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McCormick TS, Ghannoum M. Time to Think Antifungal Resistance Increased Antifungal Resistance Exacerbates the Burden of Fungal Infections Including Resistant Dermatomycoses. Pathog Immun 2024; 8:158-176. [PMID: 38486922 PMCID: PMC10939368 DOI: 10.20411/pai.v8i2.656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 02/07/2024] [Indexed: 03/17/2024] Open
Abstract
Increased antifungal resistance is exacerbating the burden of invasive fungal infections, as well as potentially contributing to the increase in resistant dermatomycoses. In this commentary, we focus on antifungal drug resistance, in contrast to antibacterial resistance. We provide a brief historical perspective on the emergence of antifungal resistance and propose measures for combating this growing health concern. The increase in the incidence of invasive and cutaneous fungal infections parallels advancements in medical interventions, such as immunosuppressive drugs, to manage cancer and reduce organ rejection following transplant. A disturbing relatively new trend in antifungal resistance is the observation of several fungal species that now exhibit multidrug resistance (eg, Candida auris, Trichophyton indotineae). Increasing awareness of these multidrug-resistant species is paramount. Therefore, increased education regarding potential fungus-associated infections is needed to address awareness in the general healthcare setting, which may result in a more realistic picture of the prevalence of antifungal-resistant infections. In addition to education, increased use of diagnostic tests (eg, micro and macro conventional assays or molecular testing) should be routine for healthcare providers facing an unknown fungal infection. Two critical barriers that affect the low rates for Antifungal Susceptibility Testing (AST) are low (or a lack of) sufficient insurance reimbursement rates and the low number of qualified laboratories with the capacity to perform AST. The ultimate aim is to improve the quality of patient care through fungal identification, diagnosis, and, where appropriate, susceptibility testing. Here we propose an all-encompassing call to action to address this emerging challenge.
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Affiliation(s)
- Thomas S. McCormick
- Department of Dermatology, Center for Medical Mycology, Case Western Reserve University, Cleveland, Ohio
| | - Mahmoud Ghannoum
- Department of Dermatology, Center for Medical Mycology, Case Western Reserve University, Cleveland, Ohio
- University Hospitals Cleveland Medical Center, Cleveland, Ohio
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2
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McHale TC, Boulware DR, Kasibante J, Ssebambulidde K, Skipper CP, Abassi M. Diagnosis and management of cryptococcal meningitis in HIV-infected adults. Clin Microbiol Rev 2023; 36:e0015622. [PMID: 38014977 PMCID: PMC10870732 DOI: 10.1128/cmr.00156-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023] Open
Abstract
Cryptococcal meningitis is a leading cause of morbidity and mortality globally, especially in people with advanced HIV disease. Cryptococcal meningitis is responsible for nearly 20% of all deaths related to advanced HIV disease, with the burden of disease predominantly experienced by people in resource-limited countries. Major advancements in diagnostics have introduced low-cost, easy-to-use antigen tests with remarkably high sensitivity and specificity. These tests have led to improved diagnostic accuracy and are essential for screening campaigns to reduce the burden of cryptococcosis. In the last 5 years, several high-quality, multisite clinical trials have led to innovations in therapeutics that have allowed for simplified regimens, which are better tolerated and result in less intensive monitoring and management of medication adverse effects. One trial found that a shorter, 7-day course of deoxycholate amphotericin B is as effective as the longer 14-day course and that flucytosine is an essential partner drug for reducing mortality in the acute phase of disease. Single-dose liposomal amphotericin B has also been found to be as effective as a 7-day course of deoxycholate amphotericin B. These findings have allowed for simpler and safer treatment regimens that also reduce the burden on the healthcare system. This review provides a detailed discussion of the latest evidence guiding the clinical management and special circumstances that make cryptococcal meningitis uniquely difficult to treat.
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Affiliation(s)
- Thomas C. McHale
- Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - David R. Boulware
- Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - John Kasibante
- Infectious Diseases Institute, Makerere University, Kampala, Uganda
| | | | - Caleb P. Skipper
- Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Mahsa Abassi
- Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
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3
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de Oliveira L, Melhem MDSC, Buccheri R, Chagas OJ, Vidal JE, Diaz-Quijano FA. Early clinical and microbiological predictors of outcome in hospitalized patients with cryptococcal meningitis. BMC Infect Dis 2022; 22:138. [PMID: 35139801 PMCID: PMC8830130 DOI: 10.1186/s12879-022-07118-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 01/20/2022] [Indexed: 11/10/2022] Open
Abstract
Background Cryptococcal meningitis causes high mortality in immunocompromised and immunocompetent patients. The objective of this study was to identify early predictors of clinical outcome, available at the first days of hospitalization, in patients with cryptococcal meningitis in a tertiary center in Brazil. Methods Ninety-six cases of cryptococcal meningitis with clinical, epidemiological and laboratory data, and identification and antifungal susceptibility of the strains were analyzed. Quantitative CSF yeast counts were performed by direct microscopic exam with a Fuchs-Rosenthal cell counting chamber using an institutional protocol. Univariable and multiple analyses using logistic regression were performed to identify predictors, available at the beginning of hospitalization, of in-hospital mortality. Moreover, we performed a secondary analysis for a composite outcome defined by hospital mortality and intensive care unit transfer. Results The species and the antifungal susceptibility were not associated with the outcomes evaluated. The variables significantly associated with the mortality were age (OR = 1.08, 95% CI 1.02–1.15), the cerebrospinal fluid (CSF) yeasts count (OR = 1.65, 95% CI 1.20–2.27), systemic arterial hypertension (OR = 22.63, 95% CI 1.64–312.91) and neurological impairment identified by computed tomography (OR = 41.73, 95% CI 3.10–561.65). At the secondary analysis, CSF yeast count was also associated with the composite outcome, in addition to the culture of Cryptococcus spp. from bloodstream and cerebral toxoplasmosis. The associations were consistent with survival models evaluated. Conclusions Age and CSF yeast count were independently associated with in-hospital mortality of patients with cryptococcal meningitis but Cryptococcus species identification and antifungal susceptibility were not associated with the outcomes. Quantitative CSF yeast counts used in this study can be evaluated and implemented in other low and middle-income settings. Supplementary Information The online version contains supplementary material available at 10.1186/s12879-022-07118-7.
