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H Albehaijani S, Huynh T, Boyce KJ. Cellular and genetic changes during and after fluconazole exposure in Cryptococcus neoformans. Int J Antimicrob Agents 2025; 66:107519. [PMID: 40252781 DOI: 10.1016/j.ijantimicag.2025.107519] [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: 09/01/2024] [Revised: 04/03/2025] [Accepted: 04/10/2025] [Indexed: 04/21/2025]
Abstract
The validity of genome replication is fundamental to fungal survival, and errors in this process can result in ploidy changes. These changes can have negative effects, such as developmental defects or reduced fitness, or positive effects such as fungal adaptation and resilience. In the fungal pathogen Cryptococcus neoformans, ploidy changes have been consistently observed in clinical populations, and isolates exposed to the antifungal drug fluconazole commonly exhibit chromosome 1 aneuploidy. Chromosomal and putative metabolic function changes due to drug exposure are not well studied and are important for understanding resistance. OBJECTIVES This study examined the fluconazole influence on C. neoformans transient aneuploidy and identified any potential genetic pathways that may be implicated. METHODS The study investigated 30 genes predicted to have a role in transient aneuploidy, which are related to chromosome organisation, DNA damage checkpoints and stress signalling. Other factors including ploidy status (haploid, diploid, polyploid) and species were also investigated to observe commonalities for a universal drug treatment strategy. RESULTS Fluconazole treatment increased DNA content, cell size and chromosomal changes in the wildtype and mutants. When fluconazole was removed, permanent changes were observed and were highly variable in the wildtypes and the 30 mutants. Additionally, some mutants lacked chromosomal changes such as tel1∆, mrc1∆ and hog1∆, highlighting the potential involvement in the aneuploidy process. CONCLUSIONS These findings highlight that fluconazole influences the entire genome rather than specific chromosomes, which increases the heterogeneity in permanent changes after fluconazole removal. This heterogeneity may result in long-term consequences, including drug resistance.
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Affiliation(s)
- Samah H Albehaijani
- School of Science, RMIT University, Melbourne, Victoria, Australia; Department of Biology, College of Science, Qassim University, Buraydah, Saudi Arabia
| | - Tien Huynh
- School of Science, RMIT University, Melbourne, Victoria, Australia.
| | - Kylie J Boyce
- School of Science, RMIT University, Melbourne, Victoria, Australia
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Moreira IDMB, de Sousa NSO, de Almeida JDR, Rosas RLL, Cruz KS, Matsuura ABJ, Melhem MDSC, de Souza ÉS, Frickmann H, Lacerda MVG, de Souza JVB. Fluconazole Resistance and Heteroresistance in Cryptococcus spp.: Mechanisms and Implications. Rev Soc Bras Med Trop 2025; 58:e002002025. [PMID: 40136153 PMCID: PMC11941007 DOI: 10.1590/0037-8682-0328-2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2024] [Accepted: 01/24/2025] [Indexed: 03/27/2025] Open
Abstract
The reference methodology for evaluating antifungal susceptibility is based on determining the minimum inhibitory concentration (MIC), which is the lowest drug concentration capable of inhibiting fungal growth. However, such MIC data are insufficient to measure antifungal susceptibility if a strain is heteroresistant to the tested drug. In such cases, a minority subpopulation of fungal cells, originating from an initially susceptible lineage, can grow at antifungal drug concentrations above the MIC. In studies on fluconazole heteroresistance in Cryptococcus spp., chromosomal disomy has been shown to result in the overexpression of two genes located on chromosome 1 (Chr1) linked to antifungal resistance: ERG11 and AFR1. This review addresses the underlying mechanisms of antifungal resistance, the evolution of methods for determining antifungal susceptibility, and the clinical implications of Cryptococcus heteroresistance to fluconazole. The analysis of the findings indicated a correlation between heteroresistance and adverse clinical outcomes, although this observation still lacks definite confirmation in the literature. This highlights the need to implement more efficient therapeutic strategies and improve antifungal susceptibility and heteroresistance testing.
