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Yoo K, Oliveira NK, Bhattacharya S, Fries BC. Achieving Resilience in Aging: How Mitochondrial Modulation Drives Age-associated Fluconazole Tolerance in Cryptococcus neoformans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.26.586817. [PMID: 38585804 PMCID: PMC10996610 DOI: 10.1101/2024.03.26.586817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Cryptococcus neoformans ( Cn ) is an opportunistic fungal microorganism that causes life-threatening meningoencephalitis. During the infection, the microbial population is heterogeneously composed of cells with varying generational ages, with older cells accumulating during chronic infections. This is attributed to their enhanced resistance to phagocytic killing and tolerance of antifungals like fluconazole (FLC). In this study, we investigated the role of ergosterol synthesis, ATP-binding cassette (ABC) transporters, and mitochondrial metabolism in the regulation of age-dependent FLC tolerance. We find that old Cn cells increase the production of ergosterol and exhibit upregulation of ABC transporters. Old cells also show transcriptional and phenotypic characteristics consistent with increased metabolic activity, leading to increased ATP production. This is accompanied by increased production of reactive oxygen species (ROS), which results in mitochondrial fragmentation. This study demonstrates that the metabolic changes occurring in the mitochondria of old cells drive the increase in ergosterol synthesis and the upregulation of ABC transporters, leading to FLC tolerance. IMPORTANCE Infections caused by Cryptococcus neoformans cause more than 180,000 deaths annually. Estimated one-year mortality for patients receiving care ranges from 20% in developed countries to 70% in developing countries, suggesting that current treatments are inadequate. Some fungal cells can persist and replicate despite the usage of current antifungal regimens, leading to death or treatment failure. In replicative aging, older cells display a resilient phenotype, characterized by their enhanced tolerance against antifungals and resistance to killing by host cells. This study shows that age-dependent increase in mitochondrial reactive oxygen species drive changes in ABC transporters and ergosterol synthesis, ultimately leading to the heightened tolerance against fluconazole in old C. neoformans cells. Understanding the underlying molecular mechanisms of this age-associated antifungal tolerance will enable more targeted antifungal therapies for cryptococcal infections.
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Chen L, Tian X, Zhang L, Wang W, Hu P, Ma Z, Li Y, Li S, Shen Z, Fan X, Ye L, Ke W, Wu Y, Shui G, Xiao M, He GJ, Yang Y, Fang W, Bai F, Liao G, Chen M, Lin X, Li C, Wang L. Brain glucose induces tolerance of Cryptococcus neoformans to amphotericin B during meningitis. Nat Microbiol 2024; 9:346-358. [PMID: 38225460 DOI: 10.1038/s41564-023-01561-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 11/15/2023] [Indexed: 01/17/2024]
Abstract
Antibiotic tolerance is the ability of a susceptible population to survive high doses of cidal drugs and has been shown to compromise therapeutic outcomes in bacterial infections. In comparison, whether fungicide tolerance can be induced by host-derived factors during fungal diseases remains largely unknown. Here, through a systematic evaluation of metabolite-drug-fungal interactions in the leading fungal meningitis pathogen, Cryptococcus neoformans, we found that brain glucose induces fungal tolerance to amphotericin B (AmB) in mouse brain tissue and patient cerebrospinal fluid via the fungal glucose repression activator Mig1. Mig1-mediated tolerance limits treatment efficacy for cryptococcal meningitis in mice via inhibiting the synthesis of ergosterol, the target of AmB, and promoting the production of inositolphosphorylceramide, which competes with AmB for ergosterol. Furthermore, AmB combined with an inhibitor of fungal-specific inositolphosphorylceramide synthase, aureobasidin A, shows better efficacy against cryptococcal meningitis in mice than do clinically recommended therapies.
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Affiliation(s)
- Lei Chen
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Xiuyun Tian
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Lanyue Zhang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Wenzhao Wang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Pengjie Hu
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Zhongyi Ma
- Medical Research Institute, College of Pharmaceutical Sciences, Southwest University, Chongqing, China
| | - Yeqi Li
- Department of Microbiology, University of Georgia, Athens, GA, USA
| | - Shibin Li
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Zhenghao Shen
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xin Fan
- Department of Infectious Diseases and Clinical Microbiology, Beijing Institute of Respiratory Medicine and Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China
| | - Leixin Ye
- Medical Research Institute, College of Pharmaceutical Sciences, Southwest University, Chongqing, China
| | - Weixin Ke
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yao Wu
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Guanghou Shui
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Meng Xiao
- Department of Clinical Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
- Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, China
| | - Guang-Jun He
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Ying Yang
- Beijing Key Laboratory of New Molecular Diagnosis Technologies for Infectious Disease, Department of Biotechnology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Wenxia Fang
- Institute of Biological Science and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
| | - Fan Bai
- Biomedical Pioneering Innovation Center (BIOPIC), School of Life Sciences, Peking University, Beijing, China
| | - Guojian Liao
- Medical Research Institute, College of Pharmaceutical Sciences, Southwest University, Chongqing, China
| | - Min Chen
- Department of Dermatology, Shanghai Key Laboratory of Medical Mycology, Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Xiaorong Lin
- Department of Microbiology, University of Georgia, Athens, GA, USA
| | - Chong Li
- Medical Research Institute, College of Pharmaceutical Sciences, Southwest University, Chongqing, China
| | - Linqi Wang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
- University of Chinese Academy of Sciences, Beijing, China.
