1. The Chain of Infection

2. The various ways infection can be transmitted.
As healthcare professionals, it is important to understand two facts about infection:
The various ways infection can be transmitted.
2. The ways the infection chain can be broken.

3. There are six links in the chain of infection: 1. Causative agent 2
There are six links in the chain of infection: 1. Causative agent 2. Source or reservoir 3. Portal of exit 4. Mode of transmission 5. Portal of entry 6. Susceptible host

4. 1st - The Infectious Agent
-Any disease-causing microorganism (pathogen)

5. Microorganism
A small, living plant or animal not visible to the naked eye

6. Pathogens vs. Nonpathogens
Nonpathogens are beneficial microorganisms that are found on and in the human body
Pathogens cause disease/infection

7. Class I - Bacteria Multiply rapidly
Classified by shape and arrangement

8. Cocci Round or spherical in shape
If Cocci occur in pairs they are diplococci
If Cocci occur in chains they are streptococci
If Cocci occur in clusters or groups they are staphylococci

9. Cocci Cocci are the most common pus-producing microorganisms
Diplococci bacteria cause diseases such as Gonorrhea, Meningitis, & Pneumonia.
Streptococci bacteria cause diseases such as Strep throat and Rheumatic fever.

10. Staphylococci Can cause infections such as Boils Wound infections
Toxic shock

11. Bacilli
Rod shaped
Occur singly, in pairs, or in chains

12. Bacilli
Many bacilli contain flagella, threadlike projections that are similar to tails and allow organisms to move
Bacilli have the ability to form spores, thick walled capsules. In the spore form, bacilli are extremely difficult to kill.

13. Diseases caused by different types of bacilli include:
Tuberculosis
Tetanus
Pertussis
Whooping cough
Botulism
Diphtheria
Typhoid

14. Class II - Protozoa
one-celled animals often found in decayed materials and contaminated water.

15. Class III - Fungi
simple, plantlike organisms that live on dead organic matter.

16. Two common fungi forms:
Yeasts
Molds

17. Fungi cause diseases such as:
Ringworm
Athlete’s foot
Histoplasmosis
Thrush

18. Class IV - Rickettsiae
(ri-ket-se-a) parasitic microorganisms which means they cannot live outside the cells of another living organism.
Commonly found in
fleas, lice, ticks, mites

19. Rickettsiae
transmitted to humans by the bites of these insects (typhus fever, rocky mountain spotted fever).

20. Class V - Viruses
Difficult to kill because they are resistant to many disinfectants and antibiotics.
Smallest microorganism
Cause diseases such as
Common cold
Measles, Mumps
Influenza
Chicken pox
Warts

21. -The organism in which the infectious microbes reside
2nd - The Reservoir Host
-The organism in which the infectious microbes reside

22. What are “Carrier Hosts?”
Hosts that do not show any outward signs or symptoms of a disease, but are still capable of transmitting the disease are known as carriers.

23. -Route of escape of the pathogen from the reservoir
3rd - The Portal of Exit
-Route of escape of the pathogen from the reservoir
Examples: respiratory secretions, blood exposure, breaks in skin

24. 4th - The Route of Transmission
Method by which the pathogen gets from the reservoir to the new host
direct contact
air
insects

25. 5th - The Portal of Entry
Route through which the pathogen enters its new host
Respiratory System (inhalation)
Gastrointestinal System (ingestion)
Urinary & Reproductive Tracts (sexual contact)
Breaks in Skin (Protective Barrier)

26. 6th - The Susceptible Host
The organism that accepts the pathogen
The support of pathogen life and its reproduction depend on the degree of the host’s resistance.
Organisms with strong immune systems are better able to fend off pathogens.
Organisms with weakened immune systems are more vulnerable to the support and reproduction of pathogens.

27. How to interrupt the chain of infection:
Pathogen Identification: identify infectious agent and appropriate treatment
Asepsis and Hygiene: potential hosts and carriers must practice asepsis and maintain proper personal hygiene
Control Portals of Exit: Healthcare personnel must practice standard precautions (Control body secretions and wash hands according to protocol.) -

28. 4. Prevent a Route of Transmission
Prevent direct or indirect contact by
Proper hand washing
Disinfection & sterilization techniques
Isolation of infected patients
Not working when contagious

29. 5. Protect Portal of Entry
Healthcare professionals must make sure that ports of entry are not subjected to pathogens.
(nose, mouth, eyes, open wounds, etc.)

30. 6. Recognition of Susceptible Host
Healthcare professionals must recognize and protect high-risk patients. Cancer Patients
AIDS Patients
Transplant Patients
Infants
Elderly Patients

31. “Remember--breaking the chain of infection is the responsibility
of each healthcare professional.”