Assessment of an ex vivo porcine lung model to investigate host-microbe interactions in cases of ventilator associated pneumonia

Barber, EA

Abstract

VAP is described as a pneumonic lung infection afflicting those that have been mechanically ventilated typically with an endotracheal tube. Unfortunately, there is no singular diagnostic test for VAP (Grossman & Fein, 2000) or ‘gold standard’ for the identification and diagnosis of the disease (American Thoracic Society; Infectious diseases Society of America, 2005). Since working with patients within hospitals is unpractical for research for several reasons, a developmental ex vivo porcine lung model has been theorised. The benefits of this model include immune similarities to humans and the availability of the tissue since it is normally food waste from an abattoir (Harrison, Muruli, Higgins, & Diggle, 2014). Using this model, the primary aims of this study were; to optimise the killing methodology of excised porcine lung tissue which acts as a control comparison to viable tissue highlighting the hots-microbe interactions, to establish a routine method of taking a BAL sample from the porcine lungs to therefore identify the normal microbial constituents within the porcine lungs, to establish the cell structures communally present within the lung tissue in health and to develop a time scale of the growth of a VAP clinical isolate on inoculated ex vivo porcine lung tissue. The results indicated that cold killing was the optimal method to kill porcine lung tissue whilst also maintaining cellular structural integrity to later investigate histological structures. A basic BAL sampling method was developed which allows for future developments, however, several different bacterial species within the lungs were identified. The inoculated ex vivo porcine lung tissue CFU growth curve demonstrated that the live inoculated tissue had a larger CFU than the dead inoculated tissue, suggesting that the method of killing was successful in ‘knocking out’ the host biome. In conclusion the ex vivo porcine lung model was further developed from previous studies and results indicated that it is a practical method of exploring the hoist microbe interactions in cases of VAP.

Citation

Barber, E. (in press). Assessment of an ex vivo porcine lung model to investigate host-microbe interactions in cases of ventilator associated pneumonia. (Dissertation). University of Salford

• Thesis Type: Dissertation
• Acceptance Date: Aug 17, 2021
• Deposit Date: Oct 15, 2021
• Publicly Available Date: Oct 15, 2021
• Award Date: Aug 17, 2021