Infection
Unit 12
Understanding Microbes
• Location of microbes:
• Skin
• Mouth
• Within our bodies (intestines)
• In and on food we eat (meats, condiments)
• On what we touch or handle (desk, doors,
handrails, etc.)
• Nonpathogens: microbes that are useful to us. They
do not cause disease.
• Pathogens: disease-producing organisms; they
grow best in warm, moist, dark environment where
food and oxygen needs can be met.
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Classification of Microbes
• Protozoa: Simple, one-celled parasitic organisms
• Bacteria: Simple, one-celled microbes
• Fungi: Two Types –
• Yeast: Simple, one-celled budding form of a
fungus
• Mold: saprophytic (organism that lives on dead matter)
fungi that can cause mold or moldiness
• Viruses: smallest microbe that depends completely
on the invaded host cells for reproduction
• Usually spread in blood, secretions from
respiratory, intestinal tracts or reproductive tracts
• Can cause serious illness – no cure
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Infectious Disease Process
• Chain of Infection: Six components:
• Causative Agent: microorganism that causes
disease
• Reservoir for Agent: where causative agent lives
• Human
• Environmental
• Can leave reservoir by secretions in body fluid
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Infectious Disease Process
• Mode of Transmission: way disease is spread
• Airborne (float through air)
• Droplet (coughing/sneezing)
• Contact (direct touch)
• Common Vehicle (instrument(s))
• Vector-borne (fleas, ticks, mosquitoes)
• Portal of Entry: entry made through:
• Breakthroughs in the skin
• Inhalation
• Sexual transmission
• Ingestion
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Infectious Disease Process
• Susceptible Host: person who is likely to get
infection:
• Very young (immature immune system)
• Very old (declining immune system)
• Persons with compromised immune systems
• Portal of Exit: area through which infectious
secretions leave the body
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Chain of
Infection
Causative
Agent
Susceptible
Host
Reservoir or
Source
Portal of
Entry
Portal of
Exit
Method of
Transmission
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Infectious Disease Process
• Risk Factors:
• Strength of immune system
• Compromised immunity (example: HIV/AIDS)
• Not being vaccinated
• Other factors: age, heredity, sex, nutritional
status, life-style, occupation, and stress.
• Any breakdown of the bodies natural defenses
(example: skin breakdown)
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Infections
• Infections can be:
• Local (an infected abrasion)
• Generalized (infected hand from infected
laceration)
• Systemic (in the blood stream)
• Carriers: people who have pathogens in their
bodies, but do not show signs of infections; these
people can transmit disease to others
• Normal Flora: microbes living in the body that can
cause infection if they become pathogenic; or move
from one area of the body to another area where they
don’t belong, or if antibiotics given for another
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infection upset the normal balance of flora.
How Pathogens Affect The Body
• An infection cannot occur unless all links in the
chain of infection are present.
• Microbes act in different ways to produce disease;
• Attack and destroy cells
• Produce toxins
• Cause allergies
• Internal defenses against pathogens:
• Fever
• Inflammation
• Phagocytes
• Immune response
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Immunity
• Immunity: the ability to resist infection
• When pathogen enters body, it becomes an
antigen.
• The body develops antibodies to protect against
the antigen and provide immunity from disease
• Vaccinations of artificial or weakened antigens help
the body develop antibodies to resist certain
diseases.
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Immunity
• Immunosuppression: when the immune system is
unable to fight/resist disease
• Advanced age
• HIV
• Spleen injury
• Chemo Therapy
• Radiation Therapy
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Serious Infections In Health Care Facilities
• Bacteria: can cause skin, respiratory, and urinary
infections
• Diagnosed by way of a culture and sensitivity test
(to antibiotic)
• Antibiotics: need to be taken as prescribed until
they are all finished – even if patient feels symptom
free!
• Drug resistance may develop, if the antibiotics are
stopped too soon
• Antibiotic Resistant Pathogens: pathogens that are
resistant to most antibiotics
• Can cause serious infections
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• MRSA (methicillin resistant staphylococcus aureus)
Serious Infections In Health Care Facilities
• Antibiotic Resistant Pathogens: pathogens that
are resistant to most antibiotics
• Can cause serious infections
• MRSA (methicillin resistant staphylococcus
aureus)
• VRE (vancomycin resistant enterrococci)
• Other serious pathogens:
• Pseudomonas aeroginosa
• Escherrichia coli (E-coli)
• Streptococcus A
• Salmonella
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• Mycobacterium Tuberculosis (TB)
Serious Infections In Health Care Facilities
• Tuberculosis (TB): was a widespread disease with
a high fatality rate prior to the development of
antibiotics
• New cases have increased since 1985 (drugresistant)
• People at high risk for TB:
• HIV positive
• Those living in poverty
• Immigrants from countries where TB is common
• Individuals that have had TB exposure
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Serious Infections In Health Care Facilities
• Signs & Symptoms of Tuberculosis (TB):
• Fatigue
• Weight loss
• Loss of appetite
• Weakness
• Elevated temperature in afternoon/evening
• Night sweats
• Hemoptysis (coughing up blood)
• Coughing
• Can be spread through droplets in respiratory
secretions
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Serious Infections In Health Care Facilities
• Can be diagnosed by:
• Sputum culture
• Chest x-ray
• Positive skin test (Mantoux test)
• Treatment:
• Antibiotics for 6 months to 2 years
• They are initially contagious for 2-3 weeks
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Serious Infections In Health Care Facilities
• Escherrichia Coli (E-coli):
• Transmitted in
• Contaminated or undercooked meat
• Produce that has been rinsed in water
contaminated with feces
• Has been found on cutting boards and utensils
• Multiplies rapidly
• Produces toxins
• Causes diarrhea, dehydration, renal failure
