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Flütsch S, Wiestner F, Butticaz L, Moor D, Stölting KN. Vibrio-Sequins - dPCR-traceable DNA standards for quantitative genomics of Vibrio spp. BMC Genomics 2023; 24:375. [PMID: 37403035 DOI: 10.1186/s12864-023-09429-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 06/05/2023] [Indexed: 07/06/2023] Open
Abstract
BACKGROUND Vibrio spp. are a diverse group of ecologically important marine bacteria responsible for several foodborne outbreaks of gastroenteritis around the world. Their detection and characterization are moving away from conventional culture-based methods towards next generation sequencing (NGS)-based approaches. However, genomic methods are relative in nature and suffer from technical biases arising from library preparation and sequencing. Here, we introduce a quantitative NGS-based method that enables the quantitation of Vibrio spp. at the limit of quantification (LOQ) through artificial DNA standards and their absolute quantification via digital PCR (dPCR). RESULTS We developed six DNA standards, called Vibrio-Sequins, together with optimized TaqMan assays for their quantification in individually sequenced DNA libraries via dPCR. To enable Vibrio-Sequin quantification, we validated three duplex dPCR methods to quantify the six targets. LOQs were ranging from 20 to 120 cp/µl for the six standards, whereas the limit of detection (LOD) was ~ 10 cp/µl for all six assays. Subsequently, a quantitative genomics approach was applied to quantify Vibrio-DNA in a pooled DNA mixture derived from several Vibrio species in a proof-of-concept study, demonstrating the increased power of our quantitative genomic pipeline through the coupling of NGS and dPCR. CONCLUSIONS We significantly advance existing quantitative (meta)genomic methods by ensuring metrological traceability of NGS-based DNA quantification. Our method represents a useful tool for future metagenomic studies aiming at quantifying microbial DNA in an absolute manner. The inclusion of dPCR into sequencing-based methods supports the development of statistical approaches for the estimation of measurement uncertainties (MU) for NGS, which is still in its infancy.
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Affiliation(s)
- Sabrina Flütsch
- Swiss Federal Institute of Metrology METAS, Lindenweg 50, Bern-Wabern, 3003, Switzerland.
- Swiss Federal Institute of Metrology METAS, Campus Liebefeld, Schwarzenburgstrasse 165, Bern-Köniz, 3097, Switzerland.
| | - Fabian Wiestner
- Swiss Federal Institute of Metrology METAS, Lindenweg 50, Bern-Wabern, 3003, Switzerland
- Swiss Federal Institute of Metrology METAS, Campus Liebefeld, Schwarzenburgstrasse 165, Bern-Köniz, 3097, Switzerland
| | - Lisa Butticaz
- Federal Food Safety and Veterinary Office FSVO, Schwarzenburgstrasse 165, Bern-Köniz, 3003, Switzerland
- Swiss Federal Institute of Metrology METAS, Campus Liebefeld, Schwarzenburgstrasse 165, Bern-Köniz, 3097, Switzerland
| | - Dominik Moor
- Federal Food Safety and Veterinary Office FSVO, Schwarzenburgstrasse 165, Bern-Köniz, 3003, Switzerland
- Swiss Federal Institute of Metrology METAS, Campus Liebefeld, Schwarzenburgstrasse 165, Bern-Köniz, 3097, Switzerland
| | - Kai N Stölting
- Swiss Federal Institute of Metrology METAS, Lindenweg 50, Bern-Wabern, 3003, Switzerland.
- Swiss Federal Institute of Metrology METAS, Campus Liebefeld, Schwarzenburgstrasse 165, Bern-Köniz, 3097, Switzerland.
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Berden P, Wiederkehr RS, Lagae L, Michiels J, Stakenborg T, Fauvart M, Van Roy W. Amplification Efficiency and Template Accessibility as Distinct Causes of Rain in Digital PCR: Monte Carlo Modeling and Experimental Validation. Anal Chem 2022; 94:15781-15789. [DOI: 10.1021/acs.analchem.2c03534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Pieter Berden
- Imec, Leuven 3001, Belgium
- Department of Physics and Astronomy, KU Leuven, Leuven 3001, Belgium
- Department of Molecular and Microbial Systems, Centre of Microbial and Plant Genetics, KU Leuven, Leuven 3001, Belgium
- Center for Microbiology, Flanders Institute for Biotechnology, VIB, Leuven 3001, Belgium
| | | | - Liesbet Lagae
- Imec, Leuven 3001, Belgium
- Department of Physics and Astronomy, KU Leuven, Leuven 3001, Belgium
| | - Jan Michiels
- Department of Molecular and Microbial Systems, Centre of Microbial and Plant Genetics, KU Leuven, Leuven 3001, Belgium
- Center for Microbiology, Flanders Institute for Biotechnology, VIB, Leuven 3001, Belgium
| | | | - Maarten Fauvart
- Imec, Leuven 3001, Belgium
- Department of Molecular and Microbial Systems, Centre of Microbial and Plant Genetics, KU Leuven, Leuven 3001, Belgium
- Center for Microbiology, Flanders Institute for Biotechnology, VIB, Leuven 3001, Belgium
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Burke D, Pinheiro L, Glover ES, Moon F, Deans Z, Corner A. Between Laboratory Reproducibility of DNA Extraction from Human Blood and Fresh Frozen Tissue. J Mol Diagn 2022; 24:1041-1049. [PMID: 35835375 DOI: 10.1016/j.jmoldx.2022.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 05/29/2022] [Accepted: 06/14/2022] [Indexed: 11/27/2022] Open
Abstract
Standardization of molecular diagnostics is fundamental for effective application of genetic analyses in personalized medicine. The amount of DNA extracted from a specimen can have a significant impact on diagnostic accuracy, especially in cases where the diagnostic variant has a low concentration such as cancer. Blood and tissue samples were supplied to genetic laboratories to assess the reproducibility of extraction methodologies; DNA was extracted using participants' routine procedures and returned to the external quality assessment provider. The amount of DNA was measured by two independent analytical techniques, fluorescence intensity of intercalating dye and digital PCR; DNA quality was evaluated by DNA integrity number scores. The amount of DNA extracted varied widely between and within participants and for different blood volumes, indicating that consistent diagnostic quality is challenging even within a single test center. The median digital PCR-measured amount of DNA was on average six times higher than the intercalating dye measurements obtained in this study, indicating the possibility that the latter quantitative method may significantly underestimate the amount of DNA, thus making it not fit for purpose. Standardization of genetic diagnostic tests will require a significant improvement in the reproducibility of DNA extraction; this could be achieved if suppliers and users of DNA extraction kits validate their extraction methodology using reliable quantitative measurements or reference materials.
