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Melhem MSC, Leite Júnior DP, Takahashi JPF, Macioni MB, Oliveira LD, de Araújo LS, Fava WS, Bonfietti LX, Paniago AMM, Venturini J, Espinel-Ingroff A. Antifungal Resistance in Cryptococcal Infections. Pathogens 2024; 13:128. [PMID: 38392866 PMCID: PMC10891860 DOI: 10.3390/pathogens13020128] [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: 10/23/2023] [Revised: 01/20/2024] [Accepted: 01/22/2024] [Indexed: 02/25/2024] Open
Abstract
Antifungal therapy, especially with the azoles, could promote the incidence of less susceptible isolates of Cryptococcus neoformans and C. gattii species complexes (SC), mostly in developing countries. Given that these species affect mostly the immunocompromised host, the infections are severe and difficult to treat. This review encompasses the following topics: 1. infecting species and their virulence, 2. treatment, 3. antifungal susceptibility methods and available categorical endpoints, 4. genetic mechanisms of resistance, 5. clinical resistance, 6. fluconazole minimal inhibitory concentrations (MICs), clinical outcome, 7. environmental influences, and 8. the relevance of host factors, including pharmacokinetic/pharmacodynamic (PK/PD) parameters, in predicting the clinical outcome to therapy. As of now, epidemiologic cutoff endpoints (ECVs/ECOFFs) are the most reliable antifungal resistance detectors for these species, as only one clinical breakpoint (amphotericin B and C. neoformans VNI) is available.
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Affiliation(s)
- Marcia S C Melhem
- Graduate Program in Sciences, Secretary of Health, São Paulo 01246-002, SP, Brazil
- Graduate Program in Infectious and Parasitic Diseases, Federal University of Mato Grosso do Sul, Campo Grande 79070-900, MS, Brazil
- Graduate Program in Tropical Diseases, State University of São Paulo, Botucatu 18618-687, SP, Brazil
| | | | - Juliana P F Takahashi
- Graduate Program in Infectious and Parasitic Diseases, Federal University of Mato Grosso do Sul, Campo Grande 79070-900, MS, Brazil
- Pathology Division, Adolfo Lutz Institute, São Paulo 01246-002, SP, Brazil
| | | | | | - Lisandra Siufi de Araújo
- Graduate Program in Infectious and Parasitic Diseases, Federal University of Mato Grosso do Sul, Campo Grande 79070-900, MS, Brazil
- Central Public Health Laboratory-LACEN, Mycology Unit, Adolfo Lutz Institut, São Paulo 01246-002, SP, Brazil
| | - Wellington S Fava
- Graduate Program in Infectious and Parasitic Diseases, Federal University of Mato Grosso do Sul, Campo Grande 79070-900, MS, Brazil
| | - Lucas X Bonfietti
- Central Public Health Laboratory-LACEN, Mycology Unit, Adolfo Lutz Institut, São Paulo 01246-002, SP, Brazil
| | - Anamaria M M Paniago
- Graduate Program in Infectious and Parasitic Diseases, Federal University of Mato Grosso do Sul, Campo Grande 79070-900, MS, Brazil
| | - James Venturini
- Graduate Program in Infectious and Parasitic Diseases, Federal University of Mato Grosso do Sul, Campo Grande 79070-900, MS, Brazil
| | - Ana Espinel-Ingroff
- Central Public Health Laboratory-LACEN, Campo Grande 79074-460, MS, Brazil
- VCU Medical Center, Richmond, VA 23284, USA
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2
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McHale TC, Boulware DR, Kasibante J, Ssebambulidde K, Skipper CP, Abassi M. Diagnosis and management of cryptococcal meningitis in HIV-infected adults. Clin Microbiol Rev 2023; 36:e0015622. [PMID: 38014977 PMCID: PMC10870732 DOI: 10.1128/cmr.00156-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023] Open
Abstract
Cryptococcal meningitis is a leading cause of morbidity and mortality globally, especially in people with advanced HIV disease. Cryptococcal meningitis is responsible for nearly 20% of all deaths related to advanced HIV disease, with the burden of disease predominantly experienced by people in resource-limited countries. Major advancements in diagnostics have introduced low-cost, easy-to-use antigen tests with remarkably high sensitivity and specificity. These tests have led to improved diagnostic accuracy and are essential for screening campaigns to reduce the burden of cryptococcosis. In the last 5 years, several high-quality, multisite clinical trials have led to innovations in therapeutics that have allowed for simplified regimens, which are better tolerated and result in less intensive monitoring and management of medication adverse effects. One trial found that a shorter, 7-day course of deoxycholate amphotericin B is as effective as the longer 14-day course and that flucytosine is an essential partner drug for reducing mortality in the acute phase of disease. Single-dose liposomal amphotericin B has also been found to be as effective as a 7-day course of deoxycholate amphotericin B. These findings have allowed for simpler and safer treatment regimens that also reduce the burden on the healthcare system. This review provides a detailed discussion of the latest evidence guiding the clinical management and special circumstances that make cryptococcal meningitis uniquely difficult to treat.
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Affiliation(s)
- Thomas C. McHale
- Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - David R. Boulware
- Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - John Kasibante
- Infectious Diseases Institute, Makerere University, Kampala, Uganda
| | | | - Caleb P. Skipper
- Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Mahsa Abassi
- Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
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3
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Lin K, Lai Y, Lin Y, Ho M, Chen Y, Chung W. Antifungal Susceptibility of the Clinical and Environmental Strains of
Cryptococcus gattii sensu lato
in Taiwan. Mycoses 2022; 66:13-24. [DOI: 10.1111/myc.13520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 08/11/2022] [Accepted: 08/15/2022] [Indexed: 11/28/2022]
Affiliation(s)
- Kuo‐Hsi Lin
- Tungs’ Taichung MetroHarbor Hospital Taichung Taiwan
- National Chung Hsing University Taichung Taiwan
| | - Yi‐Chyi Lai
- Chung Shan Medical University Taichung Taiwan
| | - Yi‐Pei Lin
- Tungs’ Taichung MetroHarbor Hospital Taichung Taiwan
| | - Mao‐Wang Ho
- China Medical University Hospital Taichung Taiwan
| | | | - Wen‐Hsin Chung
- National Chung Hsing University Taichung Taiwan
- Innovation and Development center of sustainable Agriculture (IDCSA), Taichung Taiwan
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Gerlach ES, Altamirano S, Yoder JM, Luggya TS, Akampurira A, Meya DB, Boulware DR, Rhein J, Nielsen K. ATI-2307 Exhibits Equivalent Antifungal Activity in Cryptococcus neoformans Clinical Isolates With High and Low Fluconazole IC 50. Front Cell Infect Microbiol 2021; 11:695240. [PMID: 34249782 PMCID: PMC8262267 DOI: 10.3389/fcimb.2021.695240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 05/10/2021] [Indexed: 01/16/2023] Open
Abstract
Half maximal inhibitory concentrations (IC50) to the experimental drug ATI-2307 and complete inhibition (IC90) of the common clinically used antifungal drug amphotericin B were determined by microbroth dilution assay for a collection of 69 clinical isolates of Cryptococcus neoformans from Uganda that had high fluconazole IC50 values. The majority of the clinical isolates tested had fluconazole IC50 at or above 8 µg/mL, but were susceptible to both amphotericin B (IC90 ≤1 μg/mL) and ATI-2307 (IC50 ≤0.0312 µg/mL). No correlation between increased fluconazole minimum inhibitory concentration (MIC) and ATI-2307 or amphotericin B MIC was observed, suggesting that the cellular changes impacting fluconazole susceptibility did not impact the effectiveness of ATI-2307. Our results suggest that ATI-2307 is a promising new antifungal drug for use in the context of high fluconazole or other antifungal drug MICs and/or in combination drug therapy regimens.
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Affiliation(s)
- Elliot S. Gerlach
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, United States
| | - Sophie Altamirano
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, United States
| | - J. Marina Yoder
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, United States
| | - Tony S. Luggya
- Infectious Diseases Institute, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Andrew Akampurira
- Infectious Diseases Institute, College of Health Sciences, Makerere University, Kampala, Uganda
| | - David B. Meya
- Infectious Diseases Institute, College of Health Sciences, Makerere University, Kampala, Uganda
| | - David R. Boulware
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Joshua Rhein
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Kirsten Nielsen
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, United States
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5
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Chesdachai S, Rajasingham R, Nicol MR, Meya DB, Bongomin F, Abassi M, Skipper C, Kwizera R, Rhein J, Boulware DR. Minimum Inhibitory Concentration Distribution of Fluconazole against Cryptococcus Species and the Fluconazole Exposure Prediction Model. Open Forum Infect Dis 2019; 6:5550889. [PMID: 31420668 PMCID: PMC6767974 DOI: 10.1093/ofid/ofz369] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Fluconazole is lifesaving for treatment and prevention of cryptococcosis; however, optimal dosing is unknown. Initial fluconazole doses of 100mg to 2000mg/day have been used. Prevalence of fluconazole non-susceptible Cryptococcus is increasing over time, risking the efficacy of long-established standard dosing. Based on current minimum inhibitory concentration (MIC) distribution, we modeled fluconazole concentration and area under the curve (AUC) relative to MIC to propose a rational fluconazole dosing strategy. METHODS First, we conducted a systematic review using MEDLINE database for reports of fluconazole MIC distribution against clinical Cryptococcus isolates. Second, we utilized fluconazole concentrations from 92 Ugandans who received fluconazole 800mg/day coupled with fluconazole's known pharmacokinetics to predict plasma fluconazole concentrations for doses ranging from 100mg to 2000mg via linear regression. Third, the fluconazole AUC above MIC ratio were calculated using Monte Carlo simulation and using the MIC distribution elucidated during the systemic review. RESULTS We summarized 21 studies with 11,049 clinical Cryptococcus isolates. MICs were normally distributed with geometric mean of 3.4 μg/mL, median (MIC50) of 4 μg/mL, and 90th percentile (MIC90) of 16 μg/mL. The median MIC50 trended upwards from 4 μg/mL in 2000-2012 to 8 μg/mL in 2014-2018. Predicted sub-therapeutic fluconazole concentrations (below MIC) would occur in 40% with 100mg, 21% with 200mg, and 9% with 400mg. AUC/MIC ratio >100 would occur in 53% for 400mg, 74% for 800mg, 83% for 1200mg, and 88% for 1600mg. CONCLUSIONS Currently recommended fluconazole doses may be inadequate for cryptococcosis. Further clinical studies are needed for rational fluconazole dose selection.
