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Misra A, Powell EA. Preanalytical Challenges of Molecular Microbiology Tests. Clin Lab Med 2024; 44:33-43. [PMID: 38280796 DOI: 10.1016/j.cll.2023.10.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2024]
Abstract
As infectious disease diagnostics increasingly incorporates molecular techniques, there are unique preanalytical concerns that must be considered. First, noninvasive specimen types that may be inadequate for culture-based diagnostics may be acceptable when using molecular tests. Second, specimen containers must be evaluated for the presence of substances that may interfere with amplification or sequencing reactions. Finally, the capacity of transport, storage, and processing conditions to maintain nucleic acid integrity and avoid contamination must be assessed. This review explores these issues and the effects they may have on result quality.
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Affiliation(s)
- Anisha Misra
- Department of Laboratory Medicine, Cleveland Clinic, Robert J. Tomsich Pathology and Laboratory Medicine Institute, 10300 Carnegie Avenue LL-1, Cleveland, OH 44195, USA
| | - Eleanor A Powell
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, 3188 Bellevue Avenue, Cincinnati, OH 45219, USA.
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2
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Gudisa R, Harchand R, Rudramurthy SM. Nucleic-Acid-Based Molecular Fungal Diagnostics: A Way to a Better Future. Diagnostics (Basel) 2024; 14:520. [PMID: 38472992 DOI: 10.3390/diagnostics14050520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 02/20/2024] [Accepted: 02/27/2024] [Indexed: 03/14/2024] Open
Abstract
The world has seen a tremendous increase in the number of fungal infections during the past two decades. Recently, the World Health Organisation released the pathogen priority list for fungal infections, signifying the importance of these infections in the fields of research and public health. Microbiology laboratories demand an upgrade in the diagnostic system to keep up with the increased burden of these infections. Diagnosis of fungal infections using conventional techniques has always faced limitations in terms of specificity, sensitivity, and turnaround time. Although these methods are the core pillars of the diagnosis, there is an increased need for molecular approaches. Molecular techniques have revolutionised the field of fungal diagnostics. The diverse array of molecular techniques, including techniques like Polymerase Chain Reaction (PCR), have emerged as a cornerstone in fungal diagnostics. Molecular techniques have transformed fungal diagnostics, providing powerful tools for the rapid and accurate identification of pathogens. As these technologies continue to evolve, their integration into routine clinical practice holds the promise of improving patient outcomes through timely and targeted antifungal interventions. This review will cover the molecular approaches involved in fungal diagnostics, moving from the basic techniques to the advanced-level nucleic-acid-based molecular approaches providing a high throughput and decreased turnaround time for the diagnosis of serious fungal infections.
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Affiliation(s)
- Rajendra Gudisa
- Department of Medical Microbiology, Post Graduate Institute of Medical Education and Research, Chandigarh 160012, India
| | - Ritika Harchand
- Department of Medical Microbiology, Post Graduate Institute of Medical Education and Research, Chandigarh 160012, India
| | - Shivaprakash M Rudramurthy
- Department of Medical Microbiology, Post Graduate Institute of Medical Education and Research, Chandigarh 160012, India
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3
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Wang J, Meng S, Lin K, Yi X, Sun Y, Xu X, He N, Zhang Z, Hu H, Qie X, Zhang D, Tang Y, Huang WE, He J, Song Y. Leveraging single-cell Raman spectroscopy and single-cell sorting for the detection and identification of yeast infections. Anal Chim Acta 2023; 1239:340658. [PMID: 36628751 DOI: 10.1016/j.aca.2022.340658] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 11/21/2022] [Accepted: 11/21/2022] [Indexed: 11/26/2022]
Abstract
Invasive fungal infection serves as a great threat to human health. Discrimination between fungal and bacterial infections at the earliest stage is vital for effective clinic practice; however, traditional culture-dependent microscopic diagnosis of fungal infection usually requires several days, meanwhile, culture-independent immunological and molecular methods are limited by the detectable type of pathogens and the issues with high false-positive rates. In this study, we proposed a novel culture-independent phenotyping method based on single-cell Raman spectroscopy for the rapid discrimination between fungal and bacterial infections. Three Raman biomarkers, including cytochrome c, peptidoglycan, and nucleic acid, were identified through hierarchical clustering analysis of Raman spectra across 12 types of most common yeast and bacterial pathogens. Compared to those of bacterial pathogens, the single cells of yeast pathogens demonstrated significantly stronger Raman peaks for cytochrome c, but weaker signals for peptidoglycan and nucleic acid. A two-step protocol combining the three biomarkers was established and able to differentiate fungal infections from bacterial infections with an overall accuracy of 94.9%. Our approach was also used to detect ten raw urinary tract infection samples. Successful identification of fungi was achieved within half an hour after sample obtainment. We further demonstrated the accurate fungal species taxonomy achieved with Raman-assisted cell ejection. Our findings demonstrate that Raman-based fungal identification is a novel, facile, reliable, and with a breadth of coverage approach, that has a great potential to be adopted in routine clinical practice to reduce the turn-around time of invasive fungal disease (IFD) diagnostics.
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Affiliation(s)
- Jingkai Wang
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, 215163, China; Division of Life Sciences and Medicine, School of Biomedical Engineering (Suzhou), University of Science and Technology of China, Suzhou, 215163, China
| | - Siyu Meng
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, 215163, China
| | - Kaicheng Lin
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, 215163, China
| | - Xiaofei Yi
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, 20040, China; National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, 200040, China
| | - Yixiang Sun
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, 215163, China
| | - Xiaogang Xu
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, 20040, China; National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, 200040, China
| | - Na He
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, 215163, China
| | - Zhiqiang Zhang
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, 215163, China
| | - Huijie Hu
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, 215163, China; Division of Life Sciences and Medicine, School of Biomedical Engineering (Suzhou), University of Science and Technology of China, Suzhou, 215163, China
| | - Xingwang Qie
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, 215163, China
| | - Dayi Zhang
- College of New Energy and Environment, Jilin University, Changchun, 130021, PR China
| | - Yuguo Tang
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, 215163, China
| | - Wei E Huang
- Department of Engineering Science, University of Oxford, Parks Road, Oxford, OX1 3PJ, UK
| | - Jian He
- State Key Laboratory of Oncogenes and Related Genes, Center for Single-Cell Omics, School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
| | - Yizhi Song
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, 215163, China; Division of Life Sciences and Medicine, School of Biomedical Engineering (Suzhou), University of Science and Technology of China, Suzhou, 215163, China.
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4
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Wingard JR, Alexander BD, Baden LR, Chen M, Sugrue MW, Leather HL, Caliendo AM, Clancy CJ, Denning DW, Marty FM, Nguyen MH, Wheat LJ, Logan BR, Horowitz MM, Marr KA. Impact of Changes of the 2020 Consensus Definitions of Invasive Aspergillosis on Clinical Trial Design: Unintended Consequences for Prevention Trials? Open Forum Infect Dis 2021; 8:ofab441. [PMID: 34631917 PMCID: PMC8496761 DOI: 10.1093/ofid/ofab441] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 08/23/2021] [Indexed: 12/20/2022] Open
Abstract
Background Consensus definitions for the diagnosis of invasive fungal diseases (IFDs) were updated in 2020 to increase the certainty of IFD for inclusion in clinical trials, for instance by increasing biomarker cutoff limits to define positivity. To date, there is a paucity of data as to the impact of the revised definitions on clinical trials. Methods In this study, we sought to determine the impact of the new definitions on classifying invasive aspergillosis (IA), the most common invasive mold disease in immunocompromised patients. We reclassified 226 proven and probable IA cases plus 139 possible IFD cases in the Aspergillus Technology Consortium (AsTeC) and in an antifungal prophylaxis trial (BMT CTN 0101) using the new criteria. Results Fewer cases met the more stringent diagnostic 2020 criteria after applying the reclassification criteria to define probable IA. Of 188 evaluable probable cases, 41 (22%) were reclassified to 40 possible IA and 1 probable IFD. Reclassification to possible IFD occurred in 22% of hematologic malignancy (HM) patients, 29% of hematopoietic cell transplant (HCT) patients, and in no lung transplant (LT) patients. Date of diagnosis was established a median (range) of 3 (1–105) days later in 15% of probable IA cases using the new criteria. Applying the new definitions to the BMT CTN 0101 trial, the power to detect the same odds ratio decreased substantially. Conclusions The updated IA consensus definitions may impact future trial designs, especially for antifungal prophylaxis studies.
