BNS Section 3: Infection Control

Section Overview

Infection control is among the most consequential competencies a nurse develops. Healthcare-associated infections (HAIs) affect approximately 1 in 31 hospitalized patients on any given day in the United States, contributing to preventable morbidity, mortality, prolonged hospital stays, and significant healthcare costs. The nurse’s consistent application of evidence-based precautions — hand hygiene, PPE, sterile technique, and isolation — directly prevents transmission and protects patients, families, and the care team.

This section covers the chain of infection, standard and transmission-based precautions, hand hygiene, PPE use, and the principles of medical and surgical asepsis. These foundational skills underpin every subsequent module in the Basic Nursing Skills course, including hygiene care, urinary catheterization, wound care, and IV medication administration.

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Learning Objectives

By the end of this section, students will be able to:

1. Explain the six links of the chain of infection and identify nursing strategies to break each link. (Bloom’s: Understand)
2. Demonstrate correct hand hygiene technique using soap and water and alcohol-based hand rub per current CDC and WHO guidelines. (Bloom’s: Apply)
3. Apply standard precautions consistently with all patients regardless of known infection status. (Bloom’s: Apply)
4. Select appropriate transmission-based precautions — contact, droplet, or airborne — based on the pathogen and clinical situation. (Bloom’s: Analyze)
5. Perform correct donning and doffing of personal protective equipment in the proper sequence to prevent self-contamination. (Bloom’s: Apply)
6. Distinguish between medical asepsis and surgical asepsis and apply each in the appropriate clinical context. (Bloom’s: Analyze)
7. Implement isolation procedures that protect patients, staff, and visitors while preserving patient dignity. (Bloom’s: Apply)

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The Chain of Infection

Disease transmission requires that six interconnected links remain intact. Breaking any single link stops the spread of infection. Nursing interventions target multiple links simultaneously.

Link	Definition	Nursing Intervention to Break It
1. Infectious Agent	The pathogen (bacterium, virus, fungus, parasite) capable of causing disease	Appropriate antibiotic/antiviral therapy; proper medication administration
2. Reservoir	The environment in which the pathogen lives and multiplies (human host, soil, water, equipment)	Environmental cleaning; treating infected patients; proper sharps disposal
3. Portal of Exit	The route by which the pathogen leaves the reservoir (respiratory secretions, blood, feces, wound drainage)	Respiratory hygiene/cough etiquette; containment of body fluids
4. Mode of Transmission	The mechanism by which the pathogen travels (contact, droplet, airborne, vehicle, vector)	Hand hygiene; PPE; isolation; sterilization of equipment
5. Portal of Entry	The route by which the pathogen enters a new host (mucous membranes, non-intact skin, GI/respiratory tract)	Intact skin care; sterile technique for invasive procedures
6. Susceptible Host	A person who lacks adequate immunity to resist the pathogen	Vaccination; optimizing nutrition and hydration; reducing immunosuppressive risk factors

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Hand Hygiene

Hand hygiene is the single most important measure for preventing HAIs. The CDC and WHO identify five moments at which hand hygiene is mandatory:

1. Before touching a patient
2. Before a clean or aseptic procedure
3. After exposure risk to body fluids
4. After touching a patient
5. After touching the patient’s surroundings

Alcohol-Based Hand Rub (ABHR)

ABHR is preferred for routine hand hygiene when hands are not visibly soiled. Apply 1–3 mL (one full pump) to the palm, rub all surfaces including between fingers, backs of hands, thumbs, and fingertips, until the product is completely dry (approximately 20–30 seconds).

When ABHR is NOT sufficient:

• Visible soil or organic matter on hands → use soap and water
• After caring for a patient with Clostridioides difficile infection → use soap and water (spores are not inactivated by ABHR)
• Before eating or after using the restroom → use soap and water

Soap and Water Technique

1. Wet hands with warm water
2. Apply soap and lather all surfaces for a minimum of 20 seconds (singing “Happy Birthday” twice approximates the correct duration)
3. Rinse under running water, fingers pointing downward
4. Dry thoroughly with a single-use paper towel
5. Use the paper towel to turn off the faucet

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Standard Precautions

Standard precautions are applied with every patient during every care encounter, regardless of known infection status or diagnosis. They represent the baseline minimum for infection prevention in healthcare.

Standard precautions include:

• Hand hygiene at the five WHO moments
• Gloves when contact with blood, body fluids, mucous membranes, or non-intact skin is anticipated
• Gown when clothing may become contaminated during care
• Mask and eye protection / face shield when splashing or spraying of body fluids is likely
• Safe injection practices — use sterile, single-use needles and syringes; never recap needles by two-hand technique
• Respiratory hygiene / cough etiquette — patients with respiratory symptoms should be masked and tissues provided
• Safe handling of sharps — dispose of immediately in puncture-resistant sharps containers at the point of care

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Transmission-Based Precautions

When a patient’s condition requires additional measures beyond standard precautions, transmission-based precautions are implemented. These are selected based on the pathogen’s known route of transmission.

