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Dunbar SA. Nucleic acid sample preparation techniques for bead-based suspension arrays. Methods 2023; 219:22-29. [PMID: 37716477 DOI: 10.1016/j.ymeth.2023.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 08/30/2023] [Accepted: 09/13/2023] [Indexed: 09/18/2023] Open
Abstract
Multiplexing in biological assays allows the simultaneous detection of multiple analytes in a single reaction, which reduces time, labor, and cost as compared to single reaction-based detection methods. Microsphere- or bead-based suspension array technologies, such as the Luminex® xMAP® system, offer high-throughput detection of nucleic acids through a variety of different assay chemistries. Common with most nucleic acid chemistries, for bead-based or other microarray technologies, is the need for efficient extraction and purification of the nucleic acids from the specimen of interest. Often, the optimal method will be dictated by the requirements of the up-front enzymatic chemistry, such as PCR, primer extension, branched DNA (bDNA), etc. For bead-based microarray platforms, the user must also be cognizant of proteins and other contaminants present in reactions that require heat denaturation, as that can lead to bead aggregation or agglutination, preventing the reading of assay results. This review describes and highlights some of the nucleic acid extraction and purification methods that have been used successfully for bead-based nucleic acid analysis, for both prokaryotic and eucaryotic nucleic acids, from a variety of sample types.
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Affiliation(s)
- Sherry A Dunbar
- Scientific Affairs, Luminex, A DiaSorin Company, 12212 Technology Blvd., Austin, TX 78727, USA.
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2
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Bub T, Hargest V, Tan S, Smith M, Vazquez-Pagan A, Flerlage T, Brigleb P, Meliopoulos V, Lindenbach B, Ramanathan HN, Cortez V, Crawford JC, Schultz-Cherry S. Astrovirus replication is dependent on induction of double-membrane vesicles through a PI3K-dependent, LC3-independent pathway. J Virol 2023; 97:e0102523. [PMID: 37668367 PMCID: PMC10537808 DOI: 10.1128/jvi.01025-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 07/11/2023] [Indexed: 09/06/2023] Open
Abstract
Human astrovirus is a positive-sense, single-stranded RNA virus. Astrovirus infection causes gastrointestinal symptoms and can lead to encephalitis in immunocompromised patients. Positive-strand RNA viruses typically utilize host intracellular membranes to form replication organelles, which are potential antiviral targets. Many of these replication organelles are double-membrane vesicles (DMVs). Here, we show that astrovirus infection leads to an increase in DMV formation through a replication-dependent mechanism that requires some early components of the autophagy machinery. Results indicate that the upstream class III phosphatidylinositol 3-kinase (PI3K) complex, but not LC3 conjugation machinery, is utilized in DMV formation. Both chemical and genetic inhibition of the PI3K complex lead to significant reduction in DMVs, as well as viral replication. Elucidating the role of autophagy machinery in DMV formation during astrovirus infection reveals a potential target for therapeutic intervention for immunocompromised patients. IMPORTANCE These studies provide critical new evidence that astrovirus replication requires formation of double-membrane vesicles, which utilize class III phosphatidylinositol 3-kinase (PI3K), but not LC3 conjugation autophagy machinery, for biogenesis. These results are consistent with replication mechanisms for other positive-sense RNA viruses suggesting that targeting PI3K could be a promising therapeutic option for not only astrovirus, but other positive-sense RNA virus infections.
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Affiliation(s)
- Theresa Bub
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
- Integrated Program of Biomedical Sciences, Department of Microbiology, Immunology, and Biochemistry, University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Virginia Hargest
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Shaoyuan Tan
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Maria Smith
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
- Graduate School of Biomedical Sciences, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Ana Vazquez-Pagan
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
- Graduate School of Biomedical Sciences, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Tim Flerlage
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Pamela Brigleb
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Victoria Meliopoulos
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Brett Lindenbach
- Department of Microbial Pathogenesis, Yale University, New Haven, Connecticut, USA
- Department of Comparative Medicine, Yale University, New Haven, Connecticut, USA
| | - Harish N. Ramanathan
- Department of Microbial Pathogenesis, Yale University, New Haven, Connecticut, USA
- Department of Comparative Medicine, Yale University, New Haven, Connecticut, USA
| | - Valerie Cortez
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Cruz, California, USA
| | - Jeremy Chase Crawford
- Department of Immunology, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Stacey Schultz-Cherry
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
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3
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Bub T, Hargest V, Tan S, Smith M, Vazquez-Pagan A, Flerlage T, Brigleb PH, Meliopoulos V, Lindenbach B, Cortez V, Crawford JC, Schultz-Cherry S. Astrovirus replication is dependent on induction of double membrane vesicles through a PI3K-dependent, LC3-independent pathway. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.11.536492. [PMID: 37090568 PMCID: PMC10120637 DOI: 10.1101/2023.04.11.536492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Human astrovirus is a positive sense, single stranded RNA virus. Astrovirus infection causes gastrointestinal symptoms and can lead to encephalitis in immunocompromised patients. Positive strand RNA viruses typically utilize host intracellular membranes to form replication organelles, which are potential antiviral targets. Many of these replication organelles are double membrane vesicles (DMVs). Here we show that astrovirus infection leads to an increase in DMV formation, and this process is replication-dependent. Our data suggest that astrovirus infection induces rearrangement of endoplasmic reticulum fragments, which may become the origin for DMV formation. Transcriptional data suggested that formation of DMVs during astrovirus infection requires some early components of the autophagy machinery. Results indicate that the upstream class III phosphatidylinositol 3-kinase (PI3K) complex, but not LC3 conjugation machinery, is utilized in DMV formation. Inhibition of the PI3K complex leads to significant reduction in viral replication and release from cells. Elucidating the role of autophagy machinery in DMV formation during astrovirus infection reveals a potential target for therapeutic intervention for immunocompromised patients. Importance These studies provide critical new evidence that astrovirus replication requires formation of double membrane vesicles, which utilize class III PI3K, but not LC3 conjugation autophagy machinery for biogenesis. These results are consistent with replication mechanisms for other positive sense RNA viruses. This suggests that targeting PI3K could be a promising therapeutic option for not only astrovirus, but other positive sense RNA virus infections.
