NCLEX Review Guide: Infectious Diseases - General Concepts & Standard Precautions

Six Components of Infection Transmission

• Infectious agent: Pathogenic microorganisms including bacteria, viruses, fungi, and parasites that cause disease in susceptible hosts.
• Reservoir: The environment where pathogens live and multiply, including humans, animals, equipment, and environmental surfaces.
• Portal of exit: The pathway by which pathogens leave the reservoir, such as respiratory secretions, blood, urine, feces, or open wounds.
• Mode of transmission: How pathogens travel from reservoir to host through direct contact, indirect contact, droplet, or airborne routes.
• Portal of entry: The pathway pathogens use to enter a new host, including mucous membranes, broken skin, respiratory tract, or invasive devices.
• Susceptible host: An individual whose immune system cannot resist pathogenic invasion due to compromised immunity, chronic illness, or invasive procedures.

Universal Application Principles

• Standard precautions are infection control practices applied to all patients regardless of diagnosis, treating all body fluids as potentially infectious.
• Hand hygiene must be performed before and after every patient contact, after removing gloves, and when hands are visibly soiled using alcohol-based sanitizer or soap and water.
• Personal protective equipment (PPE) selection depends on anticipated exposure: gloves for body fluid contact, gowns for clothing protection, masks/eye protection for splash risk.
• Safe injection practices require using sterile, single-use disposable needles and syringes for each injection, never reusing or sharing between patients.

Proper Hand Hygiene Technique

1. Apply alcohol-based sanitizer to palm of one hand
2. Rub hands together, covering all surfaces
3. Continue rubbing until hands are dry (15-20 seconds)
4. For soap and water: wet hands, apply soap, scrub 15-20 seconds, rinse, dry with clean towel

Contact, Droplet, and Airborne Precautions

• Contact precautions prevent transmission through direct patient contact or contaminated environmental surfaces, requiring gloves and gowns for all patient interactions.
• Droplet precautions prevent transmission of large respiratory droplets (>5 micrometers) that travel short distances, requiring surgical masks within 3 feet of patient.
• Airborne precautions prevent transmission of small particles (<5 micrometers) that remain suspended in air, requiring N95 respirators and negative pressure isolation rooms.

Knowledge Check

• ☐ I can identify all six components of the chain of infection
• ☐ I understand when to apply standard precautions (always!)
• ☐ I can differentiate between contact, droplet, and airborne precautions
• ☐ I know proper hand hygiene technique and timing
• ☐ I can select appropriate PPE based on transmission route
• ☐ I understand proper PPE donning and doffing sequence