Clinical, microbiological characteristics and predictors of mortality in patients with carbapenemase-producing Enterobacterales bloodstream infections: a multicentre study

Summary: Objectives: To investigate the clinical, microbiological characteristics and outcomes of patients with bloodstream infections (BSI) due to carbapenemase-producing Enterobacterales (CPE). Methods: A multicentre retrospective observational study of patients with BSIs due to CPE admitted to six UK hospitals was conducted between 2011 and 2021. Multivariate analysis was used to identify factors predicting 30-day case fatality rate (CFR). Results: There were 84 episodes of CPE-BSIs, 37 (44%) due to OXA-48, 35 (42%) to metallo-betalactamases (MBL) and 12 (14%) to KPC. 63% of patients were male with a median age of 64 years. Common organisms included Klebsiella spp. (61%), Escherichia coli (20%) and Enterobacter spp. (13%). Urinary devices were more often involved in OXA-48 BSIs (12/37; 32%) compared to infections caused by MBL and KPC (4/35; 11% and 1/12; 8%; P = 0.046). In contrast, central venous catheters were more frequently present in KPC-BSIs (10/12; 92%) compared with OXA-48 and MBL (11/37; 30% and 20/35; 57%; P = 0.002). Effective definitive antimicrobials were received by 72/84 (86%) patients, comprising monotherapy (32/72; 44%) or combination therapy (40/72; 56%). 30-day case fatality rate (CFR) was 38%. Sepsis or septic shock was associated with death [OR 3.81 (CI 1.19–12.14), P = 0.024]. Conclusion: Strategies targeting high-risk patients and adherence to infection prevention bundles for urinary devices and central venous catheters can reduce OXA-48 and KPC-BSIs. Early recognition and management of severe sepsis, prompt initiation of appropriate antimicrobial therapy and development of novel antimicrobials are crucial to mitigate the high CFR associated with CPE-BSIs.