Echinacea exert antifungal activity by disrupting the fungal cell wall/membrane complex. Saccharomyces cerevisiae cells were treated separately with each of seven synthetic alkamides found in Echinacea extracts. The resulting cell wall damage and cell viability were assessed by fluorescence microscopy after mild sonication. Membrane disrupting properties of test compounds were studied using liposomes encapsulating carboxyfluorescein. Negative controls included hygromycin and nourseothricin (aminoglycosides that inhibit protein synthesis), and the positive control used was caspofungin (an echinocandin that disrupts fungal cell walls). The results show that yeast cells exposed to sub-inhibitory concentrations of each of the seven alkamides and Echinacea extract exhibit increased frequencies of cell wall damage and death that were comparable to caspofungin and significantly greater than negative controls. Consistent with effects of cell wall damaging agents, the growth inhibition by three representative alkamides tested and caspofungin, but not hygromycin B, were partially reversed in sorbitol protection assays. Membrane disruption assays showed that the Echinacea extract and alkamides have pronounced membrane disruption activity, in contrast to caspofungin and other controls that all had little effect on membrane stability. A Quantitative Structure-Activity Relationship (QSAR) analysis was performed to study the effect of structural substituents on the antifungal activity of the alkamides. Among the set studied, diynoic alkamides showed the greatest antifungal and cell wall disruption activities while an opposite trend was observed in the membrane disruption assay where the dienoic group was more effective. We propose that alkamides found in Echinacea act synergistically to disrupt the fungal cell wall/membrane complex, an excellent target for specific inhibition of fungal pathogens. Structure-function relationships provide opportunities for synthesis of alkamide analogs with improved antifungal activities.
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Affiliation(s)
- I Cruz
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada
| | - J J Cheetham
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada
| | - J T Arnason
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, Ontario K1N 6N5, Canada
| | - J E Yack
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada
| | - M L Smith
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada.
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Inhibition of conidiophore development in Aspergillus fumigatus by an Escherichia coli DH5α strain, a promising antifungal candidate against aspergillosis. J Mycol Med 2014; 24:1-12. [DOI: 10.1016/j.mycmed.2013.07.055] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2013] [Revised: 06/23/2013] [Accepted: 07/18/2013] [Indexed: 11/21/2022]
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18
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Sen A, Gurbuz B, Gurer US, Bulut G, Bitis L. Flavonoids and Biological Activities of Centaurea stenolepis. Chem Nat Compd 2014. [DOI: 10.1007/s10600-014-0886-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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19
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Wong SSW, Kao RYT, Yuen KY, Wang Y, Yang D, Samaranayake LP, Seneviratne CJ. In vitro and in vivo activity of a novel antifungal small molecule against Candida infections. PLoS One 2014; 9:e85836. [PMID: 24465737 PMCID: PMC3899067 DOI: 10.1371/journal.pone.0085836] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 12/02/2013] [Indexed: 12/01/2022] Open
Abstract
Candida is the most common fungal pathogen of humans worldwide and has become a major clinical problem because of the growing number of immunocompromised patients, who are susceptible to infection. Moreover, the number of available antifungals is limited, and antifungal-resistant Candida strains are emerging. New and effective antifungals are therefore urgently needed. Here, we discovered a small molecule with activity against Candida spp. both in vitro and in vivo. We screened a library of 50,240 small molecules for inhibitors of yeast-to-hypha transition, a major virulence attribute of Candida albicans. This screening identified 20 active compounds. Further examination of the in vitro antifungal and anti-biofilm properties of these compounds, using a range of Candida spp., led to the discovery of SM21, a highly potent antifungal molecule (minimum inhibitory concentration (MIC) 0.2 – 1.6 µg/ml). In vitro, SM21 was toxic to fungi but not to various human cell lines or bacterial species and was active against Candida isolates that are resistant to existing antifungal agents. Moreover, SM21 was relatively more effective against biofilms of Candida spp. than the current antifungal agents. In vivo, SM21 prevented the death of mice in a systemic candidiasis model and was also more effective than the common antifungal nystatin at reducing the extent of tongue lesions in a mouse model of oral candidiasis. Propidium iodide uptake assay showed that SM21 affected the integrity of the cell membrane. Taken together, our results indicate that SM21 has the potential to be developed as a novel antifungal agent for clinical use.
