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Stromberg ZR, Theiler J, Foley BT, Myers Y Gutiérrez A, Hollander A, Courtney SJ, Gans J, Deshpande A, Martinez-Finley EJ, Mitchell J, Mukundan H, Yusim K, Kubicek-Sutherland JZ. Fast Evaluation of Viral Emerging Risks (FEVER): A computational tool for biosurveillance, diagnostics, and mutation typing of emerging viral pathogens. PLOS GLOBAL PUBLIC HEALTH 2022; 2:e0000207. [PMID: 36962401 PMCID: PMC10021650 DOI: 10.1371/journal.pgph.0000207] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 01/23/2022] [Indexed: 12/23/2022]
Abstract
Viral pathogens can rapidly evolve, adapt to novel hosts, and evade human immunity. The early detection of emerging viral pathogens through biosurveillance coupled with rapid and accurate diagnostics are required to mitigate global pandemics. However, RNA viruses can mutate rapidly, hampering biosurveillance and diagnostic efforts. Here, we present a novel computational approach called FEVER (Fast Evaluation of Viral Emerging Risks) to design assays that simultaneously accomplish: 1) broad-coverage biosurveillance of an entire group of viruses, 2) accurate diagnosis of an outbreak strain, and 3) mutation typing to detect variants of public health importance. We demonstrate the application of FEVER to generate assays to simultaneously 1) detect sarbecoviruses for biosurveillance; 2) diagnose infections specifically caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); and 3) perform rapid mutation typing of the D614G SARS-CoV-2 spike variant associated with increased pathogen transmissibility. These FEVER assays had a high in silico recall (predicted positive) up to 99.7% of 525,708 SARS-CoV-2 sequences analyzed and displayed sensitivities and specificities as high as 92.4% and 100% respectively when validated in 100 clinical samples. The D614G SARS-CoV-2 spike mutation PCR test was able to identify the single nucleotide identity at position 23,403 in the viral genome of 96.6% SARS-CoV-2 positive samples without the need for sequencing. This study demonstrates the utility of FEVER to design assays for biosurveillance, diagnostics, and mutation typing to rapidly detect, track, and mitigate future outbreaks and pandemics caused by emerging viruses.
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Affiliation(s)
- Zachary R Stromberg
- Physical Chemistry and Applied Spectroscopy, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - James Theiler
- Space Data Science and Systems, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Brian T Foley
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Adán Myers Y Gutiérrez
- Biosecurity and Public Health, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Attelia Hollander
- Biosecurity and Public Health, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Samantha J Courtney
- Physical Chemistry and Applied Spectroscopy, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Jason Gans
- Biosecurity and Public Health, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Alina Deshpande
- Biosecurity and Public Health, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | | | - Jason Mitchell
- Presbyterian Healthcare Services, Albuquerque, New Mexico, United States of America
| | - Harshini Mukundan
- Physical Chemistry and Applied Spectroscopy, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Karina Yusim
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Jessica Z Kubicek-Sutherland
- Physical Chemistry and Applied Spectroscopy, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
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2
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SantaLucia J, Sozhamannan S, Gans JD, Koehler JW, Soong R, Lin NJ, Xie G, Olson V, Roth K, Beck L. Appendix Q: Recommendations for Developing Molecular Assays for Microbial Pathogen Detection Using Modern In Silico Approaches. J AOAC Int 2020; 103:882-899. [PMID: 33241357 PMCID: PMC8370429 DOI: 10.1093/jaoacint/qsaa045] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 03/19/2020] [Indexed: 11/13/2022]
Affiliation(s)
| | - Shanmuga Sozhamannan
- Logistics Management Institute supporting Defense Biological Product Assurance Office (DBPAO), Joint Project Leads (JPL) Chemical, Biological, Radiological, and Nuclear Defense (CBRND) Enabling Biotechnologies (EB)
| | | | - Jeffrey W Koehler
- U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID)
| | | | - Nancy J Lin
- National Institute of Standards and Technology (NIST)
| | - Gary Xie
- Los Alamos National Laboratory (LANL)
| | | | | | - Linda Beck
- Joint Research and Development, Inc. (JRAD) supporting Joint Program Executive Office (JPEO) JPL CBRND EB; Deputy Under Secretary of the Army, Test and Evaluation (DUSA TE)
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3
