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Spruijtenburg B, Baqueiro CCSZ, Colombo AL, Meijer EFJ, de Almeida JN, Berrio I, Fernández NB, Chaves GM, Meis JF, de Groot T. Short Tandem Repeat Genotyping and Antifungal Susceptibility Testing of Latin American Candida tropicalis Isolates. J Fungi (Basel) 2023; 9:jof9020207. [PMID: 36836321 PMCID: PMC9958743 DOI: 10.3390/jof9020207] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 01/31/2023] [Accepted: 02/03/2023] [Indexed: 02/08/2023] Open
Abstract
Candida tropicalis is emerging as one of the most common Candida species causing opportunistic infections in Latin America. Outbreak events caused by C. tropicalis were reported, and antifungal resistant isolates are on the rise. In order to investigate population genomics and look into antifungal resistance, we applied a short tandem repeat (STR) genotyping scheme and antifungal susceptibility testing (AFST) to 230 clinical and environmental C. tropicalis isolates from Latin American countries. STR genotyping identified 164 genotypes, including 11 clusters comprised of three to seven isolates, indicating outbreak events. AFST identified one isolate as anidulafungin-resistant and harboring a FKS1 S659P substitution. Moreover, we identified 24 clinical and environmental isolates with intermediate susceptibility or resistance to one or more azoles. ERG11 sequencing revealed each of these isolates harboring a Y132F and/or Y257H/N substitution. All of these isolates, except one, were clustered together in two groups of closely related STR genotypes, with each group harboring distinct ERG11 substitutions. The ancestral C. tropicalis strain of these isolates likely acquired the azole resistance-associated substitutions and subsequently spread across vast distances within Brazil. Altogether, this STR genotyping scheme for C. tropicalis proved to be useful for identifying unrecognized outbreak events and better understanding population genomics, including the spread of antifungal-resistant isolates.
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Affiliation(s)
- Bram Spruijtenburg
- Department of Medical Microbiology and Infectious Diseases, Canisius-Wilhelmina Hospital, 6532 SZ Nijmegen, The Netherlands
- Center of Expertise in Mycology, Radboud University Medical Center, Canisius-Wilhelmina Hospital, 6532 SZ Nijmegen, The Netherlands
| | - Cynthea C. S. Z. Baqueiro
- Disciplina de Infectologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo 04021-001, SP, Brazil
| | - Arnaldo L. Colombo
- Disciplina de Infectologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo 04021-001, SP, Brazil
| | - Eelco F. J. Meijer
- Department of Medical Microbiology and Infectious Diseases, Canisius-Wilhelmina Hospital, 6532 SZ Nijmegen, The Netherlands
- Center of Expertise in Mycology, Radboud University Medical Center, Canisius-Wilhelmina Hospital, 6532 SZ Nijmegen, The Netherlands
| | - João N. de Almeida
- Disciplina de Infectologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo 04021-001, SP, Brazil
- Hospital Israelita Albert Einstein, São Paulo 05652-900, SP, Brazil
| | - Indira Berrio
- Hospital General de Medellín Luz Castro de Gutiérrez ESE, Medellín 050015, Colombia
- Medical and Experimental Mycology Group, Corporación para Investigaciones Biológicas (CIB), Medellín 050015, Colombia
| | - Norma B. Fernández
- Hospital de Clínicas, Universidad de Buenos Aires, Buenos Aires 2351, Argentina
| | - Guilherme M. Chaves
- Departamento de Análises Clínicas e Toxicológicas, Universidade Federal do Rio Grande do Norte, Natal 59078-970, RN, Brazil
| | - Jacques F. Meis
- Department of Medical Microbiology and Infectious Diseases, Canisius-Wilhelmina Hospital, 6532 SZ Nijmegen, The Netherlands
- Center of Expertise in Mycology, Radboud University Medical Center, Canisius-Wilhelmina Hospital, 6532 SZ Nijmegen, The Netherlands
- Bioprocess Engineering and Biotechnology Graduate Program, Federal University of Paraná, Curitiba 80060-000, PR, Brazil
- Department I of Internal Medicine, University of Cologne, Faculty of Medicine and University Hospital Cologne, Excellence Center for Medical Mycology, 50931 Cologne, Germany
| | - Theun de Groot
- Department of Medical Microbiology and Infectious Diseases, Canisius-Wilhelmina Hospital, 6532 SZ Nijmegen, The Netherlands
- Center of Expertise in Mycology, Radboud University Medical Center, Canisius-Wilhelmina Hospital, 6532 SZ Nijmegen, The Netherlands
- Correspondence:
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Lima R, Ribeiro FC, Colombo AL, de Almeida JN. The emerging threat antifungal-resistant Candida tropicalis in humans, animals, and environment. FRONTIERS IN FUNGAL BIOLOGY 2022; 3:957021. [PMID: 37746212 PMCID: PMC10512401 DOI: 10.3389/ffunb.2022.957021] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 07/28/2022] [Indexed: 09/26/2023]
Abstract
Antifungal resistance in humans, animals, and the environment is an emerging problem. Among the different fungal species that can develop resistance, Candida tropicalis is ubiquitous and causes infections in animals and humans. In Asia and some Latin American countries, C. tropicalis is among the most common species related to candidemia, and mortality rates are usually above 40%. Fluconazole resistance is especially reported in Asian countries and clonal spread in humans and the environment has been investigated in some studies. In Brazil, high rates of azole resistance have been found in animals and the environment. Multidrug resistance is still rare, but recent reports of clinical multidrug-resistant isolates are worrisome. The molecular apparatus of antifungal resistance has been majorly investigated in clinical C. tropicalis isolates, revealing that this species can develop resistance through the conjunction of different adaptative mechanisms. In this review article, we summarize the main findings regarding antifungal resistance and Candida tropicalis through an "One Health" approach.
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Affiliation(s)
- Ricardo Lima
- Special Mycology Laboratory, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Felipe C. Ribeiro
- Special Mycology Laboratory, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Arnaldo L. Colombo
- Special Mycology Laboratory, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Joăo N. de Almeida
- Special Mycology Laboratory, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
- Clinical Laboratory, Hospital Israelita Albert Einstein, São Paulo, Brazil
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Wang Y, Fan X, Wang H, Kudinha T, Mei YN, Ni F, Pan YH, Gao LM, Xu H, Kong HS, Yang Q, Wang WP, Xi HY, Luo YP, Ye LY, Xiao M. Continual Decline in Azole Susceptibility Rates in Candida tropicalis Over a 9-Year Period in China. Front Microbiol 2021; 12:702839. [PMID: 34305872 PMCID: PMC8299486 DOI: 10.3389/fmicb.2021.702839] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/09/2021] [Indexed: 11/13/2022] Open
Abstract
Background There have been reports of increasing azole resistance in Candida tropicalis, especially in the Asia-Pacific region. Here we report on the epidemiology and antifungal susceptibility of C. tropicalis causing invasive candidiasis in China, from a 9-year surveillance study. Methods From August 2009 to July 2018, C. tropicalis isolates (n = 3702) were collected from 87 hospitals across China. Species identification was carried out by mass spectrometry or rDNA sequencing. Antifungal susceptibility was determined by Clinical and Laboratory Standards Institute disk diffusion (CHIF-NET10-14, n = 1510) or Sensititre YeastOne (CHIF-NET15-18, n = 2192) methods. Results Overall, 22.2% (823/3702) of the isolates were resistant to fluconazole, with 90.4% (744/823) being cross-resistant to voriconazole. In addition, 16.9 (370/2192) and 71.7% (1572/2192) of the isolates were of non-wild-type phenotype to itraconazole and posaconazole, respectively. Over the 9 years of surveillance, the fluconazole resistance rate continued to increase, rising from 5.7 (7/122) to 31.8% (236/741), while that for voriconazole was almost the same, rising from 5.7 (7/122) to 29.1% (216/741), with no significant statistical differences across the geographic regions. However, significant difference in fluconazole resistance rate was noted between isolates cultured from blood (27.2%, 489/1799) and those from non-blood (17.6%, 334/1903) specimens (P-value < 0.05), and amongst isolates collected from medical wards (28.1%, 312/1110) versus intensive care units (19.6%, 214/1092) and surgical wards (17.9%, 194/1086) (Bonferroni adjusted P-value < 0.05). Although echinocandin resistance remained low (0.8%, 18/2192) during the surveillance period, it was observed in most administrative regions, and one-third (6/18) of these isolates were simultaneously resistant to fluconazole. Conclusion The continual decrease in the rate of azole susceptibility among C. tropicalis strains has become a nationwide challenge in China, and the emergence of multi-drug resistance could pose further threats. These phenomena call for effective efforts in future interventions.