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Affiliation(s)
| | - Radha Rajasingham
- Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Melanie R Nicol
- College of Pharmacy, Department of Experimental and Clinical Pharmacology, University of Minnesota, Minneapolis, MN, USA
| | - David B Meya
- Infectious Diseases Institute, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Felix Bongomin
- Department of Medical Microbiology and Immunology, Faculty of Medicine, Gulu University, Gulu, Uganda
| | - Mahsa Abassi
- Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Caleb Skipper
- Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Richard Kwizera
- Infectious Diseases Institute, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Joshua Rhein
- Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - David R Boulware
- Department of Medicine, University of Minnesota, Minneapolis, MN, USA
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6
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Naran K, Nundalall T, Chetty S, Barth S. Principles of Immunotherapy: Implications for Treatment Strategies in Cancer and Infectious Diseases. Front Microbiol 2018; 9:3158. [PMID: 30622524 PMCID: PMC6308495 DOI: 10.3389/fmicb.2018.03158] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 12/05/2018] [Indexed: 12/13/2022] Open
Abstract
The advances in cancer biology and pathogenesis during the past two decades, have resulted in immunotherapeutic strategies that have revolutionized the treatment of malignancies, from relatively non-selective toxic agents to specific, mechanism-based therapies. Despite extensive global efforts, infectious diseases remain a leading cause of morbidity and mortality worldwide, necessitating novel, innovative therapeutics that address the current challenges of increasing antimicrobial resistance. Similar to cancer pathogenesis, infectious pathogens successfully fashion a hospitable environment within the host and modulate host metabolic functions to support their nutritional requirements, while suppressing host defenses by altering regulatory mechanisms. These parallels, and the advances made in targeted therapy in cancer, may inform the rational development of therapeutic interventions for infectious diseases. Although "immunotherapy" is habitually associated with the treatment of cancer, this review accentuates the evolving role of key targeted immune interventions that are approved, as well as those in development, for various cancers and infectious diseases. The general features of adoptive therapies, those that enhance T cell effector function, and ligand-based therapies, that neutralize or eliminate diseased cells, are discussed in the context of specific diseases that, to date, lack appropriate remedial treatment; cancer, HIV, TB, and drug-resistant bacterial and fungal infections. The remarkable diversity and versatility that distinguishes immunotherapy is emphasized, consequently establishing this approach within the armory of curative therapeutics, applicable across the disease spectrum.
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Affiliation(s)
- Krupa Naran
- Medical Biotechnology and Immunotherapy Unit, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Trishana Nundalall
- Medical Biotechnology and Immunotherapy Unit, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Shivan Chetty
- Medical Biotechnology and Immunotherapy Unit, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Stefan Barth
- Medical Biotechnology and Immunotherapy Unit, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- South African Research Chair in Cancer Biotechnology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
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7
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Bongomin F, Oladele RO, Gago S, Moore CB, Richardson MD. A systematic review of fluconazole resistance in clinical isolates of Cryptococcus species. Mycoses 2018; 61:290-297. [PMID: 29377368 DOI: 10.1111/myc.12747] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 01/16/2018] [Accepted: 01/16/2018] [Indexed: 12/30/2022]
Abstract
Fluconazole is the most commonly used antifungal agent for both the treatment of cryptococcal meningitis, and for prophylaxis against the disease. However, its prolonged use has the potential to exert selection pressure in favour of fluconazole-resistant strains. We evaluated the prevalence of fluconazole resistance in Cryptococcus spp. clinical isolates in 29 studies from 1988 to May 2017 included in EMBASE and MEDLINE databases. A total of 4995 Cryptococcus isolates from 3210 patients constituted this study; 248 (5.0%) of the isolates from relapsed episodes of cryptococcosis were included in this analysis. Eleven (38%) of the studies used minimum inhibitory concentrations (MICs) breakpoints of ≥64 μg/mL to define fluconazole resistance, 6 (21%) used ≥32 μg/mL, 11 (38%) used ≥16 μg/mL and 1 (3%) used ≤20 μg/mL. Overall, mean prevalence of fluconazole resistance was 12.1% (95% confidence interval [CI]: 6.7-17.6) for all isolates (n = 4995). Mean fluconazole resistance was 10.6% (95% CI: 5.5-15.6) for the incident isolates (n = 4747) and 24.1% (95% CI: -3.1-51.2) for the relapse isolates (n = 248). Of the 4995 isolates, 936 (18.7%) had MICs above the ecological cut-off value. Fluconazole resistance appears to be an issue in Cryptococcus isolates from patients with relapses. It remains unclear whether relapses occur due to resistance or other factors. There is an urgent need to establish antifungal breakpoints for Cryptococcus spp.
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Affiliation(s)
- Felix Bongomin
- Division of Infection, Immunity and Respiratory Medicine, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.,The National Aspergillosis Centre & NHS Mycology Reference Centre-Manchester, ECMM Center of Excellence in Clinical and Laboratory Mycology and Clinical Studies, Wythenshawe Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Rita O Oladele
- Division of Infection, Immunity and Respiratory Medicine, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.,Department of Medical Microbiology and Parasitology, College of Medicine, University of Lagos, Lagos, Nigeria
| | - Sara Gago
- Division of Infection, Immunity and Respiratory Medicine, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.,Manchester Fungal Infection Group, Division of Infection, Immunity and Respiratory Medicine, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Caroline B Moore
- Division of Infection, Immunity and Respiratory Medicine, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.,The National Aspergillosis Centre & NHS Mycology Reference Centre-Manchester, ECMM Center of Excellence in Clinical and Laboratory Mycology and Clinical Studies, Wythenshawe Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Malcolm D Richardson
- Division of Infection, Immunity and Respiratory Medicine, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.,The National Aspergillosis Centre & NHS Mycology Reference Centre-Manchester, ECMM Center of Excellence in Clinical and Laboratory Mycology and Clinical Studies, Wythenshawe Hospital, Manchester University NHS Foundation Trust, Manchester, UK
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8
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Oladele RO, Bongomin F, Gago S, Denning DW. HIV-Associated Cryptococcal Disease in Resource-Limited Settings: A Case for "Prevention Is Better Than Cure"? J Fungi (Basel) 2017; 3:jof3040067. [PMID: 29371581 PMCID: PMC5753169 DOI: 10.3390/jof3040067] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 11/21/2017] [Accepted: 11/30/2017] [Indexed: 11/18/2022] Open
Abstract
Cryptococcal disease remains a significant source of global morbidity and mortality for people living with HIV, especially in resource-limited settings. The recently updated estimate of cryptococcal disease revealed a global incidence of 223,100 cases annually with 73% of these cases being diagnosed in sub-Saharan Africa. Furthermore, 75% of the estimated 181,100 deaths associated with cryptococcal disease occur in sub-Saharan Africa. Point-of-care diagnostic assays have revolutionised the diagnosis of this deadly opportunistic infection. The theory of asymptomatic cryptococcal antigenaemia as a forerunner to symptomatic meningitis and death has been conclusively proven. Thus, cryptococcal antigenaemia screening coupled with pre-emptive antifungal therapy has been demonstrated as a cost-effective strategy with survival benefits and has been incorporated into HIV national guidelines in several countries. However, this is yet to be implemented in a number of other high HIV burden countries. Flucytosine-based combination therapy during the induction phase is associated with improved survival, faster cerebrospinal fluid sterilisation and fewer relapses. Flucytosine, however, is unavailable in many parts of the world. Studies are ongoing on the efficacy of shorter regimens of amphotericin B. Early diagnosis, proactive antifungal therapy with concurrent management of raised intracranial pressure creates the potential to markedly reduce mortality associated with this disease.
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Affiliation(s)
- Rita O Oladele
- Division of Infection, Immunity and Respiratory Medicine, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PL, UK.
- Department of Microbiology and Parasitology, College of Medicine, University of Lagos, Lagos ,P.O.Box 132, Nigeria.
- Global Action Fund for Fungal Infections, 1211 Geneva 1, Switzerland.
| | - Felix Bongomin
- Division of Infection, Immunity and Respiratory Medicine, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PL, UK.
- Global Action Fund for Fungal Infections, 1211 Geneva 1, Switzerland.
- The National Aspergillosis Center, Education and Research Centre, Wythenshawe Hospital, Manchester University NHS Foundation Trust, Manchester M23 9LT, UK.
| | - Sara Gago
- Division of Infection, Immunity and Respiratory Medicine, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PL, UK.
- Global Action Fund for Fungal Infections, 1211 Geneva 1, Switzerland.
- Manchester Fungal Infection Group, Core Technology Facility, The University of Manchester, Manchester M13 9PL, UK.
| | - David W Denning
- Division of Infection, Immunity and Respiratory Medicine, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PL, UK.
- Global Action Fund for Fungal Infections, 1211 Geneva 1, Switzerland.
- The National Aspergillosis Center, Education and Research Centre, Wythenshawe Hospital, Manchester University NHS Foundation Trust, Manchester M23 9LT, UK.
- Manchester Fungal Infection Group, Core Technology Facility, The University of Manchester, Manchester M13 9PL, UK.
