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Tan XT, Mokhtar NNB, Hii S, Amran F. Antifungal Susceptibility and Genotypic Analysis of cyp51A Mutations in Aspergillus fumigatus Isolates in Malaysia. Infect Drug Resist 2024; 17:2159-2168. [PMID: 38828376 PMCID: PMC11144424 DOI: 10.2147/idr.s452619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 04/09/2024] [Indexed: 06/05/2024] Open
Abstract
Purpose Azole resistance in Aspergillus fumigatus poses a significant challenge in the management of invasive aspergillosis. This study aimed to investigate the antifungal susceptibility and cyp51A mutation profiles of A. fumigatus isolates in Malaysia. Patients and Methods Sixty clinical A. fumigatus isolates were collected and subjected to antifungal susceptibility testing (AFST) and molecular analysis. The antifungal susceptibility testing was performed according to CLSI M38 guideline. The geometric mean (GM) minimum inhibitory concentration (MIC), MIC50/MIC90 for voriconazole, itraconazole, posaconazole, amphotericin B, and isavuconazole against A. fumigatus in non-invasive cases and invasive cases were calculated. In addition, the presence of cyp51A mutations was also identified. Results The present study revealed an overall resistance rate of 6.7% among the isolates. In non-invasive cases, isavuconazole and posaconazole demonstrated the lowest GM MIC of 0.08 µg/mL. Following them were itraconazole, voriconazole, and amphotericin B with concentrations of 0.15µg/mL, 0.16µg/mL and 0.90µg/mL, respectively. Similarly, in invasive cases, isavuconazole and posaconazole exhibited the lowest GM MIC of 0.09µg/mL. Following them were itraconazole, voriconazole, and amphotericin B with concentrations of 0.14µg/mL, 0.17µg/mL and 0.80µg/mL, respectively. Genotypic analysis revealed various cyp51A mutations, including F46Y, M172V, N248K, R34L, V244A, V244S, and E427K. However, not all mutations corresponded to antifungal resistance. Conclusion The majority of clinical Aspergillus fumigatus isolates demonstrated susceptibility to the antifungal agents tested, with isavuconazole and posaconazole demonstrating the lowest MIC values. However, cyp51A mutations were discovered without a consistent correlation to antifungal resistance, emphasising the need for additional research.
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Affiliation(s)
- Xue Ting Tan
- Bacteriology Unit, Infectious Diseases Research Centre, Institute for Medical Research, National Institute of Health, Ministry of Health Malaysia, Setia Alam, Selangor, Malaysia
| | - Nurin Nazirah Binti Mokhtar
- Bacteriology Unit, Infectious Diseases Research Centre, Institute for Medical Research, National Institute of Health, Ministry of Health Malaysia, Setia Alam, Selangor, Malaysia
| | - Shirley Yi Fen Hii
- Bacteriology Unit, Infectious Diseases Research Centre, Institute for Medical Research, National Institute of Health, Ministry of Health Malaysia, Setia Alam, Selangor, Malaysia
| | - Fairuz Amran
- Bacteriology Unit, Infectious Diseases Research Centre, Institute for Medical Research, National Institute of Health, Ministry of Health Malaysia, Setia Alam, Selangor, Malaysia
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Zheng H, Mei H, Li X, Li D, Liu W. Proteome-Wide Analysis of Lysine 2-Hydroxyisobutyrylation in Aspergillus fumigatus. Curr Microbiol 2024; 81:74. [PMID: 38253771 PMCID: PMC10803526 DOI: 10.1007/s00284-023-03565-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 11/17/2023] [Indexed: 01/24/2024]
Abstract
Aspergillus fumigatus is the significant causative agent in cases of invasive aspergillosis, leading to a high mortality rate in immunocompromised patients. A comprehensive understanding of its growth patterns and metabolic processes within the host is a critical prerequisite for the development of effective antifungal strategies. Lysine 2-hydroxyisobutyrylation (Khib) is a highly conserved protein posttranslational modifications (PTM) found in various organisms. In this study, we investigate the biological impact of Khib in A. fumigatus. Using a combination of antibody enrichment with the conventional LC-MS/MS method, the pattern of Khib-modification in proteins and their respective sites were analyzed in a wild type strain of A. fumigatus. Our findings revealed 3494 Khib-modified proteins with a total of 18,091 modified sites in this strain. Functional enrichment analysis indicated that these Khib-modified proteins participate in a diverse range of cellular functions, spanning various subcellular locations such as ribosome biosynthesis, protein synthesis and nucleocytoplasmic transport. Notably, when compared with other reported eukaryotes, A. fumigatus exhibited consistently higher numbers of Khib-modified proteins, suggesting the potential significance of this modification in this organism. An interesting observation is the prevalence of Khib modifications in most enzymes involved in the ergosterol synthesis pathway. The insights gathered from this study provide new avenue for studying PTM-associated mechanisms in fungal growth and offer potential implication for antifungal drug development.
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Affiliation(s)
- Hailin Zheng
- Department of Medical Mycology, Institute of Dermatology, Chinese Academy of Medical Science and Peking Union Medical College, Nanjing, 210042, Jiangsu, People's Republic of China
- Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, 210042, Jiangsu, People's Republic of China
| | - Huan Mei
- Department of Medical Mycology, Institute of Dermatology, Chinese Academy of Medical Science and Peking Union Medical College, Nanjing, 210042, Jiangsu, People's Republic of China
| | - Xiaofang Li
- Department of Medical Mycology, Institute of Dermatology, Chinese Academy of Medical Science and Peking Union Medical College, Nanjing, 210042, Jiangsu, People's Republic of China
- Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, 210042, Jiangsu, People's Republic of China
| | - Dongmei Li
- Department of Microbiology & Immunology, Georgetown University Medical Center, Washington, DC, 20057, USA
| | - Weida Liu
- Department of Medical Mycology, Institute of Dermatology, Chinese Academy of Medical Science and Peking Union Medical College, Nanjing, 210042, Jiangsu, People's Republic of China.
- Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, 210042, Jiangsu, People's Republic of China.
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Khan S, Bilal H, Shafiq M, Zhang D, Awais M, Chen C, Khan MN, Wang Q, Cai L, Islam R, Zeng Y. Distribution of Aspergillus species and risk factors for aspergillosis in mainland China: a systematic review. Ther Adv Infect Dis 2024; 11:20499361241252537. [PMID: 38835831 PMCID: PMC11149451 DOI: 10.1177/20499361241252537] [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: 09/25/2023] [Accepted: 04/17/2024] [Indexed: 06/06/2024] Open
Abstract
Background Aspergillus, a widespread fungus in the natural environment, poses a significant threat to human health by entering the human body via the airways and causing a disease called aspergillosis. This study comprehensively analyzed data on aspergillosis in published articles from mainland China to investigate the prevalence of Aspergillus, and risk factors, mortality rate, and underlying condition associated with aspergillosis. Methods Published articles were retrieved from Google Scholar, PubMed, and Science Direct online search engines. In the 101 analyzed studies, 3558 Aspergillus isolates were meticulously collected and classified. GraphPad Prism 8 was used to statistically examine the epidemiology and clinical characteristics of aspergillosis. Results Aspergillus fumigatus was prominently reported (n = 2679, 75.14%), followed by A. flavus (n = 437, 12.25%), A. niger (n = 219, 6.14%), and A. terreus (n = 119, 3.33%). Of a total of 9810 patients, 7513 probable cases accounted for the highest number, followed by confirmed cases (n = 1956) and possible cases (n = 341). In patients, cough emerged as the most common complaint (n = 1819, 18.54%), followed by asthma (n = 1029, 10.48%) and fever (1024, 10.44%). Of total studies, invasive pulmonary aspergillosis (IPA) was reported in 47 (45.53%) studies, exhibiting an increased prevalence in Beijing (n = 12, 25.53%), Guangdong (n = 7, 14.89%), and Shanghai (n = 6, 12.76%). Chronic pulmonary aspergillosis (CPA) was reported in 14 (13.86%) studies. Among the total of 14 studies, the occurrence of CPA was 5 (35.71%) in Beijing and 3 (21.42%) in Shanghai. Allergic bronchopulmonary aspergillosis (ABPA), was reported at a lower frequency (n = 8, 7.92%), Guangdong recorded a relatively high number (n = 3, 37.5%), followed by Beijing (n = 2, 25.0%), and Shanghai (n = 1, 12.5%). Percentage of death reported: IPA had the highest rate (n = 447, 68.87%), followed by CPA (n = 181, 27.88%) and ABPA (n = 14, 2.15%). Among the aspergillosis patients, 6220 had underlying conditions, including chronic lung disease (n = 3765, 60.53%), previous tuberculosis (n = 416, 6.68%), and organ transplant or organ failure (n = 648, 10.41%). Aspergillosis was also found in patients using corticosteroid therapy (n = 622, 10.0%). Conclusion This review sheds light on the prevalence patterns of Aspergillus species, risk factors of aspergillosis, and gaps in surveillance that could be helpful for the control and treatment of aspergillosis and guide the researchers in future studies. Registration This systematic review was prospectively registered on PROSPERO: Registration ID CRD42023476870.
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Affiliation(s)
- Sabir Khan
- Department of Dermatology, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Hazrat Bilal
- Department of Dermatology, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Muhammad Shafiq
- Department of Pharmacology, Shantou University Medical College, Shantou, China
| | - Dongxing Zhang
- Department of Dermatology, Meizhou Dongshan Hospital, Meizhou, Guangdong, China
- Department of Dermatology, Meizhou People's Hospital, Meizhou, Guangdong, China
| | - Muhammad Awais
- Department of Environmental Science, Kunming University of Science and Technology, Yunnan, China
| | - Canhua Chen
- Clinical Laboratory, Meizhou People's Hospital, Meizhou, Guangdong, China
| | - Muhammad Nadeem Khan
- Faculty of Biological Sciences, Department of Microbiology, Quaid-i-Azam University, Islamabad, Pakistan
| | - Qian Wang
- Department of Dermatology, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China
- Department of Medical-Surgical and Experimental Sciences, University of Sassari - Neurology Unit, Azienza Ospedaliera Universitaria (AOU) Sassari, Sassari, Italy
| | - Lin Cai
- Department of Dermatology, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Rehmat Islam
- Key Laboratory of Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China
| | - Yuebin Zeng
- Department of Dermatology, West China Second University Hospital, Sichuan University, Chengdu, Sichuan 610021, China
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Lin H, Guo J, Li Y, Xiao C, Hu L, Chen H, Lu X, Wu W. In vitro antifungal susceptibility profile and genotypic characterization of clinical Aspergillus isolates in Eastern China on behalf of Eastern China Invasive Fungi Infection Group. Med Mycol 2023; 61:myad082. [PMID: 37580143 DOI: 10.1093/mmy/myad082] [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: 04/13/2023] [Revised: 07/27/2023] [Accepted: 08/11/2023] [Indexed: 08/16/2023] Open
Abstract
Aspergillus species is a widespread environmental mould that can cause aspergillosis. The purpose of this study was to investigate the antifungal susceptibility profile and genotypic characterization of clinical Aspergillus isolates from different provinces in Eastern China. The data included the antifungal susceptibility distributions with eight common antifungal drugs, cyp51A gene mutations of triazole-resistant Aspergillus fumigatus sensu stricto, and the genotypic relationships among the A. fumigatus sensu stricto isolates based on microsatellite typing. A. fumigatus sensu lato was the most common clinical Aspergillus species (n = 252), followed by A. flavus (n = 169), A. terreus (n = 37), A. niger (n = 29), and A. nidulans (n = 4). The modal minimum effective concentration values of micafungin and anidulafungin were lower than those of caspofungin for all Aspergillus species. The in vitro efficacy of isavuconazole was similar to that of voriconazole against most Aspergillus species. Sequencing revealed cyp51A gene mutations TR34/L98H, TR34/L98H/S297T/F495I, and TR46/Y121F/T289A in four triazole-resistant A. fumigatus sensu stricto. Phylogenetic analyses using microsatellite markers of A. fumigatus sensu stricto revealed that 211 unique genotypes clustered into two clades. The data demonstrate the diversity of clinically relevant Aspergillus species in Eastern China. Routine antifungal susceptibility testing should be performed to monitor the antifungal resistance and guide clinical therapy.