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Affiliation(s)
- Yao Wang
- Department of Laboratory Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China.,Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China.,State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
| | - Xin Fan
- Department of Infectious Diseases and Clinical Microbiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - He Wang
- State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
| | - Timothy Kudinha
- School of Biomedical Sciences, Charles Sturt University, Orange, NSW, Australia.,New South Wales Health Pathology, Regional and Rural, Orange Hospital, Orange, NSW, Australia
| | - Ya-Ning Mei
- Department of Clinical Laboratory, Jiangsu Province Hospital, Nanjing, Jiangsu, China
| | - Fang Ni
- Department of Clinical Laboratory, Jiangsu Province Hospital, Nanjing, Jiangsu, China
| | - Yu-Hong Pan
- Department of Clinical Laboratory, Fujian Medical University Union Hospital, Fuzhou, China
| | - Lan-Mei Gao
- Department of Clinical Laboratory, Fujian Medical University Union Hospital, Fuzhou, China
| | - Hui Xu
- Department of Clinical Laboratory, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Hai-Shen Kong
- Department of Laboratory Medicine, First Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Qing Yang
- Department of Laboratory Medicine, First Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Wei-Ping Wang
- Institute of Laboratory Medicine, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Hai-Yan Xi
- Institute of Laboratory Medicine, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Yan-Ping Luo
- Medical Laboratory Center, Chinese PLA General Hospital, Medical School of Chinese PLA, Beijing, China
| | - Li-Yan Ye
- Medical Laboratory Center, Chinese PLA General Hospital, Medical School of Chinese PLA, Beijing, China
| | - Meng Xiao
- Department of Laboratory Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China.,Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China.,State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
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Arastehfar A, Lass-Flörl C, Garcia-Rubio R, Daneshnia F, Ilkit M, Boekhout T, Gabaldon T, Perlin DS. The Quiet and Underappreciated Rise of Drug-Resistant Invasive Fungal Pathogens. J Fungi (Basel) 2020; 6:E138. [PMID: 32824785 PMCID: PMC7557958 DOI: 10.3390/jof6030138] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 07/22/2020] [Accepted: 08/11/2020] [Indexed: 12/13/2022] Open
Abstract
Human fungal pathogens are attributable to a significant economic burden and mortality worldwide. Antifungal treatments, although limited in number, play a pivotal role in decreasing mortality and morbidities posed by invasive fungal infections (IFIs). However, the recent emergence of multidrug-resistant Candida auris and Candida glabrata and acquiring invasive infections due to azole-resistant C. parapsilosis, C. tropicalis, and Aspergillus spp. in azole-naïve patients pose a serious health threat considering the limited number of systemic antifungals available to treat IFIs. Although advancing for major fungal pathogens, the understanding of fungal attributes contributing to antifungal resistance is just emerging for several clinically important MDR fungal pathogens. Further complicating the matter are the distinct differences in antifungal resistance mechanisms among various fungal species in which one or more mechanisms may contribute to the resistance phenotype. In this review, we attempt to summarize the burden of antifungal resistance for selected non-albicansCandida and clinically important Aspergillus species together with their phylogenetic placement on the tree of life. Moreover, we highlight the different molecular mechanisms between antifungal tolerance and resistance, and comprehensively discuss the molecular mechanisms of antifungal resistance in a species level.
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Affiliation(s)
- Amir Arastehfar
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ 07110, USA;
| | - Cornelia Lass-Flörl
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, 6020 Innsbruck, Austria;
| | - Rocio Garcia-Rubio
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ 07110, USA;
| | - Farnaz Daneshnia
- Westerdijk Fungal Biodiversity Institute, 3584 CT Utrecht, The Netherlands; (F.D.); (T.B.)
| | - Macit Ilkit
- Division of Mycology, University of Çukurova, 01330 Adana, Turkey;
| | - Teun Boekhout
- Westerdijk Fungal Biodiversity Institute, 3584 CT Utrecht, The Netherlands; (F.D.); (T.B.)
- Institute of Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, 1012 WX Amsterdam, The Netherlands
| | - Toni Gabaldon
- Life Sciences Programme, Barcelona, Supercomputing Center (BSC-CNS), Jordi Girona, 08034 Barcelona, Spain;
- Mechanisms of Disease Programme, Institute for Research in Biomedicine (IRB), 08024 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain
| | - David S. Perlin
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ 07110, USA;
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Oliveira JSD, Pereira VS, Castelo-Branco DDSCM, Cordeiro RDA, Sidrim JJC, Brilhante RSN, Rocha MFG. The yeast, the antifungal, and the wardrobe: a journey into antifungal resistance mechanisms of Candida tropicalis. Can J Microbiol 2020; 66:377-388. [PMID: 32319304 DOI: 10.1139/cjm-2019-0531] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Candida tropicalis is a prominent non-Candida albicans Candida species involved in cases of candidemia, mainly causing infections in patients in intensive care units and (or) those presenting neutropenia. In recent years, several studies have reported an increase in the recovery rates of azole-resistant C. tropicalis isolates. Understanding C. tropicalis resistance is of great importance, since resistant strains are implicated in persistent or recurrent and breakthrough infections. In this review, we address the main mechanisms underlying C. tropicalis resistance to the major antifungal classes used to treat candidiasis. The main genetic basis involved in C. tropicalis antifungal resistance is discussed. A better understanding of the epidemiology of resistant strains and the mechanisms involved in C. tropicalis resistance can help improve diagnosis and assessment of the antifungal susceptibility of this Candida species to improve clinical management.
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Affiliation(s)
- Jonathas Sales de Oliveira
- Department of Pathology and Legal Medicine, School of Medicine, Specialized Medical Mycology Center, Graduate Program in Medical Microbiology, Federal University of Ceará, Fortaleza-CE, Brazil
| | - Vandbergue Santos Pereira
- Department of Pathology and Legal Medicine, School of Medicine, Specialized Medical Mycology Center, Graduate Program in Medical Microbiology, Federal University of Ceará, Fortaleza-CE, Brazil
| | - Débora de Souza Collares Maia Castelo-Branco
- Department of Pathology and Legal Medicine, School of Medicine, Specialized Medical Mycology Center, Graduate Program in Medical Microbiology, Federal University of Ceará, Fortaleza-CE, Brazil
| | - Rossana de Aguiar Cordeiro
- Department of Pathology and Legal Medicine, School of Medicine, Specialized Medical Mycology Center, Graduate Program in Medical Microbiology, Federal University of Ceará, Fortaleza-CE, Brazil
| | - José Júlio Costa Sidrim
- Department of Pathology and Legal Medicine, School of Medicine, Specialized Medical Mycology Center, Graduate Program in Medical Microbiology, Federal University of Ceará, Fortaleza-CE, Brazil
| | - Raimunda Sâmia Nogueira Brilhante
- Department of Pathology and Legal Medicine, School of Medicine, Specialized Medical Mycology Center, Graduate Program in Medical Microbiology, Federal University of Ceará, Fortaleza-CE, Brazil
| | - Marcos Fábio Gadelha Rocha
- Department of Pathology and Legal Medicine, School of Medicine, Specialized Medical Mycology Center, Graduate Program in Medical Microbiology, Federal University of Ceará, Fortaleza-CE, Brazil.,School of Veterinary, Postgraduate Program in Veterinary Sciences, State University of Ceará, 1315 Coronel Nunes de Melo Street, Rodolfo Teófilo, CEP 60420-270, Fortaleza-CE, Brazil
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Howard KC, Dennis EK, Watt DS, Garneau-Tsodikova S. A comprehensive overview of the medicinal chemistry of antifungal drugs: perspectives and promise. Chem Soc Rev 2020; 49:2426-2480. [PMID: 32140691 DOI: 10.1039/c9cs00556k] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The emergence of new fungal pathogens makes the development of new antifungal drugs a medical imperative that in recent years motivates the talents of numerous investigators across the world. Understanding not only the structural families of these drugs but also their biological targets provides a rational means for evaluating the merits and selectivity of new agents for fungal pathogens and normal cells. An equally important aspect of modern antifungal drug development takes a balanced look at the problems of drug potency and drug resistance. The future development of new antifungal agents will rest with those who employ synthetic and semisynthetic methodology as well as natural product isolation to tackle these problems and with those who possess a clear understanding of fungal cell architecture and drug resistance mechanisms. This review endeavors to provide an introduction to a growing and increasingly important literature, including coverage of the new developments in medicinal chemistry since 2015, and also endeavors to spark the curiosity of investigators who might enter this fascinatingly complex fungal landscape.
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Affiliation(s)
- Kaitlind C Howard
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536-0596, USA.
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7
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Sfeir MM, Jiménez-Ortigosa C, Gamaletsou MN, Schuetz AN, Soave R, Van Besien K, Small CB, Perlin DS, Walsh TJ. Breakthrough Bloodstream Infections Caused by Echinocandin-Resistant Candida tropicalis: An Emerging Threat to Immunocompromised Patients with Hematological Malignancies. J Fungi (Basel) 2020; 6:jof6010020. [PMID: 32024039 PMCID: PMC7151208 DOI: 10.3390/jof6010020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 01/27/2020] [Accepted: 01/27/2020] [Indexed: 12/20/2022] Open
Abstract
Background. Candida tropicalis is a virulent fungal pathogen for which echinocandins are the primary therapy. Emergence of resistance to echinocandins of C. tropicalis carries potentially ominous therapeutic implications. Methods. We describe herein two patients with breakthrough C. tropicalis fungemia during echinocandin therapy, characterize their molecular mechanism of resistance, and systematically review 13 previously reported cases of echinocandin-resistant C. tropicalis bloodstream infections (BSIs) and other diseases. Results. Among these 15 patients with echinocandin-resistant C. tropicalis infections, the median age was 61 years (ages 28–84 years) and 13 (86%) were immunocompromised. Thirteen (86%) of all patients had a history of pervious or concurrent exposure to echinocandins. Isolates of C. tropicalis from 11 cases, including the two index cases, underwent DNA sequencing of the FKS1 gene for mutations known to confer echinocandin resistance. The amino acid substitution Ser654Pro was shown in four cases, while other FKS1 mutations encoded Ser80S/Pro, Phe641Leu, Phe641Ser, Ser80S/Pro substitutions. These mutational events were not associated with collateral increases in minimum inhibitory concentrations to antifungal triazoles and amphotericin B. Overall mortality in patients with echinocandin-resistant C. tropicalis infections was 40%. Among those six patients who died, two received monotherapy with voriconazole, one was treated with fluconazole, one remained on caspofungin, and two were switched to liposomal amphotericin B. Nine patients (60%) survived after being treated with an antifungal agent other than an echinocandin. Conclusions. Emergence of resistance to echinocandins by C. tropicalis, occurs during antifungal therapy, is associated with high mortality, is mediated by a diverse range of FKS1 mutations, retains in vitro susceptibility to triazoles and amphotericin B, and constitutes an emerging threat to patients with hematological malignancies.