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Affiliation(s)
- Lidiane de Oliveira
- Department of Epidemiology, School of Public Health, University of São Paulo, Av. Dr. Arnaldo, 715, São Paulo, SP, CEP 01246-904, Brazil.
| | - Marcia de Souza Carvalho Melhem
- Mycology Unit of Adolfo Lutz Institute, Public Health Reference Laboratory, Secretary of Health, Av. Dr.Arnaldo, 351, São Paulo, SP, CEP 05411-000, Brazil.,School of Medicine, Federal University of Mato Grosso do Sul, Bairro Universitário, Av. Costa e Silva, s/no, Campo Grande, MS, CEP 79070-900, Brazil
| | - Renata Buccheri
- Department of Neurology, Emílio Ribas Institute of Infectious Diseases, Av. Dr. Arnaldo 165, São Paulo, SP, CEP 05411-000, Brazil
| | - Oscar José Chagas
- Department of Neurology, Emílio Ribas Institute of Infectious Diseases, Av. Dr. Arnaldo 165, São Paulo, SP, CEP 05411-000, Brazil
| | - José Ernesto Vidal
- Department of Neurology, Emílio Ribas Institute of Infectious Diseases, Av. Dr. Arnaldo 165, São Paulo, SP, CEP 05411-000, Brazil.,Department of Infectious Diseases, Hospital das Clinicas, School of Medicine, University of São Paulo, Av. Dr. Enéas de Carvalho Aguiar, 470, São Paulo, SP, CEP 01246-904, Brazil
| | - Fredi Alexander Diaz-Quijano
- Department of Epidemiology, School of Public Health, University of São Paulo, Av. Dr. Arnaldo, 715, São Paulo, SP, CEP 01246-904, Brazil
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4
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Gerlach ES, Altamirano S, Yoder JM, Luggya TS, Akampurira A, Meya DB, Boulware DR, Rhein J, Nielsen K. ATI-2307 Exhibits Equivalent Antifungal Activity in Cryptococcus neoformans Clinical Isolates With High and Low Fluconazole IC 50. Front Cell Infect Microbiol 2021; 11:695240. [PMID: 34249782 PMCID: PMC8262267 DOI: 10.3389/fcimb.2021.695240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 05/10/2021] [Indexed: 01/16/2023] Open
Abstract
Half maximal inhibitory concentrations (IC50) to the experimental drug ATI-2307 and complete inhibition (IC90) of the common clinically used antifungal drug amphotericin B were determined by microbroth dilution assay for a collection of 69 clinical isolates of Cryptococcus neoformans from Uganda that had high fluconazole IC50 values. The majority of the clinical isolates tested had fluconazole IC50 at or above 8 µg/mL, but were susceptible to both amphotericin B (IC90 ≤1 μg/mL) and ATI-2307 (IC50 ≤0.0312 µg/mL). No correlation between increased fluconazole minimum inhibitory concentration (MIC) and ATI-2307 or amphotericin B MIC was observed, suggesting that the cellular changes impacting fluconazole susceptibility did not impact the effectiveness of ATI-2307. Our results suggest that ATI-2307 is a promising new antifungal drug for use in the context of high fluconazole or other antifungal drug MICs and/or in combination drug therapy regimens.
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Affiliation(s)
- Elliot S. Gerlach
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, United States
| | - Sophie Altamirano
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, United States
| | - J. Marina Yoder
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, United States
| | - Tony S. Luggya
- Infectious Diseases Institute, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Andrew Akampurira
- Infectious Diseases Institute, College of Health Sciences, Makerere University, Kampala, Uganda
| | - David B. Meya
- Infectious Diseases Institute, College of Health Sciences, Makerere University, Kampala, Uganda
| | - David R. Boulware
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Joshua Rhein
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Kirsten Nielsen
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, United States
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5
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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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6
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Vena A, Muñoz P, Guinea J, Escribano P, Peláez T, Valerio M, Bonache F, Gago S, Álvarez-Uría A, Bouza E. Fluconazole resistance is not a predictor of poor outcome in patients with cryptococcosis. Mycoses 2019; 62:441-449. [PMID: 30184276 DOI: 10.1111/myc.12847] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 08/07/2018] [Accepted: 08/30/2018] [Indexed: 01/19/2023]
Abstract
BACKGROUND Cryptococcus isolates with high MICs to fluconazole are increasingly reported, and a potential clinical impact has been advocated. However, there are different methods to evaluate fluconazole MICs and comparative analysis among such techniques and their comprehensive correlation with clinical outcome are not available. METHODS Over a 13-year period (2000-2013), fluconazole MICs were determined for 62 cryptococcal isolates recovered from 22 patients with cryptococcosis using CLSI M27-A3, EUCAST, E test and Sensititre YeastOne, simultaneously. The relationship between the fluconazole MICs and the clinical outcome at week 10 was assessed in patients who received fluconazole as induction or maintenance therapy (n = 16). RESULTS The percentage of cryptococcal strains with MIC values ≥16 μg/mL according to different methods was CLSI 1.6%, EUCAST 16.1%, E test 31.6% and Sensititre YeastOne 53.2%. Among the 16 patients treated with fluconazole, no correlation between clinical outcome and any MIC value obtained with either method was observed. The only variable independently associated with a poor outcome was having a disseminated disease. CONCLUSIONS There is a weak correlation between fluconazole MICs against Cryptococcus spp. as determined by CLSI, EUCAST, E test and Sensititre YeastOne. Neither procedure could predict the clinical outcome of patients with cryptococcosis receiving fluconazole-based therapy. With present methods, fluconazole resistance in Cryptococcus may be clinically misleading.
