19-1 © 2009 the mcgraw-hill companies, inc. all rights reserved principles of asepsis powerpoint®...
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19-1
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
Principles of AsepsisPrinciples of AsepsisPowerPoint® presentation to accompany:
Medical AssistingThird Edition
Booth, Whicker, Wyman, Pugh, Thompson
19-2
© 2009 The McGraw-Hill Companies, Inc. All rights reserved
Learning Outcomes
19.1 Explain the historical background of infectious disease prevention.
19.2 Identify the types of microorganisms that cause disease.
19.3 List some infectious diseases, and identify their signs and symptoms.
19.4 Discuss the importance of preventing antibiotic resistance in a health-care setting.
19.5 Describe ways you can help prevent antibiotic resistance in health-care settings.
19-3
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Learning Outcomes (cont.)
19.6 Explain the disease process.
19.7 Explain how the body’s defenses protect against infection.
19.8 Describe the cycle of infection.
19.9 Identify and describe the various methods of disease transmission.
19.10 Explain how you can help break the cycle of infection.
19-4
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Introduction
Antibiotic-resistant organisms
Importance of patient education on the proper use of antibiotics
You will learn about: Disease-causing
microorganisms How the body fights disease Ways infections occur
Our bodies are amazing structures that defend us against infections undernormal circumstances
19-5
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History of Infectious Disease Prevention Throughout history
people have attempted to discover
Causes of infection
How to prevent infections
How to treat infections
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History of Infectious Disease Prevention (cont.)
Scientist ContributionEdward Jenner (1749–1823) Developed first effective
vaccine Used cowpox to vaccinate against small pox
Ignaz Semmelweis (1818–1865) and Oliver Wendell Holmes (1809–1894)
Promoted handwashing as a means of reducing the spread of Puerperal fever to women in childbirth
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Scientist Contribution
Louis Pasteur (1822–1895) Helped develop the germ theory of infectious disease stating that disease is caused by microorganisms
Joseph Lister (1827–1912) Helped develop germ theory Introduced aseptic
techniques through the use of antiseptics on wounds, surgical sites, and surgical instruments
History of Infectious Disease Prevention (cont.)
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Scientist ContributionRobert Koch (1843–1910) Developed a set of proofs,
known as Koch’s Postulates, claiming that microbes cause disease
Sir Alexander Fleming (1881–1955)
Discovered penicillin
History of Infectious Disease Prevention (cont.)
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Remarkable advances in the past century Threat of infection still present
New infectious diseases AIDS Ebola
Resistant diseases MRSA VRSA Multidrug-resistant TB
History of Infectious Disease Prevention (cont.)
19-10
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Apply Your Knowledge
Why is the threat of infection still present even though great advances have been made in controlling infections over the past century?
ANSWER: The threat of infection is still present because of new diseases and diseases that have become resistant to treatments.
19-11
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Microorganisms and Disease Microorganisms live all around us
Pathogens Microorganisms capable of causing disease Evade host defenses
People avoid infections most of the time Many microorganisms are beneficial or harmless Normal defenses resist infection Conditions are not favorable for pathogens to grow and
be transmitted
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Microorganisms and Disease (cont.)
Classification
Characteristics Example
Disease
Prions * Infectious particle made of protein
No nucleic acid Reproduction
unknown
Pr P CJD
BSEMad cow disease
* Experts disagree as to whether prions are directly responsible for disease or merely aid an unknown agent in causing disease.
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Classification
Characteristics
Example
Disease
Viruses DNA or RNA surrounded by protein coat
Reproduced in living cells
Very small
Varicella-zoster virus
Chickenpox
Bacteria Single-celled Reproduce quickly Mostly asexual reproduction
Vibrio cholerae
Cholera
Microorganisms and Disease (cont.)
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Classification
Characteristics Example Disease
Protozoans Single-celled Reproduction mostly asexual
Entamoeba histolytica
Amebic dysentery
Fungi Multicellular Reproduction is sexual and asexual
Candida albicans
Candidiasis
Helminths Multicellular parasitic Contain specialized organs Sexual reproduction
Enterobius vermicularis
Pinworms
Microorganisms and Disease (cont.)
19-15
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Apply Your Knowledge
In many cases, we avoid contracting infections when exposed to microorganisms. What are the reasons for this?
ANSWER: This is because:
many microorganism are beneficial or harmless
we have normal defenses to resist infection
conditions are not favorable for the pathogen to grow and be transmitted.
Correct!
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Infectious Diseases Knowing signs and
symptoms of common infectious diseases can help protect against exposure
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Infectious Diseases (cont.)
