Infection Control & Isolation Flashcards
chain of infection
a chain of necessary pieces needed for an infection to occur and includes the following links:
1. infectious agent
2. reservoir
3. portal of exit
4. mode of transmission
5. portal of entry
6. susceptible host
A break in any of the links of this chain can prevent the development of an infection.
infectious agent
something that contains bacteria, fungi, virus, parasite, prion.
resident flora
the bacteria that live on or in a client and help protect the body from infection.
…can become an infectious agent when moved to a different location of the body; for example, flora from the gastrointestinal tract can move elsewhere in the body and create infection there.
reservoir
the habitat of the infectious agent; a location where it can live, grow, and reproduce itself or replicate.
portal of exit
means by which the infectious agent can leave the reservoir.
can be any body orifice - ears, nose, mouth…
other portals of exit include blood or body fluids that leave the body through the gastrointestinal tract, respiratory tract, skin…
mode of transmission
the moving of bacteria, viruses, fungi, parasites, and prions from place to place. These are contact, droplet, airborne, vehicle, and vector-borne transmission.
portal of entry
any body orifice that provides a place for the infectious agent to enter and replicate or for the toxin to act.
susceptible host
required for the infectious agent to take hold and become a reservoir for infection. Not everyone who is exposed to an infectious agent will get ill. Some people never exhibit manifestations at all but can become colonized (temporarily or permanently) with the infectious agent.
Factors that increase host susceptibility
Age
Underlying disease
HIV/AIDS
Malignancy
Transplants
Medications: immunosuppressants, antirejection medications, antineoplastics, antimicrobials, corticosteroids, gastric suppressants (e.g., proton pump inhibitors)
Surgical procedures
Radiation therapy
Indwelling devices: endotracheal tubes, urinary catheters, central venous catheters, arterial catheters, and implants such as pacemakers and artificial joints.
Three main modes of transmission
contact
droplet
airborne
contact transmission
transmitted by contact with an object or a person
droplet transmission
transmitted through droplets from activities such as coughing, sneezing, and singing.
airborne transmission
transmitted through the air
vector transmission
transmitted by insects
vehicle transmission
transmitted by contaminated water
direct contact transmission
occurs when microorganisms are directly moved from an infected person to another person, rather than through a contaminated object or person.
Example: a client’s blood coming in contact with an open abrasion on a nurse’s skin. If a nurse is caring for a client who has scabies and is not wearing gloves, the scabies mites can directly contact the nurse’s skin.
indirect contact transmission
occurs when microorganisms are directly moved from the infected person to another person with having a contaminated object or person between these two.
personal protective equipment (PPE)
specially designed equipment that is meant to protect the health care worker from contamination, blood, or body fluids. This equipment may include masks, eye protection, gown, gloves, and hair caps. Equipment that should be put on (donned) prior to client interactions to prevent the spread of infectious organisms and can include gloves, gowns, masks, eye and face protection, and shoe covers.
droplet transmission
occurs when droplets from the respiratory tract of a client travel through the air and into the mucosa of a host.
Pathogens transmitted via droplets
influenza virus
Bordetella pertussis
Medical procedures can release droplets into the air.
cardiopulmonary resuscitation (CPR)
endotracheal intubation
chest physiotherapy
The exact distance over which droplet transmission occurs depends on the specific infectious agent.
Other factors that affect spread through this route include humidity and air temperature.
Clients can transmit the infection via droplet transmission if they have:
norovirus
rhinovirus
coronavirus
influenza
pertussis
airborne transmission
occurs when small particulates move into the airspace of another person and carry infectious agents.
These particles remain in the air and can travel over relatively long distances, leading to the potential for others outside the client’s room to inhale them.
Clients with airborne infections require placement in a private room with negative air pressure.
Examples of infections caused by airborne transmission
tuberculosis
rubeola (measles)
varicella (chickenpox)
Some infections that are primarily transmitted through the droplet route have been found to be airborne under certain conditions.
influenza; rotavirus.
But do not require clients to be placed in a negative-pressure environment because droplet precautions are adequate to prevent their spread.
vector-borne transmission
transmission of infectious agents through animals, such as an insect or a rodent.
While they are not infected with the pathogen themselves, they can carry microorganisms from one location or person to individuals.
Three specific types of defenses
physical and chemical barriers
nonspecific immunity
specific immunity
The skin performs three major functions:
- reduce loss of water
- protect against abrasion and microorganisms
- provide a permeable barrier against the environment
Keeping the lipid layer (the stratum corneum) of the skin intact is key to:
reducing water loss and helping the body fight infection.
What can destroy the lipid layer?
Detergents, though it regenerates quickly.
Approx. half of the lipid layer is restored in how many hours and fully restored in how many days after being destroyed?
6 hours; 5 to 6 days.
Use of humectants promotes:
hydration and improves skin integrity; found in lotions and hand creams.
What aids in removing waste from the body?
tears, sweat, and white blood cells
The respiratory tract contains what structures that help prevent particulates from entering the body?
cilia — short hair-like projections
What is the GI tract’s function in infection control?
secreting acids and enzymes that can destroy or neutralize some foreign invaders. Even the natural flora helps limit the transmission and overgrowth of some bacteria.
nonspecific immunity
comprised of neutrophils and macrophages and their work as phagocytes.
Phagocytes eat and destroy microorganisms, which helps protect the body from harm. Both neutrophils and macrophages are released during the inflammatory response.
specific immunity
refers to the work of antibodies (also called immunoglobulins) and lymphocytes.
What do antibodies specifically do?
bind to infectious agents and activate the white blood cells and complement to destroy the infectious agent.
inflammatory response
natural defense of the body when injured, when foreign substances are present, or when infectious agents attack.
Basic steps of inflammation
- recognition of harmful stimuli by pattern receptors (located on the surface of cells)
- activation of the inflammatory pathway
- release of inflammatory markers
- recruitment of inflammatory cells
Inflammatory response (two categories)
- infectious
- noninfectious
infectious triggers
viruses
bacteria
fungi
etc.
noninfectious triggers
physical triggers such as burns, frostbite, foreign bodies that have entered the body, trauma, injury, and radiation.
chemical triggers such as irritants (e.g., fluoride, nickel), fatty acids, alcohol, toxins, and glucose.
biological triggers such as damaged cells.
psychological triggers, such as excitement.