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Affiliation(s)
- John R Wingard
- Department of Medicine, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Barbara D Alexander
- Departments of Medicine and Pathology, Duke University, Durham, North Carolina, USA
| | - Lindsey R Baden
- Department of Medicine, Dana-Farber Cancer Institute and Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Min Chen
- CIBMTR Milwaukee, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Michele W Sugrue
- Department of Medicine, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Helen L Leather
- Department of Medicine, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Angela M Caliendo
- Department of Medicine, The Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
| | - Cornelius J Clancy
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - David W Denning
- Division of Infection, Immunity and Respiratory Medicine, University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Francisco M Marty
- Department of Medicine, Dana-Farber Cancer Institute and Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - M Hong Nguyen
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | | | - Brent R Logan
- CIBMTR Milwaukee, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Mary M Horowitz
- CIBMTR Milwaukee, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Kieren A Marr
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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5
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Lockhart SR, Bialek R, Kibbler CC, Cuenca-Estrella M, Jensen HE, Kontoyiannis DP. Molecular Techniques for Genus and Species Determination of Fungi From Fresh and Paraffin-Embedded Formalin-Fixed Tissue in the Revised EORTC/MSGERC Definitions of Invasive Fungal Infection. Clin Infect Dis 2021; 72:S109-S113. [PMID: 33709128 PMCID: PMC7952508 DOI: 10.1093/cid/ciaa1836] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The EORTC/MSGERC have revised the definitions for proven, probable, and possible fungal diseases. The tissue diagnosis subcommittee was tasked with determining how and when species can be determined from tissue in the absence of culture. The subcommittee reached a consensus decision that polymerase chain reaction (PCR) from tissue, but not immunohistochemistry or in situ hybridization, can be used for genus or species determination under the new EORTC/MSGERC guidelines, but only when fungal elements are identified by histology. Fungal elements seen in tissue samples by histopathology and identified by PCR followed by sequencing should fulfill the definition of a proven fungal infection, identified to genus/species, even in the absence of culture. This summary discusses the issues that were deliberated by the subcommittee to reach the consensus decision and outlines the criteria a laboratory should follow in order to produce data that meet the EORTC/MSGERC definitions.
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Affiliation(s)
- Shawn R Lockhart
- Mycotic Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Ralf Bialek
- LADR GmbH MVZ Dr. Kramer und Kollegen, Geesthacht, Germany
| | | | - Manuel Cuenca-Estrella
- Laboratorio de referencia e investigación en Micología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Spain
| | - Henrik E Jensen
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Dimitrios P Kontoyiannis
- Department of Infectious Diseases, Infection Control and Employee Health, The University of Texas M.D. Anderson Cancer Center, Houston, Texas, USA
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6
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Lysen C, Silva-Flannery L, Zaki SR, Gary JM, Lockhart SR. Performance evaluation of fungal DNA PCR amplification from formalin-fixed paraffin-embedded tissue for diagnosis: Experience of a tertiary reference laboratory. Mycoses 2021; 64:603-611. [PMID: 33527526 DOI: 10.1111/myc.13249] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 01/22/2021] [Accepted: 01/23/2021] [Indexed: 12/15/2022]
Abstract
BACKGROUND Diagnosis of invasive fungal infections from formalin-fixed paraffin-embedded (FFPE) tissues by PCR amplification is a developing technology. One of the difficulties of establishing a validated protocol for this testing is that the gold standard, culture, is much less sensitive than the test being validated. OBJECTIVES To validate FFPE PCR as a refence laboratory identification methodology in the absence of abundant gold standard specimens. METHODS In this validation, PCR from FFPE tissue was compared to other diagnostic methods for genus/species identification. Four different groups of correlative data from FFPE tissues were used to validate this procedure. Thirteen specimens had culture or serology results and FFPE PCR results, 49 specimens had both immunohistochemistry (IHC) identification and FFPE PCR results, 118 specimens had histological evidence of fungal elements, 64 of which also had FFPE PCR results, and 36 fungal mock tissues or fungal negative tissues were used. RESULTS The sensitivity determined from the tissues with positive fungal histopathology was 54%. The specificity of the cases for which there were both culture and FFPE PCR results was 100%. For the correlation with IHC, the specificity was 98%. For the mock tissues and fungal negative tissues, the calculated analytical sensitivity was 94%, specificity was 95%, and accuracy was 94%. CONCLUSIONS By uniquely combining various data sources, this study provides a comprehensive framework for how validation can be achieved in the absence of a gold standard and outlines the excellent performance of PCR from FFPE tissue, despite relatively the low sensitivity when compared to histopathology.
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Affiliation(s)
- Colleen Lysen
- Mycotic Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Luciana Silva-Flannery
- Infectious Disease Pathology Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Sherif R Zaki
- Infectious Disease Pathology Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Joy M Gary
- Infectious Disease Pathology Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Shawn R Lockhart
- Mycotic Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
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8
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Kidd SE, Chen SCA, Meyer W, Halliday CL. A New Age in Molecular Diagnostics for Invasive Fungal Disease: Are We Ready? Front Microbiol 2020; 10:2903. [PMID: 31993022 PMCID: PMC6971168 DOI: 10.3389/fmicb.2019.02903] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 12/02/2019] [Indexed: 12/18/2022] Open
Abstract
Invasive fungal diseases (IFDs) present an increasing global burden in immunocompromised and other seriously ill populations, including those caused by pathogens which are inherently resistant or less susceptible to antifungal drugs. Early diagnosis encompassing accurate detection and identification of the causative agent and of antifungal resistance is critical for optimum patient outcomes. Many molecular-based diagnostic approaches have good clinical utility although interpretation of results should be according to clinical context. Where an IFD is in the differential diagnosis, panfungal PCR assays allow the rapid detection/identification of fungal species directly from clinical specimens with good specificity; sensitivity is also high when hyphae are seen in the specimen including in paraffin-embedded tissue. Aspergillus PCR assays on blood fractions have good utility in the screening of high risk hematology patients with high negative predictive value (NPV) and positive predictive value (PPV) of 94 and 70%, respectively, when two positive PCR results are obtained. The standardization, and commercialization of Aspergillus PCR assays has now enabled direct comparison of results between laboratories with commercial assays also offering the simultaneous detection of common azole resistance mutations. Candida PCR assays are not as well standardized with the only FDA-approved commercial system (T2Candida) detecting only the five most common species; while the T2Candida outperforms blood culture in patients with candidemia, its role in routine Candida diagnostics is not well defined. There is growing use of Mucorales-specific PCR assays to detect selected genera in blood fractions. Quantitative real-time Pneumocystis jirovecii PCRs have replaced microscopy and immunofluorescent stains in many diagnostic laboratories although distinguishing infection may be problematic in non-HIV-infected patients. For species identification of isolates, DNA barcoding with dual loci (ITS and TEF1α) offer optimal accuracy while next generation sequencing (NGS) technologies offer highly discriminatory analysis of genetic diversity including for outbreak investigation and for drug resistance characterization. Advances in molecular technologies will further enhance routine fungal diagnostics.
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Affiliation(s)
- Sarah E. Kidd
- National Mycology Reference Centre, Microbiology and Infectious Diseases, South Australia Pathology, Adelaide, SA, Australia
| | - Sharon C.-A. Chen
- Centre for Infectious Diseases and Microbiology Laboratory Services, ICPMR, New South Wales Health Pathology, Westmead Hospital, Westmead, NSW, Australia
- Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, Sydney, NSW, Australia
| | - Wieland Meyer
- Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, Sydney, NSW, Australia
- Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Faculty of Medicine and Health, Westmead Clinical School, The University of Sydney, Sydney, NSW, Australia
- The Westmead Institute for Medical Research, Westmead, NSW, Australia
- Research and Education Network, Westmead Hospital, Westmead, NSW, Australia
| | - Catriona L. Halliday
- Centre for Infectious Diseases and Microbiology Laboratory Services, ICPMR, New South Wales Health Pathology, Westmead Hospital, Westmead, NSW, Australia
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Sousa V, Gomes ATPC, Freitas A, Faustino MAF, Neves MGPMS, Almeida A. Photodynamic Inactivation of Candida albicans in Blood Plasma and Whole Blood. Antibiotics (Basel) 2019; 8:antibiotics8040221. [PMID: 31766190 PMCID: PMC6963715 DOI: 10.3390/antibiotics8040221] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 11/10/2019] [Accepted: 11/11/2019] [Indexed: 11/17/2022] Open
Abstract
The few approved disinfection techniques for blood derivatives promote damage in the blood components, representing risks for the transfusion receptor. Antimicrobial photodynamic therapy (aPDT) seems to be a promising approach for the photoinactivation of pathogens in blood, but only three photosensitizers (PSs) have been approved, methylene blue (MB) for plasma and riboflavin and amotosalen for plasma and platelets. In this study, the efficiency of the porphyrinic photosensitizer Tri-Py(+)-Me and of the porphyrinic formulation FORM was studied in the photoinactivation of Candida albicans in plasma and in whole blood and the results were compared to the ones obtained with the already approved PS MB. The results show that FORM and Tri-Py(+)-Me are promising PSs to inactivate C. albicans in plasma. Although in whole blood the inactivation rates obtained were higher than the ones obtained with MB, further improvements are required. None of these PSs had promoted hemolysis at the isotonic conditions when hemolysis was evaluated in whole blood and after the addition of treated plasma with these PSs to concentrates of red blood cells.
