Infection Control and Isolation Flashcards
Chain of infection requirements
Presence of infectious agent, available reservoir, a portal of exit from the reservoir, mode of transmission from reservoir to host, and portal of entry to host
Infectious agent
Something containing virus, bacteria, parasite, or fungus, or prion.
Reservoir
habitat where infectious agent lives
can be animate (human, animal) or inanimate (medical equipment, food, contaminated soil or water)
Portal of exit
Route where infectious agent leaves the reservoir
Body orifice or skin, blood and body fluids
To break chain of infection at portal of exit: contain body fluids and decrease secretions
Modes of transmission
Contact, droplet, airborne, vehicle, and vector-borne transmission
Break chain of infection here with hand hygiene and PPE
Portal of entry
How infectious agent enters host
Body orifice, breaks in skin
Can be the same as the portal of exit (for example, resp tract)
How can you decrease host susceptibility
Increase host line of defense: vaccination, hand hygiene, nutrition, blood glucose control
What affects whether a host will become ill after being infected?
- Whether the host is healthy at the time of infection (including diet and sleep)
- Interactions with other pathogens in the body and virulence of the infectious agent
What increases host susceptibility?
- age
- immunosuppressants and other medicaations
- HIV/AIDS
- cancer
- transplant
- radiation therapy
- devices in the body (IVs, catheters, implants)
What are the 3 modes of transmission of an infectious agent?
- Contact
- Droplet
- Airborne
What is direct contact transmission?
Pathogens move directly from one person to another
Ex: patient’s blood comes in contact directly with nurses’s skin.
What is indirect contact transmission?
Transmission from an infected person to another through a contaminated object or person
Ex: PPE that is not removed between patients can transmit infectious agents between patients
What is droplet transmission?
Infectious droplets travel through the air and come in contact with the mucosa of the host.
droplets can be released by CPR, intubation, and chest physiotherapy
What is airborne transmission?
Small infectious particles move into the airspace of another person (they can travel longer distances)
Examples: TB, measles, and chickenpox
Vehicle transmission
transmission from contaminated ITEMS to MULTIPLE people
Ex: Lettuce gets contaminated with E.Coli and causes an outbreak.
Vector-borne transmission
Transmission of infectious agents through animals, including insects.
What are physical barriers to infection?
- SKIN (reduces water loss, protects against abrasion and microorganisms, and creates a permeable barrier against the environment)
- Mucous membranes (humidification can be added to O2)
- tears, sweat and WBCs remove waste from the body
- cilia in respiratory tract prevent pathogens from entering
What are chemical barriers to infection?
- unfavorable pH (vagina)
- Acids and enzymes in GI tract destroy some pathogens
Nonspecific immunity
Neutrophils and macrophages (which work as phagocytes and are released during inflammatory response)
Specific immunity
Antibodies and lymphocytes
Inflammatory response steps
- Recognition of harmful stimuli by pattern receptors on surface of cells
- Activation of inflammatory pathway
- Release of inflammatory markers
- Recruitment of inflammatory cells
What are cytokines?
Hormones secreted by macrophages during inflammatory response, which attract immune cells to the injured site and activate cells involved in tissue repair
How do antihistamines work?
They block histamine, which is released from mast cells during inflammatory response
What are signs and symptoms of inflammation?
Pain, swelling, redness, and heat
What are potential outcomes of inflammatory response?
- Infection/wound heals locally
- Infection spreads to lymph
- Infection spreads to blood (sepsis)
What causes swelling in inflammation?
Plasma from the blood enters the site
What causes pain in infection?
Swelling from increase in plasma puts pressure on nerves in the area
What is pus?
WBCs and destroyed pathogens
How does vasodilation occur in the inflammatory response?
Stimulated by histamine, kinins, and prostaglandins in order to bring more WBCs to the site
What are the stages of infection?
- Incubation
- Prodromal
- Acute illness
- Period of decline
- Period of convalescence
Incubation stage
The time between exposure and first symptoms. Labs may detect infection at this stage
Prodromal stage
Infectious agent replicates and pt starts to have symptoms (fever, aches, etc.)
Acute illness stage
Specific infectious disease process becomes clearer
Period of decline
Signs and symptoms start to decline
Period of convalescence
Return to a previous state of health, or a new state of health if the infection has left lasting effects.
Local infections
confined to an area of the body and can be treated with oral and topical abx
Systemic infection
Start local then move into blood. Requires IV abx and monitoring.
Function and expected lab value of neutrophils
- first responder and phagocytic
- 55-70%
Fxn and expected lab value of lymphocytes
- fight chronic bacterial infections and acute viruses
- 20-40%
Fxn and expected lab value of monocytes
- phagocytes that clean tissue damage, enhance immune response
- 2-8%
Fxn and expected lab value of eosinophils
- active in allergic reactions and parasitic infections
- 1-4%
Fxn and expected lab value of basophils
- release histamine, serotonin, and heparin (increase blood flow and reduce clotitng)
- can perform phagocytosis
- 0.5-1%
Medical asepsis
Reduction of disease-causing microorganisms to reduce infection risk (such as isolation precautions)
surgical asepsis
Techniques to make sure surgical items are sterile, as well as other equipment that may come in contact with the patient like gloves. This prevents SSIs
Sterilization
Eradication of all microorganisms, including spores, through cleaning such as steam and dry heat, ethylene oxide gas, or chemicals.
Sterile fields
Work surface close to pt and 12-18 inch away from other objects like tables and walls. Packaging of supplies should be checked for tears. Outer in inch border of field is contaminated so items should be placed in the middle
Disinfection
Cleans instruments so ALMOST all microorganisms are eradicated. high level (some spores remain) - pasteurization or chemicals for procedural equipment low level (spores, and some fungi and viruses remain) - hospital grade cleaning products for pt room items