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Affiliation(s)
| | - Richard Yi Tsun Kao
- Department of Microbiology, University of Hong Kong, Hong Kong
- * E-mail: (CJS); (RYTK)
| | - Kwok Yong Yuen
- Department of Microbiology, University of Hong Kong, Hong Kong
| | - Yu Wang
- Department of Pharmacology & Pharmacy, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong
| | - Dan Yang
- Department of Chemistry, Faculty of Science, University of Hong Kong, Hong Kong
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20
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Pharmacokinetics of fluconazole following intravenous and oral administration to koalas (Phascolarctos cinereus
). J Vet Pharmacol Ther 2013; 37:90-8. [DOI: 10.1111/jvp.12072] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 07/05/2013] [Indexed: 11/26/2022]
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21
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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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22
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Kuper KM, Coyle EA, Wanger A. Antifungal Susceptibility Testing: A Primer for Clinicians. Pharmacotherapy 2012; 32:1112-22. [DOI: 10.1002/phar.1146] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Kristi M. Kuper
- Department of Quality Services; Cardinal Health; Houston; Texas
| | | | - Audrey Wanger
- Department of Pathology; University of Texas Medical School; Houston; Texas
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23
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A screening assay based on host-pathogen interaction models identifies a set of novel antifungal benzimidazole derivatives. Antimicrob Agents Chemother 2011; 55:4789-801. [PMID: 21746957 DOI: 10.1128/aac.01657-10] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fungal infections are a serious health problem in clinics, especially in the immune-compromised patient. Disease ranges from widespread superficial infections like vulvovaginal infections to life-threatening systemic candidiasis. Especially for systemic mycoses, only a limited arsenal of antifungals is available. The most commonly used classes of antifungal compounds used include azoles, polyenes, and echinocandins. Due to emerging resistance to standard therapy, significant side effects, and high costs for several antifungals, there is a medical need for new antifungals in the clinic and general practice. In order to expand the arsenal of compounds with antifungal activities, we screened a compound library including more than 35,000 individual compounds derived from organic synthesis as well as combinatorial compound collections representing mixtures of compounds for antimycotic activity. In total, more than 100,000 compounds were screened using a new type of activity-selectivity assay, analyzing both the antifungal activity and the compatibility with human cells at the same time. One promising hit, an (S)-2-aminoalkyl benzimidazole derivative, was developed among a series of lead compounds showing potent antifungal activity. (S)-2-(1-Aminoisobutyl)-1-(3-chlorobenzyl) benzimidazole showed the highest antifungal activity and the best compatibility with human cells in several cell culture models and against a number of clinical isolates of several species of pathogenic Candida yeasts. Transcriptional profiling indicates that the newly discovered compound is a potential inhibitor of the ergosterol pathway, in contrast to other benzimidazole derivatives, which target microtubules.
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24
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Manastır L, Ergon MC, Yücesoy M. Investigation of mutations in Erg11 gene of fluconazole resistant Candida albicans isolates from Turkish hospitals. Mycoses 2011; 54:99-104. [PMID: 19732347 DOI: 10.1111/j.1439-0507.2009.01766.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Widespread use of fluconazole has resulted in resistance in strains of Candida. The aim of our study was to investigate Y132H and other mutations in the ERG11 gene in conferring fluconazole resistance to C. albicans isolates. Seven fluconazole-resistant (R)/susceptible dose-dependent (SDD)/trailing and 10 fluconazole-susceptible (S) isolates were included. Restriction enzyme analysis was performed on all isolates for Y132H mutation and sequence analysis was performed for other mutations in the ERG11 gene. None of our strains had Y132H mutation. One single mutation (D153E, E266D, D116E, V437I) was detected in isolates 348, 533, 644, 1453, 2157, while the others had more than one nucleotide change. D116E and E266D, which were two mutations found in fluconazole R/SDD/trailing isolates with the highest frequency, were also detected in azole S strains. K143R, G464S, G465S and V488I mutations were determined in three of the R/SDD isolates. S412T and R469K mutations were detected only in this group of strains by sequence analysis. Mutations such as K143R, G464S, G465S, V488I, S412T and R469K in the ERG11 gene were determined to be effective mechanisms in our fluconazole R/SDD C. albicans isolates. Other mechanisms of resistance, such as overexpression of ERG11 and efflux pumps and mutations in the ERG3 gene should also be investigated.
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Affiliation(s)
- Lerzan Manastır
- Department of Microbiology and Clinical Microbiology, School of Medicine, Dokuz Eylul University, Inciralti, Izmir, Turkey
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25
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Arseculeratne SN, Eriyagama NB. Comparison of in vivo and in vitro inactivation of endospores of Rhinosporidium seeberi following dapsone treatment. MYCOSCIENCE 2011. [DOI: 10.1007/s10267-010-0079-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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26
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Nyilasi I, Kocsubé S, Krizsán K, Galgóczy L, Pesti M, Papp T, Vágvölgyi C. In vitro synergistic interactions of the effects of various statins and azoles against some clinically important fungi. FEMS Microbiol Lett 2010; 307:175-84. [PMID: 20636975 DOI: 10.1111/j.1574-6968.2010.01972.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The treatment of opportunistic fungal infections is often difficult as the number of available antifungal agents is limited. Nowadays, there is increasing interest in the investigation of the antifungal activity of nonantifungal drugs, and in the development of efficient antifungal combination therapy. In this study, the in vitro interactions of the effects of various statins (lovastatin, simvastatin, fluvastatin, atorvastatin (ATO), rosuvastatin (ROS) and pravastatin) and various azole antifungals [miconazole, ketoconazole, itraconazole and fluconazole (FLU)] against different opportunistic pathogenic fungi were investigated using a standard chequerboard broth microdilution method. When the investigated strains were sensitive to both compounds of the combination, additive interactions were frequently noticed. Synergistic interactions were observed in many cases when a strain was sensitive only to the azole compound (as in certain combinations with ATO or ROS) or the statin compound (as in certain combinations with FLU). In many combinations with an additive effect, the concentrations of drugs needed for total growth inhibition could be decreased by several dilution steps. Similar interactions were observed when the variability of the within-species sensitivities to some selected drug combinations was investigated.
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Affiliation(s)
- Ildikó Nyilasi
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary.