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Krishna MS, Wang Z, Zheng L, Bowry J, Ong AAL, Mu Y, Prabakaran M, Chen G. Incorporating G-C Pair-Recognizing Guanidinium into PNAs for Sequence and Structure Specific Recognition of dsRNAs over dsDNAs and ssRNAs. Biochemistry 2019; 58:3777-3788. [PMID: 31424191 DOI: 10.1021/acs.biochem.9b00608] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Recognition of RNAs under physiological conditions is important for the development of chemical probes and therapeutic ligands. Nucleobase-modified dsRNA-binding PNAs (dbPNAs) are promising for the recognition of dsRNAs in a sequence and structure specific manner under near-physiological conditions. Guanidinium is often present in proteins and small molecules for the recognition of G bases in nucleic acids, in cell-penetrating carriers, and in bioactive drug molecules, which might be due to the fact that guanidinium is amphiphilic and has unique hydrogen bonding and stacking properties. We hypothesized that a simple guanidinium moiety can be directly incorporated into PNAs to facilitate enhanced molecular recognition of G-C pairs in dsRNAs and improved bioactivity. We grafted a guanidinium moiety directly into a PNA monomer (designated as R) using a two-carbon linker as guided by computational modeling studies. The synthetic scheme of the PNA R monomer is relatively simple compared to that of the previously reported L monomer. We incorporated the R residue into various dbPNAs for binding studies. dbPNAs incorporated with R residues are excellent in sequence specifically recognizing G-C pairs in dsRNAs over dsDNA and ssRNAs. We demonstrated that the R residue is compatible with unmodified T and C and previously developed modified L and Q residues in dbPNAs for targeting model dsRNAs, the influenza A viral panhandle duplex structure, and the HIV-1 frameshift site RNA hairpin. Furthermore, R residues enhance the cellular uptake of PNAs.
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Affiliation(s)
- Manchugondanahalli S Krishna
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences , Nanyang Technological University , 21 Nanyang Link , Singapore 637371
| | - Zhenzhang Wang
- Temasek Life Science Laboratory, 1 Research Link, National University of Singapore , Singapore 117604
| | - Liangzhen Zheng
- School of Biological Sciences , Nanyang Technological University , Singapore 637551
| | - Jogesh Bowry
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences , Nanyang Technological University , 21 Nanyang Link , Singapore 637371.,Department of Chemistry , University of Southampton , Southampton SO17 1BJ , U.K
| | - Alan Ann Lerk Ong
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences , Nanyang Technological University , 21 Nanyang Link , Singapore 637371
| | - Yuguang Mu
- School of Biological Sciences , Nanyang Technological University , Singapore 637551
| | - Mookkan Prabakaran
- Temasek Life Science Laboratory, 1 Research Link, National University of Singapore , Singapore 117604
| | - Gang Chen
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences , Nanyang Technological University , 21 Nanyang Link , Singapore 637371
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4
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Krishna MS, Toh DFK, Meng Z, Ong AAL, Wang Z, Lu Y, Xia K, Prabakaran M, Chen G. Sequence- And Structure-Specific Probing of RNAs by Short Nucleobase-Modified dsRNA-Binding PNAs Incorporating a Fluorescent Light-up Uracil Analog. Anal Chem 2019; 91:5331-5338. [PMID: 30873827 DOI: 10.1021/acs.analchem.9b00280] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
RNAs are emerging as important biomarkers and therapeutic targets. The strategy of directly targeting double-stranded RNA (dsRNA) by triplex-formation is relatively underexplored mainly due to the weak binding at physiological conditions for the traditional triplex-forming oligonucleotides (TFOs). Compared to DNA and RNA, peptide nucleic acids (PNAs) are chemically stable and have a neutral peptide-like backbone, and thus, they show significantly enhanced binding to natural nucleic acids. We have successfully developed nucleobase-modified dsRNA-binding PNAs (dbPNAs) to facilitate structure-specific and selective recognition of dsRNA over single-stranded RNA (ssRNA) and dsDNA regions at near-physiological conditions. The triplex formation strategy facilitates the targeting of not only the sequence but also the secondary structure of RNA. Here, we report the development of novel dbPNA-based fluorescent light-up probes through the incorporation of A-U pair-recognizing 5-benzothiophene uracil (btU). The incorporation of btU into dbPNAs does not affect the binding affinity toward dsRNAs significantly, in most cases, as evidenced by our nondenaturing gel shift assay data. The blue fluorescence emission intensity of btU-modified dbPNAs is sequence- and structure-specifically enhanced by dsRNAs, including the influenza viral RNA panhandle duplex and HIV-1-1 ribosomal frameshift-inducing RNA hairpin, but not ssRNAs or DNAs, at 200 mM NaCl, pH 7.5. Thus, dbPNAs incorporating btU-modified and other further modified fluorescent nucleobases will be useful biochemical tools for probing and detecting RNA structures, interactions, and functions.
