Chapter 4 - Infection control

• Chain of Infection


  The spread of an infection within a community described as a series of interconnected steps that describe how a pathogen moves about
• Infection control


  Efforts to break the chain of infection and prevent a pathogen from spreading
• Contact tracing


  Efforts to break the chain of infection and prevent a pathogen from spreading
• Emerging infectious diseases


  Diseases whose incidence in humans has increased in the past two decades or are a threat to increase in the near future
• Chain of Infection


  1. Infectious agent (pathogen)

  2. Reservoir (normal location of pathogen)/source

  3. Portal of exit from reservoir

  4. Mode of transmission

  5. Portal of entry into host

  6. Susceptible host
• Infectious agents (pathogens)


  • Include bacteria, viruses, fungi, and parasites
  • Virulence depends on number, potency, ability to enter/survive in body, and host susceptibility
• Reservoir


  Any person, animal, arthropod, plant, soil or substance in which an infectious agent normally lives and multiplies
• Portal of exit


  The way the infectious agent leaves the reservoir (through open wounds, aerosols, body fluid splatter)
• Modes of transmission


  • Direct contact
  • Droplet spread
  • Indirect transmission
  • Airborne transmission
  • Vehicles (food, water, biological products, fomites)
  • Vectors (mosquitoes, fleas, ticks)
• Portal of entry


  The manner in which a pathogen enters a susceptible host, often the same as the portal of exit from the source
• Host


  The final link in the chain, a susceptible individual whose genetic makeup, immunity, and other factors affect their ability to resist infection
• Asepsis


  The absence of disease-producing microorganisms
• Aseptic technique


  Efforts to minimize the onset and spread of infection
• Types of asepsis technique

  • Medical asepsis (clean technique)
  • Surgical asepsis (sterile technique)
• Medical asepsis


  • Measures used to prevent the spread of organisms from place to place
  • Aims to reduce the number or spread of microorganisms
• Examples of medical asepsis

  • Changing client's bed linen daily
  • Handwashing
  • Barrier techniques
  • Routine environmental cleaning
  • Isolation techniques
• Surgical asepsis


  • Procedures used to keep objects or areas sterile from microorganisms
  • An object or area is considered contaminated if touched by something not sterile
• Cornerstones of surgical asepsis

  • Know what is sterile
  • Know what is not sterile
  • Keep the two apart
  • Remedy contamination immediately
• Principles of surgical asepsis

  • Always face the sterile field
  • Do not turn back or side on a sterile field
  • Keep sterile equipment above waist level
  • Do not speak, sneeze or cough over sterile field
  • Never reach across sterile field
  • Keep unsterile objects away from sterile field
  • Keep sterile field dry
  • Handle liquids cautiously near sterile field
  • Clearly label sterile supplies
  • Never assume an object is sterile
  • Avoid sweeping and dusting when sterile supplies are open
• Procedures included in surgical asepsis

  • Surgical hand scrub
  • Donning a gown
  • Applying and removing sterile gloves
  • Sterilization of equipment