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Affiliation(s)
- Antonio Vena
- Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,Instituto de Investigación Sanitaria Hospital Gregorio Marañón, Madrid, Spain.,Medicine Department, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain.,Department of Medicine, Infectious Diseases Clinic, University of Udine and Azienda Sanitaria Universitaria Integrata, Udine, Italy
| | - Patricia Muñoz
- Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,Instituto de Investigación Sanitaria Hospital Gregorio Marañón, Madrid, Spain.,Medicine Department, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain.,CIBER Enfermedades Respiratorias-CIBERES, Madrid, Spain
| | - Jesús Guinea
- Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,Instituto de Investigación Sanitaria Hospital Gregorio Marañón, Madrid, Spain
| | - Pilar Escribano
- Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,Instituto de Investigación Sanitaria Hospital Gregorio Marañón, Madrid, Spain
| | - Teresa Peláez
- Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,Instituto de Investigación Sanitaria Hospital Gregorio Marañón, Madrid, Spain
| | - Maricela Valerio
- Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,Instituto de Investigación Sanitaria Hospital Gregorio Marañón, Madrid, Spain
| | - Francisco Bonache
- Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain
| | - Sara Gago
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Madrid, Spain.,Manchester Fungal Infection Group, Institute of Inflammation and Repair, University of Manchester, Manchester, UK
| | - Ana Álvarez-Uría
- Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,Instituto de Investigación Sanitaria Hospital Gregorio Marañón, Madrid, Spain
| | - Emilio Bouza
- Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,Instituto de Investigación Sanitaria Hospital Gregorio Marañón, Madrid, Spain.,Medicine Department, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain.,CIBER Enfermedades Respiratorias-CIBERES, Madrid, Spain
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7
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de Oliveira L, Cristina Silva Santos D, dos Anjos Martins M, Szeszs MW, Souza Carvalho Melhem M. Time-Kill Curves Studies with Amphotericin B Against Cryptococcus neoformans/C. gattii Species Complex Clinical Isolates. CURRENT FUNGAL INFECTION REPORTS 2017. [DOI: 10.1007/s12281-017-0296-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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8
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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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9
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Hagen F, Khayhan K, Theelen B, Kolecka A, Polacheck I, Sionov E, Falk R, Parnmen S, Lumbsch HT, Boekhout T. Recognition of seven species in the Cryptococcus gattii/Cryptococcus neoformans species complex. Fungal Genet Biol 2015; 78:16-48. [PMID: 25721988 DOI: 10.1016/j.fgb.2015.02.009] [Citation(s) in RCA: 473] [Impact Index Per Article: 52.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 02/12/2015] [Accepted: 02/15/2015] [Indexed: 02/08/2023]
Abstract
Phylogenetic analysis of 11 genetic loci and results from many genotyping studies revealed significant genetic diversity with the pathogenic Cryptococcus gattii/Cryptococcus neoformans species complex. Genealogical concordance, coalescence-based, and species tree approaches supported the presence of distinct and concordant lineages within the complex. Consequently, we propose to recognize the current C. neoformans var. grubii and C. neoformans var. neoformans as separate species, and five species within C. gattii. The type strain of C. neoformans CBS132 represents a serotype AD hybrid and is replaced. The newly delimited species differ in aspects of pathogenicity, prevalence for patient groups, as well as biochemical and physiological aspects, such as susceptibility to antifungals. MALDI-TOF mass spectrometry readily distinguishes the newly recognized species.