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Chen L, Zhang L, Xie Y, Wang Y, Tian X, Fang W, Xue X, Wang L. Confronting antifungal resistance, tolerance, and persistence: Advances in drug target discovery and delivery systems. Adv Drug Deliv Rev 2023; 200:115007. [PMID: 37437715 DOI: 10.1016/j.addr.2023.115007] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 07/01/2023] [Accepted: 07/06/2023] [Indexed: 07/14/2023]
Abstract
Human pathogenic fungi pose a serious threat to human health and safety. Unfortunately, the limited number of antifungal options is exacerbated by the continuous emergence of drug-resistant variants, leading to frequent drug treatment failures. Recent studies have also highlighted the clinical importance of other modes of fungal survival of antifungal treatment, including drug tolerance and persistence, pointing to the complexity of the fungal response to antifungal drugs. A lack of understanding of the fungal drug response has hampered the identification of new targets, the development of alternative antifungal strategies and the design of appropriate delivery systems. In this review we summarize recent advances in the study of antifungal resistance, tolerance and persistence, with an emphasis on promising drug targets and drug delivery systems that may yield important insights into the development of new or improved antifungal therapies against fungal infections.
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Affiliation(s)
- Lei Chen
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Lanyue Zhang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Yuyan Xie
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Yiting Wang
- College of Life Sciences, Hebei University, Baoding, Hebei 071002, China
| | - Xiuyun Tian
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Wenxia Fang
- Institute of Biological Science and Technology, Guangxi Academy of Sciences, Nanning, 530007, Guangxi, China
| | - Xinying Xue
- Department of Respiratory and Critical Care, Beijing Shijitan Hospital, Capital Medical University; Peking University Ninth School of Clinical Medicine, Beijing 100038, China; Department of Respiratory and Critical Care, Weifang Medical College, 261053, Weifang, Shandong, China.
| | - Linqi Wang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China.
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4
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Zhao Y, Ye L, Zhao F, Zhang L, Lu Z, Chu T, Wang S, Liu Z, Sun Y, Chen M, Liao G, Ding C, Xu Y, Liao W, Wang L. Cryptococcus neoformans, a global threat to human health. Infect Dis Poverty 2023; 12:20. [PMID: 36932414 PMCID: PMC10020775 DOI: 10.1186/s40249-023-01073-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 02/27/2023] [Indexed: 03/18/2023] Open
Abstract
BACKGROUND Emerging fungal pathogens pose important threats to global public health. The World Health Organization has responded to the rising threat of traditionally neglected fungal infections by developing a Fungal Priority Pathogens List (FPPL). Taking the highest-ranked fungal pathogen in the FPPL, Cryptococcus neoformans, as a paradigm, we review progress made over the past two decades on its global burden, its clinical manifestation and management of cryptococcal infection, and its antifungal resistance. The purpose of this review is to drive research efforts to improve future diagnoses, therapies, and interventions associated with fungal infections. METHODS We first reviewed trends in the global burden of HIV-associated cryptococcal infection, mainly based on a series of systematic studies. We next conducted scoping reviews in accordance with the guidelines described in the Preferred Reporting Items for Systematic Reviews and Meta-analyses extension for Scoping Reviews using PubMed and ScienceDirect with the keyword Cryptococcus neoformans to identify case reports of cryptococcal infections published since 2000. We then reviewed recent updates on the diagnosis and antifungal treatment of cryptococcal infections. Finally, we summarized knowledge regarding the resistance and tolerance of C. neoformans to approved antifungal drugs. RESULTS There has been a general reduction in the estimated global burden of HIV-associated cryptococcal meningitis since 2009, probably due to improvements in highly active antiretroviral therapies. However, cryptococcal meningitis still accounts for 19% of AIDS-related deaths annually. The incidences of CM in Europe and North America and the Latin America region have increased by approximately two-fold since 2009, while other regions showed either reduced or stable numbers of cases. Unfortunately, diagnostic and treatment options for cryptococcal infections are limited, and emerging antifungal resistance exacerbates the public health burden. CONCLUSION The rising threat of C. neoformans is compounded by accumulating evidence for its ability to infect immunocompetent individuals and the emergence of antifungal-resistant variants. Emphasis should be placed on further understanding the mechanisms of pathogenicity and of antifungal resistance and tolerance. The development of novel management strategies through the identification of new drug targets and the discovery and optimization of new and existing diagnostics and therapeutics are key to reducing the health burden.
