Inclusion criteria:

- Individuals who present with the onset of febrile neutropenia and at the same time present colonization with an ESBL-producing pathogen (identified through positive routine rectal swabs and/or positive culture of clinical specimen) or risk of infection with an ESBL-producing pathogen (use of 3rd/4th gen cephalosporin or piperacillin/tazobactam for at least 48 hours in the last 30 days).

Exclusion Criteria:

• Patients known to be colonized with carbapenem-resistant or CEF/TAZ-resistant pathogens
• Patients with previous use of carbapenems for at least 48h in the past 30 days are also excluded due to risk of resistance to the study drugs.
• Growth of a pathogen resistant to either study drug in a relevant clinical specimen during the intervention phase will be followed by adjustment of therapy according to local protocol, unblinding, and exclusion from the study.
• Patients that have received less than 72h of either study drug will also be excluded from the final analyses.