Infection Control

What Are The Stages Of The Infection Cycle/Chain Of Infection?

Infectious Agent

Reservoir

Portal Of Exit

Portal Of Entry

Mode Of Transmission

Susceptible Host

What is a susceptible host?

A person whose defenses can not successful resist the organism

What is an infectious agent?

the pathogen itself capable of causing an infection , like viruses, bacteria, prions, and fungi

What is the mode of transmission?

how infectious microorganisms move to another host, whether by contact, droplet, airborne or vector.

What is a portal of entry?

point at which organisms enter a new host

What is a portal of exit?

point of escape for the organism from the reservoir

What is a reservoir?

natural habitat of the organism where it lives and multiplies

What factors increase host susceptibility?

Age

Underlying disease: HIV/AIDS

Malignancy

Transplants

Medications

Surgical procedures

Radiation therapy

Indwelling devices: endotracheal tubes, urinary catheters, central venous catheters

What are the stages of infection?

1) Incubation

2) Prodromal

3) Full/Acute Stage

4) Convalescence

What is the incubation period?

Pathogen is multiplying; no symptoms yet

What is the prodromal stage?

vague, general symptoms - the person is most contagious here

What is the Full/Acute stage?

Specific signs and symptoms of the illness are present

What are the body's defenses?

Physical and Chemical Barriers

Non-Specific Immunity

Specific Immunity

What are physical and chemical barriers

skin and mucosal membranes

What is nonspecific immunity?

This includes cells such as neutrophils and macrophages (phagocytes) that eat and destroy invaders, providing broad protection.

What is specific immunity?

Antibodies and lymphocytes target and remember specific pathogens, making future responses faster and stronger.

What is the inflammatory response?

the body's natural defense against injury or infection, triggered by pathogens (like bacteria or viruses) or noninfectious causes (injury, chemicals, psychological factors)

steps of inflammation

1. Recognition of harmful stimuli by pattern receptors (located on the surface of cells)

2. Activation of the inflammatory pathway

3. Release of inflammatory markers

4. Recruitment of inflammatory cells

Modes of transmission

contact (direct or indirect)

droplet

airborne

vehicle

vector

What is indirect contact transmission?

spreads to a host by a nonliving object called a fomite

What is direct contact transmission?

person to person

airborne transmission

occurs through contact with contaminated respiratory droplets spread by a cough or sneeze

droplet transmission

Transmission via airborne droplets that come into contact with the mucosa of a host.

What is vehicle transmission?

Transmission of infectious agents to various individuals through a common source, such as contaminated food or water.

What is vector transmission?

Transmission of infectious agents through animals, such as an insect or rodent.

What is medical asepsis/clean technique?

measures used to reduce and prevent the spread of pathogens

What is surgical asepsis (sterile technique)?

Practices used to render and keep objects and areas free from microorganisms.

What are standard precautions?

They are used during every patient interaction. Includes: hand hygiene, use of PPE, respiratory hygiene, safe injection practices, and disinfection of soiled surfaces and equipment.

What are the key measures of airborne precautions?

Private room with negative air pressure and 6-12 air changes/hr; door closed; wear a fitted respirator on entry (unless immune, for measles/varicella); mask the patient during transport.

PPE Worn

N-95

Gloves

Gown

What are some airborne diseases?

TB, varicella, measles

What are contact precautions?

private room, gown, and gloves

What are contact diseases?

C. Diff

MRSA

VRE

What are droplet precautions?

Mask, gloves, eye protection, and gown

What are droplet diseases?

1. seasonal influenza virus

2. mumps

3. Rubella virus

4. pertussis

5. diphtheria