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Affiliation(s)
- Youbao Zhao
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, Henan, China.
| | - Leixin Ye
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100039, China
| | - Fujie Zhao
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, Henan, China
| | - Lanyue Zhang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100039, China
| | - Zhenguo Lu
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, Henan, China
| | - Tianxin Chu
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, Henan, China
| | - Siyu Wang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, Henan, China
| | - Zhanxiang Liu
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, Henan, China
| | - Yukai Sun
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, Henan, China
| | - Min Chen
- Department of Dermatology, Shanghai Key Laboratory of Molecular Medical Mycology, Changzheng Hospital, Shanghai, 200003, China
| | - Guojian Liao
- The Medical Research Institute, College of Pharmaceutical Sciences, Southwest University, Chongqing, 400715, China
| | - Chen Ding
- College of Life and Health Sciences, Northeastern University, Shenyang, 110819, Liaoning, China
| | - Yingchun Xu
- Department of Laboratory Medicine, and Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, 100730, China
| | - Wanqing Liao
- Department of Dermatology, Shanghai Key Laboratory of Molecular Medical Mycology, Changzheng Hospital, Shanghai, 200003, China
| | - Linqi Wang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
- University of Chinese Academy of Sciences, Beijing, 100039, China.
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Levorato-Vinche AD, Melhem MDSC, Bonfietti LX, de-la-Cruz-Chacón I, Boaro CSF, Fabro AT, Ferreira G, da Silva JDF, Dos Santos DC, Pereira BAS, Marçon C, Maza L, de Carvalho LR, Mendes RP. Antifungal activity of liriodenine on clinical strains of Cryptococcus neoformans and Cryptococcus gattii species complexes. J Venom Anim Toxins Incl Trop Dis 2022; 28:e20220006. [PMID: 36118844 PMCID: PMC9469771 DOI: 10.1590/1678-9199-jvatitd-2022-0006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 07/27/2022] [Indexed: 11/22/2022] Open
Abstract
Background: Cryptoccocal meningitis continues to present high incidence among AIDS patients. The treatment of choice is the synergistic combination of flucytosine (5-FC) with amphotericin B deoxycholate (AmBd) or its lipid formulations. However, 5-FC is unavailable in many countries and AmB demands hospitalization. The combination of AmB with the fungistatic fluconazole (FLC) or the use of high FLC daily doses alone became the choice. Nonetheless, sterilization of cerebrospinal fluid is delayed with FLC monotherapy, mainly with high fungal burden. These findings suggest the search for new antifungal compounds, such as liriodenine. Methods: Liriodenine antifungal activity was evaluated by three procedures: determining the minimum inhibitory concentration (MIC) on 30 strains of the Cryptococcus neoformans (C. neoformans) complex and 30 of the Cryptococcus gattii (C. gattii) complex, using EUCAST methodology and amphotericin B deoxycholate as control; performing the time-kill methodology in two strains of the C. neoformans complex and one of the C. gattii complex; and injury to cryptococcal cells, evaluated by transmission electron microscopy (TEM). Liriodenine absorption and safety at 0.75 and 1.50 mg.kg-1 doses were evaluated in BALB/c mice. Results: Liriodenine MICs ranged from 3.9 to 62.5 μg.mL-1 for both species complexes, with no differences between them. Time-kill methodology confirmed its concentration-dependent fungicidal effect, killing all the strains below the limit of detection (33 CFU.mL-1) at the highest liriodenine concentration (32-fold MIC), with predominant activity during the first 48 hours. Liriodenine induced severe Cryptococcus alterations - cytoplasm with intense rarefaction and/or degradation, injury of organelles, and presence of vacuoles. Liriodenine was better absorbed at lower doses, with no histopathological alterations on the digestive tract. Conclusion: The fungicidal activity confirmed by time-kill methodology, the intense Cryptococcus injury observed by TEM, the absorption after gavage administration, and the safety at the tested doses indicate that the liriodenine molecule is a promising drug lead for development of anticryptococcal agents.