Chickenpox (Varicella)
Contagious viral infection Incubation period of 7 to 21 days Itchy rash fluid-filled blisters Slight fever, headache, general malaise Spread by direct, indirect, droplet, or airborne transmission Isolate until all blisters have scabbed over 1996 – live vaccine approved
19-18
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Infectious Diseases (cont.)
Common cold
Viral infections of upper respiratory tract No isolation needed Commonsense precautions to prevent
spread Use tissues when coughing or sneezing Wash hands frequently Use disposable dishware, if possible
Incubation – 2 to 3 days
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Infectious Diseases (cont.)
Croup Most often caused by a virus Characterized by a harsh, barking cough,
difficulty breathing, hoarseness, and low-grade fever
Most common in infants and young children
Symptoms lessened by humidification of air, rest, and clear fluids
Commonsense precautions to prevent spread
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Infectious Diseases (cont.)
Diphtheria Bacterial infection of nose, throat, and larynx
Symptoms: pain, fever, respiratory obstruction
Incubation – 2 to 5 days Isolation required Antibiotic therapy (fatal if untreated) Immunization available
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Infectious Diseases (cont.)
Epstein-Barr Virus
Common human virus 95% of adults have had virus
35 – 50% of teens develop mononucleosis
Symptoms – fever, sore throat, swollen lymph nodes
Virus remains dormant for life Occasionally reactivates as tumors
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Infectious Diseases (cont.)
Haemophilus Influenzae Type B
Bacterial infections in infants and young children
Spread – direct, indirect, and droplet transmission
Incubation – 3 days Upper respiratory symptoms, fever,
drowsiness, body aches, diminished appetite
Monitor closely – bacterial meningitis
19-23
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Infectious Diseases (cont.)
Hepatitis Viral infection of liver Spread through blood or fecal-oral
route
HIV/AIDS Human immunodeficiency virus Acquired immune deficiency syndrome
19-24
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Infectious Diseases (cont.)
Influenza (Flu)
Symptoms – fever, chills, headaches, body aches, upper respiratory congestion
Isolation and commonsense precautions Vaccines
Live, attenuated virus – nasal spray Inactivated virus – IM injection
Annual vaccination People at risk for complications
People older than 50 years old People in close contact with persons at risk for
complications
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Infectious Diseases (cont.)
Measles (Rubeola)
Infectious viral disease Spread by droplets or direct transmission Initial symptom of fever develops 8 to 13
days after exposure, followed by a characteristic itchy rash 14 days after exposure
Isolation for 7 days after rash appears Keep children under 3 years old away from
anyone with the disease Reportable to state or county health dept.
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Infectious Diseases (cont.)
Meningitis Inflammation and infection of protective coverings of brain and spinal cord and the fluids around them
Viral – milder form Clears in 1 to 2 weeks without treatment Aseptic meningitis
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Infectious Diseases (cont.)
Meningitis Bacterial – serious, life-threatening, requiring immediate treatment Vaccination available for people in high-risk
groups Symptoms – red, blotchy rash, confusion,
delirium, light sensitivity, headache, fever and chills, nausea and vomiting, sleepiness, stiff neck
May spread through exchange of respiratory and throat secretions
Reportable to state or county health dept.
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Infectious Diseases (cont.)
Mumps Viral infection Primarily affects salivary glands
Incubation – 2 to 3 weeks Pain related to inflammation of parotid
gland and fever Isolate until glandular swelling stops Reportable to state or county health
dept.
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Infectious Diseases (cont.)
Pertussis (Whooping Cough)
Highly contagious bacterial infection of respiratory tract
Symptoms – fever, sneezing, runny nose, quick short coughs, characteristic “whoop” during inhaled breath following coughing fit
Isolate for 3 weeks following onset of spasmodic coughs
Reportable to state or county health dept.
19-30
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Infectious Diseases (cont.)
Roseola Rose-colored rash possibly caused by human herpes virus
Infants and young children Incubation 5 to 15 days Symptoms – sudden, high fever; sore throat;
swollen lymph nodes; rash
Rubella (German Measles)
Highly contagious viral disease Direct or droplet transmission Incubation 16 to 18 days Symptoms – fever and itchy rash Vaccination available Reportable
19-31
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Infectious Diseases (cont.)
Streptococcal pharyngitis (strep throat)
Bacterial infection of throat Sore throat, swelling of pharyngeal mucosa, fever, headache, nausea, abdominal pain Treat with antibiotics
Scarlet fever Bacteria becomes systemic Characteristic “strawberry rash” Incubation 7 to 10 days Isolate 7 days
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Infectious Diseases (cont.)
Streptococcal pharyngitis(cont.)
