infection control. definition of terms asepsis –absence of disease-producing microorganisms...

Infection Control

Definition of Terms

• Asepsis

– Absence of disease-producing microorganisms

• Sterility

– Complete absence of all microorganisms

Definition of Terms

• Pathogen

– Microorganism capable of causing disease in humans

• Hospital acquired infections (nosocomial infections)

– Infection acquired during the course of hospitalization.

– Accounts for 2 million infections, 4.5 billion dollars and

90,000 deaths annually in the U.S.

Definition of Terms

• Cross contamination

– Transmission of microorganisms between places or persons

• Contamination

– Presence of a microorganism in an otherwise sterile

environment

Definition of Terms

• Virulence

– Heightened ability of an organism to produce infection in its

• Exotoxin

– Poisonous substance produced primarily by gram positive

bacteria and secreted into surrounding media; some are

extremely lethal

Definition of Terms

• Endotoxin

– Poisonous substance produced by gram negative bacteria

and released when the bacterial cell is destroyed

• Vector

– Insect, animal, or other carrier that transfers an infecting

agent from one host to another

Etiology

• Primary source of HAI’s are humans (visitors, personnel, other patients)

• There are 3 major routes for transmission of human sources of infection in the hospital:– Direct and indirect contact

• Direct contact - Person to person (infection from the host to another)

• Indirect contact – Transfer of organism thru a contaminated object or intermediate person (unwashed hands passing a pathogen picked up from one patient and passing it on to another patient)

• The most frequent route of pathogen transmission in the hospital setting is via indirect contact

Etiology

• There are 3 major routes for transmission of human sources of infection in the hospital (cont):– Respiratory droplets

• Coughing, sneezing, talking• Use mask within 6 feet of patient or when entering room

– Airborne droplet nuclei (respirable particles < 5 micrometers)• Remains suspended in air for long periods• TB, Varicella, Variola, Rubeola, SARS• Requires negative pressure room• Requires N-95 fit tested mask

Infection Prophylaxis

• The techniques used by most hospitals to reduce host susceptibility to infection focus mainly on the employee. These include:– Immunizations and chemoprophylaxis– OSHA mandates that employers provide Hepatitis B

vaccinations– Postexposure chemoprophylaxis is recommended after

exposure to B. pertussis, N. meningitides, B. anthracis, Influenza virus, HIV, and group A streptococci

– Hand washing for at least 15 seconds is still the single most important procedure for reducing hospital acquired infections

– Multi-dose vials of saline, water, and medications should be time/dated when opened and discarded if contaminated and/or not used within 24 hrs.

– Most disposable respiratory equipment should be discarded and replaced every 48 hrs., This includes ventilator circuits large and small volume nebulizers and humidifiers.

– Once a piece of equipment has been used and becomes contaminated, that piece of equipment must be thrown out if disposable, cleaned or sterilized

– Gloves are not 100% pathogen proof.– Hand washing between patients is not the same hand

washing you would use going into a NICU or OR

Biohazardous Waste

• Defined as:– Laboratory waste including specimen cultures, live and

attenuated vaccines, surgery specimens and blood

– Waste containing discarded materials/equipment contaminated with exudate or secretions from patients required to be isolated

– Contaminated sharps including needles, blades, broken glass, or any items capable of cutting or piercing

– Any disposable item such as dressings, gloves, gowns etc., visibly soiled with recognizable human blood or body fluids

Biohazardous Waste

• What it is not:– Unless it contains fluid blood, the following are NOT

considered biohazardous waste pursuant to the California Department of Health • Urine• Feces• Saliva/sputum• Nasal secretions• Sweat • Tears• Vomit• Always refer to your clinical sites policy and procedures

• Disposal of biohazardous medical waste– All glass, sharps, guide wires, stylets must be placed in an

approved sharps container.– Dry wound dressings, dry gloves, diapers and other forms

of contaminated equipment not saturated or dripping with blood or other body fluids may be placed in regular trash

– Wet, dripping or fully saturated dressings, IV tubing and their empty bags, ventilator circuits, HME’s, and other pieces of equipment with blood, liquid secretions, liquid mucous, must be placed in a red biohazard bag.

