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Carvajal SK, Melendres J, Escandón P, Firacative C. Reduced Susceptibility to Azoles in Cryptococcus gattii Correlates with the Substitution R258L in a Substrate Recognition Site of the Lanosterol 14-α-Demethylase. Microbiol Spectr 2023; 11:e0140323. [PMID: 37341584 PMCID: PMC10434158 DOI: 10.1128/spectrum.01403-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 06/01/2023] [Indexed: 06/22/2023] Open
Abstract
Cryptococcus neoformans and Cryptococcus gattii cause cryptococcosis, a life-threatening fungal infection affecting mostly immunocompromised patients. In fact, cryptococcal meningitis accounts for about 19% of AIDS-related deaths in the world. Because of long-term azole therapies to treat this mycosis, resistance to fluconazole leading to treatment failure and poor prognosis has long been reported for both fungal species. Among the mechanisms implicated in resistance to azoles, mutations in the ERG11 gene, encoding the azole target enzyme lanosterol 14-α-demethylase, have been described. This study aimed to establish the amino acid composition of ERG11 of Colombian clinical isolates of C. neoformans and C. gattii and to correlate any possible substitution with the in vitro susceptibility profile of the isolates to fluconazole, voriconazole, and itraconazole. Antifungal susceptibility testing results showed that C. gattii isolates are less susceptible to azoles than C. neoformans isolates, which could correlate with differences in the amino acid composition and structure of ERG11 of each species. In addition, in a C. gattii isolate with high MICs for fluconazole (64 μg/mL) and voriconazole (1 μg/mL), a G973T mutation resulting in the substitution R258L, located in substrate recognition site 3 of ERG11, was identified. This finding suggests the association of the newly reported substitution with the azole resistance phenotype in C. gattii. Further investigations are needed to determine the exact role that R258L plays in the decreased susceptibility to fluconazole and voriconazole, as well as to determine the participation of additional mechanisms of resistance to azole drugs. IMPORTANCE The fungal species Cryptococcus neoformans and C. gattii are human pathogens for which drug resistance or other treatment and management challenges exist. Here, we report differential susceptibility to azoles among both species, with some isolates displaying resistant phenotypes. Azoles are among the most commonly used drugs to treat cryptococcal infections. Our findings underscore the necessity of testing antifungal susceptibility in the clinical setting in order to assist patient management and beneficial outcomes. In addition, we report an amino acid change in the sequence of the target protein of azoles, which suggests that this change might be implicated in resistance to these drugs. Identifying and understanding possible mechanisms that affect drug affinity will eventually aid the design of new drugs that overcome the global growing concern of antifungal resistance.
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Affiliation(s)
| | - Javier Melendres
- Studies in Translational Microbiology and Emerging Diseases (MICROS) Research Group, School of Medicine and Health Sciences, Universidad del Rosario, Bogotá, Colombia
| | - Patricia Escandón
- Group of Microbiology, Instituto Nacional de Salud, Bogotá, Colombia
| | - Carolina Firacative
- Studies in Translational Microbiology and Emerging Diseases (MICROS) Research Group, School of Medicine and Health Sciences, Universidad del Rosario, Bogotá, Colombia
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Bertout S, Laroche L, Roger F, Krasteva D, Drakulovski P, Bellet V. Fluconazole Resistance and Virulence in In Vitro Induced-Fluconazole Resistant Strains and in Clinical Fluconazole Resistant Strain of Cryptococcus deuterogattii. Pathogens 2023; 12:758. [PMID: 37375448 DOI: 10.3390/pathogens12060758] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 05/19/2023] [Accepted: 05/23/2023] [Indexed: 06/29/2023] Open
Abstract
Neuromeningeal cryptococcosis is a life-threatening infection of the central nervous system, caused by encapsulated yeast belonging to the Cryptococcus neoformans and Cryptococcus gattii species complexes. Recent data showed that virulence and antifungal resistance are variable for yeasts belonging to the C. gattii species complex. There is an increase in resistance to fluconazole for yeasts of the C. gattii species complex and the virulence is variable according to the genotype. In the present study, (i) we explored and compared the mechanisms of resistance to fluconazole between C. deuterogattii clinically resistant strains and induced fluconazole-resistant strains by exposure to fluconazole in vitro, and (ii) we studied their virulence in the Galleria mellonella study model. We demonstrated that the fluconazole resistance mechanisms involved were different between clinically resistant strains and induced resistant strains. We also demonstrated that fluconazole-induced resistant strains are less virulent when compared to the original susceptible strains. On the contrary, the clinically resistant strain tested maintains its virulence compared to fluconazole-susceptible strains of the same sequence type.
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Affiliation(s)
- Sébastien Bertout
- Laboratoire de Parasitologie et Mycologie Médicale, TransVIHMI, University of Montpellier, INSERM, IRD, 15 Avenue Charles Flahaut, 34093 Montpellier, France
| | - Laetitia Laroche
- Laboratoire de Biologie Médicale, Hôpital Lozère, 48000 Mende, France
| | - Frédéric Roger
- Laboratoire de Parasitologie et Mycologie Médicale, TransVIHMI, University of Montpellier, INSERM, IRD, 15 Avenue Charles Flahaut, 34093 Montpellier, France
| | - Donika Krasteva
- Laboratoire de Parasitologie et Mycologie Médicale, TransVIHMI, University of Montpellier, INSERM, IRD, 15 Avenue Charles Flahaut, 34093 Montpellier, France
| | - Pascal Drakulovski
- Laboratoire de Parasitologie et Mycologie Médicale, TransVIHMI, University of Montpellier, INSERM, IRD, 15 Avenue Charles Flahaut, 34093 Montpellier, France
| | - Virginie Bellet
- Laboratoire de Parasitologie et Mycologie Médicale, TransVIHMI, University of Montpellier, INSERM, IRD, 15 Avenue Charles Flahaut, 34093 Montpellier, France
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Howard-Jones AR, Sparks R, Pham D, Halliday C, Beardsley J, Chen SCA. Pulmonary Cryptococcosis. J Fungi (Basel) 2022; 8:1156. [PMID: 36354923 PMCID: PMC9696922 DOI: 10.3390/jof8111156] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 10/26/2022] [Accepted: 10/29/2022] [Indexed: 07/25/2023] Open
Abstract
Pulmonary cryptococcosis describes an invasive lung mycosis caused by Cryptococcus neoformans or Cryptococcus gattii complex. It is often a high-consequence disease in both immunocompromised and immunocompetent populations, and may be misdiagnosed as pulmonary malignancy, leading to a delay in therapy. Epidemiology follows that of cryptococcal meningoencephalitis, with C. gattii infection more common in certain geographic regions. Diagnostic tools include histopathology, microscopy and culture, and the detection of cryptococcal polysaccharide antigen or Cryptococcus-derived nucleic acids. All patients with lung cryptococcosis should have a lumbar puncture and cerebral imaging to exclude central nervous system disease. Radiology is key, both as an adjunct to laboratory testing and as the initial means of detection in asymptomatic patients or those with non-specific symptoms. Pulmonary cryptococcomas (single or multiple) may also be associated with disseminated disease and/or cryptococcal meningitis, requiring prolonged treatment regimens. Optimal management for severe disease requires extended induction (amphotericin B and flucytosine) and consolidation therapy (fluconazole) with close clinical monitoring. Susceptibility testing is of value for epidemiology and in regions where relatively high minimum inhibitory concentrations to azoles (particularly fluconazole) have been noted. Novel diagnostic tools and therapeutic agents promise to improve the detection and treatment of cryptococcosis, particularly in low-income settings where the disease burden is high.
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Affiliation(s)
- Annaleise R. Howard-Jones
- Centre for Infectious Diseases & Microbiology Laboratory Services, New South Wales Health Pathology—Institute of Clinical Pathology & Medical Research, Westmead Hospital, Westmead, NSW 2145, Australia
- Faculty of Medicine and Health, University of Sydney, Camperdown, NSW 2145, Australia
- Sydney Institute for Infectious Diseases, The University of Sydney, Sydney, NSW 2006, Australia
| | - Rebecca Sparks
- Centre for Infectious Diseases & Microbiology Laboratory Services, New South Wales Health Pathology—Institute of Clinical Pathology & Medical Research, Westmead Hospital, Westmead, NSW 2145, Australia
| | - David Pham
- Centre for Infectious Diseases & Microbiology Laboratory Services, New South Wales Health Pathology—Institute of Clinical Pathology & Medical Research, Westmead Hospital, Westmead, NSW 2145, Australia
| | - Catriona Halliday
- Centre for Infectious Diseases & Microbiology Laboratory Services, New South Wales Health Pathology—Institute of Clinical Pathology & Medical Research, Westmead Hospital, Westmead, NSW 2145, Australia
| | - Justin Beardsley
- Faculty of Medicine and Health, University of Sydney, Camperdown, NSW 2145, Australia
- Sydney Institute for Infectious Diseases, The University of Sydney, Sydney, NSW 2006, Australia
- Westmead Institute for Medical Research, Westmead, NSW 2145, Australia
| | - Sharon C.-A. Chen
- Centre for Infectious Diseases & Microbiology Laboratory Services, New South Wales Health Pathology—Institute of Clinical Pathology & Medical Research, Westmead Hospital, Westmead, NSW 2145, Australia
- Faculty of Medicine and Health, University of Sydney, Camperdown, NSW 2145, Australia
- Sydney Institute for Infectious Diseases, The University of Sydney, Sydney, NSW 2006, Australia
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Lahiri S, Chandrashekar N. Advanced approach for antifungal susceptibility and characterization of resistance properties in clinical and environmental isolates of Cryptococcus species complex. INFECTIOUS MEDICINE 2022; 1:147-153. [PMID: 38077629 PMCID: PMC10699700 DOI: 10.1016/j.imj.2022.08.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 07/17/2022] [Accepted: 08/23/2022] [Indexed: 09/07/2024]
Abstract
BACKGROUND Meningitis due to Cryptococcus neoformans/gattii is a fatal infection affecting immunocompromised population worldwide. Amphotericin B (AmB), fluconazole (FLC) and 5-flucytosine are the drugs of choice to treat the infection. We studied antifungal susceptibility pattern of clinical and environmental cryptococcal species using newer approach and analyze their resistant characteristics. METHODS Eighty clinical (54 C. neoformans and 26 C. gattii) and 18 environmental (14 C. neoformans and 4 C. gattii) isolates were subjected to antifungal susceptibility testing by automated (VITEK2C) method. Minimum inhibitory concentrations (MIC) were analyzed statistically. Genomic DNA of FLC resistant isolates was extracted and amplified to detect presence of CnAFR1 gene. RESULTS C. neoformans showed 1.85% and 21.4% AmB resistance, and 1.85% and 28.5% FLC- resistance, whereas C. gattii showed 25% and 50% FLC-resistance among clinical and environmental isolates respectively. MIC values were significantly (p < 0.05) different for the isolates from 2 sources. CnAFR1 gene sequence analysis revealed phylogenetic relationship among the resistant isolates. CONCLUSIONS This pioneering study provides an insight into the sensitivity patterns of clinical and environmental cryptococcal isolates from south India. The recent emergence of AmB-resistance may transpire as a challenge for the clinicians. As the clinical and environmental isolates are phylogenetically evolved from CnAFR1 gene of Filobasidiella neoformans, the resistance is most probably an inherent attribute. This study emphasizes the need for speciation and antifungal susceptibility testing of cryptococcal isolates from clinical sources to institute appropriate antifungal therapy and to reduce the mortality and morbidity.