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Affiliation(s)
- Vera Sousa
- Department of Biology & CESAM, University of Aveiro, Aveiro 3810-193, Portugal;
| | - Ana T. P. C. Gomes
- Department of Biology & CESAM, University of Aveiro, Aveiro 3810-193, Portugal;
- Correspondence: (A.T.P.C.G.); (M.A.F.F.); (A.A.)
| | - Américo Freitas
- Clinical Analysis Laboratory Avelab, Rua Cerâmica do Vouga, Aveiro 3800-011, Portugal;
| | - Maria A. F. Faustino
- Department of Chemistry & QOPNA and LAQV-REQUIMTE, University of Aveiro, Aveiro 3810-193, Portugal;
- Correspondence: (A.T.P.C.G.); (M.A.F.F.); (A.A.)
| | - Maria G. P. M. S. Neves
- Department of Chemistry & QOPNA and LAQV-REQUIMTE, University of Aveiro, Aveiro 3810-193, Portugal;
| | - Adelaide Almeida
- Department of Biology & CESAM, University of Aveiro, Aveiro 3810-193, Portugal;
- Correspondence: (A.T.P.C.G.); (M.A.F.F.); (A.A.)
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Saffioti C, Mesini A, Bandettini R, Castagnola E. Diagnosis of invasive fungal disease in children: a narrative review. Expert Rev Anti Infect Ther 2019; 17:895-909. [PMID: 31694414 DOI: 10.1080/14787210.2019.1690455] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Introduction: Invasive fungal diseases (IFD) represent important causes of morbidity and mortality in pediatrics. Early diagnosis and treatment of IFD is associated with better outcome and this entails the need to use fast and highly sensitive and specific methods that can support clinicians in the management of IFD.Areas covered: A narrative review was performed on conventional diagnostic methods such as culture, microscopy and histopathology are still gold standard but are burdened by a lack of sensitivity and specificity; on the other hand, imaging and noninvasive antigen-based such as beta-D-glucan, galactomannan and molecular biomarkers are the most convenient nonculture methods for diagnosis and monitoring effects of therapy. Aim of the present review is to summarize what is available in these fields at end of the second decade of the third millennium and look for future perspectives.Expert opinion: Promising and useful diagnostic methods have been applied in infectious disease diagnosis in clinical practice or in designing platforms. Unfortunately, most of them are not standardized or validated in pediatric population. However, clinicians should be aware of all innovative diagnostic tools to use in combination with conventional diagnostic methods for a better management of pathology and patient.
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Affiliation(s)
- Carolina Saffioti
- Department of Infectious Diseases, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Alessio Mesini
- Department of Infectious Diseases, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Roberto Bandettini
- Department of laboratory Medicine, Microbiology Service, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Elio Castagnola
- Department of Infectious Diseases, IRCCS Istituto Giannina Gaslini, Genoa, Italy
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11
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Lockhart SR, Gary JM. Is This Zebra Really a Zebra? The Challenge of Diagnosing Rare Fungal Infections in Veterinary Pathology. Vet Pathol 2019; 56:510-511. [PMID: 31185881 DOI: 10.1177/0300985819843684] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Shawn R Lockhart
- 1 Mycotic Diseases Branch and Infectious Disease Pathology Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Joy M Gary
- 2 Infectious Disease Pathology Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA
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12
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Barnes RA, White PL, Morton CO, Rogers TR, Cruciani M, Loeffler J, Donnelly JP. Diagnosis of aspergillosis by PCR: Clinical considerations and technical tips. Med Mycol 2018; 56:60-72. [PMID: 29087518 DOI: 10.1093/mmy/myx091] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 08/29/2017] [Indexed: 12/25/2022] Open
Abstract
Standardization of Aspergillus polymerase chain reaction (PCR) protocols has progressed, and analytical validity of blood-based assays has been formally established. It remains necessary to consider how the tests can be used in practice to maximize clinical utility. To determine the optimal diagnostic strategies and influence on patient management, several factors require consideration, including the patient population, incidence of invasive aspergillosis (and other fungal disease), and the local antifungal prescribing policy. Technical issues such as specimen type, ease of sampling, frequency of testing, access to testing centers, and time to reporting will also influence the use of PCR in clinical practice. Interpretation of all diagnostic tests is dependent on the clinical context and molecular assays are no exception, but with the proposal to incorporate Aspergillus PCR into the second revision of the consensus guidelines for defining invasive fungal disease the acceptance and understanding of molecular tests should improve.
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Affiliation(s)
| | - P Lewis White
- Public Health Wales Microbiology Cardiff, Cardiff, UK
| | | | | | - Mario Cruciani
- Center of Community Medicine and Infectious Diseases Service, ULSS 20 Verona
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13
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Lorenz MG, Lustig M, Linow M. Fungal-Grade Reagents and Materials for Molecular Analysis. Methods Mol Biol 2018; 1508:141-150. [PMID: 27837501 DOI: 10.1007/978-1-4939-6515-1_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
Abstract
Fungal DNA is present at very low loads in clinical specimens. Molecular detection by amplification assays generally is a challenge because of a potentially multiple input of contaminating DNA from exogenous sources. Besides airborne, handling and cross-contamination, materials and reagents used in the molecular laboratory can contain microbial DNA which is a long underestimated potential source of false positive results. In this contribution decontamination procedures of materials and reagents and the selection of certified microbial DNA-free components for sample collection, DNA extraction, and PCR amplification are discussed with respect to the aim of building up a reliable molecular system for the diagnosis of fungal organisms at the limit of detection.
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Affiliation(s)
- Michael G Lorenz
- Molzym GmbH & Co. KG, Mary-Astell-Str. 10, Bremen, 28359, Germany.
| | - Michael Lustig
- Molzym GmbH & Co. KG, Mary-Astell-Str. 10, Bremen, 28359, Germany
| | - Marina Linow
- Molzym GmbH & Co. KG, Mary-Astell-Str. 10, Bremen, 28359, Germany
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14
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Alanio A, Menotti J, Gits-Muselli M, Hamane S, Denis B, Rafoux E, Peffault de la Tour R, Touratier S, Bergeron A, Guigue N, Bretagne S. Circulating Aspergillus fumigatus DNA Is Quantitatively Correlated to Galactomannan in Serum. Front Microbiol 2017; 8:2040. [PMID: 29163378 PMCID: PMC5671575 DOI: 10.3389/fmicb.2017.02040] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 10/05/2017] [Indexed: 12/20/2022] Open
Abstract
The performance of antigen galactomannan (GM) for diagnosing invasive aspergillosis (IA) is hampered by the occurrence of false-positive results. Quantitative PCR has been proposed to improve the diagnosis of IA. Therefore, we analyzed the value of performing a PCR test to the GM-positive serum sample. Using a quantitative PCR assay specific for Aspergillus fumigatus 28S ribosomal DNA, we retrospectively tested 422 GM-positive (Platelia Bio-Rad kit) serum samples collected over 1 year from 147 patients. The cases were classified based on EORTC criteria as “proven,” “probable,” and “no–IA” before availability of the PCR results. After exclusion of 65 samples for non-reproducibility of GM positivity (n = 62) or PCR inhibition (n = 3), 75 (21.0%) of the remaining 357 samples were PCR-positive. GM and fungal DNA showed a significantly positive correlation (p < 0.0001, R2 = 0.27, slope = 0.98 ± 0.19). At least one PCR-positive result was observed in 63.3% (31/49) of IA patients and in 13.2% (13/98) of non-IA patients (p < 0.0001). The PCR positivity was also associated with the presence of other microbiological criteria among the 44 patients with IA and complete mycological workup (p = 0.014), as well as a higher mortality rate at six months among the 135 patients with hematological conditions (p = 0.0198). Overall, we found a quantitative correlation between serum GM and circulating DNA with an increased likelihood of IA when both were positive. A PCR-positive result also supported a higher fungal load when GM was already positive. We advocate adding a PCR test for every confirmed GM-positive serum sample.
