1
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The role of Nucleic Acid Mimics (NAMs) on FISH-based techniques and applications for microbial detection. Microbiol Res 2022; 262:127086. [PMID: 35700584 DOI: 10.1016/j.micres.2022.127086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 06/01/2022] [Accepted: 06/03/2022] [Indexed: 01/07/2023]
Abstract
Fluorescent in situ hybridization (FISH) is a powerful tool that for more than 30 years has allowed to detect and quantify microorganisms as well as to study their spatial distribution in three-dimensional structured environments such as biofilms. Throughout these years, FISH has been improved in order to face some of its earlier limitations and to adapt to new research objectives. One of these improvements is related to the emergence of Nucleic Acid Mimics (NAMs), which are now employed as alternatives to the DNA and RNA probes that have been classically used in FISH. NAMs such as peptide and locked nucleic acids (PNA and LNA) have provided enhanced sensitivity and specificity to the FISH technique, as well as higher flexibility in terms of applications. In this review, we aim to cover the state-of-the-art of the different NAMs and explore their possible applications in FISH, providing a general overview of the technique advancement in the last decades.
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2
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Identification of Pneumocystis jirovecii with Fluorescence In-Situ Hybridization (FISH) in Patient Samples-A Proof-of-Principle. J Fungi (Basel) 2021; 8:jof8010013. [PMID: 35049953 PMCID: PMC8778293 DOI: 10.3390/jof8010013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 12/21/2021] [Accepted: 12/23/2021] [Indexed: 11/17/2022] Open
Abstract
In resource-limited settings, where pneumocystosis in immunocompromised patients is infrequently observed, cost-efficient, reliable, and sensitive approaches for the diagnostic identification of Pneumocystis jirovecii in human tissue samples are desirable. Here, an in-house fluorescence in situ hybridization assay was comparatively evaluated against Grocott’s staining as a reference standard with 30 paraffin-embedded tissue samples as well as against in-house real-time PCR with 30 respiratory secretions from immunocompromised patients with clinical suspicion of pneumocystosis. All pneumocystosis patients included in the study suffered from HIV/AIDS. Compared with Grocott’s staining as the reference standard, sensitivity of the FISH assay was 100% (13/13), specificity was 41% (7/17), and the overall concordance was 66.7% with tissue samples. With respiratory specimens, sensitivity was 83.3% (10/12), specificity was 100% (18/18), and the overall concordance was 93.3% as compared with real-time PCR. It remained unresolved to which proportions sensitivity limitations of Grocott’s staining or autofluorescence phenomena affecting the FISH assay accounted for the recorded reduced specificity with the tissue samples. The assessment confirmed Pneumocystis FISH in lung tissue as a highly sensitive screening approach; however, dissatisfying specificity in paraffin-embedded biopsies calls for confirmatory testing with other techniques in case of positive FISH screening results. In respiratory secretions, acceptable sensitivity and excellent specificity were demonstrated for the diagnostic application of the P. jirovecii-specific FISH assay.
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3
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Brodyagin N, Katkevics M, Kotikam V, Ryan CA, Rozners E. Chemical approaches to discover the full potential of peptide nucleic acids in biomedical applications. Beilstein J Org Chem 2021; 17:1641-1688. [PMID: 34367346 PMCID: PMC8313981 DOI: 10.3762/bjoc.17.116] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 06/28/2021] [Indexed: 12/23/2022] Open
Abstract
Peptide nucleic acid (PNA) is arguably one of the most successful DNA mimics, despite a most dramatic departure from the native structure of DNA. The present review summarizes 30 years of research on PNA's chemistry, optimization of structure and function, applications as probes and diagnostics, and attempts to develop new PNA therapeutics. The discussion starts with a brief review of PNA's binding modes and structural features, followed by the most impactful chemical modifications, PNA enabled assays and diagnostics, and discussion of the current state of development of PNA therapeutics. While many modifications have improved on PNA's binding affinity and specificity, solubility and other biophysical properties, the original PNA is still most frequently used in diagnostic and other in vitro applications. Development of therapeutics and other in vivo applications of PNA has notably lagged behind and is still limited by insufficient bioavailability and difficulties with tissue specific delivery. Relatively high doses are required to overcome poor cellular uptake and endosomal entrapment, which increases the risk of toxicity. These limitations remain unsolved problems waiting for innovative chemistry and biology to unlock the full potential of PNA in biomedical applications.
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Affiliation(s)
- Nikita Brodyagin
- Department of Chemistry, Binghamton University, The State University of New York, Binghamton, New York 13902, United States
| | - Martins Katkevics
- Latvian Institute of Organic Synthesis, Aizkraukles 21, Riga, LV-1006, Latvia
| | - Venubabu Kotikam
- Department of Chemistry, Binghamton University, The State University of New York, Binghamton, New York 13902, United States
| | - Christopher A Ryan
- Department of Chemistry, Binghamton University, The State University of New York, Binghamton, New York 13902, United States
| | - Eriks Rozners
- Department of Chemistry, Binghamton University, The State University of New York, Binghamton, New York 13902, United States
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4
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Abstract
Invasive candidiasis (IC) is a collective term that refers to a group of infectious syndromes caused by a variety of species of Candida, 6 of which cause most cases globally. Candidemia is probably the most commonly recognized syndrome associated with IC; however, Candida can cause invasive infection of any organ, especially visceral organs, vasculature, bones and joints, the eyes and central nervous system. Targeted prevention and empirical therapy are important interventions for patients at high risk for IC, and the current approach should be based on a combination of clinical risk factors and non-culture-based diagnostics, when available.
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Affiliation(s)
- Todd P McCarty
- University of Alabama at Birmingham, Birmingham VA Medical Center, 1900 University Boulevard, THT 229, Birmingham, AL 35294, USA.
| | - Cameron M White
- University of Alabama at Birmingham, 1900 University Boulevard, THT 229, Birmingham, AL 35294, USA
| | - Peter G Pappas
- University of Alabama at Birmingham, 1900 University Boulevard, THT 229, Birmingham, AL 35294, USA
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5
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Zhao C, Mendive-Tapia L, Vendrell M. Fluorescent peptides for imaging of fungal cells. Arch Biochem Biophys 2018; 661:187-195. [PMID: 30465736 DOI: 10.1016/j.abb.2018.11.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 11/06/2018] [Accepted: 11/16/2018] [Indexed: 12/17/2022]
Abstract
Fungal infections, especially with the advent of antimicrobial resistance, represent a major burden to our society. As a result, there has been an increasing interest in the development of new probes that accelerate the study of fungi-related biological processes and facilitate novel clinical diagnostic and treatment strategies. Fluorescence-based reporters can provide dynamic information at the molecular level with high spatial resolution. However, conventional fluorescent probes for microbes often suffer from low specificity. In the last decade, numerous studies have been reported on the chemical design and application of fluorescent peptides for both in vitro and in vivo imaging of fungal cells. In this article, we review different strategies used in the preparation of fluorescent peptides for pathogenic fungi as well as some of their applications in medical imaging and in mode-of-action mechanistic studies.