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Affiliation(s)
- Ferry Hagen
- CBS-KNAW Fungal Biodiversity Centre, Basidiomycete and Yeast Research, Utrecht, The Netherlands; Department of Medical Microbiology and Infectious Diseases, Canisius-Wilhelmina Hospital, Nijmegen, The Netherlands
| | - Kantarawee Khayhan
- CBS-KNAW Fungal Biodiversity Centre, Basidiomycete and Yeast Research, Utrecht, The Netherlands; Department of Microbiology and Parasitology, Faculty of Medical Sciences, University of Phayao, Phayao, Thailand
| | - Bart Theelen
- CBS-KNAW Fungal Biodiversity Centre, Basidiomycete and Yeast Research, Utrecht, The Netherlands
| | - Anna Kolecka
- CBS-KNAW Fungal Biodiversity Centre, Basidiomycete and Yeast Research, Utrecht, The Netherlands
| | - Itzhack Polacheck
- Department of Clinical Microbiology and Infectious Diseases, Hadassah-Hebrew University Medical Center, Ein Kerem, Jerusalem, Israel
| | - Edward Sionov
- Department of Clinical Microbiology and Infectious Diseases, Hadassah-Hebrew University Medical Center, Ein Kerem, Jerusalem, Israel; Department of Food Quality & Safety, Institute for Postharvest and Food Sciences, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel
| | - Rama Falk
- Department of Clinical Microbiology and Infectious Diseases, Hadassah-Hebrew University Medical Center, Ein Kerem, Jerusalem, Israel; Department of Fisheries and Aquaculture, Ministry of Agriculture and Rural Development, Nir-David, Israel
| | - Sittiporn Parnmen
- Department of Medical Sciences, Ministry of Public Health, Nonthaburi, Thailand
| | | | - Teun Boekhout
- CBS-KNAW Fungal Biodiversity Centre, Basidiomycete and Yeast Research, Utrecht, The Netherlands; Shanghai Key Laboratory of Molecular Medical Mycology, Changzheng Hospital, Second Military Medical University, Shanghai, China; Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
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10
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Comparative analysis of the Vitek 2 antifungal susceptibility system and E-test with the CLSI M27-A3 broth microdilution method for susceptibility testing of Indian clinical isolates of Cryptococcus neoformans. Mycopathologia 2012; 173:427-33. [PMID: 22354778 DOI: 10.1007/s11046-012-9528-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Accepted: 02/03/2012] [Indexed: 10/28/2022]
Abstract
The emergence of antifungal resistance among Cryptococcus neoformans isolates is a matter of great concern. The Clinical and Laboratory Standards Institute (CLSI) broth microdilution reference method (BMD) for antifungal susceptibility testing of C. neoformans is tedious and time-consuming. Consequently, there is a greater need for a reproducible in vitro susceptibility testing method for use in clinical microbiology laboratories. By random amplified polymorphic DNA analysis, the 62 Indian clinical isolates were characterized as Cryptococcus neoformans var. grubii. We evaluated the susceptibilities of these isolates for amphotericin B (AMB) and fluconazole (FLC) by two commercial techniques, i.e., Vitek 2 and E-test against the CLSI M27-A3 BMD. The essential agreement (EA) between the Vitek 2 and E-test with the reference procedure for FLC was similar (82.2%). For AMB, EA of 92 and 76% was obtained with E-test and Vitek 2. Excellent categorical agreement (CA) (98.3% and 100% by Vitek 2 and E-test, respectively) was obtained for AMB. The CA for FLC was 81 and 77.4% by Vitek 2 and E-test. We conclude that both E-test and Vitek 2 system have acceptable levels of accuracy for susceptibility testing of both the drugs. Both of them could identify fluconazole-resistant strains. Vitek 2 could be used for testing susceptibility of voriconazole and 5-flucytosine also at the same time.
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11
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Mlinarić-Missoni E, Hagen F, Chew WHM, Važić-Babić V, Boekhout T, Begovac J. In vitro antifungal susceptibilities and molecular typing of sequentially isolated clinical Cryptococcus neoformans strains from Croatia. J Med Microbiol 2011; 60:1487-1495. [DOI: 10.1099/jmm.0.031344-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Affiliation(s)
- Emilija Mlinarić-Missoni
- Croatian National Institute of Public Health, Reference Centre for Diagnostics of Systemic Mycoses, Zagreb, Croatia
| | - Ferry Hagen
- Department of Internal Medicine and Infectious Diseases, University Medical Center, Utrecht, The Netherlands
- CBS Fungal Biodiversity Centre, Department of Yeast and Basidiomycete Research, Utrecht, The Netherlands
| | | | - Verica Važić-Babić
- Croatian National Institute of Public Health, Reference Centre for Diagnostics of Systemic Mycoses, Zagreb, Croatia
| | - Teun Boekhout
- Department of Internal Medicine and Infectious Diseases, University Medical Center, Utrecht, The Netherlands
- CBS Fungal Biodiversity Centre, Department of Yeast and Basidiomycete Research, Utrecht, The Netherlands
| | - Josip Begovac
- Department of Infectious Diseases, University of Zagreb School of Medicine, Zagreb, Croatia
- University Hospital for Infectious Diseases, Zagreb, Croatia
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Trends in antifungal drug susceptibility of Cryptococcus neoformans isolates obtained through population-based surveillance in South Africa in 2002-2003 and 2007-2008. Antimicrob Agents Chemother 2011; 55:2606-11. [PMID: 21444707 DOI: 10.1128/aac.00048-11] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cryptococcus neoformans is the most common cause of meningitis among adult South Africans with HIV infection/AIDS. Widespread use of fluconazole for treatment of cryptococcal meningitis and other HIV-associated opportunistic fungal infections in South Africa may lead to the emergence of isolates with reduced fluconazole susceptibility. MIC testing using a reference broth microdilution method was used to determine if isolates with reduced susceptibility to fluconazole or amphotericin B had emerged among cases of incident disease. Incident isolates were tested from two surveillance periods (2002-2003 and 2007-2008) when population-based surveillance was conducted in Gauteng Province, South Africa. These isolates were also tested for susceptibility to flucytosine, itraconazole, voriconazole, and posaconazole. Serially collected isolate pairs from cases at several large South African hospitals were also tested for susceptibility to fluconazole. Of the 487 incident isolates tested, only 3 (0.6%) demonstrated a fluconazole MIC of ≥ 16 μg/ml; all of these isolates were from 2002-2003. All incident isolates were inhibited by very low concentrations of amphotericin B and exhibited very low MICs to voriconazole and posaconazole. Of 67 cases with serially collected isolate pairs, only 1 case was detected where the isolate collected more than 30 days later had a fluconazole MIC value significantly higher than the MIC of the corresponding incident isolate. Although routine antifungal susceptibility testing of incident isolates is not currently recommended in clinical settings, it is still clearly important for public health to periodically monitor for the emergence of resistance.