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Affiliation(s)
- Maroun M. Sfeir
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine and New York Presbyterian Hospital, New York, NY 10065, USA; (M.M.S.); (R.S.); (C.B.S.)
- Department of Healthcare Policy and Research, Weill Cornell Medicine, New York, NY 10065, USA
| | - Cristina Jiménez-Ortigosa
- Public Health Research Institute, New Jersey Medical School/Rutgers Biomedical and Health Sciences, Newark, NJ 07103, USA; (C.J.-O.); (D.S.P.)
| | - Maria N. Gamaletsou
- Department of Pathophysiology, Laikon General Hospital, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece;
| | - Audrey N. Schuetz
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55901, USA;
| | - Rosemary Soave
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine and New York Presbyterian Hospital, New York, NY 10065, USA; (M.M.S.); (R.S.); (C.B.S.)
- Transplantation-Oncology Infectious Diseases Program, Weill Cornell Medicine and New York Presbyterian Hospital, New York, NY 10065, USA
| | - Koen Van Besien
- Division of Hematology/Oncology, Weill Cornell Medicine and New York Presbyterian Hospital, New York, NY 10065, USA;
| | - Catherine B. Small
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine and New York Presbyterian Hospital, New York, NY 10065, USA; (M.M.S.); (R.S.); (C.B.S.)
- Transplantation-Oncology Infectious Diseases Program, Weill Cornell Medicine and New York Presbyterian Hospital, New York, NY 10065, USA
| | - David S. Perlin
- Public Health Research Institute, New Jersey Medical School/Rutgers Biomedical and Health Sciences, Newark, NJ 07103, USA; (C.J.-O.); (D.S.P.)
| | - Thomas J. Walsh
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine and New York Presbyterian Hospital, New York, NY 10065, USA; (M.M.S.); (R.S.); (C.B.S.)
- Transplantation-Oncology Infectious Diseases Program, Weill Cornell Medicine and New York Presbyterian Hospital, New York, NY 10065, USA
- Departments of Pediatrics, and Microbiology & Immunology, Weill Cornell Medicine and New York Presbyterian Hospital, New York, NY 10065, USA
- Correspondence:
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Motamedi M, Saharkhiz MJ, Pakshir K, Amini Akbarabadi S, Alikhani Khordshami M, Asadian F, Zareshahrabadi Z, Zomorodian K. Chemical compositions and antifungal activities of Satureja macrosiphon against Candida and Aspergillus species. Curr Med Mycol 2020; 5:20-25. [PMID: 32104740 PMCID: PMC7034783 DOI: 10.18502/cmm.5.4.2162] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Background and Purpose: Despite the various applications of Satureja species, there are limited data in this domain. Regarding this, the present study was conducted to investigate the essential oil (EO) biological activity of S. macrosiphon species in Iran. Materials and Methods: The EO of S. macrosiphon flowers was obtained by hydrodistillation. Chemical compositions of the EO were analyzed using gas chromatography-mass spectrometry. In addition, minimum inhibitory concentrations (MIC) were measured by means of the broth microdilution method. The estimation of antibiofilm and cytotoxic activities was also accomplished using the tetrazolium salt and MTT assays, respectively. Results: A total of 26 components were identified in the EO with linalool as the main constituent (28.46%). A MIC range value of 0.25-8 μL/mL was obtained against all of the tested fungi. The EO inhibited the biofilm development of the Candida tested strains at a concentration of 4-8 μL/mL. Cytotoxicity (IC50) of EO against the HeLa cell was greater than the MIC concentration (6.49 μL/mL). Conclusion: Based on the findings, it was concluded that the EO of S. macrosiphon has the potential for further use as an antifungal agent.
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Affiliation(s)
- Marjan Motamedi
- Department of Medical Parasitology and Mycology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | | | - Keyvan Pakshir
- Department of Medical Parasitology and Mycology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.,Basic Sciences in Infectious Diseases Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Sara Amini Akbarabadi
- Department of Medical Parasitology and Mycology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Marzieh Alikhani Khordshami
- Department of Medical Parasitology and Mycology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Fatemeh Asadian
- Department of Pathology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Zahra Zareshahrabadi
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Kamiar Zomorodian
- Department of Medical Parasitology and Mycology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.,Basic Sciences in Infectious Diseases Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
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EUCAST Reference Testing of Rezafungin Susceptibility and Impact of Choice of Plastic Plates. Antimicrob Agents Chemother 2019; 63:AAC.00659-19. [PMID: 31285230 DOI: 10.1128/aac.00659-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 06/30/2019] [Indexed: 11/20/2022] Open
Abstract
Rezafungin is a new long-acting echinocandin currently in phase 3 development. Epidemiological cutoff values are necessary for breakpoint setting but have not been established due to unexplained interlaboratory MIC variations observed in a prior multicenter study. Here we investigated if the choice of microtiter plates affected the variability when anidulafungin was included as a comparator. Testing by the EUCAST E.Def 7.3.1 reference method using tissue and cell culture-treated polystyrene plates (TC plates) and untreated polystyrene plates (UT plates) from four manufacturers was performed. Six control strains (Candida albicans, n = 3; C. krusei, n = 2; C. parapsilosis, n = 1) were tested (520 MICs). Subsequently, 5 or 6 wild-type isolates and 4 or 5 fks mutants of C. albicans, C. glabrata, C. krusei, C. parapsilosis (wild type only), and C. tropicalis were tested (930 MICs). For each strain-plate combination, ≥98% of the repetitive MICs were within 3 dilutions. The rezafungin modal MICs for the collated C. albicans control strain distributions were 0.016 mg/liter across TC plates but 0.03 mg/liter across UT plates, whereas they were 0.004 mg/liter and 0.016 mg/liter, respectively, for anidulafungin. The difference was most pronounced with Falcon plates and was not observed for C. krusei and C. parapsilosis Eleven rezafungin MICs for mutants overlapped with the MICs for wild-type isolates (TC plates, n = 4; UT plates, n = 7). For anidulafungin, five overlaps (all UT plates) were observed. Most overlaps (rezafungin, n = 5; anidulafungin, n = 3) were caused by fks mutants of C. tropicalis (Fks1, F650F/L) and C. glabrata (Fks2. D666Y; rezafungin, n = 2; anidulafungin, n = 1). Interlaboratory variation was low. The use of TC plates resulted in lower MICs, particularly for C. albicans and Falcon plates, ad this was more often the case for anidulafungin than for rezafungin. Adoption of TC plates for EUCAST antifungal susceptibility testing would improve interlaboratory reproducibility and the separation of non-wild-type and wild-type strains.
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10
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Facilitators of adaptation and antifungal resistance mechanisms in clinically relevant fungi. Fungal Genet Biol 2019; 132:103254. [PMID: 31326470 DOI: 10.1016/j.fgb.2019.103254] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 07/16/2019] [Accepted: 07/16/2019] [Indexed: 12/12/2022]
Abstract
Opportunistic fungal pathogens can cause a diverse range of diseases in humans. The increasing rate of fungal infections caused by strains that are resistant to commonly used antifungals results in difficulty to treat diseases, with accompanying high mortality rates. Existing and newly emerging molecular resistance mechanisms rapidly spread in fungal populations and need to be monitored. Fungi exhibit a diversity of mechanisms to maintain physiological resilience and create genetic variation; processes which eventually lead to the selection and spread of resistant fungal pathogens. To prevent and anticipate this dispersion, the role of evolutionary factors that drive fungal adaptation should be investigated. In this review, we provide an overview of resistance mechanisms against commonly used antifungal compounds in the clinic and for which fungal resistance has been reported. Furthermore, we aim to summarize and elucidate potent generators of genetic variability across the fungal kingdom that aid adaptation to stressful environments. This knowledge can lead to recognizing potential niches that facilitate fast resistance development and can provide leads for new management strategies to battle the emerging resistant populations in the clinic and the environment.
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11
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Zhang M, Yang X, Wang D, Yu C, Sun S. Antifungal activity of immunosuppressants used alone or in combination with fluconazole. J Appl Microbiol 2018; 126:1304-1317. [PMID: 30307675 DOI: 10.1111/jam.14126] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 09/07/2018] [Accepted: 09/29/2018] [Indexed: 01/26/2023]
Abstract
Fungal infections remain a challenge to clinicians due to the limited available antifungals. With the increasing use of antifungals in clinical practice, drug resistance has been emerging continuously, especially to fluconazole (FLC). Thus, a search for new antifungals and approaches to overcome antifungal resistance is needed. However, the development of new antifungals is usually costly and time consuming; discovering the antifungal activity of non-antifungal agents is one way to address these problems. Interestingly, some researchers have demonstrated that several classes of immunosuppressants (calcineurin inhibitors, glucocorticoids, etc) also displayed potent antifungal activity when used alone or in combination with antifungals, especially with FLC. Some of them could increase FLC's susceptibility against resistant Candida albicans significantly reversing fungal resistance to FLC. This article reviews the antifungal activities of immunosuppressants used alone or in combination with antifungals and their potential antifungal mechanisms that have been discovered so far. Although immunosuppressive agents have been identified as risk factors for fungal infection, we believe these findings are very important for overcoming drug resistance and developing new antifungals.
