Inclusion Criteria:  ≥18 years of age Comatose (do not follow simple verbal commands) Have any initial heart rhythm (shockable or non-shockable) OHCA including the emergency department  Exclusion Criteria:  Name on opt-out list In-hospital cardiac arrest Interval >6 hours from ICU admission to study drug receipt Preexisting terminal disease making 180-day survival unlikely Refused informed consent Emergent coronary artery bypass grafting Anaphylaxis or angioedema to beta-lactam antibiotics (i.e., cephalosporins or penicillins) Under legal guardianship or prisoner Known colonization with methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant enterococcus (VRE)  Clinical bacterial infection prior to hospital admission defined as any one of the following:  Infectious prodrome preceding OHCA Active course of antibiotics for infection prior to admission Active infection documented in the electronic medical record Family or surrogate endorsement of an active infection