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Illnait-Zaragozí MT, Martínez-Machín GF, Fernández-Andreu CM, Hagen F, Boekhout T, Klaassen CHW, Meis JF. Microsatellite typing and susceptibilities of serial Cryptococcus neoformans isolates from Cuban patients with recurrent cryptococcal meningitis. BMC Infect Dis 2010; 10:289. [PMID: 20920321 PMCID: PMC2959061 DOI: 10.1186/1471-2334-10-289] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Accepted: 10/04/2010] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Cryptococcus neoformans is commonly associated with meningoencephalitis in immunocompromised patients and occasionally in apparently healthy individuals. Recurrence of infection after initial treatment is not uncommon. We studied C. neoformans isolates from 7 Cuban patients with recurrent cryptococcal meningitis. Antifungal susceptibility and genotyping with microsatellite molecular typing were carried out. METHODS Isolates (n = 19) were recovered from cerebrospinal fluid, blood, urine and semen. Antifungal susceptibilities for amphotericin B, fluconazole, flucytosine, itraconazole, voriconazole, posaconazole and isavuconazole were tested by CLSI M27A3 broth microdilution method. Genotyping was done using a panel of 9 microsatellite (STR) markers: (CT)n, (TG)n, (TA)n, (CTA)n, (TCT)n, (CCA)n, (TTAT)n, (ATCC)n and (TATT)n. RESULTS The average number of isolates/patient was 2.71. The mean time interval between the collection of any two isolates was 52.5 days. All strains were identified as C. neoformans var. grubii (serotype Aα). Although none of the strains were resistant to the studied drugs, in serial isolates from two patients, MICs values of triazoles increased 4-5 log2 dilutions over time. STR patterns showed 14 distinctive profiles. In three patients the recurrent infection was associated with genotypically identical isolates. The four other patients had relapse isolates which were genotypically different from the initial infecting strain. CONCLUSION Recurrences of cryptococcal meningitis in our series of patients was not associated with development of drug resistance of the original strain but by an initial infection with different strains or a reinfection with a new strain.
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Bii CC, Makimura K, Abe S, Taguchi H, Mugasia OM, Revathi G, Wamae NC, Kamiya S. Antifungal drug susceptibility of Cryptococcus neoformans from clinical sources in Nairobi, Kenya. Mycoses 2007; 50:25-30. [PMID: 17302744 DOI: 10.1111/j.1439-0507.2006.01293.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The serotypes and mating types of 80 clinical isolates of Cryptococcus neoformans from Kenya were studied and subjected to broth microdilution susceptibility testing to amphotericin B (AMP), flucytosin, fluconazole (FLC), itraconazole (ITC) and miconazole (MCZ). The isolates included C. neoformans var. grubii- 75 of 80 (serotype A; 93.7%), C. neoformans var. neoformans- three of 80 (3.8%) and C. neoformans var. gattii- two (serotype B; 2.5%). Mating experiment confirmed all the isolates to be alpha-mating type. Seventy-eight (97.5%) of the isolates had minimum inhibitory concentration (MIC) of < or =0.5 microg ml(-1) to AMP and at 1 microg ml(-1), 100% of the isolates were inhibited. Flucytosin resistance was observed in 21% with MIC in which 90% of the isolates were inhibited (MIC90) of 64 microg ml(-1). Only 23.8% of the strains were susceptible to FLC with 65% susceptible dose-dependent (SDD) and 11.2% resistant. Itraconazole susceptibility was 61.3% while the rest were either SDD or resistant. The MIC90 for ITC and MCZ were 0.5 and 2 microg ml(-1) respectively. The study reports the serotypes, mating types and highlights the existence of azoles resistance in C. neoformans in Nairobi which calls for antifungal drug resistance surveillance as prophylactic use of FLC increases because of human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) epidemic in sub-Saharan Africa.
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Affiliation(s)
- Christine C Bii
- Mycology Laboratory, Center for Microbiology Research, Kenya Medical Research Institute, Nairobi, Kenya.
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15
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Almeida AMF, Matsumoto MT, Baeza LC, de Oliveira E Silva RB, Kleiner AAP, Melhem MDSC, Mendes Giannini MJS. Molecular typing and antifungal susceptibility of clinical sequential isolates of Cryptococcus neoformans from Sao Paulo State, Brazil. FEMS Yeast Res 2007; 7:152-64. [PMID: 17311593 DOI: 10.1111/j.1567-1364.2006.00128.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The antifungal susceptibility profiles and the genetic variability of 83 sequential clinical isolates of Cryptococcus neoformans, including four Cryptococcus gattii isolates, obtained from 38 Sao Paulo AIDS patients with cryptococcal meningitis were assessed by electrophoretic karyotyping and random amplified polymorphic DNA (RAPD) analysis. The majority of the Cryptococcus neoformans isolates were highly susceptible to amphotericin B and fluconazole. Twenty percent of the minimum inhibitory concentration values for amphotericin B varied from 0.5 to 1 micro g mL(-1). For fluconazole, 22% occurred in the range 8-16 mug mL(-1). Sequential isolates from nine patients showed a trend towards lower susceptibility to fluconazole, flucytosine, itraconazole and amphotericin B. The results of molecular typing by electrophoretic karyotyping and RAPD analysis showed the presence of 22 electrophoretic karyotypes (EK) and 15 RAPD profiles that were highly correlated. Our results provided evidence for the occurrence of genetic changes in some strains associated with microevolution during the course of infection. We also observed both microevolution and simultaneous coinfection with two distinct Cryptococcus neoformans strains in one patient. In some patients, we found changed EK- and RAPD patterns in association with increased MIC values.