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Affiliation(s)
- Adriele Dandara Levorato-Vinche
- Department of Infectology, Dermatology, Diagnostic Imaging and Radiotherapy, Botucatu Medical School (FMB), São Paulo State University (UNESP), Botucatu, SP, Brazil
| | - Marcia de Souza Carvalho Melhem
- Mycology Unit, Adolfo Lutz Institute, Public Health Reference Laboratory, Secretariat of Health of the State of São Paulo, São Paulo, SP, Brazil.,Medical School, Federal University of Mato Grosso do Sul, Campo Grande, MS, Brazil
| | - Lucas Xavier Bonfietti
- Mycology Unit, Adolfo Lutz Institute, Public Health Reference Laboratory, Secretariat of Health of the State of São Paulo, São Paulo, SP, Brazil
| | - Iván de-la-Cruz-Chacón
- Instituto de Ciencias Biológicas, Universidad de Ciencias y Artes de Chiapas, Tuxtla Gutierrez, Chiapas, Mexico
| | - Carmen Sílvia Fernandes Boaro
- Department of Biostatistics, Plant Biology, Parasitology and Zoology, Botucatu Biosciences Institute, São Paulo State University (UNESP), Botucatu, SP, Brazil
| | - Alexandre Todorovic Fabro
- Department of Pathology and Legal Medicine, Ribeirão Preto Medical School, University of São Paulo (USP), Ribeirão Preto, SP, Brazil
| | - Gisela Ferreira
- Department of Biostatistics, Plant Biology, Parasitology and Zoology, Botucatu Biosciences Institute, São Paulo State University (UNESP), Botucatu, SP, Brazil
| | - Julhiany de Fátima da Silva
- Department of Infectology, Dermatology, Diagnostic Imaging and Radiotherapy, Botucatu Medical School (FMB), São Paulo State University (UNESP), Botucatu, SP, Brazil
| | - Daniela Carvalho Dos Santos
- Department of Structural and Functional Biology, Botucatu Biosciences Institute, São Paulo State University (UNESP), Botucatu, SP, Brazil
| | - Beatriz Aparecida Soares Pereira
- Department of Infectology, Dermatology, Diagnostic Imaging and Radiotherapy, Botucatu Medical School (FMB), São Paulo State University (UNESP), Botucatu, SP, Brazil
| | - Camila Marçon
- Department of Infectology, Dermatology, Diagnostic Imaging and Radiotherapy, Botucatu Medical School (FMB), São Paulo State University (UNESP), Botucatu, SP, Brazil
| | - Lariza Maza
- Department of Infectology, Dermatology, Diagnostic Imaging and Radiotherapy, Botucatu Medical School (FMB), São Paulo State University (UNESP), Botucatu, SP, Brazil
| | - Lídia Raquel de Carvalho
- Department of Biostatistics, Plant Biology, Parasitology and Zoology, Botucatu Biosciences Institute, São Paulo State University (UNESP), Botucatu, SP, Brazil
| | - Rinaldo Poncio Mendes
- Department of Infectology, Dermatology, Diagnostic Imaging and Radiotherapy, Botucatu Medical School (FMB), São Paulo State University (UNESP), Botucatu, SP, Brazil
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6
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de Oliveira L, Melhem MDSC, Buccheri R, Chagas OJ, Vidal JE, Diaz-Quijano FA. Early clinical and microbiological predictors of outcome in hospitalized patients with cryptococcal meningitis. BMC Infect Dis 2022; 22:138. [PMID: 35139801 PMCID: PMC8830130 DOI: 10.1186/s12879-022-07118-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 01/20/2022] [Indexed: 11/10/2022] Open
Abstract
Background Cryptococcal meningitis causes high mortality in immunocompromised and immunocompetent patients. The objective of this study was to identify early predictors of clinical outcome, available at the first days of hospitalization, in patients with cryptococcal meningitis in a tertiary center in Brazil. Methods Ninety-six cases of cryptococcal meningitis with clinical, epidemiological and laboratory data, and identification and antifungal susceptibility of the strains were analyzed. Quantitative CSF yeast counts were performed by direct microscopic exam with a Fuchs-Rosenthal cell counting chamber using an institutional protocol. Univariable and multiple analyses using logistic regression were performed to identify predictors, available at the beginning of hospitalization, of in-hospital mortality. Moreover, we performed a secondary analysis for a composite outcome defined by hospital mortality and intensive care unit transfer. Results The species and the antifungal susceptibility were not associated with the outcomes evaluated. The variables significantly associated with the mortality were age (OR = 1.08, 95% CI 1.02–1.15), the cerebrospinal fluid (CSF) yeasts count (OR = 1.65, 95% CI 1.20–2.27), systemic arterial hypertension (OR = 22.63, 95% CI 1.64–312.91) and neurological impairment identified by computed tomography (OR = 41.73, 95% CI 3.10–561.65). At the secondary analysis, CSF yeast count was also associated with the composite outcome, in addition to the culture of Cryptococcus spp. from bloodstream and cerebral toxoplasmosis. The associations were consistent with survival models evaluated. Conclusions Age and CSF yeast count were independently associated with in-hospital mortality of patients with cryptococcal meningitis but Cryptococcus species identification and antifungal susceptibility were not associated with the outcomes. Quantitative CSF yeast counts used in this study can be evaluated and implemented in other low and middle-income settings. Supplementary Information The online version contains supplementary material available at 10.1186/s12879-022-07118-7.
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Affiliation(s)
- Lidiane de Oliveira
- Department of Epidemiology, School of Public Health, University of São Paulo, Av. Dr. Arnaldo, 715, São Paulo, SP, CEP 01246-904, Brazil.