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Hargest V, Bub T, Neale G, Schultz-Cherry S. Astrovirus-induced epithelial-mesenchymal transition via activated TGF-β increases viral replication. PLoS Pathog 2022; 18:e1009716. [PMID: 35452499 PMCID: PMC9067694 DOI: 10.1371/journal.ppat.1009716] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 05/04/2022] [Accepted: 03/30/2022] [Indexed: 11/18/2022] Open
Abstract
Human astroviruses (HAstV), positive sense single-stranded RNA viruses, are one of the leading causes of diarrhea worldwide. Despite their high prevalence, the cellular mechanisms of astrovirus pathogenesis remain ill-defined. Previous studies showed HAstV increased epithelial barrier permeability by causing a re-localization of the tight junction protein, occludin. In these studies, we demonstrate that HAstV replication induces epithelial-mesenchymal transition (EMT), by upregulating the transcription of EMT-related genes within 8 hours post-infection (hpi), followed by the loss of cell-cell contacts and disruption of polarity by 24 hpi. While multiple classical HAstV serotypes, including clinical isolates, induce EMT, the non-classical genotype HAstV-VA1 and two strains of reovirus are incapable of inducing EMT. Unlike the re-localization of tight junction proteins, HAstV-induced EMT requires productive replication and is dependent transforming growth factor-β (TGF-β) activity. Finally, inhibiting TGF-β signaling and EMT reduces viral replication, highlighting its importance in the viral life cycle. This finding puts classical strains of HAstV-1 in an exclusive group of non-oncogenic viruses triggering EMT.
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Affiliation(s)
- Virginia Hargest
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Theresa Bub
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
- Integrated Program of Biomedical Sciences, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Geoffrey Neale
- Hartwell Center for Bioinformatics and Biotechnology, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Stacey Schultz-Cherry
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
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Baek C, Li YG, Yoo HJ, Cui WY, Kang JT, Son J, Min J. Simple and portable on-site system for nucleic acid-based detection of Clostridium difficile in stool samples using two columns containing microbeads and loop-mediated isothermal amplification. Anal Bioanal Chem 2021; 414:613-621. [PMID: 34341839 DOI: 10.1007/s00216-021-03557-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 06/10/2021] [Accepted: 07/15/2021] [Indexed: 10/20/2022]
Abstract
It is challenging to employ nucleic acid-based diagnostics for the in situ detection of Clostridium difficile from complex fecal samples because essential sample preparation and amplification procedures require various experimental resources. In this study, a simple and effective on-site nucleic acid-based detection system was used to detect C. difficile in stool samples. Two columns containing different microbeads, namely, glass and functionalized graphene oxide-coated microbeads, were designed to remove relatively large impurities by filtration and concentrate bacteria, including C. difficile, from stool samples by adsorption. The bacterial nucleic acids were effectively extracted using a small bead beater. The effectiveness of enzyme inhibitors remaining in the sample was efficiently reduced by the direct buffer developed in this study. This sample preparation kit consisting of two simple columns showed better performance in real-time polymerase chain reaction (PCR) and equivalent performance in loop-mediated isothermal amplification (LAMP) than other sample preparation kits, despite 90% simplification of the process. The amplification-ready samples were introduced into two microtubes containing LAMP pre-mixtures (one each for E. coli as an external positive control and C. difficile) by a simple sample loader, which was operated using a syringe. LAMP, which indicates amplification based on color change, was performed at 65 °C in a small water bath. The limit of detection (L.O.D) and analytical sensitivity/specificity of our simple and effective kit were compared with those of a commercial kit. C. difficile in stool samples could be detected within 1 h with 103 cfu/10 mg using LAMP combined simple on-site detection kit.
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Affiliation(s)
- Changyoon Baek
- School of Integrative Engineering, Chung-Ang University, Seoul, 06974, South Korea
| | - Yun Guang Li
- School of Integrative Engineering, Chung-Ang University, Seoul, 06974, South Korea
| | - Hyun Jin Yoo
- School of Integrative Engineering, Chung-Ang University, Seoul, 06974, South Korea
| | - Wen Ying Cui
- School of Integrative Engineering, Chung-Ang University, Seoul, 06974, South Korea
| | - Jia Tong Kang
- School of Integrative Engineering, Chung-Ang University, Seoul, 06974, South Korea
| | - Juwon Son
- School of Integrative Engineering, Chung-Ang University, Seoul, 06974, South Korea
| | - Junhong Min
- School of Integrative Engineering, Chung-Ang University, Seoul, 06974, South Korea.
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Zhang X, Das S, Dunbar S, Tang YW. Molecular and non-molecular approaches to etiologic diagnosis of gastroenteritis. Adv Clin Chem 2020; 99:49-85. [PMID: 32951639 DOI: 10.1016/bs.acc.2020.02.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Gastroenteritis is a major cause of mortality and morbidity globally and rapid identification of the causative pathogen is important for appropriate treatment and patient management, implementation of effective infection control measures, reducing hospital length of stay, and reducing overall medical costs. Although stool culture and microscopic examination of diarrheal stool has been the primary method for laboratory diagnosis, culture-independent proteomic and genomic tests are receiving increased attention. Antigen tests for stool pathogens are routinely implemented as rapid and simple analytics whereas molecular tests are now available in various formats from high complexity to waived point-of-care tests. In addition, metagenomic next-generation sequencing stands poised for use as a method for both diagnosis and routine characterization of the gut microbiome in the very near future. Analysis of host biomarkers as indicators of infection status and pathogenesis may also become important for prediction, diagnosis, and monitoring of gastrointestinal infection. Here we review current methods and emerging technologies for the etiologic diagnosis of gastroenteritis in the clinical laboratory. Benefits and limitations of these evolving methods are highlighted.
