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Goshia T, Aralar A, Wiederhold N, Jenks JD, Mehta SR, Karmakar A, E S M, Sharma A, Sun H, Kebadireng R, White PL, Sinha M, Hoenigl M, Fraley SI. Universal digital high-resolution melting for the detection of pulmonary mold infections. J Clin Microbiol 2024; 62:e0147623. [PMID: 38695528 PMCID: PMC11237519 DOI: 10.1128/jcm.01476-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 02/21/2024] [Indexed: 05/14/2024] Open
Abstract
Invasive mold infections (IMIs) are associated with high morbidity, particularly in immunocompromised patients, with mortality rates between 40% and 80%. Early initiation of appropriate antifungal therapy can substantially improve outcomes, yet early diagnosis remains difficult to establish and often requires multidisciplinary teams evaluating clinical and radiological findings plus supportive mycological findings. Universal digital high-resolution melting (U-dHRM) analysis may enable rapid and robust diagnoses of IMI. A universal fungal assay was developed for U-dHRM and used to generate a database of melt curve signatures for 19 clinically relevant fungal pathogens. A machine learning algorithm (ML) was trained to automatically classify these pathogen curves and detect novel melt curves. Performance was assessed on 73 clinical bronchoalveolar lavage samples from patients suspected of IMI. Novel curves were identified by micropipetting U-dHRM reactions and Sanger sequencing amplicons. U-dHRM achieved 97% overall fungal organism identification accuracy and a turnaround time of ~4 hrs. U-dHRM detected pathogenic molds (Aspergillus, Mucorales, Lomentospora, and Fusarium) in 73% of 30 samples classified as IMI, including mixed infections. Specificity was optimized by requiring the number of pathogenic mold curves detected in a sample to be >8 and a sample volume to be 1 mL, which resulted in 100% specificity in 21 at-risk patients without IMI. U-dHRM showed promise as a separate or combination diagnostic approach to standard mycological tests. U-dHRM's speed, ability to simultaneously identify and quantify clinically relevant mold pathogens in polymicrobial samples, and detect emerging opportunistic pathogens may aid treatment decisions, improving patient outcomes. IMPORTANCE Improvements in diagnostics for invasive mold infections are urgently needed. This work presents a new molecular detection approach that addresses technical and workflow challenges to provide fast pathogen detection, identification, and quantification that could inform treatment to improve patient outcomes.
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Affiliation(s)
- Tyler Goshia
- Department of Bioengineering, University of California San Diego, San Diego, California, USA
| | - April Aralar
- Department of Bioengineering, University of California San Diego, San Diego, California, USA
| | - Nathan Wiederhold
- Department of Pathology, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Jeffrey D Jenks
- Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
- Durham County Department of Public Health, Durham, North Carolina, USA
| | - Sanjay R Mehta
- Department of Medicine, University of California San Diego, San Diego, California, USA
- San Diego Veterans Administration Medical Center, San Diego, California, USA
| | | | - Monish E S
- MelioLabs Inc., Santa Clara, California, USA
| | | | - Haoxiang Sun
- Department of Bioengineering, University of California San Diego, San Diego, California, USA
| | - Refilwe Kebadireng
- Department of Bioengineering, University of California San Diego, San Diego, California, USA
| | - P Lewis White
- Public Health Wales Microbiology Cardiff, Cardiff University, UHW, Cardiff, United Kingdom
- Centre for Trials Research, Division of Infection and Immunity, Cardiff University, UHW, Cardiff, United Kingdom
| | - Mridu Sinha
- MelioLabs Inc., Santa Clara, California, USA
| | - Martin Hoenigl
- Department of Internal Medicine, Medical University of Graz, Graz, Austria
- ECMM Excellence Center for Medical Mycology, Medical University of Graz, Graz, Austria
| | - Stephanie I Fraley
- Department of Bioengineering, University of California San Diego, San Diego, California, USA
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Santhanam P, Labbé C, Tremblay V, Bélanger RR. A rapid molecular diagnostic tool to discriminate alleles of avirulence genes and haplotypes of Phytophthora sojae using high-resolution melting analysis. MOLECULAR PLANT PATHOLOGY 2024; 25:e13406. [PMID: 38009407 PMCID: PMC10799203 DOI: 10.1111/mpp.13406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 10/02/2023] [Accepted: 11/03/2023] [Indexed: 11/28/2023]
Abstract
Effectors encoded by avirulence genes (Avr) interact with the Phytophthora sojae resistance gene (Rps) products to generate incompatible interactions. The virulence profile of P. sojae is rapidly evolving as a result of the large-scale deployment of Rps genes in soybean. For a successful exploitation of Rps genes, it is recommended that soybean growers use cultivars containing the Rps genes corresponding to Avr genes present in P. sojae populations present in their fields. Determination of the virulence profile of P. sojae isolates is critical for the selection of soybean cultivars. High-resolution melting curve (HRM) analysis is a powerful tool, first applied in medicine, for detecting mutations with potential applications in different biological fields. Here, we report the development of an HRM protocol, as an original approach to discriminate effectors, to differentiate P. sojae haplotypes for six Avr genes. An HRM assay was performed on 24 P. sojae isolates with different haplotypes collected from soybean fields across Canada. The results clearly confirmed that the HRM assay discriminated different virulence genotypes. Moreover, the HRM assay was able to differentiate multiple haplotypes representing small allelic variations. HRM-based prediction was validated by phenotyping assays. This HRM assay provides a unique, cost-effective and efficient tool to predict virulence pathotypes associated with six different Avr (1b, 1c, 1d, 1k, 3a and 6) genes from P. sojae, which can be applied in the deployment of appropriate Rps genes in soybean fields.
