Cefiderocol use in Gram negative infections with limited therapeutic options: Is combination therapy the key?

To date limited information about cefiderocol use is provided by real life studies. Our aim is to evaluate characteristics and outcome of patients with Gram-negative infections with limited therapeutic options treated with cefiderocol in combination or monotherapy.

We retrospectively collected data on demographical, clinical characteristics and clinical cure, in-hospital and 30-days mortality, microbiological failure and Clostridioides difficile infections of all patients ≥ 18 years old treated with cefiderocol for ≥ 48 h.

There were 18 patients of which 14 (77.8%) treated with cefiderocol in combination and 4 (22.2%) with monotherapy. Median age was 54.5 (IQR 35.25-65.75) vs 70.5 (IQR 57.5-78.25) years old, respectively and ward of admission was the ICU in the 78.57% vs 100% of cases. In the 50% vs 100% of cases infections were VAP with concomitant bloodstream infections. Median SOFA score was 10 (IQR 4.5-12.5) vs 5 (IQR 4-6) and APACHE II score was 13.5 (IQR 7.5-18) vs 16 (IQR 8.5-23.5), respectively. Isolated pathogen was carbapenems-resistant Acinetobacter baumannii in 78.57% vs 100% of cases. Median duration of cefiderocol treatment was 9.5 (IQR 7-13.25) vs 9 days (IQR 5.5-12.5) and in 77.8% patients it was used in combination therapy, of which 57.1% were colistin-spairing regimens. Clinical cure was achieved in 64.29% for combination therapy vs 75% of monotherapy treated patients, 30-days mortality rate was 28.57% vs 25% and 30-day ICU admission rate was 14.29% vs 50%, respectively. No statistically significant differences were observed between combination therapy and monotherapy treated patients.

To date, no differences have been demonstrated between cefiderocol monotherapy or combination. Further studies are required to understand whether cefiderocol combination therapy could provide an advantage in outcome in seriously-ill patients.