A diagnostic stewardship bundle approach to facilitate same-day optimal antimicrobial therapy in gram-negative sepsis: a quasi-experimental study

It is challenging to reduce time to optimal antimicrobial therapy in patients with sepsis for microbiology laboratories in low to middle-income countries. We evaluated the diagnostic accuracy and impact of a diagnostic stewardship bundle titled "Sepsis-24" to reduce turnaround time (TAT) of provisional blood culture reports (pBCR) ≤ 24 h in patients with gram-negative bacteraemia. During the preintervention period (January-May 23), the key preanalytical and analytical parameters of automated blood culture diagnostics were optimized in a multiphasic manner. Early microbial identification and susceptibility testing were performed by direct inoculation of VITEK-2 identification cards from flagged blood culture bottles (+ BCs) and EUCAST RAST method, read at 8-hour. During the intervention period (June-December 2023), Sepsis-24 was implemented in adult ICUs to provide pBCR for four RAST reportable gram-negatives (RRGNs). The agreements of direct microbial identification and RAST for tested drug-bug combinations were 94% [95%CI: 90-98] and 93% [95%CI: 91-94], respectively during both periods. There was a statistically significant reduction in BC loading, unloading and performance of direct VITEK/RAST from + BC during intervention period [median (minutes): 32 versus 25, 12 versus 2, and 181 versus 70, p ≤ 0.001, respectively]. Of 49 pBCRs released, 48 (98%) were concordant in species-level microbial identification with a median TAT of 1473 min [IQR: 1635 - 1321], from sample receiving. Sepsis-24 facilitated early review of antimicrobial regimen in 71% (34/48) patients leading to therapy change in 64.7% (22/34) patients. Sepsis-24 was found to be diagnostically accurate and facilitated early review of antimicrobial therapy in our resource-limited setting.