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Affiliation(s)
- Parthasarathy Santhanam
- Département de PhytologieUniversité LavalQuebecQuebecCanada
- Present address:
Agriculture Agri‐Food Canada, MRDCMordenManitobaCanada
| | - Caroline Labbé
- Département de PhytologieUniversité LavalQuebecQuebecCanada
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Jenks JD, White PL, Kidd SE, Goshia T, Fraley SI, Hoenigl M, Thompson GR. An update on current and novel molecular diagnostics for the diagnosis of invasive fungal infections. Expert Rev Mol Diagn 2023; 23:1135-1152. [PMID: 37801397 PMCID: PMC10842420 DOI: 10.1080/14737159.2023.2267977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 10/04/2023] [Indexed: 10/08/2023]
Abstract
BACKGROUND Invasive fungal infections cause millions of infections annually, but diagnosis remains challenging. There is an increased need for low-cost, easy to use, highly sensitive and specific molecular assays that can differentiate between colonized and pathogenic organisms from different clinical specimens. AREAS COVERED We reviewed the literature evaluating the current state of molecular diagnostics for invasive fungal infections, focusing on current and novel molecular tests such as polymerase chain reaction (PCR), digital PCR, high-resolution melt (HRM), and metagenomics/next generation sequencing (mNGS). EXPERT OPINION PCR is highly sensitive and specific, although performance can be impacted by prior/concurrent antifungal use. PCR assays can identify mutations associated with antifungal resistance, non-Aspergillus mold infections, and infections from endemic fungi. HRM is a rapid and highly sensitive diagnostic modality that can identify a wide range of fungal pathogens, including down to the species level, but multiplex assays are limited and HRM is currently unavailable in most healthcare settings, although universal HRM is working to overcome this limitation. mNGS offers a promising approach for rapid and hypothesis-free diagnosis of a wide range of fungal pathogens, although some drawbacks include limited access, variable performance across platforms, the expertise and costs associated with this method, and long turnaround times in real-world settings.
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Affiliation(s)
- Jeffrey D Jenks
- Durham County Department of Public Health, Durham, North Carolina, USA
- Division of Infectious Diseases, Department of Medicine, Duke University, Durham, North Carolina, USA
| | - P Lewis White
- Public Health Wales Microbiology Cardiff, UHW, United Kingdom and Centre for trials research/Division of Infection/Immunity, Cardiff University, Cardiff, UK
| | - Sarah E Kidd
- National Mycology Reference Centre, SA Pathology, Adelaide, Australia
- School of Biological Sciences, Faculty of Sciences, University of Adelaide, Adelaide, Australia
| | - Tyler Goshia
- Department of Bioengineering, University of California, San Diego, CA, USA
| | - Stephanie I Fraley
- Department of Bioengineering, University of California, San Diego, CA, USA
| | - Martin Hoenigl
- Division of Infectious Diseases, Medical University of Graz, Graz, Austria
- BioTechMed, Graz, Austria
| | - George R Thompson
- University of California Davis Center for Valley Fever, Sacramento, CA, USA
- Department of Internal Medicine, Division of Infectious Diseases, University of California Davis Medical Center, Sacramento, CA, USA
- Department of Medical Microbiology and Immunology, University of California Davis, Davis, CA, USA
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Bazalová O, Cihlář JZ, Dlouhá Z, Bár L, Dráb V, Kavková M. Rapid sourdough yeast identification using panfungal PCR combined with high resolution melting analysis. METHODS IN MICROBIOLOGY 2022; 199:106522. [PMID: 35716843 DOI: 10.1016/j.mimet.2022.106522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 06/10/2022] [Accepted: 06/10/2022] [Indexed: 10/18/2022]
Abstract
The microbial composition of the sourdough starter affects the sourdough bread properties. Therefore, it is crucial to find a tool for rapid, time-saving, and economical identification of the sourdough microbiota. We focused on the rapid identification of sourdough yeasts. We designed a panfungal real time-PCR targeting the ITS2 region (ITS-amplicon) and a fragment of D1/D2 region of 26S rRNA gene (U-amplicon) and used high resolution melting analysis (HRM) for subsequent species identification. The sensitivity and specificity of our method were tested on the reference yeast cultures. We obtained divergent melting peaks (Tm). The further analysis of melt curves suggests the possibility to discriminate yeasts on the genus- and some on species-specific level in the mixed sample. The applicability of this method in routine practice was evaluated on nine sourdough samples. Revealed melt curves of U-amplicons were predominantly characteristic of the sourdough. The evaluation of the Tm and the shape of the melt curve was used to assess the sourdough yeasts. Additionally, using the HRM-PCR method the contamination with the ergot fungus DNA was revealed. Our data showed HRM-PCR is a simple, rapid, and inexpensive tool useful in identifying sourdough yeasts.
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Affiliation(s)
- Olga Bazalová
- Dairy Research Institute, Ltd., Department Tábor, Ke Dvoru 12a, 160 00 Praha, Vokovice, Czech Republic.
| | - Jaromír Z Cihlář
- Dairy Research Institute, Ltd., Department Tábor, Ke Dvoru 12a, 160 00 Praha, Vokovice, Czech Republic; Milcom, a.s., Collection of Dairy Microorganisms - Laktoflora, Ke Dvoru 12a, 160 00 Praha, Vokovice, Czech Republic
| | - Zuzana Dlouhá
- Milcom, a.s., Collection of Dairy Microorganisms - Laktoflora, Ke Dvoru 12a, 160 00 Praha, Vokovice, Czech Republic
| | - Ladislav Bár
- Dairy Research Institute, Ltd., Department Tábor, Ke Dvoru 12a, 160 00 Praha, Vokovice, Czech Republic; Milcom, a.s., Collection of Dairy Microorganisms - Laktoflora, Ke Dvoru 12a, 160 00 Praha, Vokovice, Czech Republic
| | - Vladimír Dráb
- Dairy Research Institute, Ltd., Department Tábor, Ke Dvoru 12a, 160 00 Praha, Vokovice, Czech Republic; Milcom, a.s., Collection of Dairy Microorganisms - Laktoflora, Ke Dvoru 12a, 160 00 Praha, Vokovice, Czech Republic
| | - Miloslava Kavková
- Dairy Research Institute, Ltd., Department Tábor, Ke Dvoru 12a, 160 00 Praha, Vokovice, Czech Republic; Milcom, a.s., Collection of Dairy Microorganisms - Laktoflora, Ke Dvoru 12a, 160 00 Praha, Vokovice, Czech Republic
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White PL, Alanio A, Brown L, Cruciani M, Hagen F, Gorton R, Lackner M, Millon L, Morton CO, Rautemaa-Richardson R, Barnes RA, Donnelly JP, Loffler J. An overview of using fungal DNA for the diagnosis of invasive mycoses. Expert Rev Mol Diagn 2022; 22:169-184. [PMID: 35130460 DOI: 10.1080/14737159.2022.2037423] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
INTRODUCTION Fungal PCR has undergone considerable standardization and together with the availability of commercial assays, external quality assessment schemes and extensive performance validation data, is ready for widespread use for the screening and diagnosis of invasive fungal disease (IFD). AREAS COVERED Drawing on the experience and knowledge of the leads of the various working parties of the Fungal PCR initiative, this review will address general considerations concerning the use of molecular tests for the diagnosis of IFD, before focussing specifically on the technical and clinical aspects of molecular testing for the main causes of IFD and recent technological developments. EXPERT OPINION For infections caused by Aspergillus, Candida and Pneumocystis jirovecii, PCR testing is recommended, combination with serological testing will likely enhance the diagnosis of these diseases. For other IFD (e.g. Mucormycosis) molecular diagnostics, represent the only non-classical mycological approach towards diagnoses and continued performance validation and standardization has improved confidence in such testing. The emergence of antifungal resistance can be diagnosed, in part, through molecular testing. Next-generation sequencing has the potential to significantly improve our understanding of fungal phylogeny, epidemiology, pathogenesis, mycobiome/microbiome and interactions with the host, while identifying novel and existing mechanisms of antifungal resistance and novel diagnostic/therapeutic targets.