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Affiliation(s)
- Manchugondanahalli S Krishna
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences , Nanyang Technological University , 21 Nanyang Link , 637371 , Singapore
| | - Desiree-Faye Kaixin Toh
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences , Nanyang Technological University , 21 Nanyang Link , 637371 , Singapore
| | - Zhenyu Meng
- Division of Mathematical Sciences, School of Physical and Mathematical Sciences , Nanyang Technological University , 21 Nanyang Link , 637371 , Singapore
| | - Alan Ann Lerk Ong
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences , Nanyang Technological University , 21 Nanyang Link , 637371 , Singapore
| | - Zhenzhang Wang
- Temasek Life Science Laboratory , 1 Research Link, National University of Singapore , 117604 , Singapore
| | - Yunpeng Lu
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences , Nanyang Technological University , 21 Nanyang Link , 637371 , Singapore
| | - Kelin Xia
- Division of Mathematical Sciences, School of Physical and Mathematical Sciences , Nanyang Technological University , 21 Nanyang Link , 637371 , Singapore
| | - Mookkan Prabakaran
- Temasek Life Science Laboratory , 1 Research Link, National University of Singapore , 117604 , Singapore
| | - Gang Chen
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences , Nanyang Technological University , 21 Nanyang Link , 637371 , Singapore
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Schoenbrunner NJ, Gupta AP, Young KKY, Will SG. Covalent modification of primers improves PCR amplification specificity and yield. Biol Methods Protoc 2017; 2:bpx011. [PMID: 32161793 PMCID: PMC6994073 DOI: 10.1093/biomethods/bpx011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 05/31/2017] [Accepted: 11/09/2017] [Indexed: 01/01/2023] Open
Abstract
We report a method for covalent modification of primers that enhances the specificity of PCR and increases the yield of specific amplification products at the end of PCR. The introduction of thermally stable covalent modifications, such as alkyl groups to the exocyclic amines of deoxyadenosine or cytosine residues at the 3'-ends of primers results in enhanced specificity of reactions. This higher specificity can result in greater sensitivity of detection by reducing competition with non-productive reactions. The reduction in the amplification of unintended byproducts is most apparent when both primers are modified at their respective 3'-ends. The T Ms of such modified primers are only slightly affected by the inclusion of these modifiers. The principal mode of action is believed to be driven by the poor enzyme extension of substrates with closely juxtaposed bulky alkyl groups, such as would result from the replication of primer dimer artifact.
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Affiliation(s)
| | | | | | - Stephen G Will
- Research Department, Roche Molecular Systems, Inc., 4300 Hacienda Drive, Pleasanton, CA 94588, USA
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Li J, Arévalo MT, Chen Y, Chen S, Zeng M. T-cell-mediated cross-strain protective immunity elicited by prime-boost vaccination with a live attenuated influenza vaccine. Int J Infect Dis 2014; 27:37-43. [PMID: 25172265 DOI: 10.1016/j.ijid.2014.05.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 04/24/2014] [Accepted: 05/19/2014] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Antigenic drift and shift of influenza viruses require frequent reformulation of influenza vaccines. In addition, seasonal influenza vaccines are often mismatched to the epidemic influenza strains. This stresses the need for a universal influenza vaccine. METHODS BALB/c mice were vaccinated with the trivalent live attenuated (LAIV; FluMist) or inactivated (TIV; FluZone) influenza vaccines and challenged with PR8 (H1N1), FM/47 (H1N1), or HK/68 (H3N2) influenza virus. Cytokines and antibody responses were tested by ELISA. Furthermore, different LAIV dosages were applied in BALB/c mice. LAIV vaccinated mice were also depleted of T-cells and challenged with PR8 virus. RESULTS LAIV induced significant protection against challenge with the non-vaccine strain PR8 influenza virus. Furthermore, protective immunity against PR8 was dose-dependent. Of note, interleukin 2 and interferon gamma cytokine secretion in the lung alveolar fluid were significantly elevated in mice vaccinated with LAIV. Moreover, T-cell depletion of LAIV vaccinated mice compromised protection, indicating that T-cell-mediated immunity is required. In contrast, passive transfer of sera from mice vaccinated with LAIV into naïve mice failed to protect against PR8 challenge. Neutralization assays in vitro confirmed that LAIV did not induce cross-strain neutralizing antibodies against PR8 virus. Finally, we showed that three doses of LAIV also provided protection against challenge with two additional heterologous viruses, FM/47 and HK/68. CONCLUSIONS These results support the potential use of the LAIV as a universal influenza vaccine under a prime-boost vaccination regimen.