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27
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Lass-Flörl C. In vitro susceptibility testing in Aspergillus species: an update. Future Microbiol 2010; 5:789-99. [PMID: 20441550 DOI: 10.2217/fmb.10.34] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aspergillus species are the most common causes of invasive mold infections in immunocompromised patients. The introduction of new antifungal agents and recent reports of resistance emerging during treatment of Aspergillus infections have highlighted the need for in vitro susceptibility testing. Various testing procedures have been proposed, including macro- and micro-dilution, disk diffusion, Etest (AB Biodisk, Sweden) and other commercial tests. Although Aspergillus species are generally susceptible to various compounds, intrinsic and acquired resistance has been documented. Amphotericin B has limited activity against Aspergillus terreus and Aspergillus nidulans. Not surprisingly, continued use of azole-based drugs has the undesirable consequence of elevating the resistance of subsequent isolates from these patients. Several species in the Aspergillus fumigatus complex appear to be resistant to azoles; there is evidence of in vitro and in vivo correlation. Each in vitro susceptibility testing method has its own advantages and disadvantages. Etest is easy to perform and use on a daily basis, yet it is expensive. Disk diffusion is the most attractive alternative method to date, yet we lack sufficient data for aspergilli. The European Committee on Antimicrobial Susceptibility Testing (EUCAST) and the Clinical Laboratory Standard Institute (CLSI) have produced reproducible reference testing methods. This article reviews the available methods for antifungal susceptibility testing in Aspergillus spp. as well as the scant data regarding the clinical implications of in vitro testing.
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Affiliation(s)
- Cornelia Lass-Flörl
- Department of Hygiene, Microbiology & Social Medicine, Division of Hygiene & Clinical Microbiology, Innsbruck Medical University, Fritz Pregl Str 3, 6020 Innsbruck, Austria.
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28
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T-2307 shows efficacy in a murine model of Candida glabrata infection despite in vitro trailing growth phenomena. Antimicrob Agents Chemother 2010; 54:3630-4. [PMID: 20547803 DOI: 10.1128/aac.00355-10] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
T-2307, a novel arylamidine, has been shown to exhibit broad-spectrum in vitro and in vivo antifungal activities against clinically significant pathogens. In our preliminary studies, Candida glabrata exhibited significant trailing growth (partial inhibition of growth over an extended range of antifungal concentrations) in the presence of T-2307 when it was tested using the Clinical and Laboratory Standards Institute (CLSI) guidelines with 0.2% glucose and 48 h of incubation, making reading of the MIC difficult. In the present study, we attempted to attenuate trailing growth to avoid misreading of the MIC. On the basis of the hypothesis that T-2307 may inhibit the mitochondrial functions of cells, the carbon source or the glucose concentration in the medium was changed. The trailing growth of C. glabrata ATCC 90030 in the presence of T-2307 was attenuated as the concentration of glucose in the medium decreased to 0.1% or lower, and trailing growth was completely inhibited when glycerol was used. A susceptibility test using Alamar blue was performed to facilitate reading of the MIC without changing the composition of the medium and provided a clear MIC endpoint at 24 h. To investigate if T-2307 shows efficacy against trailing isolates in vivo, we evaluated the efficacy of T-2307 in a murine model of disseminated candidiasis caused by C. glabrata. T-2307 at 0.05 mg/kg of body weight/day significantly decreased the viable count in the kidneys compared to that for the control group (P < 0.05). It would be better to test the susceptibility of C. glabrata to T-2307 using modified media or Alamar blue to avoid misreading of the MIC due to the significant trailing growth.
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29
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Ramos-e-Silva M, Lima CMO, Schechtman RC, Trope BM, Carneiro S. Superficial mycoses in immunodepressed patients (AIDS). Clin Dermatol 2010; 28:217-25. [DOI: 10.1016/j.clindermatol.2009.12.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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30
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Lass-Flörl C, Perkhofer S, Mayr A. In vitro susceptibility testing in fungi: a global perspective on a variety of methods. Mycoses 2010; 53:1-11. [PMID: 20078786 DOI: 10.1111/j.1439-0507.2009.01813.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Candida and Aspergillus species are the most common causes of invasive fungal infections in immunocompromised patients. The introduction of new antifungal agents and recent reports of resistance emerging during treatment have highlighted the need for in vitro susceptibility testing. For some drugs, there is a supporting in vitro-in vivo correlation available from studies of clinical efficacy. Both intrinsic and emergent antifungal drug resistance are encountered. Various testing procedures have been proposed, including macrodilution and microdilution, agar diffusion, disk diffusion and Etest. Early recognition of infections caused by pathogens that are resistant to one or more antifungals is highly warranted to optimise treatment and patient outcome.
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Affiliation(s)
- Cornelia Lass-Flörl
- Department of Hygiene, Microbiology and Social Medicine, Division of Hygiene and Medical Microbiology, Innsbruck Medical University, Innsbruck, Austria.