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Affiliation(s)
| | | | | | | | - Katia Santana Cruz
- Fundação de Medicina Tropical Dr. Heitor Vieira Dourado, Manaus, AM, Brasil
| | | | - Márcia de Souza Carvalho Melhem
- Faculdade de Medicina, PPG Doenças Infecciosas e Parasitárias, UFMS, Campo Grande, MS, Brasil
- Faculdade de Medicina, PPG Doenças Tropicais, Unesp, Botucatu, SP, Brasil
- Instituto de Medicina Tropical de São Paulo, LIM 53, São Paulo, SP, Brasil
| | - Érica Simplício de Souza
- Programa de Pós-Graduação em Biodiversidade e Biotecnologia da Rede BIONORTE, Manaus, AM, Brasil
| | - Hagen Frickmann
- Bundeswehr Hospital Hamburg, Department of Microbiology and Hospital Hygiene, Germany
- University Medicine Rostock, Institute for Medical Microbiology, Virology and Hygiene, Germany
| | - Marcus Vinícius Guimarães Lacerda
- Fundação de Medicina Tropical Dr. Heitor Vieira Dourado, Manaus, AM, Brasil
- Instituto Leônidas & Maria Deane, Fiocruz, Manaus, AM, Brasil
- University of Texas Medical Branch, Galveston, USA
| | - João Vicente Braga de Souza
- Programa de Pós-Graduação em Biodiversidade e Biotecnologia da Rede BIONORTE, Manaus, AM, Brasil
- Instituto Nacional de Pesquisas da Amazônia, Manaus, AM, Brasil
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Duarte I, Rodrigues ML. Funding for research on cryptococcal disease: an analysis based on the G-finder report. IMA Fungus 2024; 15:4. [PMID: 38429837 PMCID: PMC10908028 DOI: 10.1186/s43008-023-00133-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 11/13/2023] [Indexed: 03/03/2024] Open
Abstract
Members of the genus Cryptococcus are the causative agents of cryptococcal meningitis, a disease mainly associated with HIV-induced immunosuppression. Patients with cryptococcal meningitis are at a serious risk of death. Most patients suffering from cryptococcosis belong to neglected populations. With reduced support for research, new therapies are unlikely to emerge. In this essay, we used the Policy Cures/G-finder platform as a reference database for funding research on cryptococcal disease. Funding for cryptococcal research started being tracked by G-finder in 2013 and has continued to appear in the annual reports ever since. In total, 15 institutions were reported as major funders for research on cryptococcal disease over the years. The US National Institutes of Health (NIH) was the main funder, followed by the UK's Wellcome Trust. The annual analysis suggested slow yearly growth in funding from 2013 to 2021. The development of new tools to prevent and fight cryptococcal disease is urgent but requires improved funding.
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Affiliation(s)
- Iraine Duarte
- Instituto Carlos Chagas, Fundação Oswaldo Cruz (Fiocruz), Rua Professor Algacyr Munhoz Mader 3775- CIC, Curitiba, PR, 81350-010, Brazil
| | - Marcio L Rodrigues
- Instituto Carlos Chagas, Fundação Oswaldo Cruz (Fiocruz), Rua Professor Algacyr Munhoz Mader 3775- CIC, Curitiba, PR, 81350-010, Brazil.
- Instituto de Microbiologia Paulo de Góes (IMPG), Universidade Federal do Rio de Janeiro. Cidade Universitária, Centro de Ciências da Saúde., Rio de Janeiro, RJ, 21941-902, Brazil.
