How small modifications in laboratory workflow of blood cultures can have a significant impact on time to results

Abstract

Rapid identification and antimicrobial susceptibility testing of micro-organisms causing bloodstream infections is crucial in the management of septic patients. In this study, we compared a period of twice-daily and a period of thrice-daily reading of subculture agar plates. In 2016, 10,644 positive blood cultures bottles (bioMérieux) from 2608 patients were analyzed at UZ Leuven. Identification and antimicrobial susceptibility testing were performed by MALDI-TOF MS (Bruker Daltonics) and Vitek 2 (bioMérieux) respectively. In period 1 (January to June), subculture plates were read at 8:30 a.m. and 2:00 p.m. during the weekdays. In period 2 (August until December), reading was performed at 8:30 a.m., 2:00 p.m., and 5:00 p.m. Time to identification and time to AST results after positivity were compared. In period 1, median time to identification of all organisms was 22.8 h compared to 20.2 h in period 2 (p < 0.01). Moreover, micro-organisms were identified before 12 h in 9% of samples in period 2, a significant increase compared to 2% in period 1 (p < 0.01). In period 2, AST results were known within 36 h in 39% of samples, compared to 31% in period 1 (p < 0.01). Optimization of the reading frequency of subcultures of blood cultures significantly decreases time to results. Further optimization can be done by introducing lab automation. We will use the data of this study as a baseline to analyze the impact of introducing WASPLab (Copan Diagnostics) automation on time to results.

Laboratory Automation in Clinical Microbiology

“…The main benefit for the patient would be a clinically significant reduced time to report. Even in the classic systems this can be achieved by altering workflows and techniques [49,50,51]. However, the classic system will never reach the precision and timeliness of an automated system.…”

Collection, transport and storage procedures for blood culture specimens in adult patients: recommendations from a board of Italian experts

“…The transport time of inoculated BC bottles to the laboratory and their incubation in continuous monitoring systems is a critical factor, and any delay beyond the maximum limit can postpone or hamper microbial growth [64,65].…”

Performance and potential clinical impact of Alfred60AST (Alifax®) for direct antimicrobial susceptibility testing on positive blood culture bottles

“…Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection [1,2]. The early administration of appropriate antibiotics in patients with severe sepsis and septic shock improves mortality, reduces the length of hospital stay, and limits the development of resistance [1,3,4,5,6].…”

“…In UZ Leuven, a tertiary hospital with a positivity rate of around 900 positive BC bottles per month, the current median time to obtain AST result of the microorganism is approximately 40 h after positivity detection by the BacT/alert system (bioMérieux) [2]. In order to reduce the turnaround time, we evaluated the impact of introducing Alfred60 AST for direct susceptibility testing on positive BC bottles from a selected patient group.…”