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Molecular Characterization and Antifungal Susceptibility Testing of Sequentially Obtained Clinical Cryptococcus deneoformans and Cryptococcus neoformans Isolates from Ljubljana, Slovenia. Mycopathologia 2017; 183:371-380. [PMID: 29064061 DOI: 10.1007/s11046-017-0214-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Accepted: 10/15/2017] [Indexed: 12/22/2022]
Abstract
AIM To retrospectively investigate the epidemiology of cryptococcosis in Ljubljana, Slovenia. METHODOLOGY Forty-six sequentially obtained isolates from 19 patients were subjected to amplified fragment length polymorphism (AFLP) genotyping, microsatellite typing, mating- and serotype PCRs and antifungal susceptibility testing. RESULTS Majority of the isolates were Cryptococcus deneoformans (n = 29/46; 63%) followed by Cryptococcus neoformans (n = 16/46; 34.8%) and their interspecies hybrid (n = 1/46; 2.2%). Mating-type α was predominant, two mating-type a C. deneoformans isolates and one mating-type a/α isolate were observed. Several mixed infections were found by microsatellite typing; one patient had a persisting C. deneoformans infection for > 2.5 years. For C. deneoformans, the in vitro antifungal MIC90 and susceptibility ranges were for amphotericin B 0.25 µg/ml (0.031-0.25 µg/ml), 5-fluorocytosine 0.25 µg/ml (0.063-4 µg/ml), fluconazole 8 µg/ml (0.5-16 µg/ml), voriconazole 0.063 µg/ml (0.008-0.125 µg/ml), posaconazole 0.063 µg/ml (0.008-0.063 µg/ml) and itraconazole 0.063 µg/ml (0.031-0.125 µg/ml). For C. neoformans, these values were for amphotericin B 0.25 µg/ml (0.063-0.5 µg/ml), 5-fluorocytosine 1 µg/ml (0.063-1 µg/ml), fluconazole 16 µg/ml (0.5-64 µg/ml), voriconazole 0.125 µg/ml (0.008-0.25 µg/ml), posaconazole 0.063 µg/ml (0.008-0.063 µg/ml) and itraconazole 0.063 µg/ml (0.031-0.125 µg/ml). CONCLUSIONS Majority of the cases were caused by C. deneoformans; mating-type α was predominant. Several mixed infections were identified by AFLP genotyping and microsatellite typing. Despite antifungal therapy, a cryptococcal isolate could persist for years. Voriconazole, itraconazole and posaconazole were the most potent antifungal drugs.
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10
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Ferreira GF, Santos DA. Heteroresistance and fungi. Mycoses 2017; 60:562-568. [PMID: 28660647 DOI: 10.1111/myc.12639] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 04/07/2017] [Accepted: 05/10/2017] [Indexed: 11/27/2022]
Abstract
The concept of heteroresistance refers to the heterogeneous susceptibility to an antimicrobial drug in a microorganism population, meaning that some clones may be resistant and others are susceptible. This phenomenon has been widely studied in bacteria, but little attention has been given to its expression in fungi. We review the available literature on heteroresistance in fungi and invite the reader to recognise this phenomenon as a fungal mechanism to adapt to environmental stress, which may interfere both in resistance and virulence. Finally, heteroresistance may explain the treatment failures to eradicate mycosis in some patients treated with a seemingly appropriate antifungal.
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Affiliation(s)
- Gabriella F Ferreira
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Governador Valadares, Brazil.,Departamento de Farmácia, Universidade Federal de Juiz de Fora - Campus Governador Valadares, Governador Valadares, Brazil
| | - Daniel A Santos
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Governador Valadares, Brazil
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11
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Bouklas T, Diago-Navarro E, Wang X, Fenster M, Fries BC. Characterization of the virulence of Cryptococcus neoformans strains in an insect model. Virulence 2015; 6:809-13. [PMID: 26364757 DOI: 10.1080/21505594.2015.1086868] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Tejas Bouklas
- a Department of Medicine (Division of Infectious Diseases) ; Stony Brook University ; Stony Brook , NY USA
| | - Elizabeth Diago-Navarro
- a Department of Medicine (Division of Infectious Diseases) ; Stony Brook University ; Stony Brook , NY USA
| | - Xiaobo Wang
- b Department of Medicine (Division of Infectious Diseases) ; Albert Einstein College of Medicine of Yeshiva University ; Bronx , NY USA
| | - Marc Fenster
- b Department of Medicine (Division of Infectious Diseases) ; Albert Einstein College of Medicine of Yeshiva University ; Bronx , NY USA
| | - Bettina C Fries
- a Department of Medicine (Division of Infectious Diseases) ; Stony Brook University ; Stony Brook , NY USA.,b Department of Medicine (Division of Infectious Diseases) ; Albert Einstein College of Medicine of Yeshiva University ; Bronx , NY USA.,c Department of Microbiology and Molecular Genetics ; Stony Brook University ; Stony Brook , NY USA.,d Department of Microbiology and Immunology ; Albert Einstein College of Medicine of Yeshiva University ; Bronx , NY USA
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12
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Amphotericin B stimulates γδ T and NK cells, and enhances protection from Salmonella infection. Innate Immun 2015; 21:598-608. [DOI: 10.1177/1753425914567692] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 12/15/2014] [Indexed: 11/15/2022] Open
Abstract
Amphotericin B (AmB) is a commonly used antifungal drug, with well-documented effects on cellular immune responses. We determined that AmB-stimulated γδ T-cell activation and proliferation in vitro at very low concentrations. AmB also enhanced IFN-γ production by NK cells in combination with IL-18. AmB had a greater effect on IFN-γ production in cells isolated from very young animals. Although innate immunostimulatory aspects of AmB have been defined, AmB has not been extensively applied in non-fungal infection settings. Given that γδ T cells are increased and activated in Salmonella infection in cattle, we assessed the effects of AmB in protection from Salmonella enterocolitis in calves. One injection of AmB, at approximately one-tenth of the concentration used in human patients to counter fungal infection, or saline control, was delivered intravenously to calves prior to infection with Salmonella. This single injection caused no adverse effects, reduced disease symptoms from Salmonella enterocolitis and significantly reduced Salmonella bacteria shed in feces of infected animals. Our findings suggest that AmB may be an inexpensive and readily available prophylactic approach for the prevention of bacterial infection in calves.
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13
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Mahabeer Y, Chang CC, Naidu D, Dorasamy A, Lewin S, Ndung'u T, Moosa MY, French M, Mlisana K, Coovadia Y. Comparison of Etests and Vitek 2 ® to broth microdilution for the susceptibility testing of Cryptococcus neoformans. Diagn Microbiol Infect Dis 2014; 80:294-8. [PMID: 25277745 DOI: 10.1016/j.diagmicrobio.2014.09.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 08/15/2014] [Accepted: 09/06/2014] [Indexed: 11/29/2022]
Abstract
We determined the susceptibility of 102 clinical isolates Cryptococcus neoformans from Durban, South Africa, to amphotericin B, fluconazole, flucytosine, and voriconazole using broth microdilution (BMD) according to the Clinical and Laboratory Standards Institute M27-A3 document and compared these results with Etest and Vitek 2(®). Essential agreement (EA) of Etest and Vitek 2(®) compared to BMD was determined. Low MICs that were below the epidemiological cutoff values of the 4 antifungal agents tested were demonstrated by all isolates. The EA of Etests for fluconazole, amphotericin, and voriconazole was 95.1%, 83.3%, and 91.2%, respectively, and for Vitek 2(®) EA for fluconazole, amphotericin, and flucytosine was 97.1%, 95.1%, and 97.1%, respectively. The Vitek 2(®) showed good agreement with BMD and is a suitable alternative. Etests demonstrated good EA for azoles only. Clinical cryptococcal isolates from Durban remain susceptible to current recommended antifungal therapy.
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Affiliation(s)
- Yesholata Mahabeer
- Department of Medical Microbiology, National Health Laboratory Services, Durban, South Africa; School of Laboratory Medicine and Medical Sciences, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa.
| | - Christina C Chang
- Department of Infectious Diseases, Alfred Hospital, Monash University, Melbourne, Australia; Centre of Biomedical Research, Burnet Institute, Melbourne, Australia; HIV Pathogenesis Programme, University of KwaZulu-Natal, Durban, South Africa
| | - Dianithi Naidu
- Department of Medical Microbiology, National Health Laboratory Services, Durban, South Africa
| | - Afton Dorasamy
- KwaZulu-Natal Research Institute for Tuberculosis and HIV, Durban, South Africa
| | - Sharon Lewin
- Department of Infectious Diseases, Alfred Hospital, Monash University, Melbourne, Australia; Centre of Biomedical Research, Burnet Institute, Melbourne, Australia
| | - Thumbi Ndung'u
- School of Laboratory Medicine and Medical Sciences, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa; HIV Pathogenesis Programme, University of KwaZulu-Natal, Durban, South Africa; KwaZulu-Natal Research Institute for Tuberculosis and HIV, Durban, South Africa
| | - Mohammed-Yunus Moosa
- Department of Infectious Diseases, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
| | - Martyn French
- School of Pathology and Laboratory Medicine, University of Western Australia, Perth, Australia; Department of Clinical Immunology, Royal Perth Hospital and PathWest Laboratory Medicine, Perth, Australia
| | - Koleka Mlisana
- Department of Medical Microbiology, National Health Laboratory Services, Durban, South Africa; School of Laboratory Medicine and Medical Sciences, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
| | - Yacoob Coovadia
- Department of Medical Microbiology, National Health Laboratory Services, Durban, South Africa; School of Laboratory Medicine and Medical Sciences, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
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14
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Abstract
Does cell age matter in virulence? The emergence of persister cells during chronic infections is critical for persistence of infection, but little is known how this occurs. Here, we demonstrate for the first time that the replicative age of the fungal pathogen Cryptococcus neoformans contributes to persistence during chronic meningoencephalitis. Generationally older C. neoformans cells are more resistant to hydrogen peroxide stress, macrophage intracellular killing, and antifungal agents. Older cells accumulate in both experimental rat infection and in human cryptococcosis. Mathematical modeling supports the concept that the presence of older C. neoformans cells emerges from in vivo selection pressures. We propose that advanced replicative aging is a new unanticipated virulence trait that emerges during chronic fungal infection and facilitates persistence. Therapeutic interventions that target old cells could help in the clearance of chronic infections. Our findings that the generational age of Cryptococcus neoformans cells matters in pathogenesis introduces a novel concept to eukaryotic pathogenesis research. We propose that emerging properties of aging C. neoformans cells and possibly also other fungal pathogens contribute to persistence and virulence. Whereas the replicative life span of strains may not matter for virulence per se, age-related resilience and thus the generational age of individual C. neoformans cells within a pathogen population could greatly affect persistence of the pathogen population and therefore impact outcome.