– Any equipment coming out of an isolation room including PPE must be placed in a red biohazard bag or sharps container

Yellow sharpscontainers and bags are for chemotherapy waste

Biohazard bag

Sharps container

• The 5 key recommended components of an infection control program in the hospital setting are:– Surveillance– Investigation– Prevention– Control– Reporting

Classification of Organisms

• Eukaryotic

– Types

• Protozoa

• Fungi

• Slime molds

• Algae (except blue-green)

• Prokaryotic

– Types

• Bacteria

• Rickettsiae

• Mycoplasmas

• Blue-green algae

• Viruses

– Simple nucleic acid chain

(DNA or RNA)

– Has a protein coat

– Some debate as to whether

they can be classified as

living organisms

Bacterial Environments

• Bacterial requirements:– Growth medium

– Atmospheric gas

– Temperature

– pH range

– Moisture

– Light

Requirements For Bacterial Growth

• Growth medium

– Varies by bacteria from simple to complex nutrients

– Simple nutrients

• Water, carbon, nitrogen, oxygen, calcium, potassium,

– Complex nutrients

• Sugars, amino acids, blood products

• Atmospheric gas requirements

– Obligate aerobes

• Require oxygen for reproduction

– Obligate anaerobes

• Only reproduce in an oxygen free environment

– Aero tolerant anaerobes

• Unaffected by exposure to oxygen

• Atmospheric gas requirements (cont)

– Facultative anaerobes

• Reproduce under aerobic or anaerobic conditions

– Microaerophilic anaerobes

• Reproduce best at low oxygen levels; high oxygen

levels are inhibitory

• Atmospheric gas requirements (cont)

– Chemolithotrophic and photolithotrophic bacteria use

carbon dioxide as principal source of carbon

• Temperature requirements

– Psychrophilic

• —5° C to 30° C (optimum range 10° C - 20° C)

– Mesophilic (pathogenic)

• 10° C to 45° C (optimum range 20° C - 40° C)

– Thermophilic

• 25° C to 80° C (optimum range 50° C to 60° C)

• Hydrogen ion (pH) requirements

o Pathogens 7.2 to 7.6 (optimum range)

o Acidophiles 6.5 to 7.0

o Neutrophiles 7.5 to 8.0

o Alkalophiles 8.4 to 9.0

• Moisture

– Essential for all bacterial growth

• Light

– Most bacteria prefer darkness

– Ultraviolet and blue light are destructive to bacteria

Bacterial Shapes

• Spherical – coccus

• Rod – bacillus

• Spiral – spirillum, spirochete

• Comma-shaped – vibrio

• Spindle-shaped – fusiform

Staining

• Gram staining of bacteria

• Purpose:

– To separate bacteria into two general categories: gram

positive and gram negative bacteria

– The technique is based on the fact that the Gram positive

cell wall has a stronger attraction for crystal violet when

Gram's iodine is applied than does the Gram negative cell

Staining

• Gram's iodine is able to form a complex with the crystal

violet that is attached more tightly to the Gram-positive

cell wall than to the Gram-negative cell wall. This

complex can easily be washed away from the Gram-

negative cell wall with ethyl alcohol. Gram-positive

bacteria, however, are able to retain the crystal violet

and therefore will remain purple after DECOLORIZING

with alcohol.

Gram Stain Bacteria

• Gram positive

organisms stain

blue or violet

• Gram negative

organisms stain

red or pink

Acid-Fast Stain

• Used to identify

bacteria of the genus

Mycobacterium

• Acid-fast bacteria

appear red against a

blue background

Acid-fastness is a physical property of some bacteria referring to

their resistance to decolorization by acids during staining procedures

Acid-Fast Stain

• The primary stain used in acid-fast staining,

carbolfuchsin, is lipid-soluble and contains phenol,

which helps the stain penetrate the cell wall. This

is further assisted by the addition of heat. The

smear is then rinsed with a very strong decolorizer,

which strips the stain from all non-acid-fast cells

but does not permeate the cell wall of acid-fast

organisms. The decolorized non-acid-fast cells then

take up the counterstain.

