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Tsai DJ, Hsieh LY, Chung PJ, Chen YZ, Jhou YJ, Tseng KY, Yang CJ, Yeh YC, Lin SY, Shin-Jung Lee S, Wu TI, Chiang TT, Chou CH, Miu WC, Liu PY, Lu CT, Lee YT, Syu YL, Hsu GJ, Chen YC, Lee NY, Chen CH, Yang CC, Wang LS, Liu JW, Kao CC, Chang YT, Liu KS, Hu BS, Hsu CH, Huang YC, Lo HJ. Surveillance of pathogenic yeasts in hospital environments in Taiwan in 2020. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2024:S1684-1182(24)00156-7. [PMID: 39271437 DOI: 10.1016/j.jmii.2024.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 08/26/2024] [Accepted: 08/28/2024] [Indexed: 09/15/2024]
Abstract
BACKGROUND A predominate azole-resistant Candida tropicalis clade 4 genotype causing candidemia has been detected in not only Taiwan but also China, Singapore, and Australia. It can also be detected on fruit surfaces. In addition to determining distribution and drug susceptibilities of pathogenic yeasts in environments of intensive care units of 25 hospitals in Taiwan, we would also like to investigate whether the azole-resistant C. tropicalis exists in Taiwan's hospital environment. METHODS The swabs of hospital environments were collected from August to November in 2020 and were cultured for yeasts. The yeasts were identified by rDNA sequence and the antifungal susceptibilities of those isolates were determined by the broth microdilution method. RESULTS The average yeast-culture rate of hospitals was 9.4% (217/2299). Sinks had the highest yeast-positive culture rate (32.7%), followed by bedside tables (28.9%), floors (26.0%), water-dispenser buttons (23.8%), and TV controller/touch panels (19.0%). Of 262 identified isolates, Candida parapsilosis was the most common species, accounting for 22.1%, followed by Filobasidium uniguttulatum (18.3%), Candida albicans (9.5%), C. tropicalis (8.0%), Candida glabrata (Nakaseomyces glabratus) (6.9%), and 30 other species (35.1%). Of the 21 C. tropicalis isolates from 11 units in 9 hospitals, 15 diploid sequence types (DSTs) were identified. The two DST506 fluconazole-resistant ones belonged to clade 4. CONCLUSION We detected not only various pathogenic yeast species but also the predominant clade 4 genotype of azole-resistant C. tropicalis. Our findings highlight and re-emphasize the importance of regular cleaning and disinfection practices.
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Affiliation(s)
- De-Jiun Tsai
- Taiwan Mycology Reference Center, National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli County, Taiwan
| | - Li-Yun Hsieh
- Taiwan Mycology Reference Center, National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli County, Taiwan
| | - Pei-Jung Chung
- Taiwan Mycology Reference Center, National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli County, Taiwan
| | - Yin-Zhi Chen
- Taiwan Mycology Reference Center, National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli County, Taiwan
| | - Yi-Jyun Jhou
- Taiwan Mycology Reference Center, National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli County, Taiwan
| | - Kuo-Yun Tseng
- Taiwan Mycology Reference Center, National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli County, Taiwan
| | - Chia-Jui Yang
- Department of Internal Medicine, Far Eastern Memorial Hospital, New Taipei, Taiwan
| | - Yen-Cheng Yeh
- Division of Infectious Disease, Department of Medicine, Kaohsiung Armed Forces General Hospital, Kaohsiung, Taiwan
| | - Seng-Yi Lin
- Division of Infectious Diseases, Department of Internal Medicine, Camillians Saint Mary's Hospital Luodong, Yilan County, Taiwan
| | - Susan Shin-Jung Lee
- Division of Infectious Diseases, Department of Internal Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
| | - Ting-I Wu
- Department of Internal Medicine, Cathay General Hospital, Taipei, Taiwan
| | - Tsung-Ta Chiang
- Division of Infection, Department of Internal Medicine, Tri-Service General Hospital, Taipei, Taiwan
| | - Chien-Hsuan Chou
- Department of Internal Medicine, Sin Lau Hospital, The Presbyterian Church of Taiwan, Tainan, Taiwan
| | - Wei-Chieh Miu
- Section of Infectious Diseases, Mennonite Christian Hospital, Hualien, Taiwan
| | - Po-Yu Liu
- Division of Infection, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan
| | - Chin-Te Lu
- Department of Infectious Diseases, Lo-Hsu Medical Foundation, Lotung Poh-Ai Hospital, Yilan County, Taiwan
| | - Yuan-Ti Lee
- School of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Yu-Ling Syu
- Infection Control Office, Hua-Lien Hospital, Ministry of Health and Welfare, Hualien, Taiwan
| | - Gwo-Jong Hsu
- Department of Internal Medicine, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi, Taiwan
| | - Yee-Chun Chen
- Center for Infection Control, National Taiwan University Hospital, Taipei, Taiwan
| | - Nan-Yao Lee
- Division of Infectious Disease, Department of Internal Medicine and Center for Infection Control, National Cheng Kung University Hospital, Tainan, Taiwan
| | - Chang-Hua Chen
- Section of Infectious Diseases, Department of Internal Medicine, Changhua Christian Hospital, Changhua County, Taiwan
| | - Ching-Cheng Yang
- Department of Infectious Diseases, Kuang Tien General Hospital, Taichung, Taiwan
| | - Lih-Shinn Wang
- Division of Infectious Diseases, Department of Internal Medicine, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan
| | - Jien-Wei Liu
- Division of Infectious Diseases, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | - Chin-Chuan Kao
- Division of Infectious Disease, Department of Internal Medicine, Tungs' Taichung Metroharbor Hospital, Taichung, Taiwan
| | - Ya-Ting Chang
- Division of Infectious Diseases, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - Keh-Sen Liu
- Division of Infectious Diseases, Department of Internal Medicine, Show Chwan Memorial Hospital, Changhua, Taiwan
| | - Bor-Shen Hu
- Section of Infectious Diseases, Department of Internal Medicine, Taipei City Hospital, Heping Branch, Taipei, Taiwan
| | - Che-Han Hsu
- Division of Infectious Diseases, Cheng Ching Hospital Chung Kang Branch, Taichung, Taiwan
| | - Yi-Ching Huang
- Division of Infectious Diseases, Jen-Ai Hospital, Taichung, Taiwan
| | - Hsiu-Jung Lo
- Taiwan Mycology Reference Center, National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli County, Taiwan; Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu, Taiwan; School of Dentistry, China Medical University, Taichung, Taiwan.
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Feng Y, Lu H, Whiteway M, Jiang Y. Understanding fluconazole tolerance in Candida albicans: implications for effective treatment of candidiasis and combating invasive fungal infections. J Glob Antimicrob Resist 2023; 35:314-321. [PMID: 37918789 DOI: 10.1016/j.jgar.2023.10.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 10/07/2023] [Accepted: 10/22/2023] [Indexed: 11/04/2023] Open
Abstract
OBJECTIVES Fluconazole (FLC) tolerant phenotypes in Candida species contribute to persistent candidemia and the emergence of FLC resistance. Therefore, making FLC fungicidal and eliminating FLC tolerance are important for treating invasive fungal diseases (IFDs) caused by Candida species. However, the mechanisms of FLC tolerance in Candida species remain to be fully explored. METHODS This review discusses the high incidence of FLC tolerance in Candida species and the importance of successfully clearing FLC tolerance in treating candidiasis. We further define and characterize FLC tolerance in C. albicans. RESULTS This review identifies global factors affecting FLC tolerance and suggest that FLC tolerance is a strategy of C. albicans response to FLC damage whose mechanism differs from FLC resistance. CONCLUSIONS This review highlights the significance of the cell membrane and cell wall integrity in FLC tolerance, guiding approaches to combat IFDs caused by Candida species..
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Affiliation(s)
- Yanru Feng
- Department of Pharmacy, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Hui Lu
- Department of Pharmacy, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China
| | | | - Yuanying Jiang
- Department of Pharmacy, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China.
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3
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Alabi PE, Gautier C, Murphy TP, Gu X, Lepas M, Aimanianda V, Sello JK, Ene IV. Small molecules restore azole activity against drug-tolerant and drug-resistant Candida isolates. mBio 2023; 14:e0047923. [PMID: 37326546 PMCID: PMC10470600 DOI: 10.1128/mbio.00479-23] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Accepted: 04/13/2023] [Indexed: 06/17/2023] Open
Abstract
Each year, fungi cause more than 1.5 billion infections worldwide and have a devastating impact on human health, particularly in immunocompromised individuals or patients in intensive care units. The limited antifungal arsenal and emerging multidrug-resistant species necessitate the development of new therapies. One strategy for combating drug-resistant pathogens is the administration of molecules that restore fungal susceptibility to approved drugs. Accordingly, we carried out a screen to identify small molecules that could restore the susceptibility of pathogenic Candida species to azole antifungals. This screening effort led to the discovery of novel 1,4-benzodiazepines that restore fluconazole susceptibility in resistant isolates of Candida albicans, as evidenced by 100-1,000-fold potentiation of fluconazole activity. This potentiation effect was also observed in azole-tolerant strains of C. albicans and in other pathogenic Candida species. The 1,4-benzodiazepines selectively potentiated different azoles, but not other approved antifungals. A remarkable feature of the potentiation was that the combination of the compounds with fluconazole was fungicidal, whereas fluconazole alone is fungistatic. Interestingly, the potentiators were not toxic to C. albicans in the absence of fluconazole, but inhibited virulence-associated filamentation of the fungus. We found that the combination of the potentiators and fluconazole significantly enhanced host survival in a Galleria mellonella model of systemic fungal infection. Taken together, these observations validate a strategy wherein small molecules can restore the activity of highly used anti-infectives that have lost potency. IMPORTANCE In the last decade, we have been witnessing a higher incidence of fungal infections, due to an expansion of the fungal species capable of causing disease (e.g., Candida auris), as well as increased antifungal drug resistance. Among human fungal pathogens, Candida species are a leading cause of invasive infections and are associated with high mortality rates. Infections by these pathogens are commonly treated with azole antifungals, yet the expansion of drug-resistant isolates has reduced their clinical utility. In this work, we describe the discovery and characterization of small molecules that potentiate fluconazole and restore the susceptibility of azole-resistant and azole-tolerant Candida isolates. Interestingly, the potentiating 1,4-benzodiazepines were not toxic to fungal cells but inhibited their virulence-associated filamentous growth. Furthermore, combinations of the potentiators and fluconazole decreased fungal burdens and enhanced host survival in a Galleria mellonella model of systemic fungal infections. Accordingly, we propose the use of novel antifungal potentiators as a powerful strategy for addressing the growing resistance of fungi to clinically approved drugs.
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Affiliation(s)
- Philip E. Alabi
- Department of Chemistry, Brown University, Providence, Rhode Island, USA
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, USA
| | - Cécile Gautier
- Institut Pasteur, Université Paris Cité, Fungal Heterogeneity Group, Paris, France
| | - Thomas P. Murphy
- Department of Molecular Microbiology and Immunology, Brown University, Providence, Rhode Island, USA
| | - Xilin Gu
- Department of Chemistry, Brown University, Providence, Rhode Island, USA
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, USA
| | - Mathieu Lepas
- Institut Pasteur, Université Paris Cité, CNRS UMR2000, Molecular Mycology Unit, Paris, France
| | - Vishukumar Aimanianda
- Institut Pasteur, Université Paris Cité, CNRS UMR2000, Molecular Mycology Unit, Paris, France
| | - Jason K. Sello
- Department of Chemistry, Brown University, Providence, Rhode Island, USA
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, USA
| | - Iuliana V. Ene
- Institut Pasteur, Université Paris Cité, Fungal Heterogeneity Group, Paris, France
- Department of Molecular Microbiology and Immunology, Brown University, Providence, Rhode Island, USA
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Bendary MM, Abd El-Hamid MI, Abousaty AI, Elmanakhly AR, Alshareef WA, Mosbah RA, Alhomrani M, Ghoneim MM, Elkelish A, Hashim N, Alamri AS, Al-Harthi HF, Safwat NA. Therapeutic Switching of Rafoxanide: a New Approach To Fighting Drug-Resistant Bacteria and Fungi. Microbiol Spectr 2023; 11:e0267922. [PMID: 37458598 PMCID: PMC10433953 DOI: 10.1128/spectrum.02679-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 06/05/2023] [Indexed: 08/19/2023] Open
Abstract
Control and management of life-threatening bacterial and fungal infections are a global health challenge. Despite advances in antimicrobial therapies, treatment failures for resistant bacterial and fungal infections continue to increase. We aimed to repurpose the anthelmintic drug rafoxanide for use with existing therapeutic drugs to increase the possibility of better managing infection and decrease treatment failures. For this purpose, we evaluated the antibacterial and antifungal potential of rafoxanide. Notably, 70% (70/100) of bacterial isolates showed multidrug resistance (MDR) patterns, with higher prevalence among human isolates (73.5% [50/68]) than animal ones (62.5% [20/32]). Moreover, 22 fungal isolates (88%) were MDR and were more prevalent among animal (88.9%) than human (87.5%) sources. We observed alarming MDR patterns among bacterial isolates, i.e., Klebsiella pneumoniae (75% [30/40; 8 animal and 22 human]) and Escherichia coli (66% [40/60; 12 animal and 28 human]), and fungal isolates, i.e., Candida albicans (86.7% [13/15; 4 animal and 9 human]) and Aspergillus fumigatus (90% [9/10; 4 animal and 5 human]), that were resistant to at least one agent in three or more different antimicrobial classes. Rafoxanide had antibacterial and antifungal activities, with minimal inhibitory concentration (MICs) ranging from 2 to 128 μg/mL. Rafoxanide at sub-MICs downregulated the mRNA expression of resistance genes, including E. coli and K. pneumoniae blaCTX-M-1, blaTEM-1, blaSHV, MOX, and DHA, C. albicans ERG11, and A. fumigatus cyp51A. We noted the improvement in the activity of β-lactam and antifungal drugs upon combination with rafoxanide. This was apparent in the reduction in the MICs of cefotaxime and fluconazole when these drugs were combined with sub-MIC levels of rafoxanide. There was obvious synergism between rafoxanide and cefotaxime against all E. coli and K. pneumoniae isolates (fractional inhibitory concentration index [FICI] values ≤ 0.5). Accordingly, there was a shift in the patterns of resistance of 16.7% of E. coli and 22.5% of K. pneumoniae isolates to cefotaxime and those of 63.2% of C. albicans and A. fumigatus isolates to fluconazole when the isolates were treated with sub-MICs of rafoxanide. These results were confirmed by in silico and mouse protection assays. Based on the in silico study, one possible explanation for how rafoxanide reduced bacterial resistance is through its inhibitory effects on bacterial and fungal histidine kinase enzymes. In short, rafoxanide exhibited promising results in overcoming bacterial and fungal drug resistance. IMPORTANCE The drug repurposing strategy is an alternative approach to reducing drug development timelines with low cost, especially during outbreaks of disease caused by drug-resistant pathogens. Rafoxanide can disrupt the abilities of bacterial and fungal cells to adapt to stress conditions. The coadministration of antibiotics with rafoxanide can prevent the failure of treatment of both resistant bacteria and fungi, as the resistant pathogens could be made sensitive upon treatment with rafoxanide. From our findings, we anticipate that pharmaceutical companies will be able to utilize new combinations against resistant pathogens.