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Affiliation(s)
- Xin Zhang
- Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China; Memorial Sloan Kettering Cancer Center, New York, NY, United States
| | | | | | - Yi-Wei Tang
- Memorial Sloan Kettering Cancer Center, New York, NY, United States; Weill Medical College of Cornell University, New York, NY, United States; Cepheid, Danaher Diagnostic Platform, Shanghai, China.
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Stone JM, Savage A, Hudspeth M, Twombley K, Kasi N, Quiros JA, Arbizu RA, Curry S. Multi-organism gastrointestinal polymerase chain reaction positivity among pediatric transplant vs non-transplant populations: A single-center experience. Pediatr Transplant 2020; 24:e13771. [PMID: 32639105 PMCID: PMC8103891 DOI: 10.1111/petr.13771] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 05/01/2020] [Accepted: 05/26/2020] [Indexed: 12/19/2022]
Abstract
BACKGROUND Diarrhea is a common problem in the pediatric post-solid organ transplant and post-hematopoietic stem cell transplant populations. Infectious etiology incidences are poorly defined, and the possibility of multi-organism positivity is often uninvestigated. The aim of this study is to utilize stool multiplex GIP assays to compare the PTP and NTP regarding the incidence and profiles of single-organism and multi-organism infectious diarrhea. METHODS A single-center retrospective review was conducted, investigating stool multiplex GIP panel results over a more than 3-year period, for pediatric patients. Assays test for 23 viral, bacterial, and protozoal organisms. RESULTS Positive assays in the PTP and NTP were 70/101 (69.3%) and 962/1716 (56.1%), respectively (P = .009). Thirty-two percent (32/101) of assays within the PTP were multi-organism positive, significantly more than 14.8% (254/1716) in the NTP (P < .00001). There was no significant difference in the incidence of single-organism positives, 37.6% (38/101) in PTP and 41.3% (708/1716) in the NTP. The PTP demonstrated a statistically significantly higher incidence of the following organisms within multi-agent positive GIPs (P < .05 for each): Clostridioides difficile, Cryptosporidium, EPEC, norovirus, and sapovirus. CONCLUSIONS The pediatric PTP demonstrates higher incidence of positive GIPs, higher rate of multi-organism positivity, and unique infectious organism incidence profiles. These data can provide a framework for understanding organism-specific pathogenicity factors, assessing the clinical impact of enteric co-infection, and understanding the utility of this testing modality in this unique population.
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Affiliation(s)
- John M. Stone
- Department of Pediatric Gastroenterology Hepatology and Nutrition, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Andrew Savage
- Department of Pediatric Cardiology, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Michelle Hudspeth
- Department of Pediatric Hematology and Oncology, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Katherine Twombley
- Department of Pediatric Nephrology, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Nagraj Kasi
- Department of Pediatric Gastroenterology Hepatology and Nutrition, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Jose Antonio Quiros
- Department of Pediatric Gastroenterology Hepatology and Nutrition, Mount Sinai Kravis Children’s Hospital, New York, New York, USA
| | - Ricardo A. Arbizu
- Department of Pediatric Gastroenterology Hepatology and Nutrition, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Scott Curry
- Department of Infectious Disease, Medical University of South Carolina, Charleston, South Carolina, USA
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Tarr GAM, Lin CY, Vandermeer B, Lorenzetti DL, Tarr PI, Chui L, Hartling L, Freedman SB. Diagnostic Test Accuracy of Commercial Tests for Detection of Shiga Toxin-Producing Escherichia coli: A Systematic Review and Meta-Analysis. Clin Chem 2020; 66:302-315. [PMID: 32040589 DOI: 10.1093/clinchem/hvz006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 08/07/2019] [Indexed: 12/25/2022]
Abstract
BACKGROUND Rapid detection of Shiga toxin-producing Escherichia coli (STEC) enables appropriate monitoring and treatment. We synthesized available evidence to compare the performance of enzyme immunoassay (EIA) and PCR tests for the detection of STEC. METHODS We searched published and gray literature for studies of STEC EIA and/or PCR diagnostic test accuracy relative to reference standards including at least one nucleic acid amplification test. Two reviewers independently screened studies, extracted data, and assessed quality with the second version of the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Bivariate random effects models were used to meta-analyze the clinical sensitivity and specificity of commercial EIA and PCR STEC diagnostic tests, and summary receiver operator characteristic curves were constructed. We evaluated the certainty of evidence with the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. RESULTS We identified 43 articles reflecting 25 260 specimens. Meta-analysis of EIA and PCR accuracy included 25 and 22 articles, respectively. STEC EIA pooled sensitivity and specificity were 0.681 (95% CI, 0.571-0.773; very low certainty of evidence) and 1.00 (95% CI, 0.998-1.00; moderate certainty of evidence), respectively. STEC PCR pooled sensitivity and specificity were 1.00 (95% CI, 0.904-1.00; low certainty of evidence) and 0.999 (95% CI, 0.997-0.999; low certainty of evidence), respectively. Certainty of evidence was downgraded because of high risk of bias. CONCLUSIONS PCR tests to identify the presence of STEC are more sensitive than EIA tests, with no meaningful loss of specificity. However, given the low certainty of evidence, our results may overestimate the difference in performance.
