Ceftolozane-tazobactam Versus Meropenem for ESBL and AmpC-producing Enterobacterales Bloodstream Infection

Inclusion Criteria: * Bloodstream infection defined as presence in at least one peripheral blood culture draw demonstrating Enterobacterales with proven non-susceptibility to third generation cephalosporins or cephalosporin susceptible species known to harbour chromosomal AmpC-beta-lactamases (Enterobacter spp., Klebsiella aerogenes, Citrobacter freundii, Morganella morganii, Providencia spp. or Serratia marcescens) during hospitalisation * Patient is aged 18 years and over (21 and over in Singapore) * The patient or approved proxy is able to provide informed consent * ≤72 hours has elapsed since the first positive qualifying (index) blood culture collection * Expected to receive IV therapy for ≥5 days Exclusion Criteria: * Known hypersensitivity to a cephalosporin or a carbapenem, or anaphylaxis to beta-lactam antibiotics * Participant with significant polymicrobial bloodstream infection (i.e. not a contaminant) * Treatment is not with the intent to cure the infection (i.e. palliative intent) or the expected survival is ≤4 days * Participant is pregnant or breast-feeding (tested for in women of child-bearing age only) * Use of concomitant antimicrobials with known activity against Gram-negative bacilli (except trimethoprim/sulfamethoxazole for Pneumocystis prophylaxis and when adding metronidazole for suspected IAI) in the first 5 days post-randomisation * Participant with CrCl \<15 mL/minute or on renal replacement therapy (in addition, participants will be withdrawn fro…