| | - Marcia de Souza Carvalho Melhem
- Mycology Unit of Adolfo Lutz Institute, Public Health Reference Laboratory, Secretary of Health, Av. Dr.Arnaldo, 351, São Paulo, SP, CEP 05411-000, Brazil.,School of Medicine, Federal University of Mato Grosso do Sul, Bairro Universitário, Av. Costa e Silva, s/no, Campo Grande, MS, CEP 79070-900, Brazil
| | - Renata Buccheri
- Department of Neurology, Emílio Ribas Institute of Infectious Diseases, Av. Dr. Arnaldo 165, São Paulo, SP, CEP 05411-000, Brazil
| | - Oscar José Chagas
- Department of Neurology, Emílio Ribas Institute of Infectious Diseases, Av. Dr. Arnaldo 165, São Paulo, SP, CEP 05411-000, Brazil
| | - José Ernesto Vidal
- Department of Neurology, Emílio Ribas Institute of Infectious Diseases, Av. Dr. Arnaldo 165, São Paulo, SP, CEP 05411-000, Brazil.,Department of Infectious Diseases, Hospital das Clinicas, School of Medicine, University of São Paulo, Av. Dr. Enéas de Carvalho Aguiar, 470, São Paulo, SP, CEP 01246-904, Brazil
| | - Fredi Alexander Diaz-Quijano
- Department of Epidemiology, School of Public Health, University of São Paulo, Av. Dr. Arnaldo, 715, São Paulo, SP, CEP 01246-904, Brazil
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7
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Spicer SK, Subramani A, Aguila AL, Green RM, McClelland EE, Bicker KL. Toward a clinical antifungal peptoid: Investigations into the therapeutic potential of AEC5. Biopolymers 2019; 110:e23276. [PMID: 30938841 PMCID: PMC6660985 DOI: 10.1002/bip.23276] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 03/13/2019] [Accepted: 03/18/2019] [Indexed: 01/08/2023]
Abstract
Cryptococcus neoformans is a fungal pathogen that causes cryptococcal meningitis in immunocompromised individuals. Existing antifungal treatment plans have high mammalian toxicity and increasing drug resistance, demonstrating the dire need for new, nontoxic therapeutics. Antimicrobial peptoids are one alternative to combat this issue. Our lab has recently identified a tripeptoid, AEC5, with promising efficacy and selectivity against C. neoformans. Here, we report studies into the broad-spectrum efficacy, killing kinetics, mechanism of action, in vivo half-life, and subchronic toxicity of this compound. Most notably, these studies have demonstrated that AEC5 rapidly reduces fungal burden, killing all viable fungi within 3 hours. Additionally, AEC5 has an in vivo half-life of 20+ hours and no observable in vivo toxicity following 28 days of daily injections. This research represents an important step in the characterization of AEC5 as a practical treatment option against C. neoformans infections.
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Affiliation(s)
- Sabrina K. Spicer
- Middle Tennessee State University, Department of Chemistry, 1301 E. Main St., Murfreesboro, TN 37132
| | - Aarthi Subramani
- Middle Tennessee State University, Department of Biology, 1301 E. Main St., Murfreesboro, TN 37132
| | - Angelica L. Aguila
- Middle Tennessee State University, Department of Chemistry, 1301 E. Main St., Murfreesboro, TN 37132
| | - R. Madison Green
- Middle Tennessee State University, Department of Chemistry, 1301 E. Main St., Murfreesboro, TN 37132
| | - Erin E. McClelland
- Middle Tennessee State University, Department of Biology, 1301 E. Main St., Murfreesboro, TN 37132
| | - Kevin L. Bicker
- Middle Tennessee State University, Department of Chemistry, 1301 E. Main St., Murfreesboro, TN 37132
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8
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de Oliveira L, Cristina Silva Santos D, dos Anjos Martins M, Szeszs MW, Souza Carvalho Melhem M. Time-Kill Curves Studies with Amphotericin B Against Cryptococcus neoformans/C. gattii Species Complex Clinical Isolates. CURRENT FUNGAL INFECTION REPORTS 2017. [DOI: 10.1007/s12281-017-0296-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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9
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Comparison of Different In Vitro Tests to Detect Cryptococcus neoformans Not Susceptible to Amphotericin B. Mycopathologia 2015; 179:359-71. [DOI: 10.1007/s11046-015-9871-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 02/03/2015] [Indexed: 01/05/2023]
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10
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Silva DC, Martins MA, Szeszs MW, Bonfietti LX, Matos D, Melhem MSC. Susceptibility to antifungal agents and genotypes of Brazilian clinical and environmental Cryptococcus gattii strains. Diagn Microbiol Infect Dis 2012; 72:332-9. [PMID: 22341512 DOI: 10.1016/j.diagmicrobio.2011.11.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Revised: 11/21/2011] [Accepted: 11/23/2011] [Indexed: 11/26/2022]
Abstract
There are few reports concerning the in vitro antifungal susceptibility of clinical and environmental Cryptococcus gattii isolates. In this study, we performed polymerase chain reaction-restriction fragment length polymorphism to investigate the molecular subtypes of 50 clinical and 4 environmental Brazilian isolates of C. gattii and assessed their antifungal susceptibility for fluconazole (FLU) and amphotericin B (Amb) according to recent recommendations proposed for antifungal susceptibility testing of nonfermentative yeasts. Time-kill curve studies were performed using RPMI 1640 medium to analyze the fungicidal effect of AmB. We found 47 VGII (94%) molecular types and 3 VGI (6%) types among the clinical isolates. The environmental isolates were VGII (75%) subtype and VGI (25%) subtype. The FLU-MIC ranged from 1 to 64 mg L(-1), and MIC(50)/MIC(90) values were, respectively, 8/16 mg L(-1). For AmB, the MICs were low and homogeneous, ranging from 0.12 to 0.5 mg L(-1), for VGI or VGII. The time required to reach the fungicidal end point (99.9% killing) was 6 h for the majority of strains (64%), but viable cells of VGII were still present after 48 h of exposition. We pointed out the occurrence of high FLU-MICs for C. gattii isolates with highest values for VGII. Our data also suggest that the rate of killing of C. gattii by AmB is strain dependent, and viable cells of VGII genotype strains were still observed after an extended incubation time, addressing future studies to determine whether the in vitro fungicidal activity could be clinically relevant.
