Health Skills I
Student Lecture Packet
Health Skills I
Unit 101
Infection Control
Objectives
• Identify the nature of microorganisms, how
organisms grow, their transmission, body
defenses of the human host, and related
terminology
Unit 101.1
Microorganisms
• Anton Van
Leeuwenhoek
– first observed
microorganism under
a microscope in 1693
Microorganisms are Everywhere!
• inside and outside our bodies
• in food, air, and water
• some are useful
– fermentation of food
• small percentage cause disease
• organisms can be spread
• healthcare workers need to understand how
to break cycle
Exciting Moments in Microbiology
• Ignatz
Semmelweiss
1860
• reduced the
transmission of
puerperal fever by
handwashing
More Exciting Moments in
Microbiology
• LOUIS PASTEUR
1861
• proposed the
“Germ Theory”
Definitions
• Microorganism
– microscopic living things that individually are
too small to be seen with the naked eye, only
seen under microscope
• example: germs & microbes
• Pathogen
– microorganisms capable of causing disease
Definitions
• Communicable disease
– a pathogenic organism passed from one host
to another
• Host
– one infected with a pathogenic
microorganism
• Susceptible host
– one unable to fight off infection due to low
resistance
Definitions
• Colonized
– presence of microorganisms in or on a
patient, without clinical signs and symptoms
• Infection
– colonization invasion of body tissues by
disease producing pathogenic microorganisms
• Re-infection
– infected a second time by same pathogen
Definitions
• Cross infection
– spread to another person by air currents or
health worker
• Co-infection
– infected with more than one organism
• Secondary infection
– an infection acquired following a primary
illness
• Nosocomial
– infection acquired within a healthcare facility.
Pathogenic Organisms
Virus
• acellular
– cannot survive independently
• parasite
– can only survive on living tissue
– cannot be treated by antibiotics, may use
antiviral drugs
– vaccinations can prevent a number of viral
infections
Pathogenic Organisms
Virus
• Examples:
– polio, influenza,
common cold, HIV,
Hepatitis B, mumps,
herpes
Bacteriophage (virus that infects bacteria)
Pathogenic Organisms
Bacteria
• simple unicellular
organism
– three shapes
• coccus, bacillus,
spirillium
• Clostridium tetani
– bacterium that causes
tetanus
Pathogenic Organisms Bacteria
• can be treated by antibiotics
– examples:
• strep throat, abscesses, gonorrhea, syphilis,
chlamydia, Rocky Mountain Spotted Fever, Lyme
disease
• vaccinations can prevent some bacterial
infections
– example:
• pneumonia
Pathogenic Organisms Fungi
• molds and yeast
– multicellular or unicellular organisms, more
complex than bacteria
Pathogenic Organisms Fungi
• Examples:
– athletes foot,
ringworm, vaginal
yeast infection, thrush
Pilobolus, a fungus
Pathogenic Organisms Protozoa
•
•
•
•
largest single celled organism
relatively few cause disease in humans
many parasites passed by insects
transmitted by food
Pathogenic Organisms Protozoa
• Examples:
– malaria, dysentery,
sleeping sickness
Amoeba, a protozoan
Pathogenic Organisms
Clostridium difficile
(C. difficile)
• C. difficile is:
– a pathogenic species of anaerobic bacteria
causing pseudomembranous colitis and
diarrhea, after receiving antibiotic therapy.
This is frequent cause of nosocomial diarrhea
Definitions
• Anaerobic
– a microorganism that grows and lives in the
complete or almost complete absence of
oxygen
• Pseudomembranous colitis
– diarrhea caused by overuse of antibiotics
transmitted by healthcare workers not
washing hands properly
Pathogenic Organisms
C. difficile
– common hazard of antibiotic use
– most common cause of nosocomial infectious
diarrhea
– may cause bleeding & bowel perforation
– can exist months on environmental surfaces &
flourishes on hands of healthcare workers
– At risk patients:
• chemotherapy, antibiotic therapy &
gastrointestinal procedures
C. difficile
• Standards of care for patient w/ diagnosis of
C. difficile
– good handwashing before & after patient care
procedures
– use of Standard Precaution barriers for Contact
Isolation guidelines (gown, gloves, private room)
– the antibiotic related to the cause of C. difficile
will be discontinued by physician and further care
will begin
Pathogenic Organisms
Vancomycin Resistant Enterococcus
(VRE)
• VRE is:
– a bacteria that normally lives in the digestive
tract that has developed a resistance to the
antibiotic vancomycin and most other
antibiotics
Definitions
• Vancomycin
– antibiotic used to treat strep and staph
infections
• Enterococcus
– any Streptococcus that inhabits the intestinal
tract
Pathogenic Organisms VRE
– caused by overuse of antibiotics
– VRE infections frequently found in:
• urinary tract, at surgical sites, and in the bloodstream
– spreads through:
• direct contact with a VRE infected patient
• direct contact with surfaces & equipment
contaminated with VRE
• hands of a healthcare worker contaminated with VRE
– lives weeks on surfaces
VRE
• At risk patients for VRE:
– immunosuppressed conditions
– history of vancomycin therapy
– indwelling urinary or central venous catheters
– elderly
– abdominal surgery patients
– wounds/burn victims
VRE
• Standards of Care for VRE diagnosed
patients:
– good handwashing before & after care
– use Standard Precaution barriers and contact
Isolation Precautions
– the antibiotic will be discontinued by a
physician with plan for further care
Pathogenic Organisms
(MRSA)
• Methicillin Resistant Staphylococcus
Aureus (MRSA) is:
– bacteria that populates the skin, mucous
membranes and upper respiratory tract, the
intestines and genitourinary tracts that has
become resistant to the antibiotics methicillin
and penicillin
Pathogenic Organisms MRSA
– endemic (expected “normal” incidence)
within community & tertiary hospitals,
skilled-nursing facilities & long-term care
– most frequent sites of this bacteria is the
nares, groin, axilla and gut
– transmitted primarily on the hands of the
healthcare workers
MRSA
• At risk patients for MRSA:
– those on broad-spectrum antibiotics therapy
– immunosuppressed patients
– burn patients
– central venous catheters
– surgical wounds
– prolonged hospital stays
MRSA
• Standard of care for patient w/MRSA
diagnosis:
– topical ointment to nostrils
– if infected, vancomycin
Key Factors
C. difficile, VRE, MRSA
– handwashing & standard precautions
– single room for infected/colonized patients
– use antiseptic cleansers in high risk areas
– daily cleansing of environmental surfaces that
have had direct hand contact
Key Factors
C. difficile, VRE, MRSA
– dedicate equipment for exclusive use for
infected patient(stethoscopes, BP cuffs, etc.)