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Redlich S, Ribes S, Schütze S, Eiffert H, Nau R. Toll-like receptor stimulation increases phagocytosis of Cryptococcus neoformans by microglial cells. J Neuroinflammation 2013; 10:71. [PMID: 23738865 PMCID: PMC3693974 DOI: 10.1186/1742-2094-10-71] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2013] [Accepted: 05/22/2013] [Indexed: 02/07/2023] Open
Abstract
Background Toll-Like receptors (TLRs) belong to the family of pattern-recognition receptors with a crucial function of recognising pathogen-associated molecular patterns (PAMPs). Cryptococcal meningitis is a potentially fatal disease with a high mortality and risk of neurological sequelae. Methods We studied the ability of microglial cells to increase the phagocytosis of cryptococci after stimulation with agonists of TLR1/2, TLR3, TLR4 and TLR9. Results Stimulation of murine microglial cells with these TLR agonists for 24 h increased the phagocytosis of encapsulated Cryptococcus neoformans. Stimulation increased the release of TNF-α, CXCL1 (KC), IL-6, IL-10 and MIP-2, which indicated the activation of microglial cells. Unstimulated and TLR agonist-stimulated MyD88-deficient cells showed a reduced ability to phagocytose cryptococci compared to their wild-type counterpart. Intracellular killing of cryptococci was also increased in TLR-stimulated cells compared to unstimulated microglial cells. Conclusion Our observation suggests that stimulation of microglial cells by TLR agonists can increase the resistance of the brain against CNS infections caused by Cryptococcus neoformans. This may be of interest when an immunocompromised patient is unable to eliminate Cryptococcus neoformans despite antifungal therapy.
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Affiliation(s)
- Sandra Redlich
- Institute of Neuropathology, University Medical Center, Göttingen, Germany.
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16
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Pfaller MA, Castanheira M, Diekema DJ, Messer SA, Jones RN. Wild-type MIC distributions and epidemiologic cutoff values for fluconazole, posaconazole, and voriconazole when testing Cryptococcus neoformans as determined by the CLSI broth microdilution method. Diagn Microbiol Infect Dis 2011; 71:252-9. [DOI: 10.1016/j.diagmicrobio.2011.07.007] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Accepted: 07/25/2011] [Indexed: 12/16/2022]
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17
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Mlinarić-Missoni E, Hagen F, Chew WHM, Važić-Babić V, Boekhout T, Begovac J. In vitro antifungal susceptibilities and molecular typing of sequentially isolated clinical Cryptococcus neoformans strains from Croatia. J Med Microbiol 2011; 60:1487-1495. [DOI: 10.1099/jmm.0.031344-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Affiliation(s)
- Emilija Mlinarić-Missoni
- Croatian National Institute of Public Health, Reference Centre for Diagnostics of Systemic Mycoses, Zagreb, Croatia
| | - Ferry Hagen
- Department of Internal Medicine and Infectious Diseases, University Medical Center, Utrecht, The Netherlands
- CBS Fungal Biodiversity Centre, Department of Yeast and Basidiomycete Research, Utrecht, The Netherlands
| | | | - Verica Važić-Babić
- Croatian National Institute of Public Health, Reference Centre for Diagnostics of Systemic Mycoses, Zagreb, Croatia
| | - Teun Boekhout
- Department of Internal Medicine and Infectious Diseases, University Medical Center, Utrecht, The Netherlands
- CBS Fungal Biodiversity Centre, Department of Yeast and Basidiomycete Research, Utrecht, The Netherlands
| | - Josip Begovac
- Department of Infectious Diseases, University of Zagreb School of Medicine, Zagreb, Croatia
- University Hospital for Infectious Diseases, Zagreb, Croatia
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18
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Ochiuzzi ME, Santiso GM, Arechavala AI. Correlation of Etest and Neo-Sensitabs diffusion assays on Mueller-Hinton-methylene blue agar with broth microdilution reference method (CLSI-M27-A2) for testing susceptibilities of Cryptococcus neoformans to amphotericin B and fluconazole. Med Mycol 2010; 48:893-6. [PMID: 20370370 DOI: 10.3109/13693781003733750] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Cryptococcus neoformans causes disseminated infection in 7-8% of HIV positive patients admitted to Hospital F. J. Muñiz in Buenos Aires. Meningoencephalitis is the most frequent clinical manifestation and is one of the main causes of death in those patients with AIDS. The standard treatment for this mycosis consists of amphotericin B followed by fluconazole until two successive cultures of CFS are negative. Although resistance to these drugs is infrequent, minimal inhibitory concentrations (MIC) of some antifungals can be high. Since it is important to know the susceptibility levels of this fungus to the antifungal drugs usually employed in our institution, we analyzed the susceptibility test results of C. neoformans with two diffusion methods (Etest and NeoSensitabs tablets) employing Mueller-Hinton agar with 2% glucose and 0.5 microg/ml methylene blue. These results were compared with MICs obtained through the use of the broth microdilution reference method (CLSI). Results showed good agreement with the reference method, with no very major errors and only two major errors for fluconazole using NeoSensitabs tablets. For all the above mentioned, we confirm the usefulness of Mueller-Hinton agar to evaluate C. neoformans susceptibility to amphotericin B and fluconazole with these two agar diffusion methods.
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Affiliation(s)
- Maria Eugenia Ochiuzzi
- Mycology Unit, Infectious Diseases, Hospital F. J. Muñiz, Uspallata 2272 (1282), Buenos Aires, Argentina
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19
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Illnait-Zaragozí MT, Martínez-Machín GF, Fernández-Andreu CM, Hagen F, Boekhout T, Klaassen CHW, Meis JF. Microsatellite typing and susceptibilities of serial Cryptococcus neoformans isolates from Cuban patients with recurrent cryptococcal meningitis. BMC Infect Dis 2010; 10:289. [PMID: 20920321 PMCID: PMC2959061 DOI: 10.1186/1471-2334-10-289] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Accepted: 10/04/2010] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Cryptococcus neoformans is commonly associated with meningoencephalitis in immunocompromised patients and occasionally in apparently healthy individuals. Recurrence of infection after initial treatment is not uncommon. We studied C. neoformans isolates from 7 Cuban patients with recurrent cryptococcal meningitis. Antifungal susceptibility and genotyping with microsatellite molecular typing were carried out. METHODS Isolates (n = 19) were recovered from cerebrospinal fluid, blood, urine and semen. Antifungal susceptibilities for amphotericin B, fluconazole, flucytosine, itraconazole, voriconazole, posaconazole and isavuconazole were tested by CLSI M27A3 broth microdilution method. Genotyping was done using a panel of 9 microsatellite (STR) markers: (CT)n, (TG)n, (TA)n, (CTA)n, (TCT)n, (CCA)n, (TTAT)n, (ATCC)n and (TATT)n. RESULTS The average number of isolates/patient was 2.71. The mean time interval between the collection of any two isolates was 52.5 days. All strains were identified as C. neoformans var. grubii (serotype Aα). Although none of the strains were resistant to the studied drugs, in serial isolates from two patients, MICs values of triazoles increased 4-5 log2 dilutions over time. STR patterns showed 14 distinctive profiles. In three patients the recurrent infection was associated with genotypically identical isolates. The four other patients had relapse isolates which were genotypically different from the initial infecting strain. CONCLUSION Recurrences of cryptococcal meningitis in our series of patients was not associated with development of drug resistance of the original strain but by an initial infection with different strains or a reinfection with a new strain.
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20
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Drew RH, Townsend ML. Antifungal Drug Resistance: Clinical Relevance and Impact of Antifungal Drug Use. CURRENT FUNGAL INFECTION REPORTS 2010. [DOI: 10.1007/s12281-010-0013-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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21
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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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22
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Braga FG, Bouzada MLM, Fabri RL, de O Matos M, Moreira FO, Scio E, Coimbra ES. Antileishmanial and antifungal activity of plants used in traditional medicine in Brazil. JOURNAL OF ETHNOPHARMACOLOGY 2007; 111:396-402. [PMID: 17234373 DOI: 10.1016/j.jep.2006.12.006] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2006] [Revised: 11/25/2006] [Accepted: 12/02/2006] [Indexed: 05/09/2023]
Abstract
The antileishmanial and antifungal activity of 24 methanol extracts from 20 plants, all of them used in the Brazilian traditional medicine for the treatment of several infectious and inflammatory disorders, were evaluated against promastigotes forms of two species of Leishmania (L. amazonensis and L. chagasi) and two yeasts (Candida albicans and Cryptococcus neoformans). Among the 20 tested methanolic extracts, those of Vernonia polyanthes was the most active against L. amazonensis (IC(50) of 4 microg/ml), those of Ocimum gratissimum exhibited the best activity against L. chagasi (IC(50) of 71 microg/ml). Concerning antifungical activity, Schinus terebintifolius, O. gratissimum, Cajanus cajan, and Piper aduncum extracts were the most active against C. albicans (MIC of 1.25 mg/ml) whereas Bixa orellana, O. gratissimum and Syzygium cumini exhibited the best activity against C. neoformans (MIC of 0.078 mg/ml).
