Infection Control

Infection Control

Infection control is a cornerstone of safe nursing practice and a frequently tested topic on the NCLEX-RN. Nurses play a central role in preventing the transmission of infectious agents in healthcare settings. Understanding the chain of infection and the precautions that break each link is essential for clinical practice and exam success. For related terms, see the Safe Care Glossary.

The Chain of Infection

Infection transmission requires all six links of the chain to be intact. Breaking any single link prevents infection. Understanding each link helps nurses identify appropriate interventions.

1. Infectious Agent: The pathogen (bacterium, virus, fungus, parasite, prion) that causes disease. Interventions: proper use of antibiotics, disinfection, sterilization, and antimicrobial cleaning agents.
2. Reservoir: The place where the pathogen lives and multiplies (humans, animals, water, soil, medical equipment). Interventions: proper cleaning and maintenance of equipment, environmental sanitation, identifying and treating carriers.
3. Portal of Exit: The route by which the pathogen leaves the reservoir (respiratory tract, GI tract, blood, skin/mucous membranes, genitourinary tract). Interventions: covering coughs and sneezes, proper wound care, safe handling of body fluids.
4. Mode of Transmission: How the pathogen travels from the reservoir to the host. Modes include contact (direct and indirect), droplet, airborne, and vector-borne. Interventions: hand hygiene, PPE, isolation precautions, vector control.
5. Portal of Entry: How the pathogen enters the susceptible host (same routes as portal of exit, plus invasive devices such as IV lines, urinary catheters, and surgical wounds). Interventions: aseptic technique, catheter care, wound care, sterile procedures.
6. Susceptible Host: A person who is at risk for infection due to compromised defenses (immunosuppression, extremes of age, chronic illness, malnutrition, breaks in skin integrity). Interventions: immunization, nutrition support, protecting immunocompromised patients.

Standard Precautions

Standard precautions apply to all patients at all times, regardless of suspected or confirmed infection status. They are based on the principle that all blood, body fluids (except sweat), non-intact skin, and mucous membranes may contain transmissible infectious agents.

• Hand hygiene before and after every patient contact
• Use of PPE (gloves, gown, mask, eye protection) when exposure to blood or body fluids is anticipated
• Safe injection practices (one needle, one syringe, one time)
• Respiratory hygiene and cough etiquette
• Safe handling of contaminated equipment and linens
• Proper handling and disposal of sharps
• Environmental cleaning and disinfection

Transmission-Based Precautions

Transmission-based precautions are used in addition to standard precautions for patients with known or suspected infections that require extra measures.

Type	Mechanism	Room Requirements	PPE Required	Common Conditions
Airborne	Particles less than 5 microns that remain suspended in air	Negative-pressure airborne infection isolation room (AIIR) with door closed	N95 respirator (or PAPR); patient wears surgical mask during transport	Tuberculosis (TB), measles (rubeola), varicella (chickenpox), disseminated herpes zoster
Droplet	Particles greater than 5 microns that travel short distances (3-6 feet)	Private room preferred; spatial separation of at least 3 feet; door may remain open	Surgical mask within 3-6 feet of patient	Influenza, pertussis, diphtheria, mumps, meningococcal meningitis, rubella, respiratory viruses (RSV)
Contact	Direct or indirect contact with patient or contaminated surfaces	Private room preferred; dedicated equipment	Gloves and gown upon room entry	MRSA, VRE, C. difficile, scabies, herpes simplex, RSV (also droplet), norovirus

NCLEX Memory Aid: Think "MTV" for airborne precautions -- Measles, Tuberculosis, Varicella (chickenpox). Think "SPIDERMAN" for droplet -- Sepsis, Pertussis, Influenza, Diphtheria, Epiglottitis, Rubella, Meningitis, Adenovirus, Pneumonia (Mycoplasma).

Hand Hygiene

Hand hygiene is the single most effective measure to prevent healthcare-associated infections.

• Alcohol-based hand rub (ABHR): Preferred for routine decontamination when hands are not visibly soiled. Apply product to palm and rub all surfaces of hands until dry (at least 20 seconds).
• Soap and water: Required when hands are visibly soiled, after caring for patients with C. difficile or norovirus (alcohol does not kill spores), before eating, and after using the restroom. Wash for at least 20 seconds.
• When to perform hand hygiene: Before patient contact, before aseptic procedures, after body fluid exposure, after patient contact, and after contact with patient surroundings (the WHO "5 Moments").

PPE Donning and Doffing Order

The correct sequence for putting on and removing PPE is critical to prevent self-contamination.

• Donning order (putting on): (1) Hand hygiene, (2) Gown, (3) Mask or respirator, (4) Goggles or face shield, (5) Gloves (over gown cuffs)
• Doffing order (removing): (1) Gloves (most contaminated), (2) Goggles or face shield, (3) Gown, (4) Hand hygiene, (5) Mask or respirator (touching only the straps), (6) Hand hygiene again

Key principle: Gloves are always removed first during doffing because they are the most contaminated item. The mask or respirator is removed last because it protects the airway. Perform hand hygiene between removing the gown and the mask, and again after removing the mask.

Sterile Technique

Sterile (surgical) asepsis eliminates all microorganisms, including spores. Key principles include:

• A sterile field is created just before use and not left unattended.
• Only sterile items are placed on a sterile field.
• A sterile item that contacts a non-sterile item is considered contaminated.
• The outer 1-inch border of a sterile field is considered non-sterile.
• Sterile items held below waist level are considered contaminated.
• Moisture contamination: a wet sterile field is considered contaminated (strike-through contamination).
• When in doubt about sterility, consider the item contaminated.

Common NCLEX Infection Control Questions

• Room assignments: Patients with the same organism can be cohorted. Never place an immunocompromised patient with an infected patient. Airborne precaution patients require a private negative-pressure room.
• Visitor education: Teach visitors hand hygiene, proper PPE use, and when to avoid visiting (if they are ill).
• Priority nursing actions: If a question asks what the nurse should do first when a patient is placed on isolation, the answer is typically hand hygiene or donning appropriate PPE before entering the room.

For a printable reference, see the Infection Control Cheat Sheet. Continue reviewing with the Safe Care Study Guide or practice with Safe Care Flashcards.