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Affiliation(s)
- P Lewis White
- Public Health Wales Microbiology Cardiff, UHW, Cardiff, UK CF14 4XW
| | - Alexandre Alanio
- Laboratoire de Parasitologie-Mycologie, Groupe Hospitalier Lariboisière, Saint-Louis, Fernand Widal, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France.,Université de Paris, Paris, France.,Institut Pasteur, CNRS UMR2000, Unité de Mycologie Moléculaire, Centre National de Reference Mycoses invasives et Antifongiques, Paris, France
| | - Lottie Brown
- NHS Mycology Reference Centre Manchester, ECMM Centre of Excellence, Manchester University NHS Foundation Trust, Wythenshawe Hospital; and Division of Infection, Immunity and Respiratory Medicine, Faculty of Biology, Medicine and Health, University of Manchester, UK
| | | | - Ferry Hagen
- Westerdijk Fungal Biodiversity Institute, Utrecht, The Netherlands & Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Rebecca Gorton
- Dept. of Infection Sciences, Health Services Laboratories (HSL) LLP, London, UK
| | - Michaela Lackner
- Institute of Hygiene and Medical Microbiology, Department of Hygiene, Medical Microbiology and Publics Health, Medical University Innsbruck, Innsbruck, Austria
| | - Laurence Millon
- Parasitology-Mycology Department, University Hospital of Besançon, 25000 Besançon, France.,UMR 6249 CNRS Chrono-Environnement, University of Bourgogne Franche-Comté, 25000 Besançon, France
| | - C Oliver Morton
- Western Sydney University, School of Science, Campbelltown, NSW 2560, Australia
| | - Riina Rautemaa-Richardson
- NHS Mycology Reference Centre Manchester, ECMM Centre of Excellence, Manchester University NHS Foundation Trust, Wythenshawe Hospital; and Division of Infection, Immunity and Respiratory Medicine, Faculty of Biology, Medicine and Health, University of Manchester, UK
| | | | | | - Juergen Loffler
- Department of Internal Medicine II, WÜ4i, University Hospital Wuerzburg, Wuerzburg, Germany
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New Tools in Laboratory Diagnosis of Invasive Fungal Infections. Fungal Biol 2022. [DOI: 10.1007/978-3-030-89664-5_15] [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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7
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Ozkok FO, Celik M. Convolutional neural network analysis of recurrence plots for high resolution melting classification. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2021; 207:106139. [PMID: 34029831 DOI: 10.1016/j.cmpb.2021.106139] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 04/22/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND AND OBJECTIVE High resolution melting (HRM) analysis is a rapid and correct method for identification of species, such as, microorganism, bacteria, yeast, virus, etc. HRM data are produced using real-time polymerase chain reaction (PCR) and unique for each species. Analysis of the HRM data is important for several applications, such as, for detection of diseases (e.g., influenza, zika virus, SARS-Cov-2 and Covid-19 diseases) in health, for identification of spoiled foods in food industry, for analysis of crime scene evidence in forensic investigation, etc. However, the characteristics of the HRM data can change due to the experimental conditions or instrumental settings. In addition, it becomes laborious and time-consuming process as the number of samples increases. Because of these reasons, the analysis and classification of the HRM data become challenging for species which have similar characteristics. METHODS To improve the classification accuracy of HRM data, we propose to use image (visual) representation of HRM data, which we call HRM images, that are generated using recurrence plots, and propose convolutional neural network (CNN) based models for classifying HRM images. In this study, two different types of recurrence plots are generated, which are black-white recurrence plots (BW-RP) and gray scale recurrence plots (GS-RP) and four different CNN models are proposed for classifying HRM data. RESULTS The classification performance of the proposed methods are evaluated based on average classification accuracy and F1 score, specificity, recall, and precision values for each yeast species. When BW-RP representation of HRM data is used as input to the CNN models, the best classification accuracy of 95.2% is obtained. The classification accuracies of CNN models for melting curve and GS-RP data representations of HRM data are 90.13% and 86.13%, respectively. The classification accuracy of support vector machines (SVM) model that take melting curve representation of HRM data is 86.53%. Moreover, when BW-RP representation of HRM data is used as input to the CNN models, the F1 score, specificity, recall and precision values are the highest for almost all of species. CONCLUSIONS Experimental results show that using BW-RP representation of HRM data improved the classification accuracy of HRM data and CNN models that take these images as input outperformed CNN models that take melting curve and GS-RP representations of HRM data as inputs and SVM model that take melting curve representation of HRM data as input.
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Affiliation(s)
- Fatma Ozge Ozkok
- Department of Computer Engineering, Erciyes University, Kayseri, 38039 TURKEY.
| | - Mete Celik
- Department of Computer Engineering, Erciyes University, Kayseri, 38039 TURKEY.
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Bahadori T, Didehdar M, Khansarinezhad B, Shokohi T. Identification of opportunistic and nonopportunistic Exophiala species using high resolution melting analysis. Med Mycol 2021; 58:938-945. [PMID: 31977020 DOI: 10.1093/mmy/myz136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 12/02/2019] [Accepted: 12/20/2019] [Indexed: 01/13/2023] Open
Abstract
Exophiala is a genus comprising several species of opportunistic black yeasts. Exophiala species identification by morphological, physiological, and biochemical characteristics is challenging because of the low degree of phenotypic differences between species and its polyphyletic nature. We aimed to develop a high-resolution melting (HRM) assay based on the internal transcribed spacer (ITS) region to differentiate between pairs of clinical and environmental Exophiala species. HRM primers were designed based on the conserved ITS region of five Exophiala species (E. dermatitidis, E. phaeomuriformis, E. heteromorpha, E. xenobiotica, and E. crusticola). Environmental and clinical Exophiala isolates representing these five species (n = 109) were analyzed. The HRM assay was optimized using clinical and environmental reference isolates (n = 22), and then the results were compared with those obtained with nonreference isolates of Exophiala (n = 87) using two designed primer sets. The designed HRM assay was based on the normalized melting peak approach and two primer sets, and successfully distinguished between the five Exophiala species. The HRM1 primer set provided sufficient resolution, with a melting temperature (Tm) difference of approximately 2.5°C among the analyzed species and of approximately 1°C between E. dermatitidis and E. phaeomuriformis. HRM typing results were in agreement with those of ITS-sequence typing (100% sensitivity and specificity). The developed HRM assay can be used to ascertain the identity of Exophiala species, which may differ in clinical significance, with high accuracy. Its application to identify species directly in clinical samples and/or environmental niches may be possible in the future.