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Affiliation(s)
- Fernanda G Braga
- Departamento de Parasitologia, Microbiologia e Imunologia, ICB, Universidade Federal de Juiz de Fora, Juiz de Fora, MG, Brazil
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23
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Abdel-Salam HA. In vitro susceptibility of Cryptococcus neoformans clinical isolates from Egypt to seven antifungal drugs. Mycoses 2005; 48:327-32. [PMID: 16115103 DOI: 10.1111/j.1439-0507.2005.01137.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The in vitro susceptibility of 29 clinical isolates of Cryptococcus neoformans to fluconazole, miconazole, itraconazole, ketoconazole, flucytosine, nystatin and amphotericin B was tested by broth and colorimetric microdilution methods. Most of the isolates showed uniform patterns of susceptibility to the used antifungal agents. Only three isolates exhibited resistance [fourfold or greater rise in the minimum inhibitory concentrations (MICs)] to the tested antifungal drugs. The MIC50 and MIC90 were 0.5-8 mg l(-1) for 5-flucytosine, 0.2-8.25 mg l(-1) for nystatin, 0.5-16 mg l(-1) for fluconazole and 0.2-12.5 mg l(-1) for miconazole. However, MIC50 and MIC90 were in narrow range for the clinical yeast isolates in both methods used and showed 0.5-1 mg l(-1) for amphotericin B and 0.016-0.25 mg l(-1) for both ketoconazole and itraconazole. The combination of fluconazole plus flucytosine showed greater synergistic and fungicidal activity compared with that of fluconazole plus amphotericin B or the use of individual drugs.
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Affiliation(s)
- Hassan A Abdel-Salam
- Department of Microbiology, Faculty of Pharmacy, University of Zagazig, Zagazig, Egypt.
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24
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Fung-Tomc JC, Bonner DP. Recent developments in pradimicin-benanomicin and triazole antibiotics. Expert Opin Investig Drugs 2005; 6:129-45. [PMID: 15989596 DOI: 10.1517/13543784.6.2.129] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Fungal infections are on the rise as the number of patients with compromised immune systems continues to increase. The need for safer and more effective antifungals has resulted in the search for novel drug classes and for modifications to existing classes, with the aim of enhancing their antifungal spectra and potency. In this review, two classes of antifungals are discussed: the pradimicin-benanomicin antibiotics and the newer triazole derivatives. These have activity against Candida spp., Cryptococcus neoformans and Aspergillus spp., as well as variable activity against other less commonly encountered fungi including Pneumocystis carinii. Pradimicins-benanomicins are generally fungicidal, whereas the newer azoles appear to be selectively fungicidal to Cryptococcus neoformans and Aspergillus spp. Pradimicin-benanomicin acts by binding to mannan and alters membrane integrity. One water-soluble pradimicin candidate, BMS-181184, has been selected for clinical development. The triazoles act by inhibiting cytochrome P450 sterol 14a-demethylase. Four triazoles either currently in clinical development (voriconazole and D0870) or being considered as clinical candidates (ER-30346 and Sch 56592) will be discussed. The antifungal spectra, pharmacokinetic and toxicologic data in animals, and efficacy results in experimental infection models will be reviewed for BMS-181184 and the four newer triazoles. Results from the early clinical trials for voriconazole and D0870 will also be discussed.
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Affiliation(s)
- J C Fung-Tomc
- Bristol-Myers Squibb Pharmaceutical Research Institute, Wallingford, Connecticut 06492-7660, USA
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25
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Pfaller MA, Messer SA, Boyken L, Rice C, Tendolkar S, Hollis RJ, Diekema DJ. Evaluation of the NCCLS M44-P Disk Diffusion Method for Determining Susceptibilities of 276 Clinical Isolates of
Cryptococcus neoformans
to Fluconazole. J Clin Microbiol 2004; 42:380-3. [PMID: 14715784 PMCID: PMC321716 DOI: 10.1128/jcm.42.1.380-383.2004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
ABSTRACT
We evaluated the NCCLS M44-P fluconazole disk diffusion method in comparison with the NCCLS M27-A2 broth microdilution method for determining the susceptibility of 276 isolates of
Cryptococcus neoformans
. Disk diffusion testing was performed using Mueller-Hinton agar supplemented with 2% glucose and 0.5 μg of methylene blue/ml. Among the 276 isolates, 259 (93.8%) were susceptible, 16 (5.8%) were susceptible—dose dependent, and 1 (0.4%) was resistant to fluconazole as determined by the NCCLS broth microdilution method. The overall categorical agreement between the two methods was 86%, with 0% very major errors, 2% major errors, and 12% minor errors. The disk diffusion method using Mueller-Hinton agar supplemented with glucose and methylene blue appears to be a useful approach for determining the fluconazole susceptibility of C.
neoformans.
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Affiliation(s)
- M A Pfaller
- Department of Pathology, Roy J and Lucille A Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA.
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26
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Moraes EMP, Prímola NS, Hamdan JS. Antifungal susceptibility of clinical and environmental isolates of Cryptococcus neoformans to four antifungal drugs determined by two techniques. Mycoses 2003; 46:164-8. [PMID: 12801356 DOI: 10.1046/j.1439-0507.2003.00872.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A total of 64 Cryptococcus neoformans strains, including clinical and environmental Brazilian isolates var. neoformans and var. gattii, were tested for susceptibility to amphotericin B, 5-flucytosine, fluconazole and itraconazole. The tests were performed according to the recommendations of National Committee of Clinical Laboratory Standards and the method of macrodilution in liquid medium of Shadomy et al. [Manual de Microbiologia Clínica, 4th ed. Buenos Aires: Editorial Medica Panamericana, 1987: 1229-38]. For most drugs there was a significant difference between the readings taken at 24 and 48 h with both methods. When the minimum inhibitory concentrations obtained by the two techniques were compared, significant differences were observed for amphotericin B and fluconazole. Overall, differences in drug susceptibility with respect to the origin of the isolates or the variety of the fungus were not observed. As an exception, the gattii variety exhibited a high resistance rate to amphotericin B when the technique of Shadomy et al. was applied, a fact possibly related to the greater difficulty for treatment of the disease caused by this fungal variety.
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Affiliation(s)
- E M P Moraes
- Department of Microbiology, Institute of Biological Sciences, Minas Gerais, Brazil
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27
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Abstract
The increasing incidence of invasive fungal infections is the result of many factors, including an increasing number of patients with severe immunosuppression. Although new drugs have been introduced to combat this problem, the development of resistance to antifungal drugs has become increasingly apparent, especially in patients who require long-term treatment or who are receiving antifungal prophylaxis, and there is growing awareness of shifts of flora to more-resistant species. The frequency, interpretation, and, in particular, mechanism of resistance to current classes of antifungal agents, particularly the azoles (where resistance has climbed most prominently) are discussed in this review.
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Affiliation(s)
- Juergen Loeffler
- Eberhard-Karls-Universität, Medizinische Klinik, Tuebingen, Germany
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28
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Abstract
Cryptococcus neoformans has risen to a worldwide highly recognizable major opportunistic pathogen with deadly consequences. It has become a model fungus to study a variety of paradigms in the host-fungus relationships. Genomic studies are advancing knowledge on its evolution and dissecting its virulence composite. Studies designed to understand host immunology to this fungus are leading to development of active and passive prevention and therapeutic strategies. This article collates and analyzes both new and old knowledge about the pathogen to help frame the meaning of human cryptococcosis as it starts to evolve in the new millennium.
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Affiliation(s)
- John R Perfect
- Department of Medicine, Division of Infectious Diseases, Duke University Medical Center, PO Box 3353, Durham, NC 27710, USA.
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29
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Yildiran ST, Fothergill AW, Sutton DA, Rinaldi MG. In vitro susceptibilities of cerebrospinal fluid isolates of Cryptococcus neoformans collected during a ten-year period against fluconazole, voriconazole and posaconazole (SCH56592). Mycoses 2002; 45:378-83. [PMID: 12421285 DOI: 10.1046/j.1439-0507.2002.00765.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We investigated the in vitro susceptibilities of 213 cerebrospinal fluid isolates of Cryptococcus neoformans isolated from 192 patients through a 10-year period, 1990-99, against fluconazole, voriconazole and posaconazole (SCH56592) by using the NCCLS (National Committee for Clinical Laboratory Standards) macrodilution method, M27-A. The overall MICs50 and MICs90 of fluconazole, voriconazole and posaconazole were found to be 2 and 8 micro g ml-1, <or=0.125 micro g ml-1 (both), and <or=0.015 and 0.06 micro g ml-1, respectively. The MIC ranges, MICs50, and MICs90 of three triazoles were also determined according to the defined year category (1990-94, 1995, 1996, 1997 and 1998-99). The MICs50 and MICs90 of each triazole remained almost unchanged and did not exhibit any sign of an upward shift during a decade (1990-99). However, a tendency for development of possible cross-resistance between the three triazoles was observed only in 1996. Meanwhile, the individual relapsing isolates (n:21) from 20 patients exhibited same, higher or, suprisingly, lower MICs, particularly against fluconazole and posaconazole.
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Affiliation(s)
- S T Yildiran
- Department of Pathology, University of Texas Health Science Center, San Antonio, Texas,
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30
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Abstract
Pathogenic fungi are the cause of life-threatening infections in an increasing number of immunocompromised patients. The intrinsic resistance to antifungal therapy observed in some genera, along with the development of resistance during treatment in others, is becoming a major problem in the management of these diseases. We reviewed the epidemiology of the most common systemic fungal infections for which antifungal resistance is a potential problem, the mechanisms of antifungal resistance, the correlation between in vitro susceptibility testing and clinical outcome, and the clinical implications of antifungal resistance.
