Use of a rapid detection test for extended-spectrum beta-lactamase from direct blood culture: an antimicrobial stewardship tool in a tertiary hospital in Spain.

Abstract

Introduction: Bacteremia caused by Gram-negative bacilli places a substantial burden on healthcare systems, mainly due to antibiotic resistance and delays in administering appropriate antimicrobial treatment (AT). The aim of this study was to describe the implementation of a rapid detection test (RDT) for CTX-M Extended Spectrum Beta-Lactamase-producing Enterobacterales (ESBL-PE) bacteremia as a tool for Antimicrobial Stewardship (AMS) in a tertiary hospital in Spain.

Material and methods: A cross-sectional study was conducted on blood culture (BC) samples from adult patients (≥18 years) admitted to a tertiary hospital in Spain (January 2021-February 2024). BCs with confirmed Enterobacterales identification were included. An RDT was used to detect CTX-M ESBL from direct BC. The results were reported to the AMS team. Data from electronic medical records and our laboratory information system were analyzed to explore the utility of implementing an RDT as an AMS tool.

Results: A total of 250 BCs from 250 patients were included. Empiric antimicrobial treatment (EAT) had not been prescribed in 41/250 (16.4%) patients, but was appropriately initiated in 33/250 (13.2%) after notification of the RDT results. Among those already receiving EAT (209/250, 83.6%), inappropriate and appropriate actions in AT were observed in 18/250 (7.2%) and 191/250 (76.4%) patients, respectively. By the time routine AST results were available, 241 (96.4%) patients had received appropriate treatment.

Conclusions: This study demonstrated the real-world application of an RDT to detect CTX-M ESBL directly from BC in a tertiary hospital. Early reporting of CTX-M ESBL status in Enterobacterales bacteremia enabled physicians and AMS teams to optimize AT.