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Affiliation(s)
- Mahmoud M. Bendary
- Department of Microbiology and Immunology, Faculty of Pharmacy, Port Said University, Port Said, Egypt
| | - Marwa I. Abd El-Hamid
- Department of Microbiology, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt
| | - Amira I. Abousaty
- Department of Microbiology, Faculty of Science, Zagazig University, Zagazig, Egypt
| | - Arwa R. Elmanakhly
- Department of Microbiology and Immunology, Faculty of Pharmacy, Modern University for Technology and Information, Cairo, Egypt
| | - Walaa A. Alshareef
- Department of Microbiology and Immunology, Faculty of Pharmacy, October 6 University, 6th of October, Egypt
| | - Rasha A. Mosbah
- Infection Control Unit, Zagazig University Hospital, Zagazig, Egypt
| | - Majid Alhomrani
- Department of Clinical Laboratories Sciences, The Faculty of Applied Medical Science, Taif University, Taif, Saudi Arabia
- Centre of Biomedical Science Research, Deanship of Scientific Research, Taif University, Taif, Saudi Arabia
| | - Mohammed M. Ghoneim
- Department of Pharmacy Practice, College of Pharmacy, Al Maarefa University, Ad Diriyah, Saudi Arabia
| | - Amr Elkelish
- Biology Department, College of Science, Imam Mohammad ibn Saud Islamic University, Riyadh, Saudi Arabia
- Botany and Microbiology Department, Faculty of Science, Suez Canal University, Ismailia, Egypt
| | - Nada Hashim
- Faculty of Medicine, University of Gezira, Wad Medani, Sudan
| | - Abdulhakeem S. Alamri
- Department of Clinical Laboratories Sciences, The Faculty of Applied Medical Science, Taif University, Taif, Saudi Arabia
- Centre of Biomedical Science Research, Deanship of Scientific Research, Taif University, Taif, Saudi Arabia
| | - Helal F. Al-Harthi
- Biology Department, Turabah University College, Taif University, Taif, Saudi Arabia
| | - Nesreen A. Safwat
- Department of Microbiology and Immunology, Faculty of Pharmacy, Modern University for Technology and Information, Cairo, Egypt
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Lara-Aguilar V, Rueda C, García-Barbazán I, Varona S, Monzón S, Jiménez P, Cuesta I, Zaballos Á, Zaragoza Ó. Adaptation of the emerging pathogenic yeast Candida auris to high caspofungin concentrations correlates with cell wall changes. Virulence 2021; 12:1400-1417. [PMID: 34180774 PMCID: PMC8244764 DOI: 10.1080/21505594.2021.1927609] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 04/15/2021] [Accepted: 04/30/2021] [Indexed: 11/13/2022] Open
Abstract
Candida auris has emerged as a fungal pathogen that causes nosocomial outbreaks worldwide. Diseases caused by this fungus are of concern, due to its reduced susceptibility to several antifungals. C. auris exhibits paradoxical growth (PG; defined as growth at high, but not intermediate antifungal concentrations) in the presence of caspofungin (CPF). We have characterized the cellular changes associated with adaptation to CPF. Using EUCAST AFST protocols, all C. auris isolates tested showed PG to CPF, although in some isolates it was more prominent. Most isolates also showed a trailing effect (TE) to micafungin and anidulafungin. We identified two FKS genes in C. auris that encode the echinocandins target, namely β-1,3-glucan synthase. FKS1 contained the consensus hot-spot (HS) 1 and HS2 sequences. FKS2 only contained the HS1 region which had a change (F635Y), that has been shown to confer resistance to echinocandins in C. glabrata. PG has been characterized in other species, mainly C. albicans, where high CPF concentrations induced an increase in chitin, cell volume and aggregation. In C. auris CPF only induced a slight accumulation of chitin, and none of the other phenomena. RNAseq experiments demonstrated that CPF induced the expression of genes encoding several GPI-anchored cell wall proteins, membrane proteins required for the stability of the cell wall, chitin synthase and mitogen-activated protein kinases (MAPKs) involved in cell integrity, such as BCK2, HOG1 and MKC1 (SLT2). Our work highlights some of the processes induced in C. auris to adapt to echinocandins.
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Affiliation(s)
- Violeta Lara-Aguilar
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto De Salud Carlos III, Madrid, Spain
| | - Cristina Rueda
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto De Salud Carlos III, Madrid, Spain
| | - Irene García-Barbazán
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto De Salud Carlos III, Madrid, Spain
| | - Sarai Varona
- Bioinformatics Unit, Core Scientific and Technical Units, Instituto De Salud Carlos III, Madrid, Spain
| | - Sara Monzón
- Bioinformatics Unit, Core Scientific and Technical Units, Instituto De Salud Carlos III, Madrid, Spain
| | - Pilar Jiménez
- Genomics Unit, Core Scientific and Technical Units, Instituto De Salud Carlos III, Madrid, Spain
| | - Isabel Cuesta
- Bioinformatics Unit, Core Scientific and Technical Units, Instituto De Salud Carlos III, Madrid, Spain
| | - Ángel Zaballos
- Genomics Unit, Core Scientific and Technical Units, Instituto De Salud Carlos III, Madrid, Spain
| | - Óscar Zaragoza
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto De Salud Carlos III, Madrid, Spain
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Mechanisms of Azole Resistance and Trailing in Candida tropicalis Bloodstream Isolates. J Fungi (Basel) 2021; 7:jof7080612. [PMID: 34436151 PMCID: PMC8396981 DOI: 10.3390/jof7080612] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 07/25/2021] [Accepted: 07/26/2021] [Indexed: 12/13/2022] Open
Abstract
Objectives: Azole-resistant Candida tropicalis has emerged in Asia in the context of its trailing nature, defined by residual growth above minimum inhibitory concentrations (MICs). However, limited investigations in C. tropicalis have focused on the difference of genotypes and molecular mechanisms between these two traits. Methods: Sixty-four non-duplicated C. tropicalis bloodstream isolates collected in 2017 were evaluated for azole MICs by the EUCAST E.def 7.3.1 method, diploid sequence type (DST) by multilocus sequencing typing, and sequences and expression levels of genes encoding ERG11, its transcription factor, UPC2, and efflux pumps (CDR1, CDR2 and MDR1). Results: Isavuconazole showed the highest in vitro activity and trailing against C. tropicalis, followed by voriconazole and fluconazole (geometric mean [GM] MIC, 0.008, 0.090, 1.163 mg/L, respectively; trailing GM, 27.4%, 20.8% and 19.5%, respectively; both overall p < 0.001). Fourteen (21.9%) isolates were non-WT to fluconazole/voriconazole, 12 of which were non-WT to isavuconazole and clustered in clonal complex (CC) 3. Twenty-five (39.1%) isolates were high trailing WT, including all CC2 isolates (44.0%) (containing DST140 and DST98). All azole non-WT isolates carried the ERG11 mutations A395T/W and/or C461T/Y, and most carried the UPC2 mutation T503C/Y. These mutations were not identified in low and high trailing WT isolates. Azole non-WT and high trailing WT isolates exhibited the highest expression levels of ERG11 and MDR1, 3.91- and 2.30-fold, respectively (both overall p < 0.01). Conclusions: Azole resistance and trailing are phenotypically and genotypically different in C. tropicalis. Interference with azole binding and MDR1 up-regulation confer azole resistance and trailing, respectively.
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Sitterlé E, Coste AT, Obadia T, Maufrais C, Chauvel M, Sertour N, Sanglard D, Puel A, D'Enfert C, Bougnoux ME. Large-scale genome mining allows identification of neutral polymorphisms and novel resistance mutations in genes involved in Candida albicans resistance to azoles and echinocandins. J Antimicrob Chemother 2021; 75:835-848. [PMID: 31923309 DOI: 10.1093/jac/dkz537] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 11/22/2019] [Accepted: 12/01/2019] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND The genome of Candida albicans displays significant polymorphism. Point mutations in genes involved in resistance to antifungals may either confer phenotypic resistance or be devoid of phenotypic consequences. OBJECTIVES To catalogue polymorphisms in azole and echinocandin resistance genes occurring in susceptible strains in order to rapidly pinpoint relevant mutations in resistant strains. METHODS Genome sequences from 151 unrelated C. albicans strains susceptible to fluconazole and caspofungin were used to create a catalogue of non-synonymous polymorphisms in genes involved in resistance to azoles (ERG11, TAC1, MRR1 and UPC2) or echinocandins (FKS1). The potential of this catalogue to reveal putative resistance mutations was tested in 10 azole-resistant isolates, including 1 intermediate to caspofungin. Selected mutations were analysed by mutagenesis experiments or mutational prediction effect. RESULTS In the susceptible strains, we identified 126 amino acid substitutions constituting the catalogue of phenotypically neutral polymorphisms. By excluding these neutral substitutions, we identified 22 additional substitutions in the 10 resistant strains. Among these substitutions, 10 had already been associated with resistance. The remaining 12 were in Tac1p (n = 6), Upc2p (n = 2) and Erg11p (n = 4). Four out of the six homozygous substitutions in Tac1p (H263Y, A790V, H839Y and P971S) conferred increases in azole MICs, while no effects were observed for those in Upc2p. Additionally, two homozygous substitutions (Y64H and P236S) had a predicted conformation effect on Erg11p. CONCLUSIONS By establishing a catalogue of neutral polymorphisms occurring in genes involved in resistance to antifungal drugs, we provide a useful resource for rapid identification of mutations possibly responsible for phenotypic resistance in C. albicans.
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Affiliation(s)
- Emilie Sitterlé
- Unité Biologie et Pathogénicité Fongiques, Département de Mycologie, Institut Pasteur, USC2019 INRA, Paris, France.,Université Paris Diderot, Sorbonne Paris Cité, Paris, France.,Unité de Parasitologie-Mycologie, Service de Microbiologie clinique, Hôpital Necker-Enfants-Malades, Assistance Publique des Hôpitaux de Paris (APHP), Paris, France
| | - Alix T Coste
- Institut de Microbiologie, Université de Lausanne et Centre Hospitalo-Universitaire, Lausanne, Switzerland
| | - Thomas Obadia
- Hub de Bioinformatique et Biostatistique, Département Biologie Computationnelle, Institut Pasteur, USR 3756 CNRS, Paris, France.,Unité Malaria: parasites et hôtes, Département Parasites et Insectes Vecteurs, Institut Pasteur, Paris, France
| | - Corinne Maufrais
- Hub de Bioinformatique et Biostatistique, Département Biologie Computationnelle, Institut Pasteur, USR 3756 CNRS, Paris, France
| | - Murielle Chauvel
- Unité Biologie et Pathogénicité Fongiques, Département de Mycologie, Institut Pasteur, USC2019 INRA, Paris, France
| | - Natacha Sertour
- Unité Biologie et Pathogénicité Fongiques, Département de Mycologie, Institut Pasteur, USC2019 INRA, Paris, France
| | - Dominique Sanglard
- Institut de Microbiologie, Université de Lausanne et Centre Hospitalo-Universitaire, Lausanne, Switzerland
| | - Anne Puel
- Laboratoire de génétique humaine des maladies infectieuses, Necker, INSERM U1163, Paris, France.,Université Paris Descartes, Institut Imagine, Paris, France
| | - Christophe D'Enfert
- Unité Biologie et Pathogénicité Fongiques, Département de Mycologie, Institut Pasteur, USC2019 INRA, Paris, France
| | - Marie-Elisabeth Bougnoux
- Unité Biologie et Pathogénicité Fongiques, Département de Mycologie, Institut Pasteur, USC2019 INRA, Paris, France.,Unité de Parasitologie-Mycologie, Service de Microbiologie clinique, Hôpital Necker-Enfants-Malades, Assistance Publique des Hôpitaux de Paris (APHP), Paris, France.,Université de Paris, Paris, France
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Judan Cruz KG, Alfonso ED, Fernando SID, Watanabe K. Candida albicans Biofilm Inhibition by Ethnobotanicals and Ethnobotanically-Synthesized Gold Nanoparticles. Front Microbiol 2021; 12:665113. [PMID: 34108950 PMCID: PMC8180598 DOI: 10.3389/fmicb.2021.665113] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Accepted: 04/20/2021] [Indexed: 01/12/2023] Open
Abstract
The virulence and drug resistance of globally prevalent Candida albicans has presented complications toward its control while advances in effective antivirulence drugs remain critical. Emerging methods are now being evaluated to facilitate development of novel therapeutic approaches against this pathogen. This study focuses on the biofilm formation inhibition of ethnobotanical crude extracts and the use of nanotechnology through the ethnobotanically-synthesized gold nanoparticles to control C. albicans. Control on biofilm formation was compared using crude extracts (CEs) and biologically synthesized gold nanoparticles (CEs + AuNPs). Significantly lower biofilm formation was exhibited in thirteen (13) CEs and fourteen (14) CEs + AuNPs. Biofilm-linked genes Bcr1 and HSP90 expression were consequently downregulated. Higher biofilm inhibition activity was noted in some CEs + AuNPs compared to its counterpart CEs. This study emphasizes the biofilm inhibition activity of ethnobotanicals and the use of nanoparticles to enhance delivery of compounds, and points to its prospects for developing anti-pathogenic drugs without evolving resistance.
