Blood culture plays a crucial role in identifying the causative microorganisms in patients with bacteremia, aiding in the selection of appropriate antibiotics and treatment strategies. Bacteremia can easily progress to severe conditions, and Staphylococcus aureus bacteremia particularly has a high mortality rate, ranging from 15 % to 40 % [1,2].

Another factor contributing to mortality in Staphylococcus aureus bacteremia is methicillin-resistant Staphylococcus aureus (MRSA), which has a higher mortality rate than methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia [3].

Several studies have compared the time to blood culture positivity and mortality risk; however, the results have been inconsistent. Some studies have shown that a time to positivity (TTP) within 24 h is associated with higher mortality [4], while others have reported that a TTP exceeding 24 h is associated with higher mortality [5,6]. In contrast, another study reported that a higher proportion of patients with a TTP within 24 h had central venous catheter-related bloodstream infections or infective endocarditis, suggesting that bacterial load may contribute to mortality risk and TTP [7,8]. A previous study analyzed the mortality rates using the number of positive blood culture sets, which may correlate with the bacterial load [9]. The results showed that the mortality rate was higher in patients with only one positive set than in those with two or more positive sets. When blood cultures become positive after more than 24 h, this suggests a lower bacterial load at the start of treatment.

Based on these studies, a longer TTP and fewer positive sets were associated with higher mortality, suggesting delayed administration of antibiotics or a lower bacterial load. However, these studies lacked sufficient information regarding the timing of effective antibiotic administration after the initiation of treatment and should be included in future analyses. Furthermore, there has been no direct comparison between TTP and the number of positive bottles; therefore, these associations remain speculative. This study aimed to investigate the correlation between TTP and the number of positive sets. Additionally, we aimed to examine whether an association exists between TTP, the number of positive bottles, and mortality or the presence of disseminated lesions.