Friday 5 May 2017, 1.00PM
Speaker: Joan Geoghegan, Assistant Professor of Microbiology, Trinity College Dublin.
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The host for this seminar is Professor Jen Potts.
Staphylococcus aureus is an important opportunistic human pathogen and the leading cause of skin infection in atopic dermatitis (AD) patients. AD is a common childhood skin disease affecting more than 20% of the population in the USA and Europe. S. aureus adheres to dead flattened cells (corneocytes) and heavily colonises the skin of AD patients. There is a strong correlation between disease severity and presence of the bacterium. Elucidating the molecular basis of the interaction between S. aureus and the skin is critical to understanding pathogenesis and informing targeted therapies to reduce colonization and infection in AD patients. Our work uses primary clinical strains of S. aureus isolated frompatients to uncover factors involved in bacterial attachment to AD skin corneocytes. We found that S. aureus strains colonising AD skin lesions were from diverse clonal groupings. Strains from clonal complex 1 and 8 were more frequently isolated from AD skin than from the nasal cavity of healthy children. A protein on the surface of the bacterium called ClfB was important for attachment to corneocytes. AD strains had increased ClfB ligand binding activity compared to normal nasal carriage strains and a ClfB-deficient mutant adhered less well to corneocytes from AD patients. Bacteria expressing ClfB recognised ligands distributed over the entire corneocyte surface and novel interactions between S. aureus and corneocyte proteins were identified. This work provides new insights into the adhesive interactions between S. aureus and AD skin that facilitate the initial stages of colonisation and infection.
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