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Affiliation(s)
- Huiping Lin
- Department of Laboratory Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200123, China
| | - Jian Guo
- Department of Laboratory Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200123, China
| | - Yueting Li
- Department of Laboratory Medicine, Jiangxi provincial People's Hospital Affiliated to Nanchang University, Nanchang 330006, China
| | - Chenlu Xiao
- Department of Clinical Microbiology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, 200025, China
| | - Liang Hu
- Department of Laboratory Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200123, China
| | - Hui Chen
- Department of Laboratory Medicine, Jiangxi provincial People's Hospital Affiliated to Nanchang University, Nanchang 330006, China
| | - Xiuhai Lu
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Shandong, 250000, China
| | - Wenjuan Wu
- Department of Laboratory Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200123, China
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Wei T, Zheng N, Zheng H, Chen Y, Hong P, Liu W, Liu M. Proteomic Perspective of Azole Resistance in Aspergillus fumigatus Biofilm Extracellular Matrix in Response to Itraconazole. Med Mycol 2022; 60:myac084. [PMID: 36243954 DOI: 10.1093/mmy/myac084] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Azole-resistant Aspergillus fumigatus makes a major challenge to the chemotherapy for invasive aspergillosis, whereas cyp51A gene mutation is the most dominant mechanism for azole resistance. Moreover, biofilm contributes to drug resistance for A. fumigatus, and extracellular matrix (ECM) is essential to protect live cells from antifungal drugs. Therefore, we performed a comparative proteomic study on the biofilm ECM of both the wild-type and azole-resistant strains of A. fumigatus under azole pressure. In total, 2377 proteins were identified, of which 480 and 604 proteins with differential expression were obtained from the wild-type and azole-resistant A. fumigatus in exposure to itraconazole respectively (fold change > 2 or < 0.5, P-value < 0.05). We found that a high proportion of regulated proteins were located in cytoplasm, nucleus, and mitochondria. Meanwhile, GO and KEGG analyses revealed that metabolic process and ribosome pathway were significantly enriched. Particularly, differentially expressed proteins in response to azole pressure of both the wild-type and resistant strains were further analyzed. Our results indicated that these changes in biofilm ECM proteins were related to ergosterol synthesis, oxidative stress, efflux pumps, DNA repair, DNA replication, and transcription.
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Affiliation(s)
- Tianqi Wei
- Institute of Dermatology, Chinese Academy of Medical Science and Peking Union Medical College, Nanjing, China
| | - Nan Zheng
- Medical School, Nanjing University, Nanjing, China
| | - Hailin Zheng
- Institute of Dermatology, Chinese Academy of Medical Science and Peking Union Medical College, Nanjing, China
| | - Yuping Chen
- Institute of Dermatology, Chinese Academy of Medical Science and Peking Union Medical College, Nanjing, China
| | - Pianpian Hong
- Institute of Dermatology, Chinese Academy of Medical Science and Peking Union Medical College, Nanjing, China
| | - Weida Liu
- Institute of Dermatology, Chinese Academy of Medical Science and Peking Union Medical College, Nanjing, China
- Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
- Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, China
| | - Musang Liu
- Institute of Dermatology, Chinese Academy of Medical Science and Peking Union Medical College, Nanjing, China
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Hsu TH, Huang PY, Fan YC, Sun PL. Azole Resistance and cyp51A Mutation of Aspergillus fumigatus in a Tertiary Referral Hospital in Taiwan. J Fungi (Basel) 2022; 8:jof8090908. [PMID: 36135633 PMCID: PMC9504549 DOI: 10.3390/jof8090908] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 08/20/2022] [Accepted: 08/24/2022] [Indexed: 01/30/2023] Open
Abstract
Azole resistance in Aspergillus fumigatus has increasingly been reported worldwide. Its major mechanism of resistance is mediated by mutations in cyp51A. The objective of this study was to test the antifungal susceptibilities of A. fumigatus isolates from Chang Gung Memorial Hospital (CGMH), the largest tertiary referral hospital in Taiwan, and to investigate cyp51A mutations in azole-resistant strains. A. fumigatus isolates preserved in the Research Laboratory of Medical Mycology of CGMH from 2015 to 2021 were used. Antifungal susceptibility testing was performed using the YeastOneTM method. Isolates with high minimal inhibitory concentrations (MICs) against antifungals were further tested using the Clinical and Laboratory Standards Institute (CLSI) broth microdilution method. Mutations in the cyp51A in azole-resistant strains were detected by Sanger sequencing. The overall prevalence of azole-resistant isolates was 1.77% (two out of 113 isolates). The two azole-resistant strains had tandem repeats (TR) in the promoter region and mutations in the cyp51A gene (TR34/L98H and TR34/L98H/S297T/F495I). One strain showed intermediate susceptibility to voriconazole, and its Cyp51A protein had five amino acid substitutions (F46Y/M172V/N248T/D255E/E427K). TR34/L98H and TR34/L98H/S297T/F495I are the most prevalent cyp51A mutations in Taiwan, mediating azole resistance based on current publications and our results. YeastOneTM was validated as a rapid tool for the antifungal susceptibility test; however, further confirmation by CLSI should be considered when MIC values of voriconazole, posaconazole, and amphotericin B are close to the clinical breakpoints or ecological cutoff values.
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Affiliation(s)
- Tsun-Hao Hsu
- Department of Dermatology, Chang Gung Memorial Hospital, Linkou Branch, Taoyuan 333423, Taiwan
| | - Po-Yen Huang
- Division of Infectious Diseases, Department of Internal Medicine, Chang Gung Memorial Hospital, Linkou Branch, Taoyuan 333423, Taiwan
- College of Medicine, Chang Gung University, Taoyuan 333323, Taiwan
| | - Yun-Chen Fan
- Research Laboratory of Medical Mycology, Chang Gung Memorial Hospital, Linkou Branch, Taoyuan 333423, Taiwan
| | - Pei-Lun Sun
- Department of Dermatology, Chang Gung Memorial Hospital, Linkou Branch, Taoyuan 333423, Taiwan
- College of Medicine, Chang Gung University, Taoyuan 333323, Taiwan
- Research Laboratory of Medical Mycology, Chang Gung Memorial Hospital, Linkou Branch, Taoyuan 333423, Taiwan
- Correspondence: ; Tel.: +886-3-328-1200 (ext. 8778)
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7
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Wang Y, Zhang L, Zhou L, Zhang M, Xu Y. Epidemiology, Drug Susceptibility, and Clinical Risk Factors in Patients With Invasive Aspergillosis. Front Public Health 2022; 10:835092. [PMID: 35493371 PMCID: PMC9051236 DOI: 10.3389/fpubh.2022.835092] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 03/04/2022] [Indexed: 11/13/2022] Open
Abstract
BackgroundThis study aimed to investigate the Aspergillus species distribution, antifungal sensitivities, clinical characteristics, and risk factors of patients with invasive aspergillosis (IA) in a tertiary teaching hospital in Anhui Province.MethodsIn the present study, 156 Aspergillus isolates were collected from patients admitted to a 2,800-bed comprehensive hospital between January 2019 and April 2021. The epidemiology of Aspergillus species was well-examined, and its antifungal susceptibility was specifically measured by the microbroth dilution method. The risk factors of patients with IA were documented and analyzed intensively. In addition, gene sequencing was employed to determine gene mutations of cytochrome P450 14-α sterol demethylase-Aspergillus (cyp51A) associated with azole resistance among Aspergillus fumigatus.ResultsThe Aspergillus species distribution was dominated by A. fumigatus (56.41%), Aspergillus flavus (20.51%), and Aspergillus niger (15.38%) locally. In particular, all Aspergillus species showed very low minimum inhibitory concentrations (MICs, ≤ 0.5 μg/ml) for azoles and echinocandins, slightly high MICs (1.66–2.91 μg/ml) for amphotericin B, and exceptionally high MICs (>64 μg/ml) for flucytosine. Azole-resistant rate of Aspergillus species in this local region reached up to 5.79%. Correlation analyses of multiple antifungals indicate a significant MIC relevance between isavuconazole and voriconazole (Pearson correlation coefficient was 0.81, P < 0.0001). The clinical risk factors for patients with IA were found primarily to be pulmonary diseases (P = 0.007) and patients' age (P < 0.001). Notably, three mutant loci (TR46/Y121F/T289A) of the cyp51A gene were identified in azole-resistant A. fumigatus.ConclusionsThe Aspergillus species emerged increasingly, of which A. fumigatus and A. flavus remained the main pathogens for invasive Aspergillus infections in the local region. The vast majority of Aspergillus species exhibited good susceptibility to all the antifungals, except flucytosine. The local occurrence of azole-resistant Aspergillus species grew gradually and needed monitoring in time. Pulmonary diseases and age were likely considered as highly associated risk factors for IA. To our knowledge, the clinically isolated azole-resistant A. fumigatus with TR46/Y121F/T289A mutations identified here were rarely reported in the area of China.
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Rogers TR, Verweij PE, Castanheira M, Dannaoui E, White PL, Arendrup MC. OUP accepted manuscript. J Antimicrob Chemother 2022; 77:2053-2073. [PMID: 35703391 PMCID: PMC9333407 DOI: 10.1093/jac/dkac161] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The increasing incidence and changing epidemiology of invasive fungal infections continue to present many challenges to their effective management. The repertoire of antifungal drugs available for treatment is still limited although there are new antifungals on the horizon. Successful treatment of invasive mycoses is dependent on a mix of pathogen-, host- and antifungal drug-related factors. Laboratories need to be adept at detection of fungal pathogens in clinical samples in order to effectively guide treatment by identifying isolates with acquired drug resistance. While there are international guidelines on how to conduct in vitro antifungal susceptibility testing, these are not performed as widely as for bacterial pathogens. Furthermore, fungi generally are recovered in cultures more slowly than bacteria, and often cannot be cultured in the laboratory. Therefore, non-culture-based methods, including molecular tests, to detect fungi in clinical specimens are increasingly important in patient management and are becoming more reliable as technology improves. Molecular methods can also be used for detection of target gene mutations or other mechanisms that predict antifungal drug resistance. This review addresses acquired antifungal drug resistance in the principal human fungal pathogens and describes known resistance mechanisms and what in-house and commercial tools are available for their detection. It is emphasized that this approach should be complementary to culture-based susceptibility testing, given the range of mutations, resistance mechanisms and target genes that may be present in clinical isolates, but may not be included in current molecular assays.
