Principles of Infection

1. Principles of Infection

2. What is an infection? • an infection results if pathogens increase in number and alter the functioning of normal tissues • Some infections can spread to other people -- contagious

3. Principles of Infection • understanding the basic principles of infection is essential for any health care worker in any field of health care. • Chain of Infection • Signs and Symptoms of Infection • Asepsis

4. Chain of Infection • in order for an infection to result, six factors must be present • these factors occur in a cyclical pattern • if the chain is broken, infection will not occur

5. Chain of Infection • Infectious Agent – pathogen such as a bacteria or virus. • Reservoir – a place in which the pathogen can grow and multiply eg. humans, insects, food, water • Fomites are inanimate objects contaminated with infectious material that contains pathogens • Ex: doorknobs, bedpans, linens

6. Chain of Infection • Portal of Exit – way for the pathogen to escape from the reservoir in which it has been growing. • Respiratory tract • Skin • Blood • Gastrointestinal tract • Mucous membranes

7. Chain of Infection • Mode of Transmission – way in which a pathogen can be transmitted to another reservoir. • eg. the virus that causes chickenpox can be transmitted by direct contact or airborne droplet. • Contaminated hands are one of the most common modes of transmission. • Hand washing is one of the most effective means of preventing the spread of pathogens.

8. Chain of Infection • Portal of Entry – way for the pathogen to enter the new reservoir or host. • same as the portal of exits • Respiratory tract, mucous membranes, and gastrointestinal tract are common. • injured skin

9. Chain of Infection • Susceptible Host – someone that is capable of becoming infected. • Microorganisms must be present in large enough quantity to be virulent (and cause disease). • individuals with an immunity to certain pathogens will not be susceptible • Individuals can develop immunity from either natural events, such as prior exposure, or artificial events, such as immunization

10. Signs & Symptoms of Infection • can occur when enough pathogens invade a susceptible host • Two types of infection: • at a local site of injury • generalized throughout the body

11. Signs & Symptoms of Infection • Local infections usually result from injury to the skin • Redness • Swelling • Tenderness • Warmth • drainage • Generalized infections are accompanied by fever, malaise, loss of appetite, swollen lymph nodes

12. Asepsis • aseptic techniques are used to keep an area free of pathogens • Two types: • Medical asepsis or “clean technique” • Surgical asepsis or “sterile technique”

13. Medical Asepsis • used to maintain a clean environment in order to reduce the number of microorganisms • Common medical asepsis practices: • hand washing • using personal protective equipment (PPE) like gloves • routine cleaning of the environment

14. Surgical Asepsis • used to maintain a sterile environment • no microorganisms or spores (cells produced by bacteria) • areas in the operating room are sterile • to remain sterile, only sterile items can come in contact with other sterile items