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Affiliation(s)
- Gillian A M Tarr
- Department of Pediatrics, University of Calgary, Calgary, AB, Canada
| | - Chu Yang Lin
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Ben Vandermeer
- Department of Pediatrics, University of Alberta, Edmonton, AB, Canada
| | | | - Phillip I Tarr
- Department of Pediatrics, Washington University in St. Louis School of Medicine, St. Louis, MO
| | - Linda Chui
- Department of Laboratory Medicine and Pathology, University of Alberta and Alberta Precision Laboratories-ProvLab, Edmonton, AB, Canada
| | - Lisa Hartling
- Department of Pediatrics, University of Alberta, Edmonton, AB, Canada
| | - Stephen B Freedman
- Sections of Pediatric Emergency Medicine and Gastroenterology, Department of Pediatrics, Alberta Children's Hospital and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
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Cortez V, Sharp B, Yao J, Livingston B, Vogel P, Schultz-Cherry S. Characterizing a Murine Model for Astrovirus Using Viral Isolates from Persistently Infected Immunocompromised Mice. J Virol 2019; 93:e00223-19. [PMID: 30971471 PMCID: PMC6580942 DOI: 10.1128/jvi.00223-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 03/26/2019] [Indexed: 12/11/2022] Open
Abstract
Human astroviruses are single-stranded RNA enteric viruses that cause a spectrum of disease ranging from asymptomatic infection to systemic extragastrointestinal spread; however, they are among the least-characterized enteric viruses, and there is a lack of a well-characterized small animal model. Finding that immunocompromised mice were resistant to human astrovirus infection via multiple routes of inoculation, our studies aimed to determine whether murine astrovirus (MuAstV) could be used to model human astrovirus disease. We experimentally infected wild-type mice with MuAstV isolated from immunocompromised mice and found that the virus was detected throughout the gastrointestinal tract, including the stomach, but was not associated with diarrhea. The virus was also detected in the lung. Although virus levels were higher in recently weaned mice, the levels were similar in male and female adult mice. Using two distinct viruses isolated from different immunocompromised mouse strains, we observed virus strain-specific differences in the duration of infection (3 versus 10 weeks) in wild-type mice, indicating that the within-host immune pressure from donor mice shaped the virus kinetics in immunocompetent recipient hosts. Both virus strains elicited minimal pathology and a lack of sustained immunity. In summary, MuAstV represents a useful model for studying asymptomatic human infection and gaining insight into the astrovirus pathogenesis and immunity.IMPORTANCE Astroviruses are widespread in both birds and mammals; however, little is known about the pathogenesis and the immune response to the virus due to the lack of a well-characterized small-animal model. Here we describe two distinct strains of murine astrovirus that cause infections in immunocompetent mice that mirror aspects of asymptomatic human infections, including minimal pathology and short-lived immunity. However, we noted that the duration of infection differed greatly between the strains, highlighting an important facet of these viruses that was not previously appreciated. The ubiquitous nature and diversity of murine astroviruses coupled with the continuous likelihood of reinfection raise the possibility of viral interference with other mouse models of disease.
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Affiliation(s)
- Valerie Cortez
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Bridgett Sharp
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Jiangwei Yao
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Brandi Livingston
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Peter Vogel
- Veterinary Pathology Core, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Stacey Schultz-Cherry
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
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Freeman K, Mistry H, Tsertsvadze A, Royle P, McCarthy N, Taylor-Phillips S, Manuel R, Mason J. Multiplex tests to identify gastrointestinal bacteria, viruses and parasites in people with suspected infectious gastroenteritis: a systematic review and economic analysis. Health Technol Assess 2018; 21:1-188. [PMID: 28619124 DOI: 10.3310/hta21230] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Gastroenteritis is a common, transient disorder usually caused by infection and characterised by the acute onset of diarrhoea. Multiplex gastrointestinal pathogen panel (GPP) tests simultaneously identify common bacterial, viral and parasitic pathogens using molecular testing. By providing test results more rapidly than conventional testing methods, GPP tests might positively influence the treatment and management of patients presenting in hospital or in the community. OBJECTIVE To systematically review the evidence for GPP tests [xTAG® (Luminex, Toronto, ON, Canada), FilmArray (BioFire Diagnostics, Salt Lake City, UT, USA) and Faecal Pathogens B (AusDiagnostics, Beaconsfield, NSW, Australia)] and to develop a de novo economic model to compare the cost-effectiveness of GPP tests with conventional testing in England and Wales. DATA SOURCES Multiple electronic databases including MEDLINE, EMBASE, Web of Science and the Cochrane Database were searched from inception to January 2016 (with supplementary searches of other online resources). REVIEW METHODS Eligible studies included patients with acute diarrhoea; comparing GPP tests with standard microbiology techniques; and patient, management, test accuracy or cost-effectiveness outcomes. Quality assessment of eligible studies used tailored Quality Assessment of Diagnostic Accuracy Studies-2, Consolidated Health Economic Evaluation Reporting Standards and Philips checklists. The meta-analysis included positive and negative agreement estimated for each pathogen. A de novo decision tree model compared patients managed with GPP testing or comparable coverage with patients managed using conventional tests, within the Public Health England pathway. Economic models included hospital and community management of patients with suspected gastroenteritis. The model estimated costs (in 2014/15 prices) and quality-adjusted life-year losses from a NHS and Personal Social Services perspective. RESULTS Twenty-three studies informed the review of clinical evidence (17 xTAG, four FilmArray, two xTAG and FilmArray, 0 Faecal Pathogens B). No study provided an adequate reference standard with which to compare the test accuracy of GPP with conventional tests. A meta-analysis (of 10 studies) found considerable heterogeneity; however, GPP testing produces a greater number of pathogen-positive findings than conventional testing. It is unclear whether or not these additional 'positives' are clinically important. The review identified no robust evidence to inform consequent clinical management of patients. There is considerable uncertainty about the cost-effectiveness of GPP panels used to test for suspected infectious gastroenteritis in hospital and community settings. Uncertainties in the model include length of stay, assumptions about false-positive findings and the costs of tests. Although there is potential for cost-effectiveness in both settings, key modelling assumptions need to be verified and model findings remain tentative. LIMITATIONS No test-treat trials were retrieved. The economic model reflects one pattern of care, which will vary across the NHS. CONCLUSIONS The systematic review and cost-effectiveness model identify uncertainties about the adoption of GPP tests within the NHS. GPP testing will generally correctly identify pathogens identified by conventional testing; however, these tests also generate considerable additional positive results of uncertain clinical importance. FUTURE WORK An independent reference standard may not exist to evaluate alternative approaches to testing. A test-treat trial might ascertain whether or not additional GPP 'positives' are clinically important or result in overdiagnoses, whether or not earlier diagnosis leads to earlier discharge in patients and what the health consequences of earlier intervention are. Future work might also consider the public health impact of different testing treatments, as test results form the basis for public health surveillance. STUDY REGISTRATION This study is registered as PROSPERO CRD2016033320. FUNDING The National Institute for Health Research Health Technology Assessment programme.