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Nielsen K, Cox GM, Litvintseva AP, Mylonakis E, Malliaris SD, Benjamin DK, Giles SS, Mitchell TG, Casadevall A, Perfect JR, Heitman J. Cryptococcus neoformans {alpha} strains preferentially disseminate to the central nervous system during coinfection. Infect Immun 2005; 73:4922-33. [PMID: 16041006 PMCID: PMC1201212 DOI: 10.1128/iai.73.8.4922-4933.2005] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Cryptococcus neoformans is a fungal pathogen that has evolved over the past 40 million years into three distinct varieties or sibling species (gattii, grubii, and neoformans). Each variety manifests differences in epidemiology and disease, and var. grubii strains are responsible for the vast majority of human disease. In previous studies, alpha strains were more virulent than congenic a strains in var. neoformans, whereas var. grubii congenic a and alpha strains exhibited equivalent levels of virulence. Here the role of mating type in the virulence of var. grubii was further characterized in a panel of model systems. Congenic var. grubii a and alpha strains had equivalent survival rates when cultured with amoebae, nematodes, and macrophages. No difference in virulence was observed between a and alpha congenic strains in multiple inbred-mouse genetic backgrounds, and there was no difference in accumulations in the central nervous system (CNS) late in infection. In contrast, during coinfections, a and alpha strains are equivalent in peripheral tissues but alpha cells have an enhanced predilection to penetrate the CNS. These studies reveal the first virulence difference between congenic a and alpha strains in the most common pathogenic variety and suggest an explanation for the prevalence of alpha strains in clinical isolates.
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Affiliation(s)
- Kirsten Nielsen
- Department of Molecular Genetics and Microbiology, 322 CARL Building, Research Drive, Duke University Medical Center, Durham, NC 27710, USA
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17
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Orem J, Otieno MW, Banura C, Katongole-Mbidde E, Johnson JL, Ayers L, Ghannoum M, Fu P, Feigal EG, Black J, Whalen C, Lederman M, Remick SC. Capacity building for the clinical investigation of AIDS malignancy in East Africa. ACTA ACUST UNITED AC 2005; 29:133-45. [PMID: 15829373 DOI: 10.1016/j.cdp.2004.10.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2004] [Accepted: 10/08/2004] [Indexed: 11/18/2022]
Abstract
PURPOSE To build capacity in the resource-poor setting to support the clinical investigation and treatment of AIDS-related malignancies in a region of the world hardest hit by the AIDS pandemic. METHODS An initial MEDLINE database search for international collaborative partnerships dedicated to AIDS malignancies in developing countries failed to identify any leads. This search prompted us to report progress on our collaboration in this aspect of the epidemic. Building on the formal Uganda-Case Western Reserve University (Case) Research Collaboration dating back to 1987, established NIH-supported centers of research excellence at Case, and expanding activities in Kenya, scientific and training initiatives, research capital amongst our institutions are emerging to sustain a international research enterprise focused on AIDS and other viral-related malignancies. RESULTS A platform of clinical research trials with pragmatic design has been developed to further enhance clinical care and sustain training initiatives with partners in East Africa and the United States. An oral chemotherapy feasibility trial in AIDS lymphoma is near completion; a second lymphoma trial of byrostatin and vincristine is anticipated and a feasibility trial of indinavir for endemic Kaposi's sarcoma is planned. CONCLUSIONS In the absence of published reports of evolving international partnerships dedicated to AIDS malignancy in resource constrained settings, we feel it important for such progress on similar or related international collaborative pursuits to be published. The success of this effort is realized by the long-term international commitment of the collaborating investigators and institutions to sustain this effort in keeping with ethical and NIH standards for the conduct of research; the provision of formal training of investigators and research personnel on clinical problems our East African partners are faced with in practice and the development of pragmatic clinical trials and therapeutic intervention to facilitate technology transfer and enhance clinical practice.
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Affiliation(s)
- Jackson Orem
- Fogarty AIDS International Training and Research Program, Case School of Medicine, Case Western Reserve University, Cleveland, OH, USA
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18
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Archibald LK, Tuohy MJ, Wilson DA, Nwanyanwu O, Kazembe PN, Tansuphasawadikul S, Eampokalap B, Chaovavanich A, Reller LB, Jarvis WR, Hall GS, Procop GW. Antifungal susceptibilities of Cryptococcus neoformans. Emerg Infect Dis 2004; 10:143-5. [PMID: 15078612 PMCID: PMC3322769 DOI: 10.3201/eid1001.020779] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Susceptibility profiles of medically important fungi in less-developed countries remain uncharacterized. We measured the MICs of amphotericin B, 5-flucytosine, fluconazole, itraconazole, and ketoconazole for Cryptococcus neoformans clinical isolates from Thailand, Malawi, and the United States and found no evidence of resistance or MIC profile differences among the countries.