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Affiliation(s)
- Shayanki Lahiri
- Department of Neuromicrobiology, National Institute of Mental Health and Neuro Sciences, Bangalore, Karnataka, India
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, USA
| | - Nagarathna Chandrashekar
- Department of Neuromicrobiology, National Institute of Mental Health and Neuro Sciences, Bangalore, Karnataka, India
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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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Abstract
Cryptococcosis is a disease caused by the pathogenic fungi Cryptococcus neoformans and Cryptococcus gattii, both environmental fungi that cause severe pneumonia and may even lead to cryptococcal meningoencephalitis. Although C. neoformans affects more fragile individuals, such as immunocompromised hosts through opportunistic infections, C. gattii causes a serious indiscriminate primary infection in immunocompetent individuals. Typically seen in tropical and subtropical environments, C. gattii has increased its endemic area over recent years, largely due to climatic factors that favor contagion in warmer climates. It is important to point out that not only C. gattii, but the Cryptococcus species complex produces a polysaccharidic capsule with immunomodulatory properties, enabling the pathogenic species of Cryptococccus to subvert the host immune response during the establishment of cryptococcosis, facilitating its dissemination in the infected organism. C. gattii causes a more severe and difficult-to-treat infection, with few antifungals eliciting an effective response during chronic treatment. Much of the immunopathology of this cryptococcosis is still poorly understood, with most studies focusing on cryptococcosis caused by the species C. neoformans. C. gattii became more important in the epidemiological scenario with the outbreaks in the Pacific Northwest of the United States, which resulted in phylogenetic studies of the virulent variant responsible for the severe infection in the region. Since then, the study of cryptococcosis caused by C. gattii has helped researchers understand the immunopathological aspects of different variants of this pathogen.
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Akapo OO, Macnar JM, Kryś JD, Syed PR, Syed K, Gront D. In Silico Structural Modeling and Analysis of Interactions of Tremellomycetes Cytochrome P450 Monooxygenases CYP51s with Substrates and Azoles. Int J Mol Sci 2021; 22:7811. [PMID: 34360577 PMCID: PMC8346148 DOI: 10.3390/ijms22157811] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 05/21/2021] [Accepted: 05/25/2021] [Indexed: 11/16/2022] Open
Abstract
Cytochrome P450 monooxygenase CYP51 (sterol 14α-demethylase) is a well-known target of the azole drug fluconazole for treating cryptococcosis, a life-threatening fungal infection in immune-compromised patients in poor countries. Studies indicate that mutations in CYP51 confer fluconazole resistance on cryptococcal species. Despite the importance of CYP51 in these species, few studies on the structural analysis of CYP51 and its interactions with different azole drugs have been reported. We therefore performed in silico structural analysis of 11 CYP51s from cryptococcal species and other Tremellomycetes. Interactions of 11 CYP51s with nine ligands (three substrates and six azoles) performed by Rosetta docking using 10,000 combinations for each of the CYP51-ligand complex (11 CYP51s × 9 ligands = 99 complexes) and hierarchical agglomerative clustering were used for selecting the complexes. A web application for visualization of CYP51s' interactions with ligands was developed (http://bioshell.pl/azoledocking/). The study results indicated that Tremellomycetes CYP51s have a high preference for itraconazole, corroborating the in vitro effectiveness of itraconazole compared to fluconazole. Amino acids interacting with different ligands were found to be conserved across CYP51s, indicating that the procedure employed in this study is accurate and can be automated for studying P450-ligand interactions to cater for the growing number of P450s.
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Affiliation(s)
- Olufunmilayo Olukemi Akapo
- Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa 3886, South Africa;
| | - Joanna M. Macnar
- College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, Stefana Banacha 2C, 02-097 Warsaw, Poland;
- Biological and Chemical Research Center, Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland;
| | - Justyna D. Kryś
- Biological and Chemical Research Center, Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland;
| | - Puleng Rosinah Syed
- Department of Pharmaceutical Chemistry, College of Health Sciences, University of KwaZulu-Natal, Durban 4000, South Africa;
| | - Khajamohiddin Syed
- Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa 3886, South Africa;
| | - Dominik Gront
- Biological and Chemical Research Center, Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland;
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Pharkjaksu S, Chongtrakool P, Chayakulkeeree M, Mitrpant C, Angkasekwinai P, Bennett JE, Kwon-Chung KJ, Ngamskulrungroj P. Cryptococcus neoformans/gattii Species Complexes from Pre-HIV Pandemic Era Contain Unusually High Rate of Non-Wild-Type Isolates for Amphotericin B. Infect Drug Resist 2020; 13:673-681. [PMID: 32161475 PMCID: PMC7049752 DOI: 10.2147/idr.s235473] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 02/11/2020] [Indexed: 12/14/2022] Open
Abstract
Introduction The Cryptococcus neoformans/gattii species complexes are a leading cause of fatality among HIV-infected patients. Despite the unavailability of clinical breakpoints (CBPs) for antifungal agents, epidemiological cutoff values (ECVs) were recently proposed, and non-wild-type isolates for polyenes and azoles are being increasingly reported. However, the distributions of the susceptibility patterns for pre-HIV-era isolates have not been studied. Methods We determined the in vitro antifungal susceptibility patterns of 233 Cryptococcus isolates, collected at the National Institutes of Health, USA, in pre-HIV pandemic era, to study minimum inhibitory concentrations (MICs) to the important drugs for cryptococcosis and to compare the results with strain genotypes. Amphotericin B susceptibility was compared to published ECV of C. neoformans. Results The 233 Cryptococcus strains consisted of 89.7% C. neoformans species complex and 10.3% C. gattii species complex. Most were from clinical sources (189, 81.1%), and the major molecular type was VNI (146, 62.7%). The highest geometric mean (GM) was observed for fluconazole (GM = 0.96 µg/mL) while the lowest was for itraconazole (GM = 0.10 µg/mL). MICs to fluconazole in C. gattii species complex were significantly higher than C. neoformans species complex (p < 0.001). Moreover, C. neoformans/VNI strains showed significantly higher MICs than others such as C. neoformans/VNII to fluconazole (p < 0.0001) and C. deneoformans/VNIV to amphotericin B (p = 0.022) and fluconazole (p = 0.008). In our collection of 167 clinical C. neoformans species complex strains, 85 (50.9%), 24 (14.4%), and 3 (1.8%) strains had an amphotericin B (AMB)-MIC of 1, 2, and 4 µg/mL, respectively. The high percentage (66.9%, 79/118 strains) of non-wild-type clinical C. neoformans VNI strains, using an AMB-ECV of 0.5 µg/mL, was found. Moreover, 25 of 28 (89.3%) C. neoformans VNI strains from environmental and veterinary sources also had AMB-MICs above 0.5 µg/mL. In general, there was no significant difference in GM AMB-MIC of the clinical strains isolated from patients with (35 patients) and without (78 patients) prior AMB treatment (0.85 vs 0.76; p = 0.624). GM MIC of the environmental strains was not significantly different from that of the prior AMB-treatment strains (0.98 vs 0.76, p = 0.159) and the post-AMB-treatment strains (0.98 vs 0.85, p = 0.488). Conclusion The high rate of non-wild-type among these otherwise naive isolates to amphotericin B is unexpected. Confirmation with more strains from a later era is needed.