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Affiliation(s)
- M Zhang
- School of Pharmaceutical Sciences, Taishan Medical University, Taian, Shandong Province, China
| | - X Yang
- Department of Pharmacy, Qianfoshan Hospital Affiliated to Shandong University, Jinan, Shandong Province, China
| | - D Wang
- School of Pharmaceutical Sciences, Taishan Medical University, Taian, Shandong Province, China
| | - C Yu
- Department of Pharmacy, Qianfoshan Hospital Affiliated to Shandong University, Jinan, Shandong Province, China
| | - S Sun
- Department of Pharmacy, Qianfoshan Hospital Affiliated to Shandong University, Jinan, Shandong Province, China
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12
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Hori Y, Shibuya K. Role of FKS Gene in the Susceptibility of Pathogenic Fungi to Echinocandins. Med Mycol J 2018; 59:E31-E40. [PMID: 29848909 DOI: 10.3314/mmj.18.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Echinocandins are antifungal agents that specifically inhibit the biosynthesis of 1,3-β-D-glucan, a major structural component of fungal cell walls. Echinocandins are recommended as first-line or alternative/salvage therapy for candidiasis and aspergillosis in antifungal guidelines of various countries. Resistance to echinocandins has been reported in recent years. The mechanism of echinocandin resistance involves amino acid substitutions in hot spot regions of the FKS gene product, the catalytic subunit of 1,3-β-D-glucan synthase. This resistance mechanism contributes to not only acquired resistance in Candida spp., but also inherent resistance in some pathogenic fungi. An understanding of the echinocandin resistance mechanism is important to develop both effective diagnosis and treatment options for echinocandin-resistant fungal diseases.
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Affiliation(s)
- Yasuhiro Hori
- Department of Surgical Pathology, Toho University School of Medicine
| | - Kazutoshi Shibuya
- Department of Surgical Pathology, Toho University School of Medicine
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Portrait of Matrix Gene Expression in Candida glabrata Biofilms with Stress Induced by Different Drugs. Genes (Basel) 2018; 9:genes9040205. [PMID: 29642649 PMCID: PMC5924547 DOI: 10.3390/genes9040205] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 03/29/2018] [Accepted: 04/05/2018] [Indexed: 01/22/2023] Open
Abstract
(1) Background: Candida glabrata is one of the most significant Candida species associated with severe cases of candidiasis. Biofilm formation is an important feature, closely associated with antifungal resistance, involving alterations of gene expression or mutations, which can result in the failure of antifungal treatments. Hence, the main goal of this work was to evaluate the role of a set of genes, associated with matrix production, in the resistance of C. glabrata biofilms to antifungal drugs. (2) Methods: the determination of the expression of BGL2, XOG1, FKS1, FKS2, GAS2, KNH1, UGP1, and MNN2 genes in 48-h biofilm’s cells of three C. glabrata strains was performed through quantitative real-time PCR (RT-qPCR), after contact with Fluconazole (Flu), Amphotericin B (AmB), Caspofungin (Csf), or Micafungin (Mcf). (3) Results: Mcf induced a general overexpression of the selected genes. It was verified that the genes related to the production of β-1,3-glucans (BGL2, XOG1, GAS2) had the highest expressions. (4) Conclusion: though β-1,6-glucans and mannans are an essential part of the cell and biofilm matrix, C. glabrata biofilm cells seem to contribute more to the replacement of β-1,3-glucans. Thus, these biopolymers seem to have a greater impact on the biofilm matrix composition and, consequently, a role in the biofilm resistance to antifungal drugs.
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Development of Echinocandin Resistance in Candida tropicalis following Short-Term Exposure to Caspofungin for Empiric Therapy. Antimicrob Agents Chemother 2018; 62:AAC.01926-17. [PMID: 29437623 DOI: 10.1128/aac.01926-17] [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: 09/17/2017] [Accepted: 01/22/2018] [Indexed: 12/16/2022] Open
Abstract
Isolation of two echinocandin-resistant Candida tropicalis strains from endotracheal secretions of a patient following short-term exposure to caspofungin is described. Both strains exhibited resistance to echinocandins by Etest and reference broth microdilution, showing a homozygous S645P mutation within the hot spot 1 (HS-1) region of FKS1 and belonging to a unique multilocus sequence type. Other C. tropicalis isolates collected from patients in the same intensive care unit within a 60-day period were susceptible to echinocandins and contained wild-type FKS1 sequences.
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15
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Update from a 12-Year Nationwide Fungemia Surveillance: Increasing Intrinsic and Acquired Resistance Causes Concern. J Clin Microbiol 2018; 56:JCM.01564-17. [PMID: 29212705 DOI: 10.1128/jcm.01564-17] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 11/30/2017] [Indexed: 12/18/2022] Open
Abstract
New data from the years 2012 to 2015 from the Danish National Fungemia Surveillance are reported, and epidemiological trends are investigated in a 12-year perspective (2004 to 2015). During 2012 to 2015, 1,900 of 1,939 (98%) fungal bloodstream isolates were included. The average incidence was 8.4/100,000 inhabitants, and this appears to represent a stabilizing trend after the increase to 10.1/100,000 in 2011. The incidence was higher in males than females (10.0 versus 6.8) and in patients above 50 years, and those changes were mainly driven by an increasing incidence among 80-to-89-year-old males (65.3/100,000 in 2014 to 2015). The proportion of Candida albicans isolates decreased from 2004 to 2015 (64.4% to 42.4%) in parallel with a doubling of the proportion of Candida glabrata isolates (16.5% to 34.6%, P < 0.0001). C. glabrata was more common among females (34.0% versus 30.4% in males). Following an increase in 2004 to 2011, the annual drug use stabilized during the last 2 to 3 years of that time period but remained higher than in other Nordic countries. This was particularly true for the fluconazole and itraconazole use in the primary health care sector, which exceeded the combined national levels of use of these compounds in each of the other Nordic countries. Fluconazole susceptibility decreased (68.5%, 65.2%, and 60.6% in 2004 to 2007, 2008 to 2011, and 2012 to 2015, respectively, P < 0.0001), and echinocandin resistance emerged in Candida (0%, 0.6%, and 1.7%, respectively, P < 0.001). Amphotericin B susceptibility remained high (98.7%). Among 16 (2.7%) echinocandin-resistant C. glabrata isolates (2012 to 2015), 13 harbored FKS mutations and 5 (31%) were multidrug resistant. The epidemiological changes and the increased incidence of intrinsic and acquired resistance emphasize the importance of continued surveillance and of strengthened focus on antifungal stewardship.
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Xiao M, Fan X, Hou X, Chen SC, Wang H, Kong F, Sun ZY, Chu YZ, Xu YC. Clinical characteristics of the first cases of invasive candidiasis in China due to pan-echinocandin-resistant Candida tropicalis and Candida glabrata isolates with delineation of their resistance mechanisms. Infect Drug Resist 2018; 11:155-161. [PMID: 29416360 PMCID: PMC5790075 DOI: 10.2147/idr.s152785] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Echinocandin antifungal agents have become the first-line therapy for invasive candidiasis (IC) in many countries. Despite their increasing use, resistance to this class of drug is, overall, still uncommon. Here, we report two patients from the People's Republic of China with IC, one with infection caused by pan-echinocandin-resistant Candida tropicalis and the other by pan-echinocandin-resistant Candida glabrata. We also describe the mechanisms of drug resistance of these isolates. The echinocandin-resistant C. glabrata isolate was cultured from ascitic fluid of a 46-year-old male patient with intra-abdominal IC developing after surgery in 2012. This patient had had no prior antifungal exposure. The echinocandin-resistant C. tropicalis isolate was cultured from chest drainage fluid of a 60-year-old female patient with severe coronary disease and lung infection. Prior to culture and identification of the isolate, the patient had received micafungin treatment for 19 days. Both isolates were cross-resistant to micafungin, anidulafungin, and caspofungin, with minimum inhibitory concentration values of ≥2 µg/mL. The amino acid substitution E655K was found adjacent to the FKS2 HS1 region of the C. glabrata isolate, while the substitution S80P were found in the FKS1 HS1 region of the C. tropicalis isolate. This report highlights the emergence of echinocandin resistance in two important non-albicans Candida species. Although the overall prevalence of echinocandin resistance is low in the People's Republic of China, monitoring of antifungal susceptibility trends in all Candida species is warranted.
