Infection Prevention Basics

Healthcare-associated infections (HAIs) include catheter-associated urinary tract infections (CAUTIs), central line-associated bloodstream infections (CLABSIs), surgical site infections (SSIs), ventilator-associated pneumonia (VAP), and Clostridioides difficile infections. These are among the most common serious adverse events in healthcare — and nurses are the primary line of defense against their occurrence.

The chain of infection describes the six links required for infectious disease transmission: infectious agent → reservoir → portal of exit → mode of transmission → portal of entry → susceptible host. Infection prevention breaks any link in this chain — particularly hand hygiene, barriers (PPE), and environmental controls.

• Standard precautions: Applied to ALL patients regardless of diagnosis — treat all blood, body fluids, secretions, and non-intact skin as potentially infectious
• Transmission-based precautions: Added to standard precautions for known or suspected specific pathogens
• Hand hygiene: The single most effective infection prevention measure
• PPE: Gloves, gown, mask, eye protection — matched to the exposure risk and precaution type

Standard precautions are applied universally — with every patient, every time, regardless of diagnosis. They assume that all patients may carry transmissible pathogens and protect both patients and healthcare workers.

Standard precautions include:

• Hand hygiene: Before and after every patient contact, before aseptic tasks, after exposure to body fluids, after removing gloves
• Gloves: When touching blood, body fluids, secretions, excretions, mucous membranes, or non-intact skin; change between tasks and patients; hand hygiene after removal
• Gown: When contact with patient's environment or body fluids is anticipated
• Mask and eye protection: During procedures likely to generate splashes or sprays of blood, body fluids, or secretions
• Safe injection practices: One needle, one syringe, one patient — never reuse; use single-dose vials when possible
• Respiratory hygiene / cough etiquette: Instruct patients and visitors to cover coughs, use tissues, perform hand hygiene
• Safe handling of sharps: Never recap needles two-handed; use safety-engineered devices; dispose immediately in sharps containers
• Environmental controls: Routine cleaning and disinfection of patient care equipment and environment

Contact Precautions

Used for pathogens spread by direct contact (touching the patient or patient environment). Contact precautions are added on top of standard precautions.

• PPE: Gloves and gown — don upon entering the room, remove and perform hand hygiene before leaving
• Room: Private room preferred; dedicated patient care equipment (stethoscope, BP cuff)
• Examples: MRSA, VRE, C. difficile, scabies, RSV, herpes simplex (wounds)
• C. diff note: Use soap and water for hand hygiene (not alcohol-based sanitizer) — alcohol does not kill C. diff spores

Droplet Precautions

Used for pathogens transmitted via respiratory droplets (large droplets that travel <3–6 feet, do not remain airborne). Added on top of standard precautions.

• PPE: Surgical mask (not N95) — worn upon entering the room or within 3–6 feet of the patient
• Room: Private room preferred; keep door closed; patient wears surgical mask during transport
• Examples: Influenza, pertussis, meningococcal meningitis, mumps, rubella, streptococcal pharyngitis, COVID-19 (some protocols)

Airborne Precautions

Used for pathogens transmitted via airborne particles (small droplet nuclei that remain suspended in air and travel >3–6 feet, can circulate in ventilation systems). Most restrictive transmission-based precautions.

• PPE: N95 respirator (fitted) or PAPR — must be donned before entering the room
• Room: Negative-pressure airborne infection isolation room (AIIR) — 12 air exchanges per hour, door kept closed at all times
• Examples: Tuberculosis (TB), measles (rubeola), varicella (chickenpox), disseminated herpes zoster
• Patient transport: Patient wears surgical mask during transport (N95 is not placed on the patient)

Hand hygiene is the single most important action for preventing infection transmission in healthcare. Two methods are used: alcohol-based hand rub (ABHR) and soap and water. Each has specific indications.

WHO 5 Moments: before patient contact · before aseptic task · after body fluid exposure · after patient contact · after contact with patient surroundings

Correct donning (putting on) and doffing (removing) PPE is critical — improper doffing is a major route of self-contamination. The hands are the most contaminated surface during doffing.

• CAUTI prevention: Only insert urinary catheters when absolutely indicated; maintain closed sterile drainage system; remove as soon as clinically possible; perform routine perineal care
• CLABSI prevention: Use maximal barrier precautions during insertion; maintain dry sterile dressings; scrub the hub before every access; remove central lines when no longer needed
• VAP prevention: HOB elevation 30–45 degrees; oral care with chlorhexidine every 2–4 hours; spontaneous awakening and breathing trials; subglottic suctioning
• SSI prevention: Pre-operative skin preparation; appropriate prophylactic antibiotic timing; normothermia maintenance; aseptic wound care
• Environmental controls: Consistent terminal cleaning of patient rooms; dedicated equipment for isolation patients; environmental surveillance
• Patient and family education: Teach hand hygiene to patients and families — visitor hand hygiene is equally important for prevention