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
There are six
links
in the chain of
infection :
1st - The Infectious Agent
-any disease-causing
microorganism
(pathogen)
Infection Control
• Microorganism – a small living organism that is not visible to the naked eye; found everywhere in the environment
• Normal flora-plant life adapted for living in a specific environment; important for maintaining certain body processes; nonpathogenic
• Pathogen-disease or infection causing microorganism
Types of Microorganisms
• Bacteria• Simple, one-celled organisms that multiply
rapidly
• Classified by shape and arrangement (cocci,
bacilli, spirilla
• Examples of disease caused by bacteria
include gonorrhea, meningitis, strep throat,
botulism
• Antibiotics are used to kill bacteria
Types of Microorganisms
• Protozoa
• One-celled animal-like organisms often
found in decayed materials and
contaminated water
• Cause diseases such as malaria, amebic
dysentery, trichomonas
Types of Microorganisms
• Fungi
• Simple, plant-like organisms that live on
dead organic matter
• Yeasts and molds are two common forms
that can be pathogenic
• Cause diseases such as ring worm,
athlete’s foot, yeast vaginitis, and thrush
• Treated with antifungals
Types of Microorganisms
• Rickettsiae
• Parasitic microorganisms commonly found
in fleas, lice, ticks, and mites
• Cause diseases such as typhus fever,
Rocky Mountain Spotted fever
• Antibiotics are effective against many
rickettsiae
Types of Microorganisms
• Virus
• Smallest microorganism, visible only with an
electron microscope
• Cannot reproduce unless inside another living
cell
• More difficult to kill because resistant to many
disinfectants and are not affected by antibiotics.
• Cause diseases such as common cold, herpes,
chicken pox, AIDS, Hepatitis
2nd - The Reservoir Host
-the organism in which the
infectious microbes reside
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.
What are “Carrier Hosts”
3rd - The Portal of Exit
-route of escape of the pathogen
from the reservoir.
Examples: respiratory
secretions, blood
exposure, breaks in
skin
4th - The Route of
Transmission
-method by which the pathogen
gets from the reservoir to the
new host
Transmission may occur through:
direct contact
air
insects
5th - The Portal of Entry
-route through which the
pathogen enters its new host
Respiratory System
Gastrointestinal System
Urinary & Reproductive Tracts
Breaks in Protective Skin Barrier
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.
Organisms with strong immune
systems are better able to fend off
pathogens.
Organisms with weakened immune
systems are more vulnerable to the
support & reproduction of pathogens.
-The essential part of patient care &
self-protection.
How to interrupt the chain of
infection:
1. Pathogen Identification
-identification of infectious
agent & appropriate treatment
2. Asepsis & Hygiene
-potential hosts &
carriers must practice
asepsis & maintain
proper personal hygiene
3. Control Portals of Exit
-healthcare personnel must
practice standard precautions any
time they might possibly come into
contact with blood or other body
fluids :
(Control body secretions & wash
hands according to protocol.)
4. Prevent a Route of
Transmission
-prevent direct or indirect contact by:
1. Proper handwashing (#1 way to
prevent the spread of infection!)
2. Disinfection & sterilization techniques
3. Isolation of infected patients
4. Not working when contagious
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.)
6. Recognition of Susceptible
Host
-health professionals must recognize
& protect high-risk patients
•Cancer Patients
•AIDS Patients
•Transplant Patients
•Infant & Elderly
Patients
The Chain of Infection
Reservoir Host
Portal of Exit
Mode of TransmissionPortal of Entry
Susceptible Host
Infectious Agent
Chain of infection
• Infectious agent Reservoir Host Portal
of Exit Mode of Transmission Portal
of Entry Susceptible host…..and back
to the infectious agent!
How to Don a Gown
• Select appropriate type and size
• Opening is in the back
• Secure at neck and waist
• If gown is too small, use two gowns
Gown #1 ties in front
Gown #2 ties in back
PPE Use in Healthcare Settings
How to Don a Mask
• Place over nose, mouth and chin
• Fit flexible nose piece over nose bridge
• Secure on head with ties or elastic
• Adjust to fit
PPE Use in Healthcare Settings
How to Don Eye and Face Protection
• Position goggles over
eyes and secure to the
head using the ear pieces
or headband
• Position face shield over
face and secure on brow
with headband
• Adjust to fit comfortablyPPE Use in Healthcare Settings
How to Don Gloves
• Don gloves last
• Select correct type and size
• Insert hands into gloves
• Extend gloves over isolation gown cuffs
PPE Use in Healthcare Settings
“Contaminated” and “Clean” Areas of PPE
• Contaminated – outside front
Areas of PPE that have or are likely to have
been in contact with body sites, materials, or
environmental surfaces where the infectious
organism may reside
• Clean – inside, outside back, ties on
head and back
Areas of PPE that are not likely to have been in
contact with the infectious organismPPE Use in Healthcare Settings
Sequence for Removing PPE
• 1st: Gloves
• 2nd: Face shield or goggles
• 3rd: Gown
• 4th: Mask or respirator
PPE Use in Healthcare Settings
How to Remove Gloves (1)
• Grasp outside edge near
wrist
• Peel away from hand,
turning glove inside-out
• Hold in opposite gloved
hand
PPE Use in Healthcare Settings
How to Remove Gloves (2)
• Slide ungloved finger
under the wrist of the
remaining glove
• Peel off from inside,
creating a bag for
both gloves
• Discard
PPE Use in Healthcare Settings
Remove Goggles or Face Shield
• Grasp ear or head
pieces with ungloved
hands
• Lift away from face
• Place in designated
receptacle for
reprocessing or
disposalPPE Use in Healthcare Settings
Removing Isolation Gown
• Unfasten ties
• Peel gown away from
neck and shoulder
• Turn contaminated
outside toward the
inside
• Fold or roll into a
bundle
• Discard
PPE Use in Healthcare Settings
Removing a Mask
• Untie the bottom,
then top, tie
• Remove from face
• Discard
PPE Use in Healthcare Settings
Hand Hygiene
• Perform hand hygiene immediately after
removing PPE.
If hands become visibly contaminated during PPE
removal, wash hands before continuing to remove
PPE
• Wash hands with soap and water or use
an alcohol-based hand rub
PPE Use in Healthcare Settings
* Ensure that hand hygiene facilities are available at
the point needed, e.g., sink or alcohol-based hand
rub
What Type of PPE Would YouWear?
• Giving a bed bath?
• Suctioning oral secretions?
• Transporting a patient in a wheel chair?
• Responding to an emergency where blood is spurting?
• Drawing blood from a vein?
• Cleaning an incontinent patient with diarrhea?
• Irrigating a wound?
• Taking vital signs?
PPE Use in Healthcare Settings
***Answer these questions on a separate sheet of paper and turn
in***