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Affiliation(s)
- Can Zhao
- Manchester Fungal Infection Group, Division of Infection, Immunity and Respiratory Medicine, University of Manchester, Manchester, M13 9NT, United Kingdom
| | - Lorena Mendive-Tapia
- Centre for Inflammation Research, The University of Edinburgh, Edinburgh, EH16 4TJ, United Kingdom
| | - Marc Vendrell
- Centre for Inflammation Research, The University of Edinburgh, Edinburgh, EH16 4TJ, United Kingdom.
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Multicenter Evaluation of the Accelerate PhenoTest BC Kit for Rapid Identification and Phenotypic Antimicrobial Susceptibility Testing Using Morphokinetic Cellular Analysis. J Clin Microbiol 2018; 56:JCM.01329-17. [PMID: 29305546 PMCID: PMC5869823 DOI: 10.1128/jcm.01329-17] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 12/19/2017] [Indexed: 12/29/2022] Open
Abstract
We describe results from a multicenter study evaluating the Accelerate Pheno system, a first of its kind diagnostic system that rapidly identifies common bloodstream pathogens from positive blood cultures within 90 min and determines bacterial phenotypic antimicrobial susceptibility testing (AST) results within ∼7 h. A combination of fresh clinical and seeded blood cultures were tested, and results from the Accelerate Pheno system were compared to Vitek 2 results for identification (ID) and broth microdilution or disk diffusion for AST. The Accelerate Pheno system accurately identified 14 common bacterial pathogens and two Candida spp. with sensitivities ranging from 94.6 to 100%. Of fresh positive blood cultures, 89% received a monomicrobial call with a positive predictive value of 97.3%. Six common Gram-positive cocci were evaluated for ID. Five were tested against eight antibiotics, two resistance phenotypes (methicillin-resistant Staphylococcus aureus and Staphylococcus spp. [MRSA/MRS]), and inducible clindamycin resistance (MLSb). From the 4,142 AST results, the overall essential agreement (EA) and categorical agreement (CA) were 97.6% and 97.9%, respectively. Overall very major error (VME), major error (ME), and minor error (mE) rates were 1.0%, 0.7%, and 1.3%, respectively. Eight species of Gram-negative rods were evaluated against 15 antibiotics. From the 6,331 AST results, overall EA and CA were 95.4% and 94.3%, respectively. Overall VME, ME, and mE rates were 0.5%, 0.9%, and 4.8%, respectively. The Accelerate Pheno system has the unique ability to identify and provide phenotypic MIC and categorical AST results in a few hours directly from positive blood culture bottles and support accurate antimicrobial adjustment.
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Müller V, Sousa JM, Ceylan Koydemir H, Veli M, Tseng D, Cerqueira L, Ozcan A, Azevedo NF, Westerlund F. Identification of pathogenic bacteria in complex samples using a smartphone based fluorescence microscope. RSC Adv 2018; 8:36493-36502. [PMID: 35558922 PMCID: PMC9088845 DOI: 10.1039/c8ra06473c] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 10/21/2018] [Indexed: 11/21/2022] Open
Abstract
Diagnostics based on fluorescence imaging of biomolecules is typically performed in well-equipped laboratories and is in general not suitable for remote and resource limited settings. Here we demonstrate the development of a compact, lightweight and cost-effective smartphone-based fluorescence microscope, capable of detecting signals from fluorescently labeled bacteria. By optimizing a peptide nucleic acid (PNA) based fluorescence in situ hybridization (FISH) assay, we demonstrate the use of the smartphone-based microscope for rapid identification of pathogenic bacteria. We evaluated the use of both a general nucleic acid stain as well as species-specific PNA probes and demonstrated that the mobile platform can detect bacteria with a sensitivity comparable to that of a conventional fluorescence microscope. The PNA-based FISH assay, in combination with the smartphone-based fluorescence microscope, allowed us to qualitatively analyze pathogenic bacteria in contaminated powdered infant formula (PIF) at initial concentrations prior to cultivation as low as 10 CFU per 30 g of PIF. Importantly, the detection can be done directly on the smartphone screen, without the need for additional image analysis. The assay should be straightforward to adapt for bacterial identification also in clinical samples. The cost-effectiveness, field-portability and simplicity of this platform will create various opportunities for its use in resource limited settings and point-of-care offices, opening up a myriad of additional applications based on other fluorescence-based diagnostic assays. A smartphone-based fluorescence microscope for detection of bacteria in complex samples using a species-specific peptide nucleic acid probe.![]()
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Affiliation(s)
- Vilhelm Müller
- Department of Biology and Biological Engineering
- Chalmers University of Technology
- Gothenburg
- Sweden
| | | | - Hatice Ceylan Koydemir
- Electrical and Computer Engineering Department
- University of California
- Los Angeles
- USA
- Bioengineering Department
| | - Muhammed Veli
- Electrical and Computer Engineering Department
- University of California
- Los Angeles
- USA
- Bioengineering Department
| | - Derek Tseng
- Electrical and Computer Engineering Department
- University of California
- Los Angeles
- USA
- Bioengineering Department
| | | | - Aydogan Ozcan
- Electrical and Computer Engineering Department
- University of California
- Los Angeles
- USA
- Bioengineering Department
| | - Nuno F. Azevedo
- LEPABE
- Department of Chemical Engineering
- Faculty of Engineering of the University of Porto
- 4200-465 Porto
- Portugal
| | - Fredrik Westerlund
- Department of Biology and Biological Engineering
- Chalmers University of Technology
- Gothenburg
- Sweden
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8
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Maubon D, Dard C, Garnaud C, Cornet M. Profile of GenMark's ePlex® blood culture identification fungal pathogen panel. Expert Rev Mol Diagn 2017; 18:119-132. [PMID: 29284316 DOI: 10.1080/14737159.2018.1420476] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
INTRODUCTION Fungemia presents high morbi-mortality and thus rapid microbiological diagnosis may contribute to appropriate patient management. In the last decade, kits based on molecular technologies have become available and health care institutes are increasingly facing critical investment choices. Although all these tools aim to achieve rapid fungal detection and species identification, they display different inherent characteristics. Areas covered: Considering technologies allowing detection and identification of fungal species in a sepsis context, the market proposes either tests on positive blood culture or tests on patient's whole blood. In this review, the authors describe and compare the ePlex® Blood Culture Identification Fungal Pathogen (BCID-FP) test, a fully automated one-step single-use cartridge assay that has been designed to detect identify frequent or rare but emerging, fungal species, from positive blood culture. A comparison with the competing kits is provided. Expert commentaries: The ePlex BCID-FP test provides a diversified and rather relevant panel. Its easy-to-use cartridges allow flexible use around the clock. Nevertheless, prospective clinical studies assessing the time-to-result benefit on antifungal stewardship and on hospital length of stay are not available yet. New tools aim to benefit clinicians and patients, but they should be accompanied by supervision of result interpretation and adaptation of antifungal stewardship.
