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Chain Of Infection

What do you know about the chain of Infection? Every healthcare professional should ideally know about the principles of Infection prevention and control. It is obvious that we can not fight an enemy without knowing what kind of enemy we are facing and what is the component of the enemy's army. I will take the chance to start with a principal component of Infection Prevention and Control namely, the Chain of Infection.

The chain of infection represents the transmission of microorganisms and subsequent infection within a health care setting, with each link in the chain representing a factor related to the spread of microorganisms. There are six components of the chain of infection and transmission does not take place unless all six elements in the chain of transmission are present.


What are the Chain of Infection Six Elements?

  1. Causative agent

  2. Reservoir of the agent

  3. Portal of exit of the agent from the reservoir

  4. Mode of transmission of the agent

  5. Portal of entry into host

  6. Susceptible host

Transmission occurs when:

  1. The agent in the reservoir exits the reservoir

  2. Through a portal of exit

  3. Travels via a mode of transmission

  4. Gains entry through a portal of entry

  5. Reach to a susceptible host

Adopted from Ottawa Public Health Website


Risk Factor For Transmission Of Infections:

  1. Infection status of client/patient/resident (including colonization)

  2. Characteristics of the client/patient/resident

  3. Type of care activities to be performed

  4. Immune status of the host

Infection Risks Assessment:

Whenever we do risk assessment for potential infection we have to consider the following potential risks:

  1. Potential contamination of skin or clothing by microorganisms in the client/patient/resident environment

  2. Potential exposure to source of infection:

  • blood, body fluids, secretions, excretions, tissues

  • non-intact skin

  • mucous membranes

  • contaminated equipment or surfaces


Colonization, Infection & Contamination

Three essential terms should be know to all healthcare professionals as they sometimes misleading and improperly used: Colonization, Contamination and Infection.


  • Presence of microorganisms in or on a host with growth but without tissue invasion or damage


  • Presence of microorganisms on non-living objects (e.g. clothing, surgical instruments), on skin or in substances (e.g., water, food, milk)


  • Entry of an infectious agent in the tissues of the host that multiplies and creates symptoms u know about the Chain of Infection?


To know more about Chain of Infection, register for the next 5-CME Credit Hour Workshop entitled "NHRA Standard Based Infection Prevention and Control". REGISTER NOW.

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