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Affiliation(s)
- Junwei Li
- Center of Excellence for Infectious Diseases, Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, 5001 El Paso Drive, El Paso, TX 79905, USA
| | - Maria T Arévalo
- Center of Excellence for Infectious Diseases, Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, 5001 El Paso Drive, El Paso, TX 79905, USA
| | - Yanping Chen
- Center of Excellence for Infectious Diseases, Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, 5001 El Paso Drive, El Paso, TX 79905, USA
| | - Shan Chen
- Center of Excellence for Infectious Diseases, Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, 5001 El Paso Drive, El Paso, TX 79905, USA
| | - Mingtao Zeng
- Center of Excellence for Infectious Diseases, Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, 5001 El Paso Drive, El Paso, TX 79905, USA.
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Abstract
Fluorescent dyes that bind DNA have been demonstrated as a useful alternative to radionucleotides for the quantification of DNA and the in vitro measurement of the activity of DNA polymerases and nucleases. However, this approach is generally used in a semi‐quantitative way to determine relative rates of reaction. In this report, we demonstrate a method for the simultaneous quantification of DNA in both its single‐strand and double‐strand forms using the dye PicoGreen. This approach is used in a steady‐state assay of DNA polymerase Klenow fragment exo−, where we determine kcat and Km values for the DNA polymerase that are in excellent agreement with literature values.
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Affiliation(s)
- Max D. Driscoll
- Manchester Institute of Biotechnology and Faculty of Life SciencesUniversity of ManchesterUK
| | - Julius Rentergent
- Manchester Institute of Biotechnology and Faculty of Life SciencesUniversity of ManchesterUK
| | - Sam Hay
- Manchester Institute of Biotechnology and Faculty of Life SciencesUniversity of ManchesterUK
- Correspondence
S. Hay, Manchester Institute of Biotechnology and Faculty of Life Sciences, University of Manchester, 131 Princess Street, Greater Manchester M1 7DN, UK
Fax: +44 0 161 306 5201
Tel: +44 0 161 306 5141
E‐mail:
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Okomo-Adhiambo M, Sheu TG, Gubareva LV. Assays for monitoring susceptibility of influenza viruses to neuraminidase inhibitors. Influenza Other Respir Viruses 2013; 7 Suppl 1:44-9. [PMID: 23279896 DOI: 10.1111/irv.12051] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Close monitoring of drug susceptibility among human influenza viruses was necessitated by widespread resistance to M2 inhibitors in influenza H1N1 (pre-pandemic and 2009 pandemic) and H3N2 viruses, and of oseltamivir resistance in pre-pandemic H1N1 viruses. The FDA-approved neuraminidase (NA) inhibitors (NAIs), oseltamivir and zanamivir, as well as investigational NAIs, peramivir and laninamivir, are currently the principal treatment options for managing influenza infection. However, there are challenges associated with assessing virus susceptibility to this class of drugs. Traditional cell culture-based assays are not reliable for phenotypic testing of NAI susceptibility due to complexity in interpretation. Two types of laboratory assays are currently available for monitoring NAI susceptibility, phenotypic such as the neuraminidase inhibition (NI) assay and genotypic. The NI assay's requirement for propagated virus lengthens testing turnaround; therefore, the need for timely detection of molecular markers associated with NAI resistance (e.g., H275Y in H1N1) has spurred the development of rapid, high-throughput assays, such as real-time RT-PCR and pyrosequencing. The high sensitivity of genotypic assays allows testing of clinical specimens thus eliminating the need for virus propagation in cell culture. The NI assays are especially valuable when a novel virus emerges or a new NAI becomes available. Modifications continue to be introduced into NI assays, including optimization and data analysis criteria. The optimal assay of choice for monitoring influenza drug susceptibility varies widely depending on the needs of laboratories (e.g., surveillance purposes, clinical settings). Optimally, it is desirable to combine functional and genetic analyses of virus isolates and, when possible, the respective clinical specimens.
