Culture-based determinants and outcome of Staphylococcus aureus bloodstream infections

Abstract

The objective of this study was to examine the occurrence, determinants, and outcome of S. aureus bloodstream infections (BSI) diagnosed based on single versus multiple positive initial cultures. All adults with first episodes of mono-microbial S. aureus BSI in Queensland during 2000-2019 were included. 10,855 (67%) and 5,421 (33%) were diagnosed based on one and multiple positive initial cultures, respectively. Patients with multiple positive initial cultures were significantly younger, more likely to have community-associated disease, have a shorter time to culture positivity, less likely to have methicillin-resistant S. aureus BSI, and have a different distribution of comorbid medical illnesses and clinical foci. The 30-day all-cause case-fatality rate was 18% and single positive initial culture was an independent risk factor for death. Among patients with S. aureus BSI, those diagnosed by single positive initial blood cultures have different clinical features and a higher risk for death.