Common Gram Positive Bacteria

• Bacillus anthracis

– Rod-shaped, arranged in chains, spore forming

– Secretes endotoxin

– Causes skin infections, septicemia, enteritis, meningitis,

anthrax, and pneumonia (wool-sorter’s disease)

• Clostridium botulinum

– Rod-shaped pairs, spore forming

– Causes botulism

• Clostridium perfringens

– Rod-shaped in pairs, spore forming

– Causes gas gangrene

• Clostridium tetani

– Rod-shaped in pairs, spore forming

– Causes tetanus

• Streptococcus pneumoniae

– Coccus, arranged in chains, may produce capsules

– Aerobic

– Causes lobar pneumonia; may cause empyema,

septicemia, meningitis, and peritonitis

• Staphylococcus aureus

– Coccus arranged in irregular, grapelike clusters

– Aerobic, facultative anaerobe

– Produces exotoxin and endotoxin

– Causes pneumonia, empyema, and wound infection

Common Gram Negative Bacteria

• Pseudomonas aeruginosa

– Rod-shaped, found as a single organism

– Responsible for up to 10% of all hospital acquired infections

– Causes pneumonia with characteristic green odoriferous

sputum; also causes wound infection, urinary tract infection,

empyema, meningitis, and septicemia

• Serratia marcescens

– Rod-shaped

– Aerobic

– Causes empyema, septicemia, wound infections;

responsible for some hospital epidemic

• Escherichia coli

– Aerobic

– Responsible for 45% of all nosocomial infections

– Causes necrotizing pneumonia, septicemia, endocarditis,

meningitis, wound infections, and urinary tract infections

• Klebsiella pneumoniae

– Short rod found as a single organism, produces capsules

– Causes necrotizing pneumonia with characteristic “red

currant jelly” sputum; also causes lung abscesses,

endocarditis, and septicemia

• Hemophilus influenzae

– Minute rod found as a single organism

– Common cause of epiglottitis in children; also causes

meningitis, laryngitis, croup, and sub acute bacterial

endocarditis

• Salmonella typhi

– Produces exotoxin

– Resistant to freezing

– Transmitted through contaminated water and, less

frequently, food

• Salmonella enteritidis

– Rod-shaped

– Found in animals, particularly shellfish, swine, and fowl

• Salmonella enteritidis

– Transmitted orally via contaminated milk, turtles, eggs,

undercooked chicken, fish, clams, and pork

– Causes enteritis that may progress to meningitis,

encephalitis, or nephritis

• Bordetella pertussis

– Minute, non-motile coccobacillus

– Causes whooping cough

• Neisseria meningitides

– Coccus found as diplococci

– Aerobic

– Causes meningococcal meningitis, bacteremia, and

pneumonia

• Proteus mirabilis and Proteus vulgaris

– Causes chronic urinary tract infections, pneumonia,

gastroenteritis, and bacteremia

Common Mycobacterium

• General characteristics

– Acid-fast, gram positive, aerobic rods

– Virulent strains found in cords – two chains in

side-by-side parallel arrangement

• Mycobacterium tuberculosis

– Very slow growing; requires three to six weeks for culture

– Causes pulmonary tuberculosis, spinal tuberculosis, and

miliary tuberculosis

– Transmitted through inhalation of droplet nuclei

– Causes necrotizing lesion with caseating center

• Mycobacterium leprae

– Transmission is intimate contact

– Causes leprosy

• Mycobacterium avium complex (MAC) and

Mycobacterium avium intracellulare (MAI)

– Non-tuberculous forming mycobacterium

– Does not require same level of precautions

– Causes chronic pulmonary infections

Common Fungi

• Characteristics

– Primarily work to decompose dead and decaying matter

(saprophytes)