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Affiliation(s)
- Daniel Burke
- National Measurement Institute, Australia (NMIA), Lindfield, New South Wales, Australia.
| | - Leonardo Pinheiro
- National Measurement Institute, Australia (NMIA), Lindfield, New South Wales, Australia
| | | | - Fiona Moon
- Genomics Quality Assessment, the Department of Laboratory Medicine, The Royal Infirmary of Edinburgh, Edinburgh, United Kingdom
| | - Zandra Deans
- Genomics Quality Assessment, the Department of Laboratory Medicine, The Royal Infirmary of Edinburgh, Edinburgh, United Kingdom
| | - Adam Corner
- Bio-Rad Laboratories Ltd., Digital Biology Group, Pleasanton, California
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Taylor CR, Kiesler KM, Sturk-Andreaggi K, Ring JD, Parson W, Schanfield M, Vallone PM, Marshall C. Platinum-Quality Mitogenome Haplotypes from United States Populations. Genes (Basel) 2020; 11:genes11111290. [PMID: 33138247 PMCID: PMC7716222 DOI: 10.3390/genes11111290] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 10/26/2020] [Accepted: 10/27/2020] [Indexed: 12/14/2022] Open
Abstract
A total of 1327 platinum-quality mitochondrial DNA haplotypes from United States (U.S.) populations were generated using a robust, semi-automated next-generation sequencing (NGS) workflow with rigorous quality control (QC). The laboratory workflow involved long-range PCR to minimize the co-amplification of nuclear mitochondrial DNA segments (NUMTs), PCR-free library preparation to reduce amplification bias, and high-coverage Illumina MiSeq sequencing to produce an average per-sample read depth of 1000 × for low-frequency (5%) variant detection. Point heteroplasmies below 10% frequency were confirmed through replicate amplification, and length heteroplasmy was quantitatively assessed using a custom read count analysis tool. Data analysis involved a redundant, dual-analyst review to minimize errors in haplotype reporting with additional QC checks performed by EMPOP. Applying these methods, eight sample sets were processed from five U.S. metapopulations (African American, Caucasian, Hispanic, Asian American, and Native American) corresponding to self-reported identity at the time of sample collection. Population analyses (e.g., haplotype frequencies, random match probabilities, and genetic distance estimates) were performed to evaluate the eight datasets, with over 95% of haplotypes unique per dataset. The platinum-quality mitogenome haplotypes presented in this study will enable forensic statistical calculations and thereby support the usage of mitogenome sequencing in forensic laboratories.
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Affiliation(s)
- Cassandra R. Taylor
- Armed Forces Medical Examiner System’s Armed Forces DNA Identification Laboratory (AFMES-AFDIL), Dover Air Force Base, DE 19002, USA; (C.R.T.); (K.S.-A.); (J.D.R.)
- SNA International, LLC; Alexandria, VA 22314, USA
| | - Kevin M. Kiesler
- National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, USA; (K.M.K.); (P.M.V.)
| | - Kimberly Sturk-Andreaggi
- Armed Forces Medical Examiner System’s Armed Forces DNA Identification Laboratory (AFMES-AFDIL), Dover Air Force Base, DE 19002, USA; (C.R.T.); (K.S.-A.); (J.D.R.)
- SNA International, LLC; Alexandria, VA 22314, USA
| | - Joseph D. Ring
- Armed Forces Medical Examiner System’s Armed Forces DNA Identification Laboratory (AFMES-AFDIL), Dover Air Force Base, DE 19002, USA; (C.R.T.); (K.S.-A.); (J.D.R.)
- SNA International, LLC; Alexandria, VA 22314, USA
| | - Walther Parson
- Institute of Legal Medicine, Medical University of Innsbruck, Innsbruck 6020, Austria;
- Forensic Science Program, The Pennsylvania State University, State College, PA 16801, USA
| | - Moses Schanfield
- Department of Forensic Sciences, The George Washington University, Washington, DC 20007, USA;
| | - Peter M. Vallone
- National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, USA; (K.M.K.); (P.M.V.)
| | - Charla Marshall
- Armed Forces Medical Examiner System’s Armed Forces DNA Identification Laboratory (AFMES-AFDIL), Dover Air Force Base, DE 19002, USA; (C.R.T.); (K.S.-A.); (J.D.R.)
- SNA International, LLC; Alexandria, VA 22314, USA
- Forensic Science Program, The Pennsylvania State University, State College, PA 16801, USA
- Correspondence: ; Tel.: +1-302-346-8519
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