University College Cork




Our research is focused upon two overlapping areas of interest; (1) the gastrointestinal phase of Listeria monocytogenes infection and (2) microbe-host interactions in the gut via bile acid signaling. There has recently been a revolution in our understanding of how the gut microbiota influences the health of the host and in particular provides a barrier to infection. We are interested in understanding how Listeria monocytogenes adapts to conditions encountered in the gut (elevated bile acids, elevated osmolarity and competition for nutrients) in order to survive and infect the host.
My main collaborators in these areas are Prof. Colin Hill (School of Microbiology & APC Microbiome Institute) and Dr. Susan Joyce (School of Biochemistry and Cell Biology & APC Microbiome Institute). Much of our work is carried out within the APC Microbiome Institute ( ) a Science Foundation Ireland (SFI) funded centre of excellence that works closely with industry to investigate the role of the microbiota in health and disease. The APC Microbiome Institute provides significant support for our work programme through platforms of technical expertise and facilities that underpin work in bioinformatics, tissue culture and preclinical models.
Recent work in our lab has led to an understanding of how bacterial bile acid metabolism influences host physiological processes (Joyce et al., 2014, PNAS; Joyce et al., 2014, Gut Microbes). Work in the area of Listeria pathogenesis has highlighted gene systems that are necessary for foodborne infection (Cummins et al., 2013, Plos One; Gahan & Hill, 2014, Front Cell Infect Microbiol) and bile tolerance (Dowd et al., 2011, Infection & Immunity).

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Sub-project 2: Stress pre-adaptation and virulence potential of L.monocytogenes in the food matrix


Cormac GAHAN



  • 2011 Postgraduate Cert in Higher Education (University College Cork)

  • 1996-2002 – HRB Postdoctoral Fellow

  • 1996 PhD (University College Cork)

Professional and teaching experience

  • 2013-Present:
    Senior Lecturer, School of Pharmacy & School of Microbiology, UCC

  • 2004-2013:
    Lecturer, School of Pharmacy & School of Microbiology, UCC

  • 2002-2004:
    Lecturer Department of Microbiology, UCC

Research Interests

• Gut pathogenesis of Listeria monocytogenes
• Bile acid signaling by the microbiota
• Gastrointestinal vaccine delivery

Main publications:

  • Joyce SA, MacSharry J, Casey PG, Kinsella M, Murphy EF, Shanahan F, Hill C, Gahan CG*. 2014. Regulation of host weight gain and lipid metabolism by bacterial bile acid modification in the gut. Proc Natl Acad Sci U S A. 111(20):7421-6.

  • Pereira-Fantini PM, Lapthorne S, Joyce SA, Dellios NL, Wilson G, Fouhy F, Thomas SL, Scurr M, Hill C, Gahan CG, Cotter PD, Fuller PJ, Hardikar W, Bines JE. 2014. Altered FXR signaling is associated with bile acid dysmetabolism in short bowel syndrome-associated liver disease. J Hepatol. 61(5):1115-25

  • Cummins J, Casey PG, Joyce SA, Gahan CG*. 2013. A Mariner Transposon-Based Signature-Tagged Mutagenesis System for the Analysis of Oral Infection by Listeria monocytogenes. PLoS One. 8(9):e75437

  • Dowd G, Joyce SA, Hill C, Gahan CG*. 2011. (From the cover) Investigation of the mechanisms by which Listeria monocytogenes grows in porcine gall bladder bile. Infection & Immunity. 79(1):369-79

  • Jones BV, Begley M, Hill C, Gahan CGM*, Marchesi JR. 2008. Functional and comparative metagenomic analysis of bile salt hydrolase activity in the human gut microbiome. Proc Natl Acad Sci U S A. 105(36):13580-5.

  • Corr SC, Li Y, Riedel CU, O’Toole PW, Hill C, Gahan CGM. 2007. (From the cover) Bacteriocin production as a mechanism for the anti-infective activity of Lactobacillus salivarius UCC118. Proc. Natl. Acad. Sci. (USA). 104(18): 7617-7621.

Full publications list:


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eulogoThis project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska Curie grant agreement n° 641984

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