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Affiliation(s)
- Danièle Maubon
- a Univsité Grenoble Alpes, CNRS, Grenoble INP*, TIMC-IMAG , Grenoble , France.,b Parasitology-Mycology Laboratory, Infectious Agents Department , CHU Grenoble-Alpes , Grenoble , France
| | - Céline Dard
- b Parasitology-Mycology Laboratory, Infectious Agents Department , CHU Grenoble-Alpes , Grenoble , France
| | - Cécile Garnaud
- a Univsité Grenoble Alpes, CNRS, Grenoble INP*, TIMC-IMAG , Grenoble , France.,b Parasitology-Mycology Laboratory, Infectious Agents Department , CHU Grenoble-Alpes , Grenoble , France
| | - Muriel Cornet
- a Univsité Grenoble Alpes, CNRS, Grenoble INP*, TIMC-IMAG , Grenoble , France.,b Parasitology-Mycology Laboratory, Infectious Agents Department , CHU Grenoble-Alpes , Grenoble , France
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9
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Abstract
Bacteremia and sepsis are conditions associated with high mortality and are of great impact to health care operations. Among the top causes of mortality in the United States, these conditions cause over 600 fatalities each day. Empiric, broad-spectrum treatment is a common but often a costly approach that may fail to effectively target the correct microbe, may inadvertently harm patients via antimicrobial toxicity or downstream antimicrobial resistance. To meet the diagnostic challenges of bacteremia and sepsis, laboratories must understand the complexity of diagnosing and treating septic patients, in order to focus on creating algorithms that can help direct a more targeted approach to antimicrobial therapy and synergize with existing clinical practices defined in new Surviving Sepsis Guidelines. Significant advances have been made in improving blood culture media; as yet no molecular or antigen-based method has proven superior for the detection of bacteremia in terms of limit of detection. Several methods for rapid molecular identification of pathogens from blood cultures bottles are available and many more are on the diagnostic horizon. Ultimately, early intervention by molecular detection of bacteria and fungi directly from whole blood could provide the most patient benefit and contribute to tailored antibiotic coverage of the patient early on in the course of the disease. Although blood cultures remain as the best means of diagnosing bacteremia and candidemia, complementary testing with antigen tests, microbiologic investigations from other body sites, and histopathology can often aid in the diagnosis of disseminated disease, and application of emerging nucleic acid test methods and other new technology may greatly impact our ability to bacteremic and septic patients, particularly those who are immunocompromised.
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10
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Mourad A, Perfect JR. What Can the Clinical Mycology Laboratory Do for Clinicians Today and Tomorrow? CURRENT CLINICAL MICROBIOLOGY REPORTS 2017. [DOI: 10.1007/s40588-017-0061-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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11
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Frickmann H, Zautner AE, Moter A, Kikhney J, Hagen RM, Stender H, Poppert S. Fluorescence in situ hybridization (FISH) in the microbiological diagnostic routine laboratory: a review. Crit Rev Microbiol 2017; 43:263-293. [PMID: 28129707 DOI: 10.3109/1040841x.2016.1169990] [Citation(s) in RCA: 126] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Early identification of microbial pathogens is essential for rational and conservative antibiotic use especially in the case of known regional resistance patterns. Here, we describe fluorescence in situ hybridization (FISH) as one of the rapid methods for easy identification of microbial pathogens, and its advantages and disadvantages for the diagnosis of pathogens in human infections in the laboratory diagnostic routine. Binding of short fluorescence-labeled DNA or nucleic acid-mimicking PNA probes to ribosomes of infectious agents with consecutive analysis by fluorescence microscopy allows identification of bacterial and eukaryotic pathogens at genus or species level. FISH analysis leads to immediate differentiation of infectious agents without delay due to the need for microbial culture. As a microscopic technique, FISH has the unique potential to provide information about spatial resolution, morphology and identification of key pathogens in mixed species samples. On-going automation and commercialization of the FISH procedure has led to significant shortening of the time-to-result and increased test reliability. FISH is a useful tool for the rapid initial identification of microbial pathogens, even from primary materials. Among the rapidly developing alternative techniques, FISH serves as a bridging technology between microscopy, microbial culture, biochemical identification and molecular diagnostic procedures.
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Affiliation(s)
- Hagen Frickmann
- a German Armed Forces Hospital of Hamburg, Department of Tropical Medicine at the Bernhard Nocht Institute , Hamburg , Germany
| | - Andreas Erich Zautner
- b Department of Medical Microbiology, University Medical Center Göttingen , Göttingen , Germany
| | - Annette Moter
- c University Medical Center Berlin, Biofilmcenter at the German Heart Institute Berlin , Berlin , Germany
| | - Judith Kikhney
- c University Medical Center Berlin, Biofilmcenter at the German Heart Institute Berlin , Berlin , Germany
| | - Ralf Matthias Hagen
- a German Armed Forces Hospital of Hamburg, Department of Tropical Medicine at the Bernhard Nocht Institute , Hamburg , Germany
| | | | - Sven Poppert
- e Institute for Medical Microbiology, Justus-Liebig-University Giessen , Giessen , Germany
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12
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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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13
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Al Hammadi A, Ostrosky-Zeichner L. Epidemiology and Management of Candidiasis in Solid Organ Transplant Recipients. CURRENT FUNGAL INFECTION REPORTS 2016. [DOI: 10.1007/s12281-016-0269-y] [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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14
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Identification of Fungal Pathogens in Tissue Samples from Patients with Proven Invasive Infection by Fluorescence In Situ Hybridization. Methods Mol Biol 2016. [PMID: 27837511 DOI: 10.1007/978-1-4939-6515-1_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Identification of fungal pathogens in clinical samples by hybridization with short oligonucleotide probes is increasingly used in the diagnosis of invasive fungal infections. Rapid and specific fungal identification has been documented in different diagnostic settings allowing for specific patient management. Identification of fungal pathogens in formalin-fixed, paraffin-embedded tissue samples appears to be rewarding as these materials are stored in pathology archives offering an insight into the etiology of deep fungal infections that is often not achieved by non-molecular tests. In contrast to PCR based methods, amplification of target sequences is unnecessary limiting the potential for contamination and localization within infected tissue is possible helping to distinguish between colonization and infection.