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Affiliation(s)
- Khristina G Judan Cruz
- Department of Biological Sciences, College of Science, Central Luzon State University, Science City of Muñoz, Nueva Ecija, Philippines
| | - Eleonor D Alfonso
- College of Agriculture, Nueva Ecija University of Science and Technology, Nueva Ecija, Philippines
| | - Somar Israel D Fernando
- Department of Biological Sciences, College of Science, Central Luzon State University, Science City of Muñoz, Nueva Ecija, Philippines
| | - Kozo Watanabe
- Department of Civil and Environmental Engineering, Ehime University, Matsuyama, Japan.,Center for Marine Environmental Studies (CMES), Ehime University, Matsuyama, Japan
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9
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Nishimoto AT, Sharma C, Rogers PD. Molecular and genetic basis of azole antifungal resistance in the opportunistic pathogenic fungus Candida albicans. J Antimicrob Chemother 2021; 75:257-270. [PMID: 31603213 DOI: 10.1093/jac/dkz400] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Candida albicans is an opportunistic yeast and the major human fungal pathogen in the USA, as well as in many other regions of the world. Infections with C. albicans can range from superficial mucosal and dermatological infections to life-threatening infections of the bloodstream and vital organs. The azole antifungals remain an important mainstay treatment of candidiasis and therefore the investigation and understanding of the evolution, frequency and mechanisms of azole resistance are vital to improving treatment strategies against this organism. Here the organism C. albicans and the genetic changes and molecular bases underlying the currently known resistance mechanisms to the azole antifungal class are reviewed, including up-regulated expression of efflux pumps, changes in the expression and amino acid composition of the azole target Erg11 and alterations to the organism's typical sterol biosynthesis pathways. Additionally, we update what is known about activating mutations in the zinc cluster transcription factor (ZCF) genes regulating many of these resistance mechanisms and review azole import as a potential contributor to azole resistance. Lastly, investigations of azole tolerance in C. albicans and its implicated clinical significance are reviewed.
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Affiliation(s)
- Andrew T Nishimoto
- Department of Clinical Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Cheshta Sharma
- Department of Clinical Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
| | - P David Rogers
- Department of Clinical Pharmacy, University of Tennessee Health Science Center, Memphis, TN, USA
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10
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Tagle-Olmedo T, Andrade-Pavón D, Martínez-Gamboa A, Gómez-García O, García-Sierra F, Hernández-Rodríguez C, Villa-Tanaca L. Inhibitors of DNA topoisomerases I and II applied to Candida dubliniensis reduce growth, viability, the generation of petite mutants and toxicity, while acting synergistically with fluconazole. FEMS Yeast Res 2021; 21:6219866. [PMID: 33837766 DOI: 10.1093/femsyr/foab023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 04/07/2021] [Indexed: 11/14/2022] Open
Abstract
The increasing resistance of Candida species to azoles emphasizes the urgent need for new antifungal agents with novel mechanisms of action. The aim of this study was to examine the effect of three DNA topoisomerase inhibitors of plant origin (camptothecin, etoposide and curcumin) on the growth of Candida dubliniensis. The phylogenetic analysis showed a close relationship between the topoisomerase enzymes of C. dubliniensis and Candida albicans. The alignment of the amino acid sequences of topoisomerase I and II of yeasts and humans evidenced conserved domains. The docking study revealed affinity of the test compounds for the active site of topoisomerase I and II in C. dubliniensis. Curcumin and camptothecin demonstrated a stronger in vitro antifungal effect than the reference drugs (fluconazole and itraconazole). Significant synergistic activity between the topoisomerase inhibitors and fluconazole at the highest concentration (750 µM) was observed. Fluconazole induced the petite phenotype to a greater degree than the topoisomerase inhibitors, indicating a tendency to generate resistance. Lower toxicity was found for such inhibitors versus reference drugs on Galleria mellonella larva. The topoisomerase inhibitors exhibited promising antifungal activity, and the DNA topoisomerase enzymes of C. dubliniensis proved to be an excellent model for evaluating new antifungal compounds.
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Affiliation(s)
- Tania Tagle-Olmedo
- Laboratorio de Biología Molecular de Bacterias y Levaduras, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prol. de Carpio y Plan de Ayala. Col. Sto. Tomás, 11340 México City, México
| | - Dulce Andrade-Pavón
- Laboratorio de Biología Molecular de Bacterias y Levaduras, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prol. de Carpio y Plan de Ayala. Col. Sto. Tomás, 11340 México City, México
- Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Av. Wilfrido Massieu S/N Unidad Profesional "Adolfo López Mateos", Zacatenco. Col. Lindavista, Venustiano Carranza, Del, CP 07700, D.F., México
| | - Areli Martínez-Gamboa
- Laboratorio de Microbiología Clínica, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, 15 Vasco de Quiroga Ave, Belisario Domínguez Sección XVI, Tlalpan, México City, Mexico
| | - Omar Gómez-García
- Departamento de Química Orgánica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prol. de Carpio y Plan de Ayala. Col. Sto. Tomás, 11340 México City, México
| | - Francisco García-Sierra
- Departamento de Biología Celular, Centro de investigación y estudios avanzados del Instituto Politécnico Nacional (CINVESTAV), México City, México
| | - César Hernández-Rodríguez
- Laboratorio de Biología Molecular de Bacterias y Levaduras, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prol. de Carpio y Plan de Ayala. Col. Sto. Tomás, 11340 México City, México
| | - Lourdes Villa-Tanaca
- Laboratorio de Biología Molecular de Bacterias y Levaduras, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prol. de Carpio y Plan de Ayala. Col. Sto. Tomás, 11340 México City, México
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11
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Levinson T, Dahan A, Novikov A, Paran Y, Berman J, Ben-Ami R. Impact of tolerance to fluconazole on treatment response in Candida albicans bloodstream infection. Mycoses 2020; 64:78-85. [PMID: 33000505 DOI: 10.1111/myc.13191] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 09/04/2020] [Indexed: 01/05/2023]
Abstract
BACKGROUND Treatment of Candida albicans bloodstream infection with fluconazole is associated with significant mortality despite in vitro susceptibility to the drug. OBJECTIVES We sought to determine whether tolerance to fluconazole is predictive of treatment failure. METHODS We reviewed patients with monomicrobial C albicans bloodstream infection who received primary monotherapy with fluconazole. Tolerance to fluconazole, defined as the fraction of growth above the MIC, was quantified using the disc diffusion assay and digital image analyses. Survival analyses were performed with host and treatment factors as predictive variables. RESULTS Among 44 patients included in the study, all-cause mortality was 29.5% at 30 days and 43.1% at 12 weeks. Forty-one isolates (93%) were susceptible to fluconazole (MIC50, 0.5 mg/L). Fluconazole tolerance was strongly associated with death for patients treated with fluconazole within 24 h of candidemia onset (33.3% vs 0%; p = .007), but not among patients whose treatment was started later. MIC did not correlate with survival, regardless of treatment delay. A Cox regression model including time to treatment, tolerance to fluconazole, fluconazole exposure and Pitt bacteraemia score provided good prediction of treatment outcome (area under the receiver-operator curve, 0.82). CONCLUSIONS In patients with C albicans bloodstream infection, tolerance testing was predictive of fluconazole efficacy if the drug was started early. Further study is required to validate the utility of this metric to guide treatment choices.
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Affiliation(s)
- Tal Levinson
- Infectious Diseases Unit, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Alon Dahan
- The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Anna Novikov
- Infectious Diseases Unit, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Yael Paran
- Infectious Diseases Unit, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Judith Berman
- The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Ronen Ben-Ami
- Infectious Diseases Unit, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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12
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Monroy-Pérez E, Rodríguez-Bedolla RM, Garzón J, Vaca-Paniagua F, Arturo-Rojas Jiménez E, Paniagua-Contreras GL. Marked virulence and azole resistance in Candida albicans isolated from patients with periodontal disease. Microb Pathog 2020; 148:104436. [PMID: 32781099 DOI: 10.1016/j.micpath.2020.104436] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 07/19/2020] [Accepted: 08/02/2020] [Indexed: 01/12/2023]
Abstract
Candida albicans is an opportunistic fungus frequently associated with periodontal diseases. The objective of this study was to determine the expression patterns of virulence genes associated with those of azole resistance among the strains of C. albicans isolated from patients with periodontal disease. We isolated 80 strains of C. albicans from patients with periodontal disease enrolled from two dental clinics and their antifungal susceptibilities were evaluated using the disc diffusion method. C. albicans and its virulence genes were identified using PCR. The expressions of the virulence genes of C. albicans were analyzed using real-time PCR post in vitro infection of the cell line A549. The phenotype for resistance against azoles such as ketoconazole and fluconazole was observed in all analyzed strains (n = 80), which coincided with the high frequency of occurrence of the genes CDR1 and MDR1 associated with resistance. The frequencies of detection and expression of the genes HWP1 (47/15), ALS1 (80/66), ALS3 (70/30), LIP1 (78/44), LIP4 (77/65), LIP5 (79/58), LIP6 (79/58), PLB1 (79/65), and PLB2 (80/66) were found to be higher in the strains of C. albicans isolated from patients with moderate periodontitis and different expression patterns associated with those for azole resistance were identified. It could be elucidated that the high expression of virulence markers associated with azole resistance in C. albicans might be contributing to the chronicity of periodontal infections.
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Affiliation(s)
- Eric Monroy-Pérez
- Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México. Av. de Los Barrios 1, Los Reyes Iztacala, Tlalnepantla, Estado de México, 54090, Mexico.
| | - Rosa María Rodríguez-Bedolla
- Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México. Av. de Los Barrios 1, Los Reyes Iztacala, Tlalnepantla, Estado de México, 54090, Mexico
| | - Javier Garzón
- Clínica de Endoperiodontología, FES Iztacala, Universidad Nacional Autónoma de México, Mexico
| | - Felipe Vaca-Paniagua
- Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México. Av. de Los Barrios 1, Los Reyes Iztacala, Tlalnepantla, Estado de México, 54090, Mexico; Laboratorio Nacional en Salud, Diagnóstico Molecular y Efecto Ambiental en Enfermedades Crónico-Degenerativas, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Mexico; Subdirección de investigación Básica, Instituto Nacional de Cancerología, CDMX, 14080, Mexico
| | - Ernesto Arturo-Rojas Jiménez
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Mexico
| | - Gloria Luz Paniagua-Contreras
- Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México. Av. de Los Barrios 1, Los Reyes Iztacala, Tlalnepantla, Estado de México, 54090, Mexico.
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13
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Zare-Khafri M, Alizadeh F, Nouripour-Sisakht S, Khodavandi A, Gerami M. Inhibitory effect of magnetic iron-oxide nanoparticles on the pattern of expression of lanosterol 14 α-demethylase ( ERG11) in fluconazole-resistant colonising isolate of Candida albicans. IET Nanobiotechnol 2020; 14:375-381. [PMID: 32691739 DOI: 10.1049/iet-nbt.2019.0354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fluconazole-resistant Candida albicans is a big scary reality. The authors assessed the antifungal effects of magnetic iron-oxide nanoparticles on fluconazole-resistant colonising isolate of C. albicans and determined the expression of ERG11 gene, protein sequence similarity and ergosterol content. C. albicans isolates were characterised and fluconazole resistance is recognised using World Health Organization's WHONET software. Susceptibility testing of magnetic iron-oxide nanoparticles against fluconazole-resistant colonising isolate of C. albicans was performed according to Clinical and Laboratory Standards Institute guidelines. The expression patterns of ERG11 and protein sequence similarity were investigated. Ergosterol quantification has been used to gauge the antifungal activity of magnetic iron-oxide nanoparticles. The findings indicated that 93% of C. albicans isolates were resistant to fluconazole. Magnetic iron-oxide nanoparticles were presented activity against fluconazole-resistant colonising isolate of C. albicans with minimum inhibitory concentration at 250-500 µg/ml. The expression level of ERG11 gene was downregulated in fluconazole-resistant colonising isolate of C. albicans. The results revealed no differences in fluconazole-resistant colonising isolate of C. albicans by comparison with ERG11 reference sequences. Moreover, significant reduction was noted in ergosterol content. The findings shed a novel light on the application of magnetic iron-oxide nanoparticles in fighting against resistant C. albicans.