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Affiliation(s)
- Sofia Perea
- Department of Medicine, Division of Infectious Diseases, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
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31
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Abstract
Pathogenic fungi have many complex mechanisms of resistance to antifungal drugs. Information about the clinical, cellular, and molecular factors contributing to antifungal-drug resistance continues to accumulate. We critically review the diagnosis, epidemiology, and mechanisms of antifungal drug resistance of pathogenic fungi. Better understanding of this resistance should assist in developing better detection strategies for preventing and treating refractory mycoses in the future.
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Affiliation(s)
- Dimitrios P Kontoyiannis
- Department of Infectious Diseases, Infection Control and Employee Health, University of Texas M D Anderson Cancer Center, Houston, TX 77030, USA.
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32
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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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Blakely G, Hekman J, Chakraburtty K, Williamson PR. Evolutionary divergence of an elongation factor 3 from Cryptococcus neoformans. J Bacteriol 2001; 183:2241-8. [PMID: 11244063 PMCID: PMC95130 DOI: 10.1128/jb.183.7.2241-2248.2001] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Elongation factor 3 (EF3) is considered a promising drug target for the control of fungal diseases because of its requirement for protein synthesis and survival of fungi and a lack of EF3 in the mammalian host. However, EF3 has been characterized only in ascomycete yeast. In order to understand the role of EF3 in a basidiomycete yeast, we cloned the gene encoding EF3 from Cryptococcus neoformans (CnEF3), an important fungal pathogen in immunocompromised patients, including those infected with human immunodeficiency virus. CnEF3 was found to encode a 1,055-amino-acid protein and has 44% identity with EF3 from Saccharomyces cerevisiae (YEF3). Expressed CnEF3 exhibited ATPase activity that was only modestly stimulated by ribosomes from S. cerevisiae. In contrast, CnEF3 showed tight binding to cryptococcal ribosomes, as shown by an inability to be removed under conditions which successfully remove Saccharomyces EF3 from ribosomes (0.5 M KCl or 2 M LiCl). CnEF3 also poorly complemented a YEF3 defect in a diploid null mutant and two temperature-sensitive mutants which have been shown previously to be complemented well by EF3 from other ascomycetes, such as Candida albicans. These data clearly identify the presence of a functioning EF3 in the basidiomycete yeast C. neoformans, which demonstrates an evolutionary divergence from EF3 of ascomycete yeast.
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Affiliation(s)
- G Blakely
- Division of Infectious Diseases, University of Illinois at Chicago College of Medicine, Chicago, Illinois 60612, USA
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Xu J, Onyewu C, Yoell HJ, Ali RY, Vilgalys RJ, Mitchell TG. Dynamic and heterogeneous mutations to fluconazole resistance in Cryptococcus neoformans. Antimicrob Agents Chemother 2001; 45:420-7. [PMID: 11158735 PMCID: PMC90307 DOI: 10.1128/aac.45.2.420-427.2001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Infections with the human pathogenic basidiomycetous yeast Cryptococcus neoformans are often treated with fluconazole. Resistance to this antifungal agent has been reported. This study investigated the patterns of mutation to fluconazole resistance in C. neoformans in vitro. The MIC of fluconazole was measured for 21 strains of C. neoformans. The MICs for these 21 strains differed (0.25 to 4.0 microg/ml), but the strains were selected for this study because they exhibited no growth on plates of yeast morphology agar (YMA) containing 8 microg of fluconazole per ml. To determine their mutation rates, six independent cultures from a single original colony were established for each of the 21 strains. Each culture was then spread densely on a YMA plate with 8 microg of fluconazole per ml. A random set of putative mutants was subcultured, and the MIC of fluconazole was determined for each mutant. The 21 strains evinced significant heterogeneity in their mutation rates. The MICs of the putative mutants ranged widely, from their original MIC to 64 microg of fluconazole per ml. However, for this set of 21 strains, there was no significant correlation between the original MIC for a strain and the mutation rate of that strain; the MIC for the mutant could not be predicted from the original MIC. These results suggest that dynamic and heterogeneous mutational processes are involved in generating fluconazole resistance in C. neoformans.
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Affiliation(s)
- J Xu
- Department of Microbiology, Duke University Medical Center, Durham, North Carolina 27710, USA.
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35
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Restrepo MI, Najvar LK, Barchiesi F, Luther MF, Graybill JR. Treatment of murine cryptococcal meningitis with UR-9751 and UR-9746. Med Mycol 2000; 38:221-4. [PMID: 10892990 DOI: 10.1080/mmy.38.3.221.224] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
In these studies, we compare the efficacy of two new azole antifungals with fluconazole in a murine model of cryptococcal meningitis. Mice were infected intracranially. Beginning one day later, groups of 7-10 mice were treated through to day 10 orally with UR-9751 or UR-9746 at 0.1, 0.25, 0.5, 1 or 10 mg kg(-1) day(-1) or fluconazole at 10 mg kg(-1) day(-1). At 10 mg kg(-1) day(-1), all three drugs prolonged survival over controls, but at 1 mg kg(-1) day(-1) only UR-9746 prolonged survival. Tissue counts were more varied on mice sacrificed 8 days after infection. In general, both UR drugs were equal or more potent than fluconazole, and UR-9751 was more effective than UR-9746.
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Affiliation(s)
- M I Restrepo
- University of Texas Health Science Center at San Antonio, 78284, USA
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36
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Aller AI, Martin-Mazuelos E, Lozano F, Gomez-Mateos J, Steele-Moore L, Holloway WJ, Gutiérrez MJ, Recio FJ, Espinel-Ingroff A. Correlation of fluconazole MICs with clinical outcome in cryptococcal infection. Antimicrob Agents Chemother 2000; 44:1544-8. [PMID: 10817706 PMCID: PMC89910 DOI: 10.1128/aac.44.6.1544-1548.2000] [Citation(s) in RCA: 132] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have correlated the in vitro results of testing the susceptibility of Cryptococcus neoformans to fluconazole with the clinical outcome after fluconazole maintenance therapy in patients with AIDS-associated cryptococcal disease. A total of 28 isolates of C. neoformans from 25 patients (24 AIDS patients) were tested. The MICs were determined by the broth microdilution technique by following the modified guidelines described in National Committee for Clinical Standards (NCCLS) document M27-A, e.g., use of yeast nitrogen base medium and a final inoculum of 10(4) CFU/ml. The fluconazole MIC at which 50% of isolates are inhibited (MIC(50)) and MIC(90), obtained spectrophotometrically after 48 h of incubation, were 4 and 16 microg/ml, respectively. Of the 25 patients studied, 4 died of active cryptococcal disease and 2 died of other causes. Therapeutic failure was observed in five patients who were infected with isolates for which fluconazole MICs were > or =16 microg/ml. Four of these patients had previously had oropharyngeal candidiasis (OPC); three had previously had episodes of cryptococcal infection, and all five treatment failure patients had high cryptococcal antigen titers in either serum or cerebrospinal fluid (titers, >1:4,000). Although 14 of the 18 patients who responded to fluconazole therapy had previously had OPC infections, they each had only a single episode of cryptococcal infection. It appears that the clinical outcome after fluconazole maintenance therapy may be better when the infecting C. neoformans strain is inhibited by lower concentrations of fluconazole for eradication (MICs, <16 microg/ml) than when the patients are infected with strains that require higher fluconazole concentrations (MICs, > or =16 microg/ml). These findings also suggest that the MICs determined by the modified NCCLS microdilution method can be potential predictors of the clinical response to fluconazole therapy and may aid in the identification of patients who will not respond to fluconazole therapy.
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Affiliation(s)
- A I Aller
- Service of Microbiology and Unit of Infectious Diseases, Valme University Hospital, Seville, Spain
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37
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Rodero L, Córdoba S, Cahn P, Soria M, Lucarini M, Davel G, Kaufman S, Canteros C, Guelfand L. Timed-kill curves for Cryptococcus neoformans isolated from patients with AIDS. Med Mycol 2000; 38:201-7. [PMID: 10892987 DOI: 10.1080/mmy.38.3.201.207] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Infection with Cryptococcus neoformans is an increasing problem in immunocompromised patients, particularly those with acquired immune deficiency syndrome (AIDS). Amphotericin B and fluconazole are currently acceptable therapies for cryptococcal meningitis; however, their effects remain suboptimal and recurrence or treatment failure is still a problem. Antifungal susceptibility testing may be an important tool for guiding therapy, but for C. neoformans, a reliable method is still not available. This retrospective study evaluated minimal inhibitory concentration (MIC) for amphotericin B and fluconazole, and minimal fungicidal concentration (MFC) and timed-kill curves for amphotericin B against 16 clinical isolates of C. neoformans obtained from AIDS patients with cryptococcal meningitis. No correlation between clinical outcome and MIC was observed for amphotericin B. In selected cases, the MFC seemed to be a better predictor of outcome than MIC. In this study, amphotericin B timed-kill curves appeared to show a correlation with clinical outcome of the 16 patients with AIDS-associated cryptococcal meningitis. These in vitro tests must be further evaluated in prospective studies to confirm their potential usefulness for guiding cryptococcal meningitis therapy.
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Affiliation(s)
- L Rodero
- Mycology Department, Instituto Nacional de Enfermedades Infecciosas, ANLIS: Dr. Carlos G. Malbrán, Buenos Aires, Argentina.
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38
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Abstract
Cryptococcus neoformans has become a major opportunistic fungal pathogen worldwide. Successful treatment of invasive disease with this fungus has used amphotericin B, flucytosine and various azoles. However, treatment failures continue to occur for a variety of reasons including direct antifungal drug resistance. Issues and mechanisms for antifungal drug resistance in Cryptococcus neoformans are reviewed. Furthermore, approaches and strategies for prevention and treatment of antifungal drug resistance are identified and these include host immune modulation, dose optimization, prophylaxis/empirical regimens, improved drug delivery systems such as lipid preparations of amphotericin B, surgery, combination antifungal treatments and development of new antifungal agents. Copyright 1999 Harcourt Publishers Ltd.