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Affiliation(s)
- Dayane C Silva
- Mycology Unit of Adolfo Lutz Institute, Public Health Reference Laboratory, Secretary of Health, São Paulo-SP, 01246-902, Brazil
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Córdoba S, Afeltra J, Vitale RG. Evaluation of the in vitro activity of amphotericin B by time-kill curve methodology against large and small capsulate C. neoformans isolates. Diagn Microbiol Infect Dis 2011; 71:260-2. [PMID: 21917396 DOI: 10.1016/j.diagmicrobio.2011.08.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 07/31/2011] [Accepted: 08/02/2011] [Indexed: 11/18/2022]
Abstract
We have evaluated and compared the activity of amphotericin B (AMB) by time-kill curve methodology against 20 clinical Cryptococcus neoformans isolates in which capsule induction in vitro was performed. Overall, large capsulated isolates were more resistant to killing by AMB over time when compared with those small capsulate ones.
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Affiliation(s)
- Susana Córdoba
- Departamento de Micologia; Instituto Nacional de Enfermedades Infecciosas, (INEI), ANLIS Dr. C.G. Malbrán, Buenos Aires 1281, Argentina
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12
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Arechavala AI, Ochiuzzi ME, Borgnia MD, Santiso GM. Fluconazole and amphotericin B susceptibility testing of Cryptococcus neoformans: Results of minimal inhibitory concentrations against 265 isolates from HIV-positive patients before and after two or more months of antifungal therapy. Rev Iberoam Micol 2009; 26:194-7. [DOI: 10.1016/j.riam.2009.02.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2008] [Accepted: 02/24/2009] [Indexed: 10/20/2022] Open
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13
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Pappalardo MC, Szeszs MW, Martins MA, Baceti LB, Bonfietti LX, Purisco SU, Baez AA, Melhem MS. Susceptibility of clinical isolates of Cryptococcus neoformans to amphotericin B using time–kill methodology. Diagn Microbiol Infect Dis 2009; 64:146-51. [DOI: 10.1016/j.diagmicrobio.2009.02.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2008] [Revised: 01/30/2009] [Accepted: 02/13/2009] [Indexed: 10/20/2022]
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14
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Alves SH, Boff E, Pozzatti P, Scheid LA, de Loreto E, Ottoneli Oliveira LT, Aquino V, Severo LC, Santurio JM. Relationship between susceptibility of Candida spp. isolates to amphotericin B and death or survival of patients with candidemia episodes. Mycopathologia 2008; 167:65-71. [PMID: 18819017 DOI: 10.1007/s11046-008-9159-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2008] [Accepted: 09/10/2008] [Indexed: 11/24/2022]
Abstract
In this study, the susceptibility to amphotericin B of Candida spp. isolates obtained from patients with candidemia was related to their respective clinical outcomes. The susceptibility tests were carried out in three culture media: RPMI 1640, Antibiotic medium 3 and Yeast Nitrogen Base dextrose. We have found that minimal inhibitory concentrations and minimal fungicidal concentrations obtained using AM3 and YNBd media were significantly higher for Candida spp. from patients who died than for those from patients who survived the candidemia (P < 0.05). The assays with RPMI 1640 medium did not show these differences.
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Affiliation(s)
- Sydney Hartz Alves
- Department of Microbiology and Parasitology, Universidade Federal de Santa Maria, Rua dos Andradas 1985/201, Santa Maria, RS, Brazil.
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15
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Dannaoui E, Abdul M, Arpin M, Michel-Nguyen A, Piens MA, Favel A, Lortholary O, Dromer F. Results obtained with various antifungal susceptibility testing methods do not predict early clinical outcome in patients with cryptococcosis. Antimicrob Agents Chemother 2006; 50:2464-70. [PMID: 16801427 PMCID: PMC1489793 DOI: 10.1128/aac.01520-05] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The in vitro susceptibilities of Cryptococcus neoformans isolates from consecutive human immunodeficiency virus-positive and -negative patients to the antifungal agents fluconazole, amphotericin B, and flucytosine were determined by different techniques, including the CLSI method, Etest, and broth microdilution in yeast nitrogen base (YNB) medium, during a multicenter prospective study in France. The relationship between the in vitro data and the clinical outcome 2 weeks after the initiation of antifungal therapy was assessed. In addition, the correlation between the strain serotype and the in vitro activities of the antifungals was determined, and the susceptibility results obtained with the different techniques were also compared. Thirty-seven patients received a combination of amphotericin B with flucytosine as first-line therapy, 22 were treated with amphotericin B alone, and 15 received fluconazole alone. Whatever the antifungal tested, there was no trend toward higher MICs for strains isolated from patients who failed to respond to a given therapy compared to those from patients who did not with either the CLSI method, Etest, or broth microdilution in YNB medium. The MICs obtained by the CLSI or Etest method were significantly lower for serotype D strains than for serotype A strains for both fluconazole and amphotericin B, while flucytosine MICs were not different according to serotype. These findings suggest that the in vitro antifungal susceptibility of C. neoformans, as determined with the techniques used, is not able to predict the early clinical outcome in patients with cryptococcosis.