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Affiliation(s)
- Mohammad Zare-Khafri
- Department of Microbiology, Yasooj Branch, Islamic Azad University, Yasooj, Iran
| | - Fahimeh Alizadeh
- Department of Microbiology, Yasooj Branch, Islamic Azad University, Yasooj, Iran
| | | | - Alireza Khodavandi
- Department of Biology, Gachsaran Branch, Islamic Azad University, Gachsaran, Iran.
| | - Majid Gerami
- Education Research Centre, Yasuj University, Yasuj, Iran
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14
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Hauzer M, Cohen MJ, Polacheck I, Moses A, Korem M. The prevalence and clinical significance of microcolonies when tested according to contemporary interpretive breakpoints for fluconazole against Candida species using E-test. Med Mycol 2020; 57:718-723. [PMID: 30576514 DOI: 10.1093/mmy/myy130] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 10/28/2018] [Accepted: 11/06/2018] [Indexed: 12/21/2022] Open
Abstract
Changes in the interpretive-breakpoints for antifungals against various Candida species have raised the need to examine the significance of the phenomenon of the growth of microcolonies in agar diffusion inhibition zones, which has generally been considered negligible. The objective was to determine the incidence of cases in which microcolonies demonstrate fluconazole resistance according to current interpretive-breakpoints and whether their growth is associated with therapeutic failure. The fluconazole minimum inhibitory concentrations (MICs) of 100 blood culture isolates of Candida were performed by E-test on Roswell Park Memorial Institute (RPMI) agar and examined for the appearance of microcolonies. Fluconazole MICs of microcolonies were then determined over three generations. The significance of the phenomenon of microcolonies was determined according to clinical data retrieved from electronic files. Microcolonies were a common phenomenon among Candida isolates following incubation on RPMI agar, with a higher frequency among C. albicans isolates as compared to non-albicans Candida across generations (57-93% vs 31-93%, respectively) and a similar fluconazole susceptibility rate over three generations. The rate of microcolonies was similar in both patients with successful and unsuccessful outcome (41% vs 42%, respectively). Microcolonies are a common phenomenon. No increase in MIC was demonstrated throughout three generations of microcolony inoculation on RPMI, and no difference in clinical outcome was observed.
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Affiliation(s)
- Michael Hauzer
- Department of Clinical Microbiology and Infectious Diseases, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | | | - Itzhack Polacheck
- Department of Clinical Microbiology and Infectious Diseases, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Allon Moses
- Department of Clinical Microbiology and Infectious Diseases, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Maya Korem
- Department of Clinical Microbiology and Infectious Diseases, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
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15
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Khan SH, Younus H, Allemailem KS, Almatroudi A, Alrumaihi F, Alruwetei AM, Alsahli MA, Khan A, Khan MA. Potential of Methylglyoxal-Conjugated Chitosan Nanoparticles in Treatment of Fluconazole-Resistant Candida albicans Infection in a Murine Model. Int J Nanomedicine 2020; 15:3681-3693. [PMID: 32547022 PMCID: PMC7261666 DOI: 10.2147/ijn.s249625] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 05/04/2020] [Indexed: 12/11/2022] Open
Abstract
Background Fungal infections are becoming more prevalent and threatening because of the continuous emergence of azole-resistant fungal infections. The present study was aimed to assess the activity of free Methylglyoxal (MG) or MG-conjugated chitosan nanoparticles (MGCN) against fluconazole-resistant Candida albicans. Materials and Methods A novel formulation of MGCN was prepared and characterized to determine their size, shape and polydispersity index. Moreover, the efficacy of fluconazole or MG or MGCN was determined against intracellular C. albicans in macrophages and the systematic candidiasis in a murine model. The safety of MG or MGCN was tested in mice by analyzing the levels of hepatic and renal toxicity parameters. Results Candida albicans did not respond to fluconazole, even at the highest dose of 20 mg/kg, whereas MG and MGCN effectively eliminated C. albicans from the macrophages and infected mice. Mice in the group treated with MGCN at a dose of 10 mg/kg exhibited a 90% survival rate and showed the lowest fungal load in the kidney, whereas the mice treated with free MG at the same dose exhibited 50% survival rate. Moreover, the administration of MG or MGCN did not induce any liver and kidney toxicity in the treated mice. Conclusion The findings of the present work suggest that MGCN may be proved a promising therapeutic formulation to treat azole-resistant C. albicans infections.
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Affiliation(s)
- Shaheer Hasan Khan
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002, India
| | - Hina Younus
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002, India
| | - Khaled S Allemailem
- Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraidah 51452, Saudi Arabia
| | - Ahmad Almatroudi
- Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraidah 51452, Saudi Arabia
| | - Faris Alrumaihi
- Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraidah 51452, Saudi Arabia
| | - Abdulmohsen M Alruwetei
- Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraidah 51452, Saudi Arabia
| | - Mohammed A Alsahli
- Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraidah 51452, Saudi Arabia
| | - Arif Khan
- Department of Basic Health Sciences, College of Applied Medical Sciences, Qassim University, Buraidah, 51452, Saudi Arabia
| | - Masood Alam Khan
- Department of Basic Health Sciences, College of Applied Medical Sciences, Qassim University, Buraidah, 51452, Saudi Arabia
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16
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In Vitro Antifungal and Antivirulence Activities of Biologically Synthesized Ethanolic Extract of Propolis-Loaded PLGA Nanoparticles against Candida albicans. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2019; 2019:3715481. [PMID: 31871479 PMCID: PMC6907039 DOI: 10.1155/2019/3715481] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 10/18/2019] [Accepted: 11/01/2019] [Indexed: 12/15/2022]
Abstract
Propolis is a natural substance and consists of bioactive compounds, which gives it antioxidant and antimicrobial properties. However, the use of propolis is limited by the low solubility in aqueous solutions. Thus, nanoparticles may be likely to accomplish enhanced delivery of poorly water-soluble phytomedicine. The aim of the present study was to fabricate and evaluate the biological activity of ethanolic extract of propolis-loaded poly(lactic-co-glycolic acid) nanoparticles (EEP-NPs). The EEP-NPs were prepared using the oil-in-water (o/w) single-emulsion solvent evaporation technique. The physicochemical properties of EEP-NPs were characterized and tested on their cytotoxicity, antifungal activity, and impact on key virulence factors that contribute to pathogenesis of C. albicans. EEP-NPs were successfully synthesized and demonstrated higher antifungal activity than EEP in free form. Moreover, EEP-NPs exhibited less cytotoxicity on Vero cells and suppressed the virulence factors of C. albicans, including adhesion, hyphal germination, biofilm formation, and invasion. Importantly, EEP-NPs exhibited a statistical decrease in the expression of hyphal adhesion-related genes, ALS3 and HWP1, of C. albicans. The results of this study revealed that EEP-NPs mediates a potent anticandidal activity and key virulence factors by reducing the gene-encoding virulence-associated hyphal- adhesion proteins of C. albicans and, thereby, disrupting the morphologic presence and attenuating their virulence.
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17
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Minimal Inhibitory Concentration (MIC)-Phenomena in Candida albicans and Their Impact on the Diagnosis of Antifungal Resistance. J Fungi (Basel) 2019; 5:jof5030083. [PMID: 31487830 PMCID: PMC6787722 DOI: 10.3390/jof5030083] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 08/30/2019] [Accepted: 09/02/2019] [Indexed: 02/07/2023] Open
Abstract
Antifungal susceptibility testing (AFST) of clinical isolates is a tool in routine diagnostics to facilitate decision making on optimal antifungal therapy. The minimal inhibitory concentration (MIC)-phenomena (trailing and paradoxical effects (PXE)) observed in AFST complicate the unambiguous and reproducible determination of MICs and the impact of these phenomena on in vivo outcome are not fully understood. We aimed to link the MIC-phenomena with in vivo treatment response using the alternative infection model Galleria mellonella. We found that Candida albicans strains exhibiting PXE for caspofungin (CAS) had variable treatment outcomes in the Galleria model. In contrast, C. albicans strains showing trailing for voriconazole failed to respond in vivo. Caspofungin- and voriconazole-susceptible C. albicans strains responded to the respective antifungal therapy in vivo. In conclusion, MIC data and subsequent susceptibility interpretation of strains exhibiting PXE and/or trailing should be carried out with caution, as both effects are linked to drug adaptation and treatment response is uncertain to predict.
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18
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Khan MA, Aldebasi YH, Alsuhaibani SA, AlSahli MA, Alzohairy MA, Khan A, Younus H. Therapeutic potential of thymoquinone liposomes against the systemic infection of Candida albicans in diabetic mice. PLoS One 2018; 13:e0208951. [PMID: 30589842 PMCID: PMC6320018 DOI: 10.1371/journal.pone.0208951] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 11/27/2018] [Indexed: 12/12/2022] Open
Abstract
The present study was aimed to develop a liposomal formulation of thymoquinone (Lip-TQ) to treat Candida albicans infection in diabetic mice. Streptozotocin (STZ) was injected to induce hyperglycemia and on day 3 post STZ administration, mice were intravenously infected with C. albicans. Various doses (2, 5 and 10 mg/kg) of Free or Lip-TQ were administered in C. albicans infected diabetic mice. The effect of Lip-TQ was also determined on the organ indices, liver and kidney function parameters. Lip-TQ at a dose of 10 mg/kg significantly reduced the level of the blood glucose and alleviated the systemic C. albicans infection in diabetic mice. C. albicans infected diabetic mice treated with Lip-TQ at a dose of 10 mg/kg showed the survival rate of 70% as compared to that of 20% in the group treated with free TQ. The treatment with Lip-TQ resulted in the recovery of the organ indices, liver inflammation, kidney functioning and pancreas regeneration in diabetic mice. Moreover, TQ formulations also showed the direct therapeutic effect against candidiasis in the untreated or metformin-treated diabetic mice. Therefore, the findings of the present study support the use of Lip-TQ in the treatment of candidiasis in the diabetic patients.
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Affiliation(s)
- Masood A Khan
- College of Applied Medical Sciences, Qassim University, Buraydah, Saudi Arabia
| | - Yousef H Aldebasi
- College of Applied Medical Sciences, Qassim University, Buraydah, Saudi Arabia
| | | | - Mohammed A AlSahli
- College of Applied Medical Sciences, Qassim University, Buraydah, Saudi Arabia
| | | | - Arif Khan
- College of Applied Medical Sciences, Qassim University, Buraydah, Saudi Arabia
| | - Hina Younus
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India
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19
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Implications of the EUCAST Trailing Phenomenon in Candida tropicalis for the In Vivo Susceptibility in Invertebrate and Murine Models. Antimicrob Agents Chemother 2018; 62:AAC.01624-18. [PMID: 30224538 DOI: 10.1128/aac.01624-18] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 09/05/2018] [Indexed: 12/31/2022] Open
Abstract
Candida tropicalis isolates often display reduced but persistent growth (trailing) over a broad fluconazole concentration range during EUCAST susceptibility testing. Whereas weak trailing (<25% of the positive growth control) is common and found not to impair fluconazole efficacy, we investigated if more pronounced trailing impacted treatment efficacy. Fluconazole efficacy against two weakly (≤25% growth), two moderately (26% to 50% growth), and one heavily (>70% growth) trailing resistant isolate and one resistant (100% growth) isolate were investigated in vitro and in vivo (in a Galleria mellonella survival model and two nonlethal murine models). CDR1 expression levels and ERG11 sequences were characterized. The survival in fluconazole-treated G. mellonella was inversely correlated with the degree of trailing (71% to 9% survival in treatment groups). In mice, resistant and heavily trailing isolates responded poorly to fluconazole treatment. CDR1 expression was significantly higher in trailing and resistant isolates than in wild-type isolates (1.4-fold to 10-fold higher). All isolates exhibited ERG11 wild-type alleles. Heavily trailing isolates were less responsive to fluconazole in all in vivo models, indicating an impact on fluconazole efficacy. CDR1 upregulation may have contributed to the observed differences. Moderately trailing isolates responded less well to fluconazole in larvae only. This confirms clinical data suggesting fluconazole is effective against infections with such isolates in less severely ill patients and supports the current 50% growth endpoint for susceptibility testing. However, it is still unclear if the gradual loss of efficacy observed for moderately trailing isolates in the larva model may be a reason for concern in selected vulnerable patient populations.
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Gucwa K, Kusznierewicz B, Milewski S, Van Dijck P, Szweda P. Antifungal Activity and Synergism with Azoles of Polish Propolis. Pathogens 2018; 7:pathogens7020056. [PMID: 29921833 PMCID: PMC6027192 DOI: 10.3390/pathogens7020056] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 06/05/2018] [Accepted: 06/13/2018] [Indexed: 11/16/2022] Open
Abstract
The aim of our work was to check if one of the products of natural origin, namely honey bee propolis, may be an alternative or supplement to currently used antifungal agents. The activity of 50 ethanolic extracts of propolis (EEPs), harvested in Polish apiaries, was tested on a group of 69 clinical isolates of C. albicans. Most of the EEPs showed satisfactory activity, with minimum fungicidal concentrations (MFC) mainly in the range of 0.08⁻1.25% (v/v). Eradication of biofilm from polystyrene microtitration plates in 50% (MBEC50, Minimum Biofilm Eradication Concentration) required concentrations in the range of 0.04% (v/v) to more than 1.25% (v/v). High activity was also observed in eradication of biofilm formed by C. glabrata and C. krusei on the surfaces of PVC (Polyvinyl Chloride) and silicone catheters. EEPs at subinhibitory concentrations inhibited yeast-to-mycelia morphological transformation of C. albicans in liquid medium and mycelial growth on solid medium. A synergistic effect was observed for the action of EEP in combination with fluconazole (FLU) and voriconazole (VOR) against C. albicans. In the presence of EEP at concentrations as low as 0.02%, the MICs of FLU and VOR were 256 to 32 times lower in comparison to those of the drug alone. Evidence for the fungal cell membrane as the most probable target of EEPs are presented.
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Affiliation(s)
- Katarzyna Gucwa
- Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza 11/12 Str., 80-233 Gdańsk, Poland.
| | - Barbara Kusznierewicz
- Department of Chemistry, Technology and Biotechnology of Food, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza 11/12 Str., 80-233 Gdańsk, Poland.
| | - Sławomir Milewski
- Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza 11/12 Str., 80-233 Gdańsk, Poland.
| | - Patrick Van Dijck
- VIB-KU Leuven Center for Microbiology, Kasteelpark Arenberg 31 bus 2438, 3001 Leuven, Belgium.