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Affiliation(s)
- Sujiraphong Pharkjaksu
- Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Piriyaporn Chongtrakool
- Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Methee Chayakulkeeree
- Division of Infectious Diseases and Tropical Medicine, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Chalermchai Mitrpant
- Department of Biochemistry, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Pornpimon Angkasekwinai
- Department of Medical Technology, Faculty of Allied Health Sciences, Thammasat University, Pathumthani, Thailand
| | - John E Bennett
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Kyung J Kwon-Chung
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Popchai Ngamskulrungroj
- Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
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Diaz JH. The Disease Ecology, Epidemiology, Clinical Manifestations, and Management of Emerging Cryptococcus gattii Complex Infections. Wilderness Environ Med 2019; 31:101-109. [PMID: 31813737 DOI: 10.1016/j.wem.2019.10.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 09/18/2019] [Accepted: 10/09/2019] [Indexed: 01/12/2023]
Abstract
Cryptococcus neoformans, a soil-dwelling fungus found worldwide, can cause cryptococcosis, an opportunistic fungal infection of the lungs and central nervous system. One former member of the C neoformans complex, Cryptococcus gattii, has caused meningitis in immunosuppressed and immunocompetent persons in endemic regions in Africa and Asia. Between 1999 and 2004, C gattii caused outbreaks of human cryptococcosis in unexpected, nonendemic, nontropical regions on Vancouver Island, Canada, and throughout the US Pacific Northwest and California. C gattii was recognized as an emerging species with several genotypes and a unique environmental relationship with trees that are often encountered in the wilderness and in landscaped parks. Because C gattii infections have a high case-fatality rate, wilderness medicine clinicians should be aware of this emerging pathogen, its disease ecology and risk factors, its expanding geographic distribution in North America, and its ability to cause fatal disease in both immunosuppressed and immunocompetent persons.
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Affiliation(s)
- James H Diaz
- Environmental and Occupational Health Sciences, School of Public Health, Louisiana State University Health Sciences Center (LSUHSC), New Orleans, LA; School of Medicine, Louisiana State University Health Sciences Center (LSUHSC), New Orleans, LA.
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10
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Beardsley J, Sorrell TC, Chen SCA. Central Nervous System Cryptococcal Infections in Non-HIV Infected Patients. J Fungi (Basel) 2019; 5:jof5030071. [PMID: 31382367 PMCID: PMC6787755 DOI: 10.3390/jof5030071] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 07/22/2019] [Accepted: 07/29/2019] [Indexed: 12/27/2022] Open
Abstract
Central nervous system (CNS) cryptococcosis in non-HIV infected patients affects solid organ transplant (SOT) recipients, patients with malignancy, rheumatic disorders, other immunosuppressive conditions and immunocompetent hosts. More recently described risks include the use of newer biologicals and recreational intravenous drug use. Disease is caused by Cryptococcus neoformans and Cryptococcus gattii species complex; C. gattii is endemic in several geographic regions and has caused outbreaks in North America. Major virulence determinants are the polysaccharide capsule, melanin and several ‘invasins’. Cryptococcal plb1, laccase and urease are essential for dissemination from lung to CNS and crossing the blood–brain barrier. Meningo-encephalitis is common but intracerebral infection or hydrocephalus also occur, and are relatively frequent in C. gattii infection. Complications include neurologic deficits, raised intracranial pressure (ICP) and disseminated disease. Diagnosis relies on culture, phenotypic identification methods, and cryptococcal antigen detection. Molecular methods can assist. Preferred induction antifungal therapy is a lipid amphotericin B formulation (amphotericin B deoxycholate may be used in non-transplant patients) plus 5-flucytosine for 2–6 weeks depending on host type followed by consolidation/maintenance therapy with fluconazole for 12 months or longer. Control of raised ICP is essential. Clinicians should be vigilant for immune reconstitution inflammatory syndrome.
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Affiliation(s)
- Justin Beardsley
- Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, Sydney 2145, Australia
| | - Tania C Sorrell
- Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, Sydney 2145, Australia
- Westmead Institute for Medical Research, Westmead, Sydney 2145, Australia
| | - Sharon C-A Chen
- Centre for Infectious Diseases and Microbiology Laboratory Services, Institute of Clinical Pathology and Medical Research, NSW Health Pathology, Westmead Hospital and the Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, Sydney 2145, Australia.
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Hori Y, Shibuya K. Role of FKS Gene in the Susceptibility of Pathogenic Fungi to Echinocandins. Med Mycol J 2018; 59:E31-E40. [PMID: 29848909 DOI: 10.3314/mmj.18.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Echinocandins are antifungal agents that specifically inhibit the biosynthesis of 1,3-β-D-glucan, a major structural component of fungal cell walls. Echinocandins are recommended as first-line or alternative/salvage therapy for candidiasis and aspergillosis in antifungal guidelines of various countries. Resistance to echinocandins has been reported in recent years. The mechanism of echinocandin resistance involves amino acid substitutions in hot spot regions of the FKS gene product, the catalytic subunit of 1,3-β-D-glucan synthase. This resistance mechanism contributes to not only acquired resistance in Candida spp., but also inherent resistance in some pathogenic fungi. An understanding of the echinocandin resistance mechanism is important to develop both effective diagnosis and treatment options for echinocandin-resistant fungal diseases.
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Affiliation(s)
- Yasuhiro Hori
- Department of Surgical Pathology, Toho University School of Medicine
| | - Kazutoshi Shibuya
- Department of Surgical Pathology, Toho University School of Medicine
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Kassi FK, Bellet V, Drakulovski P, Krasteva D, Roger F, Valérie BTA, Aboubakar T, Doumbia A, Kouakou GA, Delaporte E, Reynes J, Yavo W, Menan HIE, Bertout S. Comparative typing analyses of clinical and environmental strains of the Cryptococcus neoformans/Cryptococcus gattii species complex from Ivory Coast. J Med Microbiol 2017; 67:87-96. [PMID: 29214970 DOI: 10.1099/jmm.0.000654] [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] [Indexed: 01/09/2023] Open
Abstract
PURPOSE The aim of this study was to assess the biotope of the Cryptococcus neoformans/Cryptococcus gattii species complex from Ivory Coast, and clarify the possible epidemiological relationship between environmental and clinical strains. METHODOLOGY Samples from Eucalyptus camaldulensis (n=136), Mangifera indica (n=13) and pigeon droppings (n=518) were collected from different sites close to the living environment of Ivorian HIV patients with cryptococcosis (n=10, 50 clinical strains). Clinical and environmental strains were characterized by molecular serotyping and genotyping [RFLP analysis of the URA5 gene, (GACA)4, (GTG)5 and M13 PCR fingerprinting] and compared.Results/Key findings. Environmental strains were recovered only from the pigeon droppings. In vitro susceptibility profiles showed that all strains were susceptible to fluconazole, flucytosine and amphotericin B. All environmental strains consisted of C. neoformans (A, AFLP1/VNI), whereas clinical strains included C. neoformans (A, AFLP1/VNI), C. neoformans x Cryptococcus deneoformans hybrids (AD, AFLP3/VNIII) and Cryptococcus deuterogattii (B, AFLP6/VGII). Two patients were co-infected with both C. neoformans and C. neoformans x C. deneoformans hybrids. We noticed a low genetic diversity among the environmental samples compared to the high diversity of the clinical samples. Some clinical strains were genetically more similar to environmental strains than to other clinical strains, including those from the same patient. CONCLUSION These results provide new information on the ecology and epidemiology of the C. neoformans/C. gattii species complex in Ivory Coast.
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Affiliation(s)
- Fulgence K Kassi
- Laboratoire de Parasitologie et de Mycologie - CeDReS (Centre de Diagnostic et de Recherche sur le SIDA et les Autres Maladies Infectieuses), UFR Pharmacie, CHU de Treichville, Université Félix Houphouët Boigny, Abidjan, Ivory Coast
| | - Virginie Bellet
- UMI 233 IRD-UM INSERM U1175 TransVIHMI, Groupe Infections Fongique et Parasitaire Laboratoire de Parasitologie et de Mycologie Médicale, UFR Pharmacie, Montpellier Cedex 5, France
| | - Pascal Drakulovski
- UMI 233 IRD-UM INSERM U1175 TransVIHMI, Groupe Infections Fongique et Parasitaire Laboratoire de Parasitologie et de Mycologie Médicale, UFR Pharmacie, Montpellier Cedex 5, France
| | - Donika Krasteva
- UMI 233 IRD-UM INSERM U1175 TransVIHMI, Groupe Infections Fongique et Parasitaire Laboratoire de Parasitologie et de Mycologie Médicale, UFR Pharmacie, Montpellier Cedex 5, France
| | - Frédéric Roger
- UMI 233 IRD-UM INSERM U1175 TransVIHMI, Groupe Infections Fongique et Parasitaire Laboratoire de Parasitologie et de Mycologie Médicale, UFR Pharmacie, Montpellier Cedex 5, France
| | - Bedia-Tanoh A Valérie
- Laboratoire de Parasitologie et de Mycologie - CeDReS (Centre de Diagnostic et de Recherche sur le SIDA et les Autres Maladies Infectieuses), UFR Pharmacie, CHU de Treichville, Université Félix Houphouët Boigny, Abidjan, Ivory Coast
| | - Touré Aboubakar
- Laboratoire de Parasitologie et de Mycologie - CeDReS (Centre de Diagnostic et de Recherche sur le SIDA et les Autres Maladies Infectieuses), UFR Pharmacie, CHU de Treichville, Université Félix Houphouët Boigny, Abidjan, Ivory Coast
| | - Adama Doumbia
- Service des Maladies Infectieuses et Tropicales, CHU de Treichville, Abidjan, Ivory Coast
| | - Gisèle A Kouakou
- Service des Maladies Infectieuses et Tropicales, CHU de Treichville, Abidjan, Ivory Coast
| | - Eric Delaporte
- UMI 233 Service des Maladies Infectieuses et Tropicales, CHU Gui de Chauliac, Montpellier, France
| | - Jacques Reynes
- UMI 233 Service des Maladies Infectieuses et Tropicales, CHU Gui de Chauliac, Montpellier, France
| | - William Yavo
- Laboratoire de Parasitologie et de Mycologie - CeDReS (Centre de Diagnostic et de Recherche sur le SIDA et les Autres Maladies Infectieuses), UFR Pharmacie, CHU de Treichville, Université Félix Houphouët Boigny, Abidjan, Ivory Coast
| | - Hervé I E Menan
- Laboratoire de Parasitologie et de Mycologie - CeDReS (Centre de Diagnostic et de Recherche sur le SIDA et les Autres Maladies Infectieuses), UFR Pharmacie, CHU de Treichville, Université Félix Houphouët Boigny, Abidjan, Ivory Coast
| | - Sebastien Bertout
- UMI 233 IRD-UM INSERM U1175 TransVIHMI, Groupe Infections Fongique et Parasitaire Laboratoire de Parasitologie et de Mycologie Médicale, UFR Pharmacie, Montpellier Cedex 5, France
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Feliciano LM, Ramos SDP, Szeszs MW, Martins MA, Bonfietti LX, Oliveira RA, Santos DCS, Fadul LH, Silva DF, Paula CR, Trilles L, Silva LEA, Ferreira-Paim K, Mora DJ, Andrade AA, Silva PR, Silva-Vergara ML, Roberto TN, Melhem MSC. Heteroresistance to Fluconazol in Clinical and Environmental Brazilian Strains of Cryptococcus neoformans/C. gattii Species Complex. CURRENT FUNGAL INFECTION REPORTS 2017. [DOI: 10.1007/s12281-017-0298-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Yamaguchi H. Potential of Ravuconazole and its Prodrugs as the New OralTherapeutics for Onychomycosis. Med Mycol J 2017; 57:E93-E110. [PMID: 27904057 DOI: 10.3314/mmj.16-00006] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Onychomycosis is a fungal infection of the nail apparatus caused by dermatophytes, Candida and non-dermatophytic molds. It is highly prevalent in the general population worldwide and also responsible for significant morbidity and complications and does not usually cure itself. Thus, the condition needs to be treated in view of physical and psychological problems produced. Currently, oral medications using terbinafine are the most effective therapy, but it has relatively limited therapeutic success, particularly for long-term management. Such existing oral therapies are associated with high recurrence rates and treatment failure, as well as with potential adverse events and drug-drug interactions. In the light of these issues, development of more efficacious and safer alternatives for the treatment of onychomycosis is warranted.Ravuconazole and its prodrugs are promising new drug candidates for oral therapy of onychomycosis, among which a water-soluble prodrug, mono-lysine phosphoester derivative (E1224 or BFE1224) is in the most advanced stage of clinical development; a Phase II dose-finding study has been successfully completed and Phase III comparative studies are in progress in Japan.This review aims to summarize our current status of knowledge and information on ravuconazole and its prodrugs, particularly BFE1224, as the potential oral treatment option for onychomycosis. It also summarize the clinical features of onychomycosis with particular stress on its etiology, epidemiology, and current therapeutic options and their limitations. Given its clinical usefulness, BFE1224 may become a valuable addition to the current armamentarium for the treatment of onychomycosis.
