Staphylococcus aureus (S. aureus) is the most prevalent etiology of infective endocarditis (IE). The disease is characterized by challenging diagnosis, high rate of complications and poor prognosis with high mortality rates. New treatment strategies are therefore needed to improve the patient outcome. The general hypothesis for this thesis, was by regarding IE as a biofilm infection we could identify novel treatment strategies and improve the outcome of S. aureus endocarditis. 

The aim of this thesis was to establish an experimental, representative S. aureus IE model to test the hypothesis by investigating the innate host response, antibiotic efficacy and evaluate novel adjunctive treatment strategies targeting key points in the pathogenesis of IE. 

Study I, evaluated the efficacy of aminoglycoside monotherapy and the innate host response in our experimental S. aureus rat IE model. 

Study II, evaluated the effect of adjunctive hyperbaric oxygen therapy (HBOT). 

Study III, evaluated adjunctive treatment with the direct thrombin inhibitor, dabigatran.

In conclusion, this Ph.D. thesis demonstrated, by regarding IE as a biofilm infection, a successful outcome of S. aureus aortic valve endocarditis was achieved, using HBOT and dabigatran as adjunctive treatment to antibiotic.

Hans Petter Hougen, Professor, MD, DMSc