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31
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Pharmacokinetic and Toxicokinetic Studies of Potential Antifungal Compounds, KAF-200522 and KAF-200522 · HCl, in Animal Models. Lab Anim Res 2010. [DOI: 10.5625/lar.2010.26.4.399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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32
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Odabasi Z, Paetznick VL, Rodriguez JR, Chen E, Rex JH, Leitz GJ, Ostrosky-Zeichner L. Lack of correlation of 24- vs. 48-h itraconazole minimum inhibitory concentrations with microbiological and survival outcomes in a guinea pig model of disseminated candidiasis. Mycoses 2009; 53:438-42. [PMID: 19500259 DOI: 10.1111/j.1439-0507.2009.01733.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
A 'trailing' effect has been commonly observed when azole antifungals are tested against Candida spp. Previous experience with fluconazole indicates that 24-h minimum inhibitory concentration (MIC) values are more compatible endpoints when compared with clinical outcomes. We evaluated the trailing effect of Candida isolates tested with itraconazole in a guinea pig model of systemic candidiasis. Survival and organ burden were only significantly affected by using a higher dose of itraconazole, irrespective of the MIC differences at 24 and 48 h. A fluconazole-resistant strain with susceptible dose-dependent MICs to itraconazole was successfully treated with high-dose itraconazole. Our data suggests that survival and microbiological response depend more on drug dosing than on the trailing phenotype of the isolates.
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Affiliation(s)
- Zekaver Odabasi
- Laboratory of Mycology Research, Division of Infectious Diseases, University of Texas, Houston Medical School, Houston, TX, USA.
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33
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Tan AL, Chan KS. In vitro Activities of Antifungal Drugs Against Yeasts Isolated from Blood Cultures and Moulds Isolated from Various Clinically Significant Sites in Singapore. ANNALS OF THE ACADEMY OF MEDICINE, SINGAPORE 2008. [DOI: 10.47102/annals-acadmedsg.v37n10p841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Introduction: Fungaemia carries with it high mortality rates and appropriate as well as timely antifungal therapy has been shown to be life saving.
Materials and Methods: We studied the invitro activities of antifungal agents using the Etest method, against 100 Candida isolates from blood cultures, 10 Cryptococcus isolates from blood or cerebrospinal fluid and 50 mould isolates from various clinically significant sites of patients in Singapore General Hospital, from June 2004 to December 2006.
Results: Overall, the yeasts appeared to have low minimum inhibitory concentrations (MICs) for all the 5 antifungal drugs tested except for fluconazole. The overall high MIC90 values of the moulds against the azoles were largely attributed to the non-Aspergillus moulds. Posaconazole, itraconazole, voriconazole and caspofungin appear effective against local strains of Aspergillus species, although there are no interpretive breakpoints.
Conclusions: The results show that the local fungal strains studied appear to be susceptible to the usual antifungal drugs recommended in the literature.
Key words: Antifungal susceptibility, Aspergillus, Candida, Etest, Singapore
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34
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Clément M, Tremblay J, Lange M, Thibodeau J, Belhumeur P. Purification and identification of bovine cheese whey fatty acids exhibiting in vitro antifungal activity. J Dairy Sci 2008; 91:2535-44. [PMID: 18565910 DOI: 10.3168/jds.2007-0806] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Milk lipids contain several bioactive factors exhibiting antimicrobial activity against bacteria, viruses, and fungi. In the present study, we demonstrate that free fatty acids (FFA) derived from the saponification of bovine whey cream lipids are active in vitro at inhibiting the germination of Candida albicans, a morphological transition associated with pathogenicity. This activity was found to be significantly increased when bovine FFA were enriched in non-straight-chain FFA. At low cell density, this non-straight-chain FFA-enriched fraction was also found to inhibit in a dose-dependant manner the growth of both developmental forms of C. albicans as well as the growth of Aspergillus fumigatus. Using an assay-guided fractionation, the main components responsible for these activities were isolated. On the basis of mass spectroscopic and gas chromatographic analysis, antifungal compounds were identified as capric acid (C10:0), lauroleic acid (C12:1), 11-methyldodecanoic acid (iso-C13:0), myristoleic acid (C14:1n-5), and gamma-linolenic acid (C18:3n-6). The most potent compound was gamma-linolenic acid, with minimal inhibitory concentration values of 5.4 mg/L for C. albicans and 1.3 mg/L for A. fumigatus, in standardized conditions. The results of this study indicate that bovine whey contains bioactive fatty acids exhibiting antifungal activity in vitro against 2 important human fungal pathogens.
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Affiliation(s)
- M Clément
- Département de microbiologie et immunologie, Université de Montréal, C.P. 6128, succ. Centreville, Montréal, Québec, H3C 3J7, Canada.
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35
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36
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Koga-Ito CY, Lyon JP, Resende MAD. Comparison between E-test and CLSI broth microdilution method for antifungal susceptibility testing of Candida albicans oral isolates. Rev Inst Med Trop Sao Paulo 2008; 50:7-10. [DOI: 10.1590/s0036-46652008000100002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2006] [Accepted: 09/24/2007] [Indexed: 11/22/2022] Open
Abstract
Thirty Candida albicans isolated from oral candidosis patients and 30 C. albicans isolated from control individuals were studied. In vitro susceptibility tests were performed for amphotericin B, fluconazole, 5-flucytosine and itraconazole through the Clinical and Laboratorial Standards Institute (CLSI) reference method and E test system. The results obtained were analyzed and compared. MIC values were similar for the strains isolated from oral candidosis patients and control individuals. The agreement rate for the two methods was 66.67% for amphotericin B, 53.33% for fluconazole, 65% for flucytosine and 45% for itraconazole. According to our data, E test method could be an alternative to trial routine susceptibility testing due to its simplicity. However, it can not be considered a substitute for the CLSI reference method.