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15
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Antifungal Stewardship: an Emerging Practice in Antimicrobial Stewardship. CURRENT CLINICAL MICROBIOLOGY REPORTS 2016. [DOI: 10.1007/s40588-016-0039-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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16
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Radic M, Goic-Barisic I, Novak A, Rubic Z, Tonkic M. Evaluation of PNA FISH® Yeast Traffic Light in identification of Candida species from blood and non-blood culture specimens. Med Mycol 2016; 54:654-8. [PMID: 27067303 DOI: 10.1093/mmy/myw012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 02/24/2016] [Indexed: 01/25/2023] Open
Abstract
PNA FISH(®) (peptide nucleic acid fluorescent in situ hybridization) Yeast Traffic Light (PNA FISH(®) YTL) assay is a commercially avaliable method for rapid identification of Candida spp. directly from positive blood cultures. This report provides a one-year experience in identification of yeasts from 25 specimens (15 positive blood cultures and 10 other clinically significant specimens) using PNA FISH(®) YTL and comparing it to VITEK 2 System. Overall, assay identification compatibility with VITEK 2 System was found among 21/25 (84%) isolates tested. Only 3/25 (12%) of the isolates were not identified, and one isolate was misidentified by the PNA FISH(®) YTL assay. Our results show that the assay is a reliable method in identification of Candida spp. not only from blood cultures, but even from other clinically significant specimens (urine cultures, catheter tip cultures, peritoneal fluid cultures) when compared to automated method like VITEK 2 System. This novel application of the PNA FISH(®) YTL assay could therefore contribute to cost savings and significant benefit to patients, as rapid information about isolated yeast species is provided.
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Affiliation(s)
- Marina Radic
- Department of Clinical Microbiology, University Hospital Centre Split, Split, Croatia University of Split School of Medicine, Split, Croatia
| | - Ivana Goic-Barisic
- Department of Clinical Microbiology, University Hospital Centre Split, Split, Croatia University of Split School of Medicine, Split, Croatia
| | - Anita Novak
- Department of Clinical Microbiology, University Hospital Centre Split, Split, Croatia University of Split School of Medicine, Split, Croatia
| | - Zana Rubic
- Department of Clinical Microbiology, University Hospital Centre Split, Split, Croatia University of Split School of Medicine, Split, Croatia
| | - Marija Tonkic
- Department of Clinical Microbiology, University Hospital Centre Split, Split, Croatia University of Split School of Medicine, Split, Croatia
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17
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Molecular and Mass Spectrometry Detection and Identification of Causative Agents of Bloodstream Infections. Mol Microbiol 2016. [DOI: 10.1128/9781555819071.ch26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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18
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Abstract
Invasive candidiasis is a collective term that refers to a group of infectious syndromes caused by a variety of species of Candida, 5 of which cause most cases. Candidemia is the most commonly recognized syndrome associated with invasive candidiasis. Certain conditions may influence the likelihood for one species versus another in a specific clinical scenario, and this can have important implications for selection of antifungal therapy and the duration of treatment. Molecular diagnostic technology plays an ever-increasing role as an adjunct to traditional culture-based diagnostics, offering significant potential toward improvement in patient care.
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Affiliation(s)
- Todd P McCarty
- University of Alabama at Birmingham, 1900 University Boulevard, 229 THT, Birmingham, AL 35294-0006, USA
| | - Peter G Pappas
- University of Alabama at Birmingham, 1900 University Boulevard, 229 THT, Birmingham, AL 35294-0006, USA.
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Application of Culture-Independent Rapid Diagnostic Tests in the Management of Invasive Candidiasis and Cryptococcosis. J Fungi (Basel) 2015; 1:217-251. [PMID: 29376910 PMCID: PMC5753112 DOI: 10.3390/jof1020217] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Revised: 08/17/2015] [Accepted: 08/17/2015] [Indexed: 12/26/2022] Open
Abstract
The diagnosis of invasive candidiasis (IC) and cryptococcosis is often complicated by slow and insensitive culture-based methods. Such delay results in poor outcomes due to the lack of timely therapeutic interventions. Advances in serological, biochemical, molecular and proteomic approaches have made a favorable impact on this process, improving the timeliness and accuracy of diagnosis with resultant improvements in outcome. This paper will serve as an overview of recent developments in the diagnostic approaches to infections due to these important yeast-fungi.
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20
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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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21
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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: 201] [Impact Index Per Article: 22.3] [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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Machado A, Castro J, Cereija T, Almeida C, Cerca N. Diagnosis of bacterial vaginosis by a new multiplex peptide nucleic acid fluorescence in situ hybridization method. PeerJ 2015; 3:e780. [PMID: 25737820 PMCID: PMC4338769 DOI: 10.7717/peerj.780] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 01/30/2015] [Indexed: 11/20/2022] Open
Abstract
Bacterial vaginosis (BV) is one of most common vaginal infections. However, its diagnosis by classical methods reveals low specificity. Our goal was to evaluate the accuracy diagnosis of 150 vaginal samples with research gold standard methods and our Peptide Nucleic Acid (PNA) probes by Fluorescence in situ Hybridization (FISH) methodology. Also, we described the first PNA-FISH methodology for BV diagnosis, which provides results in approximately 3 h. The results showed a sensitivity of 84.6% (95% confidence interval (CI), from 64.3 to 95.0%) and a specificity of 97.6% (95% CI [92.6-99.4%]), demonstrating the higher specificity of the PNA-FISH method and showing false positive results in BV diagnosis commonly obtained by the classical methods. This methodology combines the specificity of PNA probes for Lactobacillus species and G. vaginalis visualization and the calculation of the microscopic field by Nugent score, allowing a trustful evaluation of the bacteria present in vaginal microflora and avoiding the occurrence of misleading diagnostics. Therefore, the PNA-FISH methodology represents a valuable alternative for BV diagnosis.