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Affiliation(s)
- Tanaz Bahadori
- Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran
| | - Mojtaba Didehdar
- Department of Medical Mycology and Parasitology, Arak University of Medical Sciences, Arak, Iran
| | - Behzad Khansarinezhad
- Department of Microbiology and Immunology, Arak University of Medical Sciences, Arak, Iran
| | - Tahereh Shokohi
- Invasive Fungi Research Center (IFRC), Mazandaran University of Medical Sciences, Sari, Iran.,Department of Medical Mycology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
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Muthu V, Gandra RR, Dhooria S, Sehgal IS, Prasad KT, Kaur H, Gupta N, Bal A, Ram B, Aggarwal AN, Chakrabarti A, Agarwal R. Role of flexible bronchoscopy in the diagnosis of invasive fungal infections. Mycoses 2021; 64:668-677. [PMID: 33719109 DOI: 10.1111/myc.13263] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 02/23/2021] [Accepted: 02/25/2021] [Indexed: 01/30/2023]
Abstract
BACKGROUND There are sparse data on the role of flexible bronchoscopy (FB) in diagnosing invasive mould infections (IMIs). OBJECTIVE To investigate the safety and usefulness of FB in IMI. We evaluate the factors associated with a successful diagnosis of IMI using FB. Further, we compare subjects of invasive pulmonary aspergillosis (IPA) with pulmonary mucormycosis (PM). METHODS We retrospectively reviewed the clinical features, imaging data, bronchoscopy, microbiology and pathology details of subjects who underwent FB for suspected IMI. We categorised FB as diagnostic if it contributed to the diagnosis of IMI. We performed a multivariate analysis to identify the factors associated with a diagnostic bronchoscopy. RESULTS Of the 3521 FB performed over 18 months, 132 (3.7%) were done for suspected IMIs. We included 107 subjects for the final analysis. The risk factors for IMI included renal transplantation (29.0%), diabetes (27.1%), haematological malignancy (10.3%) and others. We found bronchoscopic abnormalities in 33 (30.8%) subjects, and these were more frequent in those with confirmed PM (67%) than IPA (27%). IMI was confirmed in 79 (14 proven, 48 probable and 17 possible) subjects. FB was diagnostic in 71%. We experienced major complications in three cases (2.7%), including one death. On multivariate analysis, the visualisation of endobronchial abnormalities during FB (OR [95%, CI], 8.5 [1.4-50.4]) was the only factor associated with a diagnostic FB after adjusting for age and various risk factors. CONCLUSIONS Flexible bronchoscopy is a useful and safe procedure in diagnosing IMIs. The presence of endobronchial abnormalities predicts a successful diagnostic yield on FB.
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Affiliation(s)
- Valliappan Muthu
- Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Raghava Rao Gandra
- Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Sahajal Dhooria
- Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Inderpaul Singh Sehgal
- Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Kuruswamy Thurai Prasad
- Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Harsimran Kaur
- Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Nalini Gupta
- Department of Cytology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Amanjit Bal
- Department of Histopathology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Babu Ram
- Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Ashutosh N Aggarwal
- Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Arunaloke Chakrabarti
- Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Ritesh Agarwal
- Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
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Oliveira PV, de Almeida FAN, Lugon MD, Britto KB, Oliveira-Costa J, Santos AR, Paneto GG. Using high-resolution melting to identify Calliphoridae (blowflies) species from Brazil. PeerJ 2020; 8:e9680. [PMID: 33335803 PMCID: PMC7713596 DOI: 10.7717/peerj.9680] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 07/17/2020] [Indexed: 01/22/2023] Open
Abstract
Forensic entomology is the study of insects and other arthropods used in the solution of crimes. Most of entomological evidences strongly depend on accurate species identification. Therefore, new methods are being developed due to difficulties in morphological identification, including molecular methods such as High-Resolution Melting. In this study, we reported a new HRM primer set to identify forensically important Calliphoridae (blowflies) from Brazil. For such purpose, Calliphoridae species of forensic importance in Brazil were listed and confirmed by specialists. Mitochondrial COI sequences of those species were downloaded from databases and aligned, and polymorphic variations were selected for distinction between species. Based on it, HRM primers were designed. Forty-three fly samples representing six species were tested in the HRM assay. All samples had the COI gene sequenced to validate the result. Identifying and differentiating the six species proposed using a combination of two amplicons was possible. The protocol was effective even for old insect specimens, collected and preserved dried for more than ten years, unlike the DNA sequencing technique that failed for those samples. The HRM technique proved to be an alternative tool to DNA sequencing, with advantage of amplifying degraded samples and being fast and cheaper than the sequencing technique.
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Affiliation(s)
- Pablo Viana Oliveira
- Programa de Pós-Graduação em Biotecnologia, Universidade Federal do Espírito Santo, Vitória, Espírito Santo, Brazil
| | | | - Magda Delorence Lugon
- Programa de Pós-Graduação em Biotecnologia, Universidade Federal do Espírito Santo, Vitória, Espírito Santo, Brazil
| | - Karolinni Bianchi Britto
- Programa de Pós-Graduação em Biotecnologia, Universidade Federal do Espírito Santo, Vitória, Espírito Santo, Brazil
| | - Janyra Oliveira-Costa
- Polícia Civil do Estado do Rio de Janeiro, Instituto Médico Legal Afrânio Peixoto, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Alexandre Rosa Santos
- Centro de Ciências Agrárias e Engenharias, Universidade Federal do Espírito Santo, Alegre, Espírito Santo, Brazil
| | - Greiciane Gaburro Paneto
- Programa de Pós-Graduação em Biotecnologia, Universidade Federal do Espírito Santo, Vitória, Espírito Santo, Brazil
- Centro de Ciências Exatas, Naturais e da Saúde, Universidade Federal do Espírito Santo, Alegre, Espírito Santo, Brazil
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McCarthy MW. Harnessing the potential of CRISPR-based platforms to advance the field of hospital medicine. Expert Rev Anti Infect Ther 2020; 18:799-805. [PMID: 32366131 PMCID: PMC7212535 DOI: 10.1080/14787210.2020.1761333] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 04/23/2020] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Clustered regularly interspaced short palindromic repeats (CRISPR) are segments of nucleic acid that play a role in prokaryotic defense and form the basis of a genome editing technology that allows permanent alteration of genetic material. This methodology, known as CRISPR-Cas9, is poised to revolutionize molecular biology, but no literature yet exists on how these advances will affect hospitalists. AREAS COVERED These specialists in inpatient medicine care for a wide variety of hospitalized patients, including those with infectious disease, cancer, cardiovascular disease, autoimmune disease, hematologic disease, and a variety of other conditions that may soon be impacted by advances in gene-modifying technology provided by CRISPR-Cas9. A Literature search was performed using PubMed [1 December 2019-17 April 2020]. EXPERT OPINION This paper reviews the remarkable diagnostic and therapeutic potential of the CRISPR-Cas9 platform and concludes with a look at ethical issues and technical hurdles pertaining to the implementation of permanent gene modification in the practice of Hospital Medicine.