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Affiliation(s)
- Meng Xiao
- Department of Clinical Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, People's Republic of China.,Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, People's Republic of China
| | - Xin Fan
- Department of Clinical Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, People's Republic of China.,Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, People's Republic of China.,Department of Infectious Diseases and Clinical Microbiology, Beijing Chaoyang Hospital, Beijing, People's Republic of China
| | - Xin Hou
- Department of Clinical Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, People's Republic of China.,Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, People's Republic of China.,Graduate School, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, People's Republic of China
| | - Sharon Ca Chen
- Center for Infectious Diseases and Microbiology Laboratory Services, ICPMR, New South Wales Health Pathology, Westmead Hospital, The University of Sydney, NSW, Australia
| | - He Wang
- Department of Clinical Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, People's Republic of China.,Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, People's Republic of China
| | - Fanrong Kong
- Center for Infectious Diseases and Microbiology Laboratory Services, ICPMR, New South Wales Health Pathology, Westmead Hospital, The University of Sydney, NSW, Australia
| | - Zi-Yong Sun
- Department of Clinical Laboratory, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Yun-Zhuo Chu
- Department of Clinical Laboratory, The First Affiliated Hospital of Chinese Medical University, Shenyang, People's Republic of China
| | - Ying-Chun Xu
- Department of Clinical Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, People's Republic of China.,Beijing Key Laboratory for Mechanisms Research and Precision Diagnosis of Invasive Fungal Diseases, Beijing, People's Republic of China
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17
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Zuza-Alves DL, Silva-Rocha WP, Chaves GM. An Update on Candida tropicalis Based on Basic and Clinical Approaches. Front Microbiol 2017; 8:1927. [PMID: 29081766 PMCID: PMC5645804 DOI: 10.3389/fmicb.2017.01927] [Citation(s) in RCA: 121] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 09/21/2017] [Indexed: 01/12/2023] Open
Abstract
Candida tropicalis has emerged as one of the most important Candida species. It has been widely considered the second most virulent Candida species, only preceded by C. albicans. Besides, this species has been recognized as a very strong biofilm producer, surpassing C. albicans in most of the studies. In addition, it produces a wide range of other virulence factors, including: adhesion to buccal epithelial and endothelial cells; the secretion of lytic enzymes, such as proteinases, phospholipases, and hemolysins, bud-to-hyphae transition (also called morphogenesis) and the phenomenon called phenotypic switching. This is a species very closely related to C. albicans and has been easily identified with both phenotypic and molecular methods. In addition, no cryptic sibling species were yet described in the literature, what is contradictory to some other medically important Candida species. C. tropicalis is a clinically relevant species and may be the second or third etiological agent of candidemia, specifically in Latin American countries and Asia. Antifungal resistance to the azoles, polyenes, and echinocandins has already been described. Apart from all these characteristics, C. tropicalis has been considered an osmotolerant microorganism and this ability to survive to high salt concentration may be important for fungal persistence in saline environments. This physiological characteristic makes this species suitable for use in biotechnology processes. Here we describe an update of C. tropicalis, focusing on all these previously mentioned subjects.
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Affiliation(s)
| | | | - Guilherme M. Chaves
- Laboratory of Medical and Molecular Mycology, Department of Clinical and Toxicological Analyses, Federal University of Rio Grande do Norte, Natal, Brazil
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18
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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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Antifungal Resistance, Metabolic Routes as Drug Targets, and New Antifungal Agents: An Overview about Endemic Dimorphic Fungi. Mediators Inflamm 2017; 2017:9870679. [PMID: 28694566 PMCID: PMC5485324 DOI: 10.1155/2017/9870679] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 04/28/2017] [Accepted: 05/23/2017] [Indexed: 12/30/2022] Open
Abstract
Diseases caused by fungi can occur in healthy people, but immunocompromised patients are the major risk group for invasive fungal infections. Cases of fungal resistance and the difficulty of treatment make fungal infections a public health problem. This review explores mechanisms used by fungi to promote fungal resistance, such as the mutation or overexpression of drug targets, efflux and degradation systems, and pleiotropic drug responses. Alternative novel drug targets have been investigated; these include metabolic routes used by fungi during infection, such as trehalose and amino acid metabolism and mitochondrial proteins. An overview of new antifungal agents, including nanostructured antifungals, as well as of repositioning approaches is discussed. Studies focusing on the development of vaccines against antifungal diseases have increased in recent years, as these strategies can be applied in combination with antifungal therapy to prevent posttreatment sequelae. Studies focused on the development of a pan-fungal vaccine and antifungal drugs can improve the treatment of immunocompromised patients and reduce treatment costs.
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20
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Wiederhold NP. Echinocandin Resistance in Candida Species: a Review of Recent Developments. Curr Infect Dis Rep 2016; 18:42. [PMID: 27771864 DOI: 10.1007/s11908-016-0549-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The echinocandins are important agents for the treatment of invasive fungal infections, especially those caused by Candida species. However, as with other antimicrobial agents, microbiologic resistance to this class of antifungal agents has emerged and can result in clinical failure. Several studies have recently reported an increase in echinocandin resistance in Candida glabrata isolates at various medical centers in different geographic regions of the USA. Recent studies have also reported that many of these isolates may also be fluconazole resistant, leaving few treatment options available for clinicians to use in patients with invasive candidiasis caused by this species. Our understanding of the clinical relevance of specific point mutations within the FKS genes that cause echinocandin resistance and risk factors for the development of microbiologic resistance and clinical failure have also increased. The purpose of this review is to discuss echinocandin resistance in Candida species and recent reports that have increased our understanding of this growing clinical problem.
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Affiliation(s)
- Nathan P Wiederhold
- Department of Pathology, Fungus Testing Laboratory, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, 78229, USA.
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Abstract
PURPOSE OF REVIEW We review and offer our clinical perspectives on the emergence of echinocandin-resistant Candida. RECENT FINDINGS Candida FKS gene mutations attenuate echinocandin activity, but overall mutation rates among clinical isolates remain low (Candida glabrata, ∼4%; other species, <1%). Rates are higher with prior echinocandin exposure, exceeding 50% among C. glabrata or Candida albicans isolates causing breakthrough invasive candidiasis. The median duration of prior echinocandin exposure among FKS mutant isolates is ∼100 days. The clinical usefulness of echinocandin susceptibility testing is limited by the low overall prevalence of resistance, and uncertainties surrounding testing methods and interpretation of minimum inhibitory concentrations (MICs). In single-center studies, caspofungin resistance (defined using institution-specific MIC breakpoints) was 32-53% sensitive and 75-95% specific for predicting treatment outcomes of C. glabrata invasive candidiasis; corresponding values for the presence of an FKS mutation were 35-41% and 90-98%. Results were similar using anidulafungin and micafungin MICs. Clinical data are scarce for non-C. glabrata species. SUMMARY Echinocandins remain preferred agents against invasive Candida infections. Susceptibility testing and FKS genotypic testing do not have roles in routine clinical practice, but may be useful in newly-diagnosed patients who are echinocandin-experienced or those who have not responded to echinocandin treatment.
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22
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[Strategies for antifungal treatment failure in intensive care units]. Anaesthesist 2016; 64:643-58. [PMID: 26349425 DOI: 10.1007/s00101-015-0072-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Recent epidemiologic studies reveal both an increasing incidence and an escalation in resistance of invasive fungal infections in intensive care units. Primary therapy fails in 70 % of cases, depending on the underlying pathogens and diseases. The purpose of this review is to raise awareness for the topic of antifungal therapy failure, describe the clinical conditions in which it occurs, and suggest a possible algorithm for handling the situation of suspected primary therapy failure.
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23
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Gonçalves SS, Souza ACR, Chowdhary A, Meis JF, Colombo AL. Epidemiology and molecular mechanisms of antifungal resistance in CandidaandAspergillus. Mycoses 2016; 59:198-219. [DOI: 10.1111/myc.12469] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Revised: 12/14/2015] [Accepted: 12/18/2015] [Indexed: 12/15/2022]
Affiliation(s)
- Sarah Santos Gonçalves
- Laboratório Especial de Micologia, Disciplina de Infectologia, Escola Paulista de Medicina; Universidade Federal de São Paulo; São Paulo SP Brazil
| | - Ana Carolina Remondi Souza
- Laboratório Especial de Micologia, Disciplina de Infectologia, Escola Paulista de Medicina; Universidade Federal de São Paulo; São Paulo SP Brazil
| | - Anuradha Chowdhary
- Department of Medical Mycology; Vallabhbhai Patel Chest Institute; University of Delhi; Delhi India
| | - Jacques F. Meis
- Department of Medical Microbiology and Infectious Diseases; Canisius Wilhelmina Hospital; Nijmegen the Netherlands
- Department of Medical Microbiology; Radboud University Medical Centre; Nijmegen the Netherlands
| | - Arnaldo Lopes Colombo
- Laboratório Especial de Micologia, Disciplina de Infectologia, Escola Paulista de Medicina; Universidade Federal de São Paulo; São Paulo SP Brazil
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Kołaczkowska A, Kołaczkowski M. Drug resistance mechanisms and their regulation in non-albicans Candida species. J Antimicrob Chemother 2016; 71:1438-50. [PMID: 26801081 DOI: 10.1093/jac/dkv445] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Fungal pathogens use various mechanisms to survive exposure to drugs. Prolonged treatment very often leads to the stepwise acquisition of resistance. The limited number of antifungal therapeutics and their mostly fungistatic rather than fungicidal character facilitates selection of resistant strains. These are able to cope with cytotoxic molecules by acquisition of appropriate mutations, re-wiring gene expression and metabolic adjustments. Recent evidence points to the paramount importance of the permeability barrier and cell wall integrity in the process of adaptation to high drug concentrations. Molecular details of basal and acquired drug resistance are best characterized in the most frequent human fungal pathogen, Candida albicans Effector genes directly related to the acquisition of elevated tolerance of this species to azole and echinocandin drugs are well described. The emergence of high-level drug resistance against intrinsically lower susceptibility to azoles in yeast species other than C. albicans is, however, of particular concern. This is due to their steadily increasing contribution to high mortality rates associated with disseminated infections. Recent findings concerning underlying mechanisms associated with elevated drug resistance suggest a link to cell wall and plasma membrane metabolism in non-albicans Candida species.