Rheumatic fever Occurs after apparent recovery from strep throat Autoimmune disorder – antibodies to
streptococci cross-react with heart tissues Symptoms – carditis, ECG changes, joint pain
and inflammation, fever
Acute post-streptococcal glomerulonephritis Inflammation of glomerulus of the kidney
resulting in inadequate filtering of the blood Symptoms – swelling of hands and feet,
decreased urine output, hypertension, protein in urine
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Infectious Diseases (cont.)
Tetanus Acute infectious bacterial disease following a contaminated puncture wound
Incubation – 3 to 21 days Late symptoms – lockjaw, paralysis No isolation needed, but reportable
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Infectious Diseases (cont.)
Tuberculosis Infectious bacterial disease affecting mainly lungs Symptoms – night sweats, productive cough, fever, chills, fatigue, unexplained weight loss, diminished appetite, bloody sputum
Incidence – higher in urban centers
Transmission Mycobacterium tuberculosis Droplet
19-35
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Infectious Diseases (cont.)
Tuberculosis (cont.)
Increasing resistance to TB Early diagnosis, prompt treatment Compliance with treatment regimen
Preventing TB Vaccination – BCG (not used in the U.S.) Causes false-positive with TB skin test
19-36
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Infectious Diseases (cont.)
Tuberculosis (cont.)
Treating TB Mantoux TB test
Positive test = Induration – skin turns red and becomes raised and hard Positive result from immunization or exposure to TB bacteria
Treatment based on area affected and type of TB involved Patients must complete entire course of treatment – 12 to 18 months on medication Isolation
19-37
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Apply Your Knowledge
ANSWER: The spread of many infectious diseases can be limited or prevented by using common sense precautions: Using tissues when coughing or sneezing Washing hands frequently Using disposable dishware
How can the spread of many infectious diseases can be limited or prevented?
Excellent!
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Drug-Resistant Microorganisms MRSA – methicillin/oxacillin-resistant S. aureus
VRE – vancomycin-resistant enterococci
VISA – vancomycin-intermediate S. aureus
VRSA – vancomycin-resistant S. aureus
ESBLS – extended-spectrum beta-lactamases
PRSP – penicillin-resistant Streptococcus pneumoniae
19-39
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Drug-Resistant Microorganisms (cont.)
MRSA and VRE Most common in non-hospital health-care facilities
Community-associated MRSA Increasing in incidence
PRSP Common in patients seeking care in physicians’ offices
and clinics (pediatrics)
19-40
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Drug-Resistant Microorganisms (cont.)
Risk factors for development of infections by drug-resistant organisms Advanced age Invasive procedures Prior use of antibiotics Repeated contact with health-care system Severity of illness Underlying diseases of conditions
19-41
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Drug-Resistant Microorganisms (cont.)
Preventing antibiotic resistance Four strategies to reduce incidence of antibiotic-
resistant microorganisms Prevent infection Diagnose and treat infection
appropriately Use antibiotics carefully Prevent transmission of
infections
19-42
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Apply Your Knowledge
What strategies reduce the incidence of antibiotic-resistant microorganisms?
ANSWER: Strategies to reduce the incidence of antibiotic-resistant microorganisms include:
Prevent infections
Diagnose and treat infections appropriately
Use antibiotics carefully
Prevent transmission
Good Job!
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Disease Process Begins with
microorganisms finding host
Grows with specific requirements
Proper temperature
pH
Moisture level
Virulence – microorganism’s disease-producing power
Damage is caused by:
Depleting nutrients
Reproducing themselves
Making body cells the target of body’s own defenses
Producing toxins
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Disease Process (cont.)
Once exposed to a pathogen, the body goes through 4 stages of illness:
Incubation – begins at first exposure; ends when first symptom appears
Prodromal – begins at first onset of symptoms; generally short
Invasion – numbers of organisms are greatest; symptoms are most pronounced
Convalescent – patient regains normal health status
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Apply Your Knowledge
ANSWER: The four stages of illness are: Incubation – begins at first exposure; ends when first symptom appears Prodromal – begins at first onset of symptoms; generally short Invasion – numbers of organisms are greatest; symptoms are most pronounced Convalescent – patient regains normal health status
What are the four stages of illness?
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The Body’s Defenses Immunity – condition
of being resistant to pathogens and the disease they cause
First lines of defense Skin Sweat glands Mucous membranes Cilia Lacrimal glands Saliva Hydrochloric acid Lysozyme
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The Body’s Defenses (cont.)
Resident normal flora – microorganisms found in the body Provide a barrier against pathogens
Normally live in balance
Become pathogenic when host’s defenses are compromised
Opportunistic infections Infections occurring when a host’s resistance is low
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The Body’s Defenses (cont.)