- Laboratory of Molecular Cell Biology, KU Leuven, Kasteelpark Arenberg 31, bus 2438, 3001 Leuven, Belgium.
| | - Piotr Szweda
- Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza 11/12 Str., 80-233 Gdańsk, Poland.
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Ni Q, Wang C, Tian Y, Dong D, Jiang C, Mao E, Peng Y. CgPDR1 gain-of-function mutations lead to azole-resistance and increased adhesion in clinical Candida glabrata strains. Mycoses 2018; 61:430-440. [PMID: 29464833 DOI: 10.1111/myc.12756] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 02/13/2018] [Accepted: 02/14/2018] [Indexed: 12/30/2022]
Abstract
Recently, Candida glabrata has emerged as a health-threatening pathogen and the rising resistance to antifungal agent in C. glabrata often leads to clinical treatment failure. To investigate the evolution of drug resistance and adherence ability in four paired clinical isolates collected before and after antifungal treatment. Sequence analysis, gene disruption, drug-susceptibility, adhesion tests and real-time quantitative PCR were performed. The azole-susceptible strains acquired azole resistance after antifungal therapy. Four gain-of-function (GOF) mutations in CgPDR1 were revealed by sequence analysis, namely G1099D, G346D, L344S and P927S, the last being reported for the first time. CDR1, CDR2 and SNQ2 efflux pump gene expression levels were elevated in strains harbouring GOF mutations in CgPDR1, resulting in decreased azole susceptibility. CgPDR1 alleles with distinct GOF mutations displayed different expression profiles for the drug-related genes. CgPDR1GOF mutations led to increased efflux pumps expression levels in a strain background independent way. Hyperactive Pdr1G1099D and Pdr1P927S displayed strain background-dependent increased adherence to host cells via upregulation of EPA1 transcription. Interestingly, the drug transporter gene expression levels did not always correspond with that of the adhesin EPA1 gene. GOF mutations in CgPDR1 conferred drug resistance and increased adherence in the clinical strains, possibly endowing C. glabrata with increased viability and pathogenicity.
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Affiliation(s)
- Qi Ni
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Chen Wang
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yuan Tian
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Danfeng Dong
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Cen Jiang
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Enqiang Mao
- Department of Emergency Intensive Care Unit, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yibing Peng
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
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Nabili M, Moazeni M, Hedayati MT, Aryamlo P, Abdollahi Gohar A, Madani SM, Fathi H. Glabridin induces overexpression of two major apoptotic genes, MCA1 and NUC1 , in Candida albicans. J Glob Antimicrob Resist 2017; 11:52-56. [DOI: 10.1016/j.jgar.2017.08.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Revised: 07/05/2017] [Accepted: 08/09/2017] [Indexed: 02/01/2023] Open
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Xisto MIDS, Caramalho RDF, Rocha DAS, Ferreira-Pereira A, Sartori B, Barreto-Bergter E, Junqueira ML, Lass-Flörl C, Lackner M. Pan-azole-resistant Candida tropicalis carrying homozygous erg11 mutations at position K143R: a new emerging superbug? J Antimicrob Chemother 2017; 72:988-992. [PMID: 28065893 DOI: 10.1093/jac/dkw558] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 11/28/2016] [Indexed: 11/14/2022] Open
Abstract
Objectives Candidaemia is a public health problem mainly in hospitalized individuals worldwide. In Brazil, Candida albicans is the most prevalent species that causes candidaemia, followed by Candida tropicalis and Candida parapsilosis . Few data on the abundance of antifungal resistance are available for Latin America. Methods We analysed the frequency of azole and echinocandin resistance in Candida isolates ( n = 75) collected between 2012 and 2014 at the University Hospital of Federal University of Juiz de Fora (Brazil). The primary targets erg11 (azoles) and fks1 (echinocandins) were sequenced and modelled at the protein level. Antifungal susceptibility testing was performed according to CLSI (M27-A3 and M27-S4) and according to EUCAST. Results The three most frequent species were C. albicans (38.0%), C. tropicalis (30.0%) and Candida glabrata (17.0%). Azole resistance was observed in 27.0% of all Candida isolates, while 20.0% of all isolates were echinocandin resistant. A novel mutation in erg11 at location K143R was found to be associated with phenotypically pan-azole-resistant C. tropicalis isolates. This mutation maps near the active binding site of erg11 and is likely to confer pan-azole resistance to C. tropicalis . Conclusions A novel point mutation (K143R) located in the erg11 gene of C. tropicalis was found in pan-azole-resistant strains. According to our protein homology model, it is very likely that the mutation K143R causes pan-azole resistance in C. tropicalis . Moreover, an up-regulation of ABC transporters was observed, which can add up to a pan-azole-resistant phenotype.
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Affiliation(s)
- Mariana I D S Xisto
- Division of Hygiene and Medical Microbiology, Innsbruck Medical University, Innsbruck, Austria.,Laboratório de Química Biológica de Microorganismos, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Rita D F Caramalho
- Division of Hygiene and Medical Microbiology, Innsbruck Medical University, Innsbruck, Austria
| | - Débora A S Rocha
- Laboratório de Bioquímica Microbiana, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Antonio Ferreira-Pereira
- Laboratório de Bioquímica Microbiana, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Bettina Sartori
- Division of Hygiene and Medical Microbiology, Innsbruck Medical University, Innsbruck, Austria
| | - Eliana Barreto-Bergter
- Laboratório de Química Biológica de Microorganismos, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Maria L Junqueira
- Hospital Universitário, Universidade Federal de Juiz de Fora, Minas Gerais, Brazil
| | - Cornelia Lass-Flörl
- Division of Hygiene and Medical Microbiology, Innsbruck Medical University, Innsbruck, Austria
| | - Michaela Lackner
- Division of Hygiene and Medical Microbiology, Innsbruck Medical University, Innsbruck, Austria
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The Etest Performed Directly on Blood Culture Bottles Is a Reliable Tool for Detection of Fluconazole-Resistant Candida albicans Isolates. Antimicrob Agents Chemother 2017; 61:AAC.00400-17. [PMID: 28483951 DOI: 10.1128/aac.00400-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 04/28/2017] [Indexed: 11/20/2022] Open
Abstract
We assessed the ability of the Etest performed directly on positive blood cultures (ETDIR) to detect fluconazole susceptibility in 6 fluconazole-resistant and 12 fluconazole-susceptible Candida albicans isolates, according to CLSI M27-A3 and EUCAST EDef 7.2 procedures. Categorical agreement between ETDIR and broth microdilution was 100% when the trays were incubated at 25°C and trailing effect was ruled out. ETDIR is a reliable procedure when screening for the presence of fluconazole resistance in C. albicans.
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Paul-Satyaseela M, Hariharan P, Bharani T, Franklyne JS, Selvakumar T, Bharathimohan K, Kumar CV, Kachhadia V, Narayanan S, Rajagopal S, Balasubramanian G. Novel hydroxamates potentiated in vitro activity of fluconazole against Candida albicans. J Nat Sci Biol Med 2017; 8:119-124. [PMID: 28250687 PMCID: PMC5320813 DOI: 10.4103/0976-9668.198349] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A set of 12 novel hydroxamate compounds (NHCs), structurally designed as inhibitors of histone deacetylase (HDAC) enzyme, were synthesized at our facility. These were adamantane derivatives with N-hydroxyacetamide as pharmacophore, and each of these compounds was tested for potentiating activity on fluconazole. The concentration of fluconazole which completely inhibited (concentration of complete inhibition [CCI]) the growth of Candida albicans ATCC 90028 and C. albicans ATCC 64550 was determined by micro-dilution method in the absence and presence of NHCs. The CCI of fluconazole without the NHC combination was 64 μg/ml and 1024 μg/ml against C. albicans ATCC 90028 and C. albicans ATCC 64550, respectively. The majority of the NHCs potentiated the fluconazole activity markedly as CCI of fluconazole against C. albicans ATCC 90028 reduced to 0.25 μg/ml. Similarly, CCI of fluconazole against C. albicans ATCC 64550 reduced to 4–8 μg/ml in combination with majority of NHCs while the best activity was displayed by the compound 1 with a reduction of CCI to 0.5 μg/ml. The study results revealed the potential usage of hydroxamate derivatives, structurally designed as HDAC inhibitors to enhance the activity of fluconazole against C. albicans.
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Affiliation(s)
- Maneesh Paul-Satyaseela
- Drug Discovery Research, Orchid Pharma Ltd., Chennai, Tamil Nadu, India; Samrud Foundation for Health and Research/St. Martha's Hospital, Bengaluru, Karnataka, India
| | | | | | | | | | | | | | | | - Shridhar Narayanan
- Foundation for Neglected Disease Research, Sri Krishnadevaraya Research Centre, Sir M. Visvesvaraya Institute of Technology, Bengaluru, Karnataka, India
| | - Sridharan Rajagopal
- Jubilant Biosys Ltd., 96, Industrial Suburb 2nd Stage, Yeshwantpur, Bengaluru, Karnataka, India
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High Virulence and Antifungal Resistance in Clinical Strains of Candida albicans. CANADIAN JOURNAL OF INFECTIOUS DISEASES & MEDICAL MICROBIOLOGY 2016; 2016:5930489. [PMID: 28058052 PMCID: PMC5183749 DOI: 10.1155/2016/5930489] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 11/21/2016] [Indexed: 01/12/2023]
Abstract
Antifungal resistance and virulence properties of Candida albicans are a growing health problem worldwide. To study the expression of virulence and azole resistance genes in 39 clinical strains of C. albicans, we used a model of infection of human vaginal epithelial cells with C. albicans strains isolated from Mexican women with vulvovaginal candidiasis (VVC). The strains were identified by PCR amplification of the ITS1 and ITS2 regions of rRNA. The detection and expression of virulence genes and azole resistance genes MDR1 and CDR1 were performed using PCR and RT-PCR, respectively. All strains were sensitive to nystatin and 38 (97.4%) and 37 (94.9%) were resistant to ketoconazole and fluconazole, respectively. ALS1, SAP4–SAP6, LIP1, LIP2, LIP4, LIP6, LIP7, LIP9, LIP10, and PLB1-PLB2 were present in all strains; SAP1 was identified in 37 (94.8%) isolates, HWP1 in 35 (89.7%), ALS3 in 14 (35.8%), and CDR1 in 26 (66.6%). In nearly all of the strains, ALS1, HWP1, SAP4–SAP6, LIP1–LIP10, PLB1, and PLB2 were expressed, whereas CDR1 was expressed in 20 (51.3%) and ALS3 in 14 (35.8%). In our in vitro model of infection with C. albicans, the clinical strains showed different expression profiles of virulence genes in association with the azole resistance gene CDR1. The results indicate that the strains that infect Mexican patients suffering from VVC are highly virulent and virtually all are insensitive to azoles.
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Gohar AA, Badali H, Shokohi T, Nabili M, Amirrajab N, Moazeni M. Expression Patterns of ABC Transporter Genes in Fluconazole-Resistant Candida glabrata. Mycopathologia 2016; 182:273-284. [PMID: 27744635 DOI: 10.1007/s11046-016-0074-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 09/29/2016] [Indexed: 11/24/2022]
Abstract
Clinical management of fungal diseases is compromised by the emergence of antifungal drug resistance in fungi, which leads to elimination of available drug classes as treatment options. An understanding of antifungal resistance at molecular level is, therefore, essential for the development of strategies to combat the resistance. This study presents the assessment of molecular mechanisms associated with fluconazole resistance in clinical Candida glabrata isolates originated from Iran. Taking seven distinct fluconazole-resistant C. glabrata isolates, real-time PCRs were performed to evaluate the alternations in the regulation of the genes involved in drug efflux including CgCDR1, CgCDR2, CgSNQ2, and CgERG11. Gain-of-function (GOF) mutations in CgPDR1 alleles were determined by DNA sequencing. Cross-resistance to fluconazole, itraconazole, and voriconazole was observed in 2.5 % of the isolates. In the present study, six amino acid substitutions were identified in CgPdr1, among which W297R, T588A, and F575L were previously reported, whereas D243N, H576Y, and P915R are novel. CgCDR1 overexpression was observed in 57.1 % of resistant isolates. However, CgCDR2 was not co-expressed with CgCDR1. CgSNQ2 was upregulated in 71.4 % of the cases. CgERG11 overexpression does not seem to be associated with azole resistance, except for isolates that exhibited azole cross-resistance. The pattern of efflux pump gene upregulation was associated with GOF mutations observed in CgPDR1. These results showed that drug efflux mediated by adenosine-5-triphosphate (ATP)-binding cassette transporters, especially CgSNQ2 and CgCDR1, is the predominant mechanism of fluconazole resistance in Iranian isolates of C. glabrata. Since some novel GOF mutations were found here, this study also calls for research aimed at investigating other new GOF mutations to reveal the comprehensive understanding about efflux-mediated resistance to azole antifungal agents.
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Affiliation(s)
| | - Hamid Badali
- Invasive Fungi Research Centre, Mazandaran University of Medical Sciences, Sari, Iran.,Department of Medical Mycology and Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - Tahereh Shokohi
- Invasive Fungi Research Centre, Mazandaran University of Medical Sciences, Sari, Iran.,Department of Medical Mycology and Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - Mojtaba Nabili
- Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran.,Iranian Social Security Organization, Mazandaran, Iran
| | - Nasrin Amirrajab
- Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran.,Department of Laboratory Sciences, School of Paramedicine/Infectious and Tropical Diseases Research Centre, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Maryam Moazeni
- Invasive Fungi Research Centre, Mazandaran University of Medical Sciences, Sari, Iran. .,Department of Medical Mycology and Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.
