Lecture Clinical procedures for medical assisting (4/e): Chapter 1 – Booth, Whicker, Wyman

CHAPTER

1

Principles of
Asepsis

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1­2

Learning Outcomes
1.1

Explain the historical background of
infectious disease prevention.

1.2

Identify the types of microorganisms that
cause disease.

1.3

List some infectious diseases, and identify
their signs and symptoms.

1.4

Discuss the importance of preventing

antibiotic resistance in a health-care setting.

1.5

Describe ways you can help prevent
antibiotic resistance in health-care settings.
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1­3

Learning Outcomes (cont.)
1.6

Explain the disease process.

1.7

Explain how the body’s defenses protect
against infection.

1.8

Describe the cycle of infection.

1.9

Identify and describe the various methods of
disease transmission.

1.10 Explain how you can help break the cycle of
infection.
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1­4

Introduction
Our bodies are amazing 
structures that defend us 
against infections under
normal circumstances
You will learn about:
– Disease-causing
microorganisms
– How the body fights
disease
– Ways infections occur

– Antibiotic-resistant
organisms
– Importance of patient
education on the proper
use of antibiotics

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1­5

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

1­6

(cont.)

Scientist

Contribution

Edward Jenner (1749–1823)

• Developed first effective
vaccine
• Used cowpox to vaccinate
against smallpox

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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History of Infectious Disease Prevention

1­7

(cont.)

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

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History of Infectious Disease Prevention

1­8

(cont.)

Scientist

Contribution

Robert 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

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History of Infectious Disease Prevention

1­9

(cont.)

• Remarkable advances in the past century
• Threat of infection still present
– New infectious diseases
• AIDS
• Ebola

– Resistant diseases
• MRSA
• VRSA
• Multidrug-resistant TB

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1­10

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.

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1­11

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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1­12

Microorganisms and Disease (cont.)
Classification

Characteristics

Example

Prions*

• Infectious particle
made of protein
• No nucleic acid
• Reproduction
unknown

Pr P

Disease
CreutzfeldtJakob
disease
Mad 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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1­13

Microorganisms and Disease (cont.)
Classification

Characteristics

Example

Disease

Viruses

• DNA or RNA
surrounded by protein
coat
• Reproduced in living
cells
• Very small

Varicellazoster virus

Chickenpox

Bacteria

•
•
•

Vibrio

cholerae

Cholera

Single-celled
Reproduce quickly
Mostly asexual
reproduction

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1­14

Microorganisms and Disease (cont.)
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

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1­15

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 microorganisms 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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1­16

Infectious Diseases
• Knowing signs and
symptoms of common
infectious diseases

can help protect
against exposure

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1­17

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

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1­18

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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1­19

Infectious Diseases (cont.)
Croup

• Most often caused by a virus
• Characterized by a harsh, barking cough,

difficulty breathing, hoarseness, and lowgrade 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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1­20

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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1­21

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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1­22

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

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1­23

Infectious Diseases (cont.)
Hepatitis

• Viral infection of liver
• Spread through blood or fecal-oral route

HIV/AIDS

• Human immunodeficiency virus
• Acquired immune deficiency syndrome

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1­24

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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1­25

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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