Relationship between blood culture time to positivity, mortality rate, and severity of bacteremia.

Objectives: We investigated the association between patient severity or mortality and time to positivity in bacteremia caused by various pathogens.

Patients And Methods: This single-center retrospective study included patients with positive blood culture results.

Results: Longer time to positivity was associated with 30-day mortality for Staphylococcus aureus (221 cases, time to positivity: 17.4 h in the 30-day mortality group vs. 14.1 h in the survival group). Age, chronic kidney disease, cerebrovascular disease, hypertensive drug use, consciousness disorder, and minimal systolic blood pressure were significant predictors of 30-day mortality. For S. aureus, mortality within 30 days was significantly higher when time to positivity was > 24 h (p = 0.04). The time to positivity of Streptococcus pneumoniae, α, β-hemolytic Streptococcus, Enterococcus sp., Enterobacteriaceae, glucose-nonfermenting Gram-negative rods, Candida sp., and anaerobe was not significantly associated with 30-day mortality.

Conclusions: Among various pathogens, time to positivity > 24 h was associated with 30-day mortality for S. aureus.