Textbook for Nursing Assistants
Chapter 10: Communicable Disease and
Infection Control
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1
What are Communicable Diseases?
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Communicable Diseases
• Communicable diseases are diseases that can be spread
from one person to another
– You must learn to protect yourself, your family
members, and your patients or residents from
catching a communicable disease
– You must also learn about the causes of
communicable disease, and the ways communicable
diseases are spread from one person to another
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3
What is a Microbe?
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What is a Microbe?
• A microbe, also called a microorganism, is a living thing
that cannot be seen with the naked eye
• Most microbes cause no harm and are actually essential
for healthy living: called normal (resident) flora
• Some microbes, however, can cause illness and are
known as pathogens
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Opportunistic Microbes
• Sometimes microbes can be considered normal flora in
one part of the body and pathogens in another
• These types of microbes are called opportunistic
microbes
• For example:
– Escherichia coli. When E. coli finds its way out of the
intestine and into another part of the body where it is
not normal flora, such as the bladder, it can cause an
infection
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Classification of Microbes
MICROBES
Bacteria
Viruses
Fungi
Parasites
Helminths
Protozoa
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Microbes: Bacteria
• Bacteria cause many of the infections you will encounter in the
health care setting
• The ability of bacteria to adapt to all sorts of environments is
proof of this life form’s ability to survive
• Scientists classify and name bacteria in many different ways
– By their shape
– By the way they arrange themselves in a colony
– By the way they stain (i.e., how they react to the dye
scientists use to make microbes more visible under a
microscope)
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Microbes – Bacteria – Classification
Classification on the basis of shape
Round bacteria are
called cocci
Rod-shaped
bacteria are called
bacilli
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Spiral-shaped or
curved bacteria are
called spirilla
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Microbes – Bacteria – Classification
(cont.)
By the way they arrange themselves in a
colony
Pairs of bacteria
(indicated by the
prefix diplo-)
Chains of bacteria
(indicated by the
prefix strepto-)
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Grape-like clusters of
bacteria (indicated by
the prefix staphylo-)
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Microbes – Bacteria – Classification
(cont.)
By their basic requirements for survival
Aerobic: need
oxygen to live
Anaerobic: die if
oxygen is present
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Microbes – Bacteria – Endospores
– Some types of bacteria can surround themselves with
a hard shell, called an endospore, and enter a state
of inactivity
– Once the inactive bacterium’s best growing
conditions become available, the bacterium will
become active again
– Because of their protective endospores, these types
of bacteria are very difficult to kill using the standard
techniques
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Microbes – Bacteria – Illnesses
• Illnesses caused by bacteria:
– Tetanus (lockjaw)
– Botulism (food poisoning)
– Strep throat
– Some bladder infections
– Some skin infections
– Rocky Mountain spotted fever
– Typhus
– Some types of pneumonia
– Some infections of the reproductive and urinary systems
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Microbes – Viruses
• Viruses are the smallest of all microbes
• They can only be seen using a special kind of microscope,
called an electron microscope
• Many illnesses are caused by viruses, such as:
– The common cold
– Fever blisters
– Chicken pox
– Hepatitis
– AIDS
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Microbes – Fungi
• Fungi are a group of plant-like organisms that scientists
have classified together because of certain
characteristics, including the make-up of their cell walls
• Examples of illnesses caused by fungi are
– Ringworm
– Athlete’s foot
– Thrush
– Candidiasis
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Microbes – Parasites
• Parasites live in or on a host, such as a plant or animal,
and use that host for food and protection
• Examples of illnesses caused by parasites are
– Scabies (mites)
– Pediculosis (lice)
• Other types of parasites are
– Helminths (pinworms, tapeworms, roundworms)
– Protozoa (malaria, amebic dysentery)
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Question
• Although there are many microbes found throughout
nature, only about one-half will cause disease in humans.
A. True
B. False
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Answer
B. False
• Most microbes cause no harm and are actually essential
for healthy living.
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Defenses Against
Communicable Disease
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The Immune System
• Many, many microbes share the Earth with us
• If microbes are everywhere, and some of them can make
us sick, then why aren’t we all always sick?
• The answer to this question lies in the body’s immune
system, the wonderful defense system that protects us
from infection
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Nonspecific Defense Mechanisms
• Our main nonspecific defense mechanism is healthy,
intact skin and mucous membranes
• Skin that is without cuts, scrapes, or wounds physically
prevents pathogens from entering the body
• Mucous membranes line all of the organ systems that
come in contact with the outside world (namely, the
respiratory, digestive, urinary, and reproductive systems)
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Nonspecific Defense Mechanisms (cont.)
• If a pathogen gets past the first lines of defense and an
infection results, the body activates a general immune
response
• Fever, inflammation, warmth, and redness at the site of
infection: a normal response to infection
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Specific Defense Mechanisms
• The immune system also has the ability to develop
specialized proteins called antibodies, which help our
bodies to fight off specific microbes
• A person develops antibodies following exposure to the
microbe
• Vaccines expose the body to the microbe, stimulating
antibody production without causing actual illness
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Antibiotics
• An antibiotic is a drug that is able to kill bacteria or make
it difficult for them to reproduce and grow
• Penicillin – first antibiotic, used in WWII
• Multidrug-resistant organisms (MDROs)
– Resistant to one or more classes of antibiotics
• Methicillin-resistant Staphylococcus aureus (MRSA)
• Vancomycin-resistant enterococci (VRE)
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Antibiotics (cont.)