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Affiliation(s)
- António Machado
- Centre of Biological Engineering, LIBRO-Laboratory of Research in Biofilms Rosário Oliveira, University of Minho , Campus de Gualtar, Braga , Portugal
| | - Joana Castro
- Centre of Biological Engineering, LIBRO-Laboratory of Research in Biofilms Rosário Oliveira, University of Minho , Campus de Gualtar, Braga , Portugal
| | - Tatiana Cereija
- Centre of Biological Engineering, LIBRO-Laboratory of Research in Biofilms Rosário Oliveira, University of Minho , Campus de Gualtar, Braga , Portugal
| | - Carina Almeida
- Centre of Biological Engineering, LIBRO-Laboratory of Research in Biofilms Rosário Oliveira, University of Minho , Campus de Gualtar, Braga , Portugal
| | - Nuno Cerca
- Centre of Biological Engineering, LIBRO-Laboratory of Research in Biofilms Rosário Oliveira, University of Minho , Campus de Gualtar, Braga , Portugal
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Design and evaluation of peptide nucleic acid probes for specific identification of Candida albicans. J Clin Microbiol 2014; 53:511-21. [PMID: 25428160 DOI: 10.1128/jcm.02417-14] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Candida albicans is an important cause of systemic fungal infections, and rapid diagnostics for identifying and differentiating C. albicans from other Candida species are critical for the timely application of appropriate antimicrobial therapy, improved patient outcomes, and pharmaceutical cost savings. In this work, two 28S rRNA-directed peptide nucleic acid-fluorescence in situ hybridization (PNA-FISH) probes, P-Ca726 (targeting a novel region of the ribosome) and P-CalB2208 (targeting a previously reported region), were evaluated. Hybridization conditions were optimized by using both fluorescence microscopy (FM) and flow cytometry (FCM), and probes were screened for specificity and discriminative ability against a panel of C. albicans and various nontarget Candida spp. The performance of these PNA probes was compared quantitatively against that of DNA probes or DNA probe/helper combinations directed against the same target regions. Ratiometric analyses of FCM results indicated that both the hybridization quality and yield of the PNA probes were higher than those of the DNA probes. In FCM-based comparisons of the PNA probes, P-Ca726 was found to be highly specific, showing 2.5- to 5.5-fold-higher discriminatory power for C. albicans than P-CalB2208. The use of formamide further improved the performance of the new probe. Our results reinforce the significant practical and diagnostic advantages of PNA probes over their DNA counterparts for FISH and indicate that P-Ca726 may be used advantageously for the rapid and specific identification of C. albicans in clinical and related applications, especially when combined with FCM.
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Gavaldà J, Meije Y, Fortún J, Roilides E, Saliba F, Lortholary O, Muñoz P, Grossi P, Cuenca-Estrella M. Invasive fungal infections in solid organ transplant recipients. Clin Microbiol Infect 2014; 20 Suppl 7:27-48. [DOI: 10.1111/1469-0691.12660] [Citation(s) in RCA: 134] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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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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Drew RH, Townsend ML, Pound MW, Johnson SW, Perfect JR. Recent advances in the treatment of life-threatening, invasive fungal infections. Expert Opin Pharmacother 2013; 14:2361-74. [DOI: 10.1517/14656566.2013.838217] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Heil EL, Daniels LM, Long DM, Rodino KG, Weber DJ, Miller MB. Impact of a rapid peptide nucleic acid fluorescence in situ hybridization assay on treatment of Candida infections. Am J Health Syst Pharm 2013; 69:1910-4. [PMID: 23111676 DOI: 10.2146/ajhp110604] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
PURPOSE The impact of a rapid peptide nucleic acid fluorescence in situ hybridization (PNA FISH) assay with an antimicrobial stewardship intervention on the treatment of Candida infections was studied. METHODS The utility of implementing the PNA FISH assay with an antimicrobial stewardship intervention in hospitalized patients with candidemia was evaluated by measuring the median time to Candida species identification, time to targeted therapy, and clinical outcomes, including time to culture clearance, hospital length of stay, and hospital mortality. Secondary objectives included determining the cost-effectiveness of the PNA FISH assay by assessing estimated antifungal drug costs (as average wholesale price) before (June 26, 2009-September 19, 2010) and after (September 20, 2010-June 13, 2011) test implementation and confirming test accuracy. For both groups, laboratory personnel notified the physician of the results of Gram's stain from blood culture. RESULTS Time to targeted therapy significantly decreased after the implementation of the PNA FISH assay (p = 0.0016). The postimplementation group had a higher rate of culture clearance (p = 0.01). Median time to species identification was 0.2 day with the PNA FISH test versus 4 days with routine methods (p < 0.001). Accounting for the cost of the test itself and the cases in which patients were switched to more-expensive therapy on the basis of the test, we estimated that the PNA FISH test resulted in savings of approximately $415 per patient. CONCLUSION Implementing a PNA FISH test to identify Candida species from yeast-positive blood cultures in conjunction with a pharmacy-driven antimicrobial stewardship protocol decreased the time to targeted antifungal therapy and the time to culture clearance.
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Affiliation(s)
- Emily L Heil
- Department of Pharmacy, University of Maryland Medical Center, Baltimore, USA.
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Machado A, Almeida C, Salgueiro D, Henriques A, Vaneechoutte M, Haesebrouck F, Vieira MJ, Rodrigues L, Azevedo NF, Cerca N. Fluorescence in situ Hybridization method using Peptide Nucleic Acid probes for rapid detection of Lactobacillus and Gardnerella spp. BMC Microbiol 2013; 13:82. [PMID: 23586331 PMCID: PMC3637831 DOI: 10.1186/1471-2180-13-82] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 03/27/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Bacterial vaginosis (BV) is a common vaginal infection occurring in women of reproductive age. It is widely accepted that the microbial switch from normal microflora to BV is characterized by a decrease in vaginal colonization by Lactobacillus species together with an increase of Gardnerella vaginalis and other anaerobes. Our goal was to develop and optimize a novel Peptide Nucleic Acid (PNA) Fluorescence in situ Hybridization assay (PNA FISH) for the detection of Lactobacillus spp. and G. vaginalis in mixed samples. RESULTS Therefore, we evaluated and validated two specific PNA probes by using 36 representative Lactobacillus strains, 22 representative G. vaginalis strains and 27 other taxonomically related or pathogenic bacterial strains commonly found in vaginal samples. The probes were also tested at different concentrations of G. vaginalis and Lactobacillus species in vitro, in the presence of a HeLa cell line. Specificity and sensitivity of the PNA probes were found to be 98.0% (95% confidence interval (CI), from 87.8 to 99.9%) and 100% (95% CI, from 88.0 to 100.0%), for Lactobacillus spp.; and 100% (95% CI, from 92.8 to 100%) and 100% (95% CI, from 81.5 to 100.0%) for G. vaginalis. Moreover, the probes were evaluated in mixed samples mimicking women with BV or normal vaginal microflora, demonstrating efficiency and applicability of our PNA FISH. CONCLUSIONS This quick method accurately detects Lactobacillus spp. and G. vaginalis species in mixed samples, thus enabling efficient evaluation of the two bacterial groups, most frequently encountered in the vagina.