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Lahiri Mukhopadhyay S, Bahubali VH, Manjunath N, Swaminathan A, Maji S, Palaniappan M, Parthasarathy S, Chandrashekar N. Central nervous system infection due to Cryptococcus gattii sensu lato
in India: Analysis of clinical features, molecular profile and antifungal susceptibility. Mycoses 2017; 60:749-757. [DOI: 10.1111/myc.12656] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Revised: 06/21/2017] [Accepted: 06/22/2017] [Indexed: 12/16/2022]
Affiliation(s)
| | - Veenakumari H. Bahubali
- Department of Neuromicrobiology; National Institute of Mental Health and Neuro Sciences; Bangalore India
| | - Netravathi Manjunath
- Department of Neurology; National Institute of Mental Health and Neuro Sciences; Bangalore India
| | - Aarthi Swaminathan
- Department of Neuroimaging and Interventional Radiology; National Institute of Mental Health and Neuro Sciences; Bangalore India
| | - Sayani Maji
- Department of Neuromicrobiology; National Institute of Mental Health and Neuro Sciences; Bangalore India
| | - Marimuthu Palaniappan
- Department of Biostatistics; National Institute of Mental Health and Neuro Sciences; Bangalore India
| | | | - Nagarathna Chandrashekar
- Department of Neuromicrobiology; National Institute of Mental Health and Neuro Sciences; Bangalore India
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Aminnejad M, Cogliati M, Duan S, Arabatzis M, Tintelnot K, Castañeda E, Lazéra M, Velegraki A, Ellis D, Sorrell TC, Meyer W. Identification and Characterization of VNI/VNII and Novel VNII/VNIV Hybrids and Impact of Hybridization on Virulence and Antifungal Susceptibility Within the C. neoformans/C. gattii Species Complex. PLoS One 2016; 11:e0163955. [PMID: 27764108 PMCID: PMC5072701 DOI: 10.1371/journal.pone.0163955] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 09/16/2016] [Indexed: 12/14/2022] Open
Abstract
Cryptococcus neoformans and C. gattii are pathogenic basidiomycetous yeasts and the commonest cause of fungal infection of the central nervous system. Cryptococci are typically haploid but several inter-species, inter-varietal and intra-varietal hybrids have been reported. It has a bipolar mating system with sexual reproduction occurring normally between two individuals with opposite mating types, α and a. This study set out to characterize hybrid isolates within the C. neoformans/C. gattii species complex: seven unisexual mating intra-varietal VNI/VNII (αAAα) and six novel inter-varietal VNII/VNIV (aADα). The URA5-RFLP pattern for VNII/VNIV (aADα) differs from the VNIII (αADa) hybrids. Analysis of the allelic patterns of selected genes for AD hybrids showed 79% or more heterozygosis for the studied loci except for CBS132 (VNIII), which showed 50% of heterozygosity. MALDI-TOF MS was applied to hybrids belonging to different sero/mating type allelic patterns. All hybrid isolates were identified as belonging to the same hybrid group with identification scores ranging between 2.101 to 2.634. All hybrids were virulent when tested in the Galleria mellonella (wax moth) model, except for VNII/VNIV (aADα) hybrids. VNI/VGII hybrids were the most virulent hybrids. Hybrids recovered from larvae manifested a significant increase in capsule and total cell size and produced a low proportion (5-10%) of giant cells compared with the haploid control strains. All strains expressed the major virulence factors-capsule, melanin and phospholipase B-and grew well at 37°C. The minimal inhibitory concentration of nine drugs was measured by micro-broth dilution and compared with published data on haploid strains. MICs were similar amongst hybrids and haploid parental strains. This is the first study reporting natural same sex αAAα intra-varietal VNI/VNII hybrids and aADα inter-varietal VNII/VNIV hybrids.
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Affiliation(s)
- Mojgan Aminnejad
- Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Sydney Medical School – Westmead Hospital, Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, Westmead Institute for Medical Research, Sydney, Australia
| | - Massimo Cogliati
- Laboratory Micologia Medica, Dip. Scienze Biomediche per la Salute, Università degli Studi di Milano, Milano, Italy
| | - Shuyao Duan
- Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Sydney Medical School – Westmead Hospital, Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, Westmead Institute for Medical Research, Sydney, Australia
| | - Michael Arabatzis
- Mycology Research Laboratory, Department of Microbiology, Medical School, National Kapodistrian University of Athens, Athens, Greece
| | | | | | - Marcia Lazéra
- Mycology Laboratory, National Institute of Infectious Diseases, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Aristea Velegraki
- Mycology Research Laboratory, Department of Microbiology, Medical School, National Kapodistrian University of Athens, Athens, Greece
| | - David Ellis
- School of Molecular & Biomedical Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - Tania C. Sorrell
- Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Sydney Medical School – Westmead Hospital, Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, Westmead Institute for Medical Research, Sydney, Australia
| | - Wieland Meyer
- Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Sydney Medical School – Westmead Hospital, Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, Westmead Institute for Medical Research, Sydney, Australia
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The Investigational Fungal Cyp51 Inhibitor VT-1129 Demonstrates Potent In Vitro Activity against Cryptococcus neoformans and Cryptococcus gattii. Antimicrob Agents Chemother 2016; 60:2528-31. [PMID: 26787697 DOI: 10.1128/aac.02770-15] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 01/12/2016] [Indexed: 12/28/2022] Open
Abstract
Thein vitroactivities of the novel fungal Cyp51 inhibitor VT-1129 were evaluated against a large panel ofCryptococcus neoformansandCryptococcus gattiiisolates. VT-1129 demonstrated potent activities against bothCryptococcusspecies as demonstrated by low MIC50and MIC90values. ForC. gattii, thein vitropotency was maintained against all genotypes. In addition, significantly lower geometric mean MICs were observed for VT-1129 than for fluconazole againstC. neoformans, including isolates with reduced fluconazole susceptibility.
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Gutch RS, Nawange SR, Singh SM, Yadu R, Tiwari A, Gumasta R, Kavishwar A. Antifungal susceptibility of clinical and environmental Cryptococcus neoformans and Cryptococcus gattii isolates in Jabalpur, a city of Madhya Pradesh in Central India. Braz J Microbiol 2015; 46:1125-33. [PMID: 26691471 PMCID: PMC4704646 DOI: 10.1590/s1517-838246420140564] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 12/28/2014] [Indexed: 11/22/2022] Open
Abstract
In this study, we present antifungal susceptibility data of clinical and
environmental isolates of Central Indian Cryptococcus neoformans
(Serotype A, n = 8 and n = 50 respectively) and Cryptococcus gattii
(Serotype B, n = 01 and n = 04 respectively). Susceptibilities to fluconazole,
itraconazole and ketoconazole were determined by using NCCLS broth micro-dilution
methodology. The total number of resistant strains for fluconazole in case of
C. neoformans and C. gattii showed a significant
difference by using chi-square test (p < 0.05*), while considering fisher's exact
p value was nonsignificant (p > 0.05). However, the total number of resistant
strains for itraconazole and ketoconazole was not found statistically significant. A
comparison of geometric means of clinical and environmental strains of C.
gattii and C. neoformans was not found statistically
significant using student ‘t’ test (p value > 0.05 NS). Though less, the
antifungal data obtained in this study suggests that primary resistance among
environmental and clinical isolates of C. neoformans and C.
gattii against tested antifungal was present and C.
gattii comparatively was less susceptible than C.
neoformans var. grubii isolates to fluconazole than to
itraconazole and ketoconazole. A continuous surveillance of antifungal susceptibility
of clinical and environmental isolates of C. neoformans and
C. gattii is desirable to monitor the emergence of any resistant
strains for better management of cryptococcosis patients.
