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Charles M, Ruszkiewicz D, Eckbo E, Bryce E, Zurberg T, Meister A, Aksu L, Navas L, Myers R. The science behind the nose: correlating volatile organic compound characterisation with canine biodetection of COVID-19. ERJ Open Res 2024; 10:00007-2024. [PMID: 38770004 PMCID: PMC11103684 DOI: 10.1183/23120541.00007-2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 02/20/2024] [Indexed: 05/22/2024] Open
Abstract
Background The SARS-CoV-2 pandemic stimulated the advancement and research in the field of canine scent detection of COVID-19 and volatile organic compound (VOC) breath sampling. It remains unclear which VOCs are associated with positive canine alerts. This study aimed to confirm that the training aids used for COVID-19 canine scent detection were indeed releasing discriminant COVID-19 VOCs detectable and identifiable by gas chromatography (GC-MS). Methods Inexperienced dogs (two Labradors and one English Springer Spaniel) were trained over 19 weeks to discriminate between COVID-19 infected and uninfected individuals and then independently validated. Getxent tubes, impregnated with the odours from clinical gargle samples, used during the canines' maintenance training process were also analysed using GC-MS. Results Three dogs were successfully trained to detect COVID-19. A principal components analysis model was created and confirmed the ability to discriminate between VOCs from positive and negative COVID-19 Getxent tubes with a sensitivity of 78% and a specificity of 77%. Two VOCs were found to be very predictive of positive COVID-19 cases. When comparing the dogs with GC-MS, F1 and Matthew's correlation coefficient, correlation scores of 0.69 and 0.37 were observed, respectively, demonstrating good concordance between the two methods. Interpretation This study provides analytical confirmation that canine training aids can be safely and reliably produced with good discrimination between positive samples and negative controls. It is also a further step towards better understanding of canine odour discrimination of COVID-19 as the scent of interest and defining what VOC elements the canines interpret as "essential".
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Affiliation(s)
- Marthe Charles
- Division of Medical Microbiology, Vancouver Coastal Health, Vancouver, BC, Canada
- University of British Columbia, Faculty of Medicine, Vancouver, BC, Canada
| | - Dorota Ruszkiewicz
- University of British Columbia, Faculty of Medicine, Vancouver, BC, Canada
- British Columbia Cancer Research Institute, Vancouver, BC, Canada
| | - Eric Eckbo
- Division of Medical Microbiology, Vancouver Coastal Health, Vancouver, BC, Canada
- University of British Columbia, Faculty of Medicine, Vancouver, BC, Canada
| | - Elizabeth Bryce
- Division of Medical Microbiology, Vancouver Coastal Health, Vancouver, BC, Canada
- Quality and Patient Safety, Vancouver Coastal Health, Vancouver, BC, Canada
| | - Teresa Zurberg
- Quality and Patient Safety, Vancouver Coastal Health, Vancouver, BC, Canada
| | - Austin Meister
- University of British Columbia, Faculty of Medicine, Vancouver, BC, Canada
| | - Lâle Aksu
- Quality and Patient Safety, Vancouver Coastal Health, Vancouver, BC, Canada
| | - Leonardo Navas
- Quality and Patient Safety, Vancouver Coastal Health, Vancouver, BC, Canada
| | - Renelle Myers
- University of British Columbia, Faculty of Medicine, Vancouver, BC, Canada
- British Columbia Cancer Research Institute, Vancouver, BC, Canada
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McCartney MM, Borras E, Rojas DE, Hicks TL, Hamera KL, Tran NK, Tham T, Juarez MM, Lopez E, Kenyon NJ, Davis CE. Predominant SARS-CoV-2 variant impacts accuracy when screening for infection using exhaled breath vapor. COMMUNICATIONS MEDICINE 2022; 2:158. [PMID: 36482179 PMCID: PMC9731983 DOI: 10.1038/s43856-022-00221-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 11/21/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND New technologies with novel and ambitious approaches are being developed to diagnose or screen for SARS-CoV-2, including breath tests. The US FDA approved the first breath test for COVID-19 under emergency use authorization in April 2022. Most breath-based assays measure volatile metabolites exhaled by persons to identify a host response to infection. We hypothesized that the breathprint of COVID-19 fluctuated after Omicron became the primary variant of transmission over the Delta variant. METHODS We collected breath samples from 142 persons with and without a confirmed COVID-19 infection during the Delta and Omicron waves. Breath samples were analyzed by gas chromatography-mass spectrometry. RESULTS Here we show that based on 63 exhaled compounds, a general COVID-19 model had an accuracy of 0.73 ± 0.06, which improved to 0.82 ± 0.12 when modeling only the Delta wave, and 0.84 ± 0.06 for the Omicron wave. The specificity improved for the Delta and Omicron models (0.79 ± 0.21 and 0.74 ± 0.12, respectively) relative to the general model (0.61 ± 0.13). CONCLUSIONS We report that the volatile signature of COVID-19 in breath differs between the Delta-predominant and Omicron-predominant variant waves, and accuracies improve when samples from these waves are modeled separately rather than as one universal approach. Our findings have important implications for groups developing breath-based assays for COVID-19 and other respiratory pathogens, as the host response to infection may significantly differ depending on variants or subtypes.
