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Microbial volatile organic compounds - a path towards rapid non-invasive detection of wound infections

Fitzgerald, Shane (2022) Microbial volatile organic compounds - a path towards rapid non-invasive detection of wound infections. PhD thesis, Dublin City University.

Abstract
The detection of microbial volatile organic compounds (VOCs) has previously demonstrated potential as a non-invasive diagnostic tool for a variety of infectious diseases and disorders. The objectives of this thesis were to firstly, illustrate and describe the close association between microbial and clinical volatilomics; secondly, to characterise the volatilomes of key wound-associated pathogens and to explore the factors influencing their VOC emission; and finally, to demonstrate the application of VOC analysis for the detection of wound infections. Chapter 1 of this report is a review of past and current literature surrounding the field of microbial and clinical volatilomics. The most common experimental methods used across microbial and clinical volatilomic studies are discussed with the aim of highlighting the critical need for standardization of these techniques across the field. This chapter finally illustrates the close association between microbial VOCs and disease and describes potential opportunities for clinical applications in the future. Chapter 2 describes the comprehensive in vitro volatilomic profiling of prevalent wound-associated bacterial pathogens. In this work, species- and strain-level volatilomic diversity were explored by utilizing a simple experimental workflow coupled with robust multivariate analysis techniques. Temporal stability of microbial VOC emissions was also investigated and measured against to cell growth. Chapter 3 was a further investigation of these pathogens. The aims of this study were to examine the influence of different nutritional media on the VOC output of the bacterial pathogens and to investigate strain-level volatilomic differences in VOC emission kinetics. In Chapter 4, the focus of investigation was shifted to fungal pathogens to characterise the factors surrounding VOC emission in multiple Candida species. In this work, volatile metabolites from 10 clinical strains of planktonic C. parapsilosis and one strain of planktonic C. albicans were profiled. The effect of biofilm formation on the C. parapsilosis volatilomes was investigated for the first time by comparing volatilomes of a biofilm-positive strain and a biofilm-negative strain over time using a novel sampling approach. In the final chapter of this thesis, our rapid noninvasive experimental workflow was employed for the analysis of wound swab samples. 23 participants (26 wounds total, 15 infected; 11 non-infected) were included in this work. The volatilomes of infected and non-infected wound samples are characterised and compoundlevel differences between them are described in this chapter. The results of this ongoing work provide clear insight into the potential of volatilomics for future clinical applications. Overall this collective work demonstrates the close association between microbial and clinical volatilomics and highlights the clear potential for volatilomics to be used for clinical diagnoses of wound infections. This thesis concludes with a short discussion of the future outlook of this work.
Metadata
Item Type:Thesis (PhD)
Date of Award:September 2022
Refereed:No
Supervisor(s):Morrin, Aoife and Holland, Linda
Subjects:Medical Sciences > Infection
Physical Sciences > Organic chemistry
DCU Faculties and Centres:DCU Faculties and Schools > Faculty of Science and Health > School of Chemical Sciences
Research Institutes and Centres > National Centre for Sensor Research (NCSR)
Research Institutes and Centres > INSIGHT Centre for Data Analytics
Funders:Science Foundation Ireland
ID Code:27700
Deposited On:17 Nov 2022 12:53 by Aoife Morrin . Last Modified 17 Nov 2022 12:53
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