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Affiliation(s)
- Anna Kołaczkowska
- Department of Biochemistry, Pharmacology and Toxicology, Wroclaw University of Environmental and Life Sciences, Norwida 31, PL 50-375, Wroclaw, Poland
| | - Marcin Kołaczkowski
- Department of Biophysics, Wroclaw Medical University, Chalubinskiego 10, PL50-368, Wroclaw, Poland
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Posttreatment Antifungal Resistance among Colonizing Candida Isolates in Candidemia Patients: Results from a Systematic Multicenter Study. Antimicrob Agents Chemother 2015; 60:1500-8. [PMID: 26711776 DOI: 10.1128/aac.01763-15] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 12/09/2015] [Indexed: 12/16/2022] Open
Abstract
The prevalence of intrinsic and acquired resistance among colonizing Candida isolates from patients after candidemia was investigated systematically in a 1-year nationwide study. Patients were treated at the discretion of the treating physician. Oral swabs were obtained after treatment. Species distributions and MIC data were investigated for blood and posttreatment oral isolates from patients exposed to either azoles or echinocandins for <7 or ≥ 7 days. Species identification was confirmed using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and internal transcribed spacer (ITS) sequencing, susceptibility was examined by EUCAST EDef 7.2 methodology, echinocandin resistance was examined by FKS sequencing, and genetic relatedness was examined by multilocus sequence typing (MLST). One hundred ninety-three episodes provided 205 blood and 220 oral isolates. MLST analysis demonstrated a genetic relationship for 90% of all paired blood and oral isolates. Patients exposed to azoles for ≥ 7 days (n = 93) had a significantly larger proportion of species intrinsically less susceptible to azoles (particularly Candida glabrata) among oral isolates than among initial blood isolates (36.6% versus 12.9%; P < 0.001). A similar shift toward species less susceptible to echinocandins among 85 patients exposed to echinocandins for ≥ 7 days was not observed (4.8% of oral isolates versus 3.2% of blood isolates; P > 0.5). Acquired resistance in Candida albicans was rare (<5%). However, acquired resistance to fluconazole (29.4%; P < 0.05) and anidulafungin (21.6%; P < 0.05) was common in C. glabrata isolates from patients exposed to either azoles or echinocandins. Our findings suggest that the colonizing mucosal microbiota may be an unrecognized reservoir of resistant Candida species, especially C. glabrata, following treatment for candidemia. The resistance rates were high, raising concern in general for patients exposed to antifungal drugs.
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Pfaller MA, Castanheira M. Nosocomial Candidiasis: Antifungal Stewardship and the Importance of Rapid Diagnosis. Med Mycol 2015; 54:1-22. [PMID: 26385381 DOI: 10.1093/mmy/myv076] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 07/20/2015] [Indexed: 01/12/2023] Open
Abstract
Candidemia and other forms of candidiasis are associated with considerable excess mortality and costs. Despite the addition of several new antifungal agents with improved spectrum and potency, the frequency of Candida infection and associated mortality have not decreased in the past two decades. The lack of rapid and sensitive diagnostic tests has led to considerable overuse of antifungal agents resulting in increased costs, selection pressure for resistance, unnecessary drug toxicity, and adverse drug interactions. Both the lack of timely diagnostic tests and emergence of antifungal resistance pose considerable problems for antifungal stewardship. Whereas antifungal stewardship with a focus on nosocomial candidiasis should be able to improve the administration of antifungal therapy in terms of drug selection, proper dose and duration, source control and de-escalation therapy, an important parameter, timeliness of antifungal therapy, remains a victim of slow and insensitive diagnostic tests. Fortunately, new proteomic and molecular diagnostic tools are improving the time to species identification and detection. In this review we will describe the potential impact that rapid diagnostic testing and antifungal stewardship can have on the management of nosocomial candidiasis.
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Affiliation(s)
- Michael A Pfaller
- T2Biosystems, Lexington, Massachusetts JMI Laboratories, North Liberty, Iowa University of Iowa College of Medicine College of Public Health, Iowa City, Iowa
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Abstract
Fungal infections due to Candida and Aspergillus species cause extensive morbidity and mortality, especially among immunosuppressed patients, and antifungal therapy is critical to patient management. Yet only a few drug classes are available to treat invasive fungal diseases, and this problem is compounded by the emergence of antifungal resistance. Echinocandin drugs are the preferred choice to treat candidiasis. They are the first cell wall-active agents and target the fungal-specific enzyme glucan synthase, which catalyzes the biosynthesis of β-1,3-glucan, a key cell wall polymer. Therapeutic failures occur rarely among common Candida species, with the exception of Candida glabrata, which is frequently multidrug resistant. Echinocandin resistance in susceptible species is always acquired during therapy. The mechanism of resistance involves amino acid changes in hot-spot regions of Fks subunits of glucan synthase, which decrease the sensitivity of the enzyme to drug. Cellular stress response pathways lead to drug adaptation, which promotes the formation of resistant fks strains. Clinical factors promoting echinocandin resistance include empiric therapy, prophylaxis, gastrointestinal reservoirs, and intra-abdominal infections. A better understanding of the echinocandin-resistance mechanism, along with cellular and clinical factors promoting resistance, will facilitate more effective strategies to overcome and prevent echinocandin resistance.
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Affiliation(s)
- David S Perlin
- New Jersey Medical School, Rutgers Biomedical and Health Sciences, Public Health Research Institute, Newark, New Jersey
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Abstract
PURPOSE OF REVIEW Echinocandin resistance in Candida is a great concern, as the echinocandin drugs are recommended as first-line therapy for patients with invasive candidiasis. Here, we review recent advances in our understanding of the epidemiology, underlying mechanisms, methods for detection and clinical implications. RECENT FINDINGS Echinocandin resistance has emerged over the recent years. It has been found in most clinically relevant Candida spp., but is most common in C. glabrata with rates exceeding 10% at selected institutions. It is most commonly detected after 3-4 weeks of treatment and is associated with a dismal outcome. An extensive list of mutations in hot spot regions of the genes encoding the target has been characterized and associated with species and drug-specific loss of susceptibility. The updated antifungal susceptibility testing reference methods identify echinocandin-resistant isolates reliably, although the performance of commercial tests is somewhat more variable. Alternative technologies are being developed, including molecular detection and matrix-assisted laser desorption ionization-time of flight. SUMMARY Echinocandin resistance is increasingly encountered and its occurrence makes susceptibility testing essential, particularly in patients with prior exposure. The further development of rapid and user-friendly commercially available susceptibility platforms is warranted. Antifungal stewardship is important in order to minimize unnecessary selection pressure.
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Pfaller MA, Rhomberg PR, Messer SA, Jones RN, Castanheira M. Isavuconazole, micafungin, and 8 comparator antifungal agents' susceptibility profiles for common and uncommon opportunistic fungi collected in 2013: temporal analysis of antifungal drug resistance using CLSI species-specific clinical breakpoints and proposed epidemiological cutoff values. Diagn Microbiol Infect Dis 2015; 82:303-13. [PMID: 25986029 DOI: 10.1016/j.diagmicrobio.2015.04.008] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 04/21/2015] [Accepted: 04/24/2015] [Indexed: 10/23/2022]
Abstract
The in vitro activities of isavuconazole, micafungin, and 8 comparator antifungal agents were determined for 1613 clinical isolates of fungi (1320 isolates of Candida spp., 155 of Aspergillus spp., 103 of non-Candida yeasts, and 35 non-Aspergillus molds) collected during a global survey conducted in 2013. The vast majority of the isolates of the 21 different species of Candida, with the exception of Candida glabrata (MIC90, 2 μg/mL), Candida krusei (MIC90, 1 μg/mL), and Candida guilliermondii (MIC90, 8 μg/mL), were inhibited by ≤0.25 μg/mL of isavuconazole. C. glabrata and C. krusei were largely inhibited by ≤1 μg/mL of isavuconazole. Resistance to fluconazole was seen in 0.5% of Candida albicans isolates, 11.1% of C. glabrata isolates, 2.5% of Candida parapsilosis isolates, 4.5% of Candida tropicalis isolates, and 20.0% of C. guilliermondii isolates. Resistance to the echinocandins was restricted to C. glabrata (1.3-2.1%) and C. tropicalis (0.9-1.8%). All agents except for the echinocandins were active against 69 Cryptococcus neoformans isolates, and the triazoles, including isavuconazole, were active against the other yeasts. Both the mold active triazoles as well as the echinocandins were active against 155 Aspergillus spp. isolates belonging to 10 species/species complex. In general, there was low resistance levels to the available systemically active antifungal agents in a large, contemporary (2013), global collection of molecularly characterized yeasts and molds. Resistance to azoles and echinocandins was most prominent among isolates of C. glabrata, C. tropicalis, and C. guilliermondii.
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Affiliation(s)
- M A Pfaller
- University of Iowa College of Medicine, Iowa City, IA; JMI Laboratories, North Liberty, IA.
