Successful eravacycline monotherapy for cefiderocol-resistant Acinetobacter baumannii bloodstream infection in a critically ill patient with concomitant Clostridioides difficile colitis

: Carbapenem-resistant Acinetobacter baumannii (CRAB) bloodstream infections (BSIs) are associated with high mortality and limited therapeutic options, particularly when resistance to novel agents such as cefiderocol emerges. We report the case of an 87-year-old critically ill woman with multiple comorbidities who developed cefiderocol-resistant CRAB BSI during hospitalization, concomitant with Clostridioides difficile colitis. The patient had previously received broad-spectrum antimicrobial therapy and ventilatory support. Cefiderocol resistance was detected by gradient diffusion (MIC Test Strip) on iron-depleted Mueller-Hinton agar, showing an MIC of 12 mg/L. Considering the resistance profile and concurrent C. difficile infection, antimicrobial therapy was switched to eravacycline monotherapy (1 mg/kg every 12 hours). Eravacycline susceptibility testing by gradient diffusion (ETEST) demonstrated an MIC of 0.75 mg/L. Treatment was administered for 14 days, resulting in clinical improvement and blood culture sterilization within 96 hours.