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Affiliation(s)
- Lennox K Archibald
- Natioanl Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
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Yamazumi T, Pfaller MA, Messer SA, Houston AK, Boyken L, Hollis RJ, Furuta I, Jones RN. Characterization of heteroresistance to fluconazole among clinical isolates of Cryptococcus neoformans. J Clin Microbiol 2003; 41:267-72. [PMID: 12517859 PMCID: PMC149577 DOI: 10.1128/jcm.41.1.267-272.2003] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Strains of Cryptococcus neoformans expressing heteroresistance to fluconazole have been described previously. The present study was conducted to investigate the prevalence of heteroresistance among clinical isolates of C. neoformans and to characterize the heteroresistant phenotypes. A total of 107 clinical isolates of C. neoformans for which the MICs of fluconazole ranged from 0.25 to 32 microg/ml were selected. The isolates were chosen to represent a broad geographic distribution. Of the 107 C. neoformans isolates tested, 4 grew on medium containing fluconazole at concentrations that were four to eight times higher than the MICs for each strain. A fifth isolate, for which the fluconazole MIC was 32 microg/ml, grew on agar with 64 microg of fluconazole per ml. These five isolates (4.7% of the total number) were confirmed to exhibit heteroresistant compositions by population analysis. The degree and frequency of resistance varied among the isolates. Stepwise selection by exposure to fluconazole resulted in subclones of all five strains for which the fluconazole MIC was >64 microg/ml. Subclones of three strains demonstrated a homogeneous population of resistant cells on medium containing 64 microg of fluconazole/ml. The resistance was sensitive to incubation temperature, that is, heteroresistance was demonstrable only at 30 degrees C by agar-based tests, and was reversible through serial transfers on fluconazole-free medium over a period of 8 days. These results suggest that the fluconazole-heteroresistant phenotype of C. neoformans exists in a significant proportion of clinical isolates and that fluconazole resistance can be developed by selection from heteroresistant clones and induction by exposure to fluconazole.
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Affiliation(s)
- T Yamazumi
- Medical Microbiology Division, Department of Pathology, University of Iowa College of Medicine, Iowa City, 52242, USA
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20
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Posteraro B, Sanguinetti M, Sanglard D, La Sorda M, Boccia S, Romano L, Morace G, Fadda G. Identification and characterization of a Cryptococcus neoformans ATP binding cassette (ABC) transporter-encoding gene, CnAFR1, involved in the resistance to fluconazole. Mol Microbiol 2003; 47:357-71. [PMID: 12519188 DOI: 10.1046/j.1365-2958.2003.03281.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Resistance to fluconazole is a possible event during prolonged suppressive drug therapy for cryptococ-cal meningitis, the most frequently encountered life-threatening manifestation of cryptococcosis. The knowledge of this resistance at the molecular level is important for management of cryptococcosis. In order to identify genes involved in azole resistance in Cryptococcus neoformans, a cDNA subtraction library technique was chosen as a strategy. First, a fluconazole-resistant mutant BPY22.17 was obtained from a susceptible clinical isolate BPY22 by in vitro exposure to the drug. Then, a subtractive hybridization procedure was used to compare gene expression between the obtained strains. We identified a cDNA overexpressed in the fluconazole-resistant strain BPY22.17 that was used as a probe to isolate the entire gene in a C. neoformans genomic library. Sequence analysis of this gene identified an ATP Binding Cassette (ABC) transporter-encoding gene called C. neoformans AntiFungal Resistance 1 (CnAFR1). Disruption of CnAFR1 gene in the resistant isolate (BPY22.17) resulted in an enhanced susceptibility of the knock-out mutant cnafr1 against fluconazole, whereas reintroduction of the gene in cnafr1 resulted in restoration of the resistance phenotype, thus confirming that CnAFR1 is involved in fluconazole resistance of C. neoformans. Our findings therefore reveal that an active drug efflux mechanism can be involved in the development of azole resistance in this important human pathogen.
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Affiliation(s)
- Brunella Posteraro
- Istituto Microbiologia, Università Cattolica del S. Cuore, L. go F. Vito, 1, 00168 Rome, Italy
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Yan Z, Li X, Xu J. Geographic distribution of mating type alleles of Cryptococcus neoformans in four areas of the United States. J Clin Microbiol 2002; 40:965-72. [PMID: 11880424 PMCID: PMC120284 DOI: 10.1128/jcm.40.3.965-972.2002] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2001] [Revised: 11/23/2001] [Accepted: 01/01/2002] [Indexed: 11/20/2022] Open
Abstract
To better understand the epidemiology and population structure of Cryptococcus neoformans, we determined mating types for 358 C. neoformans strains isolated through the active surveillance program from 1992 to 1994 in four geographic areas in the United States: San Francisco, California; Georgia; Texas; and Alabama. Two assays were used to determine mating types: (i) crossing with standard laboratory tester strains JEC20 and JEC21 on V8 agar medium; and (ii) PCR with the mating type alpha allele-specific primer of the STE12 gene and with serotype (A and D)- and mating type (a and alpha)-specific primers of the STE20 gene. Using these two methods, we found that this sample consisted of the following: (i) 324 serotype A, mating type (MAT) alpha (Aalpha) strains; (ii) 12 serotype D, alpha (Dalpha) strains; (iii) 14 serotype AD strains with mating type alleles Aa and Dalpha (AaDalpha); (iv) 2 serotype AD strains with mating type alleles Aalpha and Da (AalphaDa); (v) 3 serotype B, alpha (Balpha) strains; and (vi) 3 serotype AD strains but with only one mating type allele. No strain with MATa was found within serotype A, B, or D in this collection. Interestingly, 14 of the 19 serotype AD strains contained the Aa allele at the STE20 locus; 13 of these 14 were from San Francisco. Our results suggest that the environment in San Francisco might contain Aa strains capable of mating with Dalpha strains. In addition, our result demonstrate that the sample from San Francisco had a significantly higher proportion of self-fertile strains than those from the other three areas.