Precaution Type	Pathogen Examples	Required PPE	Room Requirement
Contact	MRSA, VRE, C. difficile, scabies, RSV (pediatrics)	Gown + gloves upon entry	Private room preferred; cohorting acceptable
Droplet	Influenza, pertussis, meningococcal meningitis, SARS-CoV-2 (per current guidance)	Surgical mask within 3 feet; eye protection	Private room; door may remain open
Airborne	Tuberculosis (pulmonary/laryngeal), measles, varicella/disseminated zoster	Fit-tested N95 respirator or higher; eye protection	Airborne Infection Isolation Room (AIIR) — negative-pressure ventilation

Some conditions require combined precautions (e.g., chickenpox requires both airborne and contact precautions).

NCLEX-Style Practice Questions:

1. A patient is admitted with confirmed pulmonary tuberculosis. Which precaution type and room assignment does the nurse implement?

   • A) Contact precautions; private room with positive-pressure ventilation
   • B) Droplet precautions; private room with door closed
   • C) Airborne precautions; negative-pressure airborne infection isolation room ✓
   • D) Standard precautions; semi-private room is acceptable

2. After removing gloves while caring for a patient with Clostridioides difficile colitis, which hand hygiene method should the nurse use?

   • A) Alcohol-based hand rub — it is more effective than soap
   • B) Soap and water ✓
   • C) Antiseptic wipes are equivalent
   • D) Either method is effective for C. difficile spores

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Personal Protective Equipment (PPE)

Donning Sequence (Putting On)

PPE must be donned before entering the patient’s room or the zone of risk. The sequence is designed to protect the nurse’s most vulnerable areas first:

1. Gown — tie at neck and waist; fully cover torso and arms
2. Mask or respirator — fit snugly over nose, mouth, and chin; mold the nose wire; perform a user seal check for N95
3. Eye protection / face shield — position over face and eyes; adjust to fit
4. Gloves — pull over the cuffs of the gown

Doffing Sequence (Removing)

Doffing is the highest-risk step because the outside surfaces of PPE are contaminated. Perform hand hygiene between each removal step.

1. Gloves — grasp the outside of one glove at the wrist; peel off and hold in the gloved hand; slide fingers of bare hand under the remaining glove and peel off inside-out; dispose immediately
2. Hand hygiene
3. Gown — unfasten ties; pull away from neck and shoulders without touching the outer surface; roll inside-out and discard
4. Hand hygiene
5. Eye protection / face shield — grasp the earpieces or headband (not the front); remove and place in designated reprocessing container or discard
6. Hand hygiene
7. Mask or respirator — remove by grasping the straps or ties (not the front); dispose or place in bag for extended-use programs
8. Hand hygiene

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Medical Asepsis versus Surgical Asepsis

Concept	Medical Asepsis (Clean Technique)	Surgical Asepsis (Sterile Technique)
Goal	Reduce the number of microorganisms	Eliminate all microorganisms
When used	Routine patient care, medication administration, wound assessment	Invasive procedures: catheter insertion, wound care, IV access, surgery
Examples	Hand hygiene, clean gloves, proper disposal	Sterile gloves, sterile field, sterile instruments
Key principle	Clean to dirty; minimize contamination	Nothing non-sterile contacts the sterile field

Principles of Surgical Asepsis

1. Only sterile items may touch the sterile field
2. The sterile field must remain within the nurse’s vision at all times
3. Items held below the waist or the level of the sterile field are considered contaminated
4. The 1-inch (2.5 cm) border around the edge of a sterile drape is considered contaminated
5. Moisture transfers contamination — a wet sterile field is a contaminated field
6. When in doubt, consider it contaminated and replace it

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Isolation Procedures: Protecting Dignity

Isolation can cause patients to experience feelings of loneliness, anxiety, depression, and fear. Evidence shows that isolated patients receive fewer care contacts and are at higher risk for falls and medication errors. Nurses must proactively address the psychosocial impact of isolation:

• Explain the reason for isolation clearly and in patient-understandable language
• Perform frequent rounds and respond promptly to call lights
• Ensure patient comfort items (blankets, personal effects) are accessible
• Encourage virtual visits with family when in-person contact is restricted
• Assess for depression and anxiety; involve social work as needed
• Remove isolation precautions promptly when criteria for discontinuation are met

NCLEX-Style Practice Questions:

1. A nurse is preparing to perform a urinary catheter insertion using sterile technique. During setup, the nurse reaches across the sterile field to place an item. Which action should the nurse take?

   • A) Proceed — reaching across the field is acceptable if gloves are sterile
   • B) Establish a new sterile field ✓
   • C) Use sterile forceps to reposition the contaminated item
   • D) Add a sterile drape over the contaminated portion and continue

2. A nurse is caring for four patients. Which patient requires both contact and airborne precautions?

   • A) A patient with influenza A
   • B) A patient with MRSA wound infection
   • C) A patient with active pulmonary tuberculosis and copious respiratory secretions
   • D) A patient with disseminated varicella (chickenpox) ✓

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Standards Alignment

This section supports the following professional and regulatory frameworks:

• AACN Essentials D1, D2, D4, D6, D9: Knowledge for nursing practice; safety; population health
• NCLEX-NG CJMM: Recognize Cues (RC), Analyze Cues (AC), Prioritize Hypotheses (PH), Generate Solutions (GS), Take Action (TA)
• QSEN: Patient-Centered Care (PCC), Teamwork and Collaboration (TC), Evidence-Based Practice (EBP), Quality Improvement (QI), Safety (S)
• CCNE Standards I, II, III: Professional identity; curriculum outcomes; clinical competency
• ACEN Standards 3, 4: Student outcomes; curriculum including infection control content