Cefiderocol for the treatment of bloodstream infection due to MBL-producing Enterobacterales: a single-center retrospective cohort.

INTRODUCTION Bloodstream infections (BSIs) caused by metallo-β-lactamase (MBL)-producing Enterobacterales are associated with high mortality and limited therapeutic options. Real-world data on cefiderocol remain scarce.

Methods

We conducted a retrospective, single-centre study (January 2023-April 2025) including adult patients with MBL-producing Enterobacterales BSI who received cefiderocol for ≥72 hours. The main study outcome was 14-day clinical cure rate.

Results

Nineteen patients were included (mean age: 62.1 ± 12.1 years; median Charlson comorbidity index: 2.0 [IQR: 1.0 - 4.0]). Most (84.2%) had some form of immunosuppression. BSI sources were intra-abdominal (31.6%), respiratory (21.1%), and urinary tract (21.1%). Septic shock occurred in 10.5% of patients, and 26.3% required ICU admission. Median SOFA score at the initiation of cefiderocol was 5.0 days (4.5 - 8.5). Klebsiella spp. (89.5%) was the most common MBL-producing Enterobacterales (VIM [63.2%], NDM/OXA-48-like [26.3%], NDM [10.5%]). Prior colonization was observed in 36.8% of patients. Empirical therapy mainly included ceftazidime-avibactam plus aztreonam for a median duration of 2 days (IQR 0.5-3.5). Cefiderocol was administered for a median of 8.0 days [4.0-14.0], as monotherapy in 79% and as combination therapy in 10.5%. Clinical cure rate was achieved by day +14 in 78.9% (15/19) of patients. All-cause mortality by day +14 was 10.5% (2/19). Cefiderocol resistance emerged during therapy in three out of four patients not achieving clinical and microbiological cure (15.8% [3/19] of the cohort), and mainly involved NDM/OXA-48-like-coproducing K. pneumoniae.

Conclusions

Cefiderocol is a potential option for MBL-producing Enterobacterales BSIs, although its efficacy may be limited by the development of treatment-emergent resistance.