chapter 12

Chapter 12: Infection Control for the Sonographer

Chapter Objectives

  • Describe the cycle of infection.
  • Understand the means of transmission for several common pathogenic microorganisms.
  • Appreciate the need to use standard precautions and personal protective equipment.
  • Define the role of the sonographer in the fight against infection.

Introduction

  • Pathogen Encounter:
    • Healthcare workers encounter various pathogens daily; the risk of infection is higher due to the nature of their work.
    • A healthy immune system can combat many communicable diseases, but healthcare workers face a greater threat from more dangerous pathogens.
  • Prevention Strategy:
    • The best method to prevent the spread of infection is treating all patients as if they are carriers of pathogens.
    • Sonographers must ensure that their actions do not compromise patient health.

Infection Definition

  • An infection is defined as a condition arising when microorganisms cause injury to a susceptible host.
  • Pathogen Types:
    • Infectious diseases can be spread from one person to another.
    • Some microorganisms are beneficial, indicating that not all microorganisms are harmful.
  • Factors Affecting Pathogenicity:
    • The pathogenicity of microorganisms is influenced by various factors, such as:
    • Number of microorganisms present
    • Location where the microorganism is found
    • Existence of beneficial microorganisms, which can compete with harmful ones.

Conditions Favoring Growth of Pathogens

  • Essential Needs for Microorganisms:
    • Moisture: Most microorganisms need water to survive.
    • Nourishment: Organic matter contamination provides essential nutrients.
    • Temperature: Optimal growth often requires body temperature.
    • Darkness: Bright light can destroy certain pathogens.
    • pH: A neutral pH is generally needed along with sufficient oxygen.
    • Anaerobic Pathogens: Organisms like those causing tetanus and botulism do not require oxygen for growth.

The Cycle of Infection and Modes of Transmission

  1. Reservoir:

    • Definition: A place where organisms grow and reproduce.
    • Examples: Humans and animals are common reservoirs for pathogens.

  2. Exit from Reservoir:

    • Definition: The escape route for organisms to leave the reservoir.
    • Examples: Nose, throat, mouth, ears, intestinal tract, urinary tract, wounds.

  3. Vehicle of Transmission:

    • Definition: The means by which organisms are transported from one reservoir to another.
    • Examples: Hands, medical instruments or equipment, linens, droplets.

  4. Portal of Entry:

    • Definition: The point of entry into a new host.
    • Examples: Any break in skin or mucous membrane, mouth, nose, genitourinary tract.

  5. Susceptible Host:

    • Definition: A person who cannot repel the pathogen effectively and likely becomes ill.

Modes of Transmission

  • Pathogen Transmission:
    • For a pathogen to be transmitted from the reservoir, a portal of exit is necessary.
    • After exiting, it needs a mode of transmission which includes:
    • Contact Transmission: Can be direct or indirect.
    • Droplet Transmission: Pathogens spread via respiratory droplets.
    • Airborne Transmission: Pathogens spread through the air in particles.
    • Asymptomatic Carriers: Individuals may carry pathogens without showing symptoms.

Nosocomial and Healthcare-Associated Infections

  • Definition: Infections acquired in a healthcare setting; often preventable.
  • Common Factors Contributing to Nosocomial Infections:
    • Noncompliance or inability of healthcare workers to adhere to infection control guidelines