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Affiliation(s)
- Margaret Okomo-Adhiambo
- Virus Surveillance and Diagnosis Branch, Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
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Pabbaraju K, Wong S, Drews SJ. Rethinking approaches to improve the utilization of nucleic acid amplification tests for detection and characterization of influenza A in diagnostic and reference laboratories. Future Microbiol 2011; 6:1443-60. [PMID: 22122441 DOI: 10.2217/fmb.11.126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Influenza A virus (IFVA) is a significant cause of respiratory infections worldwide and was also responsible for a recent pandemic in 2009. Laboratory identification of IFVA can guide antiviral therapy, assist in cohorting of patients and prevent antibiotic use. Characterization of the virus can track the emergence of novel strains, identify resistance and determine how circulating strains match with vaccine components. The gold standard for detection and characterization of IFVA is nucleic acid amplification technology (e.g., reverse transcriptase PCR [RT-PCR]), which must contend with a constantly evolving viral genome. Although molecular technology has been available for over two decades, there is still an operational gap between assay design and utilization of these tests for the diagnosis and characterization of IFVA. This review will discuss issues surrounding the implementation and use of RT-PCR for the identification and characterization of IFVA, and speculate on why RT-PCR has not been used more widely in clinical laboratories or moved closer to the patient. Newer, less widely used technologies that may change our laboratory practices will be identified and the authors will close with an attempt to identify some future applications of RT-PCR-based technologies for the detection and characterization of IFVA.
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Affiliation(s)
- Kanti Pabbaraju
- Provincial Laboratory for Public Health, Microbiology, 3030 Hospital Drive NW, Calgary, Alberta T2N 4W4, Canada
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Chan PA, Mermel LA, Andrea SB, McCulloh R, Mills JP, Echenique I, Leveen E, Rybak N, Cunha C, Machan JT, Healey TT, Chapin KC. Distinguishing characteristics between pandemic 2009-2010 influenza A (H1N1) and other viruses in patients hospitalized with respiratory illness. PLoS One 2011; 6:e24734. [PMID: 21949746 PMCID: PMC3174965 DOI: 10.1371/journal.pone.0024734] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Accepted: 08/19/2011] [Indexed: 11/29/2022] Open
Abstract
Background Differences in clinical presentation and outcomes among patients infected with pandemic 2009 influenza A H1N1 (pH1N1) compared to other respiratory viruses have not been fully elucidated. Methodology/Principal Findings A retrospective study was performed of all hospitalized patients at the peak of the pH1N1 season in whom a single respiratory virus was detected by a molecular assay targeting 18 viruses/subtypes (RVP, Luminex xTAG). Fifty-two percent (615/1192) of patients from October, 2009 to December, 2009 had a single respiratory virus (291 pH1N1; 207 rhinovirus; 45 RSV A/B; 37 parainfluenza; 27 adenovirus; 6 coronavirus; and 2 metapneumovirus). No seasonal influenza A or B was detected. Individuals with pH1N1, compared to other viruses, were more likely to present with fever (92% & 70%), cough (92% & 86%), sore throat (32% & 16%), nausea (31% & 8%), vomiting (39% & 30%), abdominal pain (14% & 7%), and a lower white blood count (8,500/L & 13,600/L, all p-values<0.05). In patients with cough and gastrointestinal complaints, the presence of subjective fever/chills independently raised the likelihood of pH1N1 (OR 10). Fifty-five percent (336/615) of our cohort received antibacterial agents, 63% (385/615) received oseltamivir, and 41% (252/615) received steroids. The mortality rate of our cohort was 1% (7/615) and was higher in individuals with pH1N1 compared to other viruses (2.1% & 0.3%, respectively; p = 0.04). Conclusions/Significance During the peak pandemic 2009–2010 influenza season in Rhode Island, nearly half of patients admitted with influenza-like symptoms had respiratory viruses other than influenza A. A high proportion of patients were treated with antibiotics and pH1N1 infection had higher mortality compared to other respiratory viruses.
