This document discusses antibiotic usage guidelines in the ICU. It outlines principles for prescribing antibiotics such as sending appropriate cultures and following hospital antibiotic policies. It also describes strategies to optimize antibiotic use like patient risk stratification, de-escalation therapy, and implementing an antibiotic stewardship program. Common ICU infections like ventilator-associated pneumonia, urosepsis, and catheter-related bloodstream infections are reviewed along with treatment approaches and preventive measures.