Hypothesis The BLING III Study will test the hypothesis that patients managed in the ICU with sepsis, the administration of beta-lactam antibiotics via continuous infusion decreases Day 90 mortality compared with intermittent infusion Design This BLING III study is a prospective, multicentre, open, phase III, RCT. Participants commenced on one of two beta-lactam antibiotics (piperacillin-tazobactam or meropenem) will be randomised to receive the beta-lactam antibiotic via either continuous infusion or intermittent infusion over 30 minutes for the treatment course while in the ICU for up to 90 days after randomisation. For participants where the beta-lactam antibiotic is subsequently changed from piperacillin-tazobactam to meropenem or vice versa for ongoing treatment of the infectious episode, the new prescription will continue to be administered in the allocated method (continuous infusion or intermittent infusion over 30 minutes).