– Some parasitic types derive food from living plants or animals

– May cause pulmonary infection or pneumonia through

inhalation

– Yeast: single cell forms

Common Fungi

• Pneumocystis carinii

– Normally not pathogenic

– Dormant in most individuals

– Mode of transmission is inhalation

Common Fungi

• Pneumocystis Carinii

– Common infection in immunosuppressed hosts; common

in HIV patients

– Causes diffuse panlobular pneumonia with abrupt onset,

fever, tachypnea, hypoxia, cyanosis, and possible

asphyxia in the acute stage

Isolation Procedures

Types of PPE Used in Healthcare Settings

• Gloves – protect hands

• Gowns/aprons – protect skin and/or clothing • Masks and respirators– protect mouth/nose

– Respirators – protect respiratory tract from airborne infectious agents

• Goggles – protect eyes

• Face shields – protect face, mouth, nose, and eyes

• Handwashing

– The single most important act to prevent spread of infection

– Wash hands after touching blood, body fluids, secretions,

excretions, or contaminated items, even if wearing gloves

– Wash hands between patient contacts or between

procedures on the same patient

• Standard precautions

– Hand washing

– Gloves: clean, non-sterile gloves when touching blood,

body fluids, secretions, mucus membranes, and

contaminated equipment

• Standard precautions

– Gowns: clean, non-sterile gowns to protect against

activities that may generate splashes or spray of blood,

body fluids, secretions, or excretions

– Mask and eye protection: if danger of splashes or spray

• Contact precautions

– Standard precautions apply

– Required in treatment of patients where transmission of

pathogens occurs from body-to-body contact

– Gloves required

– Gowns for direct contact with patient

– Private room

– Equipment dedicated to only one patient

• Droplet precautions

– Surgical mask when within six feet of patient

– Private room

– Door may remain open

• Airborne precautions

– N95 mask is required unless isolation is for measles or

chicken pox and the caregiver is immune

– Negative-pressure room required

• Reverse Isolation– Protects immunocompromised patients from visitors and

healthcare workers– Standard precautions apply– Gowns, gloves, surgical masks required

How to Don a Gown

Select appropriate type and size

Opening is in the back

Secure at neck and waist

If gown is too small, use two gowns– Gown #1 ties in front– Gown #2 ties in back

How to Don a Mask

Place over nose, mouth and chin

Fit flexible nose piece over nose bridge

Secure on head with ties or elastic

Adjust to fit

How to Don a Particulate Respirator

Select a fit tested respirator

Place over nose, mouth and chin

Fit flexible nose piece over nose bridge

Secure on head with elastic

Adjust to fit

Perform a fit check – – Inhale – respirator should collapse– Exhale – check for leakage around face

How to Don Eye and Face Protection

Position goggles over eyes and secure to the head using the ear pieces or headband

Position face shield over face and secure on brow with headband

Adjust to fit comfortably

How to Don Gloves

Don gloves last

Select correct type and size

Insert hands into gloves

Extend gloves over isolation gown cuffs

How to Safely Use PPE

Keep gloved hands away from face

Avoid touching or adjusting other PPE

Remove gloves if they become torn; perform hand hygiene before donning new gloves

Limit surfaces and items touched

Where to Remove PPE

At doorway, before leaving patient room or in anteroom*

Remove respirator outside room, after door has been closed*

* Ensure that hand hygiene facilities are available at the point needed, e.g., sink or alcohol-based hand rub

How to Remove Gloves (1)

Grasp outside edge near wrist

Peel away from hand, turning glove inside-out

Hold in opposite gloved hand

How to Remove Gloves (2)

