Download Infection Control & Microorganisms

Infection Control
&
Microorganisms
Medical & Surgical Asepsis
Universal Precautions
Basic Concepts & Goals
• Microorganisms = minute living organisms that are too small to see
– Non-pathogenic= those that do not cause disease
– Pathogenic = those that cause disease ( also called Pathogens)
– Types: (see next slide)
» Viruses
» Rickettsiae & chlamydia
» Bacteria
» Fungi
» Parasites
• Goals of infection control = TO USE ASEPTIC TECHNIQUE
1. Prevent the spread of pathogens
2. Achieve asepsis (note: asepsis means absence of pathogens)
– Medical asepsis = killing of pathogens AFTER they leave the body
– Surgical asepsis = killing of pathogens BEFORE they enter the body
3. Educate the public
Asepsis
Absence of Pathogens
•
Mainstay of medical asepsis = handwashing
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Main method of removing pathogens after they leave the body
Sanitation & disinfection are part of medical asepsis
•
Mainstay of surgical asepsis = sterilization
•
3 basic ways to provide aseptic control
1. Sanitation ----- soap & water wash
2. Disinfection --- use of chemicals to destroy most (not all)
pathogens
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3.
Antiseptics – used on people (exp: alcohol, betadine)
*** HANDWASHING
Disinfectants – used on objects (exp: bleach)
Sterilization -- destroys all microorganisms
•
Use autoclave ---- steam under pressure
Handwashing
• 2 types: Medical handwashing & Surgical handwashing
• Key points for medical handwashing
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Turn on faucets with dry towel
Keep fingers pointing down
Clean nails
Turn off faucets with dry towel
The Factors in an Infectious Process
Chain of Infection
•Infectious Agents
•Reservoir
•Portal of Exit
•Means of
Transmission
•Portal of Entry
•Susceptible Host
using example of German Measles
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Pathogen
Reservoir/Source(Original Host)
“Portal of Exit” from Source
Means of Transmission to New Host
“Portal of Entry” into New Host
Susceptible Host
Virus
Humans
Oro/Nasopharynx
Droplets
Oro/Nasopharynx
Humans
» Notice the circle (i.e. Original Host to New Host)
» To prevent the spread of disease, the circle must be broken
• Source of infectious agent = Reservoir Host
– Human Reservoirs
» may be overt, subclinical, or carriers (covert)
– Animal Reservoirs
– Zoonosis = when an disease is transmissible from animals to
humans
» exp = rabies, Lyme disease
» usually these diseases not transmissible from human to human
• Means of transmission from reservoir host to susceptible host
– Direct Transmission i.e. person to person
– Indirect Transmission
• there is an intermediate involved
– Animal Intermediates
» non-human animals are called Vectors
– Inanimate Intermediates (from the environment)
» these called Fomites
» exp = contaminated food, bedding, soil, etc.
Pathogens; Etiologic Agents that cause Infections
• Viruses
– intracellular parasites
– chemotherapy difficult
– more resistant than bacteria
to chemical disinfectants
– heat = OK to kill them
• Rickettsiae
– obligate intracellular
parasites ( i.e. cant live
outside the host)
• Thus, Tick borne
– small Gram (-) bacteria
• Fungi
– 2 types:
• yeast = unicellular
• mold = multicellular
• Bacteria
– can live outside the cell
– some can form Spores under
adverse conditions
• hard to kill
– 3 basic shapes
– Cocci
– Bacilli
– Spirilla
• Parasites
– protozoa = unicellular organisms
– metazoa = multicellular
– ectoparasites = arthropods,etc.
– exp = mites, ticks, lice,
fleas, wasps, bees,
mosquitoes, spiders
Body’s Defense Mechanism
• Non-specific Mechanisms
1. Barriers
a. Physical = Skin, Tears, & Mucus
b. Chemical = Stomach Acid, Sweat’s acidic pH
2. Inflammatory Response
– Tissue Injury Produces:
1. Histamine
= vasodilitation
2. Prostaglandins
= porous capillary walls
= directly stimulates nerves
= directly causes fever
– Key symptoms
» Local: edema, redness, heat, pain
» Systemic : fever
Body’s Defense Mechanism
• Specific mechanisms involve “antigen- antibody” reaction
• Antigen = the invader
• Antibody = the defense
• Specific Mechanisms
– Natural Acquired Immunity
– Active = species specific inheritance or getting the disease
– Passive = get antibodies from mother (lasts 6-8 months)
– Artificial Acquired Immunity
– Active = from Vaccines
– Passive = giving the antibodies
» Obtained from Gamma Globulin from an infected organism
Passive gives you the Antibody ; Active gives you the Antigen
Standard Precautions
• Universal Precautions
• Issued by CDC – 1985
• Purpose: to reduce risk of getting/giving infectious disease
• Handle all blood & body fluids as contaminated
• OSHA blood pathogen standard
• Became law in 1992
• This was added to the standard precautions issued by CDC in 1996
• Standard Precautions
• Issued by CDC – 1996
• Purpose: to protect people(health team, patient, visitors) from
communicable diseases
• Essentially combines universal precautions with “body substance isolation” techniques
using “personal protective equipment” (PPE)
• Transmission-based Precautions
• Issued by CDC – 1996
• Purpose: to be used when caring for patients with specific diseases
• Deals with airborne, droplet, & contact disease transmission
Standard Precautions
•
Deals with:
1. Medical asepsis
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2.