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Affiliation(s)
- António Machado
- IBB - Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
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Abstract
BACKGROUND Morbidity and mortality remain high for patients with invasive fungal infections (IFIs) despite an increasing number of antifungals and other treatments. Many studies indicate that delayed or inaccurate diagnosis and treatment are major causes of poor outcomes in patients with IFIs. OBJECTIVE The aim of the current paper is to provide a review of traditional and newer approaches to the diagnosis of IFIs, with a particular focus on invasive candidiasis (IC) and aspergillosis (IA). Recent studies from the author's institution are highlighted, along with an advancement in cryptococcal meningitis diagnosis that should improve the care of AIDS and its opportunistic infection in many developing countries. FINDINGS Currently available tools for the diagnosis of IFIs include traditional methods like histopathology, culture, and radiology, and newer antigen- and PCR-based diagnostic assays. Attempts have also been made to predict IFIs based on colonization or other factors, including genetic polymorphisms impacting IFI susceptibility in high-risk patients. Biopsy with histopathologic analysis is often not possible in patients suspected of pulmonary aspergillosis due to increased bleeding risk, and blood cultures for IC, IA, or other IFIs are hindered by poor sensitivity and slow turnaround time which delays diagnosis. Radiology is often used to predict IFI but suffers from inability to differentiate certain pathogens and does not generally provide certainty of IFI diagnosis. Newer antigen-based diagnostics for early diagnosis include the β-glucan assay for IFIs, galactomannan assay for IA, and a recent variation on the traditional cryptococcal antigen (CRAG) test with a Lateral Flow Assay for invasive cryptococcosis. PCR-based diagnostics represent additional tools with high sensitivity for the rapid diagnosis of IFIs, although better standardization of these methods is still required for their routine clinical use. CONCLUSION Better understanding of the strengths and weaknesses of currently available diagnostic tools, and further devising linked strategies to best implement them either alone or in combination, would greatly improve early and accurate diagnosis of IFIs and improve their successful management.
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Silveira FP, Kusne S. Candida infections in solid organ transplantation. Am J Transplant 2013; 13 Suppl 4:220-7. [PMID: 23465015 DOI: 10.1111/ajt.12114] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- F P Silveira
- Division of Infectious Diseases, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
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Slavin MA, Grist LM. Invasive Fungal Infections: A Continuing Challenge Report from the 17th International Symposium on Infections in the Immunocompromised Host, Genoa, Italy, 24–27 July 2012. CURRENT FUNGAL INFECTION REPORTS 2013. [DOI: 10.1007/s12281-012-0123-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Canadian clinical practice guidelines for invasive candidiasis in adults. CANADIAN JOURNAL OF INFECTIOUS DISEASES & MEDICAL MICROBIOLOGY 2012; 21:e122-50. [PMID: 22132006 DOI: 10.1155/2010/357076] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Candidemia and invasive candidiasis (C/IC) are life-threatening opportunistic infections that add excess morbidity, mortality and cost to the management of patients with a range of potentially curable underlying conditions. The Association of Medical Microbiology and Infectious Disease Canada developed evidence-based guidelines for the approach to the diagnosis and management of these infections in the ever-increasing population of at-risk adult patients in the health care system. Over the past few years, a new and broader understanding of the epidemiology and pathogenesis of C/IC has emerged and has been coupled with the availability of new antifungal agents and defined strategies for targeting groups at risk including, but not limited to, acute leukemia patients, hematopoietic stem cell transplants and solid organ transplants, and critical care unit patients. Accordingly, these guidelines have focused on patients at risk for C/IC, and on approaches of prevention, early therapy for suspected but unproven infection, and targeted therapy for probable and proven infection.
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Evaluation of the Yeast Traffic Light PNA FISH probes for identification of Candida species from positive blood cultures. J Clin Microbiol 2012; 50:1446-8. [PMID: 22238445 DOI: 10.1128/jcm.06148-11] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Yeast Traffic Light PNA FISH kit (YTL) correctly identified Candida spp. in 207/216 (96%) positive blood cultures. Discordant results were seen with known cross-reacting species and cultures containing Candida lambica and Rhodotorula mucilaginosa. The YTL provides rapid, reliable identification of the five common Candida species found in blood cultures.
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Tsui CK, Woodhall J, Chen W, Lévesque CA, Lau A, Schoen CD, Baschien C, Najafzadeh MJ, de Hoog GS. Molecular techniques for pathogen identification and fungus detection in the environment. IMA Fungus 2011; 2:177-89. [PMID: 22679603 PMCID: PMC3359816 DOI: 10.5598/imafungus.2011.02.02.09] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 11/03/2011] [Indexed: 12/25/2022] Open
Abstract
Many species of fungi can cause disease in plants, animals and humans. Accurate and robust detection and quantification of fungi is essential for diagnosis, modeling and surveillance. Also direct detection of fungi enables a deeper understanding of natural microbial communities, particularly as a great many fungi are difficult or impossible to cultivate. In the last decade, effective amplification platforms, probe development and various quantitative PCR technologies have revolutionized research on fungal detection and identification. Examples of the latest technology in fungal detection and differentiation are discussed here.