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Evaluation of the possible influence of trailing and paradoxical effects on the clinical outcome of patients with candidemia. Clin Microbiol Infect 2016; 23:49.e1-49.e8. [PMID: 27677697 DOI: 10.1016/j.cmi.2016.09.016] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 08/05/2016] [Accepted: 09/20/2016] [Indexed: 11/24/2022]
Abstract
OBJECTIVE Paradoxical growth (PG) and trailing effect (TE) are frequently observed during antifungal susceptibility testing (AFST). These two phenomena interfere with the determination of the minimal inhibitory concentration (MIC). The aim of this study was to assess the clinical impact of TE and PG. METHODS We analysed the frequency of TE and PG of 690 Candida isolates collected from a population-based study performed in Spain (CANDIPOP) and correlated the results with clinical outcome of the patients. RESULTS Around 70% (484/690) of the isolates exhibited TE to azoles. Candida tropicalis showed the highest presence of TE (39/53 isolates exhibited residual growth >25% of control). No TE was seen in most of the isolates from the psilosis complex. PG was mainly associated with echinocandins. In patients treated with fluconazole within the first 48 hours after blood sampling (n = 221), the presence of TE to azoles tended to be associated with lower 30-day mortality (odds ratio (OR) 0.55, 95% confidence interval (CI) 0.25-1.00) but not with clinical failure (OR 0.85, 95% CI 0.45-1.54). In the subgroup of 117 patients treated with echinocandins, the presence of PG was not associated with patient's response to antifungal treatment (OR for 30-day mortality 1.63, 95% CI 0.76-4.03; OR for clinical failure 1.17, 95% CI 0.53-2.70). CONCLUSIONS TE or PG are widely expressed among Candida spp., although they do not seem to influence clinical outcome.
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Marcos-Zambrano LJ, Escribano P, Sánchez-Carrillo C, Bouza E, Guinea J. Scope and frequency of fluconazole trailing assessed using EUCAST in invasive Candida spp. isolates. Med Mycol 2016; 54:733-9. [PMID: 27161788 DOI: 10.1093/mmy/myw033] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 03/23/2016] [Indexed: 11/14/2022] Open
Abstract
Trailing is a well-known phenomenon that is defined as reduced but persistent visible growth of Candida spp. at fluconazole concentrations above the MIC. Trailing is commonly detected using the CLSI M27-A3 method, although little is known about its frequency when investigated with EUCAST. We assessed the frequency and scope of fluconazole trailing after using EUCAST EDef 7.2. against a large number of Candida spp. isolates from patients with candidemia. We studied 639 fluconazole-susceptible non-krusei Candida spp. isolates from 570 patients admitted to Gregorio Marañón Hospital. Isolates were tested in vitro for fluconazole susceptibility according to the EUCAST EDef 7.2 procedure; trailing was defined as the presence of any residual growth in wells containing fluconazole concentrations above the MIC. According to the mean percentage of trailing observed, isolates were classified as residual trailers (0.1-5%), slight trailers (6%-10%), moderate trailers (11%-15%), and heavy trailers (>15%). The relationship between trailing and genotyping was assessed. The mean overall percentage of trailing was 6.8%, with C. albicans and C. tropicalis showing the highest percentages (9.75% and 9.29%, respectively; P < .001). C. albicans and C. tropicalis had the highest percentage of heavy trailers (>15%). Trailing was not genotype-specific. Fluconazole trailing was observed frequently when EUCAST was used for antifungal susceptibility testing, particularly in isolates of C. albicans and C. tropicalis The cut-off proposed enabled us to classify the isolates according to the degree of trailing and can be used as the basis for future studies to evaluate the clinical impact of this phenomenon.
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Affiliation(s)
- Laura Judith Marcos-Zambrano
- Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
| | - Pilar Escribano
- Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain CIBER Enfermedades Respiratorias-CIBERES (CB06/06/0058), Madrid, Spain
| | - Carlos Sánchez-Carrillo
- Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain CIBER Enfermedades Respiratorias-CIBERES (CB06/06/0058), Madrid, Spain
| | - Emilio Bouza
- Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain CIBER Enfermedades Respiratorias-CIBERES (CB06/06/0058), Madrid, Spain Medicine Department, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain
| | - Jesús Guinea
- Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain CIBER Enfermedades Respiratorias-CIBERES (CB06/06/0058), Madrid, Spain Medicine Department, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain
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Alvarez-Rueda N, Fleury A, Logé C, Pagniez F, Robert E, Morio F, Le Pape P. The amino acid substitution N136Y in Candida albicans sterol 14alpha-demethylase is involved in fluconazole resistance. Med Mycol 2016; 54:764-775. [PMID: 27143634 DOI: 10.1093/mmy/myw023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Accepted: 03/24/2016] [Indexed: 12/22/2022] Open
Abstract
Resistance to fluconazole antifungal is an ongoing impediment to a successful treatment of Candida albicans infections. One of the most prevalent mechanisms leading to azole resistance is genetic alterations of the 14α-demethylase, the target of azole antifungals, through point mutations. Site-directed mutagenesis and molecular modeling of 14α-demethylase rationalize biological data about the role of protein substitutions in the azole treatment failure. In this work, we investigated the role of N136Y substitution by site-directed mutagenesis into Pichia pastoris guided by structural analysis. Single amino acid substitutions were created by site-directed mutagenesis into P. pastoris with C. albicans ERG11 gene as template. In vitro susceptibility of P. pastoris transformants expressing wild-type and mutants to azole compounds was determined by CLSI M27-A2 and spot agar methods. The fluconazole effect on ergosterol biosynthesis was analyzed by gas chromatography-mass spectrometry. By microdilution and spot tests, N136Y transformants showed a reduced in vitro susceptibility to fluconazole compared to wild-type controls. As expected, ergosterol/lanosterol ratios were higher in N136Y transformants compared to the wild-type controls after treatment with fluconazole. Molecular modeling suggests that residue Asn136 located within the first mutation hot spot, could play a role during heme and azole binding. These results provide new insights into the structural basis for 14α-demethylase-azole interaction and could guide the design of novel azole antifungals.
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Affiliation(s)
| | - Audrey Fleury
- Département de Parasitologie et de Mycologie Médicale
| | - Cédric Logé
- Laboratoire de Chimie Thérapeutique, Université de Nantes, Nantes Atlantique Universités, EA1155 - IICiMed, UFR des Sciences Pharmaceutiques et Biologiques, France
| | | | | | - Florent Morio
- Département de Parasitologie et de Mycologie Médicale.,Laboratoire de Parasitologie-Mycologie, CHU de Nantes, Nantes, France
| | - Patrice Le Pape
- Département de Parasitologie et de Mycologie Médicale.,Laboratoire de Parasitologie-Mycologie, CHU de Nantes, Nantes, France
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Zomorodian K, Bandegani A, Mirhendi H, Pakshir K, Alinejhad N, Poostforoush Fard A. In Vitro Susceptibility and Trailing Growth Effect of Clinical Isolates of Candida Species to Azole Drugs. Jundishapur J Microbiol 2016; 9:e28666. [PMID: 27127587 PMCID: PMC4841996 DOI: 10.5812/jjm.28666] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 10/10/2015] [Accepted: 11/30/2015] [Indexed: 01/12/2023] Open
Abstract
Background: Emergence of resistance to respective antifungal drugs is a primary concern for the treatment of candidiasis. Hence, determining antifungal susceptibility of the isolated yeasts is of special importance for effective therapy. For this purpose, the clinical laboratory standard institute (CLSI) has introduced a broth microdilution method to determine minimum inhibitory concentration (MIC). However, the so-called “Trailing effect” phenomenon might sometimes pose ambiguity in the interpretation of the results. Objectives: The present study aimed to determine the in vitro susceptibility of clinical isolates of Candida against azoles and the frequency of the Trailing effect. Materials and Methods: A total of 193 Candida isolates were prospectively collected and identified through the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Using a broth microdilution test, according to the guidelines of CLSI M27-A3, antifungal susceptibilities of the isolated yeasts against Fluconazole (FLU), Itraconazole (ITR), Ketoconazole (KET) and Voriconazole (VOR) were assessed. Moreover, trailing growth was determined when a susceptible MIC was incubated for 24 hours, and turned into a resistant one after 48 hours of incubation. Results: Among the tested antifungal drugs in this study, the highest rate of resistance was observed against ITR (28.5%) followed by VOR (26.4%), FLU (20.8%) and KET (1.5%). The trailing effect was induced in 27 isolates (14.0%) by VOR, in 26 isolates (13.5%) by ITR, in 24 isolates (12.4%) by FLU, and in 19 isolates (9.8%) by KET. Conclusions: The monitoring of antifungal susceptibilities of Candida species isolated from clinical sources is highly recommended for the efficient management of patients. Moreover, the trailing effect should be taken into consideration once the interpretation of the results is intended.
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Affiliation(s)
- Kamiar Zomorodian
- Basic Sciences in Infectious Diseases Research Center, Shiraz University of Medical Sciences, Shiraz, IR Iran
- Department of Medical Mycology and Parasitology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, IR Iran
| | - Azadeh Bandegani
- Student Research Committee, Shiraz University of Medical Sciences, Shiraz, IR Iran
| | - Hossein Mirhendi
- Department of Medical Mycology and Parasitology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, IR Iran
| | - Keyvan Pakshir
- Basic Sciences in Infectious Diseases Research Center, Shiraz University of Medical Sciences, Shiraz, IR Iran
- Department of Medical Mycology and Parasitology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, IR Iran
| | - Navvab Alinejhad
- Student Research Committee, Shiraz University of Medical Sciences, Shiraz, IR Iran
| | - Ali Poostforoush Fard
- Basic Sciences in Infectious Diseases Research Center, Shiraz University of Medical Sciences, Shiraz, IR Iran
- Corresponding author: Ali Poostforoush Fard, Basic Sciences in Infectious Diseases Research Center, Shiraz University of Medical Sciences, Shiraz, IR Iran. Tel: +98-7112305291, Fax: +98-7112305291, E-mail:
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Álvarez-Pérez S, de Vega C, Pozo MI, Lenaerts M, Van Assche A, Herrera CM, Jacquemyn H, Lievens B. Nectar yeasts of the Metschnikowia clade are highly susceptible to azole antifungals widely used in medicine and agriculture. FEMS Yeast Res 2015; 16:fov115. [PMID: 26703195 DOI: 10.1093/femsyr/fov115] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/20/2015] [Indexed: 11/14/2022] Open
Abstract
The widespread use of azole antifungals in medicine and agriculture and the resulting long-persistent residues could potentially affect beneficial fungi. However, there is very little information on the tolerance of non-target environmental fungi to azoles. In this study, we assessed the susceptibility of diverse plant- and insect-associated yeasts from the Metschnikowia clade, including several ecologically important species, to widely used medical and agricultural azoles (epoxiconazole, imazalil, ketoconazole and voriconazole). A total of 120 strains from six species were tested. Minimum inhibitory concentrations (MICs) were determined by the EUCAST broth microdilution procedure after some necessary modifications were made. The majority of species tested were highly susceptible to epoxiconazole, ketoconazole and voriconazole (>95% of strains showed MICs ≤ 0.125 mg l(-1)). Most strains were also very susceptible to imazalil, although MIC values were generally higher than for the other azoles. Furthermore, certain Metschnikowia reukaufii strains displayed a 'trailing' phenotype (i.e. showed reduced but persistent growth at antifungal concentrations above the MIC), but this characteristic was dependent on test conditions. It was concluded that exposure to azoles may pose a risk for ecologically relevant yeasts from the Metschnikowia clade, and thus could potentially impinge on the tripartite interaction linking these fungi with plants and their insect pollinators.
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Affiliation(s)
- Sergio Álvarez-Pérez
- Department of Animal Health, Faculty of Veterinary Medicine, Universidad Complutense de Madrid, E-28040 Madrid, Spain Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems (M2S), KU Leuven, Campus De Nayer, B-2860 Sint-Katelijne-Waver, Belgium
| | - Clara de Vega
- Estación Biológica de Doñana, CSIC, E-41092 Sevilla, Spain
| | - María I Pozo
- Plant Population and Conservation Biology, Biology Department, KU Leuven, B-3001 Heverlee, Belgium
| | - Marijke Lenaerts
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems (M2S), KU Leuven, Campus De Nayer, B-2860 Sint-Katelijne-Waver, Belgium
| | - Ado Van Assche
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems (M2S), KU Leuven, Campus De Nayer, B-2860 Sint-Katelijne-Waver, Belgium
| | | | - Hans Jacquemyn
- Plant Population and Conservation Biology, Biology Department, KU Leuven, B-3001 Heverlee, Belgium
| | - Bart Lievens
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems (M2S), KU Leuven, Campus De Nayer, B-2860 Sint-Katelijne-Waver, Belgium
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Mane A, Vidhate P, Kusro C, Waman V, Saxena V, Kulkarni-Kale U, Risbud A. Molecular mechanisms associated with Fluconazole resistance in clinical Candida albicans isolates from India. Mycoses 2015; 59:93-100. [PMID: 26648048 DOI: 10.1111/myc.12439] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 10/12/2015] [Accepted: 10/30/2015] [Indexed: 11/27/2022]
Abstract
Resistance to azole antifungals is a significant problem in Candida albicans. An understanding of resistance at molecular level is essential for the development of strategies to tackle resistance and rationale design of newer antifungals and target-based molecular approaches. This study presents the first evaluation of molecular mechanisms associated with fluconazole resistance in clinical C.albicans isolates from India. Target site (ERG11) alterations were determined by DNA sequencing, whereas real-time PCRs were performed to quantify target and efflux pump genes (CDR1, CDR2, MDR1) in 87 [Fluconazole susceptible (n = 30), susceptible-dose dependent (n = 30) and resistant (n = 27)] C.albicans isolates. Cross-resistance to fluconazole, ketoconazole and itraconazole was observed in 74.1% isolates. Six amino acid substitutions were identified, including 4 (E116D, F145L, E226D, I437V) previously reported ones and 2 (P406L, Q474H) new ones. CDR1 over-expression was seen in 77.7% resistant isolates. CDR2 was exclusively expressed with CDR1 and their concomitant over-expression was associated with azole cross-resistance. MDR1 and ERG11 over-expression did not seem to be associated with resistance. Our results show that drug efflux mediated by Adenosine-5'-triphosphate (ATP)-binding cassette transporters, especially CDR1 is the predominant mechanism of fluconazole resistance and azole cross-resistance in C. albicans and indicate the need for research directed towards developing strategies to tackle efflux mediated resistance to salvage azoles.