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Affiliation(s)
| | | | | | | | | | - Maiken Cavling Arendrup
- Unit of Mycology, Statens Serum Institut, Copenhagen, Denmark
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
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Arastehfar A, Carvalho A, Houbraken J, Lombardi L, Garcia-Rubio R, Jenks J, Rivero-Menendez O, Aljohani R, Jacobsen I, Berman J, Osherov N, Hedayati M, Ilkit M, Armstrong-James D, Gabaldón T, Meletiadis J, Kostrzewa M, Pan W, Lass-Flörl C, Perlin D, Hoenigl M. Aspergillus fumigatus and aspergillosis: From basics to clinics. Stud Mycol 2021; 100:100115. [PMID: 34035866 PMCID: PMC8131930 DOI: 10.1016/j.simyco.2021.100115] [Citation(s) in RCA: 114] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The airborne fungus Aspergillus fumigatus poses a serious health threat to humans by causing numerous invasive infections and a notable mortality in humans, especially in immunocompromised patients. Mould-active azoles are the frontline therapeutics employed to treat aspergillosis. The global emergence of azole-resistant A. fumigatus isolates in clinic and environment, however, notoriously limits the therapeutic options of mould-active antifungals and potentially can be attributed to a mortality rate reaching up to 100 %. Although specific mutations in CYP 51A are the main cause of azole resistance, there is a new wave of azole-resistant isolates with wild-type CYP 51A genotype challenging the efficacy of the current diagnostic tools. Therefore, applications of whole-genome sequencing are increasingly gaining popularity to overcome such challenges. Prominent echinocandin tolerance, as well as liver and kidney toxicity posed by amphotericin B, necessitate a continuous quest for novel antifungal drugs to combat emerging azole-resistant A. fumigatus isolates. Animal models and the tools used for genetic engineering require further refinement to facilitate a better understanding about the resistance mechanisms, virulence, and immune reactions orchestrated against A. fumigatus. This review paper comprehensively discusses the current clinical challenges caused by A. fumigatus and provides insights on how to address them.
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Affiliation(s)
- A. Arastehfar
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, 07110, USA
| | - A. Carvalho
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B's - PT Government Associate Laboratory, Guimarães/Braga, Portugal
| | - J. Houbraken
- Westerdijk Fungal Biodiversity Institute, Utrecht, the Netherlands
| | - L. Lombardi
- UCD Conway Institute and School of Medicine, University College Dublin, Dublin 4, Ireland
| | - R. Garcia-Rubio
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, 07110, USA
| | - J.D. Jenks
- Department of Medicine, University of California San Diego, San Diego, CA, 92103, USA
- Clinical and Translational Fungal-Working Group, University of California San Diego, La Jolla, CA, 92093, USA
| | - O. Rivero-Menendez
- Medical Mycology Reference Laboratory, National Center for Microbiology, Instituto de Salud Carlos III, Madrid, 28222, Spain
| | - R. Aljohani
- Department of Infectious Diseases, Imperial College London, London, UK
| | - I.D. Jacobsen
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology—Hans Knöll Institute, Jena, Germany
- Institute for Microbiology, Friedrich Schiller University, Jena, Germany
| | - J. Berman
- Research Group Microbial Immunology, Leibniz Institute for Natural Product Research and Infection Biology—Hans Knöll Institute, Jena, Germany
| | - N. Osherov
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine Ramat-Aviv, Tel-Aviv, 69978, Israel
| | - M.T. Hedayati
- Invasive Fungi Research Center/Department of Medical Mycology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - M. Ilkit
- Division of Mycology, Department of Microbiology, Faculty of Medicine, Çukurova University, 01330, Adana, Turkey
| | | | - T. Gabaldón
- Life Sciences Programme, Supercomputing Center (BSC-CNS), Jordi Girona, Barcelona, 08034, Spain
- Mechanisms of Disease Programme, Institute for Research in Biomedicine (IRB), Barcelona, Spain
- ICREA, Pg. Lluís Companys 23, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, 08010, Barcelona, Spain
| | - J. Meletiadis
- Clinical Microbiology Laboratory, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | | | - W. Pan
- Medical Mycology, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, 200003, China
| | - C. Lass-Flörl
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - D.S. Perlin
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, 07110, USA
| | - M. Hoenigl
- Department of Medicine, University of California San Diego, San Diego, CA, 92103, USA
- Section of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Medical University of Graz, 8036, Graz, Austria
- Division of Infectious Diseases and Global Public Health, Department of Medicine, University of California San Diego, San Diego, CA 92093, USA
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10
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Parent-Michaud M, Dufresne PJ, Fournier E, Folch B, Martineau C, Moreira S, Doucet N, De Repentigny L, Dufresne SF. Prevalence and mechanisms of azole resistance in clinical isolates of Aspergillus section Fumigati species in a Canadian tertiary care centre, 2000 to 2013. J Antimicrob Chemother 2021; 75:849-858. [PMID: 31891387 DOI: 10.1093/jac/dkz534] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 11/14/2019] [Accepted: 12/01/2019] [Indexed: 01/02/2023] Open
Abstract
OBJECTIVES Azole resistance among Aspergillus fumigatus isolates is a growing concern worldwide. Induction of mutations during azole therapy, environment-acquired mutations caused by azole fungicides and intrinsic resistance of cryptic Fumigati species all contribute to the burden of resistance. However, there is a lack of data in Canada on this emerging threat. METHODS To gain insights into the magnitude and mechanisms of resistance, a 14 year collection of Aspergillus section Fumigati comprising 999 isolates from 807 patients at a Montreal hospital was screened for azole resistance, and resistance mechanisms were investigated with the combined use of genome sequencing, 3D modelling and phenotypic efflux pump assays. RESULTS Overall azole resistance was low (4/807 patients; 0.5%). A single azole-resistant A. fumigatus sensu stricto strain, isolated from a patient with pulmonary aspergillosis, displayed efflux-pump-mediated resistance. Three patients were colonized or infected with azole-resistant cryptic Fumigati species (one Aspergillus thermomutatus, one Aspergillus lentulus and one Aspergillus turcosus). Evidence is presented that azole resistance is efflux-pump-mediated in the A. turcosus isolate, but not in the A. lentulus and A. thermomutatus isolates. CONCLUSIONS Azole resistance is rare in our geographic area and currently driven by cryptic Fumigati species. Continued surveillance of emergence of resistance is warranted.
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Affiliation(s)
- Maxime Parent-Michaud
- Department of Microbiology, Infectious Diseases and Immunology, University of Montreal, Montreal, Quebec, Canada
| | - Philippe J Dufresne
- Laboratoire de santé publique du Québec, Institut national de santé publique du Québec, Sainte-Anne-de-Bellevue, Quebec, Canada
| | - Eric Fournier
- Laboratoire de santé publique du Québec, Institut national de santé publique du Québec, Sainte-Anne-de-Bellevue, Quebec, Canada
| | - Benjamin Folch
- INRS-Institut Armand Frappier, University of Quebec, Laval, Quebec, Canada
| | - Christine Martineau
- Laboratoire de santé publique du Québec, Institut national de santé publique du Québec, Sainte-Anne-de-Bellevue, Quebec, Canada
| | - Sandrine Moreira
- Laboratoire de santé publique du Québec, Institut national de santé publique du Québec, Sainte-Anne-de-Bellevue, Quebec, Canada
| | - Nicolas Doucet
- INRS-Institut Armand Frappier, University of Quebec, Laval, Quebec, Canada
| | - Louis De Repentigny
- Department of Microbiology, Infectious Diseases and Immunology, University of Montreal, Montreal, Quebec, Canada
| | - Simon F Dufresne
- Department of Microbiology, Infectious Diseases and Immunology, University of Montreal, Montreal, Quebec, Canada.,Division of Infectious Diseases and Clinical Microbiology, Department of Medicine, Maisonneuve-Rosemont Hospital, Montreal, Quebec, Canada
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11
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Fan Y, Wang Y, Korfanty GA, Archer M, Xu J. Genome-Wide Association Analysis for Triazole Resistance in Aspergillus fumigatus. Pathogens 2021; 10:701. [PMID: 34199862 PMCID: PMC8227032 DOI: 10.3390/pathogens10060701] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 05/24/2021] [Accepted: 06/02/2021] [Indexed: 12/14/2022] Open
Abstract
Aspergillus fumigatus is a ubiquitous fungus and the main agent of aspergillosis, a common fungal infection in the immunocompromised population. Triazoles such as itraconazole and voriconazole are the common first-line drugs for treating aspergillosis. However, triazole resistance in A. fumigatus has been reported in an increasing number of countries. While most studies of triazole resistance have focused on mutations in the triazole target gene cyp51A, >70% of triazole-resistant strains in certain populations showed no mutations in cyp51A. To identify potential non-cyp51A mutations associated with triazole resistance in A. fumigatus, we analyzed the whole genome sequences and triazole susceptibilities of 195 strains from 12 countries. These strains belonged to three distinct clades. Our genome-wide association study (GWAS) identified a total of six missense mutations significantly associated with itraconazole resistance and 18 missense mutations with voriconazole resistance. In addition, to investigate itraconazole and pan-azole resistance, Fisher's exact tests revealed 26 additional missense variants tightly linked to the top 20 SNPs obtained by GWAS, of which two were consistently associated with triazole resistance. The large number of novel mutations related to triazole resistance should help further investigations into their molecular mechanisms, their clinical importance, and the development of a comprehensive molecular diagnosis toolbox for triazole resistance in A. fumigatus.
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Affiliation(s)
| | | | | | | | - Jianping Xu
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada; (Y.F.); (Y.W.); (G.A.K.); (M.A.)
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12
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Effects of Itraconazole and Micafungin on Aspergillus fumigatus Biofilms. Mycopathologia 2021; 186:387-397. [PMID: 33956291 DOI: 10.1007/s11046-021-00534-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 02/10/2021] [Indexed: 10/20/2022]
Abstract
Aspergillus fumigatus (A. fumigatus) is the most common airborne opportunistic fungal pathogen. Biofilm formation is one of the main pathogenic mechanisms of A. fumigatus. During the past decades, A. fumigatus azole resistance has become prevalent due to the medical and agricultural use of antifungal drugs and fungicides. Until now, the role of fungal biofilms in azole resistance of A. fumigatus remains unclear. In the present study, we compared biofilm drug susceptibility and biofilm formation under itraconazole of azole-resistant strains, sensitive strains, and standard strains, separately. The biofilm viability and matrix thickness at the early and the late stage were measured by XTT assay and Calcofluor white. Our results showed that the sessile minimum inhibitory concentration of itraconazole, which describing the inhibition of drugs on fungi sessile with biofilm, was much higher than the traditional minimal inhibitory concentration of itraconazole. Additionally, low concentrations of itraconazole inhibited biofilm formation of A. fumigatus strains. Notably, biofilm formation by azole-resistant strains could not be inhibited by high concentrations of itraconazole but could be effectively restrained by low concentrations of micafungin, revealing the efficacy of a cell-wall inhibitor to disrupt A. fumigatus biofilm formation. However, late-stage biofilms of both azole-resistant strains and standard strains were hard to disrupt using itraconazole. We found that itraconazole was effective to prevent A. fumigatus biofilm formation at the early stage. For the treatment of A. fumigatus biofilm, our findings suggest that an early-stage preventive strategy is preferred and micafungin is effective to control the azole-resistant strain infection.
