Complicated and uncomplicated S. aureus bacteraemia: an international Delphi survey among infectious diseases experts on definitions and treatment

Classification of Staphylococcus aureus bacteraemia (SAB) as 'complicated' or 'uncomplicated' and management of both is based on low-quality evidence. The aim of the study was to determine the degree of agreement among infectious diseases physician experts in the management of patients with SAB.A stepwise RAND-modified Delphi procedure with two questionnaire rounds was performed. Four aspects of management in 22 clinical scenarios were addressed: (a) classification of SAB episodes; (b) value of combination therapy; and (c) timing of and (d) preferred antibiotics for oral stepdown therapy.Out of 90 approached experts, 33 (36.7%) from 14 different countries and 5 continents consented to participate. The experts considered any of the discussed implanted foreign material (with no evidence of infection), except for coronary artery stents, as relevant to the classification of a complicated SAB episode. Concerning antibiotic combination therapy, the experts strongly agreed that combination therapy with rifampicin is only relevant in patients with prosthetic valve endocarditis and prosthetic joint infection. The experts considered an oral stepdown therapy in patients with an uncomplicated SAB within 14 days and only thereafter in patients with a complicated SAB episode, but never in patients with prosthetic valve endocarditis. No single antibiotic of choice for oral stepdown therapy could be identified, neither for infections with methicillin-resistant S. aureus nor methicillin-susceptible S. aureus.The Delphi survey can help physicians in their day-to-day decision-making process, and it reveals open questions that must be investigated by further studies.