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Affiliation(s)
- Matthew W. McCarthy
- Weill Cornell Medical College, Division of General Internal Medicine, New York-Presbyterian Hospital, New York, NY, USA
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Pakbin B, Akhondzadeh Basti A, Khanjari A, Azimi L, Karimi A. Differentiation of stx1A gene for detection of Escherichia coli serotype O157: H7 and Shigella dysenteriae type 1 in food samples using high resolution melting curve analysis. Food Sci Nutr 2020; 8:3665-3672. [PMID: 32724629 PMCID: PMC7382201 DOI: 10.1002/fsn3.1649] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Revised: 04/26/2020] [Accepted: 04/27/2020] [Indexed: 01/25/2023] Open
Abstract
Escherichia coli serotype O157: H7 and Shigella dysenteriae type 1 as the Shiga toxin-producing bacteria cause some acute gastrointestinal and extraintestinal diseases such as hemorrhagic uremic syndrome and bloody diarrhea in human. Stx genes are the key virulence factors in these pathogens. The aim of this study was to develop HRMA assay to differentiate stx1A gene for detection of E. coli serotype O157: H7 and Sh. dysenteriae type 1 and determine the prevalence of these pathogens in food samples using this method. PCR-HRMA assay and gold standard methods have been carried out for identification of pathogens among 135 different food samples. We found HRMA method a sensitive and specific assay (100 and 100%, respectively) for differentiation of stx1A gene, consequently, detection of these pathogens in food samples. Also, the highest prevalence of E. coli serotype O157: H7 and Sh. dysenteriae type 1 harboring stx1A gene was observed in raw milk and vegetable salad samples, respectively. HRMA as a rapid, inexpensive, sensitive and specific method is suggested to be used for differentiation of stx1A gene to detect E. coli serotype O157: H7 and Sh. dysenteriae type 1 as the key pathogens for safety evaluation of food samples.
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Affiliation(s)
- Babak Pakbin
- Department of Food Hygiene and Quality of ControlFaculty of Veterinary MedicineUniversity of TehranTehranIran
| | - Afshin Akhondzadeh Basti
- Department of Food Hygiene and Quality of ControlFaculty of Veterinary MedicineUniversity of TehranTehranIran
| | - Ali Khanjari
- Department of Food Hygiene and Quality of ControlFaculty of Veterinary MedicineUniversity of TehranTehranIran
| | - Leila Azimi
- Pediatric Infections Research CenterResearch Institute of children’s HealthShahid Beheshti University of Medical SciencesTehranIran
| | - Abdollah Karimi
- Pediatric Infections Research CenterResearch Institute of children’s HealthShahid Beheshti University of Medical SciencesTehranIran
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Knowledge at what cost? An audit of the utility of panfungal PCR performed on bronchoalveolar lavage fluid specimens at a tertiary mycology laboratory. Pathology 2020; 52:584-588. [PMID: 32576387 DOI: 10.1016/j.pathol.2020.03.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 03/23/2020] [Accepted: 03/31/2020] [Indexed: 11/21/2022]
Abstract
The diagnostic utility and costs of panfungal PCR assays for invasive fungal disease (IFD) from bronchoalveolar lavage fluid (BALF) specimens are incompletely defined. In a retrospective audit, panfungal PCR results from 2014-2018 were matched with information on request forms and the registrar/microbiologist diary of clinical liaison. Identification of a single fungus other than a commensal was considered potentially clinically significant, and assessed for clinical relevance. Of 1002 specimens tested, an estimated 90% were requested in patients without clinical suspicion of IFD. There were 530 (52.9%) PCR-positive results of which 485/530 (91.5%) identified multiple fungal species or commensal fungi; 45 (8.5%) were clinically significant but only in 12 (1.2%) was panfungal PCR the sole diagnostic test leading to IFD diagnosis, all in immunocompromised patients with clinical suspicion of IFD. Costs of panfungal PCR tests averaged AUD 133 per test, or AUD 26,767/annum. However, the average cost-per-diagnosis achieved was AUD 15,978/annum. Limiting testing to patients at risk and with clinical suspicion of IFD, may save over AUD 13,383/annum (assuming 50-90% reduction in testing). The value-added utility of panfungal PCR on BALF is 1.2% (12/1002). We have since introduced pre-analytical stewardship limiting routine panfungal PCR testing of BALF to high-risk patients in our hospital.
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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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Gabaldón T. Recent trends in molecular diagnostics of yeast infections: from PCR to NGS. FEMS Microbiol Rev 2019; 43:517-547. [PMID: 31158289 PMCID: PMC8038933 DOI: 10.1093/femsre/fuz015] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 05/31/2019] [Indexed: 12/29/2022] Open
Abstract
The incidence of opportunistic yeast infections in humans has been increasing over recent years. These infections are difficult to treat and diagnose, in part due to the large number and broad diversity of species that can underlie the infection. In addition, resistance to one or several antifungal drugs in infecting strains is increasingly being reported, severely limiting therapeutic options and showcasing the need for rapid detection of the infecting agent and its drug susceptibility profile. Current methods for species and resistance identification lack satisfactory sensitivity and specificity, and often require prior culturing of the infecting agent, which delays diagnosis. Recently developed high-throughput technologies such as next generation sequencing or proteomics are opening completely new avenues for more sensitive, accurate and fast diagnosis of yeast pathogens. These approaches are the focus of intensive research, but translation into the clinics requires overcoming important challenges. In this review, we provide an overview of existing and recently emerged approaches that can be used in the identification of yeast pathogens and their drug resistance profiles. Throughout the text we highlight the advantages and disadvantages of each methodology and discuss the most promising developments in their path from bench to bedside.