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Affiliation(s)
- Ruchi Sethi Gutch
- Department of Biological Sciences, Rani Durgavati University, Madhya Pradesh, India
| | - Shesh Rao Nawange
- Department of Biological Sciences, Rani Durgavati University, Madhya Pradesh, India
| | - Shankar Mohan Singh
- Department of Biological Sciences, Rani Durgavati University, Madhya Pradesh, India
| | - Ruchika Yadu
- Department of Biological Sciences, Rani Durgavati University, Madhya Pradesh, India
| | - Aditi Tiwari
- Department of Biological Sciences, Rani Durgavati University, Madhya Pradesh, India
| | - Richa Gumasta
- Department of Biological Sciences, Rani Durgavati University, Madhya Pradesh, India
| | - Arvind Kavishwar
- National Institute For Research In Tribal Health, Madhya Pradesh, India
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Abstract
Understanding of the taxonomy and phylogeny of Cryptococcus gattii has been advanced by modern molecular techniques. C. gattii probably diverged from Cryptococcus neoformans between 16 million and 160 million years ago, depending on the dating methods applied, and maintains diversity by recombining in nature. South America is the likely source of the virulent C. gattii VGII molecular types that have emerged in North America. C. gattii shares major virulence determinants with C. neoformans, although genomic and transcriptomic studies revealed that despite similar genomes, the VGIIa and VGIIb subtypes employ very different transcriptional circuits and manifest differences in virulence phenotypes. Preliminary evidence suggests that C. gattii VGII causes severe lung disease and death without dissemination, whereas C. neoformans disseminates readily to the central nervous system (CNS) and causes death from meningoencephalitis. Overall, currently available data indicate that the C. gattii VGI, VGII, and VGIII molecular types more commonly affect nonimmunocompromised hosts, in contrast to VGIV. New, rapid, cheap diagnostic tests and imaging modalities are assisting early diagnosis and enabling better outcomes of cerebral cryptococcosis. Complications of CNS infection include increased intracranial pressure, severe neurological sequelae, and development of immune reconstitution syndrome, although the mortality rate is low. C. gattii VGII isolates may exhibit higher fluconazole MICs than other genotypes. Optimal therapeutic regimens are yet to be determined; in most cases, initial therapy with amphotericin B and 5-flucytosine is recommended.
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Mukhopadhyay SL, Kumar M, Chickabasaviah YT, Bahubali VKH, Raj PA, Bharath RD, Siddaiah N. Cerebellar cryptococcoma due to Cryptococcus gattii VGI; a rare and first report from India. JMM Case Rep 2015. [DOI: 10.1099/jmmcr.0.000052] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
| | - Mukesh Kumar
- National institute of Mental Health and Neuro Sciences, Hosur Road, Bangalore 560029, Karnataka, India
| | - Yasha T. Chickabasaviah
- National institute of Mental Health and Neuro Sciences, Hosur Road, Bangalore 560029, Karnataka, India
| | - Veena Kumari H. Bahubali
- National institute of Mental Health and Neuro Sciences, Hosur Road, Bangalore 560029, Karnataka, India
| | - Prabhu A.R. Raj
- National institute of Mental Health and Neuro Sciences, Hosur Road, Bangalore 560029, Karnataka, India
| | - Rose Dawn Bharath
- National institute of Mental Health and Neuro Sciences, Hosur Road, Bangalore 560029, Karnataka, India
| | - Nagarathna Siddaiah
- National institute of Mental Health and Neuro Sciences, Hosur Road, Bangalore 560029, Karnataka, India
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Harris JR, Galanis E, Lockhart SR. Cryptococcus gattii Infections and Virulence. CURRENT FUNGAL INFECTION REPORTS 2014. [DOI: 10.1007/s12281-013-0170-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Pharmacokinetics of fluconazole following intravenous and oral administration to koalas (Phascolarctos cinereus
). J Vet Pharmacol Ther 2013; 37:90-8. [DOI: 10.1111/jvp.12072] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 07/05/2013] [Indexed: 11/26/2022]
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Chen SCA, Korman TM, Slavin MA, Marriott D, Byth K, Bak N, Currie BJ, Hajkowicz K, Heath CH, Kidd S, McBride WJH, Meyer W, Murray R, Playford EG, Sorrell TC. Antifungal therapy and management of complications of cryptococcosis due to Cryptococcus gattii. Clin Infect Dis 2013; 57:543-51. [PMID: 23697747 DOI: 10.1093/cid/cit341] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND We describe antifungal therapy and management of complications due to Cryptococcus gattii infection in 86 Australian patients followed for at least 12 months. METHODS Patient data from culture-confirmed cases (2000-2007) were recorded at diagnosis, 6 weeks, 6 months, and 12 months. Clinical, laboratory, and treatment variables associated with raised intracranial pressure (ICP) and immune reconstitution inflammatory syndrome (IRIS) were determined. RESULTS Seven of 10 patients with lung infection received amphotericin B (AMB) induction therapy (6 with 5-flucytosine [5-FC] for a median of 2 weeks); median duration of therapy including azole eradication therapy was 41 weeks, with a complete/partial clinical response in 78%. For neurologic disease, 88% of patients received AMB, 78% with 5-FC, for a median of 6 weeks. The median total course was 18 months. Nine patients receiving fluconazole induction therapy were reinduced with AMB plus 5-FC for clinical failure. Raised ICP (31 patients) was associated with initial abnormal neurology, and neurologic sequelae and/or death at 12 months (both P = .02); cerebrospinal fluid drains/shunts were placed in 58% of patients and in 64% of 22 patients with hydrocephalus. IRIS developed 2-12 months after starting antifungals in 8 patients, who presented with new/enlarging brain lesions. Risk factors included female sex, brain involvement at presentation, and higher median CD4 counts (all P < .05); corticosteroids reduced cryptococcoma-associated edema. CONCLUSIONS Induction AMB plus 5-FC is indicated for C. gattii neurologic cryptococcosis (6 weeks) and when localized to lung (2 weeks). Shunting was often required to control raised ICP. IRIS presents with cerebral manifestations.
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Affiliation(s)
- Sharon C-A Chen
- Centre for Infectious Diseases and Microbiology and The Sydney Institute for Emerging Infections and Biosecurity, Sydney Medical School, University of Sydney, Australia.
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Ferreira GF, Baltazar LDM, Santos JRA, Monteiro AS, Fraga LADO, Resende-Stoianoff MA, Santos DA. The role of oxidative and nitrosative bursts caused by azoles and amphotericin B against the fungal pathogen Cryptococcus gattii. J Antimicrob Chemother 2013; 68:1801-11. [PMID: 23612570 DOI: 10.1093/jac/dkt114] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
OBJECTIVES Although the most accepted mechanisms of action of amphotericin B and azoles are related to ergosterol, it is possible that these drugs have other effects on the fungal cell. In the present study, the role of endogenous reactive oxygen species (ROS) and peroxynitrite produced by azoles and amphotericin B in the fungus Cryptococcus gattii were examined. METHODS We studied distinct parameters to evaluate the effect of oxidative and nitrosative stresses induced by these drugs in C. gattii cells: lipid peroxidation, ergosterol content, ROS and peroxynitrite production, enzymatic activity of the antioxidant system and the in vitro interaction of antifungal drugs with a peroxidase inhibitor, a superoxide dismutase inhibitor and a peroxynitrite scavenger. RESULTS The data demonstrated that itraconazole led to ROS formation and lipid peroxidation in C. gattii cells in the early stages of the treatment; this did not occur with fluconazole. This phenomenon strongly increased the activities of enzymes of the antioxidant system. These results were confirmed by synergism observed between the catalase inhibitor and itraconazole. Amphotericin B caused lipid peroxidation in C. gattii cells through a greatly enhanced production of oxidative and nitrosative radicals with increased peroxidase activity. These data were confirmed by the synergism between the catalase/superoxide dismutase inhibitors and amphotericin B. In addition, the effect of this antifungal was antagonized by the peroxynitrite scavenger. CONCLUSIONS Oxidative and nitrosative bursts play an important role in the antifungal activity of itraconazole and amphotericin B against C. gattii.
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Affiliation(s)
- Gabriella Freitas Ferreira
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, MG, Brazil
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Development of a singleplex PCR assay for rapid identification and differentiation of Cryptococcus neoformans var. grubii, Cryptococcus neoformans var. neoformans, Cryptococcus gattii, and hybrids. J Clin Microbiol 2013; 51:1920-3. [PMID: 23536400 DOI: 10.1128/jcm.00064-13] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A singleplex PCR assay using a single primer pair targeting the putative sugar transporter gene was developed here to distinguish Cryptococcus neoformans var. grubii, Cryptococcus neoformans var. neoformans, and Cryptococcus gattii according to the distinct size of the amplicon. The interspecies and intravarietal hybrids were also characterized on the basis of distinct combined profiles of amplicons. This PCR assay is a rapid, simple, and reliable approach suitable for laboratory diagnoses and large-scale epidemiologic studies.