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Quick Detection of FKS1 Mutations Responsible for Clinical Echinocandin Resistance in Candida albicans. J Clin Microbiol 2015; 53:2037-41. [PMID: 25878347 DOI: 10.1128/jcm.00398-15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Accepted: 04/09/2015] [Indexed: 01/02/2023] Open
Abstract
A rapid molecular-based assay for the detection of the Candida albicans FKS1 gene mutations responsible for resistance to echinocandin drugs was designed and evaluated. The assay consisted of a multiplexed PCR set of 5 tubes able to detect the most commonly described resistance mechanism, including FKS1 hot spot 1 and hot spot 2 mutations. The performance and specificity of the assay was evaluated using a double-blinded panel of 50 C. albicans strains. The assay showed a sensitivity of 96% and was able to detect all homozygous mutants included in the collection of strains, demonstrating that it is a robust, quick, and labor-saving method that is suitable for a routine clinical diagnostic laboratory.
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Morace G, Perdoni F, Borghi E. Antifungal drug resistance in Candida species. J Glob Antimicrob Resist 2014; 2:254-259. [PMID: 27873684 DOI: 10.1016/j.jgar.2014.09.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 08/28/2014] [Accepted: 09/09/2014] [Indexed: 11/15/2022] Open
Abstract
Invasive Candida infections are well established infectious entities of immunocompromised or critically ill patients and are characterised by high morbidity and mortality. Owing to the common eukaryotic structure of fungi and humans, a limited number of antifungal drugs is available for therapeutic purposes. In this unsatisfactory scenario, the emergence of drug resistance represents an important health problem. Failure of antifungal treatment can be related to host factors, to the pharmacokinetic and pharmacodynamic parameters of the drug, or to morphological, reproductive modalities and biofilm production of the fungus itself. Innate or acquired antifungal resistance derives from the presence or onset of molecular mechanisms related to the toxic activity of the drug itself. The resulting resistance can thus be extended to different molecules of the same class according to a greater or lesser affinity of the molecules for the target. In addition, non-specific cellular mechanisms of extrusion of toxic substances, such as overexpression of efflux pumps, can play a role involving different antifungal classes. Here we briefly review the current antifungal susceptibility testing methods and their usefulness as predictors of antifungal resistance in Candida spp., focusing on assessment of the involved molecular mechanisms.
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Affiliation(s)
- Giulia Morace
- Department of Health Sciences, Università degli Studi di Milano, Blocco C, via A. di Rudinì 8, 20142 Milan, Italy.
| | - Federica Perdoni
- Department of Health Sciences, Università degli Studi di Milano, Blocco C, via A. di Rudinì 8, 20142 Milan, Italy
| | - Elisa Borghi
- Department of Health Sciences, Università degli Studi di Milano, Blocco C, via A. di Rudinì 8, 20142 Milan, Italy
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Perlin DS. Echinocandin resistance, susceptibility testing and prophylaxis: implications for patient management. Drugs 2014; 74:1573-85. [PMID: 25255923 PMCID: PMC4201113 DOI: 10.1007/s40265-014-0286-5] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
This article addresses the emergence of echinocandin resistance among Candida species, mechanisms of resistance, factors that promote resistance and confounding issues surrounding standard susceptibility testing. Fungal infections remain a significant cause of global morbidity and mortality, especially among patients with underlying immunosupression. Antifungal therapy is a critical component of patient management for acute and chronic diseases. Yet, therapeutic choices are limited due to only a few drug classes available to treat systemic disease. Moreover, the problem is exacerbated by the emergence of antifungal resistance, which has resulted in difficult to manage multidrug resistant strains. Echinocandin drugs are now the preferred choice to treat a range of candidiasis. These drugs target and inhibit the fungal-specific enzyme glucan synthase, which is responsible for the biosynthesis of a key cell wall polymer. Therapeutic failures involving acquisition of resistance among susceptible organisms like Candida albicans is largely a rare event. However, in recent years, there is an alarming trend of increased resistance among strains of Candida glabrata, which in many cases are also resistant to azole drugs. Echinocandin resistance is always acquired during therapy and the mechanism of resistance is well established to involve amino acid changes in "hot-spot" regions of the Fks subunits carrying the catalytic portion of glucan synthase. These changes significantly decrease the sensitivity of the enzyme to drug resulting in higher MIC values. A range of drug responses, from complete to partial refractory response, is observed depending on the nature of the amino acid substitution, and clinical responses are recapitulated in pharmacodynamic models of infection. The cellular processes promoting the formation of resistant Fks strains involve complex stress response pathways, which yield a variety of adaptive compensatory genetic responses. Stress-adapted cells become drug tolerant and can form stable drug resistant FKS mutations with continued drug exposure. A major concern for resistance detection is that classical broth microdilution techniques show significant variability among clinical microbiology laboratories for certain echinocandin drugs and Candida species. The consequence is that susceptible strains are misclassified according to established clinical breakpoints, and this has led to confusion in the field. Clinical factors that appear to promote echinocandin resistance include the expanding use of antifungal agents for empiric therapy and prophylaxis. Furthermore, host reservoirs such as biofilms in the gastrointestinal tract or intra-abdominal infections can seed development of resistant organisms during therapy. A fundamental understanding of the primary molecular resistance mechanism, along with cellular and clinical factors that promote resistance emergence, is critical to develop better diagnostic tools and therapeutic strategies to overcome and prevent echinocandin resistance.
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Affiliation(s)
- David S Perlin
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, 07103, USA,
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Lackner M, Tscherner M, Schaller M, Kuchler K, Mair C, Sartori B, Istel F, Arendrup MC, Lass-Flörl C. Positions and numbers of FKS mutations in Candida albicans selectively influence in vitro and in vivo susceptibilities to echinocandin treatment. Antimicrob Agents Chemother 2014; 58:3626-35. [PMID: 24733467 PMCID: PMC4068606 DOI: 10.1128/aac.00123-14] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 04/06/2014] [Indexed: 02/05/2023] Open
Abstract
Candidemia is the fourth most common kind of microbial bloodstream infection, with Candida albicans being the most common causative species. Echinocandins are employed as the first-line treatment for invasive candidiasis until the fungal species is determined and confirmed by clinical diagnosis. Echinocandins block the FKS glucan synthases responsible for embedding β-(1,3)-d-glucan in the cell wall. The increasing use of these drugs has led to the emergence of antifungal resistance, and elevated MICs have been associated with single-residue substitutions in specific hot spot regions of FKS1 and FKS2. Here, we show for the first time the caspofungin-mediated in vivo selection of a double mutation within one allele of the FKS1 hot spot 1 in a clinical isolate. We created a set of isogenic mutants and used a hematogenous murine model to evaluate the in vivo outcomes of echinocandin treatment. Heterozygous and homozygous double mutations significantly enhance the in vivo resistance of C. albicans compared with the resistance seen with heterozygous single mutations. The various FKS1 hot spot mutations differ in the degree of their MIC increase, substance-dependent in vivo response, and impact on virulence. Our results demonstrate that echinocandin EUCAST breakpoint definitions correlate with the in vivo response when a standard dosing regimen is used but cannot predict the in vivo response after a dose escalation. Moreover, patients colonized by a C. albicans strain with multiple mutations in FKS1 have a higher risk for therapeutic failure.
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Affiliation(s)
- M Lackner
- Division of Hygiene and Medical Microbiology, Innsbruck Medical University, Innsbruck, Austria
| | - M Tscherner
- Medical University of Vienna, Department for Medical Biochemistry, Max F. Perutz Laboratories, Vienna, Austria
| | - M Schaller
- Universitäts-Hautklinik Tübingen, Eberhard-Karls-Universität Tübingen, Tübingen, Germany
| | - K Kuchler
- Medical University of Vienna, Department for Medical Biochemistry, Max F. Perutz Laboratories, Vienna, Austria
| | - C Mair
- Division of Hygiene and Medical Microbiology, Innsbruck Medical University, Innsbruck, Austria
| | - B Sartori
- Division of Hygiene and Medical Microbiology, Innsbruck Medical University, Innsbruck, Austria
| | - F Istel
- Medical University of Vienna, Department for Medical Biochemistry, Max F. Perutz Laboratories, Vienna, Austria
| | - M C Arendrup
- Unit of Mycology, Microbiology and Infection Control, Statens Serum Institut, Copenhagen, Denmark
| | - C Lass-Flörl
- Division of Hygiene and Medical Microbiology, Innsbruck Medical University, Innsbruck, Austria
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Gerstein AC, Kuzmin A, Otto SP. Loss-of-heterozygosity facilitates passage through Haldane's sieve for Saccharomyces cerevisiae undergoing adaptation. Nat Commun 2014; 5:3819. [PMID: 24804896 DOI: 10.1038/ncomms4819] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 04/08/2014] [Indexed: 11/09/2022] Open
Abstract
Haldane's sieve posits that the majority of beneficial mutations that contribute to adaptation should be dominant, as these are the mutations most likely to establish and spread when rare. It has been argued, however, that if the dominance of mutations in their current and previous environments are correlated, Haldane's sieve could be eliminated. We constructed heterozygous lines of Saccharomyces cerevisiae containing single adaptive mutations obtained during exposure to the fungicide nystatin. Here we show that no clear dominance relationship exists across environments: mutations exhibited a range of dominance levels in a rich medium, yet were exclusively recessive under nystatin stress. Surprisingly, heterozygous replicates exhibited variable-onset rapid growth when exposed to nystatin. Targeted Sanger sequencing demonstrated that loss-of-heterozygosity (LOH) accounted for these growth patterns. Our experiments demonstrate that recessive beneficial mutations can avoid Haldane's sieve in clonal organisms through rapid LOH and thus contribute to rapid evolutionary adaptation.