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Affiliation(s)
- Alexandre Alanio
- Laboratoire de Parasitologie-Mycologie, APHP, Paris, France.,Université Paris-Diderot, Université Sorbonne Paris Cité, Paris, France.,Unité de Mycologie Moléculaire, Institut Pasteur, CNRS URA 3012, Centre National de Référence des Mycoses Invasives et des Antifongiques, URA 3012, Paris, France
| | - Jean Menotti
- Laboratoire de Parasitologie-Mycologie, APHP, Paris, France.,Université Paris-Diderot, Université Sorbonne Paris Cité, Paris, France
| | - Maud Gits-Muselli
- Laboratoire de Parasitologie-Mycologie, APHP, Paris, France.,Université Paris-Diderot, Université Sorbonne Paris Cité, Paris, France
| | - Samia Hamane
- Laboratoire de Parasitologie-Mycologie, APHP, Paris, France
| | - Blandine Denis
- Service de Maladie Infectieuses et Tropicales, AP-HP, Paris, France
| | | | - Régis Peffault de la Tour
- Université Paris-Diderot, Université Sorbonne Paris Cité, Paris, France.,Service d'Hématologie-Greffe de Moelle, APHP, Paris, France
| | | | - Anne Bergeron
- Université Paris-Diderot, Université Sorbonne Paris Cité, Paris, France.,Service de Pneumologie, APHP, Paris, France
| | - Nicolas Guigue
- Laboratoire de Parasitologie-Mycologie, APHP, Paris, France
| | - Stéphane Bretagne
- Laboratoire de Parasitologie-Mycologie, APHP, Paris, France.,Université Paris-Diderot, Université Sorbonne Paris Cité, Paris, France.,Unité de Mycologie Moléculaire, Institut Pasteur, CNRS URA 3012, Centre National de Référence des Mycoses Invasives et des Antifongiques, URA 3012, Paris, France
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15
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Volatile Organic Compounds: Upcoming Role in Diagnosis of Invasive Mould Infections. CURRENT FUNGAL INFECTION REPORTS 2017. [DOI: 10.1007/s12281-017-0284-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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16
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Yeasts. Microbiol Spectr 2017; 4. [PMID: 27726781 DOI: 10.1128/microbiolspec.dmih2-0030-2016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Yeasts are unicellular organisms that reproduce mostly by budding and less often by fission. Most medically important yeasts originate from Ascomycota or Basidiomycota. Here, we review taxonomy, epidemiology, disease spectrum, antifungal drug susceptibility patterns of medically important yeast, laboratory diagnosis, and diagnostic strategies.
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17
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Abstract
Invasive aspergillosis (IA) has been increasingly reported in populations other than the historical hematology patients and there are new questions about the performance of microbiological tools. Microscopy and culture have been completed by biomarkers, either antigens or DNA, and in blood or respiratory specimens or both. First studied in hematology, the antigen galactomannan performance in serum is low in other patient populations where the pathophysiology of the infection can be different and the prevalence of IA is much lower. DNA detection with polymerase chain reaction (PCR) in blood or serum (or both) has reached a certain level of acceptance thanks to consensus methods based on real-time quantitative PCR (qPCR). When used on respiratory specimens, galactomannan and qPCR depend on standardization of the sampling and the diverse mycological procedures. Thus, culture remains the main diagnostic criterion in critically ill patients. The current trend toward more effective anti-mold prophylaxis in hematology hampers the yield of a screening strategy, as is usually performed in hematology. Therefore, circulating biomarkers as confirmatory tests should be considered and their performance should be reappraised in each new setting. The use of azole prophylaxis also raises the issue of selecting azole-resistance Aspergillus fumigatus isolates. Ideally, the biomarkers will be more efficient when individual genetic risks of IA are defined. Culture, though not standardized, remains a key element for the diagnosis of IA and has the advantage to easily detect molds other than A. fumigatus. It is still unclear whether next-generation sequencing will replace culture in the future.
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Affiliation(s)
- Alexandre Alanio
- Parasitology-Mycology Laboratory, Lariboisière Saint-Louis Fernand Widal hospitals, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France; Paris-Diderot, Sorbonne Paris Cité University, Paris, France; Institut Pasteur, CNRS, Molecular Mycology Unit, Reference National Center of Invasive Mycoses and Antifungals, Paris, France
| | - Stéphane Bretagne
- Parasitology-Mycology Laboratory, Lariboisière Saint-Louis Fernand Widal hospitals, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France; Paris-Diderot, Sorbonne Paris Cité University, Paris, France; Institut Pasteur, CNRS, Molecular Mycology Unit, Reference National Center of Invasive Mycoses and Antifungals, Paris, France
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18
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Lackner M, Lass-Flörl C. Commercial Molecular Tests for Fungal Diagnosis from a Practical Point of View. Methods Mol Biol 2017; 1508:85-105. [PMID: 27837499 DOI: 10.1007/978-1-4939-6515-1_4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The increasing interest in molecular diagnostics is a result of tremendously improved knowledge on fungal infections in the past 20 years and the rapid development of new methods, in particular polymerase chain reaction. High expectations have been placed on molecular diagnostics, and the number of laboratories now using the relevant technology is rapidly increasing-resulting in an obvious need for standardization and definition of laboratory organization. In the past 10 years, multiple new molecular tools were marketed for the detection of DNA, antibodies, cell wall components, or other antigens. In contrast to classical culture methods, molecular methods do not detect a viable organisms, but only molecules which indicate its presence; this can be nucleic acids, cell components (antigens), or antibodies (Fig. 1). In this chapter, an overview is provided on commercially available detection tools, their strength and how to use them. A main focus is laid on providing tips and tricks that make daily life easier. We try to focus and mention methodical details which are not highlighted in the manufacturer's instructions of these test kits, but are based on our personal experience in the laboratory. Important to keep in mind is that molecular tools cannot replace culture, microscopy, or a critical view on patients' clinical history, signs, and symptoms, but provide a valuable add on tool. Diagnosis should not be based solely on a molecular test, but molecular tools might deliver an important piece of information that helps matching the diagnostic puzzle to a diagnosis, in particular as few tests are in vitro diagnostic tests (IVD) or only part of the whole test carries the IVD certificate (e.g., DNA extraction is often not included). Please be aware that the authors do not claim to provide a complete overview on all commercially available diagnostic assays being currently marketed for fungal detection, as those are subject to constant change. A main focus is put on commonly used panfungal assays and pathogen-specific assays, including Aspergillus-specific, Candida-specific, Cryptococcus specific, Histoplasma-specific, and Pneumocystis-specific assays. Assays are categorized according to their underlying principle in either antigen-detecting or antibody-detecting or DNA-detecting (Fig. 1). Other non-DNA-detecting nucleic acid methods such as FISH and PNA FISH are not summarized in this chapter and an overview on test performance, common false positives, and the clinical evaluation of commercial tests in studies is provided already in a previous book series by Javier Yugueros Marcos and David H. Pincus (Marcos and Pincus, Methods Mol Biol 968:25-54, 2013).
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Affiliation(s)
- Michaela Lackner
- Division of Hygiene and Medical Microbiology, Medical University of Innsbruck, Schöpfstrasse 41, Innsbruck, 6020, Austria.
| | - Cornelia Lass-Flörl
- Division of Hygiene and Medical Microbiology, Medical University of Innsbruck, Schöpfstrasse 41, Innsbruck, 6020, Austria
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19
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Detection and Management of Fungal Respiratory Infection by Using Molecular Markers. Fungal Biol 2017. [DOI: 10.1007/978-3-319-34106-4_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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20
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Abstract
PCR can aid in the diagnosis of invasive fungal disease (IFD). While the large number of "in-house" methodologies drives technological diversity, providing robustness, they make it difficult to identify optimal strategies, limiting standardization, and widespread acceptance. No matter how efficient, PCR utility will be limited by the quality of extracted nucleic acid. This chapter highlights benefits and limitations affecting the nucleic acid extraction process, before focusing on recent recommendations that through multicenter evaluation have provided optimal and standardized methodology.
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Affiliation(s)
- P Lewis White
- Public Health Wales Microbiology Cardiff, University Hospital of Wales, Heath Park, Cardiff, CF14 4XW, UK.
| | - Rosemary A Barnes
- Public Health Wales Microbiology Cardiff, University Hospital of Wales, Heath Park, Cardiff, CF14 4XW, UK.,Department of Infection and Immunity, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK
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Abstract
Nucleic acid amplification methods facilitate rapid and sensitive detection of clinically relevant fungal pathogens, and can be employed using a variety of patient specimens. However, contamination from various exogenous sources constitutes a serious threat to the validity of amplification-based fungal assays. In this chapter, common origins of fungal contaminants that compromise molecular fungal testing are described, and measures for preventing contamination are proposed. Detailed guidelines for sample handling, reagent selection, contamination screening, and decontamination procedures are provided.
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Abstract
Fungal diagnostics that utilize antibody, antigen or nucleic acid detection offer several advantages that supplement traditional culture-based methods. As a group, nonculture assays can help identify patients with invasive fungal infection (IFI) sooner than is possible with culture, are often more sensitive, and can be used to guide early interventions. Challenges associated with these techniques include the possibility for contamination or cross-reactivity as well as the potential for false negative tests. This review summarized the test characteristics and clinical utility of nonculture-based laboratory methods.
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Affiliation(s)
| | - Kimberly E Hanson
- Department of Medicine, Division of Infectious Diseases, University of Utah School of Medicine, 30 N 1900E, Room 4B319, Salt Lake City, UT 84132, USA; Department of Pathology, University of Utah School of Medicine, 15 N Medical Drive East, Suite 1100, Salt Lake City, UT 84122, USA.
