Total Career Publications: 178 Total Citations (Google Scholar): 23,148 h-index: 80 Total Career Research Income: ~€14,500,000 PhDs Graduated (Career): 22 PhDs Graduated, Overview: Cormac Gahan graduated in 1996 with a PhD in Immunology and Microbiology from University College Cork. He has since published 167 peer-reviewed articles and book chapters in journals including PNAS, Molecular Microbiology, Infection and Immunity, Vaccine and Journal of Bacteriology. His current h-index is 80 on Google Scholar with total career citations of 23,148 (Google Scholar). Prof. Gahan led the Infectious Disease programme with Prof. Colin Hill within the APC Microbiome Institute (http://apc.ucc.ie ) from 2003-2013, lead the Bile Research Group within the APC with Dr. Susan Joyce and now is PI within the APC. His research interests focus upon host-microbe signalling in the gut mediated via microbial bile acid metabolism (see Joyce et al., PNAS, 2014; Jones et al., PNAS, 2008; Begley et al., 2005). Prof. Gahan also has a long history of research work on the foodborne pathogen Listeria monocytogenes (in collaboration with Prof. Colin Hill) resulting in a number of key papers in the area (for example see Corr et al., PNAS, 2007). Recent work has also examined the use of live L. monocytogenes and L. lactis vectors as gene and protein delivery platforms. Very recent work has examined the role of diet and dietary/microbial interventions on Colonization resistance against Listeria monocytogenes (see Las Heras et al, Microbiome, 2019; Keane et al., Gut Microbes, 2023; Cazzaniga et al. J Functional Foods, 2025)

Research Overview: My research group is dedicated to understanding the molecular interactions between bacteria and the host in the gastrointestinal tract. Our work has examined the pathogenesis of specific gut pathogens (in particular Listeria monocytogenes and Clostridiodes difficile) as well as the specific interactions that occur between gut commensals and the host organism (see Las Heras et al., Microbiome 2019; Keane et al. Gut Microbes, 2023). A complete understanding of the mechanisms governing host-pathogen interactions in the GI tract can be used to inform vaccine or DNA delivery strategies, to combat infections or to exploit the unique properties of these organisms as live vectors for the delivery of novel vaccines e.g. with Prof. Mark Tangney at the Cork Cancer Research Centre (van Pijkeren et al, 2010, Human Gene Therapy) and in collaboration with Prof. Brendan Griffin (Bahey-el-din et al., 2008, Vaccine). L. monocytogenes shares much in common with normal harmless bacteria that reside as commensals in the human GI tract. We have utilized culture-independent approaches (metagenomics) to examine one such activity (bile salt hydrolase (BSH)) that is abundant throughout the entire population of organisms in the GI tract (Jones et al., 2008, PNAS). Other work in my group (in collaboration with Dr. Susan Joyce) has demonstrated the significant physiological impact exerted by bacterial BSH activity in the gut (Joyce et al. 2014, PNAS).