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Cordeiro RDA, Nogueira GC, Brilhante RSN, Teixeira CEC, Mourão CI, Castelo-Branco DDSCM, Paiva MDAN, Ribeiro JF, Monteiro AJ, Sidrim JJC, Rocha MFG. Farnesol inhibits in vitro growth of the Cryptococcus neoformans species complex with no significant changes in virulence-related exoenzymes. Vet Microbiol 2012; 159:375-80. [DOI: 10.1016/j.vetmic.2012.04.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2011] [Revised: 04/04/2012] [Accepted: 04/05/2012] [Indexed: 10/28/2022]
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Firacative C, Trilles L, Meyer W. MALDI-TOF MS enables the rapid identification of the major molecular types within the Cryptococcus neoformans/C. gattii species complex. PLoS One 2012; 7:e37566. [PMID: 22666368 PMCID: PMC3362595 DOI: 10.1371/journal.pone.0037566] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Accepted: 04/20/2012] [Indexed: 12/14/2022] Open
Abstract
Background The Cryptococcus neoformans/C. gattii species complex comprises two sibling species that are divided into eight major molecular types, C. neoformans VNI to VNIV and C. gattii VGI to VGIV. These genotypes differ in host range, epidemiology, virulence, antifungal susceptibility and geographic distribution. The currently used phenotypic and molecular identification methods for the species/molecular types are time consuming and expensive. As Matrix-Assisted Laser Desorption Ionization-Time-of-Flight Mass Spectrometry (MALDI-TOF MS) offers an effective alternative for the rapid identification of microorganisms, the objective of this study was to examine its potential for the identification of C. neoformans and C. gattii strains at the intra- and inter-species level. Methodology Protein extracts obtained via the formic acid extraction method of 164 C. neoformans/C. gattii isolates, including four inter-species hybrids, were studied. Results The obtained mass spectra correctly identified 100% of all studied isolates, grouped each isolate according to the currently recognized species, C. neoformans and C. gattii, and detected potential hybrids. In addition, all isolates were clearly separated according to their major molecular type, generating greater spectral differences among the C. neoformans molecular types than the C. gattii molecular types, most likely reflecting a closer phylogenetic relationship between the latter. The number of colonies used and the incubation length did not affect the results. No spectra were obtained from intact yeast cells. An extended validated spectral library containing spectra of all eight major molecular types was established. Conclusions MALDI-TOF MS is a rapid identification tool for the correct recognition of the two currently recognized human pathogenic Cryptococcus species and offers a simple method for the separation of the eight major molecular types and the detection of hybrid strains within this species complex in the clinical laboratory. The obtained mass spectra provide further evidence that the major molecular types warrant variety or even species status.
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Affiliation(s)
- Carolina Firacative
- Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Westmead Millennium Institute, Sydney Medical School–Westmead, The University of Sydney, Westmead Hospital, Sydney, Australia
- Grupo de Microbiología, Instituto Nacional de Salud, Bogotá, Colombia
| | - Luciana Trilles
- Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Westmead Millennium Institute, Sydney Medical School–Westmead, The University of Sydney, Westmead Hospital, Sydney, Australia
- Laboratório de Micologia, Instituto de Pesquisa Clínica Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Wieland Meyer
- Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Westmead Millennium Institute, Sydney Medical School–Westmead, The University of Sydney, Westmead Hospital, Sydney, Australia
- * E-mail:
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Lockhart SR, Iqbal N, Bolden CB, DeBess EE, Marsden-Haug N, Worhle R, Thakur R, Harris JR. Epidemiologic cutoff values for triazole drugs in Cryptococcus gattii: correlation of molecular type and in vitro susceptibility. Diagn Microbiol Infect Dis 2012; 73:144-8. [PMID: 22494557 DOI: 10.1016/j.diagmicrobio.2012.02.018] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 02/21/2012] [Accepted: 02/21/2012] [Indexed: 01/12/2023]
Abstract
Cryptococcus gattii causes infection in tropical and subtropical regions worldwide but has garnered increased attention since its 1999 emergence in North America. C. gattii can be divided into 4 molecular types that may represent cryptic species. Recent evidence has shown that azole antifungal MIC values differ among these molecular types. We tested a large collection of C. gattii isolates for susceptibility to 4 azole drugs. We found that isolates of molecular type VGII have the highest geometric mean (GM) fluconazole MIC values (8.6 μg/mL), while isolates of molecular type VGI have the lowest (1.7 μg/mL). For fluconazole, itraconazole, and voriconazole GM MIC values, VGI < VGIII < VGIV < VGII. The GM MIC values for posaconazole were similarly represented across molecular types, with the exception that VGII < VGIII and VGIV. We used the MIC values to establish preliminary epidemiologic cutoff values for each azole and molecular type of C. gattii.
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Affiliation(s)
- Shawn R Lockhart
- Mycotic Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
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Silva DC, Martins MA, Szeszs MW, Bonfietti LX, Matos D, Melhem MSC. Susceptibility to antifungal agents and genotypes of Brazilian clinical and environmental Cryptococcus gattii strains. Diagn Microbiol Infect Dis 2012; 72:332-9. [PMID: 22341512 DOI: 10.1016/j.diagmicrobio.2011.11.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Revised: 11/21/2011] [Accepted: 11/23/2011] [Indexed: 11/26/2022]
Abstract
There are few reports concerning the in vitro antifungal susceptibility of clinical and environmental Cryptococcus gattii isolates. In this study, we performed polymerase chain reaction-restriction fragment length polymorphism to investigate the molecular subtypes of 50 clinical and 4 environmental Brazilian isolates of C. gattii and assessed their antifungal susceptibility for fluconazole (FLU) and amphotericin B (Amb) according to recent recommendations proposed for antifungal susceptibility testing of nonfermentative yeasts. Time-kill curve studies were performed using RPMI 1640 medium to analyze the fungicidal effect of AmB. We found 47 VGII (94%) molecular types and 3 VGI (6%) types among the clinical isolates. The environmental isolates were VGII (75%) subtype and VGI (25%) subtype. The FLU-MIC ranged from 1 to 64 mg L(-1), and MIC(50)/MIC(90) values were, respectively, 8/16 mg L(-1). For AmB, the MICs were low and homogeneous, ranging from 0.12 to 0.5 mg L(-1), for VGI or VGII. The time required to reach the fungicidal end point (99.9% killing) was 6 h for the majority of strains (64%), but viable cells of VGII were still present after 48 h of exposition. We pointed out the occurrence of high FLU-MICs for C. gattii isolates with highest values for VGII. Our data also suggest that the rate of killing of C. gattii by AmB is strain dependent, and viable cells of VGII genotype strains were still observed after an extended incubation time, addressing future studies to determine whether the in vitro fungicidal activity could be clinically relevant.
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Affiliation(s)
- Dayane C Silva
- Mycology Unit of Adolfo Lutz Institute, Public Health Reference Laboratory, Secretary of Health, São Paulo-SP, 01246-902, Brazil
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Trilles L, Meyer W, Wanke B, Guarro J, Lazéra M. Correlation of antifungal susceptibility and molecular type within the Cryptococcus neoformans/C. gattii species complex. Med Mycol 2011; 50:328-32. [PMID: 21859388 DOI: 10.3109/13693786.2011.602126] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Members of the Cryptococcus neoformans/C. gattii species complex are grouped into eight molecular types, differing in their epidemiology, disease severity and geographic range. Recent in vitro antifungal susceptibility studies of isolates of the complex revealed contradictory results. The objective of the present study was to assess if this variation is random or correlates with different molecular types by testing the in vitro antifungal susceptibility of 18 C. neoformans (VNI), 11 C. gattii (VGI) and 38 C. gattii (VGII) strains from Brazil to eight antifungal drugs using the CLSI microdilution method. We herein report that the molecular type VGII is the least susceptible genotype, followed by VGI and VNI. This indicates a clear correlation between antifungal susceptibilities and genotypes of the causative cryptococcosis agents, emphasizing the importance of determining the molecular type as part of the clinical diagnostic process to enable an informed decision as to the most appropriate antifungal treatment.
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Affiliation(s)
- Luciana Trilles
- Evandro Chagas Clinical Research Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil. ocruz.br
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Pitman SK, Drew RH, Perfect JR. Addressing current medical needs in invasive fungal infection prevention and treatment with new antifungal agents, strategies and formulations. Expert Opin Emerg Drugs 2011; 16:559-586. [DOI: 10.1517/14728214.2011.607811] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Chowdhary A, Randhawa HS, Sundar G, Kathuria S, Prakash A, Khan Z, Sun S, Xu J. In vitro antifungal susceptibility profiles and genotypes of 308 clinical and environmental isolates of Cryptococcus neoformans var. grubii and Cryptococcus gattii serotype B from north-western India. J Med Microbiol 2011; 60:961-967. [DOI: 10.1099/jmm.0.029025-0] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Anuradha Chowdhary
- Department of Medical Mycology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi 11007, India
| | - Harbans Singh Randhawa
- Department of Medical Mycology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi 11007, India
| | - Gandhi Sundar
- Department of Medical Mycology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi 11007, India
| | - Shallu Kathuria
- Department of Medical Mycology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi 11007, India
| | - Anupam Prakash
- Department of Medical Mycology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi 11007, India
| | - Ziauddin Khan
- Mycology Reference Laboratory, Department of Microbiology, Faculty of Medicine, Kuwait University, Safat, Kuwait
| | - Sheng Sun
- Institute of Infectious Disease Research, Michael G. DeGroote School of Medicine, and Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Jianping Xu
- Institute of Infectious Disease Research, Michael G. DeGroote School of Medicine, and Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
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Rapid identification of Cryptococcus neoformans and Cryptococcus gattii by matrix-assisted laser desorption ionization-time of flight mass spectrometry. J Clin Microbiol 2011; 49:3050-3. [PMID: 21653762 DOI: 10.1128/jcm.00651-11] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Compared to DNA sequence analysis, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) correctly identified 100% of Cryptococcus species, distinguishing the notable pathogens Cryptococcus neoformans and C. gattii. Identification was greatly enhanced by supplementing a commercial spectral library with additional entries to account for subspecies variability.