• Some good bacteria are destroyed when using antibiotics
to treat infections, resulting in infections
– Clostridium difficile (C. diff), major cause of health
care–associated diarrhea
• Although antibiotics have given us more options for
treating infectious disease than we had in the past, they
do not work against all pathogens all of the time
• The best policy is clearly to avoid infection in the first
place
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Question
• The best defense against an infection is:
A. medication
B. prevention
C. immune response
D. antibodies
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Answer
B. prevention
• The best policy is to avoid infection in the first place.
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Communicable Disease and the
Chain of Infection
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Chain of Infection
• For a person to get a communicable infection, six key
conditions must be met
• These six key elements are known as the chain of
infection
• Eliminating any one of the six key elements breaks the
chain and prevents the spread of infection
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Chain of Infection (cont.)
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Breaking the Chain of Infection
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Susceptible Host
• Very young
– Immune system not developed
• Very old
– Immune system not as active with aging
• Poor general health
– Body defenses already weak
– Certain medications and treatments affect immune system
• Stress and fatigue
– Lack of rest and emotional stress
• Indwelling medical devices
– Increased risk of infections by providing portal of entry
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Infection Control in the
Health Care Setting
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Health Care–Associated Infections (HAIs)
• Infections people get while a patient or resident
• Health care worker can get while providing care
• Also called nosocomial infections
• Most common method of transmission – the hands!
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Infection Control in the Health Care Setting
• Maintaining cleanliness in health care facilities is
essential, because exposure to pathogens is
increased in these settings
• Most of the people in health care facilities are there
because they are not in good overall health and
their potential to become infected is increased
• All health care facilities follow basic practices that
are designed to decrease the chance that an
infection will be spread from one person to another.
These practices are called infection control
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Methods of Infection Control
• There are four major methods of infection control
– Medical asepsis
– Surgical asepsis
– Barrier methods
– Isolation precautions
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Medical Asepsis
• Medical asepsis involves physically removing or killing
pathogens, and is primarily achieved through processes
involving soap, water, antiseptics, disinfectants, or heat
• There are four techniques that make up the practice of
medical asepsis:
– Sanitization
– Antisepsis
– Disinfection
– Sterilization
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Medical Asepsis: Sanitization
• Sanitization is the word we use to describe practices
associated with basic cleanliness, such as:
– Hand hygiene
– Cleansing of eating utensils and other surfaces
with soap and water
– Providing clean linens and clothing
• Sanitization practices physically remove pathogens,
thereby preventing their spread
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Medical Asepsis: Antisepsis
• Antisepsis takes sanitation one step further, by actually killing
microbes or stopping them from growing
• An antiseptic is a chemical that is capable of killing a pathogen,
or preventing it from growing
• Antiseptics can be used on the skin or other surfaces to kill
pathogens
• Examples of antiseptics:
– Rubbing alcohol
– Iodine
– Alcohol-based hand rub
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Medical Asepsis: Disinfection
• Disinfection involves the use of stronger chemicals to
kill pathogens
• The chemicals used for disinfection are too strong to be
used on the skin
• Disinfectants are used to clean non-living objects that
come in contact with body fluids or substances, such as
bedpans, urinals, and tray tables
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Medical Asepsis: Sterilization
• Sterilization is the most thorough method of killing
microbes
• Sterilization is used on objects that must be
completely free of any microbe, such as surgical
instruments, hypodermic needles, or intravenous
(IV) catheters
• Equipment is sterilized either by placing items in an
autoclave or by soaking the items in chemicals that
destroy all microbes
• Boiling is not an effective method of sterilization
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Medical Asepsis:
Sanitization – Hand Hygiene
• In the health care setting, hand hygiene takes on a
special importance because the chance of picking up a
pathogen and passing it on to someone else is greater
than in normal, everyday life
• Although the specifics of how hand hygiene is performed
vary from setting to setting, one aspect of hand hygiene
always remains the same – it must be performed
thoroughly, properly, and consistently
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Medical Asepsis:
Sanitization – Hand Hygiene (cont.)
• At the minimum, wash your hands:
– When you first arrive at your facility
– When hands are visibly dirty
– When hands are visibly soiled with or in contact with
blood or other body fluids
– When caring for patients or residents who may have
certain infections, such as C. diff
– Before you go on break and before you leave your
shift
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Medical Asepsis:
Sanitization – Hand Hygiene (cont.)
• At the minimum, wash your hands: (cont.)