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37
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Sterling TR, Merz WG. Resistance to amphotericin B: emerging clinical and microbiological patterns. Drug Resist Updat 2007; 1:161-5. [PMID: 17092800 DOI: 10.1016/s1368-7646(98)80034-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/1998] [Revised: 03/11/1998] [Accepted: 03/24/1998] [Indexed: 11/16/2022]
Abstract
There has been an increasing number of reports of clinically significant amphotericin B (AmB) resistance in fungal pathogens, including Candida albicans. Concomitantly, advances in antifungal susceptibility testing have led to an improved correlation between microbiologic and clinical failure. Reports of AmB resistance, correlation of results and in vitro/in vivo correlations, mechanisms of resistance, and the transmission of resistant isolates within confined environments are reviewed. Recommendations are given regarding the clinical settings in which AmB susceptibility testing should be considered.
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Affiliation(s)
- T R Sterling
- Johns Hopkins University School of Medicine, Division of Infectious Diseases, Baltimore, MD 21287, USA
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38
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Perumal P, Mekala S, Chaffin WL. Role for cell density in antifungal drug resistance in Candida albicans biofilms. Antimicrob Agents Chemother 2007; 51:2454-63. [PMID: 17502416 PMCID: PMC1913227 DOI: 10.1128/aac.01237-06] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Biofilms of Candida albicans are less susceptible to many antifungal drugs than are planktonic yeast cells. We investigated the contribution of cell density to biofilm phenotypic resistance. Planktonic yeast cells in RPMI 1640 were susceptible to azole-class drugs, amphotericin B, and caspofungin at 1 x 10(3) cells/ml (standard conditions) using the XTT [2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide sodium salt] assay. As reported by others, as the cell concentration increased to 1 x 10(8) cells/ml, resistance was observed with 10- to 20-fold-greater MICs. Biofilms that formed in microtiter plate wells, like high-density planktonic organisms, were resistant to drugs. When biofilms were resuspended before testing, phenotypic resistance remained, but organisms, when diluted to 1 x 10(3) cells/ml, were susceptible. Drug-containing medium recovered from high-cell-density tests inhibited low-cell-density organisms. A fluconazole-resistant strain showed greater resistance at high planktonic cell density, in biofilm, and in resuspended biofilm than did low-density planktonic or biofilm organisms. A strain lacking drug efflux pumps CDR1, CDR2, and MDR1, while susceptible at a low azole concentration, was resistant at high cell density and in biofilm. A strain lacking CHK1 that fails to respond to the quorum-sensing molecule farnesol had the same response as did the wild type. FK506, reported to abrogate tolerance to azole drugs at low cell density, had no effect on tolerance at high cell density and in biofilm. These observations suggested that cell density has a role in the phenotypic resistance of biofilm, that neither the drug efflux pumps tested nor quorum sensing through Chk1p contributes to resistance, and that azole drug tolerance at high cell density differs mechanistically from tolerance at low cell density.
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Affiliation(s)
- Palani Perumal
- Department of Microbiology and Immunology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
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Abu-Elteen KH, Hamad MA, Kavanagh K. Epsilometer Test-Based Determination of Susceptibility of Clinically Important Candida Isolates to Conventional Antifungal Agents. JOURNAL OF MEDICAL SCIENCES 2007. [DOI: 10.3923/jms.2007.374.382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Betbeze CM, Wu CC, Krohne SG, Stiles J. In vitro fungistatic and fungicidal activities of silver sulfadiazine and natamycin on pathogenic fungi isolated from horses with keratomycosis. Am J Vet Res 2006; 67:1788-93. [PMID: 17014335 DOI: 10.2460/ajvr.67.10.1788] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To evaluate the in vitro antifungal properties of silver sulfadiazine (SSD) and natamycin against filamentous fungi isolated from eyes of horses with keratomycosis. SAMPLE POPULATION Filamentous fungal isolates obtained from eyes of keratomycosis-affected horses. PROCEDURES Fungal culture of ocular samples yielded 6 Fusarium spp; 7 Aspergillus spp; and 1 isolate each of Curvularia, Scopulariopsis, Penicillium, and Chrysosporium. For each fungal isolate, minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of SSD and natamycin were determined. RESULTS For all 17 fungal isolates, SSD MIC distribution ranged from < or = 1 to > 64 microg/mL; MIC50 and MIC90 (MICs at which 50% and 90% of organisms were inhibited) were 4 and 32 microg/mL, respectively. The SSD MFC distribution for all isolates was < or = 1 to > 64 microg/mL; MFC50 and MFC90 (MFCs at which 50% and 90% of organisms were killed) were 8 and > 64 microg/mL, respectively. For all fungal isolates, natamycin MIC distribution ranged from 256 to > 1,000 microg/mL; MIC50 and MIC90 were 512 and > 1,000 microg/mL, respectively. The natamycin MFC distribution for all isolates ranged from 512 to > 1,000 microg/mL; MFC(50) and MFC(90) were each > 1,000 microg/mL. CONCLUSIONS AND CLINICAL RELEVANCE These in vitro data suggest that SSD is fungicidal against the fungal isolates that were obtained from eyes of horses with keratomycosis and that natamycin is fungicidal against some of the isolates at the drug concentrations evaluated. Silver sulfadiazine may be a therapeutic option for equine keratomycosis.
