A prospective observational cohort study of hospitalised patients with Staphylococcus aureus (S. aureus) bacteraemia suggests redefining the cut-off duration for persistent bacteraemia.
The analysis, published in Lancet Infectious Diseases, included 987 patients who were hospitalised with monomicrobial S. aureus bacteraemia across 17 European centres. The primary outcome was 90-day mortality, and the duration of bacteraemia was defined as bacteraemic days under active antibiotic therapy.
The 90-day mortality increased from 22 per cent with one day of bacteraemia to 39 per cent with 2-4 days, 43 per cent with 5-7 days, and 36 per cent with more than seven days of bacteraemia. The researchers found that the second day of bacteraemia under antibiotic therapy represented the most pronounced and earliest cut-off to differentiate between patients who survived and those who died.
These results suggest that taking follow-up cultures earlier than the recommended 48-72 hour interval would help to identify more patients with an increased risk of mortality, and allow earlier assessment of additional diagnostic and therapeutic measures.
The study authors suggest defining the duration of bacteraemia as the number of days of bacteraemia from the start of active antibiotic treatment until last positive blood culture.