Staphylococcus aureus bacteraemia – Nationwide assessment of treatment adequacy and outcome

Abstract

To assess the treatment adequacy for Staphylococcus aureus bacteraemia (SAB) and its association with outcome on a whole population basis. All individuals ≥18 years old diagnosed with SAB in Iceland between December 1 2003 and November 30 2008 were retrospectively identified. Clinical data was collected from medical records and adequacy of antibiotic treatment based on antibiotic choice, dose, administration route and treatment duration. Empirical therapy was considered adequate in 262 of 325 (81%) SAB episodes, with no correlation to outcome. The complete antibiotic treatment was deemed adequate in 147 of 279 (53%) episodes. Among patients with complicated SAB median duration of active intravenous therapy was 14 days in those experiencing relapse compared to 30 days in patients without relapse (p = 0.03). No patient died after completing adequate treatment compared to 4 (3.0%) following inadequate therapy (p = 0.01). Despite no overall change being seen in antibiotic treatment, 30-day mortality decreased from 25.0 to 6.8% from first to last year of study (p = 0.001). Appropriate antibiotic therapy for SAB was associated with lower relapse rates and mortality. Although treatment adequacy was regarded as insufficient in half of cases, mortality of SAB in Iceland is amongst the lowest recorded. In a national study of S. aureus bacteraemia the antibiotic treatment was judged inadequate in 53% of episodes, while appropriate treatment was associated with lower relapse rate and mortality. Despite this, the mortality in Iceland is among the lowest reported.