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Affiliation(s)
- Caroline M Betbeze
- Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Purdue University, West Lafayette, IN 47907, 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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Maki K, Watabe E, Iguchi Y, Nakamura H, Tomishima M, Ohki H, Yamada A, Matsumoto S, Ikeda F, Tawara S, Mutoh S. Determination of antifungal activities in serum samples from mice treated with different antifungal drugs allows detection of an active metabolite of itraconazole. Microbiol Immunol 2006; 50:281-92. [PMID: 16625050 DOI: 10.1111/j.1348-0421.2006.tb03796.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
To establish an in vitro method of predicting in vivo efficacy of antifungal drugs against Candida albicans and Aspergillus fumigatus, the antifungal activities of fluconazole, itraconazole, and amphotericin B were determined in mouse serum. The minimum inhibitory concentration (MIC) of each drug was measured using mouse serum as a diluent. For C. albicans, the assay endpoint of azoles was defined as inhibition of mycelial extension (mMIC) and for A. fumigatus, as no growth (MIC). The MICs of amphotericin B for both pathogens were defined as the MIC at which no mycelial growth occurred. Serum MIC or mMIC determinations were then used to estimate the concentration of the drugs in serum of mice treated with antifungal drugs by multiplying the antifungal titer of the serum samples by the serum (m)MIC. The serum drug concentrations were also determined by HPLC. The serum concentrations estimated microbiologically showed good agreement with those determined by HPLC, except for itraconazole. Analysis of the serum samples from itraconazole-treated mice by a sensitive bioautography revealed the presence of additional spots, not seen in control samples of itraconazole. The bioautography assay demonstrated that the additional material detected in serum from mice treated with itraconazole was an active metabolite of itraconazole. The data showed that the apparent reduction in the itraconazole serum concentration as determined by HPLC was the result of the formation of an active metabolite, and that the use of a microbiological method to measure serum concentrations of drugs can provide a method for prediction of in vivo efficacy of antifungal drugs.
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Affiliation(s)
- Katsuyuki Maki
- Pharmacology Research Laboratories, Department of Infectious Diseases, Astellas Pharma, Inc, Osaka, Japan.
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Lass-Flörl C, Cuenca-Estrella M, Denning DW, Rodriguez-Tudela JL. Antifungal susceptibility testing in Aspergillus spp. according to EUCAST methodology. Med Mycol 2006; 44:S319-S325. [PMID: 30408924 DOI: 10.1080/13693780600779401] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
The availability of new antifungal agents has multiplied the demand for in vitro antifungal susceptibility testing for Aspergillus spp. The European Committee on Antimicrobial Susceptibility Testing (EUCAST) has charged its Antifungal Susceptibility Testing Subcommittee (AFST-EUCAST) with the preparation of new guidelines for in vitro susceptibility testing of antifungals against Aspergillus spp (EUCAST-AST-ASPERGILLUS). This committee has modified the reference method for broth dilution antifungal susceptibility testing of filamentous fungi (M38-A) as follows: (i) RPMI 1640 supplemented with 2% glucose (RPMI 2%G) as assay medium, (ii) inoculum preparation by conidium counting in a haemocytometer and (iii) an inoculum size of 2×105-5×105 CFU/ml. The incubation time is about 48 h at 35°C and MIC is read visually. The MIC value is a no-growth visual endpoint. The standard method described herein is intended to provide a valid and economic method for testing the susceptibility to antifungal agents of Aspergillus spp., to identify resistance, and to facilitate an acceptable degree of conformity, e.g. agreement within specified ranges and between laboratories in measuring the susceptibility.
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Affiliation(s)
- C Lass-Flörl
- Department of Hygiene and Clinical Microbiology, University of Innsbruck, Austria
| | - M Cuenca-Estrella
- Servicio de Micologia, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Spain
| | - D W Denning
- School of Medicine and Faculty of Life Sciences, University of Manchester, UK
| | - J L Rodriguez-Tudela
- Servicio de Micologia, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Spain
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Engelmeier D, Hadacek F. Chapter 17 Antifungal natural products: assays and applications. ADVANCES IN PHYTOMEDICINE 2006. [DOI: 10.1016/s1572-557x(06)03017-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Kartsonis N, Killar J, Mixson L, Hoe CM, Sable C, Bartizal K, Motyl M. Caspofungin susceptibility testing of isolates from patients with esophageal candidiasis or invasive candidiasis: relationship of MIC to treatment outcome. Antimicrob Agents Chemother 2005; 49:3616-23. [PMID: 16127030 PMCID: PMC1195423 DOI: 10.1128/aac.49.9.3616-3623.2005] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The caspofungin clinical trial database offers an opportunity to assess susceptibility results for Candida pathogens obtained from patients with candidiasis and allows for correlations between efficacy outcomes and MICs. Candida isolates have been identified from patients enrolled in four studies of esophageal candidiasis and two studies of invasive candidiasis. The MICs of caspofungin for all baseline isolates were measured at a central laboratory using NCCLS criteria (document M-27A); MICs for caspofungin were defined as the lowest concentration inhibiting prominent growth at 24 h. MICs were then compared to clinical and microbiological outcomes across the two diseases. Susceptibility testing for caspofungin was performed on 515 unique baseline isolates of Candida spp. obtained from patients with esophageal candidiasis. MICs for caspofungin ranged from 0.008 to 4 microg/ml; the MIC50 and MIC90 were 0.5 and 1.0 microg/ml, respectively. Susceptibility testing was also performed on 231 unique baseline isolates of Candida spp. from patients with invasive candidiasis. The majority (approximately 96%) of MICs were between 0.125 and 2 microg/ml, with MIC50 and MIC90 for caspofungin being 0.5 and 2.0 microg/ml, respectively. Overall, caspofungin demonstrated potent in vitro activity against clinical isolates of Candida species. A relationship between MIC for caspofungin and treatment outcome was not seen for patients with either esophageal candidiasis or invasive candidiasis. Patients with isolates for which the MICs were highest (>2 microg/ml) had better outcomes than patients with isolates for which the MICs were lower (<1 microg/ml). Additionally, no correlation between MIC and outcome was identified for specific Candida species.
