Foundational Concepts Modules – Infection Control and Isolation: infection

Chain of infection

sequence of factors needed for an infection to occur. Infectious agent → reservoir → portal of exit from reservoir → mode of transmission → portal of entry → susceptible host

Infectious agent

something that contains bacterium, fungus, virus, parasite, or prion.

Resident flora

bacteria that live in or on a client and help protect the body from infection. Can become infectious agent when moved to different part of the body.

Flora infectious agent example

GI tract move somewhere else

To break chain of infection at the infectious agent stage

infectious pathogens must be destroyed this can be by disinfecting, sterilizing, cleaning/ antimicrobial treatment

reservoir

habitat of infectious agent, it lives, grows, reproduces, and replicates itself.

Example of reservoirs

people, insects, birds, animals, soil, water, food, IV fluids, feces

Humans may not always manifestations of disease

can still pass pathogen along to new host

To break chain of infection on reservoir stage in healthcare setting

proper hand hygiene, pt receive preoperative skin prep prior to surgery and clinical or surgical environment should be cleansed properly

Portal of exit

route infectious pathogen can leave reservoir. Can be the same as portal of entry

Examples of port of exit (infectious agent can replicate or toxin can act here still)

ears, nose, mouth, blood, skin, bodily fluid

Break chain of infection through the portal of exit

containment of body fluids, drains, dressing, or methods to decrease body secretion

Modes of transmission

contact, droplet, airborne, vehicle, vector borne. Can be spread by several ways.

Break chain of infection through transmission modes

hand hygiene and proper barrier devices by eliminating them

Portal of entry

required for pt to get infection, body orifice. Place for infectious agent to enter so it can replicate or its toxins can act

Influenza

virus enters and exits through the respiratory tract.

Body orfice

ears, nose, mouth, breaks in mucous membrane or skin

Susceptible host

required for infectious agents to take hold and become reservoirs.

Not everyone exposed will become sick from infectious agent

some may not even exhibit symptoms some may

Break chain of infection at susceptible host

increase host’s line of defense like immunizations, proper nutrition, dietary supplements, proper hygiene, control of blood sugar

Factors that contributes to how host reacts to infectious agent

level of immunity, sleep, diet, interactions with pathogens present in body and virulence of infectious agent

Very efficient at making people sick

more potent or more virulent than other infectious agents

Three main modes of transmission

droplet, air, contact

Contact

transmitted by contact with an object or a person ex) HSV.

indirect transmission

from one person to another through a contaminated object, Staphylococcus aureus

Droplet

transmitted through large droplets from activities like coughing, sneezing or singing. From someone to the mucosa of another. Bordetella pertussis, covid, flu, norovirus

Airborne

transmitted through small particulates in air. TB, rubeola (measles), varicella (chickenpox), (flu can be and rotavirus can be but usually through droplet)

Vector

transmitted through insects (mosquitos and rats)

Vehicles

transmitted through contaminated water, contaminated items to multiple individuals e.coli

Specific types of defense

physical and chemical barriers, nonspecific immunity and specific immunity

Skins is the largest organ

primary defense mechanisms

Skin three major functions

reduce loss of water, protect against abrasions and micro organism, provide a permeable barriers against the environment

Stratum corneum

lipid layer of skin, reducing water loss, half of layer restored in 6hrs but full takes 5 to 6 days.

Detergents and adhesive tapes

destroy stratum corneum

Mucous membrane

secretes mucus to protect body from invaders.

Others that help remove waste from body

tears, swear, WBC, cilia (prevents from entering respiratory) coughing, acids and enzymes in gi tract, pH

Nonspecific immunity

WBC (neutrophils and macrophages) works as phagocytes. Released during inflammatory response

Phagocytes

eat and destroy micro organism

Specific immunity

antibodies (immunoglobulins) and lymphocytes

Antibodies

bind to infectious agents and activated WBCs and complements to destroy and infectious agent