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Affiliation(s)
- Philip A. Chan
- Division of Infectious Diseases, Rhode Island Hospital, Providence, Rhode Island, United States of America
- Department of Medicine, Alpert Medical School of Brown University, Providence, Rhode Island, United States of America
| | - Leonard A. Mermel
- Division of Infectious Diseases, Rhode Island Hospital, Providence, Rhode Island, United States of America
- Department of Medicine, Alpert Medical School of Brown University, Providence, Rhode Island, United States of America
| | - Sarah B. Andrea
- Department of Pathology, Rhode Island Hospital, Providence, Rhode Island, United States of America
| | - Russell McCulloh
- Division of Pediatric Infectious Diseases, Rhode Island Hospital, Providence, Rhode Island, United States of America
- Department of Pediatrics, Alpert Medical School of Brown University, Providence, Rhode Island, United States of America
| | - John P. Mills
- Department of Medicine, Alpert Medical School of Brown University, Providence, Rhode Island, United States of America
| | - Ignacio Echenique
- Department of Medicine, Alpert Medical School of Brown University, Providence, Rhode Island, United States of America
| | - Emily Leveen
- Department of Medicine, Alpert Medical School of Brown University, Providence, Rhode Island, United States of America
| | - Natasha Rybak
- Department of Medicine, Alpert Medical School of Brown University, Providence, Rhode Island, United States of America
| | - Cheston Cunha
- Department of Medicine, Alpert Medical School of Brown University, Providence, Rhode Island, United States of America
| | - Jason T. Machan
- Department of Orthopedics and Surgery, Rhode Island Hospital, Providence, Rhode Island, United States of America
| | - Terrance T. Healey
- Department of Radiology, Rhode Island Hospital, Providence, Rhode Island, United States of America
| | - Kimberle C. Chapin
- Department of Medicine, Alpert Medical School of Brown University, Providence, Rhode Island, United States of America
- Department of Pathology, Rhode Island Hospital, Providence, Rhode Island, United States of America
- * E-mail:
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12
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Tong SYC, Dakh F, Hurt AC, Deng YM, Freeman K, Fagan PK, Barr IG, Giffard PM. Rapid detection of the H275Y oseltamivir resistance mutation in influenza A/H1N1 2009 by single base pair RT-PCR and high-resolution melting. PLoS One 2011; 6:e21446. [PMID: 21731753 PMCID: PMC3123348 DOI: 10.1371/journal.pone.0021446] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Accepted: 05/27/2011] [Indexed: 11/19/2022] Open
Abstract
Introduction We aimed to design a real-time reverse-transcriptase-PCR (rRT-PCR), high-resolution melting (HRM) assay to detect the H275Y mutation that confers oseltamivir resistance in influenza A/H1N1 2009 viruses. Findings A novel strategy of amplifying a single base pair, the relevant SNP at position 823 of the neuraminidase gene, was chosen to maintain specificity of the assay. Wildtype and mutant virus were differentiated when using known reference samples of cell-cultured virus. However, when dilutions of these reference samples were assayed, amplification of non-specific primer-dimer was evident and affected the overall melting temperature (Tm) of the amplified products. Due to primer-dimer appearance at >30 cycles we found that if the cycle threshold (CT) for a dilution was >30, the HRM assay did not consistently discriminate mutant from wildtype. Where the CT was <30 we noted an inverse relationship between CT and Tm and fitted quadratic curves allowed the discrimination of wildtype, mutant and 30∶70 mutant∶wildtype virus mixtures. We compared the CT values for a TaqMan H1N1 09 detection assay with those for the HRM assay using 59 clinical samples and demonstrated that samples with a TaqMan detection assay CT>32.98 would have an H275Y assay CT>30. Analysis of the TaqMan CT values for 609 consecutive clinical samples predicted that 207 (34%) of the samples would result in an HRM assay CT>30 and therefore not be amenable to the HRM assay. Conclusions The use of single base pair PCR and HRM can be useful for specifically interrogating SNPs. When applied to H1N1 09, the constraints this placed on primer design resulted in amplification of primer-dimer products. The impact primer-dimer had on HRM curves was adjusted for by plotting Tm against CT. Although less sensitive than TaqMan assays, the HRM assay can rapidly, and at low cost, screen samples with moderate viral concentrations.
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Affiliation(s)
- Steven Y C Tong
- Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia.
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13
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Validation and diagnostic application of NS and HA gene-specific real-time reverse transcription-PCR assays for detection of 2009 pandemic influenza A (H1N1) viruses in clinical specimens. J Clin Microbiol 2011; 49:2009-11. [PMID: 21367994 DOI: 10.1128/jcm.00259-11] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Real-time reverse transcription-PCR assays specific for the nonstructural (NS) and hemagglutinin (HA) genes of the 2009 pandemic influenza A (H1N1) virus were developed and evaluated with clinical samples from infected patients. The tests are characterized by high sensitivity and specificity and performed well throughout the first year of the 2009 pandemic.
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