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Affiliation(s)
- Karoline Freeman
- Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry, UK
| | - Hema Mistry
- Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry, UK
| | - Alexander Tsertsvadze
- Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry, UK
| | - Pam Royle
- Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry, UK
| | - Noel McCarthy
- Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry, UK
| | - Sian Taylor-Phillips
- Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry, UK
| | | | - James Mason
- Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry, UK
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Cortez V, Freiden P, Gu Z, Adderson E, Hayden R, Schultz-Cherry S. Persistent Infections with Diverse Co-Circulating Astroviruses in Pediatric Oncology Patients, Memphis, Tennessee, USA. Emerg Infect Dis 2018; 23:288-290. [PMID: 28098537 PMCID: PMC5324824 DOI: 10.3201/eid2302.161436] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Human astroviruses are a major cause of pediatric gastroenteritis, especially in immunocompromised children. We conducted a retrospective study to demonstrate that diverse astrovirus genotypes can co-circulate in pediatric oncology patients. A subset of cases is associated with long-term virus shedding (range 17–183 days).
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Alejo-Cancho I, Fernández Avilés F, Capón A, Rodríguez C, Barrachina J, Salvador P, Valls ME, Álvarez-Martínez MJ, Zboromyrska Y, Vila J, Marcos MÁ. Evaluation of a multiplex panel for the diagnosis of acute infectious diarrhea in immunocompromised hematologic patients. PLoS One 2017; 12:e0187458. [PMID: 29099868 PMCID: PMC5669492 DOI: 10.1371/journal.pone.0187458] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 10/22/2017] [Indexed: 02/06/2023] Open
Abstract
Introduction Diarrhea is a frequent complication in hematologic patients, being an infectious cause frequently suspected. Rapid and accurate detection of gastrointestinal pathogens is vital in immunocompromised hosts. The aim of this study was to compare routine diagnostic methods versus a multiplex polymerase chain reaction (PCR) assay for the diagnosis of infectious diarrhea in immunocompromised hematologic patients. Material and methods We conducted a prospective observational study from March 2015 to January 2016 to compare conventional methods for the diagnosis of infectious diarrhea with FIlmArray GI Panel (BioFire-bioMérieux, France). Samples from adult immunocompromised hematologic patients with acute diarrhea were collected. In cases with discordant results, a second multiplex assay was performed (Allplex, Seegene, Korea). The result was considered positive or negative when the same result was obtained by at least two of the methods. Results A total of 95 samples were obtained from 95 patients (median age of 52 years (46–64)). Sixty-one (64%) episodes were hospital-acquired and 34 (36%) were community-acquired diarrhea. Twenty-five (26%) patients had a positive microbiological result, being Clostridium difficile the most frequent pathogen, followed by Campylobacter spp and norovirus. The concordance between FilmArray methods was good (k = 0.79). The FilmArray GI panel showed a sensitivity of 95%, a specificity of 100% for positive results. The time required to obtain results was markedly reduced with the use of multiplex PCR methods. Conclusions Multiplex molecular panels provide a rapid and sensitive tool for the diagnosis of infectious diarrhea, thereby allowing more timely clinical decisions in immunocompromised hematologic patients.
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Affiliation(s)
| | | | - Alicia Capón
- Microbiology Department, Hospital Clinic, Barcelona, Spain
| | | | | | - Pilar Salvador
- Microbiology Department, Hospital Clinic, Barcelona, Spain
| | | | | | | | - Jordi Vila
- Microbiology Department, Hospital Clinic, Barcelona, Spain
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Mhaissen MN, Rodriguez A, Gu Z, Zhu H, Tang L, Sun Y, Schultz-Cherry ST, Hayden RT, Adderson EE. Epidemiology of Diarrheal Illness in Pediatric Oncology Patients. J Pediatric Infect Dis Soc 2017; 6:275-280. [PMID: 27578209 DOI: 10.1093/jpids/piw050] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 07/25/2016] [Indexed: 11/12/2022]
Abstract
BACKGROUND Diarrhea is common in children with cancer, but this has not been systematically studied to date. METHODS Remnant stool samples collected between January 2010 and June 2011 from pediatric oncology patients with diarrhea were tested for bacterial, viral, and parasitic enteropathogens using a combination of standard-of-care (SOC) diagnostic tests, including broad-range, real-time polymerase chain reaction (PCR) assays for adenoviruses, astroviruses, and sapoviruses and 2 commercially available multiplexed PCR assays. Corresponding demographic and clinical data were abstracted from patients' medical records. RESULTS One hundred fourteen episodes of diarrhea in 93 patients (median age, 3.7 years; range, 0.2-18.8) were included in the study. No patients died, but morbidity was significant. A total of 158 potential pathogens were detected in 114 diarrhea episodes, with >1 organism in one third of these; the most common were Clostridium difficile, noroviruses, adenoviruses, and astroviruses. Clostridium difficile, in combination with norovirus or adenovirus, was most common when >1 pathogen was detected. When both studies were obtained, SOC and broadly multiplexed PCR tests were concordant in 64 episodes (56%). Forty-five pathogens (28%) were identified retrospectively by broadly multiplexed PCR assays only. A total of 19 (13%) were detected by SOC real-time PCR assays but not by either commercially available multiplexed PCR assay. CONCLUSIONS Most pediatric oncology patients in this study had 1 or more potential infectious causes for their diarrhea. Additional studies are warranted to understand the natural history of gastroenteritis in this patient population. Although broadly multiplexed PCR assays offer some advantages over conventional testing, there may be disadvantages to their use for the diagnosis of infectious gastroenteritis that are unique to pediatric oncology patients.