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13
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Potency of olorofim (F901318) compared to contemporary antifungal agents against clinical Aspergillus fumigatus isolates, and review of azole resistance phenotype and genotype epidemiology in China. Antimicrob Agents Chemother 2021; 65:AAC.02546-20. [PMID: 33685896 PMCID: PMC8092882 DOI: 10.1128/aac.02546-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Triazole resistance in A. fumigatus is an increasing worldwide problem that causes major challenges in the management of aspergillosis. New antifungal drugs are needed with novel targets, that are effective in triazole-resistant infection. In this study, we retrospectively evaluated potency of the novel drug olorofim compared to contemporary antifungal agents against 111 clinical A. fumigatus isolates collected from Huashan Hospital, Shanghai, China, using EUCAST methodology, and reviewed the literature on triazole resistant A. fumigatus published between 1966 and 2020 in China. Olorofim was active in vitro against all tested A. fumigatus isolates with MIC90 of 0.031mg/L (range 0.008-0.062 mg/L). For 4 triazole-resistant A. fumigatus (TRAF) isolates, the olorofim MIC ranged between 0.016-0.062mg/L. The reported rates of TRAF in China is 2.5% - 5.56% for clinical isolates, and 0-1.4% for environmental isolates.TR34/L98H/S297T/F495I is the predominant resistance mechanism, followed by TR34/L98H. Non TR-mediated TRAF isolates, mostly harboring a cyp51A single point mutation, showed greater genetic diversity than TR-mediated resistant isolates. Resistance due toTR34/L98H and TR34/L98H/S297T/F495I mutations among TRAF isolates might have evolved from separate local isolates in China. Continuous isolation of TRAF in China underscores the need for systematic resistance surveillance as well as the need for novel drug targets such as olorofim.
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14
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The C 2H 2 Transcription Factor SltA Contributes to Azole Resistance by Coregulating the Expression of the Drug Target Erg11A and the Drug Efflux Pump Mdr1 in Aspergillus fumigatus. Antimicrob Agents Chemother 2021; 65:AAC.01839-20. [PMID: 33431412 DOI: 10.1128/aac.01839-20] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 12/29/2020] [Indexed: 02/07/2023] Open
Abstract
The emergence of azole-resistant fungal pathogens has posed a great threat to public health worldwide. Although the molecular mechanism of azole resistance has been extensively investigated, the potential regulators of azole resistance remain largely unexplored. In this study, we identified a new function of the fungal specific C2H2 zinc finger transcription factor SltA (involved in the salt tolerance pathway) in the regulation of azole resistance of the human fungal pathogen Aspergillus fumigatus A lack of SltA results in an itraconazole hypersusceptibility phenotype. Transcriptional profiling combined with LacZ reporter analysis and electrophoretic mobility shift assays (EMSA) demonstrated that SltA is involved in its own transcriptional regulation and also regulates the expression of genes related to ergosterol biosynthesis (erg11A, erg13A, and erg24A) and drug efflux pumps (mdr1, mfsC, and abcE) by directly binding to the conserved 5'-AGGCA-3' motif in their promoter regions, and this binding is dependent on the conserved cysteine and histidine within the C2H2 DNA binding domain of SltA. Moreover, overexpression of erg11A or mdr1 rescues sltA deletion defects under itraconazole conditions, suggesting that erg11A and mdr1 are related to sltA-mediated itraconazole resistance. Most importantly, deletion of SltA in laboratory-derived and clinical azole-resistant isolates significantly attenuates drug resistance. Collectively, we have identified a new function of the transcription factor SltA in regulating azole resistance by coordinately mediating the key azole target Erg11A and the drug efflux pump Mdr1, and targeting SltA may provide a potential strategy for intervention of clinical azole-resistant isolates to improve the efficiency of currently approved antifungal drugs.
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15
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Xu Y, Chen M, Zhu J, Gerrits van den Ende B, Chen AJ, Al-Hatmi AMS, Li L, Zhang Q, Xu J, Liao W, Chen Y. Aspergillus Species in Lower Respiratory Tract of Hospitalized Patients from Shanghai, China: Species Diversity and Emerging Azole Resistance. Infect Drug Resist 2020; 13:4663-4672. [PMID: 33402838 PMCID: PMC7778383 DOI: 10.2147/idr.s281288] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 11/28/2020] [Indexed: 01/19/2023] Open
Abstract
Purpose To investigate species diversity and prevalence of antifungal resistance among clinical isolates of Aspergillus spp. in Shanghai, China. Patients and Methods In this study, the Aspergillus spp. isolates were analyzed by multilocus sequence typing (MLST) targeting the internal transcribed spacer (ITS) regions, and partial β-tubulin (BenA) and calmodulin (CaM) genes. The susceptibilities of these isolates to nine antifungal agents were determined according to the protocol in document M38-A3 established by the Clinical and Laboratory Standards Institute (CLSI). Results The most common Aspergillus spp. was A. fumigatus (58.2%), followed by the A. flavus complex (23.5%), and A. niger complex (15.3%). Isolates belonging to A. tamarii and A. effusus of the A. flavus complex and A. tubingensis and A. awamori of the A. niger complex were identified. Moreover, several mutations were found in the azole target cyp51A gene (TR46/Y121F/T289A and F46Y, G89G, M172V, N248T and D255E) in azole-resistant isolates of A. fumigatus. Conclusion The results of our study revealed a diversity of species in the lower respiratory tract of inpatients in Shanghai and approximately 9% of our isolates were resistant to at least one of the triazole antifungals. Formulation of local treatment strategies to combat emerging azole resistance and species diversity in clinically relevant Aspergillus spp. is needed.
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Affiliation(s)
- Yuan Xu
- Department of Dermatology, The Third People's Hospital of Hangzhou, Hangzhou, People's Republic of China.,Department of Dermatology, Shanghai Key Laboratory of Molecular Medical Mycology, ChangZheng Hospital, Second Military Medical University, Shanghai, People's Republic of China
| | - Min Chen
- Department of Dermatology, Shanghai Key Laboratory of Molecular Medical Mycology, ChangZheng Hospital, Second Military Medical University, Shanghai, People's Republic of China
| | - Junhao Zhu
- Department of Dermatology, Huashan Hospital, Fudan University, Shanghai, People's Republic of China
| | - Bert Gerrits van den Ende
- Department of Food and Indoor Mycology, Westerdijk Fungal Biodiversity Institute, Utrecht, the Netherlands
| | - Amanda Juan Chen
- Department of Medical Mycology, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China
| | - Abdullah M S Al-Hatmi
- Centre of Expertise in Mycology, Radboud University Medical Centre, Canisius Wilhelmina Hospital, Nijmegen, the Netherlands.,Ministry of Health, Directorate General of Health Services, Ibri, Oman
| | - Li Li
- Department of Dermatology, Huashan Hospital, Fudan University, Shanghai, People's Republic of China
| | - Qiangqiang Zhang
- Department of Dermatology, Huashan Hospital, Fudan University, Shanghai, People's Republic of China
| | - Jianping Xu
- Department of Biology, McMaster University, Hamilton, Canada
| | - Wanqing Liao
- Department of Dermatology, Shanghai Key Laboratory of Molecular Medical Mycology, ChangZheng Hospital, Second Military Medical University, Shanghai, People's Republic of China
| | - Yuchong Chen
- Department of Dermatosurgery, Shanghai Skin Diseases Hospital, School of Medicine, Tongji University, Shanghai, People's Republic of China
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16
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Five-Year Survey (2014 to 2018) of Azole Resistance in Environmental Aspergillus fumigatus Isolates from China. Antimicrob Agents Chemother 2020; 64:AAC.00904-20. [PMID: 32718960 DOI: 10.1128/aac.00904-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 07/19/2020] [Indexed: 01/05/2023] Open
Abstract
A total of 191 soil samples from Hangzhou, China, were submitted to detect non-wild-type (non-WT) Aspergillus fumigatus and its associated mechanisms. There were 2 (4.7%), 13 (12.4%), and 31 (23.1%) isolates identified as non-WT in 2014, 2016, and 2018, respectively. The resistant mutations of TR34/L98H, TR46/Y121F/T289A, and TR34/L98H/S297T/F495I were found in 3, 5, and 5 non-WT isolates. The G448S mutation, previously only found in clinical settings, was detected in A. fumigatus from soil samples.
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17
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Bustamante B, Illescas LR, Posadas A, Campos PE. Azole resistance among clinical isolates of Aspergillus fumigatus in Lima-Peru. Med Mycol 2020; 58:54-60. [PMID: 31329931 DOI: 10.1093/mmy/myz032] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 03/05/2019] [Accepted: 03/13/2019] [Indexed: 11/13/2022] Open
Abstract
Azole resistance among Aspergillus fumigatus isolates, which is mainly related to mutations in the cyp51A gene, is a concern because it is rising, worldwide disseminated, and associated with treatment failure and death. Data on azole resistance of aspergillus from Latin American countries is very scarce and do not exist for Peru. Two hundred and seven Aspergillus clinical isolates collected prospectively underwent mycology and molecular testing for specie identification, and 143 isolates were confirmed as A. fumigatus sensu stricto (AFSS). All AFSS were tested for in vitro azole susceptibility, and resistant isolates underwent PCR amplification and sequencing of the whole cyp51A gene and its promoter. The in vitro susceptibility showed a minimal inhibitory concentration (MIC) range, MIC50 and MIC90 of 0.125 to >16, 0.25, and 0.5 μg/ml for itraconazole; 0.25 to 2, 0.5, and 0.5 μg/ml for voriconazole; and 0.003 to 1, 0.06, and 0.125 μg/ml for posaconazole. Three isolates (2%) showed resistance to itraconazole and exhibited different mutations of the cyp51A gene. One isolate harbored the mutation M220K, while a second one exhibited the G54 mutation plus a modification in the cyp51A gene promoter. The third isolate, from an azole naive patient, presented an integration of a 34-bp tandem repeat (TR34) in the promoter region of the gene and a substitution of leucine 98 by histidine (L98H). The three source patients had a diagnosis or suspicion of chronic pulmonary aspergillosis.
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Affiliation(s)
- Beatriz Bustamante
- Nacional Cayetano Heredia, Lima, Perú, and Instituto de Medicina Tropical Alexander von Humboldt-Universidad Peruana Cayetano Heredia, Lima, Peru
| | | | - Andrés Posadas
- Unidad de Epidemiología Molecular-Instituto de Medicina Tropical Alexander von Humboldt-Universidad Peruana Cayetano Heredia, Lima, Peru
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18
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Moin S, Farooqi J, Jabeen K, Laiq S, Zafar A. Screening for triazole resistance in clinically significant Aspergillus species; report from Pakistan. Antimicrob Resist Infect Control 2020; 9:62. [PMID: 32393344 PMCID: PMC7216335 DOI: 10.1186/s13756-020-00731-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 05/06/2020] [Indexed: 12/27/2022] Open
Abstract
Background Burden of aspergillosis is reported to be significant from developing countries including those in South Asia. The estimated burden in Pakistan is also high on the background of tuberculosis and chronic lung diseases. There is concern for management of aspergillosis with the emergence of azole resistant Aspergillus species in neighbouring countries in Central and South Asia. Hence the aim of this study was to screen significant Aspergillus species isolates at the Microbiology Section of Aga Khan Clinical Laboratories, Pakistan, for triazole resistance. Methods A descriptive cross-sectional study, conducted at the Aga Khan University Laboratories, Karachi, from September 2016–May 2019. One hundred and fourteen, clinically significant Aspergillus isolates [A. fumigatus (38; 33.3%), A. flavus (64; 56.1%), A. niger (9; 7.9%) A. terreus (3; 2.6%)] were included. The clinical spectrum ranged from invasive aspergillosis (IA) (n = 25; 21.9%), chronic pulmonary aspergillosis (CPA) (n = 58; 50.9%), allergic bronchopulmonary aspergillosis (ABPA) (n = 4; 3.5%), severe asthma with fungal sensitization (SAFS) (n = 4; 3.5%), saprophytic tracheobronchial aspergillosis (n = 23; 20.2%). Screening for triazole resistance was performed by antifungal agar screening method. The minimum inhibitory concentration (MIC) of 41 representative isolates were tested and interpreted according to the Clinical and Laboratory Standards Institute broth microdilution method. Results All the isolates were triazole-susceptible on agar screening. MICs of three azole antifungals for 41 tested isolates were found to be ≤1 ml/L; all isolates tested were categorized as triazole-susceptible, including 4 isolates from patients previously on triazole therapy for more than 2 weeks. The minimum inhibitory concentration required to inhibit the growth of 90% organisms (MIC90) of itraconazole, voriconazole and posaconazole of the representative Aspergillus isolates was 1 mg/L, 1 mg/L and 0.5 mg/L, respectively. Conclusion Triazole resistance could not be detected amongst clinical Aspergillus isolates from the South of Pakistan. However, environmental strains remain to be tested for a holistic assessment of the situation. This study will set precedence for future periodic antifungal resistance surveillance in our region on Aspergillus isolates.