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Affiliation(s)
- Toni Gabaldón
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr Aiguader 88, Barcelona 08003, Spain
- Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
- ICREA, Pg Lluís Companys 23, 08010 Barcelona, Spain
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Xanthopoulou A, Ganopoulos I, Tryfinopoulou P, Panagou EZ, Osanthanunkul M, Madesis P, Kizis D. Rapid and accurate identification of black aspergilli from grapes using high-resolution melting (HRM) analysis. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2019; 99:309-314. [PMID: 29876941 DOI: 10.1002/jsfa.9189] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 06/04/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND Aspergillus is a diverse genus of fungi with high economic and social impact. Various species that belong to section Nigri (black aspergilli) are common agents of grape spoilage and potent producers of ochratoxin A (OTA), a mycotoxin associated with various nephrotoxic and immunotoxic effects in humans. Black aspergilli are difficult to classify following only phenotypic criteria; thus chemotaxonomic and molecular methods are employed in parallel with phenotypic ones for species characterization. These approaches, though accurate and replicable, require more than one individual step and are to a certain extent laborious when a rapid identification of these species is required. RESULTS The aim of this study was to develop a high-resolution melting polymerase chain reaction (HRM-PCR) assay as a rapid method for identification of Aspergillus spp. section Nigri isolates and their detection in grape samples. Melt curve analysis of amplicons originating from the internal transcribed spacer 2 (ITS2) ribosomal region generated species-specific HRM curve profiles, enabling the accurate differentiation of the analyzed genotypes. Furthermore, the assay was able to identify A. carbonarius, A. tubingensis, A. niger, A. ibericus and A. japonicus in grape samples artificially inoculated with conidia of these fungi. CONCLUSION To our knowledge this is the first report on the development of an HRM-PCR assay for the identification of black Aspergillus species in grape samples. © 2018 Society of Chemical Industry.
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Affiliation(s)
| | - Ioannis Ganopoulos
- Institute of Plant Breeding and Genetic Resources ELGO-DEMETER, Thessaloniki, Greece
| | - Paschalitsa Tryfinopoulou
- Laboratory of Food Microbiology and Biotechnology, Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens, Greece
| | - Efstathios Z Panagou
- Laboratory of Food Microbiology and Biotechnology, Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens, Greece
| | - Maslin Osanthanunkul
- Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand
- Center of Excellence in Bioresources for Agriculture, Industry and Medicine, Chiang Mai University, Chiang Mai, Thailand
| | | | - Dimosthenis Kizis
- Laboratory of Mycology, Department of Phytopathology, Benaki Phytopathological Institute, Athens, Greece
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Detection and identification of fungi in bronchoalveolar lavage fluid from immunocompromised patients using panfungal PCR. Folia Microbiol (Praha) 2018; 64:421-428. [PMID: 30535753 DOI: 10.1007/s12223-018-00669-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 11/29/2018] [Indexed: 01/24/2023]
Abstract
Rapid diagnostics of fungal pneumonia and initiation of appropriate therapy are still challenging. In this study, we used two panfungal assays to test bronchoalveolar lavage fluid (BALF) samples to prove their ability to confirm invasive fungal disease diagnosis and identify causative agents. Two methods targeting different fungal rDNA regions were used, and the obtained PCR products were sequenced directly or after cloning. In total, 106 BALF samples from 104 patients were tested. After sequencing, we obtained 578 sequences. Four hundred thirty-seven sequences were excluded from further analysis due to duplication (n = 335) or similarity with sequences detected in the extraction control sample (n = 102); 141 unique sequences were analyzed. Altogether, 23/141 (16%) of the fungi detected belonged to pathogenic species, and 63/141 (45%) were identified as various yeasts; a variety of environmental or very rare fungal human pathogens represented 29/141 (21%) of the total and 26/141 (18%) were described as uncultured fungus. Panfungal PCR detected fungal species that would be missed by specific methods in only one case (probable cryptococcosis). Panfungal PCR followed by sequencing has limited use for testing BALF samples due to frequent commensal or environmental fungal species pickup.
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Abstract
INTRODUCTION Fungal infection burden related to Mucorales has been on the rise with significant associated morbidity and mortality. The major obstacle in the management has been lack of a non-invasive rapid and a reliable diagnostic test. Developing a culture-independent biomarker for the early diagnosis of mucormycosis is a major unmet need in modern mycology. Several approaches have been developed, such as immunohistochemistry (IHC) that can confirm the histopathologic diagnosis of the invasive mold infection, polymerase chain reaction (PCR) on formalin-fixed paraffin-embedded (FFPE) or fresh tissue, body fluids such as bronchoalveolar fluid (BAL), and detection directly from serum/blood. Serologic tests, matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS), metabolomics and metagenomic shotgun sequencing are other evolving technologies. Area covered: In this review paper, we report the current status of the molecular diagnostics in the diagnosis of mucormycosis: serologic tests, IHC, PCR, protein-based with MALDI-TOF, metabolomics and metagenomic sequencing. Expert commentary: This review will conclude with an expert commentary on the potential uses/challenges of the currently available tests and the future of molecular diagnostics for mucormycosis.
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Affiliation(s)
- Sanjeet S Dadwal
- a Division of Infectious Disease , City of Hope National Medical Center , Duarte , CA , USA
| | - Dimitrios P Kontoyiannis
- b Department of Infectious Diseases, Infection Control and Employee Health , The University of Texas MD Anderson Cancer Center , Houston , TX , USA
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Mercier T, Guldentops E, Van Daele R, Maertens J. Diagnosing Invasive Mold Infections: What Is Next. CURRENT FUNGAL INFECTION REPORTS 2018. [DOI: 10.1007/s12281-018-0322-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Wehrle-Wieland E, Affolter K, Goldenberger D, Tschudin Sutter S, Halter J, Passweg J, Tamm M, Khanna N, Stolz D. Diagnosis of invasive mold diseases in patients with hematological malignancies using Aspergillus, Mucorales, and panfungal PCR in BAL. Transpl Infect Dis 2018; 20:e12953. [PMID: 29896857 DOI: 10.1111/tid.12953] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 05/15/2018] [Accepted: 06/05/2018] [Indexed: 12/13/2022]
Abstract
BACKGROUND Accurate diagnosis of invasive mold diseases (IMD) remains challenging. Here, the performance of panfungal PCR, Aspergillus and MucoralesPCR in bronchoalveolar lavage (BAL) was evaluated. METHODS We conducted a single-center study including 167 hematologic patients at risk for IMD with BAL performed 2011-2014. Diagnostic performance of single tests (Aspergillus-, Mucorales-, and panfungal PCR, galactomannan (GM)≥0.5 and ≥1, culture/cytology) or in combination was calculated for predicting IMD comparing proven/probable or proven/probable/possible IMD vs no IMD, respectively. RESULTS IMD was classified as proven (n = 6), probable (n = 31), possible (n = 29) and no IMD (n = 101) according to EORTC/MSG criteria. GM ≥ 0.5 in BAL showed the highest sensitivity with 81% for diagnosing IMD whereas the other tests only 5%-35%. By contrast, specificity was highest for panfungal PCR with 99% and GM ≥ 1, Mucorales and AspergillusPCR reached specificity ≥91%. When combining the tests, GM ≥ 0.5 and panfungal PCR show a sensitivity and specificity of 87% and 78% for IMD or with AspergillusPCR a sensitivity and specificity of 88% and 72% for invasive pulmonary aspergillosis, respectively. Including possible IMD patients did not improve the sensitivity of PCRs. In probable/proven IMD patients, the addition of panfungal PCR resulted further in detection of Fusarium species and Alternaria species, and the MucoralesPCR was positive in 2 probable IMD cases. CONCLUSION This study illustrates that the diagnosis of IMD is still very problematic and lacks objectivity. Together with GM in BAL, the PCRs may prove an addition to the current available diagnostic armamentarium in IMD because of their ability to identify molds on a species level.