– keep equipment off bed & bed tables
– provide protective gear to patient when
leaving their room (mask, gown, etc.)
Infection Cycle
• Three Elements
Required:
– source of infecting
microorganisms
– susceptible host
– mode of transmission
source
susceptible
host
mode of
transmission
Infection Cycle
• Source
– may include persons with acute disease
– persons in the incubation period of disease
– persons who are colonized by infectious agent
– persons who are chronic carriers
– can be inanimate objects
Infection Cycle
• Host
– one infected with a pathologic microorganism
– resistance varies
– may develop immunity
– may be an asymptomatic carrier
– may develop clinical disease
Infection Cycle
Transmission
• May be transmitted by more than one
route
• Five main routes:
– contact-direct or indirect
– droplet
– airborne
– common vehicle
– vectorborne
1. Contact Transmission
• *most frequent mode of noscomial infection
• Direct Contact
– skin to skin
• Indirect Contact
– contact with an inanimate object contaminated
by the infected patient
2. Droplet Transmission
– a form of contact
transmission
– droplets are propelled
a short distance (3
feet)
– droplets are deposited
on hosts such as the
mucous membranes
of eye, nose or mouth
droplets are generated by
coughing, sneezing or talking
2. Droplet Transmission
– droplets transmitted during medical
procedures of bronchoscopy or suctioning
that put healthcare workers at risk
– private room ideal
• Can be placed w/other similar conditions 3’ apart
if room availability is an issue
– healthcare worker must wear mask when
caring for a person with droplet isolation
precautions
– Example:
• Influenza
3. Airborne Transmission
– spreads by way of airborne droplets or dust
particles containing infectious agents
(microorganisms) and inhaled by the new host
– spread by air currents
– special handling and ventilation required to
prevent transmission
– requires private room
– Examples
• tuberculosis, rubeola, and varicella (chicken pox),
herpes zosters viruses spread via airborne transmission
3. Airborne Transmission
– spreads by way of airborne droplets or dust
particles containing infectious agents
– spread by air currents
– special handling and ventilation required to
prevent transmission
– requires private room
– Examples
• tuberculosis, rubeola, and varicella (chicken pox),
herpes zosters viruses spread via airborne transmission
4. Common
Vehicle Transmission
– microorganisms transported by contaminated
food, water, medication or equipment
– Examples:
• Hepatitis A, salmonella, Typhoid Fever
5. Vectorborne Transmission
– vectors transport
disease
• mosquitoes, flies, ticks,
rats and other vermin
transmit disease
– Examples:
• rabies, malaria, Rocky
Mountain Fever
Tick
How Microorganisms
Grow in Humans
• Need:
– food
– oxygen
• aerobes-need oxygen
• anaerobes-do not need oxygen
– temperature
• 98.6 F or 36 C or warmer
– moisture
– pH
• acidity or alkalinity
Natural Defenses of the Host
• Hairs
– cilia
• Fluid
– tears, ear wax, blood
• Skin Tissue
– intact and healthy
• Proper Rest
• Proper Nutrition
• Natural Immunity
– childbirth & disease
process
• Phagocytosis
– cells that can destroy
bacteria
• Normal flora
– bacteria present that do
not normally cause
disease
– streptococci
Predisposing Factors
for Disease
•
•
•
•
•
•
•
•
Poor nutrition
Fatigue
Poor health habits
Pre-existing illness
Gender
Genetics
Climate/Weather
Occupational
• Age
– very young
– very old
• Medical treatment
– chemotherapy, radiation
therapy, bone morrow
transplants, immunosuppressed conditions,
indwelling catheters
Knowledge Assessment
•
•
•
•
1. Give the definition for microorganism.
2. List two examples of virus, bacteria, and fungi.
3. List the 3 required elements of the infection cycle.
4. Compare and contrast contact, droplet, and
airborne transmission of microorganisms.
• 5. List five natural defenses of the body.