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Affiliation(s)
- John R. Perfect
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, USA
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39
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Mondon P, Petter R, Amalfitano G, Luzzati R, Concia E, Polacheck I, Kwon-Chung KJ. Heteroresistance to fluconazole and voriconazole in Cryptococcus neoformans. Antimicrob Agents Chemother 1999; 43:1856-61. [PMID: 10428902 PMCID: PMC89380 DOI: 10.1128/aac.43.8.1856] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/1998] [Accepted: 05/19/1999] [Indexed: 12/16/2022] Open
Abstract
Cryptococcus neoformans isolates that exhibited unusual patterns of resistance to fluconazole and voriconazole were isolated from seven isolates from two different geographical regions: one isolate from an Israeli non-AIDS patient and six serial isolates from an Italian AIDS patient who had suffered six recurrent episodes of cryptococcal meningitis. Each isolate produced cultures with heterogeneous compositions in which most of the cells were susceptible, but cells highly resistant to fluconazole (MICs, >/=64 microg/ml) were recovered at a variable frequency (7 x 10(-3) to 4.6 x 10(-2)). Evidence showed that this type of resistance is innate and is unrelated to drug exposure since the Israeli patient had never been treated with azoles or any other antimycotic agents. Analysis of clonal subpopulations of these two strains showed that they exhibited heterogeneous patterns of resistance. The number of subpopulations which grew on fluconazole or voriconazole agar declined progressively with increasing azole concentration without a sharp cutoff point. For the Italian serial isolates, the number of clonal populations resistant to fluconazole (64 microg/ml) and voriconazole (1 microg/ml) increased steadily, yielding the highest number for the isolate from the last episode. Attempts to purify a sensitive subpopulation failed, but clones highly resistant to fluconazole (100 microg/ml) and moderately resistant to voriconazole (1 microg/ml) always produced a homogeneous population of resistant cells. Upon maintenance on drug-free medium, however, the majority of the homogeneously resistant cells of these subclones lost their resistance and returned to the stable initial heteroresistant phenotype. The pattern of heteroresistance was not affected by the pH or osmolarity of the medium but was influenced by temperature. The resistance appeared to be suppressed at 35 degrees C and was completely abolished at 40 degrees C. Although heterogeneity in azole resistance among subpopulations of single isolates has been reported for Candida species, the transient changes in expression of resistance under different growth conditions reported here have not been observed in fungal pathogens.
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Affiliation(s)
- P Mondon
- Molecular Microbiology Section, Laboratory of Clinical Investigation, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892, USA
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40
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Tascini C, Vecchiarelli A, Preziosi R, Francisci D, Bistoni F, Baldelli F. Granulocyte-macrophage colony-stimulating factor and fluconazole enhance anti-cryptococcal activity of monocytes from AIDS patients. AIDS 1999; 13:49-55. [PMID: 10207544 DOI: 10.1097/00002030-199901140-00007] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To investigate the effect of human recombinant granulocyte-macrophage colony-stimulating factor (hrGM-CSF) and fluconazole on anti-cryptococcal activity of monocytes from AIDS patients and normal subjects. DESIGN The effect of GM-CSF and fluconazole on fungistatic and fungicidal activity of monocytes was studied in an in vitro system. METHODS Monocytes were treated in vitro with hrGM-CSF and fluconazole or either agent alone for 24 or 48 h, and fungistatic and fungicidal activity was evaluated in a colony-forming unit inhibition assay. CD11b/CD18 expression in monocytes was measured by flow cytometry analysis. Superoxide anion generation by peripheral blood monocytes was measured in the presence of pre-opsonized zymosan. RESULTS Defective antifungal capacity of monocytes from AIDS patients was observed. GM-CSF treatment of monocytes from AIDS patients increased fungistatic activity, and the combination of hrGM-CSF and fluconazole resulted in fungicidal activity. The mechanisms involved in the GM-CSF-mediated effect appeared to be mediated by (i) enhancement of phagocytic activity, (ii) increase of superoxide anion generation, and (iii) upregulation of CD11b/CD18 expression on the monocyte surface. CONCLUSIONS Our data highlight the effect of GM-CSF on anti-cryptococcal activity of human monocytes and show a synergistic effect of GM-CSF with fluconazole, suggesting a new therapeutic strategy in the treatment of cryptococcosis.
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Affiliation(s)
- C Tascini
- Department of Experimenta Medicine and Biochemical Sciences, University of Perugia, Italy
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41
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Pfaller M, Zhang J, Messer S, Tumberland M, Mbidde E, Jessup C, Ghannoum M. Molecular epidemiology and antifungal susceptibility of Cryptococcus neoformans isolates from Ugandan AIDS patients. Diagn Microbiol Infect Dis 1998; 32:191-9. [PMID: 9884835 DOI: 10.1016/s0732-8893(98)00095-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Little is known of the antifungal susceptibility patterns and molecular epidemiology of Cryptococcus neoformans from tropical regions. We studied 164 clinical isolates of C. neofomans from 120 Ugandan AIDS patients with cryptococcal meningitis by analyzing their electrophoretic karyotypes and antifungal susceptibility profiles. Computer-assisted analysis of karyotype patterns was performed to generate dendrograms. MICs of fluconazole and flucytosine were determined by reference methods. A total of 43 distinguishable DNA types were identified among the 164 isolates. Only 30 patients (25%) were infected with their own unique strain of c. neoformans, whereas 75% of the patients shared their infecting strain with at least one other patient. Among 17 patients with more than one CSF isolate of C. neoformans, sequential isolates were identical or highly related in 12 (71%) and were different in five patients (29%). The isolates were susceptible to both fluconazole and flucytosine and there were no instances in which a stepwise increase in either fluconazole or flucytosine MICs was observed among serial isolates. These findings suggest that the epidemiology of cryptococcal disease in AIDS patients from tropical regions may be somewhat different from that observed in more temperate climates.
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Affiliation(s)
- M Pfaller
- Department of Pathology, University of Iowa College of Medicine, Iowa City 52242, USA
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42
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Codd JE, Deasy P. Synergistic antifungal interaction between miconazole nitrate and chlorhexidine acetate. Int J Pharm 1998. [DOI: 10.1016/s0378-5173(98)00227-0] [Citation(s) in RCA: 8] [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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43
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Jessup CJ, Pfaller MA, Messer SA, Zhang J, Tumberland M, Mbidde EK, Ghannoum MA. Fluconazole susceptibility testing of Cryptococcus neoformans: comparison of two broth microdilution methods and clinical correlates among isolates from Ugandan AIDS patients. J Clin Microbiol 1998; 36:2874-6. [PMID: 9738036 PMCID: PMC105080 DOI: 10.1128/jcm.36.10.2874-2876.1998] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We compared the yeast nitrogen base (YNB) broth microdilution method with the National Committee for Clinical Laboratory Standards (NCCLS) M27-A microdilution reference method for measuring the in vitro susceptibility of Cryptococcus neoformans isolates to fluconazole. A total of 149 isolates of C. neoformans var. neoformans from Ugandan AIDS patients was tested by both methods. An overall agreement of 88% between the two microdilution methods was observed. All isolates grew well in both RPMI 1640 and YNB media, and MICs could be read after 48 h of incubation by both methods. The range of fluconazole MICs obtained with the YNB method was broader than that obtained with the NCCLS method. The extended range of MICs provided by the YNB method may be of clinical value, as it appears that the clinical outcome may be better among patients infected with strains inhibited by lower concentrations of fluconazole as determined by the YNB method. The YNB method appears to be a viable option for testing C. neoformans against fluconazole.
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Affiliation(s)
- C J Jessup
- Mycology Reference Laboratory, Center for Medical Mycology, Department of Dermatology, Case Western Reserve University and University Hospitals of Cleveland, Ohio, USA
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44
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Mukherjee J, Kozel TR, Casadevall A. Monoclonal Antibodies Reveal Additional Epitopes of Serotype D Cryptococcus neoformans Capsular Glucuronoxylomannan that Elicit Protective Antibodies. THE JOURNAL OF IMMUNOLOGY 1998. [DOI: 10.4049/jimmunol.161.7.3557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Abstract
Epitope specificity and isotype influence mAb efficacy against Cryptococcus neoformans; however, the relative contribution of each attribute is poorly understood. To date, only mAbs that recognize two epitopes of capsular glucuronoxylomannan (GXM), defined by the IgG1 mAbs 2H1 and E1, consistently mediate protection against C. neoformans. The role of epitope specificity was further examined using six additional IgG1 mAbs and serotype D C. neoformans ATCC 24067. mAbs 3C2, 439, and 471 recognize the 2H1 epitope, whereas mAbs 339, 1255, and 302 recognize two separate epitopes. mAbs 3C2, 439, and 471 competed for GXM with the IgA mAb 18G9, a 2H1 mAb family member, whereas mAbs 302, 339, and 1255 did not. Each mAb bound GXM similarly, as determined by agglutination, direct Ag binding, Ag inhibition, and indirect capsular immunofluorescence assays. mAb apparent affinity constants for GXM ranged from 5 to 26 × 107 M−1 with mAb 1255 > 3C2 > 339 > 439 > 471 > 302. Each mAb significantly prolonged survival (p < 0.05); the average survival times of control and mice passively immunized with mAbs 3C2, 302, 339, 439, 471, and 1255 were 10.8, 36.6, 33, 25.5, 24.9, 17, and 22.6 days, respectively. Although each mAb enhanced J774.16 cell fungicidal activity, differences were observed in the ability of each mAb to facilitate attachment and ingestion of cryptococci. These results indicate 1) two additional epitope specificities associated with mAb efficacy, 2) differences in opsonic and protective efficacy for IgG1 anti-GXM mAbs, 3) an association between affinity and protective efficacy, and 4) additional support for association between an annular indirect capsular immunofluorescence pattern and mAb efficacy.
