Treatment of Complicated Gram-Positive Bacteremia and Infective Endocarditis

The Gram-positive cocci Staphylococcus aureus, Streptococcus spp., and Enterococcus spp. are the most frequent causative organisms of bloodstream infections and infective endocarditis. "Complicated bacteremia" is a term used in S. aureus bloodstream infections and originally implied the presence of metastatic infectious foci (i.e. complications of S. aureus bacteremia). These complications demand longer antimicrobial treatment durations and, frequently, interventional source control. Several risk factors for the incidence of bacteremia complications have been identified and are often used for the definition of complicated bacteremia. Here, we discuss management and diagnostic approaches and treatment options for patients with complicated bacteremia, with particular focus on infective endocarditis. We also summarize the available evidence regarding imaging modalities and the choice of antimicrobial mono- or combination therapy according to resistance patterns for these pathogens as well as treatment durations and optimized application routes. Finally, we synopsize current and future areas of research in complicated bacteremia and infective endocarditis.