Dr 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 Royal Society Wolfson Fellow and Senior Lecturer in Microbiology and Infection. Her research career has focused on understanding the molecular basis of colonisation and infection by Staphylococcus aureus. Her PhD training at Trinity College Dublin with Tim Foster involved the biochemical and biophysical characterisation of staphylococcal fibrinogen-binding proteins, carrying out part of her thesis work with Magnus Höök (Texas A&M University). This work led to a redefinition of the ligand binding site within the fibrinogen binding protein ClfA. As a postdoctoral researcher, Dr Geoghegan initiated early studies on the molecular basis of protein-mediated biofilm accumulation in S. 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.

Biomedical Science – Year 3

Joan has supervised 6 PhD students to completion to date.

The lab is interested in hearing from potential PhD students with an interest in studying the molecular aspects of bacterial colonisation and virulence.

Contact Joan by email.

Dr Geoghegan’s research focuses on understanding how Staphylococcus aureus, one of the most important human pathogens, successfully colonises and establishes invasive infection.

This involves the study of bacterial factors promoting interaction with host proteins, cells and tissues and allowing persistence in the human body. Building a better understanding of the key interactions occurring between the pathogen and host will provide an opportunity to precisely target molecular interactions to prevent and treat human 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