The Prognostic Value of Time to Positivity of Klebsiella Pneumoniae in Blood Cultures of Elderly Patients With Intra-Abdominal Infection.

Background: Elderly patients with intra-abdominal infection are more vulnerable to sepsis progression, especially in those who had concomitant bacteremia. The time to positivity (TTP) of blood cultures in patients with bacteremia is considered to be a prognostic factor for some bacterial species. This study aimed to investigate the prognostic value of TTP in elderly patients with intra-abdominal infection and Klebsiella pneumoniae bacteremia.

Methods: A retrospective observational, case-control study was conducted at a single tertiary referral medical center. All elderly (aged ≥ 65 years) patients diagnosed with intra-abdominal infection and Klebsiella pneumoniae bacteremia in the emergency department between July 1, 2016, and June 30, 2021 were enrolled. The baseline characteristics, TTP of blood cultures, management strategy, and outcomes of each eligible patient were recorded and analyzed. The primary outcome was to examine the association between TTP and the 30-day mortality risk in enrolled patients.

Results: A total of 101 patients were included in the study. The overall 30-day mortality rate was 11.9% (12/101). The median TTP of Klebsiella pneumoniae in the eligible patients was 12.5 (11-16) hours. There was a stepwise significantly decreased mortality rate as TTP increased (p = 0.04). The TTP had a moderate mortality discrimination ability (area under receiver operating characteristic curve = 0.75, 95% CI = 0.65-0.83, p < 0.01). Furthermore, the Pittsburg bacteremia score (hazard ratio [HR] = 2.19, p < 0.01) and TTP (HR = 0.82, p = 0.04) were identified as independent factors associated with 30-day mortality.

Conclusions: TTP was associated with 30-day mortality risk in elderly patients with Klebsiella pneumoniae bacteremia and intra-abdominal infection. Clinicians can utilize TTP for risk stratification, and initiate prompt treatment in those patients with shorter TTP.