Professor Joan Geoghegan BA, PhD

• PG Diploma in Educational Studies (Higher Education), Trinity College Dublin
• PhD in Microbiology, Trinity College Dublin
• BA (Hons) in Natural Sciences, Trinity College Dublin

Joan Geoghegan is a Professor of Microbiology and Infection and a Royal Society Wolfson Fellow. Since 2024 she has been Head of Department of Microbes, Infection and Microbiomes. Her research career has focused on understanding the molecular basis of colonisation and infection by Staphylococcus aureus. In 2012 she established her research group studying staphylococcal pathogenesis at Trinity College Dublin and in 2020 she was appointed to the Institute of Microbiology and Infection at the University of Birmingham.

Her research focuses on defining bacterial factors underlying the success of Staphylococcus aureus as a human pathogen. She is interested in elucidating mechanisms used by the bacterium to interact with host proteins and cells and to resist clearance by the immune system and interference from other microbes. A major aim of this work is to identify new targets for the treatment and prevention of bacterial infection.

Biomedical Science – Year 3

Molecular aspects of bacterial colonisation and virulence.

Staphylococcus aureus, MRSA, bacterial cell surfaces, skin microbiome, bacterial adhesion, antimicrobial resistance, AMR, vaccines, bacterial pathogenesis, host-pathogen interactions, atopic dermatitis.

Joan Geoghegan’s research focuses on understanding how Staphylococcus aureus, one of the most important human pathogens, successfully colonises and establishes invasive infection. Key areas of investigation include:

The molecular basis of colonisation. The human nose is the main site of asymptomatic colonisation in healthy humans with colonisation being a major risk factor for infection. Our research aims to further fundamental knowledge of the mechanisms used by S. aureus to persist in the nasal cavity. The other colonisation niche we investigate is the skin’s stratum corneum, particularly atopic dermatitis skin lesions which are particularly susceptible to colonisation and infection by S. aureus. We are investigating how bacteria interact with host corneocytes and how this influences skin colonisation.

The impact of copper hypertolerance systems on fitness and antimicrobial resistance. Epidemic strains of methicillin resistant S. aureus (MRSA) possess copper hypertolerance genes (CHGs) that detoxify copper. These are located on the same mobile genetic elements as antimicrobial resistance genes. We aim to understand how CHGs impact MRSA colonisation and pathogenesis and to determine the potential for copper to promote acquisition and retention of antimicrobial resistance genes.

The mechanistic basis of biofilm formation. Growing as biofilm communities on catheters, heart valves and artificial joints, bacteria avoid being killed by antibiotics and the human immune system. We are investigating the molecular basis of protein-mediated biofilm formation in MRSA and strategies to target the protein linkages that hold bacteria together in a biofilm.

Mechanisms of ligand binding by cell-wall anchored proteins. We are interested in understanding the ligand binding activity of cell wall-anchored proteins at the molecular level, as well as uncovering how this activity is modulated in the complex infection milieu

• Member of the Microbiology Society Scientific Conferences Panel
• Member of the Microbiology Society Building Communities Committee
• Chair of the Irish Division of Microbiology Society
• Member of the 'State of Microbiology' expert working group of Microbiology Society surveying and analysing the current landscape of microbiology education and research in the UK and Ireland
• Member of the Society for Applied Microbiology
• Member of the American Society for Microbiology