The diagnostic use of metabolomics for the identification of secondary infections in critical coronavirus disease 2019

McCreath, Gordan (2025) The diagnostic use of metabolomics for the identification of secondary infections in critical coronavirus disease 2019. MD thesis, University of Glasgow.

Abstract

Background:
Critically ill patients with coronavirus disease 2019 are at high risk of developing secondary infections, which pose a challenge to identify clinically. Empirical antibiotic usage in this group is therefore high. Identification of novel biomarkers of secondary infections would minimise unnecessary antibiotic usage while ensuring that patients with secondary infections receive appropriate antibiotics as early as possible. This project aimed to investigate whether metabolomics could produce a panel of biomarkers capable of distinguishing critically ill coronavirus disease 2019 patients with and without secondary infections.

Methods:
Blood samples were collected from patients in critical care with coronavirus disease 2019, along with a group of healthy volunteer controls. Using high performance liquid chromatography-mass spectrometry, metabolites which showed significant differences in abundance between patients with and without secondary infections were identified. A panel of metabolites capable of distinguishing Gram positive and negative infections was also explored.

Results:
A total of 105 patients were recruited to the study, of whom 40 developed a secondary infection during the trial period. The metabolites creatine and 2-hydroxyisovalerylcarnitine were significantly increased in patients with secondary infections, while S-methyl-L-cysteine was significantly reduced. This metabolite panel demonstrated good diagnostic performance with an AUROC of 0.83. The panel of metabolites distinguishing Gram positive and negative infections consisted of betaine, N(6)-methyllysine and four phosphatidylcholines. This panel performed with high accuracy, with an AUROC of 0.88.

Conclusion:
Metabolomic profiling may be used to identify biomarkers of secondary infections in critically ill coronavirus disease 2019 patients. Investigation of biomarkers for secondary infections in other critical illnesses should be explored.

• Item Type: Thesis (MD)
• Qualification Level: Doctoral
• Subjects: Q Science > QR Microbiology; Q Science > QR Microbiology > QR180 Immunology; R Medicine > RA Public aspects of medicine
• Colleges/Schools: College of Medical Veterinary and Life Sciences > School of Infection & Immunity
• Supervisor's Name: Roe, Professor Andy, Sim, Professor Malcolm and Watson, Dr. Malcolm
• Date of Award: 2025
• Depositing User: Theses Team
• Unique ID: glathesis:2025-85418
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 27 Aug 2025 08:11
• Last Modified: 27 Aug 2025 08:16
• Thesis DOI: 10.5525/gla.thesis.85418
• URI: https://theses.gla.ac.uk/id/eprint/85418

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