Background and Importance Cefiderocol is a novel siderophore-cephalosporin conjugate, with activity against carbapenem-resistant and multidrug-resistant gram-negative bacilli. The novelty of and need for cefiderocol are clear but available real-setting clinical data are limited.

Aim and Objectives To determine the effectiveness of cefiderocol (microbiological eradication, clinical cure, and recurrence), and mortality of treated infections.

Material and Methods Retrospective study that included all patients with active infection and treatment with cefiderocol during March 2021 to July 2023. Demographic, clinical, infection, and treatment variables were collected. Patients with microbiological eradication (negative culture), clinical cure, recurrence of infection (positive culture), early (7–10 days from initiation of cefiderocol), and 30-day mortality were calculated. Statistical analysis: values were expressed as medians (interquartile range) and patients (percentages).

Results Forty-three patients initiated treatment with cefiderocol, 27/43 (62.8%) were male with a median age of 66.0 (57.7–73.5) years. The median hospital stay was 64.1 (29.9–89.3) days, 29/43 (67.4%) patients required intensive care unit (ICU) admission, with a median stay of 42.0 (25.0–83.0) days. The main focus of infection was respiratory (16/43, 37.2%), followed by urinary (10/43, 23.3%), intra-abdominal (5/43, 11.6%), skin and soft tissue (5/43, 11.6%), endovascular (4/43, 9.3%) and osteoarticular (3/43, 7.0%). 5/43 (11.6%) patients presented another focus and 11/43 (25.6%) had sepsis. A total of 57 multidrug-resistant gram-negative and 14 gram-positive bacteria were isolated. In 19/43 (44.2%) patients more than one microorganism were isolated. Resistance to cefiderocol was recorded in 3/43 (7.0%) patients. The median treatment was 9.0 (6.0–17.5) days. In 36/43 (83.7%) patients more than one antibiotic was used, and 18/43 (41.9%) of them, with synergistic action.

In 31/43 (72.2%) patients microbiological eradication was achieved, in 4/43 (9.3%) it was indeterminate, and in 35/43 (81.4%) patients achieved a clinical cure. Mortality rates: early 2/43 (4.7%), at 30 days 7/43 (16.3%) and intra-hospital 13/43 (30.2%). The recurrence rate was 8/43 (18.6%).

Conclusion and Relevance Cefiderocol was effective in the treatment of multidrug-resistant gram-negative bacteria infections in our cohort, with a high rate of admission to the ICU, and large hospital stay. Microbiological eradication was lower than clinical cure, influenced by loss of values. Mortality rates were low in this clinical stage, with intra-hospital mortality being the highest.

Conflict of Interest No conflict of interest.