Cumulative cefepime exposure in cancer patients is associated with an increased risk of ertapenem non-susceptible, meropenem susceptible Enterobacterales bacteremia

Non-carbapenemase-producing (non-CP) carbapenem-resistant Enterobacterales (CRE) are an important classification of CRE. Increasing rates of non-CP CRE that display carbapenem susceptibility discordance (CSD-E; ertapenem-resistant, meropenem susceptible) have been observed globally and at our institution. Our article aims to characterize risk factors, including cumulative antibiotic exposure, leading to carbapenem susceptibility discordant Enterobacterales (CSD-E) bloodstream infection (BSI) in immunocompromised patients with a history of Enterobacterales BSI. In addition, we analyzed paired whole-genome sequencing data to assess antimicrobial gene content for mechanistic rationales supporting our clinical findings. The risk factors for CSD-E development identified in this study require further validation in multicenter cohorts.