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Affiliation(s)
- Safia Moin
- Department of Pathology and Laboratory Medicine, Aga Khan University, Karachi, Pakistan
| | - Joveria Farooqi
- Department of Pathology and Laboratory Medicine, Aga Khan University, Karachi, Pakistan.
| | - Kauser Jabeen
- Department of Pathology and Laboratory Medicine, Aga Khan University, Karachi, Pakistan
| | - Sidra Laiq
- Department of Pathology and Laboratory Medicine, Aga Khan University, Karachi, Pakistan
| | - Afia Zafar
- Department of Pathology and Laboratory Medicine, Aga Khan University, Karachi, Pakistan
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19
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Comparison of Two Typing Methods for Characterization of Azole Resistance in Aspergillus fumigatus from Potting Soil Samples in a Chinese Hospital. Antimicrob Agents Chemother 2020; 64:AAC.01578-19. [PMID: 31740554 DOI: 10.1128/aac.01578-19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 10/27/2019] [Indexed: 12/29/2022] Open
Abstract
To understand the characterizations of azole resistance in Aspergillus fumigatus from potting soil samples in the hospital, a total of 58 samples were collected. Among 106 A. fumigatus samples obtained, 5 isolates from 4 soil samples located in the gerontology department were identified as azole-resistant A. fumigatus (ARAF). Four ARAF isolates harbored the TR34/L98H allele, and the other one had no mutation in the cyp51A gene. Among 174 A. fumigatus samples selected for genotyping, TRESPERG typing obtained a close discriminatory power (Simpson's index of diversity [DI], 0.9941; 95% confidence interval [CI], 0.9913 to 0.9968) compared with the short tandem repeat (STR) typing (DI, 0.9997; 95% CI, 0.9976 to 1.0000). Genotyping showed that the TR34/L98H isolates in the hospital had a close genetic relationship with ARAF isolates from China and many other countries. In conclusion, this study indicated the presence of ARAF in potting soil samples from the hospital, which might pose a risk of causing ARAF infection in patients.
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20
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Chen P, Liu M, Zeng Q, Zhang Z, Liu W, Sang H, Lu L. Uncovering New Mutations Conferring Azole Resistance in the Aspergillus fumigatus cyp51A Gene. Front Microbiol 2020; 10:3127. [PMID: 32038564 PMCID: PMC6986205 DOI: 10.3389/fmicb.2019.03127] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 12/24/2019] [Indexed: 11/28/2022] Open
Abstract
The opportunistic pathogen Aspergillus fumigatus has developed worldwide resistance to azoles largely through mutations in cytochromeP450 enzyme Cyp51. In this study, we indicated that in vitro azole situation results in emergence of azole-resistant mutations. There are previously identified azole-resistant cyp51A mutations (M220K, M220I, M220R, G54E and G54W mutations) and we successfully identified in this study two new mutations (N248K/V436A, Y433N substitution) conferring azole resistance among 18 independent stable azole-resistant isolates. The Galleria mellonella model of A. fumigatus infection experiment verified that Cyp51A mutations N248K/V436A and Y433N reduce efficacy of azole therapy. In addition, a predicted Cyp51A 3D structural model suggested that Y433N mutation causes the reduced affinities between drug target Cyp51A and azole antifungals. This study suggests that drug selection pressure make it possible to isolate unidentified cyp51A mutations conferring azole resistance in A. fumigatus.
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Affiliation(s)
- Peiying Chen
- Department of Dermatology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, China
| | - Musang Liu
- Department of Medical Mycology, Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, China.,Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, China
| | - Qiuqiong Zeng
- Department of Dermatology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, China
| | - Zheng Zhang
- Department of Dermatology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, China
| | - Weida Liu
- Department of Medical Mycology, Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, China.,Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, China
| | - Hong Sang
- Department of Dermatology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, China
| | - Ling Lu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
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21
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van der Torre MH, Novak-Frazer L, Rautemaa-Richardson R. Detecting Azole-Antifungal Resistance in Aspergillus fumigatus by Pyrosequencing. J Fungi (Basel) 2020; 6:jof6010012. [PMID: 31936898 PMCID: PMC7151159 DOI: 10.3390/jof6010012] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 01/08/2020] [Accepted: 01/08/2020] [Indexed: 12/12/2022] Open
Abstract
Guidelines on the diagnosis and management of Aspergillus disease recommend a multi-test approach including CT scans, culture, fungal biomarker tests, microscopy and fungal PCR. The first-line treatment of confirmed invasive aspergillosis (IA) consists of drugs in the azole family; however, the emergence of azole-resistant isolates has negatively impacted the management of IA. Failure to detect azole-resistance dramatically increases the mortality rates of azole-treated patients. Despite drug susceptibility tests not being routinely performed currently, we suggest including resistance testing whilst diagnosing Aspergillus disease. Multiple tools, including DNA sequencing, are available to screen for drug-resistant Aspergillus in clinical samples. This is particularly beneficial as a large proportion of IA samples are culture negative, consequently impeding susceptibility testing through conventional methods. Pyrosequencing is a promising in-house DNA sequencing method that can rapidly screen for genetic hotspots associated with antifungal resistance. Pyrosequencing outperforms other susceptibility testing methods due to its fast turnaround time, accurate detection of polymorphisms within critical genes, including simultaneous detection of wild type and mutated sequences, and—most importantly—it is not limited to specific genes nor fungal species. Here we review current diagnostic methods and highlight the potential of pyrosequencing to aid in a diagnosis complete with a resistance profile to improve clinical outcomes.
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Affiliation(s)
- Mireille H. van der Torre
- Mycology Reference Centre, Excellence Centre of Medical Mycology (ECMM), Manchester University NHS Foundation Trust-Wythenshawe Hospital, Manchester M23 9LT, UK; (M.H.v.d.T.); (L.N.-F.)
| | - Lilyann Novak-Frazer
- Mycology Reference Centre, Excellence Centre of Medical Mycology (ECMM), Manchester University NHS Foundation Trust-Wythenshawe Hospital, Manchester M23 9LT, UK; (M.H.v.d.T.); (L.N.-F.)
- Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, NIHR Manchester Biomedical Research Centre (BRC) at the Manchester Academic Health Science Centre, The University of Manchester, Manchester M23 9LT, UK
| | - Riina Rautemaa-Richardson
- Mycology Reference Centre, Excellence Centre of Medical Mycology (ECMM), Manchester University NHS Foundation Trust-Wythenshawe Hospital, Manchester M23 9LT, UK; (M.H.v.d.T.); (L.N.-F.)
- Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, NIHR Manchester Biomedical Research Centre (BRC) at the Manchester Academic Health Science Centre, The University of Manchester, Manchester M23 9LT, UK
- Department of Infectious Diseases, Manchester University NHS Foundation Trust-Wythenshawe Hospital, Manchester M23 9LT, UK
- Correspondence: ; Tel.: +44-161-291-5941
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22
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Azole-resistant Aspergillus fumigatus: A global phenomenon originating in the environment? Med Mal Infect 2019; 50:389-395. [PMID: 31472992 DOI: 10.1016/j.medmal.2019.07.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 10/09/2018] [Accepted: 07/24/2019] [Indexed: 11/22/2022]
Abstract
Aspergillus fumigatus is the predominant etiological agent of invasive aspergillosis (IA), a difficult-to-manage fungal disease associated with a high case fatality rate. Azole antifungals, particularly voriconazole, have significantly improved the survival rate of patients with IA. However, the clinical advances made possible through the use of medical azoles could be threatened by the emergence of azole-resistant strains which has been reported in an ever-increasing number of countries over the last 10 years. The major resistance mechanism, that combines point mutation(s) in the coding sequence of cyp51A gene and an insertion of a tandem repeat in the promoter region of this gene which leads to its overexpression (TR34/L98H and TR46/Y121F/T289A), is presumed to be of environmental origin. However, the emergence of clinical and environmental azole-resistant strains without the cyp51A gene mutation suggests that other mechanisms could also be responsible for azole resistance (for example, overexpression of efflux pumps). The development of resistance may be linked to either long-term use of azole antifungals in patients with chronic aspergillosis (patient-acquired route) or selection pressure of the fungicides in the environment (environmental route). The fungicide-driven route could be responsible for resistance in azole-naive patients with IA. This literature review aims to summarize recent findings, focusing on the current situation of azole-resistance in A. fumigatus, and provides better understanding of the importance of the environmental route in resistance acquisition.
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23
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A Novel Broad Allele-Specific TaqMan Real-Time PCR Method To Detect Triazole-Resistant Strains of Aspergillus fumigatus, Even with a Very Low Percentage of Triazole-Resistant Cells Mixed with Triazole-Susceptible Cells. J Clin Microbiol 2019; 57:JCM.00604-19. [PMID: 31315952 DOI: 10.1128/jcm.00604-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 07/08/2019] [Indexed: 11/20/2022] Open
Abstract
Invasive aspergillosis caused by triazole-resistant strains of Aspergillus fumigatus is a growing public health concern, as is the occurrence of mixed infections with triazole-resistant and -susceptible A. fumigatus strains. Therefore, it is crucial to develop robust methods to identify triazole-resistant strains of A. fumigatus, even in mixtures of triazole-resistant and -susceptible strains of A. fumigatus In this work, we developed a robust, highly selective, and broad-range allele-specific TaqMan real-time PCR platform consisting of 7 simultaneous assays that detect TR34 (a 34-bp tandem repeat in the promoter region), TR46, G54W (a change of G to W at position 54), G54R, L98H, Y121F, and M220I mutations in the cyp51A gene of A. fumigatus The method is based on the widely used TaqMan real-time PCR technology and combines allele-specific PCR with a blocking reagent (minor groove binder [MGB] oligonucleotide blocker) to suppress amplification of the wild-type cyp51A alleles. We used this method to detect triazole-resistant clinical strains of A. fumigatus with a variety of cyp51A gene mutations, as well as the triazole-resistant strains in mixtures of triazole-resistant and -susceptible strains of A. fumigatus The method had high efficiency and sensitivity (300 fg/well, corresponding to about 100 CFU per reaction mixture volume). It could promptly detect triazole resistance in a panel of 30 clinical strains of A. fumigatus within about 6 h. It could also detect cyp51A-associated resistance alleles, even in mixtures containing only 1% triazole-resistant A. fumigatus strains. These results suggest that this method is robustly able to detect cyp51A-associated resistance alleles even in mixtures of triazole-resistant and -susceptible strains of A. fumigatus and that it should have important clinical applications.