Slide ungloved finger under the wrist of the remaining glove

Peel off from inside, creating a bag for both gloves

Discard

Remove Goggles or Face Shield

Grasp ear or head pieces with ungloved hands

Lift away from face

Place in designated receptacle for reprocessing or disposal

Removing Isolation Gown

Unfasten ties

Peel gown away from neck and shoulder

Turn contaminated outside toward the inside

Fold or roll into a bundle

Discard

Hand Hygiene

Perform hand hygiene immediately after removing PPE.– If hands become visibly contaminated during PPE

removal, wash hands before continuing to remove PPE

Wash hands with soap and water or use an alcohol-based hand rub

* Ensure that hand hygiene facilities are available at the point needed, e.g., sink or alcohol-based hand rub

PPE Use in Healthcare Settings:When to Use PPE

• Thus far we have discussed the various types of PPE, considered various factors that go into selecting appropriate PPE, and described how to don, use, and remove PPE safely. This last segment of this presentation will discuss WHEN to use which PPE.

Standard and Expanded Isolation Precautions

• Decisions regarding when and which type of PPE should be worn are determined by CDC recommendations for Standard Precautions and Expanded Isolation Precautions.

Standard Precautions

Previously called Universal Precautions

Assumes blood and body fluid of ANY patient could be infectious

Recommends PPE and other infection control practices to prevent transmission in any healthcare setting

Decisions about PPE use determined by type of clinical interaction with patient

PPE for Standard Precautions (1)

Gloves – Use when touching blood, body fluids, secretions, excretions, contaminated items; for touching mucus membranes and nonintact skin

Gowns – Use during procedures and patient care activities when contact of clothing/ exposed skin with blood/body fluids, secretions, or excretions is anticipated

PPE for Standard Precautions (2)

Mask and goggles or a face shield – Use during patient care activities likely to generate splashes or sprays of blood, body fluids, secretions, or excretions

What Type of PPE Would You Wear?

Giving a bed bath?Suctioning oral

secretions?Transporting a patient in a

wheel chair?Responding to an

emergency where blood is spurting?

Drawing blood from a vein?

Cleaning an incontinent patient with diarrhea?

Irrigating a wound?Taking vital signs?

What Type of PPE Would You Wear?

Giving a bed bath?Gown, gloves

Suctioning oral secretions?Gloves and mask/goggles or a

face shield – sometimes gown

Transporting a patient in a wheel chair?

Generally none required

Responding to an emergency where blood is spurting?

Gloves, fluid-resistant gown, mask/goggles or a face shield

Drawing blood from a vein?Gloves

Cleaning an incontinent patient with diarrhea?

Gloves with or without gown

Irrigating a wound?Gloves, gown, mask/goggles

or a face shield

Taking vital signs?– Gloves

Disinfection and Sterilization

• Definitions

– Cleaning: the removal of all foreign matter such as

sputum, blood, dirt, or organic matter that may provide

an environment for bacterial growth

– Disinfection: a process to eliminate vegetative, pathogenic

microorganisms on inanimate objects; differs from

sterilization by lack of sporicidal activity

– Sterilization: complete destruction or inactivation of all

forms of microorganisms

• Cleaning

– Must be done in an area with separate “dirty” and “clean”

sections

– Equipment to be cleaned must be completely disassembled

• Cleaning

– Soap, detergent, or enzymatic cleaners must be used

– If the object, such as electrical equipment, cannot get wet,

then the surface of the device should be cleaned with

70% isopropyl alcohol

Disinfection

• Disinfection describes a process that destroys the vegetative form of all pathogenic organisms on an inanimate object except for spores

Disinfection

• Alcohol

– Ethyl alcohol and isopropyl alcohol used in healthcare

setting

– Recommended concentration: 70%

– Inactivated by protein

– Can damage rubber, plastic, and the shellac mounting of

instruments with lenses

Disinfection

• Quaternary ammonium compounds

– Surface acting agents containing ammonium ion that leads to

lysis of the cell walls

– Best with an alkaline pH

– Gram positive bacteria are most susceptible

– Ineffective against tuberculosis bacilli, spores, viruses, Hepatitis B,

and some fungi

– Can be stored and reused for up to two weeks if undiluted

Disinfection

• Acetic acid (vinegar solution)