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Affiliation(s)
- Arati Mane
- National AIDS Research Institute, Pune, Maharashtra, India
| | | | - Chanchal Kusro
- National AIDS Research Institute, Pune, Maharashtra, India
| | - Vaishali Waman
- Savitribai Phule Pune University (Formerly University of Pune), Bioinformatics Centre, Pune, Maharashtra, India
| | - Vandana Saxena
- National AIDS Research Institute, Pune, Maharashtra, India
| | - Urmila Kulkarni-Kale
- Savitribai Phule Pune University (Formerly University of Pune), Bioinformatics Centre, Pune, Maharashtra, India
| | - Arun Risbud
- National AIDS Research Institute, Pune, Maharashtra, India
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Salari S, Khosravi AR, Mousavi SAA, Nikbakht-Brojeni GH. Mechanisms of resistance to fluconazole in Candida albicans clinical isolates from Iranian HIV-infected patients with oropharyngeal candidiasis. J Mycol Med 2015; 26:35-41. [PMID: 26627124 DOI: 10.1016/j.mycmed.2015.10.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Revised: 09/27/2015] [Accepted: 10/04/2015] [Indexed: 11/19/2022]
Abstract
OBJECTIVES The opportunistic pathogen Candida albicans is the major agent of oropharyngeal candidiasis (OPC) in HIV/AIDS patients. The increased use of fluconazole can lead to the emergence of azole-resistant strains and treatment failures in PLWH (people living with HIV) receiving long-term therapy for OPC. The purpose of this study was to evaluate CDR1, CDR2, MDR1, and ERG11 gene expression in C. albicans clinically isolated from HIV-infected patients in Iran. PATIENTS AND METHODS In this study, we evaluated the molecular mechanisms of azole resistance in 20 fluconazole-resistant C. albicans isolates obtained from Iranian HIV-infected patients with oropharyngeal candidiasis by Real-Time polymerase chain reaction. RESULTS The overexpression of drug efflux pump CDR1 gene was found to be the major resistance mechanism observed in these isolates. The overexpression of the CDR1 gene correlated strongly with increasing resistance to fluconazole (P<0.05). Additionally, an increased level of mRNA in ERG11 was not observed in any of the tested isolates. CONCLUSIONS Our findings suggested that the CDR1 gene expression to fluconazole resistance in C. albicans is greater than other known genes.
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Affiliation(s)
- S Salari
- Department of Medical Parasitology and Mycology, Kerman University of Medical Sciences, Kerman, Iran; Regional Knowledge Hub, and WHO Collaborating Centre for HIV Surveillance, Kerman University of Medical Sciences, Kerman, Iran.
| | - A R Khosravi
- Mycology Research Center, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - S A A Mousavi
- Department of Medical Parasitology and Mycology, Kerman University of Medical Sciences, Kerman, Iran
| | - G H Nikbakht-Brojeni
- Department of Microbiology and Immunology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
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Rosana Y, Yasmon A, Lestari DC. Overexpression and mutation as a genetic mechanism of fluconazole resistance in Candida albicans isolated from human immunodeficiency virus patients in Indonesia. J Med Microbiol 2015; 64:1046-1052. [PMID: 26297039 DOI: 10.1099/jmm.0.000123] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Fluconazole is the standard treatment for oropharyngeal candidiasis, which is the third most common opportunistic infection in human immunodeficiency virus (HIV)/AIDS patients in Indonesia. Overuse of this drug could lead to the emergence of resistance. The objective of this study was to analyse the role of ERG11, CDR1, CDR2 and MDR1 gene overexpression and mutations in the ERG11 gene as a genetic mechanism of fluconazole resistance in Candida albicans isolated from HIV patients in Indonesia. Overexpression of ERG11, CDR1, CDR2 and MDR1 was analysed by real-time reverse transcription PCR, while ERG11 gene mutation analysis was performed using sequencing methods. Seventeen isolates out of 92 strains of C. albicans isolated from 108 HIV patients were found to be resistant to azole antifungals. The highest gene overexpression of ERG11 was found in C. albicans resistant to single fluconazole, while the highest gene overexpression of CDR2 was detected in all isolates of C. albicans resistant to multiple azoles. Amino acid substitutions were observed at six positions, i.e. D116E, D153E, I261V, E266D, V437I and V488I. The amino acid substitution I261V was identified in this study and was probably associated with fluconazole resistance. The combination of overexpression of CDR2 and ERG11 and mutation in the ERG11 gene was found to be a genetic mechanism of fluconazole resistance in C. albicans isolated from HIV patients in Indonesia.
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Affiliation(s)
- Yeva Rosana
- Department of Microbiology, Faculty of Medicine, University of Indonesia, Jalan Pegangsaan Timur no. 16, Jakarta 10320, Indonesia
| | - Andi Yasmon
- Department of Microbiology, Faculty of Medicine, University of Indonesia, Jalan Pegangsaan Timur no. 16, Jakarta 10320, Indonesia
| | - Delly Chipta Lestari
- Department of Microbiology, Faculty of Medicine, University of Indonesia, Jalan Pegangsaan Timur no. 16, Jakarta 10320, Indonesia
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Jensen RH, Astvad KMT, Silva LV, Sanglard D, Jørgensen R, Nielsen KF, Mathiasen EG, Doroudian G, Perlin DS, Arendrup MC. Stepwise emergence of azole, echinocandin and amphotericin B multidrug resistance in vivo in Candida albicans orchestrated by multiple genetic alterations. J Antimicrob Chemother 2015; 70:2551-5. [PMID: 26017038 DOI: 10.1093/jac/dkv140] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 04/24/2015] [Indexed: 01/06/2023] Open
Abstract
OBJECTIVES The objective of this study was to characterize the underlying molecular mechanisms in consecutive clinical Candida albicans isolates from a single patient displaying stepwise-acquired multidrug resistance. METHODS Nine clinical isolates (P-1 to P-9) were susceptibility tested by EUCAST EDef 7.2 and Etest. P-4, P-5, P-7, P-8 and P-9 were available for further studies. Relatedness was evaluated by MLST. Additional genes were analysed by sequencing (including FKS1, ERG11, ERG2 and TAC1) and gene expression by quantitative PCR (CDR1, CDR2 and ERG11). UV-spectrophotometry and GC-MS were used for sterol analyses. In vivo virulence was determined in the insect model Galleria mellonella and evaluated by log-rank Mantel-Cox tests. RESULTS P-1 + P-2 were susceptible, P-3 + P-4 fluconazole resistant, P-5 pan-azole resistant, P-6 + P-7 pan-azole and echinocandin resistant and P-8 + P-9 MDR. MLST supported genetic relatedness among clinical isolates. P-4 harboured four changes in Erg11 (E266D, G307S, G450E and V488I), increased expression of ERG11 and CDR2 and a change in Tac1 (R688Q). P-5, P-7, P-8 and P-9 had an additional change in Erg11 (A61E), increased expression of CDR1, CDR2 and ERG11 (except for P-7) and a different amino acid change in Tac1 (R673L). Echinocandin-resistant isolates harboured the Fks1 S645P alteration. Polyene-resistant P-8 + P-9 lacked ergosterol and harboured a frameshift mutation in ERG2 (F105SfsX23). Virulence was attenuated (but equivalent) in the clinical isolates, but higher than in the azole- and echinocandin-resistant unrelated control strain. CONCLUSIONS C. albicans demonstrates a diverse capacity to adapt to antifungal exposure. Potentially novel resistance-inducing mutations in TAC1, ERG11 and ERG2 require independent validation.
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Affiliation(s)
- Rasmus Hare Jensen
- Microbiology and Infection Control, Statens Serum Institut, Copenhagen, Denmark
| | | | - Luis Vale Silva
- Institute of Microbiology, University of Lausanne and University Hospital Center (CHUV), Lausanne, Switzerland
| | - Dominique Sanglard
- Institute of Microbiology, University of Lausanne and University Hospital Center (CHUV), Lausanne, Switzerland
| | - Rene Jørgensen
- Microbiology and Infection Control, Statens Serum Institut, Copenhagen, Denmark
| | - Kristian Fog Nielsen
- Department of Systems Biology, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Estella Glintborg Mathiasen
- Microbiology and Infection Control, Statens Serum Institut, Copenhagen, Denmark Department of Systems Biology, Technical University of Denmark, Kgs. Lyngby, Denmark
| | | | - David Scott Perlin
- Public Health and Research Institute, New Jersey Medical School-Rutgers Biomedical and Health Sciences, Newark, NJ, USA
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Li X, Cai Q, Mei H, Zhou X, Shen Y, Li D, Liu W. The Rpd3/Hda1 family of histone deacetylases regulates azole resistance in Candida albicans. J Antimicrob Chemother 2015; 70:1993-2003. [DOI: 10.1093/jac/dkv070] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Accepted: 02/23/2015] [Indexed: 12/25/2022] Open
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Khan MA, Aljarbou AN, Khan A, Younus H. Liposomal thymoquinone effectively combats fluconazole-resistant Candida albicans in a murine model. Int J Biol Macromol 2015; 76:203-8. [PMID: 25709021 DOI: 10.1016/j.ijbiomac.2015.02.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 02/04/2015] [Accepted: 02/08/2015] [Indexed: 01/10/2023]
Abstract
The aim of the present study was to develop a novel liposomal formulation of thymoquinone (TQ) to treat fluconazole-susceptible and -resistant Candida albicans (C. albicans) infections. The liposomal preparation of TQ (Lip-TQ) was used against a fluconazole-susceptible or -resistant isolate of C. albicans. Various doses of fluconazole (0, 5, 10, 20 and 40 mg/kg) or free TQ or Lip-TQ (0, 1, 2 and 5mg/kg) were used to treat C. albicans infected mice. Mice were observed for 40 days post C. albicans infection, and their kidneys were assessed for the fungal load. Fluconazole showed anti-fungal activity against the drug-susceptible, but not against the -resistant isolate of C. albicans. Free TQ showed its activity against both fluconazole-susceptible or -resistant C. albicans, however, Lip-TQ was found to be the most effective and imparted ∼ 100% and ∼ 90% survival of mice infected with fluconazole-susceptible and -resistant isolates of C. albicans, respectively. Mice treated with Lip-TQ showed highly reduced severity of infection in their tissue homogenates. Therefore, Lip-TQ may effectively be used in the treatment of C. albicans infections, including those which are not responding to fluconazole.
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Affiliation(s)
- Masood Alam Khan
- Department of Basic Health Sciences, College of Applied Medical Sciences, Qassim University, Buraidah 51452, Saudi Arabia
| | - Ahmad N Aljarbou
- Department of Pharmaceutics, College of Pharmacy, Qassim University, Buraidah 51452, Saudi Arabia
| | - Arif Khan
- Department of Basic Health Sciences, College of Applied Medical Sciences, Qassim University, Buraidah 51452, Saudi Arabia
| | - Hina Younus
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002, India.
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The widely used ATB FUNGUS 3 automated readings in China and its misleading high MICs of Candida spp. to azoles: challenges for developing countries' clinical microbiology labs. PLoS One 2014; 9:e114004. [PMID: 25460351 PMCID: PMC4252076 DOI: 10.1371/journal.pone.0114004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 11/03/2014] [Indexed: 11/19/2022] Open
Abstract
The rapid development in the clinical microbiology diagnostic assays presents more challenges for developing countries than for the developed world, especially in the area of test validation before the introduction of new tests. Here we report on the misleading high MICs of Candida spp. to azoles using the ATB FUNGUS 3 (bioMérieux, La Balme-les Grottes, France) with automated readings in China to highlight the dangers of introducing a diagnostic assay without validation. ATB FUNGUS 3 is the most commonly used commercial antifungal susceptibility testing method in China. An in-depth analysis of data showed higher levels of resistance to azoles when ATB FUNGUS 3 strips were read automatically than when read visually. Based on this finding, the performance of ATB FUNGUS 3, read both visually and automatically, was evaluated by testing 218 isolates of five clinically important Candida species, using broth microdilution (BMD) following CLSI M27-A3 as the gold-standard. The overall essential agreement (EA) between ATB visual readings and BMD was 99.1%. In contrast, the ATB automated readings showed higher discrepancies with BMD, with overall EA of 86.2%, and specifically lower EA was observed for fluconazole (80.7%), voriconazole (77.5%), and itraconazole (73.4%), which was most likely due to the trailing effect of azoles. The major errors in azole drug susceptibilities by ATB automated readings is a concern in China that can result in misleading clinical antifungal drug selection and pseudo high rates of antifungal resistance. Therefore, the ATB visual reading is generally recommended. In the meantime, we propose a practical algorithm to be followed for ATB FUNGUS 3 antifungal susceptibility for Candida spp. before the improvement in the automated reading system.