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Affiliation(s)
- Clement K.M. Tsui
- Department of Forest Sciences, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - James Woodhall
- The Food and Environment Research Agency, Sand Hutton, York YO41 1LZ, UK
| | - Wen Chen
- Central Experimental Farm, Agriculture and Agri-Food Canada, Ottawa, Canada, K1A OC6
| | - C. André Lévesque
- Central Experimental Farm, Agriculture and Agri-Food Canada, Ottawa, Canada, K1A OC6
| | - Anna Lau
- Centre for Infectious Diseases and Microbiology and the University of Sydney, Westmead Hospital, Westmead, NSW 2145, Australia
- *Current mailing address: Department of Laboratory Medicine, 10 Center Drive, National Institutes of Health, Bethesda, MD 20892, USA
| | - Cor D. Schoen
- Plant Research International, Business Unit Bio-Interactions and Plant Health, PO Box 16, 6700 AA, Wageningen, The Netherlands
| | - Christiane Baschien
- Technische Universität Berlin, Environmental Microbiology, Sekr. FR1-2, Franklinstrasse 29, 10587 Berlin, Germany
- **Current mailing address: Federal Environment Agency Germany, Corrensplatz 1, 14195 Berlin, Germany
| | - Mohammad J. Najafzadeh
- CBS-KNAW Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
- Department of Parasitology and Mycology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - G. Sybren de Hoog
- CBS-KNAW Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
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Non–Culture-Based Methods for the Diagnosis of Invasive Candidiasis. CURRENT FUNGAL INFECTION REPORTS 2011. [DOI: 10.1007/s12281-011-0060-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Emmadi R, Boonyaratanakornkit JB, Selvarangan R, Shyamala V, Zimmer BL, Williams L, Bryant B, Schutzbank T, Schoonmaker MM, Amos Wilson JA, Hall L, Pancholi P, Bernard K. Molecular methods and platforms for infectious diseases testing a review of FDA-approved and cleared assays. J Mol Diagn 2011; 13:583-604. [PMID: 21871973 DOI: 10.1016/j.jmoldx.2011.05.011] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Revised: 05/09/2011] [Accepted: 05/27/2011] [Indexed: 01/03/2023] Open
Abstract
The superior sensitivity and specificity associated with the use of molecular assays has greatly improved the field of infectious disease diagnostics by providing clinicians with results that are both accurate and rapidly obtained. Herein, we review molecularly based infectious disease diagnostic tests that are Food and Drug Administration approved or cleared and commercially available in the United States as of December 31, 2010. We describe specific assays and their performance, as stated in the Food and Drug Administration's Summary of Safety and Effectiveness Data or the Office of In Vitro Diagnostic Device Evaluation and Safety's decision summaries, product inserts, or peer-reviewed literature. We summarize indications for testing, limitations, and challenges related to implementation in a clinical laboratory setting for a wide variety of common pathogens. The information presented in this review will be particularly useful for laboratories that plan to implement or expand their molecular offerings in the near term.
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Affiliation(s)
- Rajyasree Emmadi
- Department of Pathology, University of Illinois at Chicago, Chicago, IL, USA.
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Hsu JL, Ruoss SJ, Bower ND, Lin M, Holodniy M, Stevens DA. Diagnosing invasive fungal disease in critically ill patients. Crit Rev Microbiol 2011; 37:277-312. [PMID: 21749278 DOI: 10.3109/1040841x.2011.581223] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Fungal infections are increasing, with a changing landscape of pathogens and emergence of new groups at risk for invasive disease. We review current diagnostic techniques, focusing on studies in critically ill patients. Microbiological cultures, the current "gold standard", demonstrate poor sensitivity, thus diagnosis of invasive disease in the critically ill is difficult. This diagnostic dilemma results in under- or over-treatment of patients, potentially contributing to poor outcomes and antifungal resistance. While other current diagnostic tests perform moderately well, many lack timeliness, efficacy, and are negatively affected by treatments common to critically ill patients. New nucleic acid-based research is promising.
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Affiliation(s)
- Joe L Hsu
- Division of Pulmonary and Critical Care Medicine, Stanford University School of Medicine, Stanford, CA, USA
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[Update: invasive fungal infections: Diagnosis and treatment in surgical intensive care medicine]. Anaesthesist 2011; 59:30-52. [PMID: 20082061 DOI: 10.1007/s00101-009-1655-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Fungal infections are of great relevance in surgical intensive care and Candida species represent the predominant part of fungal pathogens. Invasive aspergillosis is also relevant especially in patients with chronic pulmonary diseases. It is crucial for therapy success to begin adequate antifungal treatment at an early stage of the disease. Risk stratification of individual patient symptoms is essential for therapy timing. In case of suspected or proven candida infection, fluconazole is the agent of choice when the patient is clinically stable and no azoles have been administrated in advance and the local epidemiology makes azol resistance unlikely. For clinically instable patients with organ dysfunction the echinocandins serve as primary therapy because of their broad spectrum and reasonable safety profile. Due to a relevant proportion of azole resistant Candida species, susceptibility testing should be done routinely. Depending on the species detected de-escalating to an azole is feasible if organ dysfunctions have resolved. An invasive aspergillosis is primarily treated with voriconazole.
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Molecular Approaches to the Diagnosis of Sepsis. Mol Microbiol 2011. [DOI: 10.1128/9781555816834.ch49] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Applications of Fluorescence In Situ Hybridization in Diagnostic Microbiology. Mol Microbiol 2011. [DOI: 10.1128/9781555816834.ch1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Abstract
Bloodstream infections account for 30-40% of all cases of severe sepsis and septic shock, and are major causes of morbidity and mortality. Diagnosis of bloodstream infections must be performed promptly so that adequate antimicrobial therapy can be started and patient outcome improved. An ideal diagnostic technology would identify the infecting organism(s) and their determinants of antibiotic resistance, in a timely manner, so that appropriate pathogen-driven therapy could begin promptly. Unfortunately, despite the essential information it provides, blood culture, the gold standard, largely fails in this purpose because time is lost waiting for bacterial or fungal growth. Several efforts have been made to optimise the performance of blood culture, such as the development of technologies to obtain rapid detection of microorganism(s) directly in blood samples or in a positive blood culture. The ideal molecular method would analyse a patient's blood sample and provide all the information needed to immediately direct optimal antimicrobial therapy for bacterial or fungal infections. Furthermore, it would provide data to assess the effectiveness of the therapy by measuring the clearance of microbial nucleic acids from the blood over time. None of the currently available molecular methods is sufficiently rapid, accurate or informative to achieve this. This review examines the principal advantages and limitations of some traditional and molecular methods commercially available to help the microbiologist and the clinician in the management of bloodstream infections.
