Microbiology Year 1, Semester 1

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QADRI COLLEGE OF HEALTH SCIENCES, KARACHI
“The Chain of Infection”
By: Aftab H. Abbasi
RN, DCHN, BSN, MA, LL.B
Lecturer Nursing
Qadri College of Health Sciences Karachi
QADRI COLLEGE OF HEALTH SCIENCES, KARACHI

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Date:6/21/2021 www. qadricohs.edu.pk FB Page: Qadri College of Health Sciences, Karachi, Sindh, Pakistan. 2
The Chain of Infection
As healthcare professionals, it is important
to understand two things about infection:
1- The various ways infection can be
transmitted.
2- The ways the infection chain can be
broken.

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Date:6/21/2021 www. qadricohs.edu.pk FB Page: Qadri College of Health Sciences, Karachi, Sindh, Pakistan. 3
The Chain of Infection
There are six links in the chain of infection :
1st - The Infectious Agent:
-any disease-causing microorganism
(pathogen)
2nd - The Reservoir Host:
the organism in which the infectious
microbes reside.

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Date:6/21/2021 www. qadricohs.edu.pk FB Page: Qadri College of Health Sciences, Karachi, Sindh, Pakistan. 4
The Chain of Infection
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.

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Date:6/21/2021 www. qadricohs.edu.pk FB Page: Qadri College of Health Sciences, Karachi, Sindh, Pakistan. 5
The Chain of Infection
3rd - The Portal of Exit
- route of escape of the pathogen from the
reservoir.
Examples: respiratory secretions, blood
exposure, breaks in skin

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Date:6/21/2021 www. qadricohs.edu.pk FB Page: Qadri College of Health Sciences, Karachi, Sindh, Pakistan. 6
The Chain of Infection
4th - The Route of Transmission
- method by which the pathogen gets from
the reservoir to the new host

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Date:6/21/2021 www. qadricohs.edu.pk FB Page: Qadri College of Health Sciences, Karachi, Sindh, Pakistan. 7
The Chain of Infection
Transmission may occur through:
1- The direct contact
2- Air
3- insects

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Date:6/21/2021 www. qadricohs.edu.pk FB Page: Qadri College of Health Sciences, Karachi, Sindh, Pakistan. 8
The Chain of Infection
5th - The Portal of Entry
- route through which the pathogen enters
its new host.
1- Respiratory System:
Inhalation
2- Gastrointestinal System
Ingestion

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Date:6/21/2021 www. qadricohs.edu.pk FB Page: Qadri College of Health Sciences, Karachi, Sindh, Pakistan. 9
The Chain of Infection
3- Urinary & Reproductive Tracts
Sexual contact
4- Breaks in Protective Skin Barrier

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The Chain of Infection
6th - The Susceptible Host
-the organism that accepts the pathogen
The support of pathogen life & its
reproduction depend on the degree of the
host’s resistance.

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Date:6/21/2021 www. qadricohs.edu.pk FB Page: Qadri College of Health Sciences, Karachi, Sindh, Pakistan. 11
The Chain of Infection
Organisms with strong immune systems
are better able to defend off
pathogens.

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Date:6/21/2021 www. qadricohs.edu.pk FB Page: Qadri College of Health Sciences, Karachi, Sindh, Pakistan. 12
The Chain of Infection
Organisms with weakened immune
systems are more vulnerable to the
support & reproduction of pathogens.

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Date:6/21/2021 www. qadricohs.edu.pk FB Page: Qadri College of Health Sciences, Karachi, Sindh, Pakistan. 13
The Chain of Infection
How to interrupt the chain of infection:
- The essential part of patient care & self-
protection.

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Date:6/21/2021 www. qadricohs.edu.pk FB Page: Qadri College of Health Sciences, Karachi, Sindh, Pakistan. 14
The Chain of Infection
1. Pathogen Identification
identification of infectious agent &
appropriate treatment

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Date:6/21/2021 www. qadricohs.edu.pk FB Page: Qadri College of Health Sciences, Karachi, Sindh, Pakistan. 15
The Chain of Infection
2. Asepsis & Hygiene
- potential hosts & carriers must practice
asepsis & maintain proper personal
hygiene

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Date:6/21/2021 www. qadricohs.edu.pk FB Page: Qadri College of Health Sciences, Karachi, Sindh, Pakistan. 16
The Chain of Infection
3. Control Portals of Exit
- healthcare personnel must practice
standard precautions:
(Control body secretions & wash hands
according to protocol.)

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Date:6/21/2021 www. qadricohs.edu.pk FB Page: Qadri College of Health Sciences, Karachi, Sindh, Pakistan. 17
The Chain of Infection
4. Prevent a Route of Transmission
prevent direct or indirect contact by:
1.Proper hand washing
2.Disinfection & sterilization techniques
3.Isolation of infected patients
4.Not working when contagious

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Date:6/21/2021 www. qadricohs.edu.pk FB Page: Qadri College of Health Sciences, Karachi, Sindh, Pakistan. 18
The Chain of Infection
5. Protect Portal of Entry
-Health professionals must make sure
that ports of entry are not subjected
to pathogens.
(nose, mouth, eyes, urinary tract, open
wounds, etc.)

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Date:6/21/2021 www. qadricohs.edu.pk FB Page: Qadri College of Health Sciences, Karachi, Sindh, Pakistan. 19
The Chain of Infection
6. Recognition of Susceptible Host
health professionals must recognize &
protect high-risk patients.
• Cancer Patients
• AIDS Patients
• Transplant Patients
• Infant & Elderly Patients

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Date:6/21/2021 www. qadricohs.edu.pk FB Page: Qadri College of Health Sciences, Karachi, Sindh, Pakistan. 20
The Chain of Infection
Remember--breaking the chain of
infection is the responsibility
of each health professional.

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Date:6/21/2021 www. qadricohs.edu.pk FB Page: Qadri College of Health Sciences, Karachi, Sindh, Pakistan. 21
QADRI COLLEGE OF HEALTH SCIENCES, KARACHI
By: Aftab H. Abbasi
RN, DCHN, BSN, MA, LL.B
Lecturer Nursing
Qadri College of Health Sciences Karachi