Evolution of carbapenem-resistant Klebsiella pneumoniae after ceftolozane-tazobactam exposure in a patient after cord blood transplantation

A patient undergoing cord blood transplantation developed fatal carbapenem-resistant Klebsiella pneumoniae (CRKP) bacteremia, with rapid emergence of multidrug resistance during treatment. Whole-genome sequencing revealed multiple beta-lactamase genes and an ompK36 mutation, highlighting the need for careful antimicrobial stewardship in immunocompromised patients.