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Affiliation(s)
- Mitchell M McCartney
- Mechanical and Aerospace Engineering, UC Davis, Davis, CA, USA
- UC Davis Lung Center, Davis, CA, USA
- VA Northern California Health Care System, Mather, CA, USA
| | - Eva Borras
- Mechanical and Aerospace Engineering, UC Davis, Davis, CA, USA
- UC Davis Lung Center, Davis, CA, USA
| | - Dante E Rojas
- Mechanical and Aerospace Engineering, UC Davis, Davis, CA, USA
- UC Davis Lung Center, Davis, CA, USA
| | - Tristan L Hicks
- Mechanical and Aerospace Engineering, UC Davis, Davis, CA, USA
- UC Davis Lung Center, Davis, CA, USA
| | - Katherine L Hamera
- Mechanical and Aerospace Engineering, UC Davis, Davis, CA, USA
- UC Davis Lung Center, Davis, CA, USA
| | - Nam K Tran
- Department of Pathology and Laboratory Medicine, UC Davis, Sacramento, CA, USA
| | - Tina Tham
- Department of Internal Medicine, UC Davis, Sacramento, CA, USA
| | - Maya M Juarez
- Department of Internal Medicine, UC Davis, Sacramento, CA, USA
| | | | - Nicholas J Kenyon
- UC Davis Lung Center, Davis, CA, USA
- VA Northern California Health Care System, Mather, CA, USA
- Department of Internal Medicine, UC Davis, Sacramento, CA, USA
| | - Cristina E Davis
- Mechanical and Aerospace Engineering, UC Davis, Davis, CA, USA.
- UC Davis Lung Center, Davis, CA, USA.
- VA Northern California Health Care System, Mather, CA, USA.
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Sukul P, Trefz P, Schubert JK, Miekisch W. Advanced setup for safe breath sampling and patient monitoring under highly infectious conditions in the clinical environment. Sci Rep 2022; 12:17926. [PMID: 36289276 PMCID: PMC9606119 DOI: 10.1038/s41598-022-22581-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 10/17/2022] [Indexed: 01/20/2023] Open
Abstract
Being the proximal matrix, breath offers immediate metabolic outlook of respiratory infections. However, high viral load in exhalations imposes higher transmission risk that needs improved methods for safe and repeatable analysis. Here, we have advanced the state-of-the-art methods for real-time and offline mass-spectrometry based analysis of exhaled volatile organic compounds (VOCs) under SARS-CoV-2 and/or similar respiratory conditions. To reduce infection risk, the general experimental setups for direct and offline breath sampling are modified. Certain mainstream and side-stream viral filters are examined for direct and lab-based applications. Confounders/contributions from filters and optimum operational conditions are assessed. We observed immediate effects of infection safety mandates on breath biomarker profiles. Main-stream filters induced physiological and analytical effects. Side-stream filters caused only systematic analytical effects. Observed substance specific effects partly depended on compound's origin and properties, sampling flow and respiratory rate. For offline samples, storage time, -conditions and -temperature were crucial. Our methods provided repeatable conditions for point-of-care and lab-based breath analysis with low risk of disease transmission. Besides breath VOCs profiling in spontaneously breathing subjects at the screening scenario of COVID-19/similar test centres, our methods and protocols are applicable for moderately/severely ill (even mechanically-ventilated) and highly contagious patients at the intensive care.
