infection control 1

The CDC estimates that over x people a year die from x?

90,000 hospital acquired infections

about x hospital based infections are acquired each year

1.7 million

types of Microorganisms

 Bacteria

 Viruses

 Protozoa

 Prions

 Fungi

microorganisms are either…

normal microbial flora or pathogens

typical bacterium

bacteria characteristics

A very small, single celled organisms

has a cell wall

atypical nucleus that lacks a membrane

bacteria can..

grow independently and can replicate without a host cell.

what can some bacteria do?

can form endospores

(resistant form that is produced when the environment is

unfavorable. When conditions improve, they can germinate and

come back.)

examples of bacteria

tuberculosis,

streptococcal pharyngitis,

necrotizing fasciitis,

E. coli.

Rickettsia characteristics

 Considered a bacterium, but are atypical

 Smaller and just barely visible under microscope

 Only grow inside animal cells, do not survive in the environment

Rickettsia are spread by

 transmitted by infected arthropod vector bits (ticks, lice, fleas, and mites).

rickettsia can cause?

Rocky Mountain spotted fever and typhus fever

Viruses characteristics

• Subcellular organisms only visible using an electron microscope

• Viruses cannot survive independently;

• they must invade a host cell to stimulate it to forming more virus particles.

Viron

• fully developed viral particle,

• made up by genetic material, DNA or RNA

• protected by an outer coating called the capsid

virus cure

Only a few antiviral agents exist, and viruses can mutate rapidly

to become drug resistant

virus

Fungi characteristics

• Single celled yeasts

or

• long branched structures called mold that are multi-celled

yeast reproduces by

forming buds

mold reproduces by

spore formation

prions characteristics

• The smallest and least understood of all microbes.

• Infectious proteins that are capable of automatically transforming healthy proteins in nerve cells into more prions.

• Resistant to the body’s natural defenses and can cause irreversible neurologic damage.

prions

Protozoa characteristics

• Complex single celled animals that exist as free-living organisms

• Few are parasitic and live in the human body.

• They can be motile or nonmotile

protozoa can infect..

• GI system,

• genitourinary,

• respiratory,

• circulatory systems

protozoa common diseases

• Amebiasis,

• giardiasis,

• trichomoniasis,

• toxoplasmosis

nosocomial

healthcare associated infections

occur more than 48 hours of being at hospital

fungi

protozoa

about x patients die a year from nosocomial infections

90,000

sources of nosocomial infection

• contaminated hands of workers

• contaminated instruments

• urinary catheters

• invasive procedures

cycle of infection

1. Infectious organisms

2. Reservoir of infection

3. Portal of Exit

4. susceptible host

5. Portal of Entry

Infectious organisms

pathogenic organisms or pathogens

Virulence factors

factors that

• enable them to destroy or damage host cells

• resist destruction by host’s defenses

destruction of cells that organisms do allows

them to grow (stealing nutrients from cells)

cause signs & symptoms of disease

Reservoir of infection

any place pathogens can thrive to pose a threat such as

• human body(moisture, nutrients, and suitable temp)

• Damp warm places not regularly cleaned, animals, soil, water

Carriers

healthy individuals serving as reservoir without realizing

Portal of Exit

route that pathogens leave such as

• Blood, body fluids, secretions

• respiratory, urinary,

• gastrointestinal,

• infected wounds,

• bloodstream

Susceptible host

frequently patients with reduced resistance to infection

Nosocomial infection

patients that get hospital acquired infections

Occupational infections

avoid by being healthy, well-rested and standard precautions

Portal of Entry

route which microorganisms gain access into susceptible host

portal of entry examples

• respiratory system

• urinary, GI tract,

• open wounds, skin breaks, bloodstream,

• mucous membranes (eyes, mouth, nose)

six routes of transmission

1. direct contact

2. fomite

3. vector

4. vehicle

5. airborne contamination

6. droplet contamination

direct contact

host is touched by infected person and organisms are placed in direct contact with susceptible tissue

fomite

object that has been in contact with pathogenic organism

examples of fomite

X-ray table, IRs, positioning sponges, urinary catheters

vector

arthropods like mosquitoes or ticks that transport diseases

Vehicle

any medium transporting microorganisms

example of vehicles

contaminated food, water, drugs, or blood

Airborne contamination:

occurs by either dust that contains spores or by droplet nuclei (5 microns or smaller)

then inhaled by susceptible host

Droplet contamination

occurs when an infected individual coughs, sneezes, speaks, or sings near a susceptible host

examples of droplet contamination

• Involves contact with mucous membranes of the eyes, nose, or mouth of susceptible persons with large droplets (greater than 5 microns)

• Usually travel 3 feet or less but can live on objects