Monitoring Immune Dysfunction in Critically Ill Patients with Carbapenem-Resistant Acinetobacter baumannii Sepsis Treated with Regimens Including Cefiderocol: A Pilot Study to Identify Accessible Biomarkers to Stratify Patients' Prognosis

Multidrug-resistant (CRAB) infections are a serious problem in critical care. This study aims to develop an early prognostic score for immune paralysis, using practical and cost-effective parameters, to predict ICU mortality in patients with CRAB infections being treated with Cefiderocol. We carried out an observational pilot study on consecutive patients hospitalized in the ICU with ensuing septic infections treated with Cefiderocol monotherapy or Cefiderocol including combinations. We investigated the predictive power of lymphocyte counts, lymphocyte subpopulations, serum cholinesterase levels, and reactivation of herpes viruses. Overall, 36 of 39 patients entered in our analysis: 20 survivors and 16 deceased. A total of 12 patients developed bacteremia, 19 patients had HAP/VAP, and 5 patients had a soft tissue infection. Univariate analyses of factors associated with unfavorable outcome revealed a significant association for age (OR: 1.5, CI: 1.11-2.02), SAPS II (OR: 1.05, CI: 1.01-1.1), SOFA score (OR: 1.37, CI: 1.06-1.76), lymphocytopenia (OR: 32.5, CI: 3.45-306.4), viral reactivation (OR: 9.75, CI: 1.72-55.4), and cholinesterase drop