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Contribution of clinically derived mutations in ERG11 to azole resistance in Candida albicans. Antimicrob Agents Chemother 2014; 59:450-60. [PMID: 25385095 DOI: 10.1128/aac.03470-14] [Citation(s) in RCA: 175] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In Candida albicans, the ERG11 gene encodes lanosterol demethylase, the target of the azole antifungals. Mutations in ERG11 that result in an amino acid substitution alter the abilities of the azoles to bind to and inhibit Erg11, resulting in resistance. Although ERG11 mutations have been observed in clinical isolates, the specific contributions of individual ERG11 mutations to azole resistance in C. albicans have not been widely explored. We sequenced ERG11 in 63 fluconazole (FLC)-resistant clinical isolates. Fifty-five isolates carried at least one mutation in ERG11, and we observed 26 distinct positions in which amino acid substitutions occurred. We mapped the 26 distinct variant positions in these alleles to four regions in the predicted structure for Erg11, including its predicted catalytic site, extended fungus-specific external loop, proximal surface, and proximal surface-to-heme region. In total, 31 distinct ERG11 alleles were recovered, with 10 ERG11 alleles containing a single amino acid substitution. We then characterized 19 distinct ERG11 alleles by introducing them into the wild-type azole-susceptible C. albicans SC5314 strain and testing them for susceptibilities to FLC, itraconazole (ITC), and voriconazole (VRC). The strains that were homozygous for the single amino acid substitutions Y132F, K143R, F145L, S405F, D446E, G448E, F449V, G450E, and G464S had a ≥ 4-fold increase in FLC MIC. The strains that were homozygous for several double amino acid substitutions had decreased azole susceptibilities beyond those conferred by any single amino acid substitution. These findings indicate that mutations in ERG11 are prevalent among azole-resistant clinical isolates and that most mutations result in appreciable changes in FLC and VRC susceptibilities.
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Reduced susceptibility of Candida albicans clinical isolates to azoles and detection of mutations in the ERG11 gene. Diagn Microbiol Infect Dis 2013; 77:327-9. [DOI: 10.1016/j.diagmicrobio.2013.08.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 08/20/2013] [Accepted: 08/23/2013] [Indexed: 11/24/2022]
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Yang YL, Chen HT, Lin CC, Chu WL, Lo HJ. Species distribution and drug susceptibilities of Candida isolates in TSARY 2010. Diagn Microbiol Infect Dis 2013; 76:182-6. [PMID: 23574935 DOI: 10.1016/j.diagmicrobio.2013.03.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 03/06/2013] [Accepted: 03/06/2013] [Indexed: 11/24/2022]
Abstract
Susceptibilities to antifungal drugs of 1083 Candida isolates collected in Taiwan Surveillance of Antimicrobial Resistance of Yeasts in 2010 were determined. There were 422 (39%) C. albicans, 270 (24.9%) C. tropicalis, 258 (23.8%) C. glabrata, 87 (8%) C. parapsilosis, 18 (1.7%) C. krusei, and 28 (2.6%) of 13 other species. In the present study, we have applied species-specific clinical breakpoints for common species and epidemiological cutoff values for rare species. We found that majority of isolates were susceptible to tested drugs. A total of 15, 3, 2, and 0 isolates were not susceptible to fluconazole, voriconazole, amphotericin B, and anidulafungin, respectively. We found that three of the four fluconazole non-susceptible C. albicans isolates were resistant to voriconazole. Hence, there is an issue of cross-resistance among azole-type drugs.
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Affiliation(s)
- Yun-Liang Yang
- Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan, ROC
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Yang YL, Lin CC, Chang TP, Lauderdale TL, Chen HT, Lee CF, Hsieh CW, Chen PC, Lo HJ. Comparison of human and soil Candida tropicalis isolates with reduced susceptibility to fluconazole. PLoS One 2012; 7:e34609. [PMID: 22496832 PMCID: PMC3320620 DOI: 10.1371/journal.pone.0034609] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2011] [Accepted: 03/06/2012] [Indexed: 01/19/2023] Open
Abstract
Infections caused by treatment-resistant non-albicans Candida species, such as C. tropicalis, has increased, which is an emerging challenge in the management of fungal infections. Genetically related diploid sequence type (DST) strains of C. tropicalis exhibiting reduced susceptibility to fluconazole circulated widely in Taiwan. To identify the potential source of these wildly distributed DST strains, we investigated the possibility of the presence in soil of such C. tropicalis strains by pulsed field gel electrophoresis (PFGE) and DST typing methods. A total of 56 C. tropicalis isolates were recovered from 26 out of 477 soil samples. Among the 18 isolates with reduced susceptibility to fluconazole, 9 belonged to DST149 and 3 belonged to DST140. Both DSTs have been recovered from our previous studies on clinical isolates from the Taiwan Surveillance of Antimicrobial Resistance of Yeasts (TSARY) program. Furthermore, these isolates were more resistant to agricultural azoles. We have found genetically related C. tropicalis exhibiting reduced susceptibility to fluconazole from the human hosts and environmental samples. Therefore, to prevent patients from acquiring C. tropicalis with reduced susceptibility to azoles, prudent use of azoles in both clinical and agricultural settings is advocated.
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Affiliation(s)
- Yun-Liang Yang
- Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan
- Institute of Molecular Medicine and Bioengineering, National Chiao Tung University, Hsinchu, Taiwan
| | - Chih-Chao Lin
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli, Taiwan
| | - Te-Pin Chang
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli, Taiwan
| | - Tsai-Ling Lauderdale
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli, Taiwan
| | - Hui-Ting Chen
- Institute of Molecular Medicine and Bioengineering, National Chiao Tung University, Hsinchu, Taiwan
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli, Taiwan
| | - Ching-Fu Lee
- Department of Applied Science, National Hsinchu University of Education, Hsinchu, Taiwan
| | - Chih-Wen Hsieh
- Department of Applied Science, National Hsinchu University of Education, Hsinchu, Taiwan
| | - Pei-Chen Chen
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli, Taiwan
| | - Hsiu-Jung Lo
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli, Taiwan
- School of Dentistry, China of Medical University, Taichung, Taiwan
- * E-mail:
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Dornelas-Ribeiro M, Pinheiro EO, Guerra C, Braga-Silva LA, Carvalho SMFD, Santos ALSD, Rozental S, Fracalanzza SEL. Cellular characterisation of Candida tropicalis presenting fluconazole-related trailing growth. Mem Inst Oswaldo Cruz 2012; 107:31-8. [DOI: 10.1590/s0074-02762012000100005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Accepted: 08/16/2011] [Indexed: 11/22/2022] Open
Affiliation(s)
- Marcos Dornelas-Ribeiro
- Instituto de Biologia do Exército, Brasil; Instituto Estadual de Hematologia, Brasil; Hospital Adventista Silvestre, Brasil; Instituto de Microbiologia Paulo de Góes
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Alvarez-Rueda N, Fleury A, Morio F, Pagniez F, Gastinel L, Le Pape P. Amino acid substitutions at the major insertion loop of Candida albicans sterol 14alpha-demethylase are involved in fluconazole resistance. PLoS One 2011; 6:e21239. [PMID: 21698128 PMCID: PMC3116904 DOI: 10.1371/journal.pone.0021239] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Accepted: 05/24/2011] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND In the fungal pathogen Candida albicans, amino acid substitutions of 14alpha-demethylase (CaErg11p, CaCYP51) are associated with azole antifungals resistance. This is an area of research which is very dynamic, since the stakes concern the screening of new antifungals which circumvent resistance. The impact of amino acid substitutions on azole interaction has been postulated by homology modeling in comparison to the crystal structure of Mycobacterium tuberculosis (MT-CYP51). Modeling of amino acid residues situated between positions 428 to 459 remains difficult to explain to date, because they are in a major insertion loop specifically present in fungal species. METHODOLOGY/PRINCIPAL FINDING Fluconazole resistance of clinical isolates displaying Y447H and V456I novel CaErg11p substitutions confirmed in vivo in a murine model of disseminated candidiasis. Y447H and V456I implication into fluconazole resistance was then studied by site-directed mutagenesis of wild-type CaErg11p and by heterogeneously expression into the Pichia pastoris model. CLSI modified tests showed that V447H and V456I are responsible for an 8-fold increase in fluconazole MICs of P. pastoris mutants compared to the wild-type controls. Moreover, mutants showed a sustained capacity for producing ergosterol, even in the presence of fluconazole. Based on these biological results, we are the first to propose a hybrid homology structure-function model of Ca-CYP51 using 3 different homology modeling programs. The variable position of the protein insertion loop, using different liganded or non-liganded templates of recently solved CYP51 structures, suggests its inherent flexibility. Mapping of recognized azole-resistant substitutions indicated that the flexibility of this region is probably enhanced by the relatively high glycine content of the consensus. CONCLUSIONS/SIGNIFICANCE The results highlight the potential role of the insertion loop in azole resistance in the human pathogen C. albicans. This new data should be taken into consideration for future studies aimed at designing new antifungal agents, which circumvent azole resistance.
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Affiliation(s)
- Nidia Alvarez-Rueda
- Département de Parasitologie et de Mycologie Médicale, Université de Nantes, Nantes Atlantique Universités, EA1155 – IICiMed, Faculté de Pharmacie de Nantes, Nantes, France
- * E-mail: (PLP); (NAR)
| | - Audrey Fleury
- Département de Parasitologie et de Mycologie Médicale, Université de Nantes, Nantes Atlantique Universités, EA1155 – IICiMed, Faculté de Pharmacie de Nantes, Nantes, France
| | - Florent Morio
- Département de Parasitologie et de Mycologie Médicale, Université de Nantes, Nantes Atlantique Universités, EA1155 – IICiMed, Faculté de Pharmacie de Nantes, Nantes, France
- Laboratoire de Parasitologie-Mycologie, CHU de Nantes, Nantes, France
| | - Fabrice Pagniez
- Département de Parasitologie et de Mycologie Médicale, Université de Nantes, Nantes Atlantique Universités, EA1155 – IICiMed, Faculté de Pharmacie de Nantes, Nantes, France
| | - Louis Gastinel
- Laboratoire de Pharmacologie des Immunosuppresseurs en Transplantation, INSERM UMR 850, Université de Limoges, Limoges, France
| | - Patrice Le Pape
- Département de Parasitologie et de Mycologie Médicale, Université de Nantes, Nantes Atlantique Universités, EA1155 – IICiMed, Faculté de Pharmacie de Nantes, Nantes, France
- Laboratoire de Parasitologie-Mycologie, CHU de Nantes, Nantes, France
- * E-mail: (PLP); (NAR)
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Borecká S, Pinjon E, Sullivan DJ, Kuchler K, Blaško J, Kulková N, Bujdáková H. Cdr2p contributes to fluconazole resistance in Candida dubliniensis clinical isolates. Can J Microbiol 2011; 57:416-26. [PMID: 21542785 DOI: 10.1139/w11-025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
The development of resistance to azole antifungals used in the treatment of fungal infections can be a serious medical problem. Here, we investigate the molecular mechanisms associated with reduced susceptibility to fluconazole in clinical isolates of Candida dubliniensis , showing evidence of the trailing growth phenomenon. The changes in membrane sterol composition were studied in the presence of subinhibitory fluconazole concentrations. Despite lanosterol and eburicol accumulating as the most prevalent sterols after fluconazole treatment, these ergosterol precursors still support growth of Candida isolates. The overexpression of ABC transporters was demonstrated by immunoblotting employing specific antibodies against Cdr1p and Cdr2p. The presence of a full-length 170 kDa protein Cdr1p was detected in two isolates, while a truncated form of Cdr1p with the molecular mass of 85 kDa was observed in isolate 966/3(2). Notably, Cdr2p was detected in this isolate, and the expression of this transporter was modulated by subinhibitory concentrations of fluconazole. These results suggest that C. dubliniensis can display the trailing growth phenomenon, and such isolates express similar molecular mechanisms like that of fluconazole-resistant isolates and can therefore be associated with recurrent infections.
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Affiliation(s)
- Silvia Borecká
- Comenius University in Bratislava, Department of Microbiology and Virology, Mlynská dolina, Bratislava, Slovak Republic
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Characterization of Candida Species from Different Populations in Taiwan. Mycopathologia 2011; 172:131-9. [DOI: 10.1007/s11046-011-9408-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Accepted: 02/17/2011] [Indexed: 10/18/2022]
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Chromogenic Medium for Direct Susceptibility Testing of Candida spp. Isolated from Urine. Mycopathologia 2011; 172:125-30. [DOI: 10.1007/s11046-011-9407-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Accepted: 02/16/2011] [Indexed: 10/18/2022]
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Yang YL, Cheng MF, Wang CW, Wang AH, Cheng WT, Lo HJ, Hospitals T. The distribution of species and susceptibility of amphotericin B and fluconazole of yeast pathogens isolated from sterile sites in Taiwan. Med Mycol 2010; 48:328-34. [PMID: 20141372 DOI: 10.3109/13693780903154070] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
To study the demographic changes of yeasts causing invasive infections in Taiwan, especially with respect to species distribution and antifungal susceptibility, we analyzed isolates obtained from four sterile sites of patients in 19 hospitals in 2002 (155 strains) and again from the same hospitals in 2006 (208 strains). Blood was the most common source of the yeasts, accounting for 73.8% of the total isolates, followed by ascites (21.5%), cerebrospinal fluid (3%), and synovia (1.7%). Candida albicans was the most frequently recovered species (50.1% of the total), followed by Candida tropicalis (20.7%), Candida glabrata (11.6%), Candida parapsilosis (8.5%), Cryptococcus neoformans (3.9%), Candida krusei (0.8%), and nine other species (4.3%). There were one (0.3%) and seven (1.9%) isolates with minimum inhibitory concentrations (MICs) of amphotericin B > or =2 mg/l after 24 h and 48 h incubation, respectively. In addition, there were 15 (4.3%) and 31 (8.6%) isolates with MICs of fluconazole > or =64 mg/l under the same conditions. The MIC(90) value of amphotericin B was 1 mg/l. The MIC(90) values of fluconazole were 4 mg/l after 24 h incubation and 32 mg/l after 48 h incubation. Interestingly, MICs for fluconazole > or =64 mg/l after 24 h were significantly higher for isolates obtained in 2006 than those in 2002 after 24 h (7.1% vs. 0.7%, p =0.009) and 48 h (13.5% vs. 2%, p =0.0003) incubations. The demographic difference between these two surveys is mainly due to one species, C. tropicalis.
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Affiliation(s)
- Y L Yang
- Department of Biological Science and Technology, Institute of Molecular Medicine and Bioengineering, National Chiao Tung University, Hsinchu, Taiwan
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