– Inhibits growth of bacteria and fungi

– 1.25% solution appears to have sufficient effectiveness

(1 part vinegar to three parts water)

– Effectiveness reduced when reused

– Used extensively in the home care setting by caregivers

Disinfection

• Phenols (Lysol)

– Bactericidal, fungicidal, and tuberculocidal

– Retain activity in the presence of organic matter and are

active for a significant time after application

– Easily absorbed by porous material and may irritate skin

through contact

Disinfection

• Iodophors (iodine solution, betadine)

– Bactericidal, virucidal, and tuberculocidal

– Can be used on skin

– Water soluble, non-staining

Sterilization

• Glutaraldehydes

– Widely used in disinfection/sterilization of non-critical items

– All surfaces must be in contact with solution for it to be

effective

– Generally bactericidal, tuberculocidal, fungicidal, and

virucidal when object is in contact with the solution for ten

to thirty minutes; sporicidal if immersed for ten hours

– Must be rinsed thoroughly after use to avoid skin irritation

Sterilization

• Sodium hypochlorite (household bleach)

– Exposure to 1:50 dilution for ten minutes sufficient to kill

vegetative bacteria, bacterial spores, and tuberculosis

organisms

– CDC recommends 1:10 solution for disinfecting blood spills

– Do not allow mixing with any acid solution; toxic fumes

result

Sterilization

• Autoclaving

– Use of steam under pressure for a given duration of time –

most common settings are 121° C at 15 lb/sq. inch for 15

minutes

– Equipment is cleaned and packaged prior to sterilization

– Most common, efficient, and easiest sterilization method

Sterilization

• Autoclaving

– Variables for effectiveness

• Temperature

• Pressure

• Concentration of steam

• Holding time – minimum time necessary to kill spores at

a specific pressure

Sterilization

• Autoclaving

– Heat sensitive indicators demonstrate equipment has been

exposed to conditions necessary for sterilization – they do

not indicate sterility

Before After

Sterilization

• Ethylene Oxide ((CH2)2O)

– Gas at room temperature, but liquefies readily under

pressure

– Has distinct, almost sweet odor

– Causes irritation to tissue, especially mucus membranes

– Flammable and explosive

Sterilization

– Variables for effectiveness

• Gas concentration

• Humidity

• Temperature

• Time of exposure

Sterilization

– Packaging material must be permeable to humidity and ETO

– Biological indicator necessary to ensure sterilization

– Aeration time required – 24 hours in a well ventilated area

– Toxicity to humans includes mutagenicity and carcinogenicity

EO BurnEO

Explosion

Respiratory Therapy Equipment

• Large volume nebulizers

– Most common source of equipment related patient infections

– Always use distilled water

– When refilling, empty remaining fluid and then refill

– Drain tubing away from the patient

– Change and sterilize large volume nebulizers every twenty-four hoursDepends on facility, once a week

• Small volume nebulizers

– Daily between treatments on the same patient, rinse with sterile water, and air dry

– Replace every 72 hrs

– Use disposable or sterilized units between patients

– Use single use medication vials whenever possible

• Ventilator circuits

– Infections uncommon due to use of high efficiency

particulate air/aerosol filters

– Change every 30 days

– Sterilize circuits, if non-disposable

• Ventilator circuits

– Place bacterial filters

proximally to the humidifier

– Use sterile water to fill

humidifiers

– Change heat-moisture

exchangers (HMEs)

according to manufacturer’s

specifications

• Bag-valve-mask devices

– Must be sterilized between patients if non disposable, BUT

most are disposible

– Should be cleaned and exterior disinfected daily when in

use with one patient

• Suction systems

– Use a fresh, sterile single-use catheter on each patient

– Canister and tubing must be changed between patients

• Oxygen therapy equipment

– Minimal risk associated with oxygen therapy equipment

– If using humidifier, it must be changed between patients

• Pulmonary function equipment

– External tubing must be exchanged and sterilized between

patients

– Inner parts of equipment pose little risk of cross-

contamination

• Use disposable equipment whenever possible

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