[Cefiderocol in AML patient with neutropenic infection due to 4MRGN Klebsiella pneumoniae (VIM-1)].

ANAMNESIS: The 68-year-old patient presented with fever, general malaise and physical weakness in neutropenia during a known relapse of acute myeloid leukaemia after allogeneic stem cell transplantation.

TREATMENT/DIAGNOSIS: Due to immune suppression, an empiric antibiotic therapy with piperacillin/tazobactam was started. The 4MRGN screening was positive. For this reason, therapy was switched empirically to ceftazidime/avibactam plus colistin. A tongue ulcer with abscess formation and phlegmonous soft tissue reaction was revealed as the focus of the infection. Several microbiological probes including a blood culture discovered Klebsiella pneumoniae complex - 4MRGN that expressed a metallo-beta-lactamase of the VIM-1 type (Verona integron metallo betalactamase-1). A permanent improvement of the clinical symptoms and regredience of the infection parameters could only be achieved after antibiotic treatment was switched to the recently approved siderophor cephalosporin cefiderocol. After 18 days the antibiotic treatment could be completed successfully. The patient was discharged in a stable condition.

CONCLUSION: 4MRGN pathogens are Gram-negative rod-shaped bacteria that are resistant against four main bactericidal antibiotic groups (Acylureidopenicillins, 3rd generation cephalosporins, carbapenems, and fluoroquinolones) and thus difficult to treat. The present case demonstrates good clinical efficacy for cefiderocol even in pathogens resistant to antibiotics such as colistin and ceftazidime/avibactam and highlights the importance of antibiogram-tailored therapy.