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23
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Alanio A, Bretagne S. Performance evaluation of multiplex PCR including Aspergillus-not so simple! Med Mycol 2016; 55:56-62. [PMID: 27664168 DOI: 10.1093/mmy/myw080] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 04/25/2016] [Accepted: 07/08/2016] [Indexed: 12/30/2022] Open
Abstract
Multiplex PCRs have been designed for including species other than Aspergillus fumigatus for the diagnosis of invasive aspergillosis, such as microarrays, liquid-phase array, and electrospray-ionization mass spectrometry (PCR/ESI MS). These methods are based on the selection of multiple primers to amplify different species with the specificity checked by hybridization to a probe or by base composition of the amplicon for the PCR/ESI MS. When testing complex samples such as respiratory specimens, some clinically relevant species can be missed. Indeed, it is impossible to design primers able to amplify all the known fungal species with the same efficiency. Therefore, the best amplified species may not be the most clinically relevant. Multiplex assays have also been proposed to detect A. fumigatus DNA and azole resistance. Since the gene responsible for azole resistance is single copy and the gene used for detection is multicopy, only the high fungal loads can be evaluated. Thus, although interesting for investigating mycobiome, the multiplex assays should be used with cautious for the diagnosis of IA or the detection of resistance. For the diagnosis of invasive aspergillosis, validated quantitative PCRs specifically targeting A. fumigatus or a limited set of species to increase sensitivity is a safer option.
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Affiliation(s)
- Alexandre Alanio
- Paris-Diderot, Sorbonne Paris Cité University.,Parasitology-Mycology Laboratory, Saint-Louis Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP).,Institut Pasteur, Molecular Mycology Unit, CNRS URA3012, National Reference Center of Invasive Mycoses and Antifungals, Paris, France
| | - Stéphane Bretagne
- Paris-Diderot, Sorbonne Paris Cité University .,Parasitology-Mycology Laboratory, Saint-Louis Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP).,Institut Pasteur, Molecular Mycology Unit, CNRS URA3012, National Reference Center of Invasive Mycoses and Antifungals, Paris, France
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24
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Abstract
The direct detection of Aspergillus nucleic acid in clinical specimens has the potential to improve the diagnosis of aspergillosis by offering more rapid and sensitive identification of invasive infections than is possible with traditional techniques, such as culture or histopathology. Molecular tests for Aspergillus have been limited historically by lack of standardization and variable sensitivities and specificities. Recent efforts have been directed at addressing these limitations and optimizing assay performance using a variety of specimen types. This review provides a summary of standardization efforts and outlines the complexities of molecular testing for Aspergillus in clinical mycology.
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25
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Broad-Range PCR Coupled with Electrospray Ionization Time of Flight Mass Spectrometry for Detection of Bacteremia and Fungemia in Patients with Neutropenic Fever. J Clin Microbiol 2016; 54:2513-20. [PMID: 27440820 DOI: 10.1128/jcm.01066-16] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 07/18/2016] [Indexed: 11/20/2022] Open
Abstract
Infection is an important complication in patients with hematologic malignancies or solid tumors undergoing intensive cytotoxic chemotherapy. In only 20 to 30% of the febrile neutropenic episodes, an infectious agent is detected by conventional cultures. In this prospective study, the performance of broad-range PCR coupled with electrospray ionization time of flight mass spectrometry (PCR/ESI-MS) technology was compared to conventional blood cultures (BC) in a consecutive series of samples from high-risk hematology patients. In 74 patients, BC and a whole-blood sample for PCR/ESI-MS (Iridica BAC BSI; Abbott, Carlsbad, CA, USA) were collected at the start of each febrile neutropenic episode and, in case of persistent fever, also at day 5. During 100 different febrile episodes, 105 blood samples were collected and analyzed by PCR/ESI-MS. There was evidence of a bloodstream infection (BSI) in 36/105 cases (34%), based on 14 cases with both PCR/ESI-MS and BC positivity, 17 cases with BC positivity only, and 5 cases with PCR/ESI-MS positivity only. The sensitivity of PCR/ESI-MS was 45%, specificity was 93%, and the negative predictive value was 80% compared to blood culture. PCR/ESI-MS detected definite pathogens (Fusobacterium nucleatum and Streptococcus pneumoniae) missed by BC, whereas it missed both Gram-negative and Gram-positive organisms detected by BC. PCR/ESI-MS testing detected additional microorganisms but showed a low sensitivity (45%) compared to BC in neutropenic patients. Our results indicate a lower concordance between BC and PCR/ESI-MS in the neutropenic population than what has been previously reported in other patient groups with normal white blood cell distribution, and a lower sensitivity than other PCR-based methods.
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26
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Abstract
ABSTRACT
Filamentous mycoses are often associated with significant morbidity and mortality. Prompt diagnosis and aggressive treatment are essential for good clinical outcomes in immunocompromised patients. The host immune response plays an essential role in determining the course of exposure to potential fungal pathogens. Depending on the effectiveness of immune response and the burden of organism exposure, fungi can either be cleared or infection can occur and progress to a potentially fatal invasive disease. Nonspecific cellular immunity (i.e., neutrophils, natural killer [NK] cells, and macrophages) combined with T-cell responses are the main immunologic mechanisms of protection. The most common potential mold pathogens include certain hyaline hyphomycetes, endemic fungi, the
Mucorales
, and some dematiaceous fungi. Laboratory diagnostics aimed at detecting and differentiating these organisms are crucial to helping clinicians make informed decisions about treatment. The purpose of this chapter is to provide an overview of the medically important fungal pathogens, as well as to discuss the patient characteristics, antifungal-therapy considerations, and laboratory tests used in current clinical practice for the immunocompromised host.
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Springer J, Lackner M, Nachbaur D, Girschikofsky M, Risslegger B, Mutschlechner W, Fritz J, Heinz W, Einsele H, Ullmann A, Löffler J, Lass-Flörl C. Prospective multicentre PCR-based Aspergillus DNA screening in high-risk patients with and without primary antifungal mould prophylaxis. Clin Microbiol Infect 2016; 22:80-86. [DOI: 10.1016/j.cmi.2015.09.009] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 08/13/2015] [Accepted: 09/08/2015] [Indexed: 11/29/2022]
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White PL, Wingard JR, Bretagne S, Löffler J, Patterson TF, Slavin MA, Barnes RA, Pappas PG, Donnelly JP. Aspergillus Polymerase Chain Reaction: Systematic Review of Evidence for Clinical Use in Comparison With Antigen Testing. Clin Infect Dis 2015; 61:1293-303. [PMID: 26113653 PMCID: PMC4583581 DOI: 10.1093/cid/civ507] [Citation(s) in RCA: 133] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 06/13/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Aspergillus polymerase chain reaction (PCR) was excluded from the European Organisation for the Research and Treatment of Cancer/Mycoses Study Group (EORTC/MSG) definitions of invasive fungal disease because of limited standardization and validation. The definitions are being revised. METHODS A systematic literature review was performed to identify analytical and clinical information available on inclusion of galactomannan enzyme immunoassay (GM-EIA) (2002) and β-d-glucan (2008), providing a minimal threshold when considering PCR. Categorical parameters and statistical performance were compared. RESULTS When incorporated, GM-EIA and β-d-glucan sensitivities and specificities for diagnosing invasive aspergillosis were 81.6% and 91.6%, and 76.9% and 89.4%, respectively. Aspergillus PCR has similar sensitivity and specificity (76.8%-88.0% and 75.0%-94.5%, respectively) and comparable utility. Methodological recommendations and commercial PCR assays assist standardization. Although all tests have limitations, currently, PCR is the only test with independent quality control. CONCLUSIONS We propose that there is sufficient evidence that is at least equivalent to that used to include GM-EIA and β-d-glucan testing, and that PCR is now mature enough for inclusion in the EORTC/MSG definitions.
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Affiliation(s)
- P. Lewis White
- Public Health Wales, Microbiology Cardiff, United Kingdom
| | | | | | | | - Thomas F. Patterson
- University of Texas Health Science Center and South Texas Veterans Health Care System, San Antonio
| | - Monica A. Slavin
- Peter MacCallum Cancer Centre, University of Melbourne, Australia
| | - Rosemary A. Barnes
- Infection, Immunity and Biochemistry, Cardiff University, United Kingdom
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29
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Haidar G, Falcione BA, Nguyen MH. Diagnostic Modalities for Invasive Mould Infections among Hematopoietic Stem Cell Transplant and Solid Organ Recipients: Performance Characteristics and Practical Roles in the Clinic. J Fungi (Basel) 2015; 1:252-276. [PMID: 29376911 PMCID: PMC5753113 DOI: 10.3390/jof1020252] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2015] [Revised: 08/28/2015] [Accepted: 08/31/2015] [Indexed: 12/19/2022] Open
Abstract
The morbidity and mortality of hematopoietic stem cell and solid organ transplant patients with invasive fungal infections (IFIs) remain high despite an increase in the number of effective antifungal agents. Early diagnosis leading to timely administration of antifungal therapy has been linked to better outcomes. Unfortunately, the diagnosis of IFIs remains challenging. The current gold standard for diagnosis is a combination of histopathology and culture, for which the sensitivity is <50%. Over the past two decades, a plethora of non-culture-based antigen and molecular assays have been developed and clinically validated. In this article, we will review the performance of the current commercially available non-cultural diagnostics and discuss their practical roles in the clinic.