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24
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Korfanty GA, Teng L, Pum N, Xu J. Contemporary Gene Flow is a Major Force Shaping the Aspergillus fumigatus Population in Auckland, New Zealand. Mycopathologia 2019; 184:479-492. [PMID: 31309402 DOI: 10.1007/s11046-019-00361-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 07/08/2019] [Indexed: 12/24/2022]
Abstract
Aspergillus fumigatus is a globally distributed opportunistic fungal pathogen capable of causing highly lethal invasive aspergillosis in immunocompromised individuals. Recent studies have indicated that the global population consists of multiple, divergent genetic clusters that are geographically broadly distributed. However, most of the analyzed samples have come from continental Eurasia and the Americas where the effects of ancient versus recent factors are difficult to distinguish. Here, we investigated environmental A. fumigatus isolates from Auckland, New Zealand, a geographically isolated population, and compared them with those from other parts of the world to determine the relative roles of historical differentiation and recent gene flow in shaping A. fumigatus populations. Our data suggest that the Auckland A. fumigatus population contains both unique indigenous genetic elements as well as genetic elements that are similar to those from other regions such as Europe, Africa, and North America. Though the hypothesis of random recombination was rejected, we found abundant evidence for phylogenetic incompatibility and recombination within the Auckland A. fumigatus population. Additionally, susceptibility testing identified two triazole-resistant strains, one of which contained the globally distributed mutation TR34/L98H in the cyp51A gene. Our results suggest that contemporary gene flow, likely due to anthropogenic factors, is a major force shaping the New Zealand A. fumigatus population.
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Affiliation(s)
- Greg A Korfanty
- Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada
| | - Lisa Teng
- Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada
| | - Nicole Pum
- Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada
| | - Jianping Xu
- Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada.
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25
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Triazole resistance in Aspergillus fumigatus: recent insights and challenges for patient management. Clin Microbiol Infect 2019; 25:799-806. [DOI: 10.1016/j.cmi.2018.11.027] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 11/07/2018] [Accepted: 11/30/2018] [Indexed: 01/18/2023]
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26
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Zhang H, Tan J, Kontoyiannis DP, Zhou Y, Liu W, Zhu P, Shi X, Wan Z, Li R, Liu W. Screening the in vitro susceptibility of posaconazole in clinical isolates of Candida spp. and Aspergillus spp. and analyzing the sequence of ERG11 or CYP51A in non-wild-type isolates from China. Diagn Microbiol Infect Dis 2019; 95:166-170. [PMID: 31174994 DOI: 10.1016/j.diagmicrobio.2019.05.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 04/10/2019] [Accepted: 05/01/2019] [Indexed: 01/12/2023]
Abstract
The present study was to determine the in vitro activity of posaconazole (POS) against 385 Candida and 268 Aspergillus clinical isolates from China. We found that POS was active against 85.5% Candida and 94.4% Aspergillus isolates. Non-wild-type (non-WT) phenotype was found in a subset of Candida albicans (15.4%), Candida tropicalis (11.9%), Aspergillus fumigatus (4.1%), and Aspergillus flavus (17.4%) isolates. Cross-resistance to POS and other triazoles was seen. Gene sequencing showed that 4 C. albicans, 1 C. tropicalis, and 9 A. fumigatus isolates with cross-resistance to POS and other triazoles had mutations in ERG11 or CYP51A. In conclusion, POS has potent in vitro activity against most of Candida and Aspergillus isolates from China. Non-WT phenotype and those with cross-resistance to POS and other triazoles exist, frequently driven by mutations of ERG11 in Candida spp. and CYP51A in Aspergillus spp.
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Affiliation(s)
- Hao Zhang
- Department of Dermatology, Peking University First Hospital, Research Center for Medical Mycology, Beijing Key Laboratory of Molecular Diagnosis on Dermatoses, Peking University, Beijing, China
| | - Jingwen Tan
- Department of Dermatology, Peking University First Hospital, Research Center for Medical Mycology, Beijing Key Laboratory of Molecular Diagnosis on Dermatoses, Peking University, Beijing, China
| | - Dimitrios P Kontoyiannis
- Department of Infectious Disease, Infection Control and Employee Health, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Yabin Zhou
- Department of Dermatology, Peking University First Hospital, Research Center for Medical Mycology, Beijing Key Laboratory of Molecular Diagnosis on Dermatoses, Peking University, Beijing, China
| | - Weixia Liu
- Department of Dermatology, Peking University First Hospital, Research Center for Medical Mycology, Beijing Key Laboratory of Molecular Diagnosis on Dermatoses, Peking University, Beijing, China
| | - Pengfei Zhu
- Department of Dermatology, Peking University First Hospital, Research Center for Medical Mycology, Beijing Key Laboratory of Molecular Diagnosis on Dermatoses, Peking University, Beijing, China; Department of Clinical Laboratory, The first affiliated hospital of Zhengzhou University, Zhengzhou, China
| | - Xiuyan Shi
- Department of Dermatology, Peking University First Hospital, Research Center for Medical Mycology, Beijing Key Laboratory of Molecular Diagnosis on Dermatoses, Peking University, Beijing, China; Department of Dermatology, Liaocheng People's Hospital and Clinical School of Taishan Medical University, Liaocheng, China
| | - Zhe Wan
- Department of Dermatology, Peking University First Hospital, Research Center for Medical Mycology, Beijing Key Laboratory of Molecular Diagnosis on Dermatoses, Peking University, Beijing, China
| | - Ruoyu Li
- Department of Dermatology, Peking University First Hospital, Research Center for Medical Mycology, Beijing Key Laboratory of Molecular Diagnosis on Dermatoses, Peking University, Beijing, China
| | - Wei Liu
- Department of Dermatology, Peking University First Hospital, Research Center for Medical Mycology, Beijing Key Laboratory of Molecular Diagnosis on Dermatoses, Peking University, Beijing, China.
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27
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Zeng Q, Zhang Z, Chen P, Long N, Lu L, Sang H. In vitro and in vivo Efficacy of a Synergistic Combination of Itraconazole and Verapamil Against Aspergillus fumigatus. Front Microbiol 2019; 10:1266. [PMID: 31231346 PMCID: PMC6567931 DOI: 10.3389/fmicb.2019.01266] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 05/22/2019] [Indexed: 12/14/2022] Open
Abstract
The incidence of aspergillosis continues to rise sharply, while the progress made in expanding the antifungal drug arsenal remains extremely slow, indicating an urgent need for new strategies. Previous studies have shown that the calcium signaling pathway, which is evolutionarily conserved in mammals and fungi, is involved in regulating the tolerance of azoles in fungi. In this study, we performed a preliminary screening among various combinations of different clinical calcium channel blockers and different antifungal drugs. We found that the combination of itraconazole and verapamil showed the best synergistic effect against Aspergillus fumigatus. Thereafter, using the checkboard assays we observed synergistic effects of the combination treatment against most of the A. fumigatus strains tested, including itraconazole-sensitive and itraconazole-resistant strains, with a fractional inhibitory concentration index (FICI) < 0.5. Furthermore, we showed that verapamil strongly decreased the cytosolic calcium transients following itraconazole stimulation by an aequorin-mediated method. Moreover, verapamil influenced the efflux of rhodamine 6G, an azole mimic substance. An ergosterol assay revealed that verapamil alone had no effect on ergosterol biosynthesis, but the combination of itraconazole and verapamil treatment decreased the ergosterol level. Further murine assays were performed using a luciferase-probed bioluminescence imaging method. Drug combination therapy reduced lung burden and improved survival rate. In conclusion, verapamil is a promising candidate to enhance the antifungal activity of itraconazole against A. fumigatus. In addition, our study suggests the effectiveness of an emerging approach based on bioluminescence imaging in monitoring the efficacy of drug combination therapy for invasive aspergillosis.
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Affiliation(s)
- Qiuqiong Zeng
- Department of Dermatology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, China
| | - Zheng Zhang
- Department of Dermatology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, China
| | - Peiying Chen
- Department of Dermatology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, China
| | - Nanbiao Long
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Ling Lu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Hong Sang
- Department of Dermatology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, China
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28
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Nash A, Rhodes J. Simulations of CYP51A from Aspergillus fumigatus in a model bilayer provide insights into triazole drug resistance. Med Mycol 2019; 56:361-373. [PMID: 28992260 PMCID: PMC5895076 DOI: 10.1093/mmy/myx056] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 07/14/2017] [Indexed: 11/26/2022] Open
Abstract
Azole antifungal drugs target CYP51A in Aspergillus fumigatus by binding with the active site of the protein, blocking ergosterol biosynthesis. Resistance to azole antifungal drugs is now common, with a leucine to histidine amino acid substitution at position 98 the most frequent, predominantly conferring resistance to itraconazole, although cross-resistance has been reported in conjunction with other mutations. In this study, we create a homology model of CYP51A using a recently published crystal structure of the paralog protein CYP51B. The derived structures, wild type, and L98H mutant are positioned within a lipid membrane bilayer and subjected to molecular dynamics simulations in order improve the accuracy of both models. The structural analysis from our simulations suggests a decrease in active site surface from the formation of hydrogen bonds between the histidine substitution and neighboring polar side chains, potentially preventing the binding of azole drugs. This study yields a biologically relevant structure and set of dynamics of the A. fumigatus Lanosterol 14 alpha-demethylase enzyme and provides further insight into azole antifungal drug resistance.
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Affiliation(s)
- Anthony Nash
- Department of Chemistry, University College London, London, United Kingdom
| | - Johanna Rhodes
- Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
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29
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Triazole Antifungal Susceptibility Patterns among Aspergillus Species in Québec, Canada. J Clin Microbiol 2019; 57:JCM.00404-19. [PMID: 30918044 DOI: 10.1128/jcm.00404-19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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30
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Hagiwara D. Current Status of Azole-resistant Aspergillus fumigatus Isolates in East Asia. Med Mycol J 2019; 59:E71-E76. [PMID: 30504618 DOI: 10.3314/mmj.18.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Aspergillus fumigatus is a saprophytic fungus that is a major causative pathogen for aspergillosis. Only a few classes of antifungals are used for treating this life-threatening fungal infection. Azoles are the first-line drugs and are widely used for the management and prophylaxis of aspergillosis. An emerging issue is the increasing incidence of resistant isolates worldwide. In particular, environmentally derived tandem-repeat-type azole-resistant mutations, such as Cyp51A TR34/L98H, and Cyp51A TR46/Y121F/T289A, have emerged over the last decade. In particular, azole-resistant isolates were prevalent in clinical settings in European countries; many of the reports are from the Netherlands, UK, and Germany. In contrast, reports on azole-resistant A. fumigatus isolates from East Asian countries are still few and have only recently begun to increase. Herein, all literature on East Asian azole-resistant A. fumigatus isolates were reviewed, and a complete list of resistant isolates from China, Japan, Taiwan, and Korea is provided. As of this report, the total numbers of tandem-repeat-type azole-resistant isolates are 26, 3, 32, and 1 in China, Japan, Taiwan, and Korea, respectively.