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Affiliation(s)
- Jean Mukherjee
- *Division of Infectious Diseases, Department of Medicine, and
| | - Thomas R. Kozel
- ‡Department of Microbiology, University of Nevada School of Medicine, Reno, NV 89557
| | - Arturo Casadevall
- *Division of Infectious Diseases, Department of Medicine, and
- †Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461; and
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45
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Kirkpatrick WR, McAtee RK, Revankar SG, Fothergill AW, McCarthy DI, Rinaldi MG, Patterson TF. Comparative evaluation of National Committee for Clinical Laboratory Standards broth macrodilution and agar dilution screening methods for testing fluconazole susceptibility of Cryptococcus neoformans. J Clin Microbiol 1998; 36:1330-2. [PMID: 9574699 PMCID: PMC104822 DOI: 10.1128/jcm.36.5.1330-1332.1998] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/1997] [Accepted: 02/06/1998] [Indexed: 02/07/2023] Open
Abstract
A simple screening method for fluconazole susceptibility of Cryptococcus neoformans using 2% dextrose Sabouraud dextrose agar (SabDex) with fluconazole was compared to the National Committee for Clinical Laboratory Standards (NCCLS) broth macrodilution method. By this method, fluconazole-susceptible C. neoformans isolates are significantly smaller on medium with fluconazole than on fluconazole-free medium. Isolates with decreased susceptibility have normal-size colonies on medium containing fluconazole. The 48-h NCCLS broth macrodilution MICs (NCCLS MICs) for isolates with normal-size colonies on 8- or 16-microg/ml fluconazole plates were predicted to be > or =8 or > or =16 microg/ml, respectively. On medium with 16 microg of fluconazole per ml, all strains (84 of 84) for which the NCCLS MICs were <16 microg/ml were correctly predicted, as were all isolates (7 of 7) for which the MICs were > or =16 microg/ml. Agar dilution appears to be an effective screening method for fluconazole resistance in C. neoformans.
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Affiliation(s)
- W R Kirkpatrick
- Department of Medicine, University of Texas Health Science Center at San Antonio, 78284-7881, USA
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46
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White TC, Marr KA, Bowden RA. Clinical, cellular, and molecular factors that contribute to antifungal drug resistance. Clin Microbiol Rev 1998; 11:382-402. [PMID: 9564569 PMCID: PMC106838 DOI: 10.1128/cmr.11.2.382] [Citation(s) in RCA: 896] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In the past decade, the frequency of diagnosed fungal infections has risen sharply due to several factors, including the increase in the number of immunosuppressed patients resulting from the AIDS epidemic and treatments during and after organ and bone marrow transplants. Linked with the increase in fungal infections is a recent increase in the frequency with which these infections are recalcitrant to standard antifungal therapy. This review summarizes the factors that contribute to antifungal drug resistance on three levels: (i) clinical factors that result in the inability to successfully treat refractory disease; (ii) cellular factors associated with a resistant fungal strain; and (iii) molecular factors that are ultimately responsible for the resistance phenotype in the cell. Many of the clinical factors that contribute to resistance are associated with the immune status of the patient, with the pharmacology of the drugs, or with the degree or type of fungal infection present. At a cellular level, antifungal drug resistance can be the result of replacement of a susceptible strain with a more resistant strain or species or the alteration of an endogenous strain (by mutation or gene expression) to a resistant phenotype. The molecular mechanisms of resistance that have been identified to date in Candida albicans include overexpression of two types of efflux pumps, overexpression or mutation of the target enzyme, and alteration of other enzymes in the same biosynthetic pathway as the target enzyme. Since the study of antifungal drug resistance is relatively new, other factors that may also contribute to resistance are discussed.
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Affiliation(s)
- T C White
- Department of Pathobiology, School of Public Health and Community Medicine, University of Washington, Seattle Biomedical Research Institute, Washington, USA.
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47
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Abstract
The availability of standard guidelines (NCCLS M27 document) for antifungal susceptibility testing has facilitated the establishment of tentative interpretive breakpoints for fluconazole and itraconazole by the NCCLS. Based on correlations of MIC values with the outcomes of patients with mostly Candida infections, fluconazole MICs of > or = 64 and itraconazole MICs of > or = 1.0 microgram/mL are considered resistant. Fluconazole MICs of 16 to 32 micrograms/mL and itraconazole MICs of 0.2 to 0.5 microgram/mL were categorized as "susceptible dependent upon dose" (S-DD), that is, clinical response may be obtained with increased doses. Susceptible breakpoints for fluconazole and itraconazole correspond to < or = 8 and < or = 0.12 microgram/mL, respectively. For flucytosine, resistant and susceptible breakpoints for Candida were set at > or = 32 micrograms/mL and 4 micrograms/mL, respectively, based on historical data and the drug's pharmacokinetics for Candida. Although no breakpoints have been established for amphotericin B, clinical failure has been associated with MICs > 1.0 microgram/mL.
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Affiliation(s)
- A Espinel-Ingroff
- Department of Internal Medicine, Medical College of Virginia/Virginia Commonwealth University, Richmond, USA
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48
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Alves SH, Lopes JO, Costa JM, Klock C. Development of secondary resistance to fluconazole in Cryptococcus neoformans isolated from a patient with AIDS. Rev Inst Med Trop Sao Paulo 1997; 39:359-61. [PMID: 9674289 DOI: 10.1590/s0036-46651997000600010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Cryptococcus neoformans is the fifth most common opportunistic agent of infection in patients with AIDS in the USA, exceeded only by Candida species, Pneumocystis carinii, cytomegalovirus and Mycobacterium avium1, 2, 6, 10, 11. In Brazil is the sixth, exceeded by Candida species, P. carinii, Mycobacterium species, Toxoplasma gondii, and herpes simplex virus (AIDS, Boletim Epidemiológico, set/nov 96, Ministério da Saúde, Brasil). During 30 years, the treatment of C. neoformans meningitis was based on the use of amphotericin B with or without flucytosine13. Nowadays, with the immunodepression caused by human immunodeficiency virus (HIV) infection and the availability of new antifungal drugs as the triazoles, the concept related to cure and relapses of cryptococcosis has been altered7, 20. Patients are treated with amphotericin B with or without flucytosine as initial therapy, but maintenance therapy is always necessary in AIDS patients with C. neoformans infections
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Affiliation(s)
- S H Alves
- Serviço de Micologia, Hospital Universitário, Universidade Federal de Santa Maria, Rio Grande do Sul, Brasil
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49
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Alexander BD, Perfect JR. Antifungal resistance trends towards the year 2000. Implications for therapy and new approaches. Drugs 1997; 54:657-78. [PMID: 9360056 DOI: 10.2165/00003495-199754050-00002] [Citation(s) in RCA: 116] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Medical advances have led to increased numbers of immunocompromised patients living longer. Coinciding with this increase in the immunocompromised patient population is an increase in the number of clinically significant fungal infections. Unfortunately, widespread use of the limited numbers of antifungal agents to treat these infections has led to the development of drug resistance. Thus, in an attempt to sort out the mechanisms of resistance for each of the systemically useful antifungal agents, a comprehensive review of the literature has been carried out. The most common mechanisms for the development of resistance involve changes in the enzymatic pathways which serve as the drug targets. For instance, changes in enzymes responsible for the biosynthesis of ergosterol, the target of azole activity, lead to azole resistance. Another common mechanism used by fungi to avoid drug toxicity includes reduced intracellular accumulation of the drug through both decreased permeability and energy-dependent efflux pumps. Using our current understanding of the mechanisms of drug resistance as a template, several strategies to overcome resistance have been identified. These include improvement of host immune function, the use of adjuvant surgery, the development of new drug delivery systems for currently available drugs and the development of new classes of antifungal agents. Also, clinical trials to establish appropriate drug doses and duration of therapy are needed, as well as the benefits of antifungal prophylaxis explored and the use of combination therapies entertained. The war against drug resistant fungi has been identified as we approach the year 2000. With careful and cogent investigations, we do have the tools to fight back against these opportunists. Of all the strategies reviewed, however, in our opinion, the development of new antifungal drugs is likely to have the most significant future impact on our management of drug resistance in fungal infections.
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Affiliation(s)
- B D Alexander
- Division of Infectious Diseases, Duke University Medical Center, Durham, North Carolina, USA
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Poonwan N, Mikami Y, Poosuwan S, Boon-Long J, Mekha N, Kusum M, Yazawa K, Tanaka R, Nishimura K, Konyama K. Serotyping of Cryptococcus neoformans strains isolated from clinical specimens in Thailand and their susceptibility to various antifungal agents. Eur J Epidemiol 1997; 13:335-40. [PMID: 9258534 DOI: 10.1023/a:1007376917836] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
One hundred and thirty-nine strains of Cryptococcus neoformans were isolated in Thailand from clinical specimens including 97 AIDS patients: 67 from Northern, 48 from Central, 17 from Northeastern and 7 from Southern regional hospitals. Six out of the 139 strains were serotype B and the remaining 133 were A. There was no correlation between serotypes and regional distribution. To our knowledge, this is the first report of serotyping studies on C. neoformans in Thailand. Studies on random amplified polymorphic DNA (RAPD) analysis showed that this method is useful for the differentiation of C. neoformans var. gattii (serotypes B and C) and C. neoformans var. neoformans (serotypes A and D). They also indicated that Thai isolates of C. neoformans var. gattii (serotype B) were a homogeneous group on the basis of their genotypes. Antifungal susceptibility tests using 5 antifungal agents including amphotericin B, fluconazole, flucytosine, itraconazole and micronazole against 50 selected strains of C. neoformans showed that they were sensitive to all of the antifungal agents tested except for one strain that was resistant to flucytosine.
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Affiliation(s)
- N Poonwan
- Department of Medical Sciences, National Institute of Health, Nonthaburi, Thailand
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