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Affiliation(s)
| | | | | | | | - Li Tang
- Biostatistics, St. Jude Children's Research Hospital
| | - Yilun Sun
- Biostatistics, St. Jude Children's Research Hospital
| | | | | | - Elisabeth E Adderson
- Department of Infectious Diseases.,Department of Pediatrics, University of Tennessee Health Sciences Center, Memphis
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Chao AW, Bhatti M, DuPont HL, Nataro JP, Carlin LG, Okhuysen PC. Clinical features and molecular epidemiology of diarrheagenic Escherichia coli pathotypes identified by fecal gastrointestinal multiplex nucleic acid amplification in patients with cancer and diarrhea. Diagn Microbiol Infect Dis 2017; 89:235-240. [PMID: 28931467 DOI: 10.1016/j.diagmicrobio.2017.08.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 08/06/2017] [Indexed: 01/29/2023]
Abstract
Diarrheagenic Escherichia coli (DEC) pathotypes with differing epidemiology and clinical features, are known causes of disease with worldwide occurrence. At a major cancer center in the U.S., we studied patients with cancer and diarrhea for whom a GI Biofire FilmArray multiplex GI panel (BFM) was performed. An enteropathogen was identified in 382 of 2017 (19%) samples distributed across 311 patients. Of these, 60/311(19%) were positive for DEC. Patients receiving hematopoietic stem cell transplants (HSCT) 29/60 (48%) or with a hematologic malignancy 17/60 (28%) accounted for the majority of DEC cases. Enteropathogenic E. coli (EPEC, n=35 [58%]), enteroaggregative E. coli (EAEC, n=10 [17%]) and Shiga toxin producing E. coli (STEC, n=3 [5%]) were the most common DEC identified and peaked in the summer months. Stool cultures confirmed infections in 6/10 (60%) EAEC (five typical AggR+), and EPEC was recovered in 8/35 (22%) samples (all atypical eaeA+, bfp-). DEC was identified in 22 cases (37%) that developed diarrhea >48hours after admission suggesting health care acquisition. Chronic infections were found in 2 EPEC and 1 EAEC cases that were tested at 1month or beyond with shedding that ranged from 58 to >125days. Two patients that underwent hematopoietic stem cell transplantation carried EAEC strains resistant to multiple antibiotics including fluoroquinolones and expressed extended spectrum beta lactamases. While in some instances BFM results were not verified in culture and could represent false positives, DEC pathotypes, especially EPEC and EAEC, caused chronic infections with antimicrobial-resistant strains in a subset of immunosuppressed cancer patients.
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Affiliation(s)
- Andrew W Chao
- Department of Infectious Diseases, Infection Control and Employee Health, The University of Texas M.D. Anderson Cancer Center, Houston, TX; Section of Infectious Diseases, Baylor College of Medicine, Houston, TX
| | - Micah Bhatti
- Department of Laboratory Medicine, The University of Texas M.D. Anderson Cancer Center, Houston, TX
| | - Herbert L DuPont
- Section of Infectious Diseases, Baylor College of Medicine, Houston, TX; Department of Epidemiology, Human Genetics and Environmental Health, The University of Texas School of Public Health, Houston, TX
| | - James P Nataro
- Department of Pediatrics, The University of Virginia School of medicine, Charlottesville, VA
| | - Lily G Carlin
- Department of Infectious Diseases, Infection Control and Employee Health, The University of Texas M.D. Anderson Cancer Center, Houston, TX
| | - Pablo C Okhuysen
- Department of Infectious Diseases, Infection Control and Employee Health, The University of Texas M.D. Anderson Cancer Center, Houston, TX; Section of Infectious Diseases, Baylor College of Medicine, Houston, TX; Department of Epidemiology, Human Genetics and Environmental Health, The University of Texas School of Public Health, Houston, TX.
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Characterization of astrovirus-associated gastroenteritis in hospitalized children under five years of age. INFECTION GENETICS AND EVOLUTION 2017; 53:94-99. [PMID: 28536072 DOI: 10.1016/j.meegid.2017.05.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 04/28/2017] [Accepted: 05/19/2017] [Indexed: 11/23/2022]
Abstract
PURPOSE The aim of this study was to determine the incidence and genetic diversity of astrovirus (AstV) detected in children hospitalized for gastroenteritis (GE). METHODS A multi-center, hospital-based surveillance study was conducted across Lebanon to investigate the incidence of AstV among diarrheal hospitalizations. Viral RNA was extracted from stool samples collected between 2011 and 2013 from children, below the age of 5years, hospitalized for GE at six medical centers across Lebanon. Demographic and clinical data were collected and analyzed. RNA of eligible samples (n=739) was screened by two AstV-specific PCR assays followed by genotype-specific PCR. Sanger sequencing and phylogenetic analysis were performed for genotypic characterization. RESULTS Overall, 5.5% (41/739) of rotavirus-negative stool samples collected from hospitalized children <5years old tested positive for AstV infection. AstV infections were detected all year long. Diarrhea, dehydration, vomiting and fever were the most common symptoms associated with AstV infections. Children aged 48-59months had the highest incidence of AstV. Using the Vesikari Scoring System to assess clinical severity, 85.4% of children with AstV had a score>11, indicating severe GE. Genotype-specific PCR identified 22 classical and 4 MLB-like AstV specimens. Further sequencing and phylogenetic analysis of orf1b and orf2 genes revealed that AstV classical 1-3, 5, 6, and 8, MLB-1, VA-1 and -2 genotypes circulated in Lebanon. Recombination between classical AstV strains was detected in several cases as evident by the lack of congruency in the tree topologies of the orf1b and orf2. Two cases of mixed infections between classical and non-classical genotypic strains were recorded. CONCLUSION High genetic diversity was detected among AstVs in Lebanon. AstVs are associated with 5.5% of non-rotavirus GE-associated hospitalizations in children under five years in Lebanon.