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Affiliation(s)
- Pritam Sukul
- grid.10493.3f0000000121858338Rostock Medical Breath Research Analytics and Technologies (ROMBAT), Department of Anaesthesiology and Intensive Care, University Medicine Rostock, Schillingallee 35, 18057 Rostock, Germany
| | - Phillip Trefz
- grid.10493.3f0000000121858338Rostock Medical Breath Research Analytics and Technologies (ROMBAT), Department of Anaesthesiology and Intensive Care, University Medicine Rostock, Schillingallee 35, 18057 Rostock, Germany
| | - Jochen K. Schubert
- grid.10493.3f0000000121858338Rostock Medical Breath Research Analytics and Technologies (ROMBAT), Department of Anaesthesiology and Intensive Care, University Medicine Rostock, Schillingallee 35, 18057 Rostock, Germany
| | - Wolfram Miekisch
- grid.10493.3f0000000121858338Rostock Medical Breath Research Analytics and Technologies (ROMBAT), Department of Anaesthesiology and Intensive Care, University Medicine Rostock, Schillingallee 35, 18057 Rostock, Germany
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Ruszkiewicz DM, Myers R, Henderson B, Dato-Haji-Md-Yusof H, Meister A, Moreno S, Eddleston M, Darnley K, Nailon W, McLaren D, Lao YE, Hovda KE, Lam S, Cristescu SM, Thomas CLP. Peppermint protocol: first results for gas chromatography-ion mobility spectrometry. J Breath Res 2022; 16. [PMID: 35508103 DOI: 10.1088/1752-7163/ac6ca0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 05/04/2022] [Indexed: 11/11/2022]
Abstract
The Peppermint Initiative seeks to inform the standardisation of breath analysis methods. Five Peppermint Experiments with gas chromatography-ion mobility spectrometry (GC-IMS), operating in the positive mode with a tritium 3H 5.68 keV, 370 MBq ionisation source, were undertaken to provide benchmark Peppermint Washout data for this technique, to support its use in breath-testing, analysis, and research. Headspace analysis of a peppermint-oil capsule by GC-IMS with on-column injection (0.5 cm3) identified 12 IMS responsive compounds, of which the four most abundant were: eucalyptol; β-pinene; α-pinene; and limonene. Elevated concentrations of these four compounds were identified in exhaled-breath following ingestion of a peppermint-oil capsule. An unidentified compound attributed as a volatile catabolite of peppermint-oil was also observed. The most intense exhaled peppermint-oil component was eucalyptol, which was selected as a peppermint marker for benchmarking GC-IMS. Twenty-five washout experiments monitored levels of exhaled eucalyptol, by GC-IMS with on-column injection (0.5 cm3), at t=0 min, and then at t+60, t+90, t+165, t+285 and t+360 min from ingestion of a peppermint capsule resulting in 148 peppermint breath analyses. Additionally, the Peppermint Washout data was used to evaluate clinical deployments with a further five washout tests run in clinical settings generating an additional 35 breath samples. Regression analysis yielded an average extrapolated time taken for exhaled eucalyptol levels to return to baseline values to be 429 ± 62 min (± 95% confidence-interval). The benchmark value was assigned to the lower 95 % confidence-interval, 367 min. Further evaluation of the data indicated that the maximum number of volatile organic compounds (VOC) discernible from a 0.5 cm3 breath sample was 69, while the use of an in-line biofilter appeared to reduce this to 34.
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Affiliation(s)
- Dorota M Ruszkiewicz
- Department of Chemistry, , Loughborough University School of Science, Centre for Analytical Science, Loughborough, Leicestershire, LE11 3TU, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Renelle Myers
- British Columbia Cancer Research Centre, University of British Columbia, Vancouver, British Columbia, V5Z 1L3, CANADA
| | - Ben Henderson
- Department of Analytical Chemistry and Chemometrics, Radboud Universiteit, Institute of Molecules and Materials, Nijmegen, 6500 HC, NETHERLANDS
| | - Hazim Dato-Haji-Md-Yusof
- Department of Chemistry, , Loughborough University School of Science, Centre for Analytical Science, Loughborough, Leicestershire, LE11 3TU, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Austin Meister
- British Columbia Cancer Research Centre, University of British Columbia, Vancouver, British Columbia, V5Z 1L3, CANADA
| | - Sergi Moreno
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Michael Eddleston
- Pharmacology, Toxicology and Therapeutics Unit, University of Edinburgh Division of Clinical and Surgical Sciences, Centre for Cardiovascular Science, Edinburgh, Scotland, EH16 4TJ, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Kareen Darnley
- Royal Infirmary of Edinburgh, Wellcome Trust Clinical Research Facility, Edinburgh, Edinburgh, EH16 4SA, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - William Nailon
- Edinburgh Cancer Research Centre, Western General Hospital, Edinburgh, Scotland, EH4 2XU, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Duncan McLaren
- Edinburgh Cancer Research Centre, Western General Hospital, Edinburgh, Scotland, EH4 2XU, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Yvonne Elisabeth Lao
- Oslo University Hospital, Norwegian National Unit for CBRNE Medicine, Oslo, 20 0372, NORWAY
| | - Knut Erik Hovda
- Oslo University Hospital, Norwegian National Unit for CBRNE Medicine, Oslo, 20 0372, NORWAY
| | - Stephen Lam
- British Columbia Cancer Research Centre, University of British Columbia, Vancouver, British Columbia, V5Z 1L3, CANADA
| | - Simona M Cristescu
- Department of Analytical Chemistry and Chemometrics, Radboud Universiteit, Institute of Molecules and Materials, Nijmegen, Gelderland, 6500 HC, NETHERLANDS
| | - C L Paul Thomas
- Department of Chemistry, Loughborough University School of Science, Centre for Analytical Science, Loughborough, Leicestershire, LE11 3TU, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
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