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Affiliation(s)
- Elisabeth Wehrle-Wieland
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital of Basel, Basel, Switzerland
| | - Kristina Affolter
- Clinic of Pulmonary Medicine and Respiratory Cell Research, University Hospital Basel, Basel, Switzerland
| | | | - Sarah Tschudin Sutter
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital of Basel, Basel, Switzerland
| | - Joerg Halter
- Division of Hematology, University Hospital Basel, Basel, Switzerland
| | - Jakob Passweg
- Division of Hematology, University Hospital Basel, Basel, Switzerland
| | - Michael Tamm
- Clinic of Pulmonary Medicine and Respiratory Cell Research, University Hospital Basel, Basel, Switzerland
| | - Nina Khanna
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital of Basel, Basel, Switzerland
| | - Daiana Stolz
- Clinic of Pulmonary Medicine and Respiratory Cell Research, University Hospital Basel, Basel, Switzerland
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Fidler G, Kocsube S, Leiter E, Biro S, Paholcsek M. DNA Barcoding Coupled with High Resolution Melting Analysis Enables Rapid and Accurate Distinction of Aspergillus species. Med Mycol 2018; 55:642-659. [PMID: 27915305 DOI: 10.1093/mmy/myw127] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 10/17/2016] [Indexed: 01/24/2023] Open
Abstract
We describe a high-resolution melting (HRM) analysis method that is rapid, reproducible, and able to identify reference strains and further 40 clinical isolates of Aspergillus fumigatus (14), A. lentulus (3), A. terreus (7), A. flavus (8), A. niger (2), A. welwitschiae (4), and A. tubingensis (2). Asp1 and Asp2 primer sets were designed to amplify partial sequences of the Aspergillus benA (beta-tubulin) genes in a closed-, single-tube system. Human placenta DNA, further Aspergillus (3), Candida (9), Fusarium (6), and Scedosporium (2) nucleic acids from type strains and clinical isolates were also included in this study to evaluate cross reactivity with other relevant pathogens causing invasive fungal infections. The barcoding capacity of this method proved to be 100% providing distinctive binomial scores; 14, 34, 36, 35, 25, 15, 26 when tested among species, while the within-species distinction capacity of the assay proved to be 0% based on the aligned thermodynamic profiles of the Asp1, Asp2 melting clusters allowing accurate species delimitation of all tested clinical isolates. The identification limit of this HRM assay was also estimated on Aspergillus reference gDNA panels where it proved to be 10-102 genomic equivalents (GE) except the A. fumigatus panel where it was 103 only. Furthermore, misidentification was not detected with human genomic DNA or with Candida, Fusarium, and Scedosporium strains. Our DNA barcoding assay introduced here provides results within a few hours, and it may possess further diagnostic utility when analyzing standard cultures supporting adequate therapeutic decisions.
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Affiliation(s)
- Gabor Fidler
- University of Debrecen, Faculty of Medicine, Department of Human Genetics, Debrecen, Hungary
| | - Sandor Kocsube
- University of Szeged, Faculty of Science & Informatics, Department of Microbiology, Szeged, Hungary
| | - Eva Leiter
- University of Debrecen, Faculty of Science and Technology, Department of Biotechnology and Microbiology, Debrecen, Hungary
| | - Sandor Biro
- University of Debrecen, Faculty of Medicine, Department of Human Genetics, Debrecen, Hungary
| | - Melinda Paholcsek
- University of Debrecen, Faculty of Medicine, Department of Human Genetics, Debrecen, Hungary
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McCarthy MW, Petraitiene R, Walsh TJ. Nucleic acid amplification methodologies for the detection of pulmonary mold infections. Expert Rev Mol Diagn 2017; 17:271-279. [PMID: 28218019 DOI: 10.1080/14737159.2017.1293528] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
INTRODUCTION The detection of pulmonary mold infections has historically required technically demanding methods obtained through invasive procedures. Nucleic acid amplification assays have the potential to circumvent the technical hurdles associated with diagnosis, but are not without potential pitfalls. Areas covered: In this paper, the authors review new assays for the diagnosis of pulmonary mold infections due to aspergillosis, mucormycosis, and hyalohyphomycoses as well as uncommon infections caused by dematiaceous molds. Expert commentary: Nucleic acid amplification assays have the potential to rapidly identify patients with invasive mycoses and could shorten the time to implementation of appropriate antimicrobial therapy. However, selection of appropriate patient populations will be crucial to ensure the highest Bayesian positive predictive value for any novel diagnostic platform.