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Detection of gastrointestinal pathogens in oncology patients by highly multiplexed molecular panels. Eur J Clin Microbiol Infect Dis 2017; 36:1665-1672. [PMID: 28429164 DOI: 10.1007/s10096-017-2981-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 04/04/2017] [Indexed: 01/05/2023]
Abstract
We compared the frequency of gastrointestinal (GI) pathogen detection in an oncology patient population by two multiplexed molecular assays, the Luminex xTAG® Gastrointestinal Pathogen Panel (GPP, which identifies 14 GI pathogens) and the BioFire Gastrointestinal Panel (BFGP, which identifies 22 GI pathogens). We additionally reviewed the clinical characteristics of patients tested with both panels. A total of 200 prospectively collected and 81 archived stool samples were tested by both panels. In the prospective cohort, the GPP and BFGP identified a pathogen in 33.5% [95% confidence interval (CI): 27.3-40.35%] and 39.6% (95% CI: 33.0%-46.6%) of samples, respectively (p = 0.25). The BFGP detected significantly more pathogens than the GPP (p = 0.038), with 21.3% of samples positive for targets only detected by the BFGP. The concordance between the assays was very good at 91.1% (κ = 0.8, 95% CI: 0.7-0.9) when considering only pathogens detected by both assays. The most frequent pathogens detected were Clostridium difficile, norovirus, Campylobacter, and Salmonella species. On the archived samples, the BFGP was positive in 92.6% of samples but detected more pathogens than the GPP (86 vs. 97, p = 0.033), including both targets unique to the BFGP and targets common to both panels. A pathogen was more frequently detected in patients with hematological malignancies than solid tumors and in ambulatory patients compared to hospitalized patients, but these differences were not statistically significant. Overall, the detection rates were similar for both the GPP and the BFGP, and the latter detected more than one pathogen in additional patients. The impact of increased detection of GI pathogens by multiplexed panels on the clinical care of oncology patients will require further investigation.
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17
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Freeman K, Tsertsvadze A, Taylor-Phillips S, McCarthy N, Mistry H, Manuel R, Mason J. Agreement between gastrointestinal panel testing and standard microbiology methods for detecting pathogens in suspected infectious gastroenteritis: Test evaluation and meta-analysis in the absence of a reference standard. PLoS One 2017; 12:e0173196. [PMID: 28253337 PMCID: PMC5333893 DOI: 10.1371/journal.pone.0173196] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 02/16/2017] [Indexed: 01/26/2023] Open
Abstract
Objective Multiplex gastrointestinal pathogen panel (GPP) tests simultaneously identify bacterial, viral and parasitic pathogens from the stool samples of patients with suspected infectious gastroenteritis presenting in hospital or the community. We undertook a systematic review to compare the accuracy of GPP tests with standard microbiology techniques. Review methods Searches in Medline, Embase, Web of Science and the Cochrane library were undertaken from inception to January 2016. Eligible studies compared GPP tests with standard microbiology techniques in patients with suspected gastroenteritis. Quality assessment of included studies used tailored QUADAS-2. In the absence of a reference standard we analysed test performance taking GPP tests and standard microbiology techniques in turn as the benchmark test, using random effects meta-analysis of proportions. Results No study provided an adequate reference standard with which to compare the test accuracy of GPP and conventional tests. Ten studies informed a meta-analysis of positive and negative agreement. Positive agreement across all pathogens was 0.93 (95% CI 0.90 to 0.96) when conventional methods were the benchmark and 0.68 (95% CI: 0.58 to 0.77) when GPP provided the benchmark. Negative agreement was high in both instances due to the high proportion of negative cases. GPP testing produced a greater number of pathogen-positive findings than conventional testing. It is unclear whether these additional ‘positives’ are clinically important. Conclusions GPP testing has the potential to simplify testing and accelerate reporting when compared to conventional microbiology methods. However the impact of GPP testing upon the management, treatment and outcome of patients is poorly understood and further studies are needed to evaluate the health economic impact of GPP testing compared with standard methods. The review protocol is registered with PROSPERO as CRD42016033320.
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Affiliation(s)
- Karoline Freeman
- Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | | | | | - Noel McCarthy
- Warwick Medical School, University of Warwick, Coventry, United Kingdom
- NIHR Health Protection Research Unit in Gastrointestinal Infections, Oxford, United Kingdom
| | - Hema Mistry
- Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Rohini Manuel
- NIHR Health Protection Research Unit in Gastrointestinal Infections, London, United Kingdom
| | - James Mason
- Warwick Medical School, University of Warwick, Coventry, United Kingdom
- * E-mail:
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Pérot P, Lecuit M, Eloit M. Astrovirus Diagnostics. Viruses 2017; 9:v9010010. [PMID: 28085120 PMCID: PMC5294979 DOI: 10.3390/v9010010] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 12/23/2016] [Accepted: 12/30/2016] [Indexed: 01/25/2023] Open
Abstract
Various methods exist to detect an astrovirus infection. Current methods include electron microscopy (EM), cell culture, immunoassays, polymerase chain reaction (PCR) and various other molecular approaches that can be applied in the context of diagnostic or in surveillance studies. With the advent of metagenomics, novel human astrovirus (HAstV) strains have been found in immunocompromised individuals in association with central nervous system (CNS) infections. This work reviews the past and current methods for astrovirus detection and their uses in both research laboratories and for medical diagnostic purposes.
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Affiliation(s)
- Philippe Pérot
- Institut Pasteur, Biology of Infection Unit, Inserm U1117, Laboratory of Pathogen Discovery, 75015 Paris, France.