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Affiliation(s)
- E Dannaoui
- Centre National de Référence Mycologie et Antifongiques, Unité de Mycologie Moléculaire, CNRS FRE2849, Institut Pasteur, 25, rue du Dr. Roux, 75724 Paris Cedex 15, France.
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16
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Abstract
Echinocandins are a novel class of antifungal drugs. They have good activity against Candida spp and Aspergillus spp. Their low selective toxicity allows their administration at high doses with few secondary side effects. We have reviewed the available data on the endpoints for these drugs in their in vitro susceptibility testing on yeasts and moulds. The microdilution broth method is the most commonly used technique and MIC-1 (80% of growth inhibition) seems to be the most reliable endpoint when yeasts are tested. This endpoint also seems to be the most appropriate for the different drugs when they are combined with echinocandins using the checkerboard method for testing yeasts. By contrast, in the case of moulds, the minimum effective concentration (MEC) correlates better with the in vivo activity than the MIC when echinocandins are tested, and when these drugs are combined with other antifungals, MIC-2 (50% of growth inhibition) seems the most appropriate endpoint. Criteria based on drug pharmacodynamics is the most useful to define the echinocandin endpoints that best correlate with their in vivo efficacy.
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Affiliation(s)
- Francisco Javier Pastor
- Unitat de Microbiologia, Facultat de Medicina i Ciencies de la Salut, Universitat Rovira i Virgili, Reus, Spain.
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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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18
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Cantón E, Pemán J, Gobernado M, Viudes A, Espinel-Ingroff A. Patterns of amphotericin B killing kinetics against seven Candida species. Antimicrob Agents Chemother 2004; 48:2477-82. [PMID: 15215097 PMCID: PMC434204 DOI: 10.1128/aac.48.7.2477-2482.2004] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In a previous study tolerance to amphotericin B (AMB) was found among Candida parapsilosis and C. dubliniensis strains by seeding the whole volumes of wells used for MIC determinations, and minimum fungicidal concentrations (MFC) for non-C. albicans Candida strains were demonstrated to be above the levels safely achievable in serum. As an extension of that study, we performed time-kill assays with 26 blood culture isolates (6 C. albicans, 5 C. parapsilosis, 5 C. krusei, 4 C. glabrata, 3 C. lusitaniae, and 3 C. tropicalis isolates), 3 oropharyngeal C. dubliniensis isolates, 3 AMB-susceptible isolates (ATCC 90028, ATCC 22019, ATCC 6254), and 6 AMB-resistant isolates (ATCC 200955, ATCC 200956, ATCC 200950, ATCC 200951, ATCC 200952, ATCC 200953) using RPMI 1640 medium and 0.12 to 32 microg of AMB per ml and determined the numbers of CFU per milliliter at 0, 2, 4, 8, 12, 24, and 48 h. MFCs and time-kill patterns were species specific (MFCs, < or =1 microg/ml for all C. dubliniensis and C. albicans isolates except AMB-resistant strain ATCC 200955; MFCs, 2 to >16 microg/ml for the other isolates). The times required to reach the fungicidal endpoint (99.9% killing) at four times the MIC were 2 h for C. albicans and C. dubliniensis, 16 h for C. glabrata, 24 h for C. parapsilosis and C. lusitaniae, and > or =40 h for C. tropicalis and C. krusei. The killing rate increased as the AMB concentration was increased up to 2 microg/ml. The highest killing rates were achieved for C. albicans, C. dubliniensis, and C. lusitaniae, while viable C. tropicalis, C. krusei, and C. parapsilosis cells were present after 48 h (MICs, < or =2 microg/ml) when AMB was used at 2 microg/ml. Time-kill curves and MFCs can detect viable cells after 48 h when AMB is used at > or =2 microg/ml. The failure of AMB treatment could be due to its poor killing activity against some species at the concentrations reached in patients' serum.
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Affiliation(s)
- Emilia Cantón
- Unidad de Microbiología Experimental, Centro de Investigación, Hospital Universitario La Fe, Avenida Campanar 21, 46009 Valencia, Spain.