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Affiliation(s)
- Daisuke Hagiwara
- Faculty of Life and Environmental Sciences, University of Tsukuba.,Medical Mycology Research Center, Chiba University
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31
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Kemoi EK, Nyerere A, Bii CC. Triazole-Resistant Aspergillus fumigatus from Fungicide-Experienced Soils in Naivasha Subcounty and Nairobi County, Kenya. Int J Microbiol 2018; 2018:7147938. [PMID: 30046310 PMCID: PMC6038473 DOI: 10.1155/2018/7147938] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 12/06/2017] [Accepted: 05/03/2018] [Indexed: 11/18/2022] Open
Abstract
The mainstay in prevention and treatment of aspergillosis is the use triazole drugs. In Kenya, the use of agricultural azole is one of the predisposing factors in development of resistance. One hundred fifty-six (156) experienced soils were collected from agricultural farms and cultured on Sabouraud DextroseAagar. The study isolated 48 yielded Aspergillus fumigatus and 2 A. flavus. All the isolates were subjected to antifungal susceptibility testing against three triazoles: posaconazole, voriconazole, and itraconazole. Out of the isolates, 3 had MIC of 32 and 1 had MIC of 16 against itraconazole, and 1 isolate had MIC of 32 against posaconazole. CYP51A gene was sequenced, and TR34/L98H mutation was identified. Triazole resistance existing in Kenya calls for rational use of azole-based fungicides in agriculture over concerns of emerging antifungal resistance in clinical practice.
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Affiliation(s)
- Edson K. Kemoi
- Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
- University of Kabianga, Kericho, Kenya
| | - Andrew Nyerere
- Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
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32
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Elevated MIC Values of Imidazole Drugs against Aspergillus fumigatus Isolates with TR 34/L98H/S297T/F495I Mutation. Antimicrob Agents Chemother 2018; 62:AAC.01549-17. [PMID: 29507067 DOI: 10.1128/aac.01549-17] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Accepted: 02/25/2018] [Indexed: 11/20/2022] Open
Abstract
The use of azole fungicides in agriculture is believed to be one of the main reasons for the emergence of azole resistance in Aspergillus fumigatus Though widely used in agriculture, imidazole fungicides have not been linked to resistance in A. fumigatus This study showed that elevated MIC values of imidazole drugs were observed against A. fumigatus isolates with TR34/L98H/S297T/F495I mutation, but not among isolates with TR34/L98H mutation. Short-tandem-repeat (STR) typing analysis of 580 A. fumigatus isolates from 20 countries suggested that the majority of TR34/L98H/S297T/F495I strains from China were genetically different from the predominant major clade comprising most of the azole-resistant strains and the strains with the same mutation from the Netherlands and Denmark. Alignments of sterol 14α-demethylase sequences suggested that F495I in A. fumigatus was orthologous to F506I in Penicillium digitatum and F489L in Pyrenophora teres, which have been reported to be associated with imidazole resistance. In vitro antifungal susceptibility testing of different recombinants with cyp51A mutations further confirmed the association of the F495I mutation with imidazole resistance. In conclusion, this study suggested that environmental use of imidazole fungicides might confer selection pressure for the emergence of azole resistance in A. fumigatus.
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33
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Epidemiology of fungal infections in China. Front Med 2018; 12:58-75. [DOI: 10.1007/s11684-017-0601-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2017] [Accepted: 10/23/2017] [Indexed: 01/19/2023]
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34
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Deng S, Zhang L, Ji Y, Verweij PE, Tsui KM, Hagen F, Houbraken J, Meis JF, Abliz P, Wang X, Zhao J, Liao W. Triazole phenotypes and genotypic characterization of clinical Aspergillus fumigatus isolates in China. Emerg Microbes Infect 2017; 6:e109. [PMID: 29209054 PMCID: PMC5750463 DOI: 10.1038/emi.2017.97] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Revised: 10/13/2017] [Accepted: 10/16/2017] [Indexed: 01/09/2023]
Abstract
This study investigated the triazole phenotype and genotypic of clinical Aspergillus fumigatus isolates from China. We determined the triazole susceptibility profiles of 159 A. fumigatus isolates collected between 2011 and 2015 from four different areas in China tested against 10 antifungal drugs using the Clinical Laboratory Standard Institute M38-A2 method. For the seven itraconazole-resistant A. fumigatus isolates identified in the study, the cyp51A gene, including its promoter region, was sequenced and the mutation patterns were characterized. The resistant isolates were genotyped by microsatellite typing to determine the genetic relatedness to isolates from China and other countries. The frequency of itraconazole resistance in A. fumigatus isolates in our study was 4.4% (7/159). Six of the seven triazole-resistant isolates were recovered from the east and southeast of China, and one from was recovered from the west of China. No resistant isolates were found in the north. Three triazole-resistant isolates exhibited the TR34/L98H mutation, two carried the TR34/L98H/S297T/F495I mutation and one harbored a G54V mutation in the cyp51A gene. Analysis of the microsatellite markers from seven non-wild-type isolates indicated the presence of five unique genotypes, which clustered into two major genetic groups. The cyp51A gene mutations TR34/L98H and TR34/L98H/S297T were the most frequently found mutations, and the G54V mutation was reported for the first time in China. The geographic origin of the triazole-resistant isolates appeared to concentrate in eastern and south-eastern areas, which suggests that routine antifungal susceptibility testing in these areas should be performed for all clinically relevant A. fumigatus isolates to guide antifungal therapy and for epidemiological purposes.
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Affiliation(s)
- Shuwen Deng
- Department of Medical Microbiology, People's Hospital of Suzhou National New & Hi-Tech Industrial Development Zone, Jiangsu 215219, China
| | - Lili Zhang
- Department of Dermatology, Tongji Hospital of Tongji University, Tongji University School of Medicine, Shanghai 200065, China
| | - Yanfeng Ji
- Department of Dermatology, Tongji Hospital of Tongji University, Tongji University School of Medicine, Shanghai 200065, China
| | - Paul E Verweij
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen 6500HB, The Netherlands
| | - Kin Ming Tsui
- Division of Infectious Diseases, Faculty of Medicine, University of British Columbia, Vancouver V6H3Z6, Canada
| | - Ferry Hagen
- Department of Medical Microbiology & Infectious Diseases, Canisius Wilhelmina Hospital, Nijmegen 6500GS, The Netherlands.,Centre of Expertise in Mycology Radboud University Medical Centre/CWZ, Nijmegen 6500HB, The Netherlands
| | - Jos Houbraken
- Westerdijk Fungal Biodiversity Institute, Utrecht 3584CT, The Netherlands
| | - Jacque F Meis
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen 6500HB, The Netherlands.,Department of Medical Microbiology & Infectious Diseases, Canisius Wilhelmina Hospital, Nijmegen 6500GS, The Netherlands.,Centre of Expertise in Mycology Radboud University Medical Centre/CWZ, Nijmegen 6500HB, The Netherlands
| | - Parida Abliz
- First Hospital of Xinjiang Medical University, Urumqi 830054, China
| | - Xiaodong Wang
- First Hospital of Xinjiang Medical University, Urumqi 830054, China
| | - Jingjun Zhao
- Department of Dermatology, Tongji Hospital of Tongji University, Tongji University School of Medicine, Shanghai 200065, China
| | - Wanqing Liao
- Shanghai Key Laboratory of Molecular Medical Mycology, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China
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35
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Molecular Tools for the Detection and Deduction of Azole Antifungal Drug Resistance Phenotypes in Aspergillus Species. Clin Microbiol Rev 2017; 30:1065-1091. [PMID: 28903985 DOI: 10.1128/cmr.00095-16] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The incidence of azole resistance in Aspergillus species has increased over the past years, most importantly for Aspergillus fumigatus. This is partially attributable to the global spread of only a few resistance alleles through the environment. Secondary resistance is a significant clinical concern, as invasive aspergillosis with drug-susceptible strains is already difficult to treat, and exclusion of azole-based antifungals from prophylaxis or first-line treatment of invasive aspergillosis in high-risk patients would dramatically limit drug choices, thus increasing mortality rates for immunocompromised patients. Management options for invasive aspergillosis caused by azole-resistant A. fumigatus strains were recently reevaluated by an international expert panel, which concluded that drug resistance testing of cultured isolates is highly indicated when antifungal therapy is intended. In geographical regions with a high environmental prevalence of azole-resistant strains, initial therapy should be guided by such analyses. More environmental and clinical screening studies are therefore needed to generate the local epidemiologic data if such measures are to be implemented on a sound basis. Here we propose a first workflow for evaluating isolates from screening studies, and we compile the MIC values correlating with individual amino acid substitutions in the products of cyp51 genes for interpretation of DNA sequencing data, especially in the absence of cultured isolates.
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36
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Jeanvoine A, Rocchi S, Reboux G, Crini N, Crini G, Millon L. Azole-resistantAspergillus fumigatusin sawmills of Eastern France. J Appl Microbiol 2017; 123:172-184. [DOI: 10.1111/jam.13488] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 04/05/2017] [Accepted: 05/03/2017] [Indexed: 11/28/2022]
Affiliation(s)
- A. Jeanvoine
- Parasitology-Mycology Department; University Hospital; Besançon France
| | - S. Rocchi
- Parasitology-Mycology Department; University Hospital; Besançon France
- Chrono-Environnement UMR 6249 CNRS; Bourgogne Franche-Comté University; Besançon France
| | - G. Reboux
- Parasitology-Mycology Department; University Hospital; Besançon France
- Chrono-Environnement UMR 6249 CNRS; Bourgogne Franche-Comté University; Besançon France
| | - N. Crini
- Chrono-Environnement UMR 6249 CNRS; Bourgogne Franche-Comté University; Besançon France
| | - G. Crini
- Chrono-Environnement UMR 6249 CNRS; Bourgogne Franche-Comté University; Besançon France
| | - L. Millon
- Parasitology-Mycology Department; University Hospital; Besançon France
- Chrono-Environnement UMR 6249 CNRS; Bourgogne Franche-Comté University; Besançon France
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Abstract
Aspergillus spp. are important fungi because of the high mortality associated with aspergillosis. However, we have only three classes of anti-aspergillus drugs available; and only two drugs, itraconazole (ITCZ) and voriconazole (VRCZ), are available as oral agents in Japan. If azole-resistant Aspergillus causes chronic aspergillosis, we cannot treat such patients with oral azoles on an outpatient basis. As is the case with foreign countries, we found the existence of azole-resistant Aspergillus fumigatus in clinical settings in Japan. Resistance was attributed to mutations of the target protein (CYP51A). Additionally, we also found that long-term itraconazole treatment induced G54 substitution in CYP51A, causing itraconazole-resistance. Although there are few resistant Aspergillus strains existing in Japan now, we have to continue to find such resistant isolates, which are spreading worldwide.
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Affiliation(s)
- Masato Tashiro
- Department of Infectious Diseases, Nagasaki University Graduate School of Biomedical Sciences
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Abstract
Aspergillus species are ubiquitous fungal saprophytes found in diverse ecological niches worldwide. Among them, Aspergillus fumigatus is the most prevalent and is largely responsible for the increased incidence of invasive aspergillosis with high mortality rates in some immunocompromised hosts. Azoles are the first-line drugs in treating diseases caused by Aspergillus spp. However, increasing reports in A. fumigatus azole resistance, both in the clinical setting and in the environment, are threatening the effectiveness of clinical and agricultural azole drugs. The azole target is the 14-α sterol demethylase encoded by cyp51A gene and the main mechanisms of resistance involve the integration of tandem repeats in its promoter and/or single point mutations in this gene. In A. fumigatus, azole resistance can emerge in two different scenarios: a medical route in which azole resistance is generated during long periods of azole treatment in the clinical setting and a route of resistance derived from environmental origin due to extended use of demethylation inhibitors in agriculture. The understanding of A. fumigatus azole resistance development and its evolution is needed in order to prevent or minimize its impact. In this article, we review the current situation of azole resistance epidemiology and the predominant molecular mechanisms described based on the resistance acquisition routes. In addition, the clinical implications of A. fumigatus azole resistance and future research are discussed.