• Standard precautions are used (gloves,
handwashing), but contact precautions are used
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for diapered (infants/adults) or incontinent patients
Serious Infections In Health Care Facilities
• Pseudomembranous colitis: caused by Clostridium
difficile (C-diff), common pathogen in health care
facilities
• Picked up on hands from contaminated
environmental surfaces and equipment
• Frequent, severe diarrhea and dehydration
• Standard/contact precautions
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Viral Infections
• Shingles (herpes zoster): occurs in people infected
with chicken pox, but the virus remained in the body
in an inactive state; years later it becomes active,
causing painful blisters
• Influenza (flu): caused by a family of viruses and
can lead to serious complications. Some types of flu
may be prevented with vaccinations
• Hepatitis: inflammation of the liver that can be
caused by several different viruses; Hep A, Hep B,
and Hep C are the most common
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Viral Infections
• Acquired immune deficiency syndrome (AIDS):
caused by human immunodeficiency virus;
transmitted primarily through direct contact of
secretions of another person’s infected bodily
secretions
• Blood
• Vaginal secretions
• Semen
• Saliva
• Breast milk
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Viral Infections
• Human Immunodeficiency Virus (HIV): has many
variants and does not live long outside of the body;
can be eliminated by common chemicals such as
bleach
• Depresses body’s immune system and makes
the infected person more susceptible to infections
and other complications; not everyone who is
exposed becomes infected
• Following infection with HIV, virus may not be
immediately active – yet the person IS
INFECTED. Most will show antibodies to HIV in
blood within 3 to 6 months after infection.
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Viral Infections
• Human Immunodeficiency Virus (HIV):
• Infection with HIV is called HIV disease; this
condition may progress to AIDS
• HIV may not ever develop into AIDS, but person is
a carrier of disease and is able to infect others
• Progression of HIV disease is seen by a decrease
in CD4 (T4) cells; as a result the immune system is
suppressed and the ability to resist infection
decreases
• When CD4 level drops to <200, the person is
diagnosed with AIDS (Normal= 600-1500/µL)
• Risky behavior should be avoided!
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Viral Infections
• Human Immunodeficiency Virus (HIV):
• Symptoms:
• Flu-like:
• Fever
• Night sweats
• Fatigue
• Swollen lymph nodes
• Sore throat
• Gastrointestinal problems
• Headache
• ¼ to ½ of those infected show signs of illness26
within 5-10 years of antibody development
Viral Infections
• Human Immunodeficiency Virus (HIV):
• No vaccine is available to prevent HIV/AIDS
• Therapy consists of drugs that slow down the
disease process and reinforce the immune system
• Some drugs are used to prevent and treat infection
• Nutritional support is also very important
• Drug therapy must be taken EXACTLY as
prescribed or the condition will worsen
• The is no cure for this disease
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Viral Infections
• Hantavirus:
• Spread by contact with rodents or their excrement
(poop)
• When disturbed, viral particles in the excretions
become airborne and are inhaled by susceptible
hosts
• As disease progresses, patient becomes very short
of breath, eventually requiring respiratory support
(ventilator)
• Not transmitted from person to person
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Other Important Infections
• Coccidoidomycosis (valley fever): respiratory
infection caused by a fungus; can be fatal in
immunosuppressed persons
• Giardiasis: protozoa found in water; causes severe
diarrhea; can be treated with antibiotics
• Cryptospoidiosis: protozoa found in digestive tract
of infected animals; causes severe diarrhea; no
specific treatment
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Other Important Infections
• Guidelines for preventing infections:
• Maintain adequate fluid/nutritional intake
• Toilet patients regularly
• Wipe from FRONT to BACK – always!
• Perform catheter care as directed; avoid opening
the closed drainage system
• Keep patients clean
• Avoid reporting to work ill
• Follow facility’s policies on infection control
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Other Important Infections
• Guidelines for preventing infections:
Promptly Report Abnormalities In:
Urine
Discharge from wound
Respirations
Change in skin color
Mental changes
Nausea/vomiting
Bowel Pattern
Red/swollen areas on
body
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Bioterrorism
• Bioterrorism: use of biological agents, including
pathogens or agricultural pests, for terrorist purposes
• Many individuals can be affected by a biological
weapon before the cause is detected
• Smallpox is a serious viral infection that was
eliminated during the 20th century, but contained
stockpiles still exist in laboratories around the
world
• Hospitals have a voluntary smallpox vaccination
program for workers which provides high-level
immunity for 3-5 years, then immunity gradually
decreases
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• Vaccine contains LIVE virus
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Bioterrorism
• Anthrax (Bacillus anthracis) is a bacteria that can form
endospores.
• Endospores can live for centuries!
• Spores can be used as a biological weapon
• Causes fatal pneumonia if inhaled
• Cause skin lesions on contact
• Anthrax toxin used as a weapon and instantly fatal if
inhaled.
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Bioterrorism
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Outbreak of Disease in Health Care Facility
• If outbreak is detected: immediate action must be
taken to contain infection
• Nursing assistants will receive specific instructions
regarding precautions to be taken as well as
containment procedures
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Self Care
• The nursing assistant can stay healthy by
• eating a healthy diet
• getting adequate sleep
• keeping body clean
• living in clean environment
• have mechanisms to effectively deal with stress
• avoid unhealthy habits (smoking/drugs/alcohol)
• avoid risky behaviors/situations
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The End
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