Immune system includes nonspecific defenses Mechanisms to protect against pathogens in
general Includes
Nonspecific defenses Humoral defenses Cell-mediated defenses
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The Body’s Defenses: Nonspecific Inflammation
Signs Redness Localized heat Swelling Pain
Purpose Summon immunologic
agents to site Begin tissue repair Destroy invading
microorganisms
Steps1. Initial constriction, then
dilation of blood vessels, causing redness and heat
2. Fluid leakage from local vessels swelling
3. Scar tissue formation
Chronic inflammation damages tissues and causes permanent loss of function
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The Body’s Defenses: Nonspecific (cont.)
Phagocytosis White blood cells (phagocytes)
engulf and digest pathogens Three types
Neutrophils – found in pus Monocytes – formed in bone marrow and become Macrophages when they migrate to specific tissues
Found in lymph nodes, liver, spleen, lungs, bone marrow, and connective tissue
Deliver antigens (foreign substances) to lymphocytes
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The Body’s Defenses: Humoral Immunity Lymphocytes – B cells and T cells
T cells activate B cells to produce antibodies to neutralize an antigen
Memory B cells respond quickly to produce antibodies in later invasions
Specific antibodies are produced in response to specific antigens
Antibodies attract phagocytes, which destroy antigens
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Types of immunity Active – body produces own antibodies
Natural active Artificial active
Passive – antibodies that are produced outside body enter the body Natural passive Artificial passive
Complement Proteins activated by antibodies Helps white blood cells destroy pathogens
The Body’s Defenses: Humoral Immunity (cont.)
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The Body’s Defenses: Cell-Mediated Immunity
T cells attack invading pathogen directly Helper T cells
Activate
Killer T cells Bind with antigen and kill it
Suppressor T cells Slow down or stop attack after antigen is destroyed
Memory T cells Respond quickly to another attack by same antigen
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Apply Your Knowledge
What is the difference between active and passive immunity?
ANSWER: Active immunity is long-term immunity in which the body produces its own antibodies.
Passive immunity results when antibodies produced outside the body enter the body.
Both can be natural or artificial.
Impressive!
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Cycle of Infection A reservoir host – animal, insect, or human
body capable of sustaining pathogen growth Carrier – unaware of presence of pathogen Subclinical case – unnoticeable infection Endogenous infection – normally harmless
microorganisms become pathogenic Exogenous infection – pathogen introduced
into the body
Click for Cycle of Infection
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Cycle of Infection (cont.)
Means of exit – how the pathogen leaves the host Nose, mouth, eyes, or ears Feces or urine Semen, vaginal fluid, or other
reproductive discharge Blood or blood products
Click for Cycle of Infection
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Cycle of Infection (cont.) Means of transportation – how a pathogen spreads
to a host Airborne Blood-borne During pregnancy or birth Foodborne Vector-borne
Living organism that carries microorganisms to another person
Touching Direct Indirect through
fomites Inanimate reservoir
of pathogens Drinking glass,
door knob, etc.
Click for Cycle of Infection
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Means of entrance Enter through any cavity lined
with mucous membrane Mouth, nose, vagina, rectum Ears, eyes, intestinal tract, urinary
tract, reproductive tract, breaks in the skin
Cycle of Infection (cont.)
Click for Cycle
of Infection
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Cycle of Infection (cont.)
Pathogen factors Number and
concentration
Virulence
Point of entry
Susceptible host Individual with little or no
immunity to infection by a pathogen
Host factors influencing susceptibility Age Genetic predisposition Nutritional status Other disease processes Stress levels Hygiene habits General health
Click for Cycle of Infection
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Cycle of Infection (cont.)
Back
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Cycle of Infection (cont.)
Environmental factors Dense populations Animals
Unpasteurized milk Insects Economic and political factors Availability of transportation Population growth rates Sexual behavior
19-62
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Apply Your Knowledge
ANSWER: Fomites are inanimate objects such as clothing, water, and food that serve as a means of transportation for microorganisms.
What are fomites?
Nice Job!
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Breaking the Cycle Asepsis – condition in which
pathogens are absent or controlled Maintain strict housekeeping
standards Adhere to government
guidelines to protect against disease
Educate patients in hygiene, health promotion, and disease prevention
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In Summary
Medical Assistant
Must learn how pathogens cause disease, how disease is transmitted, and how to prevent the spread of infection.
As knowledge about causes of infection have increased, principles and practices of asepsis have developed.
Use this knowledge to educate patients about remaining healthy and decreasing the risk of contracting disease.
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End of Chapter
In today's world, new infections and
diseases can spread across the country
and even across the world in a matter of
days, or even hours, making early
detection critical.
~ John Linder
U.S. Representative, Georgia