Infection control is based on breaking the chain of infection: infectious agent, reservoir, portal of exit, mode of transmission, portal of entry, and susceptible host. Standard precautions apply to ALL patients regardless of diagnosis and include hand hygiene, PPE use when contact with blood/body fluids is anticipated, and safe injection practices. Transmission-based precautions add pathogen-specific barriers: Contact precautions (gown + gloves) prevent spread via direct/indirect contact, Droplet precautions (surgical mask within 3 feet) prevent spread of large respiratory droplets (>5 microns) that travel <6 feet, and Airborne precautions (N95 respirator + negative pressure room) prevent spread of airborne nuclei (<5 microns) that remain suspended and travel >6 feet through air currents. Enhanced barrier precautions (EBP) for multidrug-resistant organisms add gown and gloves for high-contact resident care activities in long-term care settings.