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19
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Minimum fungicidal concentrations of amphotericin B for bloodstream Candida species. Diagn Microbiol Infect Dis 2003; 45:203-6. [PMID: 12663162 DOI: 10.1016/s0732-8893(02)00525-4] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Minimum fungicidal concentrations (MFCs) of amphotericin B were obtained for 165 bloodstream isolates (104 Candida parapsilosis, 14 C.glabrata, 13 C.tropicalis, 15 C.krusei, and 19 C.albicans) and 36 C.dubliniensis from oropharyngeal infections. Minimum inhibitory concentrations (MICs) were determined by the M27-A microdilution method. MFCs (> or =99.9% killing) were obtained following MIC determination (inoculum size, 10(4) CFU/ml) by seeding the entire volume of all clear wells. The best fungicidal activity was for C. albicans, (MFC90 1 microg/ml) and the lowest for C.parapsilosis, C.tropicalis and C.glabrata (MFC90 16 microg/ml). Although MFCs were > or =16x MIC for some isolates, including C. glabrata, the overall MFCs were > or =2x MICs. However, major differences between MICs and MFCs were observed for C.parapsilosis and C.dubliniensis (3.8% and 8.9%, respectively, were tolerant: MFC > or =32MIC). MFCs for C.tropicalis and C. glabrata were > or =2 microg/ml. By this more stringent method we found substantial differences from those previously reported between amphotericin B MIC and MFCs for Candida spp.
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20
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Rex JH, Pfaller MA. Has antifungal susceptibility testing come of age? Clin Infect Dis 2002; 35:982-9. [PMID: 12355386 DOI: 10.1086/342384] [Citation(s) in RCA: 234] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2002] [Revised: 04/10/2002] [Indexed: 11/03/2022] Open
Abstract
The in vitro susceptibility of an infecting organism to the antimicrobial agent selected for therapy is one of several factors that influence the likelihood that therapy for an infection will be successful. To appreciate the value of antifungal susceptibility testing, it is helpful to review the overall predictive utility of antibacterial susceptibility testing. After >30 years of study, in vitro susceptibility can be said to predict the response of bacterial infections with an accuracy that is well summarized as the "90-60 rule": infections due to susceptible isolates respond to therapy approximately 90% of the time, whereas infections due to resistant isolates respond approximately 60% of the time. On the basis of a growing body of knowledge, standardized susceptibility testing for selected organism-drug combinations (most notably, Candida species and the azole antifungal agents) has been shown to have similar predictive utility. Antifungal susceptibility testing is now increasingly and appropriately used as a routine adjunct to the treatment of fungal infections.
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Affiliation(s)
- John H Rex
- Division of Infectious Diseases, Department of Internal Medicine, Center for the Study of Emerging and Reemerging Pathogens, University of TexasHouston Medical School, Houston 77030, USA.
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Toriumi Y, Sugita T, Nakajima M, Matsushima T, Shinoda T. Antifungal pharmacodynamic characteristics of amphotericin B against Trichosporon asahii, using time-kill methodology. Microbiol Immunol 2002; 46:89-93. [PMID: 11939583 DOI: 10.1111/j.1348-0421.2002.tb02663.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We determined the MIC of amphotericin B against 45 Trichosporon asahii isolates from various clinical and environmental sources, and used in vitro time-kill methods to characterize the relationship between amphotericin B concentrations and MIC for four representative T. asahii isolates. Amphotericin B had concentration-dependent antifungal activity. MICs ranged from 0.5 to 16 microg/ml, and most T. asahii isolates (76%, 34/45) were inhibited at safely achievable amphotericin B serum concentrations (< or = 2 microg/ml). However, 40% (18/45) of isolates were not killed at these concentrations (MFCs from 1.0 to 32 microg/ml). At concentrations > or = 2 x MIC, amphotericin B exhibited fungicidal activity (< 99.9% reduction in CFU) over a 12-hr time-period; the maximal effect was achieved at > or =4 x MIC. Susceptibility testing confirmed the resistance of T. asahii to amphotericin B, and in vitro pharmacodynamic results also suggest that amphotericin B is not suitable therapy for T. asahii infection.
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Affiliation(s)
- Yoshimi Toriumi
- Department of Microbiology, Meiji Pharmaceutical University, Kiyose, Tokyo, Japan
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22
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Rodero L, Cuenca-Estrella M, Córdoba S, Cahn P, Davel G, Kaufman S, Guelfand L, Rodríguez-Tudela JL. Transient fungemia caused by an amphotericin B-resistant isolate of Candida haemulonii. J Clin Microbiol 2002; 40:2266-9. [PMID: 12037106 PMCID: PMC130759 DOI: 10.1128/jcm.40.6.2266-2269.2002] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A bloodstream infection due to Candida haemulonii afflicting a patient with fever and a medical history of megaloblastic anemia is reported. The clinical isolate was misidentified by the API 20C and VITEK identification systems. The results of susceptibility tests showed that the MIC of amphotericin B for C. haemulonii was 4 microg/ml. Additional susceptibility testing procedures based on the use of antibiotic medium 3 and Iso-Sensitest broth were performed, and killing curves were determined. Two collection strains of C. haemulonii were employed as controls. The three isolates exhibited resistance to amphotericin B in vitro regardless of the antifungal susceptibility testing method employed. In addition, the MICs of fluconazole for the three isolates were high. Further studies are needed in order to ascertain whether this species exhibits innate or acquired resistance to amphotericin B and other antifungal agents.
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Affiliation(s)
- Laura Rodero
- Departamento Micología, INEI, ANLIS Dr. Carlos G. Malbrán, Hospital Fernández, Buenos Aires, Argentina.
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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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