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Affiliation(s)
- Nicholas Kartsonis
- Merck Research Laboratories, Merck & Co., Inc., BL 3-4, P.O. Box 4, West Point, PA 19486-0004, USA.
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Dabur R, Chhillar AK, Yadav V, Kamal PK, Gupta J, Sharma GL. In vitro antifungal activity of 2-(3,4-dimethyl-2,5-dihydro-1H-pyrrol-2-yl)-1-methylethyl pentanoate, a dihydropyrrole derivative. J Med Microbiol 2005; 54:549-552. [PMID: 15888463 DOI: 10.1099/jmm.0.45968-0] [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: 01/16/2023] Open
Abstract
A novel compound 2-(3,4-dimethyl-2,5-dihydro-1H-pyrrol-2-yl)-1-methylethyl pentanoate was isolated from the plant Datura metel L. The in vitro activity of this dihydropyrrole derivative against Aspergillus and Candida species was evaluated by using standard methods approved by the National Committee for Clinical Laboratory Standards. The compound was found to be active against all the species tested, namely Candida albicans, Candida tropicalis, Aspergillus fumigatus, Aspergillus flavus and Aspergillus niger. The MIC at which more than 90% of growth was inhibited (MIC(90)) by the compound ranged from 21.87 to 43.75 microg ml(-1) against various fungal species by microbroth dilution assay. Since the compound 2-(3,4-dimethyl-2,5-dihydro-1H-pyrrol-2-yl)-1-methylethyl pentanoate has antifungal activity it can be explored further to develop new antimycotic drugs.
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Affiliation(s)
- Rajesh Dabur
- Department of Biomedical Sciences, Bundelkhand University, Jhansi, India 2Institute of Genomics and Integrative Biology, Mall Road, Delhi, India
| | - A K Chhillar
- Department of Biomedical Sciences, Bundelkhand University, Jhansi, India 2Institute of Genomics and Integrative Biology, Mall Road, Delhi, India
| | - V Yadav
- Department of Biomedical Sciences, Bundelkhand University, Jhansi, India 2Institute of Genomics and Integrative Biology, Mall Road, Delhi, India
| | - Pradeep K Kamal
- Department of Biomedical Sciences, Bundelkhand University, Jhansi, India 2Institute of Genomics and Integrative Biology, Mall Road, Delhi, India
| | - J Gupta
- Department of Biomedical Sciences, Bundelkhand University, Jhansi, India 2Institute of Genomics and Integrative Biology, Mall Road, Delhi, India
| | - G L Sharma
- Department of Biomedical Sciences, Bundelkhand University, Jhansi, India 2Institute of Genomics and Integrative Biology, Mall Road, Delhi, India
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Mukherjee PK, Sheehan DJ, Hitchcock CA, Ghannoum MA. Combination treatment of invasive fungal infections. Clin Microbiol Rev 2005; 18:163-94. [PMID: 15653825 PMCID: PMC544182 DOI: 10.1128/cmr.18.1.163-194.2005] [Citation(s) in RCA: 209] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The persistence of high morbidity and mortality from systemic fungal infections despite the availability of novel antifungals points to the need for effective treatment strategies. Treatment of invasive fungal infections is often hampered by drug toxicity, tolerability, and specificity issues, and added complications often arise due to the lack of diagnostic tests and to treatment complexities. Combination therapy has been suggested as a possible approach to improve treatment outcome. In this article, we undertake a historical review of studies of combination therapy and also focus on recent studies involving newly approved antifungal agents. The limitations surrounding antifungal combinations include nonuniform interpretation criteria, inability to predict the likelihood of clinical success, strain variability, and variations in pharmacodynamic/pharmacokinetic properties of antifungals used in combination. The issue of antagonism between polyenes and azoles is beginning to be addressed, but data regarding other drug combinations are not adequate for us to draw definite conclusions. However, recent data have identified potentially useful combinations. Standardization of assay methods and adoption of common interpretive criteria are essential to avoid discrepancies between different in vitro studies. Larger clinical trials are needed to assess whether combination therapy improves survival and treatment outcome in the most seriously debilitated patients afflicted with life-threatening fungal infections.
