This document discusses bloodstream infections (bacteremia and sepsis). It defines the different types of bloodstream infections including bacteremia, sepsis, severe sepsis, and septic shock. It describes the typical clinical features and pathophysiology of sepsis. It also outlines the various causes and sources of bacteremias including those related to specific infections, medical devices, intravenous drug use, and hospital-acquired infections. Finally, it discusses the diagnostic approach using blood cultures and treatment approach typically involving antibiotics, organ support, and source control.