- Institut Pasteur, Centre d'innovation et de Recherche Technologique (Citech), 75015 Paris, France.
| | - Marc Lecuit
- Institut Pasteur, Biology of Infection Unit, Inserm U1117, Laboratory of Pathogen Discovery, 75015 Paris, France.
- Paris Descartes University, Sorbonne Paris Cité, 75005, Paris, France.
- Necker-Enfants Malades University Hospital, Division of Infectious Diseases and Tropical Medicine, 75015 Paris, France.
| | - Marc Eloit
- Institut Pasteur, Biology of Infection Unit, Inserm U1117, Laboratory of Pathogen Discovery, 75015 Paris, France.
- Ecole Nationale Vétérinaire d'Alfort, 94700 Maisons-Alfort, France.
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Twitchell EL, Tin C, Wen K, Zhang H, Becker-Dreps S, Azcarate-Peril MA, Vilchez S, Li G, Ramesh A, Weiss M, Lei S, Bui T, Yang X, Schultz-Cherry S, Yuan L. Modeling human enteric dysbiosis and rotavirus immunity in gnotobiotic pigs. Gut Pathog 2016; 8:51. [PMID: 27826359 PMCID: PMC5100090 DOI: 10.1186/s13099-016-0136-y] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 10/20/2016] [Indexed: 01/19/2023] Open
Abstract
Background Rotavirus vaccines have poor efficacy in infants from low- and middle-income countries. Gut microbiota is thought to influence the immune response to oral vaccines. Thus, we developed a gnotobiotic (Gn) pig model of enteric dysbiosis to study the effects of human gut microbiota (HGM) on immune responses to rotavirus vaccination, and the effects of rotavirus challenge on the HGM by colonizing Gn pigs with healthy HGM (HHGM) or unhealthy HGM (UHGM). The UHGM was from a Nicaraguan infant with a high enteropathy score (ES) and no seroconversion following administration of oral rotavirus vaccine, while the converse was characteristic of the HHGM. Pigs were vaccinated, a subset was challenged, and immune responses and gut microbiota were evaluated. Results Significantly more rotavirus-specific IFN-γ producing T cells were in the ileum, spleen, and blood of HHGM than those in UHGM pigs after three vaccine doses, suggesting HHGM induces stronger cell-mediated immunity than UHGM. There were significant correlations between multiple Operational Taxonomic Units (OTUs) and frequencies of IFN-γ producing T cells at the time of challenge. There were significant positive correlations between Collinsella and CD8+ T cells in blood and ileum, as well as CD4+ T cells in blood, whereas significant negative correlations between Clostridium and Anaerococcus, and ileal CD8+ and CD4+ T cells. Differences in alpha diversity and relative abundances of OTUs were detected between the groups both before and after rotavirus challenge. Conclusion Alterations in microbiome diversity and composition along with correlations between certain microbial taxa and T cell responses warrant further investigation into the role of the gut microbiota and certain microbial species on enteric immunity. Our results support the use of HGM transplanted Gn pigs as a model of human dysbiosis during enteric infection, and oral vaccine responses. Electronic supplementary material The online version of this article (doi:10.1186/s13099-016-0136-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Erica L Twitchell
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA USA
| | - Christine Tin
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA USA
| | - Ke Wen
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA USA
| | - Husen Zhang
- Microbiome Core, Cancer Inflammation Program, National Cancer Institute, Bethesda, MD USA
| | - Sylvia Becker-Dreps
- Department of Family Medicine, University of North Carolina School of Medicine, Chapel Hill, NC USA
| | - M Andrea Azcarate-Peril
- Department of Cell Biology and Physiology, School of Medicine and Microbiome Core Facility, Center for Gastrointestinal Biology and Disease, University of North Carolina, Chapel Hill, NC USA
| | - Samuel Vilchez
- Department of Microbiology and Parasitology, Faculty of Medical Sciences, National Autonomous University of Nicaragua, León, Nicaragua
| | - Guohua Li
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA USA
| | - Ashwin Ramesh
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA USA
| | - Mariah Weiss
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA USA
| | - Shaohua Lei
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA USA
| | - Tammy Bui
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA USA
| | - Xingdong Yang
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA USA
| | - Stacey Schultz-Cherry
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN USA
| | - Lijuan Yuan
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA USA
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Point-Counterpoint: A Nucleic Acid Amplification Test for Streptococcus pyogenes Should Replace Antigen Detection and Culture for Detection of Bacterial Pharyngitis. J Clin Microbiol 2016; 54:2413-9. [PMID: 27440817 DOI: 10.1128/jcm.01472-16] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Nucleic acid amplification tests (NAATs) have frequently been the standard diagnostic approach when specific infectious agents are sought in a clinic specimen. They can be applied for specific agents such as S. pyogenes, or commercial multiplex NAATs for detection of a variety of pathogens in gastrointestinal, bloodstream, and respiratory infections may be used. NAATs are both rapid and sensitive. For many years, S. pyogenes testing algorithms used a rapid and specific group A streptococcal antigen test to screen throat specimens, followed, in some clinical settings, by a throat culture for S. pyogenes to increase the sensitivity of its detection. Now S. pyogenes NAATs are being used with increasing frequency. Given their accuracy, rapidity, and ease of use, should they replace antigen detection and culture for the detection of bacterial pharyngitis? Bobbi Pritt and Robin Patel of the Mayo Clinic, where S. pyogenes NAATs have been used for well over a decade with great success, will explain the advantages of this approach, while Richard (Tom) Thomson and Tom Kirn of the NorthShore University HealthSystem will discuss their concerns about this approach to diagnosing bacterial pharyngitis.
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The value of a multiplexed gastrointestinal pathogen panel in 2 distinct patient populations. Diagn Microbiol Infect Dis 2016; 85:105-8. [DOI: 10.1016/j.diagmicrobio.2015.12.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 12/24/2015] [Accepted: 12/26/2015] [Indexed: 11/22/2022]
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