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Affiliation(s)
- Ghady Haidar
- Department of Medicine, University of Pittsburgh Medical Center, Scaife Hall, Suite 871, 3550 Terrace Street, Pittsburgh, PA 15261, USA.
| | - Bonnie A Falcione
- Department of Medicine, University of Pittsburgh Medical Center, Scaife Hall, Suite 871, 3550 Terrace Street, Pittsburgh, PA 15261, USA.
- Department of Pharmacy and Therapeutics, University of Pittsburgh School of Pharmacy, 200 Lothrop St. 301, Pittsburgh, PA 15213, USA.
- Department of Medicine, University of Pittsburgh, Scaife Hall, Suite 871, 3550 Terrace Street, Pittsburgh, PA 15261, USA.
| | - M Hong Nguyen
- Department of Medicine, University of Pittsburgh Medical Center, Scaife Hall, Suite 871, 3550 Terrace Street, Pittsburgh, PA 15261, USA.
- Department of Medicine, University of Pittsburgh, Scaife Hall, Suite 871, 3550 Terrace Street, Pittsburgh, PA 15261, USA.
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Rickerts V. Identification of fungal pathogens in Formalin-fixed, Paraffin-embedded tissue samples by molecular methods. Fungal Biol 2015; 120:279-87. [PMID: 26781382 DOI: 10.1016/j.funbio.2015.07.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 06/28/2015] [Accepted: 07/06/2015] [Indexed: 10/23/2022]
Abstract
The etiology of invasive fungal infections (IFI) is incompletely understood due to diagnostic limitations including insensitivity of cultures and failure of histopathology to discriminate between different species. This diagnostic gap precludes the optimal use of antifungals, leading to adverse patient outcomes. The identification of fungal pathogens from Formalin-fixed, Paraffin-embedded tissue (FFPE) blocks by molecular methods is emerging as an alternative approach to study the etiology of IFI. PCR assays, including species specific- and broadrange fungal tests are used with FFPE samples from patients with proven IFI. Fungal species identification is achieved in 15-90% of the samples. This heterogeneity may be explained by the samples studied. However, comparison of different studies is impaired, as controls ruling out false positive-, false negative test results or PCR inhibition are frequently not reported. Studies using in situ hybridization also vary in the clinical samples included and the targeted fungi. In addition, target sequences, the probe chemistry and the detection of hybridization signals also account for the differences in diagnostic sensitivity. Using both approaches in parallel yields additive insights, potentially leading to a superior identification of fungal etiology and awareness of the limitations of both molecular diagnostic approaches.
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Affiliation(s)
- Volker Rickerts
- Robert Koch Institut, FG 16, Nordufer 20, 13353 Berlin, Germany.
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31
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Kanamori H, Rutala WA, Sickbert-Bennett EE, Weber DJ. Review of Fungal Outbreaks and Infection Prevention in Healthcare Settings During Construction and Renovation. Clin Infect Dis 2015; 61:433-44. [DOI: 10.1093/cid/civ297] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 04/04/2015] [Indexed: 01/08/2023] Open
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32
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Molecular and nonmolecular diagnostic methods for invasive fungal infections. Clin Microbiol Rev 2015; 27:490-526. [PMID: 24982319 DOI: 10.1128/cmr.00091-13] [Citation(s) in RCA: 207] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Invasive fungal infections constitute a serious threat to an ever-growing population of immunocompromised individuals and other individuals at risk. Traditional diagnostic methods, such as histopathology and culture, which are still considered the gold standards, have low sensitivity, which underscores the need for the development of new means of detecting fungal infectious agents. Indeed, novel serologic and molecular techniques have been developed and are currently under clinical evaluation. Tests like the galactomannan antigen test for aspergillosis and the β-glucan test for invasive Candida spp. and molds, as well as other antigen and antibody tests, for Cryptococcus spp., Pneumocystis spp., and dimorphic fungi, have already been established as important diagnostic approaches and are implemented in routine clinical practice. On the other hand, PCR and other molecular approaches, such as matrix-assisted laser desorption ionization (MALDI) and fluorescence in situ hybridization (FISH), have proved promising in clinical trials but still need to undergo standardization before their clinical use can become widespread. The purpose of this review is to highlight the different diagnostic approaches that are currently utilized or under development for invasive fungal infections and to identify their performance characteristics and the challenges associated with their use.
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Abstract
PURPOSE OF REVIEW Novel treatment modalities for previously fatal diseases, including newer chemotherapeutic and biologic agents and the expansion of the indications for solid organ and stem cell transplantation, have resulted in prolonged patient survival and a significant increase in the population of immunocompromised hosts (ICHs). RECENT FINDINGS This review discusses the increasing spectrum of opportunistic infections in the ICH, the general approach for early diagnosis and treatment of pulmonary infections in this population, and the current and novel diagnostic modalities available to establish a rapid and specific microbiologic diagnosis, focusing on recent controversies and advances. SUMMARY Early diagnosis and prompt initiation of effective therapy for infection help reduce morbidity in ICHs. Advances in diagnostic assays using nonculture-based methods, such as nucleic acid amplification, may allow for earlier targeted therapy. Invasive procedures including bronchoscopy and biopsy remain essential and should be vigorously pursued in ICHs given the broad differential diagnosis of possible pulmonary pathogens in this population, and the need to establish a specific diagnosis to allow accurate targeted therapy.
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Lorenz MG, Mühl H, Disqué C. Bacterial and fungal DNA extraction from blood samples: manual protocols. Methods Mol Biol 2015; 1237:109-119. [PMID: 25319784 DOI: 10.1007/978-1-4939-1776-1_11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A critical point of molecular diagnosis of systemic infections is the method employed for the extraction of microbial DNA from blood. A DNA isolation method has to be able to fulfill several fundamental requirements for optimal performance of diagnostic assays. First of all, low- and high-molecular-weight substances of the blood inhibitory to downstream analytical reactions like PCR amplification have to be removed. This includes human DNA which is a known source of false-positive results and factor decreasing the analytical sensitivity of PCR assays by unspecific primer binding. At the same time, even extremely low amounts of microbial DNA need to be supplied to molecular diagnostic assays in order to detect low pathogen loads in the blood. Further, considering the variety of microbial etiologies of sepsis, a method should be capable of lysing Gram-positive, Gram-negative, and fungal organisms. Last, extraction buffers, reagents, and consumables have to be free of microbial DNA which leads to false-positive results. Here, we describe manual methods which allow the extraction of microbial DNA from small- and large-volume blood samples for the direct molecular analysis of pathogen.
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Affiliation(s)
- Michael G Lorenz
- Molzym GmbH & Co. KG, Mary-Astell-Straße 10, Bremen, 28359, Germany,
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Koo S, Thomas HR, Daniels SD, Lynch RC, Fortier SM, Shea MM, Rearden P, Comolli JC, Baden LR, Marty FM. A breath fungal secondary metabolite signature to diagnose invasive aspergillosis. Clin Infect Dis 2014; 59:1733-40. [PMID: 25342502 DOI: 10.1093/cid/ciu725] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Invasive aspergillosis (IA) remains a leading cause of mortality in immunocompromised patients, in part due to the difficulty of diagnosing this infection. METHODS Using thermal desorption-gas chromatography/mass spectrometry, we characterized the in vitro volatile metabolite profile of Aspergillus fumigatus, the most common cause of IA, and other pathogenic aspergilli. We prospectively collected breath samples from patients with suspected invasive fungal pneumonia from 2011 to 2013, and assessed whether we could discriminate patients with proven or probable IA from patients without aspergillosis, as determined by European Organization for Research and Treatment of Cancer/Mycoses Study Group consensus definitions, by direct detection of fungal volatile metabolites in these breath samples. RESULTS The monoterpenes camphene, α- and β-pinene, and limonene, and the sesquiterpene compounds α- and β-trans-bergamotene were distinctive volatile metabolites of A. fumigatus in vitro, distinguishing it from other pathogenic aspergilli. Of 64 patients with suspected invasive fungal pneumonia based on host risk factors, clinical symptoms, and radiologic findings, 34 were diagnosed with IA, whereas 30 were ultimately diagnosed with other causes of pneumonia, including other invasive mycoses. Detection of α-trans-bergamotene, β-trans-bergamotene, a β-vatirenene-like sesquiterpene, or trans-geranylacetone identified IA patients with 94% sensitivity (95% confidence interval [CI], 81%-98%) and 93% specificity (95% CI, 79%-98%). CONCLUSIONS In patients with suspected fungal pneumonia, an Aspergillus secondary metabolite signature in breath can identify individuals with IA. These results provide proof-of-concept that direct detection of exogenous fungal metabolites in breath can be used as a novel, noninvasive, pathogen-specific approach to identifying the precise microbial cause of pneumonia.