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Rapid identification of Cryptococcus neoformans var. grubii, C. neoformans var. neoformans, and C. gattii by use of rapid biochemical tests, differential media, and DNA sequencing. J Clin Microbiol 2011; 49:2522-7. [PMID: 21593254 DOI: 10.1128/jcm.00502-11] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rapid identification of Cryptococcus neoformans var. grubii, Cryptococcus neoformans var. neoformans, and Cryptococcus gattii is imperative for facilitation of prompt treatment of cryptococcosis and for understanding the epidemiology of the disease. Our purpose was to evaluate a test algorithm incorporating commercial rapid biochemical tests, differential media, and DNA sequence analysis that will allow us to differentiate these taxa rapidly and accurately. We assessed 147 type, reference, and clinical isolates, including 6 other Cryptococcus spp. (10 isolates) and 14 other yeast species (24 isolates), using a 4-hour urea broth test (Remel), a 24-hour urea broth test (Becton Dickinson), a 4-hour caffeic acid disk test (Hardy Diagnostics and Remel), 40- to 44-hour growth assessment on l-canavanine glycine bromothymol blue (CGB) agar, and intergenic spacer (IGS) sequence analysis. All 123 Cryptococcus isolates hydrolyzed urea, along with 7 isolates of Rhodotorula and Trichosporon. Eighty-five of 86 C. neoformans (99%) and 26 of 27 C. gattii (96%) isolates had positive caffeic acid results, unlike the other cryptococci (0/10) and yeast species (0/24). Together, these two tests positively identified virtually all C. neoformans/C. gattii isolates (98%) within 4 h. CGB agar or IGS sequencing further differentiated these isolates within 48 h. On CGB, 25 of 27 (93%) C. gattii strains induced a blue color change, in contrast to 0 of 86 C. neoformans isolates. Neighbor-joining cluster analysis of IGS sequences differentiated C. neoformans var. grubii, C. neoformans var. neoformans, and C. gattii. Based on these results, we describe a rapid identification algorithm for use in a microbiology laboratory to distinguish clinically relevant Cryptococcus spp.
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Soares BM, Alves OA, Ferreira MVL, Amorim JCF, Sousa GR, Silveira LDB, Prates RA, Avila TV, Baltazar LDM, de Souza DDG, Santos DA, Modolo LV, Cisalpino PS, Pinotti M. Cryptococcus gattii: in vitro susceptibility to photodynamic inactivation. Photochem Photobiol 2010; 87:357-64. [PMID: 21114500 DOI: 10.1111/j.1751-1097.2010.00868.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cryptococus gattii is an emergent primary human pathogen that causes meningismus, papilledema, high intracranial pressure and focal involvement of the central nervous system in immunocompetent hosts. Prolonged antifungal therapy is the conventional treatment, but it is highly toxic, selects for resistant strains, contributes to therapy failure and has a poor prognosis. Photodynamic inactivation (PDI) offers a promising possibility for the alternative treatment of cryptococcosis. The aim of this study was to test the effectiveness of toluidine blue O (TBO) and light-emitting diode (LED) against C. gattii strains with distinct susceptibility profile to antifungal drugs (amphotericin B: 0.015-1.0 μg mL(-1); itraconazole: 0.015-2 μg mL(-1); fluconazole: 4-64 μg mL(-1)). Using 25 μM (6.76 μg mL(-1)) TBO and LED energy density of 54 J cm(-2) these fungal isolates presented variable susceptibility to PDI. The production of reactive oxygen species (ROS)/peroxynitrite was determined, and the catalase and peroxidase activities were measured. After PDI, high amounts of ROS/peroxynitrite are produced and higher catalase and peroxidase activities could be correlated with a lower susceptibility of C. gattii isolates to PDI. These results indicate that PDI could be an alternative to C. gattii growth inhibition, even of isolates less susceptible to classical antifungal drugs, also pointing to mechanisms related to their variable susceptibility behavior.
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Affiliation(s)
- Betânia Maria Soares
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
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In vitro antifungal susceptibilities and amplified fragment length polymorphism genotyping of a worldwide collection of 350 clinical, veterinary, and environmental Cryptococcus gattii isolates. Antimicrob Agents Chemother 2010; 54:5139-45. [PMID: 20855729 DOI: 10.1128/aac.00746-10] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The in vitro susceptibilities of a worldwide collection of 350 Cryptococcus gattii isolates to seven antifungal drugs, including the new triazole isavuconazole, were tested. With amplified fragment length polymorphism (AFLP) fingerprinting, human, veterinary, and environmental C. gattii isolates were subdivided into seven AFLP genotypes, including the interspecies hybrids AFLP8 and AFLP9. The majority of clinical isolates (n = 215) comprised genotypes AFLP4 (n = 76) and AFLP6 (n = 103). The clinical AFLP6 isolates had significantly higher geometric mean MICs for flucytosine and fluconazole than the clinical AFLP4 isolates. Of the seven antifungal compounds examined in this study, isavuconazole had the lowest MIC(90) (0.125 μg/ml) for all C. gattii isolates, followed by a 1 log(2) dilution step increase (MIC(90), 0.25 μg/ml) for itraconazole, voriconazole, and posaconazole. Amphotericin B had an acceptable MIC(90) of 0.5 μg/ml, but fluconazole and flucytosine had relatively high MIC(90)s of 8 μg/ml.
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In vitro susceptibility of the yeast pathogen cryptococcus to fluconazole and other azoles varies with molecular genotype. J Clin Microbiol 2010; 48:4115-20. [PMID: 20844209 DOI: 10.1128/jcm.01271-10] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Cryptococcosis is primarily caused by Cryptococcus neoformans and Cryptococcus gattii. These two pathogenic species each divide into four distinct molecular genotypes. In this study, we examined whether genotype influenced susceptibility to antifungal drugs used to treat cryptococcosis using the broth microdilution method described by the Clinical and Laboratory Standards Institute. C. gattii isolates belonging to molecular genotype VGII had significantly higher MIC values for flucytosine and all azole antifungal agents tested, particularly fluconazole, than isolates of other C. gattii genotypes. In an extended analysis of fluconazole susceptibility, VGII isolates from the north and west of Australia required higher drug levels for inhibition than those from Vancouver Island, Canada. Within C. neoformans, genotype VNII had significantly lower geometric mean MICs for fluconazole than genotype VNI. These results indicate that cryptococcal species, molecular genotype, and region of origin may be important when deciding treatment options for cryptococcosis.
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Chau TT, Mai NH, Phu NH, Nghia HD, Chuong LV, Sinh DX, Duong VA, Diep PT, Campbell JI, Baker S, Hien TT, Lalloo DG, Farrar JJ, Day JN. A prospective descriptive study of cryptococcal meningitis in HIV uninfected patients in Vietnam - high prevalence of Cryptococcus neoformans var grubii in the absence of underlying disease. BMC Infect Dis 2010; 10:199. [PMID: 20618932 PMCID: PMC2910700 DOI: 10.1186/1471-2334-10-199] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Accepted: 07/09/2010] [Indexed: 11/14/2022] Open
Abstract
Background Most cases of cryptococcal meningitis occur in patients with HIV infection: the course and outcome of disease in the apparently immunocompetent is much more poorly understood. We describe a cohort of HIV uninfected Vietnamese patients with cryptococcal meningitis in whom underlying disease is uncommon, and relate presenting features of patients and the characteristics of the infecting species to outcome. Methods A prospective descriptive study of HIV negative patients with cryptococcal meningitis based at the Hospital for Tropical Diseases, Ho Chi Minh City. All patients had comprehensive clinical assessment at baseline, were cared for by a dedicated study team, and were followed up for 2 years. Clinical presentation was compared by infecting isolate and outcome. Results 57 patients were studied. Cryptococcus neoformans var grubii molecular type VN1 caused 70% of infections; C. gattii accounted for the rest. Most patients did not have underlying disease (81%), and the rate of underlying disease did not differ by infecting species. 11 patients died while in-patients (19.3%). Independent predictors of death were age ≥ 60 years and a history of convulsions (odds ratios and 95% confidence intervals 8.7 (1 - 76), and 16.1 (1.6 - 161) respectively). Residual visual impairment was common, affecting 25 of 46 survivors (54.3%). Infecting species did not influence clinical phenotype or outcome. The minimum inhibitory concentrations of flucytosine and amphotericin B were significantly higher for C. neoformans var grubii compared with C. gattii (p < 0.001 and p = 0.01 respectively). Conclusion In HIV uninfected individuals in Vietnam, cryptococcal meningitis occurs predominantly in people with no clear predisposing factor and is most commonly due to C. neoformans var grubii. The rates of mortality and visual loss are high and independent of infecting species. There are detectable differences in susceptibility to commonly used antifungal drugs between species, but the clinical significance of this is not clear.
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Affiliation(s)
- Tran Th Chau
- Hospital for Tropical Diseases, Quan, Ho Chi Minh City, Vietnam
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Favalessa OC, Ribeiro LC, Tadano T, Fontes CJF, Dias FB, Coelho BPA, Hahn RC. [First description of phenotypic profile and in vitro drug susceptibility of Cryptococcus spp yeast isolated from HIV-positive and HIV-negative patients in State of Mato Grosso]. Rev Soc Bras Med Trop 2010; 42:661-5. [PMID: 20209351 DOI: 10.1590/s0037-86822009000600010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Accepted: 10/19/2009] [Indexed: 11/21/2022] Open
Abstract
Thirty-seven isolates from 10 HIV-negative and 26 HIV-positive patients in Mato Grosso were evaluated. Direct examination, culturing and chemotyping of species were performed. Ketoconazole, itraconazole, voriconazole, fluconazole and amphotericin B were evaluated. Thirty-seven yeasts of Cryptococcus spp were identified, of which 26 were from HIV-positive patients (25 Cryptococcus neoformans and one Cryptococcus gattii) and 10 from HIV-negative patients (five Cryptococcus neoformans and five Cryptococcus gattii). The Cryptococcus neoformans clinical isolates from HIV-positive patients showed resistance (8% and 8.7%) and dose-dependent susceptibility (20% and 17.4%) to fluconazole and itraconazole, respectively. Among the Cryptococcus neoformans isolates from HIV-negative patients, there was dose-dependent susceptibility (40%) to fluconazole. Cryptococcus gattii isolates from HIV-negative patients were shown to be susceptible to all antifungal agents, except for one isolate of Cryptococcus gattii that showed dose-dependent susceptibility to fluconazole (20%). The Cryptococcus gattii isolate from an HIV-positive patient showed resistance to fluconazole (MIC > or = 256 (1/4)g/ml) and itraconazole (MIC = 3 (1/4)microg/ml).