Use of PPE
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3.
Wash hands
Sanitize & disinfect equipment
Gloves
Mask
Gown
Deal with waste & disposal (see follow-up slide)
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OSHA --- deals with waste in facility
EPA --- deals with waste outside facility
4.
Sterilize instruments
5.
Spills (see follow-up slide)
WASTES
1. Medical
2. Contaminated
3. Non-Medical
• Medical ( Infectious) Waste
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1. laboratory waste = chemicals, detergents, containers
2. pathology specimens = human tissue, blood, excrement, secretions
3. surgical specimens = human parts removed at surgery / autopsy
4. sharps = any device having rigid areas capable of cutting / piercing
5. liquid body waste = stool, excretions, secretions
6. contaminated waste –things that have been used on body (dressings)
• Non-Medical Waste
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- non-patient care waste
- kitchen waste
SPILLS
• should be promptly cleaned up
• clean up = * gloved employee
* paper towels
* infectious waste container
• after clean up :
– disinfect area with bleach solution
• household bleach = 5.25% sodium hypochlorite
• bleach solution = 1:10 dilution
Handling of Equipment & Supplies
• Sharps (includes Needles)
– place used disposable needles, syringes, & scalpel blades in rigid
disposable containers (red hard plastic containers)
– keep needle containers (i.e.. Sharps container) upright and at a level where
the top opening can be seen
– NEVER remove a needle from a syringe ; put whole apparatus
immediately into sharps container
– NEVER cap or attempt to cap the needle (N.B.. ”one hand technique”)
• Lab Specimens
– use containers that prevent leakage
– use gloves when handling specimens
• Broken Glasswear
– NEVER pick up directly with the hands
• Reusable equipment
– Should be placed ASAP in EPA-approved detergent
– Should be cleaned in a specific area used only for decontamination
Transmission –based Precautions
• Purpose: to be used when caring for patients with specific
diseases
– Used to reduce risk of disease transmission via air, droplets, & contact
– Used as an addition to standard precautions
• Airborne precautions
• Respiratory protection
– If have TB use special filter mask
• Patient transport
– Put mask on patient
• Droplet precautions
• Same as airborne
• Keep 3 feet away from patient
• Contact precautions
• Use PPE
• Wash hands after glove removal with antimicrobial soap
Surgical Asepsis
Principles & Practice of Surgical Asepsis
Key: Surgical asepsis = sterilization
• Know what is sterile & what is not sterile
• Open sterile packs with edges of wrapper directed away from body
» avoids reaching over a sterile field
» avoids things touching your body
• Avoid reaching across a sterile field
• Hold objects and hands ABOVE waist level at all times
• Keep sterile area away from windows & drafts
• Remedy a contaminated situation immediately
• Questions
– What do you do if during a sterile procedure your glove is punctured by a needle?
– How do you open a sterile package?
– If you open a sterile pack & don’t use it, what do you do?
Surgical Asepsis
Surgical Asepsis and Sterilization
•Steam Sterilization (Autoclave)
•Dry Heat Sterilization
•Gas Sterilization
•Chemical Sterilization
• Autoclave ; Steam Under Pressure
– 250o F - for- 15 - 30 minutes
– minimum time = 12 minutes
» variables : Increase in Pressure Increases Temp
Increase in Altitude Decreases Pressure
– Steam exists in 3 forms:
• Steam for sterilization needs adequate water vapor
– 1. Saturated Steam = as much water as possible (This is Best)
– 2. Wet Steam = steam gets too much water from condensate
from steam-carrying pipes (Things get wet)
– 3. Superheated Steam = “good” steam, i.e.. Saturated steam,
gets overheated & get “dry” steam
which is not good for sterilizing
• Autoclave (cont)
– Technique
– Avoid Air Pockets
» Steam is lighter than air, thus as steam forms it forces the dry
air down and out
» Thus, place hollow things, cups, & containers on their side
– Don’t Overload
» Air must circulate between items freely
» leave 1 to 3 inches between things
– If have two shelves, one on top of the other, place soft things on
top and hard things on the bottom
» this prevents water condensate from dripping down on , for
example, linen packs
– When cycle finished, open door slightly for 15 minutes to allow
contents to dry before removing them
• Dry Heat Sterilization
– resembles putting things in an oven
– need 320oF for 1 hour
– good for instruments that corrode
• Gas Sterilization
– uses gas----- ethylene oxide
– useful for heat & moisture sensitive items
» Rubber goods
» lens
– needs 140oF for 6 hours & time for aeration (takes overnight)
• Chemical Sterilization
– least effective
– time varies with chemical used
– Cidex = most common chemical solution used
Wrapping for Sterilization Techniques
• 1. Prepare Materials
• this involves sanitizing (washing & cleaning)
• 2. Inspect Materials
• make sure things are in proper working order
• 3. Wrap Materials
– these materials allow steam or chemical vapors to penetrate,
but do not allow airborne or surface contaminants to enter
• muslin = cotton fabric----------------Shelf Life = 1 month
• special paper ------------------------- Shelf Life = 1 month
• special disposable envelopes ------ Shelf Life = 3 months
– Technique for paper & muslin :
» Diamond; Bottom; Right Side; Left Side ; Fold Up