Implementation of a Bundle for the Management of Patients With Gram-Negative Bloodstream Infection: A Pre-Post Quasi-experimental Study

Background Lack of international guidelines for gram-negative bloodstream infection (GN-BSI) management poses clinical challenges. We aimed to assess whether implementing a management bundle for patients with GN-BSI affected mortality and/or emergence of multidrug resistance (MDR). Methods This was a single-center, quasi-experimental study including adult patients hospitalized with monomicrobial GN-BSI. In the preimplementation phase ("pre-phase,"2018-2019), no standardized protocol was used. In the postimplementation phase ("post-phase,"2022-2023), a bundle was applied including predefined rules for follow-up blood cultures (FU-BCs), imaging, β-lactam administration schedule, and treatment duration. Primary endpoint was 30-day all-cause mortality; secondary endpoint was 30-day MDR-GN carriage or infection. Treatment-effect lasso models were used to estimate bundle impact. Results A total of 2683 patients were included: 1430 in the pre-phase and 1253 in the post-phase. FU-BCs were performed in 22.5% (n = 322) versus 47% (n = 589), P <. 001, and imaging in 65.5% (n = 936) versus 71.6% (n = 897), P <. 001; median treatment duration was 10 days in both phases (P =. 625). Thirty-day mortality was 10.7% (n = 153) versus 11.6% (n = 143), P =. 467. New MDR carriage/infection was 140 (11.0%) versus 78 (6.5%), P <. 001. The bundle had no overall effect on 30-day mortality (average treatment effect [ATE] = 0.008, P =. 568), despite reduced mortality in BSIs due to carbapenem-resistant organisms (ATE = -0.074, P =. 197); the effect was not significant. MDR emergence was significantly reduced (ATE = -0.038, P =. 031) in both overall and high-risk populations. Conclusions The GN-BSI management bundle reduced MDR.