Date of Award


Document type


Degree Name

MD (Medical Doctor)

First Supervisor

Professor Fergal N.G. McElvaney


Health Research Board, Science Foundation Ireland, Irish Thoracic Society, Allen and Hannbury.


Anaerobic Bacteria, Cystic Fibrosis, Lung Disease.


Recurrent bacterial infections in Cystic Fibrosis (CF) are the primary cause for morbidity and mortality in CF. Advancements in second generation sequencing and evolution of the lung microbiome has prompted greater interest in other bacteria present in the lung. Anaerobic bacteria have been one of the most common bacteria found on molecular sequencing, their cause and role is as of yet unknown. In our project, we recruited 450 patients prospectively and followed them at both stable and exacerbation timepoints. Their sputum and BAL was cultured and sequenced from both adults and children. The most prevalent bacteria found, Prevotella me/aninogenicawas found to produce proteases that inhibited naturally occurring defensins and anti-microbial peptides and the short chain acids produced by these bacteria were shown to have a pro-inflammatory effect. This provides evidence that certain anaerobic bacteria are pathogenic and these bacteria should be more directly targeted against during an exacerbation.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 4.0 License.

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A thesis submitted for the degree of Doctor of Medicine from the Royal College of Surgeons in Ireland in 2014.