Lab efficiency and improvements in the management of bloodstream infections: a before and after study

Abstract

Purpose: Early availability of identification of bacterial pathogens and knowledge of their antimicrobial susceptibility is crucial when managing patients with bloodstream infections (BSI). We aimed to assess the impact of the laboratory conversion (full automation and conversion to 24/7 workflow) on laboratory efficiency, timeliness of diagnostic results, and patient outcomes.

Methods: An observational retrospective study was conducted to compare lab organisation, laboratory times including turnaround time (TAT) for positive blood cultures (PBCs), antimicrobial therapy (antibiotic prescription, time to first antibiotic modification), patient outcomes (30-day mortality, hospital and ICU discharge), and antibiotic consumption for pre- and post-conversion periods (January to December 2019 versus June 2021 to May 2022) in adults with BSI admitted to the ICU at the Centre Hospitalier de Valenciennes. Multivariable models were used to compare periods, adjusting for relevant patient characteristics.

Results: A total of 116 and 128 PBCs from 104 to 112 patients in pre- and post-conversion were analysed. TAT decreased significantly for clinically significant episodes (median 30.4 (n = 83) versus 27.1 h (n = 84), p = 0.004). The percent of PBCs with antimicrobial susceptibility testing results available within 24 h increased significantly for night shift PBCs (0.9% versus 18.7%; p < 0.0001). A significant reduction in time to first antibiotic modification occurred (median difference of 19.1 h, p = 0.04). Additionally, we observed for the post-conversion a 51% increase in probability of ICU discharge (hazard ratio [HR] = 1.51, 95%CI 1.09‒2.08, p = 0.014) and a trend towards a reduction in 30-day mortality (HR = 0.65, 95%CI 0.40‒1.06, p = 0.085).

Conclusion: Laboratory reorganisation improved laboratory efficiency, leading to improvements in the management of patients with BSIs.

Clinical Trial Number: Not applicable.

Supplementary Information: The online version contains supplementary material available at 10.1007/s10096-025-05200-x.

Keywords: Antimicrobial stewardship; Bloodstream infections; Efficiency; Lab automation.

Fig. 1

Laboratory efficiency indicators pre- and post-conversion. A. Median times for positivity, Gram staining, ID and AST for clinically significant episodes. B. Percent of positive blood cultures with AST results available within 24 h. AST, antimicrobial susceptibility testing; ID, identification; PBC, positive blood culture

Fig. 2

Clinical outcomes in pre (red)/post (blue) conversion periods. A. Kaplan-Meier survival curve within 30 days after loading the PBC into the system in days. B. Cumulative probability of hospital discharge from hospital admission with death as competitive risk (dotted line). C. Cumulative probability of ICU discharge from ICU admission with death as competitive risk (dotted line)