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Identification of Fusarium species in formalin-fixed and paraffin-embedded sections by in situ hybridization using peptide nucleic acid probes. J Clin Microbiol 2010; 49:808-13. [PMID: 21106796 DOI: 10.1128/jcm.01149-10] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fusarium has recently emerged as an opportunistic pathogen of humans, but the histological differentiation of Fusarium from Aspergillus and Scedosporium is particularly difficult because these fungi may induce similar clinical features and exhibit filamentous development in host tissues. Thus, there is a need to establish rapid and reliable methods that are applicable to pathological diagnoses. The aim of this study was to evaluate and establish in situ hybridization (ISH) using peptide nucleic acid (PNA) probes targeting the 28S rRNA to identify Fusarium species in tissue sections. This technique was validated using both formalin-fixed and paraffin-embedded pulmonary tissues from mice infected with seven different species of fungi and cell blocks from fungal cultures of 30 strains. As a result, strong positive signals were observed within fungal organisms present in tissues of the lung from mice infected with Fusarium solani. Furthermore, this probe reacted strongly with both F. solani and Fusarium oxysporum in sections from cell blocks. Although some cross-reactivity occurred with the Pseudallescheria boydii in sections from cell blocks, the signal intensity was low and most hyphae were not reactive. In conclusion, it was confirmed that ISH with PNA probes is accurate and is a valuable tool for identifying Fusarium spp. among organisms that have identical morphological features in formalin-fixed and paraffin-embedded sections.
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Willinger B. Speziesdiagnostik: Von der Agarplatte zur Molekularbiologie. Mycoses 2010; 53 Suppl 1:19-25. [DOI: 10.1111/j.1439-0507.2009.01836.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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The era of molecular and other non-culture-based methods in diagnosis of sepsis. Clin Microbiol Rev 2010; 23:235-51. [PMID: 20065332 DOI: 10.1128/cmr.00043-09] [Citation(s) in RCA: 254] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Sepsis, a leading cause of morbidity and mortality throughout the world, is a clinical syndrome with signs and symptoms relating to an infectious event and the consequent important inflammatory response. From a clinical point of view, sepsis is a continuous process ranging from systemic inflammatory response syndrome (SIRS) to multiple-organ-dysfunction syndrome (MODS). Blood cultures are the current "gold standard" for diagnosis, and they are based on the detection of viable microorganisms present in blood. However, on some occasions, blood cultures have intrinsic limitations in terms of sensitivity and rapidity, and it is not expected that these drawbacks will be overcome by significant improvements in the near future. For these principal reasons, other approaches are therefore needed in association with blood culture to improve the overall diagnostic yield for septic patients. These considerations have represented the rationale for the development of highly sensitive and fast laboratory methods. This review addresses non-culture-based techniques for the diagnosis of sepsis, including molecular and other non-culture-based methods. In particular, the potential clinical role for the sensitive and rapid detection of bacterial and fungal DNA in the development of new diagnostic algorithms is discussed.
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Wolk DM, Fiorello AB. Code Sepsis: Rapid Methods To Diagnose Sepsis and Detect Hematopathogens. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/j.clinmicnews.2010.03.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Mandviwala T, Shinde R, Kalra A, Sobel JD, Akins RA. High-throughput identification and quantification of Candida species using high resolution derivative melt analysis of panfungal amplicons. J Mol Diagn 2009; 12:91-101. [PMID: 20007848 DOI: 10.2353/jmoldx.2010.090085] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fungal infections pose unique challenges to molecular diagnostics; fungal molecular diagnostics consequently lags behind bacterial and viral counterparts. Nevertheless, fungal infections are often life-threatening, and early detection and identification of species is crucial to successful intervention. A high throughput PCR-based method is needed that is independent of culture, is sensitive to the level of one fungal cell per milliliter of blood or other tissue types, and is capable of detecting species and resistance mutations. We introduce the use of high resolution melt analysis, in combination with more sensitive, inclusive, and appropriately positioned panfungal primers, to address these needs. PCR-based amplification of the variable internal transcribed regions of the rDNA genes generates an amplicon whose sequence melts with a shape that is characteristic and therefore diagnostic of the species. Simple analysis of the differences between test and reference melt curves generates a single number that calls the species. Early indications suggest that high resolution melt analysis can distinguish all eight major species of Candida of clinical significance without interference from excess human DNA. Candida species, including mixed and novel species, can be identified directly in vaginal samples. This tool can potentially detect, count, and identify fungi in hundreds of samples per day without further manipulation, costs, or delays, offering a major step forward in fungal molecular diagnostics.
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Affiliation(s)
- Tasneem Mandviwala
- Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, Michigan, USA
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Affiliation(s)
- P G Pappas
- Division of Infectious Diseases, University of Alabama at Birmingham, Birmingham, AL, USA.
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Lau A, Chen S, Sleiman S, Sorrell T. Current status and future perspectives on molecular and serological methods in diagnostic mycology. Future Microbiol 2009; 4:1185-222. [DOI: 10.2217/fmb.09.70] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Invasive fungal infections are an important cause of infectious morbidity. Nonculture-based methods are increasingly used for rapid, accurate diagnosis to improve patient outcomes. New and existing DNA amplification platforms have high sensitivity and specificity for direct detection and identification of fungi in clinical specimens. Since laboratories are increasingly reliant on DNA sequencing for fungal identification, measures to improve sequence interpretation should support validation of reference isolates and quality control in public gene repositories. Novel technologies (e.g., isothermal and PNA FISH methods), platforms enabling high-throughput analyses (e.g., DNA microarrays and Luminex® xMAP™) and/or commercial PCR assays warrant further evaluation for routine diagnostic use. Notwithstanding the advantages of molecular tests, serological assays remain clinically useful for patient management. The serum Aspergillus galactomannan test has been incorporated into diagnostic algorithms of invasive aspergillosis. Both the galactomannan and the serum β-D-glucan test have value for diagnosing infection and monitoring therapeutic response.
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Affiliation(s)
- Anna Lau
- Centre for Infectious Diseases & Microbiology, University of Sydney, Sydney, Australia
| | - Sharon Chen
- Centre for Infectious Diseases & Microbiology, University of Sydney, Sydney, Australia and Centre for Infectious Diseases & Microbiology Laboratory Services, Institute of Clinical Pathology & Medical Research, Westmead Hospital, Westmead, NSW 2145, Australia
| | - Sue Sleiman
- Centre for Infectious Diseases & Microbiology Laboratory Services, Institute of Clinical Pathology & Medical Research, Westmead Hospital, Westmead, NSW 2145, Australia
| | - Tania Sorrell
- Centre for Infectious Diseases & Microbiology, Westmead Hospital, Darcy and Hawkesbury Roads, Westmead, NSW 2145, Australia
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