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Affiliation(s)
- Pranab K Mukherjee
- Center for Medical Mycology, Department of Dermatology, Case Western Reserve University and University Hospitals of Cleveland, 11100 Euclid Ave., LKS-5028, Cleveland, OH 44106-5028, USA
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Cavalheiro RA, Fortes F, Borecký J, Faustinoni VC, Schreiber AZ, Vercesi AE. Respiration, oxidative phosphorylation, and uncoupling protein in Candida albicans. Braz J Med Biol Res 2004; 37:1455-61. [PMID: 15448865 DOI: 10.1590/s0100-879x2004001000003] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The respiration, membrane potential (Deltapsi), and oxidative phosphorylation of mitochondria in situ were determined in spheroplasts obtained from Candida albicans control strain ATCC 90028 by lyticase treatment. Mitochondria in situ were able to phosphorylate externally added ADP (200 microM) in the presence of 0.05% BSA. Mitochondria in situ generated and sustained stable mitochondrial Deltapsi respiring on 5 mM NAD-linked substrates, 5 mM succinate, or 100 microM N,N,N',N'-tetramethyl-p-phenylenediamine dihydrochloride plus 1 mM ascorbate. Rotenone (4 microM) inhibited respiration by 30% and 2 micro M antimycin A or myxothiazole and 1 mM cyanide inhibited it by 85%. Cyanide-insensitive respiration was partially blocked by 2 mM benzohydroxamic acid, suggesting the presence of an alternative oxidase. Candida albicans mitochondria in situ presented a carboxyatractyloside-insensitive increase of Deltapsi induced by 5 mM ATP and 0.5% BSA, and Deltapsi decrease induced by 10 microM linoleic acid, both suggesting the existence of an uncoupling protein. The presence of this protein was subsequently confirmed by immunodetection and respiration experiments with isolated mitochondria. In conclusion, Candida albicans ATCC 90028 possesses an alternative electron transfer chain and alternative oxidase, both absent in animal cells. These pathways can be exceptional targets for the design of new chemotherapeutic agents. Blockage of these respiratory pathways together with inhibition of the uncoupling protein (another potential target for drug design) could lead to increased production of reactive oxygen species, dysfunction of Candida mitochondria, and possibly to oxidative cell death.
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Affiliation(s)
- R A Cavalheiro
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, 13083-970 Campinas, SP, Brazil
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Abstract
Many variables affect the outcome of keratomycosis and systemic fungal infections in animals. These include pathogenicity of the fungal organism(toxins, trophisms, and evasion of host response); previous treatment with topical or systemic corticosteroids, which can have a dramatic negative impact on host defense mechanisms: concurrent systemic illness or immunocompromise: severity/extent of infection; and degree of pain (ie,increased reflex tearing dilutes topical medication) [14]. Experimental work suggests that antibiotics may occasionally exacerbate fungal infections [142],and some researchers advocate that concurrent antibiotic therapy is contraindicated in horses with yeast infections and septate fungal infections unless bacterial infection is also suspected [14]. Nevertheless, given that normal conjunctival flora often include bacteria and fungi and because care of keratomycoses often includes mixed bacterial and fungal infections, the possible dynamics (natural influences and local competition) between ocular surface microorganisms merit further investigation. There are many unanswered questions regarding the accuracy of in vitro susceptibilities and corneal concentration capabilities for antifungal topical medications [14]. Inherent host resistance or other immune interactions between the patient and fungus are perhaps the most important determinants of the outcome but are currently difficult to measure or assess except by subjective clinical observation [14].
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Affiliation(s)
- Marnie M Ford
- Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, 379 East Campus Drive, Columbia, MO 65211, USA.
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Hospenthal DR, Murray CK, Rinaldi MG. The role of antifungal susceptibility testing in the therapy of candidiasis. Diagn Microbiol Infect Dis 2004; 48:153-60. [PMID: 15023422 DOI: 10.1016/j.diagmicrobio.2003.10.003] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2003] [Accepted: 09/23/2003] [Indexed: 11/19/2022]
Abstract
Prior to the introduction of azoles, no real need for antifungal susceptibility testing (AFST) existed, as amphotericin B was the only agent available to treat systemic candidiasis. Introduction of fluconazole and itraconazole provided alternate, less toxic antifungal therapies. Intrinsic resistance of Candida krusei, decreased susceptibility of Candida glabrata, and development of resistance by Candida albicans (in mucosal disease in AIDS) to azoles led to development of our current AFST methodologies. The goal of AFST, like that of antibacterial susceptibility testing, is to predict clinical response, or at least to forecast failure. Although the ability of AFST to predict clinical outcome (clinical correlation) is still being fully elucidated, current methodologies do appear to reliably predict clinical resistance to azoles. Ready access to AFST is currently limited, affecting its timely use, but even with this lack of timeliness, AFST can still play an important role in patient care. Important potential roles include: 1) use in the development of local antibiograms to aid empiric selection of antifungals; 2) testing of isolates from candidemia or deep infection to aid in selection of long-term therapies; and, 3) the testing of isolates from recurrent mucosal disease to aid in selection of alternative regimens.
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Affiliation(s)
- Duane R Hospenthal
- Infectious Disease Service, Department of Medicine, Brooke Army Medical Center, Fort Sam Houston, TX 78234-6200, USA.
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