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Epidemiology and Molecular Characterizations of Azole Resistance in Clinical and Environmental Aspergillus fumigatus Isolates from China. Antimicrob Agents Chemother 2016; 60:5878-84. [PMID: 27431231 DOI: 10.1128/aac.01005-16] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 07/14/2016] [Indexed: 11/20/2022] Open
Abstract
Azole resistance in Aspergillus fumigatus has emerged as a worldwide public health problem. We sought here to demonstrate the occurrence and characteristics of azole resistance in A. fumigatus from different parts of China. A total of 317 clinical and 144 environmental A. fumigatus isolates from 12 provinces were collected and subjected to screening for azole resistance. Antifungal susceptibility, cyp51A gene sequencing, and genotyping were carried out for all suspected azole-resistant isolates and a subset of azole-susceptible isolates. As a result, 8 (2.5%) clinical and 2 (1.4%) environmental A. fumigatus isolates were identified as azole resistant. Five azole-resistant strains exhibit the TR34/L98H mutation, whereas four carry the TR34/L98H/S297T/F495I mutation in the cyp51A gene. Genetic typing and phylogenetic analysis showed that there was a worldwide clonal expansion of the TR34/L98H isolates, while the TR34/L98H/S297T/F495I isolates from China harbored a distinct genetic background with resistant isolates from other countries. High polymorphisms existed in the cyp51A gene that produced amino acid changes among azole-susceptible A. fumigatus isolates, with N248K being the most common mutation. These data suggest that the wide distribution of azole-resistant A. fumigatus might be attributed to the environmental resistance mechanisms in China.
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40
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Mair WJ, Deng W, Mullins JGL, West S, Wang P, Besharat N, Ellwood SR, Oliver RP, Lopez-Ruiz FJ. Demethylase Inhibitor Fungicide Resistance in Pyrenophora teres f. sp. teres Associated with Target Site Modification and Inducible Overexpression of Cyp51. Front Microbiol 2016; 7:1279. [PMID: 27594852 PMCID: PMC4990540 DOI: 10.3389/fmicb.2016.01279] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 08/03/2016] [Indexed: 12/18/2022] Open
Abstract
Pyrenophora teres f. sp. teres is the cause of net form of net blotch (NFNB), an economically important foliar disease in barley (Hordeum vulgare). Net and spot forms of net blotch are widely controlled using site-specific systemic fungicides. Although resistance to succinate dehydrogenase inhibitors and quinone outside inhibitors has been addressed before in net blotches, mechanisms controlling demethylation inhibitor resistance have not yet been reported at the molecular level. Here we report the isolation of strains of NFNB in Australia since 2013 resistant to a range of demethylase inhibitor fungicides. Cyp51A:KO103-A1, an allele with the mutation F489L, corresponding to the archetype F495I in Aspergillus fumigatus, was only present in resistant strains and was correlated with resistance factors to various demethylase inhibitors ranging from 1.1 for epoxiconazole to 31.7 for prochloraz. Structural in silico modeling of the sensitive and resistant CYP51A proteins docked with different demethylase inhibitor fungicides showed how the interaction of F489L within the heme cavity produced a localized constriction of the region adjacent to the docking site that is predicted to result in lower binding affinities. Resistant strains also displayed enhanced induced expression of the two Cyp51A paralogs and of Cyp51B genes. While Cyp51B was found to be constitutively expressed in the absence of fungicide, Cyp51A was only detected at extremely low levels. Under fungicide induction, expression of Cyp51B, Cyp51A2, and Cyp51A1 was shown to be 1.6-, 3,- and 5.3-fold higher, respectively in the resistant isolate compared to the wild type. These increased levels of expression were not supported by changes in the promoters of any of the three genes. The implications of these findings on demethylase inhibitor activity will require current net blotch management strategies to be reconsidered in order to avoid the development of further resistance and preserve the lifespan of fungicides in use.
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Affiliation(s)
- Wesley J Mair
- Department of Environment and Agriculture, Centre for Crop and Disease Management, Curtin University Bentley, WA, Australia
| | - Weiwei Deng
- Department of Environment and Agriculture, Centre for Crop and Disease Management, Curtin University Bentley, WA, Australia
| | | | - Samuel West
- Institute of Life Science, School of Medicine, Swansea University Swansea, UK
| | - Penghao Wang
- School of Veterinary and Life Sciences, Murdoch University Murdoch, WA, Australia
| | - Naghmeh Besharat
- Department of Environment and Agriculture, Centre for Crop and Disease Management, Curtin University Bentley, WA, Australia
| | - Simon R Ellwood
- Department of Environment and Agriculture, Centre for Crop and Disease Management, Curtin University Bentley, WA, Australia
| | - Richard P Oliver
- Department of Environment and Agriculture, Centre for Crop and Disease Management, Curtin University Bentley, WA, Australia
| | - Francisco J Lopez-Ruiz
- Department of Environment and Agriculture, Centre for Crop and Disease Management, Curtin University Bentley, WA, Australia
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Triazole Resistance in Aspergillus spp.: A Worldwide Problem? J Fungi (Basel) 2016; 2:jof2030021. [PMID: 29376938 PMCID: PMC5753134 DOI: 10.3390/jof2030021] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Revised: 06/22/2016] [Accepted: 06/24/2016] [Indexed: 11/16/2022] Open
Abstract
Since the first description of an azole-resistant A. fumigatus strain in 1997, there has been an increasing number of papers describing the emergence of azole resistance. Firstly reported in the USA and soon after in Europe, it has now been described worldwide, challenging the management of human aspergillosis. The main mechanism of resistance is the modification of the azole target enzyme: 14-α sterol demethylase, encoded by the cyp51A gene; although recently, other resistance mechanisms have also been implicated. In addition, a shift in the epidemiology has been noted with other Aspergillus species (mostly azole resistant) increasingly being reported as causative agents of human disease. This paper reviews the current situation of Aspergillus azole resistance and its implications in the clinical setting.
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Bernal-Martínez L, Alastruey-Izquierdo A, Cuenca-Estrella M. Diagnostics and susceptibility testing in Aspergillus. Future Microbiol 2016; 11:315-28. [PMID: 26848512 DOI: 10.2217/fmb.15.140] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
UNLABELLED Invasive aspergillosis is a major cause of morbidity and mortality in immunosuppressed patients. Early diagnosis and correct antifungal treatment have a direct impact on patient survival. A number of newer diagnostic procedures have been developed as alternatives to conventional microbiological methods. The detection of fungal components, largely antigens and DNA, are used in clinical laboratories to diagnose invasive aspergillosis. Other rapid diagnostic tests have been recently developed with promising results. However, antifungal resistance is becoming an emerging problem. The detection of this resistance is important to administer the proper antifungal agent. This text reviews the novelties on new diagnostics Aspergillus spp. PROCEDURES Intrinsic antifungal resistance and mechanisms of secondary resistance to triazoles in A. fumigatus are also reviewed.
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Affiliation(s)
- Leticia Bernal-Martínez
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain; Spanish Network for the Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, Spain
| | - Ana Alastruey-Izquierdo
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain; Spanish Network for the Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, Spain
| | - Manuel Cuenca-Estrella
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain; Spanish Network for the Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, Spain
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43
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Liu M, Zheng N, Li D, Zheng H, Zhang L, Ge H, Liu W. cyp51A-based mechanism of azole resistance in Aspergillus fumigatus: Illustration by a new 3D Structural Model of Aspergillus fumigatus CYP51A protein. Med Mycol 2016; 54:400-8. [PMID: 26768370 DOI: 10.1093/mmy/myv102] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 11/15/2015] [Indexed: 01/29/2023] Open
Abstract
Mutations of CYP51A protein (Cytochrome P450 14-α Sterol demethylase) play a central role in the azole resistance of Aspergillus fumigatus The available structural models of CYP51A protein ofA. fumigatus are built based on that of Homo sapiens and that of Mycobacterium tuberculosis, of which the amino acid homology is only 38% and 29% compared with CYP51A protein ofA. fumigatus, respectively. In the present study, we constructed a new 3D structural model ofA. fumigatus CYP51A protein based on a recently resolved crystal structure of the homologous protein in the fungus S. cerevisiae, which shares 50% amino acid homology with A. fumigatus CYP51A protein. Three azole molecules, itraconazole, voriconazole, and posaconazole, were docked to the wild-type and the mutant A. fumigatus CYP51A protein models, respectively, to illustrate the impact of cyp51A mutations to azole-resistance. We found the mutations that occurred at L98, M220, and Y431 positions would decrease the binding affinity of azoles to the CYP51A protein and therefore would reduce their inhibitory effects. Additionally, the mutations of L98 and G432 would reduce the stability of the protein, which might lead to conformational change of its binding pocket and eventually the resistance to azoles.
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Affiliation(s)
- Musang Liu
- Department of Medical Mycology, Institute of Dermatology, Chinese Academy of Medical Science and Peking Union Medical College, Nanjing, Jiangsu, China Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, China
| | - Nan Zheng
- Medical School, Nanjing University, Nanjing, Jiangsu, China
| | - Dongmei Li
- Department of Medical Mycology, Institute of Dermatology, Chinese Academy of Medical Science and Peking Union Medical College, Nanjing, Jiangsu, China Georgetown University Medical Center, Department of Microbiology and Immunology, Washington DC, Washington, United States
| | - Hailin Zheng
- Department of Medical Mycology, Institute of Dermatology, Chinese Academy of Medical Science and Peking Union Medical College, Nanjing, Jiangsu, China Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, China
| | - Lili Zhang
- Department of Medical Mycology, Institute of Dermatology, Chinese Academy of Medical Science and Peking Union Medical College, Nanjing, Jiangsu, China Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, China
| | - Hu Ge
- The Institute of Medicinal Plant Development, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Weida Liu
- Department of Medical Mycology, Institute of Dermatology, Chinese Academy of Medical Science and Peking Union Medical College, Nanjing, Jiangsu, China Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Nanjing, China
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44
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Rocchi S, Reboux G, Millon L. [Azole resistance with environmental origin: What alternatives for the future?]. J Mycol Med 2015; 25:249-56. [PMID: 26631951 DOI: 10.1016/j.mycmed.2015.10.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Revised: 10/08/2015] [Accepted: 10/12/2015] [Indexed: 01/25/2023]
Abstract
Azole resistant Aspergillus fumigatus strains are increasingly reported in many countries. One resistance mechanism is attributed to the use of azole fungicides in environment. Two mutations, TR34/L98H and TR46/Y121F/T289A, on the cyp51A gene, have been described. Results of 40 publications about azole resistant strain detections, with TR34/L98H and TR46/Y121F/T289A mutations, in clinical and/or environmental samples, are presented in this review. These cases, observed in many countries, suggest spreading phenomenon. Measures to moderate fungicides treatments and/or alternative treatments in environment should be established to preserve the effectiveness of azole antifungal therapy for at-risk patients.
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Affiliation(s)
- S Rocchi
- Laboratoire de parasitologie-mycologie, centre hospitalier régional universitaire Jean-Minjoz, 25000 Besançon, France; UMR 6249 CNRS chrono-environnement, université de Bourgogne Franche-Comté, 25000 Besançon, France.
| | - G Reboux
- Laboratoire de parasitologie-mycologie, centre hospitalier régional universitaire Jean-Minjoz, 25000 Besançon, France; UMR 6249 CNRS chrono-environnement, université de Bourgogne Franche-Comté, 25000 Besançon, France
| | - L Millon
- Laboratoire de parasitologie-mycologie, centre hospitalier régional universitaire Jean-Minjoz, 25000 Besançon, France; UMR 6249 CNRS chrono-environnement, université de Bourgogne Franche-Comté, 25000 Besançon, France
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