Infection ControlInfection Control&&

MicroorganismsMicroorganisms

Medical & Surgical AsepsisMedical & Surgical Asepsis

Universal PrecautionsUniversal 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

AsepsisAbsence of Pathogens

• Mainstay of medical asepsis = handwashing– 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 control1. Sanitation ----- soap & water wash2. Disinfection --- use of chemicals to destroy most (not all)

pathogens » Antiseptics – used on people (exp: alcohol, betadine)

*** HANDWASHING» Disinfectants – used on objects (exp: bleach)

3. Sterilization -- destroys all microorganisms• Use autoclave ---- steam under pressure

Handwashing

• 2 types: Medical handwashing & Surgical handwashing

• Key points for medical handwashing• Turn on faucets with dry towel• Keep fingers pointing down• Clean nails• Turn off faucets with dry towel

The Factors in an Infectious Process

using example of German Measles» Pathogen Virus

» Reservoir/Source(Original Host) Humans

» “Portal of Exit” from Source Oro/Nasopharynx

» Means of Transmission to New Host Droplets

» “Portal of Entry” into New Host Oro/Nasopharynx

» Susceptible Host Humans

» Notice the circle (i.e. Original Host to New Host)» To prevent the spread of disease, the circle must be broken

Chain of Infection•Infectious Agents•Reservoir•Portal of Exit•Means of Transmission•Portal of Entry•Susceptible Host

• 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.

• 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

Pathogens; Etiologic Agents that cause Infections

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

• Deals with:1. Medical asepsis

• Wash hands• Sanitize & disinfect equipment

2. Use of PPE• Gloves• Mask• Gown

3. Deal with waste & disposal (see follow-up slide)• OSHA --- deals with waste in facility• EPA --- deals with waste outside facility

4. Sterilize instruments

5. Spills (see follow-up slide)

Standard Precautions

WASTES 1. Medical 2. Contaminated 3. Non-Medical

• Medical ( Infectious) Waste– 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– - non-patient care waste– - kitchen waste

SPILLSSPILLS

• 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 AsepsisSurgical AsepsisPrinciples & 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 AsepsisSurgical 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 TechniquesWrapping 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