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Affiliation(s)
- Zhun Yan
- Department of Biology, McMaster University, Hamilton, Ontario L8S 4K1, Canada
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22
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Xu J, Onyewu C, Yoell HJ, Ali RY, Vilgalys RJ, Mitchell TG. Dynamic and heterogeneous mutations to fluconazole resistance in Cryptococcus neoformans. Antimicrob Agents Chemother 2001; 45:420-7. [PMID: 11158735 PMCID: PMC90307 DOI: 10.1128/aac.45.2.420-427.2001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Infections with the human pathogenic basidiomycetous yeast Cryptococcus neoformans are often treated with fluconazole. Resistance to this antifungal agent has been reported. This study investigated the patterns of mutation to fluconazole resistance in C. neoformans in vitro. The MIC of fluconazole was measured for 21 strains of C. neoformans. The MICs for these 21 strains differed (0.25 to 4.0 microg/ml), but the strains were selected for this study because they exhibited no growth on plates of yeast morphology agar (YMA) containing 8 microg of fluconazole per ml. To determine their mutation rates, six independent cultures from a single original colony were established for each of the 21 strains. Each culture was then spread densely on a YMA plate with 8 microg of fluconazole per ml. A random set of putative mutants was subcultured, and the MIC of fluconazole was determined for each mutant. The 21 strains evinced significant heterogeneity in their mutation rates. The MICs of the putative mutants ranged widely, from their original MIC to 64 microg of fluconazole per ml. However, for this set of 21 strains, there was no significant correlation between the original MIC for a strain and the mutation rate of that strain; the MIC for the mutant could not be predicted from the original MIC. These results suggest that dynamic and heterogeneous mutational processes are involved in generating fluconazole resistance in C. neoformans.
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Affiliation(s)
- J Xu
- Department of Microbiology, Duke University Medical Center, Durham, North Carolina 27710, USA.
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Pfaller M, Zhang J, Messer S, Tumberland M, Mbidde E, Jessup C, Ghannoum M. Molecular epidemiology and antifungal susceptibility of Cryptococcus neoformans isolates from Ugandan AIDS patients. Diagn Microbiol Infect Dis 1998; 32:191-9. [PMID: 9884835 DOI: 10.1016/s0732-8893(98)00095-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Little is known of the antifungal susceptibility patterns and molecular epidemiology of Cryptococcus neoformans from tropical regions. We studied 164 clinical isolates of C. neofomans from 120 Ugandan AIDS patients with cryptococcal meningitis by analyzing their electrophoretic karyotypes and antifungal susceptibility profiles. Computer-assisted analysis of karyotype patterns was performed to generate dendrograms. MICs of fluconazole and flucytosine were determined by reference methods. A total of 43 distinguishable DNA types were identified among the 164 isolates. Only 30 patients (25%) were infected with their own unique strain of c. neoformans, whereas 75% of the patients shared their infecting strain with at least one other patient. Among 17 patients with more than one CSF isolate of C. neoformans, sequential isolates were identical or highly related in 12 (71%) and were different in five patients (29%). The isolates were susceptible to both fluconazole and flucytosine and there were no instances in which a stepwise increase in either fluconazole or flucytosine MICs was observed among serial isolates. These findings suggest that the epidemiology of cryptococcal disease in AIDS patients from tropical regions may be somewhat different from that observed in more temperate climates.
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Affiliation(s)
- M Pfaller
- Department of Pathology, University of Iowa College of Medicine, Iowa City 52242, USA
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24
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Jessup CJ, Pfaller MA, Messer SA, Zhang J, Tumberland M, Mbidde EK, Ghannoum MA. Fluconazole susceptibility testing of Cryptococcus neoformans: comparison of two broth microdilution methods and clinical correlates among isolates from Ugandan AIDS patients. J Clin Microbiol 1998; 36:2874-6. [PMID: 9738036 PMCID: PMC105080 DOI: 10.1128/jcm.36.10.2874-2876.1998] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We compared the yeast nitrogen base (YNB) broth microdilution method with the National Committee for Clinical Laboratory Standards (NCCLS) M27-A microdilution reference method for measuring the in vitro susceptibility of Cryptococcus neoformans isolates to fluconazole. A total of 149 isolates of C. neoformans var. neoformans from Ugandan AIDS patients was tested by both methods. An overall agreement of 88% between the two microdilution methods was observed. All isolates grew well in both RPMI 1640 and YNB media, and MICs could be read after 48 h of incubation by both methods. The range of fluconazole MICs obtained with the YNB method was broader than that obtained with the NCCLS method. The extended range of MICs provided by the YNB method may be of clinical value, as it appears that the clinical outcome may be better among patients infected with strains inhibited by lower concentrations of fluconazole as determined by the YNB method. The YNB method appears to be a viable option for testing C. neoformans against fluconazole.
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Affiliation(s)
- C J Jessup
- Mycology Reference Laboratory, Center for Medical Mycology, Department of Dermatology, Case Western Reserve University and University Hospitals of Cleveland, Ohio, USA
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