– Before and after drinking, eating, or smoking
– Before and after inserting contact lenses
– After using the bathroom
– After coughing, sneezing, or blowing your nose
– After touching anything that may be contaminated
with blood or other body fluids or substances
– After handling your hair or applying make-up or lip
gloss
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Hand Hygiene: Using an AlcoholBased Hand Rub
• Alcohol-based hand rubs have several advantages:
– Using an alcohol-based hand rub is quicker than
washing your hands at the sink
– Alcohol-based hand rubs are gentler on the skin than
soap and water
– Alcohol-based hand rubs are used without water, so
they can be used anywhere
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Hand Hygiene: Using an AlcoholBased Hand Rub (cont.)
• It is very simple to use an alcohol-based hand rub
– The label on the product will tell you how much
product to use
– Apply this amount to one of your palms and rub your
hands together, covering your hands and fingers
(front and back) with the product
– Continue rubbing your hands together until your skin
is dry. That's all there is to it!
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46
Question
• The chain of infection can be broken by removing one of
the five elements that must be present for infection to
occur.
A. True
B. False
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Answer
B. False
• There are six elements in the chain of infection:
1. Pathogen
2. Reservoir
3. Portal of exit
4. Method of transmission
5. Portal of entry
6. Susceptible host
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Surgical Asepsis
• Surgical asepsis is used for procedures that involve entering a
person’s body
• Examples of procedures that require surgical asepsis include:
– Surgical procedures
– Injections
– The insertion of intravenous (IV) catheters
– The insertion of urinary catheters
• In most states, performing procedures that require surgical
asepsis is not within a nursing assistant’s scope of practice
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Barrier Methods
• A barrier is an object that physically prevents microbes from
reaching a health care provider’s skin or mucous membranes
• Examples of barriers used in infection control, called personal
protective equipment (PPE), include:
– Disposable gloves
– Gowns
– Masks
– Protective eyewear
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Barrier Methods: Gloves
• Gloves are the most commonly used barrier method
• Gloves are worn in the following situations:
– When there is a possibility that you will come in contact
with body fluids or substances
– When you are performing or assisting with perineal care
– When you have a cut or abrasion on your hands
– When you are shaving a patient or resident
– When you are performing care on a patient or resident
who has an open wound or other break in the skin
– When you are performing oral care
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Barrier Methods: Gloves (cont.)
• To effectively prevent contamination of your hands,
– gloves must be intact
– they must fit properly
• Perform hand hygiene with alcohol-based rub between glove
changes
• The most common error made by people who wear gloves for
barrier protection is becoming too comfortable with the fact
that they are protecting themselves, and forgetting to protect
others! If you are wearing gloves and you touch a surface that
is contaminated, then your gloves become contaminated. If
you then touch something else, that surface becomes
contaminated too.
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Barrier Methods: Gowns
• A gown (fabric or paper) should be used when it is likely
that your uniform will be soiled with body fluids or
substances
• The use of the gown prevents contamination of your
uniform
• Each gown is worn only once
• Any gown, fabric or paper, is considered contaminated if
it becomes wet
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Barrier Methods: Masks
• Masks prevent you from breathing in microbes through your
nose or mouth, and are worn when there is a chance that you
will be exposed to pathogens that are transmitted through the
air or in droplets of saliva
• Surgical masks are most commonly used, but if you are caring
for a person with TB, you may be required to wear a special
high-filtration mask
• All masks are used only once
• Be careful to only handle the ties or straps when removing the
mask
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Barrier Methods: Protective Eyewear
• Goggles, face shields, and other types of protective
eyewear are used to protect your eyes from substances
that may splash
• Goggles fit close and can be worn over glasses
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Applying and Removing PPE
• Sequence to put on:
• Sequence to remove:
– Gown
– Gloves
– Mask
– Eyewear
– Eyewear
– Gown
– Gloves
– Mask
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Isolation (Transmission-Based)
Precautions
• Isolation (transmission-based) precautions are guidelines,
based on a pathogen’s method of transmission, that we follow
to contain the pathogen and limit others’ exposure to it as
much as possible
– Standard precautions are specifically used to protect
health care workers from pathogens that are transmitted
in blood. Since you may not know if a person has this type
of infection, standard precautions are used for everyone
– Isolation precautions include precautions that are used
when a person is known to have a disease that is
transmitted a certain way, for example, via the air, in
droplets, or by direct contact.
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Isolation (Transmission-Based)
Precautions (cont.)
• Airborne precautions are used when caring for people
infected with pathogens that can be transmitted through the
air
• Droplet precautions are used when caring for people with
diseases caused by pathogens that are transmitted by direct
exposure to droplets released from the mouth or nose (for
example, when the person coughs, sneezes, or talks)
• Contact precautions are used when caring for people with
diseases caused by pathogens that are transmitted directly (by
touching the person), or indirectly (by touching fomites)
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Question
• Every nursing assistant should be aware of the potential
of an exposure to a pathogen and be ready to use the
appropriate PPEs to protect him or her from becoming
infected.
A. True
B. False
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Answer
A. True
• It is the responsibility of the nursing assistant to be
aware of the potential of becoming infected and follow
the facility’s policies and use appropriate PPEs when the
situation requires it.
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End of Presentation
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