Morais, Elisabete Cristina Cordeiro2026-05-062026-05-062026-03-20http://hdl.handle.net/10362/202884"Staphylococcus epidermidis is a common human skin coloniser and an opportunistic pathogen related with medical device-associated infections. It presents a dual lifestyle and, according to phylogenetic studies, S. epidermidis strains are grouped into two main lineages: B, composed mainly of isolates colonising skin, and A/C, composed equally of skin-colonising and nosocomial infection isolates. Understanding metabolic and biological features associated with each lineage’s pathogenic and commensal phenotypes is crucial for developing targeted prevention and treatment strategies against S. epidermidis infections. The increased prevalence of S. epidermidis infections, together with the emergence of multidrug-resistant strains, underscores the need for those strategies. This thesis presents comparative studies addressing the metabolic and biological responses of different strains under relevant biological conditions, including pH and the presence of fatty acids. Two phylogenetically distinct strains were selected for comparative analysis: ICE25, belonging to the A/C lineage and representing a strain of higher pathogenic potential, and 19N, from the B lineage and representing a commensal strain.(...)"engStaphylococcus epidermidispathogenicitycommensalismenvironmental pHtime course exometabolomics1H NMRgenome-scale metabolic modelspan-metabolic networkantimicrobial endogenous fatty aciddoctoral thesis