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Affiliation(s)
- A C Gerstein
- 1] Biodiversity Research Centre, Department of Zoology, The University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4 [2]
| | - A Kuzmin
- Biodiversity Research Centre, Department of Zoology, The University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | - S P Otto
- Biodiversity Research Centre, Department of Zoology, The University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
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Alcazar-Fuoli L, Mellado E. Current status of antifungal resistance and its impact on clinical practice. Br J Haematol 2014; 166:471-84. [PMID: 24749533 DOI: 10.1111/bjh.12896] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 03/17/2014] [Indexed: 11/30/2022]
Abstract
Mortality linked to invasive fungal diseases remains very high despite the availability of novel antifungals and new therapeutic strategies. Candida albicans and Aspergillus fumigatus account for most invasive mycosis produced by yeast or moulds, respectively. Other Candida non-albicans are increasingly being reported and newly emerging, as well as cryptic, filamentous fungi often cause disseminated infections in immunocompromised hosts. Management of invasive fungal infections is becoming a challenge as emerging fungal pathogens generally show poor response to many antifungals. The ability of reference antifungal susceptibility testing methods to detect emerging resistance patterns, together with the molecular characterization of antifungal resistance mechanisms, are providing useful information to optimize the effectiveness of antifungal therapy. The current status of antifungal resistance epidemiology with special emphasis on the molecular resistant mechanisms that have been described in the main pathogenic fungal species are reviewed.
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Affiliation(s)
- Laura Alcazar-Fuoli
- Mycology Reference Laboratory, Centro Nacional de Microbiologia, Instituto de Salud Carlos III, Madrid, Spain
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37
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Echinocandin failure case due to a previously unreported FKS1 mutation in Candida krusei. Antimicrob Agents Chemother 2014; 58:3550-2. [PMID: 24687511 DOI: 10.1128/aac.02367-14] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Echinocandins are the preferred therapy for invasive infections due to Candida krusei. We present here a case of clinical failure involving C. krusei with a characteristic FKS1 hot spot mutation not previously reported in C. krusei that was isolated after 14 days of treatment. Anidulafungin MICs were elevated by ≥ 5 dilution steps above the clinical breakpoint but by only 1 step for a Candida albicans isolate harboring the corresponding mutation, suggesting a notable species-specific difference in the MIC increase conferred by this mutation.
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38
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Cuenca-Estrella M. Antifungal drug resistance mechanisms in pathogenic fungi: from bench to bedside. Clin Microbiol Infect 2014; 20 Suppl 6:54-9. [PMID: 24372680 DOI: 10.1111/1469-0691.12495] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The phenotypic methods for identification of antifungal resistance are reliable procedures, and MIC determination by reference techniques is the gold standard to detect resistant clinical isolates. In recent years, progress has been made towards the description of resistance mechanisms at molecular level. There are methods of detection that can be useful for clinical laboratories, but lack of standardization precludes their full and effective integration in the routine daily practice. The molecular detection of Candida resistance to azoles and to echinocandins and of Aspergillus resistance to triazoles can be clinically relevant and could help to design more efficient prevention and control strategies. This text reviews the present state of the detection of mechanisms of resistance at the molecular level in Candida spp. and Aspergillus spp. and its relevance to clinical practice.
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Affiliation(s)
- M Cuenca-Estrella
- National Center for Microbiology, Instituto de Salud Carlos III, Madrid, Spain
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Arendrup MC, Cuenca-Estrella M, Lass-Flörl C, Hope WW. Breakpoints for antifungal agents: an update from EUCAST focussing on echinocandins against Candida spp. and triazoles against Aspergillus spp. Drug Resist Updat 2014; 16:81-95. [PMID: 24618110 DOI: 10.1016/j.drup.2014.01.001] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Candida and Aspergillus infections have emerged as significant pathogens in recent decades. During this same time, broad spectrum triazole and echinocandin antifungal agents have been developed and increasingly used. One consequence of widespread use is leading to the emergence of mutants with acquired resistance mutations. Therefore, accurate susceptibility testing and appropriate clinical breakpoints for the interpretation of susceptibility results have become increasingly important. Here we review the underlying methodology by which breakpoints have been selected by EUCAST (European Committee on Antimicrobial Susceptibility Testing). Five parameters are evaluated: dosing regimens used; EUCAST MIC distributions from multiple laboratories, species and compound specific epidemiological cut off values (upper MIC limits of wild type isolates or ECOFFs), pharmacokinetic/pharmacodynamic relationships and targets associated with outcome and finally clinical data by species and MIC when available. The general principles are reviewed followed by a detailed review of the individual aspects for Candida species and the three echinocandins and for Aspergillus and the three mould-active azoles. This review provides an update of the subcommittee on antifungal susceptibility testing (AFST) of the EUCAST methodology and summarises the current EUCAST breakpoints for Candida and Aspergillus. Recommendations about applicability of antifungal susceptibility testing in the routine setting are also included.
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Affiliation(s)
- Maiken C Arendrup
- Unit of Mycology, Dept. Microbiology & Infection Control, Statens Serum Institut, Copenhagen, Denmark.
| | | | - Cornelia Lass-Flörl
- Division of Hygiene and Medical Microbiology, Innsbruck Medical University, Austria
| | - William W Hope
- Antimicrobial Pharmacodynamics and Therapeutics, Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, United Kingdom
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Calcineurin controls hyphal growth, virulence, and drug tolerance of Candida tropicalis. EUKARYOTIC CELL 2014; 13:844-54. [PMID: 24442892 DOI: 10.1128/ec.00302-13] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Candida tropicalis, a species closely related to Candida albicans, is an emerging fungal pathogen associated with high mortality rates of 40 to 70%. Like C. albicans and Candida dubliniensis, C. tropicalis is able to form germ tubes, pseudohyphae, and hyphae, but the genes involved in hyphal growth machinery and virulence remain unclear in C. tropicalis. Recently, echinocandin- and azole-resistant C. tropicalis isolates have frequently been isolated from various patients around the world, making treatment difficult. However, studies of the C. tropicalis genes involved in drug tolerance are limited. Here, we investigated the roles of calcineurin and its potential target, Crz1, for core stress responses and pathogenesis in C. tropicalis. We demonstrate that calcineurin and Crz1 are required for hyphal growth, micafungin tolerance, and virulence in a murine systemic infection model, while calcineurin but not Crz1 is essential for tolerance of azoles, caspofungin, anidulafungin, and cell wall-perturbing agents, suggesting that calcineurin has both Crz1-dependent and -independent functions in C. tropicalis. In addition, we found that calcineurin and Crz1 have opposite roles in controlling calcium tolerance. Calcineurin serves as a negative regulator, while Crz1 plays a positive role for calcium tolerance in C. tropicalis.
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41
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Pfaller MA, Messer SA, Diekema DJ, Jones RN, Castanheira M. Use of micafungin as a surrogate marker to predict susceptibility and resistance to caspofungin among 3,764 clinical isolates of Candida by use of CLSI methods and interpretive criteria. J Clin Microbiol 2014; 52:108-14. [PMID: 24153129 PMCID: PMC3911432 DOI: 10.1128/jcm.02481-13] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 10/18/2013] [Indexed: 11/20/2022] Open
Abstract
Due to unacceptably high interlaboratory variation in caspofungin MIC values, we evaluated the use of micafungin as a surrogate marker to predict the susceptibility of Candida spp. to caspofungin using reference methods and species-specific interpretive criteria. The MIC results for 3,764 strains of Candida (eight species), including 73 strains with fks mutations, were used. Caspofungin MIC values and species-specific interpretive criteria were compared with those of micafungin to determine the percent categorical agreement (%CA) and very major error (VME), major error (ME), and minor error rates as well as their ability to detect fks mutant strains of Candida albicans (11 mutants), Candida tropicalis (4 mutants), Candida krusei (3 mutants), and Candida glabrata (55 mutants). Overall, the %CA was 98.8% (0.2% VMEs and MEs, 0.8% minor errors) using micafungin as the surrogate marker. Among the 60 isolates of C. albicans (9 isolates), C. tropicalis (5 isolates), C. krusei (2 isolates), and C. glabrata (44 isolates) that were nonsusceptible (either intermediate or resistant) to both caspofungin and micafungin, 54 (90.0%) contained a mutation in fks1 or fks2. An additional 10 C. glabrata mutants, two C. albicans mutants, and one mutant each of C. tropicalis and C. krusei were classified as susceptible to both antifungal agents. Using the epidemiological cutoff values (ECVs) of 0.12 μg/ml for caspofungin and 0.03 μg/ml for micafungin to differentiate wild-type (WT) from non-WT strains of C. glabrata, 80% of the C. glabrata mutants were non-WT for both agents (96% concordance). Micafungin may serve as an acceptable surrogate marker for the prediction of susceptibility and resistance of Candida to caspofungin.
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Affiliation(s)
- Michael A. Pfaller
- JMI Laboratories, North Liberty, Iowa, USA
- University of Iowa, Iowa City, Iowa, USA
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Arendrup M, Dzajic E, Jensen R, Johansen H, Kjaldgaard P, Knudsen J, Kristensen L, Leitz C, Lemming L, Nielsen L, Olesen B, Rosenvinge F, Røder B, Schønheyder H. Epidemiological changes with potential implication for antifungal prescription recommendations for fungaemia: data from a nationwide fungaemia surveillance programme. Clin Microbiol Infect 2013; 19:E343-53. [DOI: 10.1111/1469-0691.12212] [Citation(s) in RCA: 157] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 01/24/2013] [Accepted: 02/24/2013] [Indexed: 01/18/2023]
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