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Affiliation(s)
- Matthew William McCarthy
- a Department of Medicine , Joan and Sanford I Weill Medical College of Cornell University - Hospital Medicine , New York , NY , USA
| | - Ruta Petraitiene
- b Department of Medicine , Cornell University , NY , New York City , USA
| | - Thomas J Walsh
- c Department of Medicine , Weill Cornell Medical Center - Transplantation, Oncology Infectious Diseases Program , New York , NY , USA
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Zhao Z, Bao Y, Chu LT, Ho JKL, Chieng CC, Chen TH. Microfluidic bead trap as a visual bar for quantitative detection of oligonucleotides. LAB ON A CHIP 2017; 17:3240-3245. [PMID: 28869261 DOI: 10.1039/c7lc00836h] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We demonstrate a microfluidic bead trap capable of forming a dipstick-type bar visible to the naked eye for simple and quantitative detection of oligonucleotides. We use magnetic microparticles (MMPs) and polystyrene microparticles (PMPs) that are connected and form MMPs-targets-PMPs when target oligonucleotides are present, leaving free PMPs with a number inversely proportional to the amount of targets. Using a capillary flow-driven microfluidic circuitry consisting of a magnetic separator to remove the MMPs-targets-PMPs, the free PMPs can be trapped at the narrowing nozzle downstream, forming a visual bar quantifiable based on the length of PMP accumulation. Such a power-free and instrument-free platform enables a limit of detection at 13 fmol (0.65 nM in 20 μl, S/N = 3) of oligonucleotides and is compatible with single-nucleotide polymorphisms and operation in a complex bio-fluid. Moreover, using DNAzyme as the target oligonucleotide that catalyzes a specific hydrolytic cleavage in the presence of lead ions, we demonstrate a model application that detects lead ions with a limit of detection of 12.2 nM (2.5 μg l-1), providing quantitative and visual detection of lead contamination at resource-limited sites.
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Affiliation(s)
- Zichen Zhao
- Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong Special Administrative Region.
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McCarthy MW, Denning DW, Walsh TJ. Future Research Priorities in Fungal Resistance. J Infect Dis 2017; 216:S484-S492. [PMID: 28911040 DOI: 10.1093/infdis/jix103] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Improved understanding of basic mycological, pharmacological, and immunological processes has led to important advances in the diagnosis and treatment of invasive fungal infections. However, the rise of fungi that are resistant to existing antifungal agents poses a substantial threat to human health. Addressing this expanding problem is an urgent priority for the international research community. In this article, we highlight important diagnostic and therapeutic advances that address the rise of resistant fungi as well as new public health initiatives that warrant further investigation to help curb the spread of these potentially lethal organisms.
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Affiliation(s)
| | - David W Denning
- University Hospital of South Manchester, University of Manchester, Manchester Academic Health Science Centre, United Kingdom
| | - Thomas J Walsh
- Transplantation-Oncology Infectious Diseases Program, Weill Cornell Medicine, New York, New York
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26
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Tanuskova D, Horakova J, Svec P, Bodova I, Lengerova M, Bezdicek M, Poczova M, Koppl J, Kolenova A. First case of invasive Magnusiomyces capitatus infection in Slovakia. Med Mycol Case Rep 2017; 16:12-15. [PMID: 28409093 PMCID: PMC5379865 DOI: 10.1016/j.mmcr.2017.03.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 03/22/2017] [Accepted: 03/28/2017] [Indexed: 11/29/2022] Open
Abstract
Magnusiomyces capitatus (previously known as Geotrichum capitatum or Blastoschizomyces capitatus or Trichosporon capitatum) is a rare cause of fungal infection in immunocompromised patients. Most of these cases (87%) have been reported from the Mediterranean region, as it is extremely rare to recognize it in other regions. Here we report a first case of disseminated M. capitatus infection in Slovakia. The patient – 19 year old woman with myelodysplastic syndrome was diagnosed with M. capitatus fungemia after allogeneic stem cell transplantation. The infection occurred despite antifungal prophylaxis with micafungin, which was in vitro sensitive to the yeast. The treatment according to minimal inhibitory concentrations (micafungin, voriconazol) and granulocyte transfusions were administered. M. capitatus was cleared out from the bloodstream. However, patient died of multiple organ failure. Autopsy showed multiple lesions in organs, but did not prove presence of yeast by histopathology. M. capitatus was confirmed by polymerase chain reaction from all tested organs: heart, brain, lungs, spleen, liver and kidneys. We present the post mortem pictures showing the yeast lesions in affected organs. 2012 Elsevier Ltd. All rights reserved.
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Affiliation(s)
- Dominika Tanuskova
- Department of Paediatric Haematology and Oncology, Comenius University Children's Hospital, Bratislava, Slovakia
| | - Julia Horakova
- Department of Paediatric Haematology and Oncology, Comenius University Children's Hospital, Bratislava, Slovakia
| | - Peter Svec
- Department of Paediatric Haematology and Oncology, Comenius University Children's Hospital, Bratislava, Slovakia
| | - Ivana Bodova
- Department of Paediatric Haematology and Oncology, Comenius University Children's Hospital, Bratislava, Slovakia
| | - Martina Lengerova
- Department of Internal Medicine - Hematology and Oncology, University Hospital Brno, Brno, Czechia
| | - Matej Bezdicek
- Department of Internal Medicine - Hematology and Oncology, University Hospital Brno, Brno, Czechia
| | - Miroslava Poczova
- Department of Mycology, HPL Ltd. a Member of Medirex Group, Bratislava, Slovakia
| | - Jozef Koppl
- Department of Paediatric Anesthesiology, Comenius University Children's Hospital, Bratislava, Slovakia
| | - Alexandra Kolenova
- Department of Paediatric Haematology and Oncology, Comenius University Children's Hospital, Bratislava, Slovakia
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New Panfungal Real-Time PCR Assay for Diagnosis of Invasive Fungal Infections. J Clin Microbiol 2016; 54:2910-2918. [PMID: 27629898 DOI: 10.1128/jcm.01580-16] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 09/08/2016] [Indexed: 11/20/2022] Open
Abstract
The diagnosis of invasive fungal infections (IFIs) is usually based on the isolation of the fungus in culture and histopathological techniques. However, these methods have many limitations often delaying the definitive diagnosis. In recent years, molecular diagnostics methods have emerged as a suitable alternative for IFI diagnosis. When there is not a clear suspicion of the fungus involved in the IFI, panfungal real-time PCR assays have been used, allowing amplification of any fungal DNA. However, this approach requires subsequent amplicon sequencing to identify the fungal species involved, increasing response time. In this work, a new panfungal real-time PCR assay using the combination of an intercalating dye and sequence-specific probes was developed. After DNA amplification, a melting curve analysis was also performed. The technique was standardized by using 11 different fungal species and validated in 60 clinical samples from patients with proven and probable IFI. A melting curve database was constructed by collecting those melting curves obtained from fungal species included in the standardization assay. Results showed high reproducibility (coefficient of variation [CV] < 5%; r > 0.95) and specificity (100%). The overall sensitivity of the technique was 83.3%, with the group of fungi involved in the infection detected in 77.8% of the positive samples with IFIs covered by molecular beacon probes. Moreover, sequencing was avoided in 67.8% of these "probe-positive" results, enabling report of a positive result in 24 h. This technique is fast, sensitive, and specific and promises to be useful for improving early diagnosis of IFIs.
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