Nursing Practice: Infections and Infection Control

Infections in Nursing Practice

  • Infections are characterized as the growth of microorganisms in body tissue where they are not typically found.
  • Infectious agents can be found in various locations:
    • Water, soil, skin, intestinal tract, mouth, upper respiratory tract, vagina, and urinary tract.
  • Most microorganisms are harmless, with some even being beneficial for bodily functions.

Resident Flora and Infections

  • Normal resident flora can be beneficial in some areas but harmful in others.
    • Example: Escherichia coli (E. coli) normally inhabits the large intestine but can cause urinary tract infections.

Types of Infections

  1. Asymptomatic Infection
    • No clinical evidence but can still spread (e.g., COVID-19, tuberculosis).
  2. Local Infection
    • Limited to a specific body part (e.g., abscess, boils, urinary bladder infections).
  3. Systemic Infection
    • Spreads throughout the body (e.g., sepsis, TB).
  4. Acute Infection
    • Sudden onset, typically short-lived.
  5. Chronic Infection
    • Slow onset, lasting months or years.
  6. Nosocomial Infection (HAIs)
    • Infections acquired in a hospital; can develop during or after hospital stay.
    • Sources:
      • Endogenous: originates from the client's own flora.
      • Exogenous: originates from hospital environment or personnel.
  7. Iatrogenic Infection
    • Result from diagnostic or therapeutic procedures (e.g., bacteremia from medical procedures).

Chain of Infection

  • Infection spreads through a chain composed of six links:
  1. Etiologic Agent:
    • Microorganism capable of causing infectious disease.
    • Factors affecting virulence include pathogenicity, number of microorganisms, host susceptibility, etc.
  2. Reservoir:
    • Environment where pathogens live (humans, animals, soil, medical equipment).
    • Carrier:
      • Humans/animals carrying infections without symptoms.
  3. Portal of Exit:
    • Exit pathways for pathogens (e.g., respiratory tract, gastrointestinal tract, blood).
  4. Mode of Transmission:
    • How the microorganism is transmitted (direct, indirect, airborne).
    • Mechanisms include:
      • Direct Transmission: Immediate transfer through physical contact (touching, droplet spread).
      • Indirect Transmission: Involves contact with contaminated objects (fomites, vectors).
      • Airborne Transmission: Pathogens remain suspended in the air (e.g., tuberculosis).
  5. Portal of Entry:
    • Pathways for pathogens to enter new hosts (skin, mucous membranes).
  6. Susceptible Host:
    • Individual at risk (e.g., those with weakened immune systems, young, elderly).

Body Defenses Against Infection

Non-specific Defenses

  1. Anatomic and Physical Barriers:
    • Intact skin and mucous membranes.
  2. Inflammatory Response:
    • Localized response characterized by pain, swelling, redness, heat, and impaired function.
    • Responses to injurious agents include:
      • Physical agents (trauma, heat), chemical agents (irritants), and microorganisms (bacteria, viruses).
      • Stages of Inflammatory Response:
      • 1st: Vascular and cellular response.
      • 2nd: Exudate production.
      • 3rd: Reparative phase.

Specific (Immune) Defenses

  1. Antibody-mediated Defenses:
    • Involves B lymphocytes and antibodies.
  2. Cell-mediated Defenses:
    • Involves T-cells responding to pathogens.

Factors Increasing Susceptibility to Infection

  • Age, heredity, level of stress, nutritional status, medications, pre-existing conditions.

Asepsis in Nursing

  • Asepsis: Freedom from disease-causing microorganisms.

Types of Asepsis

  1. Medical Asepsis (Clean Technique):
    • Confines microorganisms to a specific area to limit transmission.
    • Definitions:
      • Clean: Absence of most microorganisms.
      • Dirty: Likely to contain pathogens.
  2. Surgical Asepsis (Sterile Technique):
    • Keeps areas free of all microorganisms; used for procedures involving sterile body parts.

Principles of Sterile Technique

  1. All items in a sterile field must remain sterile.
  2. Sterile items can become contaminated by non-sterile items or when out of sight or below waist level.
  3. Significant moisture penetration can lead to contamination.
  4. Skin cannot be sterilized and is considered unsterile.

Infection Prevention Practices

  • Handwashing: Effective measure for preventing infection.
    • WHO's 5 Moments for Hand Hygiene:
      • Before touching a patient, before aseptic tasks, after bodily fluid exposure, after touching a patient, after touching patient surroundings.
  • Disinfection: Use of chemical agents to reduce pathogens on surfaces.
  • Sterilization: Destroys all microorganisms using various methods (moist heat, gas, boiling water, radiation).

Standard and Transmission-Based Precautions

  1. Standard Precautions (Universal Precautions):
    • Treat all patients' blood and body fluids as potentially infectious. Practices include hand hygiene, PPE, sharps safety, cleaning, and respiratory hygiene.
  2. Transmission-Based Precautions: For patients with known or suspected infections, including airborne, droplet, and contact precautions.

Isolation Practices

  • Enacted to prevent the spread of microorganisms to healthcare personnel and visitors. Category-specific (e.g., diseases like tuberculosis) and disease-specific isolation precautions must be applied.