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Affiliation(s)
- Sophia Koo
- Division of Infectious Diseases, Brigham and Women's Hospital Dana-Farber Cancer Institute Harvard Medical School, Boston
| | - Horatio R Thomas
- Division of Infectious Diseases, Brigham and Women's Hospital Harvard Medical School, Boston
| | - S David Daniels
- Division of Infectious Diseases, Brigham and Women's Hospital
| | - Robert C Lynch
- Division of Infectious Diseases, Brigham and Women's Hospital
| | - Sean M Fortier
- Division of Infectious Diseases, Brigham and Women's Hospital
| | - Margaret M Shea
- Division of Infectious Diseases, Brigham and Women's Hospital
| | | | | | - Lindsey R Baden
- Division of Infectious Diseases, Brigham and Women's Hospital Dana-Farber Cancer Institute Harvard Medical School, Boston
| | - Francisco M Marty
- Division of Infectious Diseases, Brigham and Women's Hospital Dana-Farber Cancer Institute Harvard Medical School, Boston
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Fungal DNA detected in blood samples of patients who received contaminated methylprednisolone injections reveals increased complexity of causative agents. J Clin Microbiol 2014; 52:2212-5. [PMID: 24719442 DOI: 10.1128/jcm.00854-14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Using Exserohilum rostratum-specific and panfungal real-time PCR, we studied 24 blood samples and 2 synovial fluid specimens from 20 patients with persistent or worsening pain following injections of contaminated methylprednisolone. Seven blood specimens from 6 patients were significantly positive for fungal DNA by panfungal PCR, with multiple fungal species identified.
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38
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Zhang SX. Enhancing molecular approaches for diagnosis of fungal infections. Future Microbiol 2013; 8:1599-611. [DOI: 10.2217/fmb.13.120] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Molecular tests can improve the diagnosis of fungal infections. Despite the increasing application for fungal detection, molecular tests are still not accepted as a diagnostic criterion to define invasive fungal diseases. This limitation is largely due to a lack of a standardized method. Method standardization can be achieved by following a consensus protocol developed by a working group, by performing a molecular test in a centralized laboratory or by using a commercial assay that provides a standardized method and quality-controlled reagents. Forming a consortium or a working group consisting of large-scale diagnostic mycology laboratories can accelerate the process of validating and implementing a commercial molecular assay for clinical use through a joint effort between industry partners and clinicians. Development of molecular tests not only for the detection of fungi but also for the identification of antifungal drug resistance directly in blood, bronchoalveolar lavage fluid, cerebrospinal fluid, and formalin-fixed and paraffin-embedded tissues greatly enhances fungal diagnostic capacities. Advances of developing quantitative assays and RNA detection platforms may provide another avenue to further improve fungal diagnostics.
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Affiliation(s)
- Sean X Zhang
- Division of Medical Microbiology, Department of Pathology, Johns Hopkins University School of Medicine, Johns Hopkins Hospital, 600 Wolfe Street, Meyer B1-193, Baltimore 21287, MD, USA
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Gómez BL. Molecular diagnosis of endemic and invasive mycoses: advances and challenges. Rev Iberoam Micol 2013; 31:35-41. [PMID: 24252827 DOI: 10.1016/j.riam.2013.09.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 09/27/2013] [Indexed: 10/26/2022] Open
Abstract
The diagnosis of endemic and invasive fungal disease remains challenging. Molecular techniques for identification of fungi now play a significant and growing role in clinical mycology and offer distinct advantages as they are faster, more sensitive and more specific. The aim of this mini-review is to provide an overview of the state of the art of molecular diagnosis of endemic and invasive fungal diseases, and to emphasize the challenges and current need for standardization of the different methods. The European Aspergillus PCR Initiative (EAPCRI) has made significant progress in developing a standard for Aspergillus polymerase chain reaction (PCR), but recognizes that the process will not be finished until clinical utility has been established in formal and extensive clinical trials. Similar efforts should be implemented for the diagnosis of the other mycoses in order to fully validate the current methods or reinforce the need to design new ones. This manuscript is part of the series of works presented at the "V International Workshop: Molecular genetic approaches to the study of human pathogenic fungi" (Oaxaca, Mexico, 2012).
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Affiliation(s)
- Beatriz L Gómez
- School of Medicine and Health Sciences, Universidad del Rosario, Bogota, Colombia; Medical and Experimental Mycology Group, Corporación para Investigaciones Biológicas (CIB), Medellin, Colombia.
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40
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Riwes MM, Wingard JR. Diagnostic methods for invasive fungal diseases in patients with hematologic malignancies. Expert Rev Hematol 2013; 5:661-9. [PMID: 23216596 DOI: 10.1586/ehm.12.53] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Invasive fungal disease is associated with increased morbidity and mortality in hematologic malignancy patients and hematopoietic stem cell transplant recipients. Timely recognition and treatment of invasive fungal diseases in these patients are essential and decrease mortality. However, conventional definitive diagnostic methods are difficult and time consuming. While conventional microbiological and histopathological methods are still needed for a definitive diagnosis of invasive fungal disease, new noninvasive diagnostic methods including serologic and molecular biomarkers are now available. These new diagnostic methods facilitate an early diagnosis of invasive fungal disease and allow for utilization of a pre-emptive treatment approach, which may ultimately lead to improved treatment outcomes and reduced toxicity.
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Affiliation(s)
- Mary Mansour Riwes
- University of Florida, College of Medicine, Division of Hematology/Oncology 1600 W Archer Road, Gainesville, FL 32610-0278, USA
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Rickerts V, McCormick Smith I, Mousset S, Kommedal O, Fredricks DN. Deciphering the aetiology of a mixed fungal infection by broad-range PCR with sequencing and fluorescence in situ hybridisation. Mycoses 2013; 56:681-6. [PMID: 23560622 DOI: 10.1111/myc.12083] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 03/18/2013] [Accepted: 03/21/2013] [Indexed: 11/30/2022]
Abstract
Simultaneous infections with multiple fungi may be misinterpreted as monomicrobial infections by current diagnostics with ramifications for the choice of antimicrobial agents that may impact patient outcomes. The application of molecular methods on tissue samples may be useful to decipher the aetiology of mixed fungal infections. We present a leukaemic patient who died from sepsis due to candidaemia. The postmortem examination documented fungal elements in lung tissue. Fungal DNA was amplified from the lung sample by broad-range PCR assays targeting the 28S ribosomal RNA gene or the internal transcribed spacer 2 (ITS-2). Fluorescence in situ hybridisation (FISH) using differentially labelled fungal probes was applied on the tissue. Sequencing identified the PCR amplicons as Aspergillus fumigatus (28S assay) and Candida tropicalis (ITS-2 assay). As a chromatogram suggested mixed amplicons, the Isentio ripseq(®) tool for in silico analysis was applied and confirmed the presence of both amplicons in the PCR products of both assays. FISH confirmed the presence of Aspergillus and Candida within the infectious process, a prerequisite for inferring a causal relationship with the infection. The combination of broad-range PCR with sequence analysis and FISH applied on tissue samples is a powerful approach to identify the aetiology of invasive fungal infections, including mixed infections.
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Affiliation(s)
- V Rickerts
- Robert Koch Institut, FG 16, Berlin, Germany
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Zhao Y, Stensvold CR, Perlin DS, Arendrup MC. Azole resistance in Aspergillus fumigatus from bronchoalveolar lavage fluid samples of patients with chronic diseases. J Antimicrob Chemother 2013; 68:1497-504. [PMID: 23463213 DOI: 10.1093/jac/dkt071] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES Triazole resistance in Aspergillus fumigatus has been increasing. We explored the A. fumigatus azole resistance profiles in bronchoalveolar lavage (BAL) fluid samples from Danish patients examined for aspergillosis. METHODS A total of 94 BAL samples from 87 patients were evaluated by galactomannan (GM) test and A. fumigatus CYP51A profiling by PCR. RESULTS Aspergillus spp. were isolated from 27/48 (56.3%) cultured samples, including 23 A. fumigatus with one resistant strain (4.3%). Samples were classified into GM-positive (≥3.0), GM-intermediate (0.5 to <3.0) and GM-negative (<0.5) groups, where the CYP51A PCR was positive in 81.8% (36/44), 56.3% (18/32) and 38.9% (7/18) of samples, respectively. Nine CYP51A PCR-positive samples (9/61, 14.8%) were found to have mutations resulting in amino acid substitutions. M220V was detected from a sample culture positive for susceptible A. fumigatus and P216L was found in a culture-negative BAL sample. Conversely, no mutation was found in one sample culture positive for azole-resistant A. fumigatus. The tandem repeat/L98H mutation was not detected. CONCLUSIONS Our study shows that azole resistance in A. fumigatus can be cryptic and may go undiagnosed. The combination of improved culture/susceptibility tests and the direct molecular detection of resistance markers will facilitate prompt institution of appropriate antifungal therapy.