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Affiliation(s)
- Olivia Cometti Favalessa
- Laboratório de Investigação (Micologia), Faculdade de Ciências Médicas, Universidade Federal de Mato Grosso, Cuiabá, MT
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Abstract
We analyzed 71 clinical and environmental Cryptococcus gattii strains that had been isolated before or after the advent of azole antifungals to determine their level of heteroresistance to fluconazole (LHF). All strains of C. gattii manifested heteroresistance, with LHFs that ranged between 4 microg/ml and 32 microg/ml. A considerably higher proportion of the C. gattii strains (86%) than Cryptococcus neoformans strains (46%) exhibited LHFs that were > or =16 microg/ml. No significant correlation was observed between the molecular type or serotypes of strains and their respective LHF. The strains which expressed a higher LHF were also more resistant to xenobiotics than the strains with a low LHF, and the level of resistance to xenobiotics was significantly higher than that reported for C. neoformans. The heteroresistant subpopulation, whose level of drug resistance had been raised in a stepwise manner to 64 microg/ml, reverted to the original LHF upon daily transfers in drug-free medium. Importantly, the strains with high LHFs were significantly more virulent than those with low LHFs. Since all the clinical isolates that had not been exposed to azole drugs as well as the environmental strains manifested heteroresistance to fluconazole, heteroresistance of C. gattii to azoles is an intrinsic mechanism as in C. neoformans and is associated with the strain's virulence.
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Fera MT, La Camera E, De Sarro A. New triazoles and echinocandins: mode of action, in vitro activity and mechanisms of resistance. Expert Rev Anti Infect Ther 2010; 7:981-98. [PMID: 19803707 DOI: 10.1586/eri.09.67] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Different types of mycoses, especially invasive mycoses caused by yeasts and molds, are a growing problem in healthcare. The most notable explanation for this increase is a rise in the number of immunocompromised patients owing to advances in transplantation, the emergence of AIDS and a rise in the number of invasive surgical procedures. Despite advances in medical practice, some therapeutic problems remain. In addition, intrinsic or acquired antifungal resistance may pose a serious problem to antifungal therapy. A new generation of triazole agents (voriconazole, posaconazole, isavuconazole, ravuconazole and albaconazole) and the recent class of the echinocandins (caspofungin, micafungin and anidulafungin) have become available, and represent an alternative to conventional antifungals for serious fungal infection management. Currently, only two of the recent triazole generation (voriconazole and posaconazole) and all three echinocandins are available for clinical use. More precisely, voriconazole and posaconazole are indicated for the treatment of invasive fungal infections and the echinocandins for the treatment of specific candidiasis. Voriconazole and posaconazole have a very broad spectrum of antifungal activity that includes Candida species, and filamentous and dimorphic fungi. Their activity extends to both fluconazole- and itraconazole-resistant strains of Candida. A major difference between posaconazole and voriconazole is that posaconazole has activity against Zygomycetes including Mucor spp., Rhizopus spp. and Cunninghamella spp., and voriconazole has no activity against this class of fungi. Ravuconazole, isavuconazole and albaconazole have shown very potent in vitro activity against species of Candida, Cryptococcus and Aspergillus, and they are currently in various stages of development. All three echinocandin agents, caspofungin, micafungin and anidulafungin, are similar in their spectrum of activity. Echinocandins do not possess in vitro activity against important basidiomycetes, including Cryptococcus, Rhodotorula and Trichosporon. This review attempts to deliver the most up-to-date knowledge on the mode of action and mechanisms of resistance to triazoles and echinocandins in fungal pathogens. In addition, the in vitro activity data available on triazoles and echinocandins are reported.
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Affiliation(s)
- Maria Teresa Fera
- Dipartimento di Patologia e Microbiologia Sperimentale, Università oli Messina, Policlinico Universitario, Torre Biologica II piano, 98125 Messina, Italy.
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Mazuelos EM, García AIA. Aspectos microbiológicos de la criptococosis en la era post-TARGA. Enferm Infecc Microbiol Clin 2010; 28 Suppl 1:40-5. [DOI: 10.1016/s0213-005x(10)70007-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Correlation of genotype and in vitro susceptibilities of Cryptococcus gattii strains from the Pacific Northwest of the United States. J Clin Microbiol 2009; 48:539-44. [PMID: 20007380 DOI: 10.1128/jcm.01505-09] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cryptococcus gattii emerged in North America in 1999 as a human and veterinary pathogen on Vancouver Island, British Columbia. The emergent subtype, VGIIa, and the closely related subtype VGIIb can now be found in the United States in Washington, Oregon, and California. We performed multilocus sequence typing and antifungal susceptibility testing on 43 isolates of C. gattii from human patients in Oregon, Washington, California, and Idaho. In contrast to Vancouver Island, VGIIa was the most frequent but not the predominant subtype in the northwest United States. Antifungal susceptibility testing showed statistically significant differences in MICs between the subtypes. This is the first study to apply antifungal susceptibility testing to C. gattii isolates from the Pacific Northwest and the first to make direct comparisons between subtypes.
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Identification of Cryptococcus gattii by use of L-canavanine glycine bromothymol blue medium and DNA sequencing. J Clin Microbiol 2009; 47:3669-72. [PMID: 19794048 DOI: 10.1128/jcm.01072-09] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cryptococcus neoformans and Cryptococcus gattii are closely related pathogenic fungi. Cryptococcus neoformans is ecologically widespread and affects primarily immunocompromised patients, while C. gattii is traditionally found in tropical climates and has been reported to cause disease in immunocompetent patients. l-Canavanine glycine bromothymol blue (CGB) agar can be used to differentiate C. neoformans and C. gattii, but there are few reports of its performance in routine clinical practice. Growth of C. gattii on CGB agar produces a blue color, indicating the assimilation of glycine, while C. neoformans fails to cause a color change. Using reference and clinical strains, we evaluated the ability of CGB agar and D2 large ribosomal subunit DNA sequencing (D2 LSU) to differentiate C. neoformans and C. gattii. One hundred two yeast isolates were screened for urease activity, melanin production, and glycine assimilation on CGB agar as well as by D2 sequencing. Seventeen of 17 (100%) C. gattii isolates were CGB positive, and 54 of 54 C. neoformans isolates were CGB negative. Several yeast isolates other than the C. gattii isolates were CGB agar positive, indicating that CGB agar cannot be used alone for identification of C. gattii. D2 correctly identified and differentiated all C. gattii and C. neoformans isolates. This study demonstrates that the use of CGB agar, in conjunction with urea hydrolysis and Niger seed agar, or D2 LSU sequencing can be reliably used in the clinical laboratory to distinguish C. gattii from C. neoformans. We describe how CGB agar and D2 sequencing have been incorporated into the yeast identification algorithm in our laboratory.
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Wiederhold NP. Pharmacology, in vitro activity, and in vivo efficacy of new antifungal agents. CURRENT FUNGAL INFECTION REPORTS 2009. [DOI: 10.1007/s12281-009-0011-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Abstract
Cryptococcus neoformans and Cryptococcus gattii are the cause of life-threatening meningoencephalitis in immunocompromised and immunocompetent individuals respectively. The increasing incidence of cryptococcal infection as a result of the AIDS epidemic, the recent emergence of a hypervirulent cryptococcal strain in Canada and the fact that mortality from cryptococcal disease remains high have stimulated intensive research into this organism. Here we outline recent advances in our understanding of C. neoformans and C. gattii, including intraspecific complexity, virulence factors, and key signaling pathways. We discuss the molecular basis of cryptococcal virulence and the interaction between these pathogens and the host immune system. Finally, we discuss future challenges in the study and treatment of cryptococcosis.
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Affiliation(s)
- Hansong Ma
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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Evaluation of the Neo-Sensitabs diffusion method for determining the antifungal susceptibilities of Cryptococcus gattii isolates, using three different agar media. Rev Iberoam Micol 2009; 25:215-20. [PMID: 19071889 DOI: 10.1016/s1130-1406(08)70052-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Neo-Sensitabs diffusion method was evaluated for determining the antifungal susceptibilities of 30 Cryptococcus gattii isolates to amphotericin B (AMB), fluconazole (FLC), itraconazole (ITC) and voriconazole (VRC). Three different culture media, Müeller-Hinton (MH), RPMI 1640 (RPMI) and Antibiotic medium 3 (AM3), all supplemented with 2% of glucose and 0.5 microg/ml of methylene blue, were tested. The tests were repeated three times on different days at three incubation times (48, 72 and 96 h). Results were compared with those obtained with the CLSI M27-A2 broth microdilution method. The degree of reproducibility of the diffusion test was 100% for VRC and ITC, 98.3-100% for AMB and 43.3-73.3% for FLC. The best reproducibility was observed at 48 h of incubation and no important differences among media were observed at any of the incubation times assayed. Between Neo-Sensitabs and the reference method, VRC showed the best agreement and ITC the worst in all conditions tested (100% and 56.7%, respectively). AMB showed a high agreement between the two methods (93.3% to 96.7%) but Neo-Sensitabs assay failed to detect resistant isolates (discrepancy classified as "very major error") in all times of incubation assayed. Only agreement between both methods for FLC was clearly affected by incubation time and media used, the best results being achieved at 48 h of incubation when MH and RPMI (80.0%, in both media) were used.
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