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Melhem MSC, Leite Júnior DP, Takahashi JPF, Macioni MB, de Oliveira L, de Araújo LS, Fava WS, Bonfietti LX, Paniago AMM, Venturini J, Espinel-Ingroff A. Antifungal Resistance in Cryptococcal Infections. Pathogens 2024; 13:128. [PMID: 38392866 PMCID: PMC10891860 DOI: 10.3390/pathogens13020128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 01/20/2024] [Accepted: 01/22/2024] [Indexed: 02/25/2024] Open
Abstract
Antifungal therapy, especially with the azoles, could promote the incidence of less susceptible isolates of Cryptococcus neoformans and C. gattii species complexes (SC), mostly in developing countries. Given that these species affect mostly the immunocompromised host, the infections are severe and difficult to treat. This review encompasses the following topics: 1. infecting species and their virulence, 2. treatment, 3. antifungal susceptibility methods and available categorical endpoints, 4. genetic mechanisms of resistance, 5. clinical resistance, 6. fluconazole minimal inhibitory concentrations (MICs), clinical outcome, 7. environmental influences, and 8. the relevance of host factors, including pharmacokinetic/pharmacodynamic (PK/PD) parameters, in predicting the clinical outcome to therapy. As of now, epidemiologic cutoff endpoints (ECVs/ECOFFs) are the most reliable antifungal resistance detectors for these species, as only one clinical breakpoint (amphotericin B and C. neoformans VNI) is available.
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Affiliation(s)
- Marcia S. C. Melhem
- Graduate Program in Sciences, Secretary of Health, São Paulo 01246-002, SP, Brazil; (D.P.L.J.); (M.B.M.)
- Graduate Program in Infectious and Parasitic Diseases, Federal University of Mato Grosso do Sul, Campo Grande 79070-900, MS, Brazil; (J.P.F.T.); (W.S.F.); (A.M.M.P.)
- Graduate Program in Tropical Diseases, State University of São Paulo, Botucatu 18618-687, SP, Brazil
| | - Diniz Pereira Leite Júnior
- Graduate Program in Sciences, Secretary of Health, São Paulo 01246-002, SP, Brazil; (D.P.L.J.); (M.B.M.)
| | - Juliana P. F. Takahashi
- Graduate Program in Infectious and Parasitic Diseases, Federal University of Mato Grosso do Sul, Campo Grande 79070-900, MS, Brazil; (J.P.F.T.); (W.S.F.); (A.M.M.P.)
- Pathology Division, Adolfo Lutz Institute, São Paulo 01246-002, SP, Brazil
| | - Milena Bronze Macioni
- Graduate Program in Sciences, Secretary of Health, São Paulo 01246-002, SP, Brazil; (D.P.L.J.); (M.B.M.)
| | | | - Lisandra Siufi de Araújo
- Graduate Program in Infectious and Parasitic Diseases, Federal University of Mato Grosso do Sul, Campo Grande 79070-900, MS, Brazil; (J.P.F.T.); (W.S.F.); (A.M.M.P.)
- Central Public Health Laboratory-LACEN, Mycology Unit, Adolfo Lutz Institut, São Paulo 01246-002, SP, Brazil;
| | - Wellington S. Fava
- Graduate Program in Infectious and Parasitic Diseases, Federal University of Mato Grosso do Sul, Campo Grande 79070-900, MS, Brazil; (J.P.F.T.); (W.S.F.); (A.M.M.P.)
| | - Lucas X. Bonfietti
- Central Public Health Laboratory-LACEN, Mycology Unit, Adolfo Lutz Institut, São Paulo 01246-002, SP, Brazil;
| | - Anamaria M. M. Paniago
- Graduate Program in Infectious and Parasitic Diseases, Federal University of Mato Grosso do Sul, Campo Grande 79070-900, MS, Brazil; (J.P.F.T.); (W.S.F.); (A.M.M.P.)
| | - James Venturini
- Graduate Program in Infectious and Parasitic Diseases, Federal University of Mato Grosso do Sul, Campo Grande 79070-900, MS, Brazil; (J.P.F.T.); (W.S.F.); (A.M.M.P.)
| | - Ana Espinel-Ingroff
- Central Public Health Laboratory-LACEN, Campo Grande 79074-460, MS, Brazil;
- VCU Medical Center, Richmond, VA 23284, USA
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