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Affiliation(s)
- Yanan Zhao
- Public Health Research Institute Center, UMDNJ-NJMS, Newark, NJ 07103, USA
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43
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Lewis White P, Loeffler J, Barnes RA, Peter Donnelly J. Towards a standard for Aspergillus PCR - requirements, process and results. INFECTIO 2012. [DOI: 10.1016/s0123-9392(12)70029-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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44
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Morton CO, de Luca A, Romani L, Rogers TR. RT-qPCR detection of Aspergillus fumigatus RNA in vitro and in a murine model of invasive aspergillosis utilizing the PAXgene® and Tempus™ RNA stabilization systems. Med Mycol 2012; 50:661-6. [PMID: 22263641 DOI: 10.3109/13693786.2011.652200] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Molecular diagnosis of invasive aspergillosis (IA) is a potentially life-saving tool in the care of at-risk individuals. To date, the development of PCR-based diagnostic tests has been hampered by the lack of standardization in the methods for such critical activities. In this study, we used both spiked volunteer blood samples and a murine model of IA to test the utility of the PAXgene and Tempus systems for stabilization and isolation of fungal RNA from blood as part of an evaluation of a new diagnostic strategy. In spiking experiments, RNA isolation followed by RT-qPCR that targeted the 18S gene was compared to a standard DNA isolation and qPCR assay that targeted the ITS ribosomal region. We demonstrated that both PAXgene and Tempus RNA stabilization and extraction systems followed by RT-qPCR had similar performance in detecting fungal RNA in blood samples from Aspergillus fumigates-infected mice. In spiked samples, the Tempus system performed better than the PAXgene system as it detected 100% of all samples spiked with 10 or 20 germinated Aspergillus conidia/ml blood sample as compared to the PAXgene system which detected 33% and 56% of the samples spiked with 10 or 20 conidia/ml, respectively. The stabilization of fungal nucleic acids in blood samples and its efficient isolation by a commercial method is an important step in the development of standardized molecular diagnostic tools that are needed to improve the outcomes for individuals with IA.
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Affiliation(s)
- Charles Oliver Morton
- Department of Clinical Microbiology, Sir Patrick Dun Research Laboratory, Trinity College Dublin, St James's Hospital, Dublin, Ireland.
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45
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Fricke S, Fricke C, Oelkrug C, Blatz R, Schönfelder U, Niederwieser D, Hilger N, Ruhnke M, Rodloff AC. A real-time PCR for the detection and characterisation of Aspergillus species. Mycoses 2011; 55:416-25. [PMID: 22151280 DOI: 10.1111/j.1439-0507.2011.02161.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An early diagnosis of an invasive fungal infection is essential for the initiation of a specific antifungal therapy and to avoid unnecessary discontinuation of a baseline therapy for haematological or oncological diseases. A real-time PCR assay for the detection and strain identification of Aspergillus species from culture strains was evaluated. DNA preparation was evaluated in contaminated culture media, urine and serum. A LightCycler PCR to differentiate various Aspergillus species was established. A real-time PCR assay for the detection of Aspergillus species was improved and was able to detect and differentiate medically important Aspergillus spp. The sensitivity of the test was <10 plasmid equivalents/assay. The real-time PCR assay is a useful tool for the rapid identification of Aspergillus species and might be useful as an early diagnostic tool to detect an invasive fungal infection. A real-time PCR protocol was improved by generating plasmid standards, additional generation of melting curves for species identification and the correlation between the melting temperature and the nucleotide exchanges within the used 18S rRNA gene region.
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Affiliation(s)
- Stephan Fricke
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Leipzig, Germany.
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46
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Abstract
Fungal pneumonia is increasingly common, particularly in highly immunosuppressed patients, such as solid organ or hematopoietic stem cell transplant recipients, and the diagnosis is evolving. Although standard techniques such as microscopy and culture remain the mainstays of diagnosis, relatively recent advances in serological and molecular testing are important additions to the field. This article reviews the laboratory tools used to diagnose fungal respiratory disease.
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Affiliation(s)
- Erika D Lease
- Department of Medicine, Division of Infectious Diseases and International Health, Duke University Medical Center, Durham, North Carolina 27710, USA
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47
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Lass-Flörl C, Follett S, Moody A, Denning D. Detection ofAspergillusin lung and other tissue samples using the MycAssay Aspergillus real-time PCR kit. Can J Microbiol 2011; 57:765-8. [DOI: 10.1139/w11-064] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- C. Lass-Flörl
- Division of Hygiene and Medical Microbiology, Innsbruck Medical University, Fritz-Pregl-Straße 3, 6020 Innsbruck, Austria
| | - S.A. Follett
- Myconostica Ltd., South Court, Sharston Road, Manchester, M22 4SN, UK
| | - A. Moody
- Myconostica Ltd., South Court, Sharston Road, Manchester, M22 4SN, UK
| | - D.W. Denning
- Myconostica Ltd., South Court, Sharston Road, Manchester, M22 4SN, UK
- National Aspergillosis Centre, University Hospital of South Manchester, University of Manchester, Manchester Academic Health Science Centre, Southmoor Road, Manchester, M23 9LT, UK
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48
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Morton CO, Clemons KV, Springer J, Mueller JG, Rogers TR, Stevens DA, Kurzai O, Einsele H, Loeffler J. Real-time PCR and quantitative culture for monitoring of experimental Aspergillus fumigatus intracranial infection in neutropenic mice. J Med Microbiol 2011; 60:913-919. [PMID: 21436369 DOI: 10.1099/jmm.0.028399-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The central nervous system (CNS) is the most common site of dissemination during Aspergillus infection. PCR has the potential to facilitate early diagnosis of CNS aspergillosis, which could assist in reducing disease mortality. In two experiments, neutropenic CD-1 male mice were infected intracranially with 5×10⁶ conidia of Aspergillus fumigatus. At time points up to 120 h after infection, mice were euthanized and samples of blood, brain, spinal cord and cerebrospinal fluid (CSF) were taken. The brain fungal burden was determined by quantitative culture, and fungal DNA was detected by quantitative PCR. Plating for A. fumigatus from the brain confirmed that all mice had burdens of log₁₀>3 from 4 to 120 h after infection. A. fumigatus DNA was detected in blood (88 %), brain (96 %), CSF (52 %) and spinal cord (92 %) samples. The brain and spinal cord contained the highest concentrations of fungal DNA. Adapting the extraction protocol to maximize yield from small sample volumes (10 µl CSF or 200 µl blood) allowed PCR detection of A. fumigatus in infected mice, suggesting the use of CSF and blood as diagnostic clinical samples for CNS aspergillosis.
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Affiliation(s)
- C Oliver Morton
- Department of Clinical Microbiology, Sir Patrick Dun Research Laboratory, School of Medicine, Trinity College Dublin, Dublin 8, Ireland
| | - Karl V Clemons
- California Institute for Medical Research, San Jose, CA 95128, USA.,Department of Medicine, Division of Infectious Diseases and Geographic Medicine, Stanford University, Stanford, CA 94305, USA.,Department of Medicine, Division of Infectious Diseases, Santa Clara Valley Medical Center, San Jose, CA 95128-2699, USA
| | - Jan Springer
- Universität Wuerzburg, Medizinische Klinik & Poliklinik II, Wuerzburg, Germany
| | - Justus G Mueller
- Pathologisches Institut der Universität Wuerzburg, Wuerzburg, Germany
| | - Thomas R Rogers
- Department of Clinical Microbiology, Sir Patrick Dun Research Laboratory, School of Medicine, Trinity College Dublin, Dublin 8, Ireland
| | - David A Stevens
- Department of Medicine, Division of Infectious Diseases and Geographic Medicine, Stanford University, Stanford, CA 94305, USA.,Department of Medicine, Division of Infectious Diseases, Santa Clara Valley Medical Center, San Jose, CA 95128-2699, USA.,California Institute for Medical Research, San Jose, CA 95128, USA
| | - Oliver Kurzai
- Friedrich-Schiller-Universität Jena, Septomics Research Centre, Leibniz Institute for Natural Products Research and Infection Biology - Hans Knöll Institute, Jena, Germany
| | - Hermann Einsele
- Universität Wuerzburg, Medizinische Klinik & Poliklinik II, Wuerzburg, Germany
| | - Juergen Loeffler
- Universität Wuerzburg, Medizinische Klinik & Poliklinik II, Wuerzburg, Germany
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