The use of electronic cigarettes (e-cigs) are increasing, despite very limited knowledge as to their safety and effect on the lung microbiome and inflammatory response. Work currently on-going in our laboratory suggests that both cigarettes and e-cigs may impact virulence of common lung pathogens and have an immunomodulatory effect on the airway epithelium. This study will have a clinical focus and use state-of-the-art next generation sequencing technology to compare the effect on community composition, richness and diversity of the lung microbiota in people who smoke cigarettes and e-cigarettes. Transcriptomic analysis will also be used to determine changes in phenotype, and particular emphasis will be placed on examining transcription of genes associated with virulence and antibotic resistance and correlating this with relevant clinical parameters. This 3-year project will provide extensive training in molecular biology including next-generation sequencing techniques and analysis and routine bacteriology with an important clinical focus, as part of an internationally renowned research team.