Unit 12 Infection Copyright 2008 Delmar Learning All

Objectives • Spell and define terms. • Identify the most common microbes and describe

Objectives • Define spores and explain how spores differ from other pathogens. • Name

Objectives • List natural body defenses against infections. • Explain why patients are at

Introduction • Humans are surrounded by a world of tiny organisms • These beings

Microbes • There are many different types of microbes – Many of which are

Bacteria • Simple one-celled microbes • Named according to their shapes and arrangement •

Fungi • Two groups of fungi are most commonly associated with infection in humans

Viruses • Smallest microbe • Has a variety of shapes Copyright © 2008 Delmar

Protozoa • Simple one-celled organisms • Live on living matter Copyright © 2008 Delmar

The Chain of Infection • Infections occur when certain conditions exist • Conditions are

The Chain of Infection Copyright © 2008 Delmar Learning. All rights reserved.

Chain of Infection • Breaking one link in the chain of infection is all

Chain of Infection Copyright © 2008 Delmar Learning. All rights reserved.

Causative Agent • Microorganism that can produce the disease process in humans Copyright ©

Susceptible Host • Person who can become infected with a pathogen • Unable to

Susceptible Host • Host is susceptible to the disease – Lacks immunity or physical

Reservoir • Where pathogens live, multiply, and survive • May or may not multiply

Reservoir • Source – Person, animal, or substance from which the infectious agent passes

Source • Reservoir may be the same as the source or different from the

Source • This distinction is important when deciding the types of precautions and control

Portals of Entry • Where organisms enter the body are called portals of entry

Portals of Entry • Portals – Body openings, mucous membranes, and breaks in the

Portals of Exit • Infectious organisms leave the reservoir of the human host through

Mode of Transmission • Mode or method of transmission: – Method by which the

Mode of Transmission • Methods of transmission are: – Direct contact – Indirect contact

Types of Infections • Infections can be: – Local – Generalized – Systemic Copyright

Body Flora • Different microbes live on our body surfaces – Microbes are called

Body Flora • They are not harmful in the area in which they normally

How Pathogens Affect the Body • Potential for infection depends on the risk factors

Body Defenses • The body has some natural defenses to protect itself from infections

Immunity • Immunity is the ability to fight off disease caused by microbes Copyright

Immunizations • Artificial defenses called immunizations protect against specific pathogens • Immunization is provided

Immunosuppression • Occurs when the body’s immune system is inadequate – Fails to respond

Serious Infections in Health Care Facilities • Serious bacterial and viral infections are increasing

Bacterial Infections • Bacteria are often the cause of serious skin, respiratory, urinary, and

MRSA and VRE • Two groups of organisms have become resistant to two powerful

Tuberculosis • Before the development of antibiotics: – Tuberculosis was a widespread disease with

Escherichia Coli 0157: H 7 • You have learned that Escherichia coli can cause

Pseudomembranous Colitis • Many bacteria live in the bowel of a healthy person •

Viral Infections • Viral infections include: – Shingles – Influenza – Hepatitis – Acquired

Other Important Infections • Infection caused by fungi: – Coccidioidomycosis • Infection caused by

Spores • Microscopic reproductive bodies are responsible for the spread of some diseases •

Spores • Avoid alcohol products for cleansing hands if a patient has a disease

Severe Acute Respiratory Syndrome • SARS is a highly contagious viral respiratory illness caused

Parasites • Survive by feeding off another human or animal – Head lice are

Parasites • Both head lice and scabies are known for spreading rapidly through health

Bedbugs • Are real parasites – Most people believe they are imaginary – Survive

Bedbugs • There is no recorded incidence of disease as a result of bedbugs,

Bedbugs • Bedbugs hide in or around the bed, including: – In the mattress

Bioterrorism • Use of biological agents – Pathogenic organisms or agricultural pests, for terrorist

Smallpox • Smallpox is a serious viral infection that is sometimes fatal • Disease

Outbreak of Infectious Disease in a Health Care Facility • An outbreak of an

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Objectives • Spell and define terms. • Identify the most common microbes and describe some of their characteristics. • List the links in the chain of infection. • List the ways that infectious diseases are spread. Copyright © 2008 Delmar Learning. All rights reserved.

Objectives • Define spores and explain how spores differ from other pathogens. • Name five serious infectious diseases. • Identify the causes of several important infectious diseases. • Describe common treatments for infectious disease. Copyright © 2008 Delmar Learning. All rights reserved.

Introduction • Humans are surrounded by a world of tiny organisms • These beings cannot be seen with the naked eye • They make their presence known only by their effects – Same way we become aware of the wind Copyright © 2008 Delmar Learning. All rights reserved.

Bacteria • Simple one-celled microbes • Named according to their shapes and arrangement • Cause infections in the skin, respiratory tract, urinary tract, and bloodstream Copyright © 2008 Delmar Learning. All rights reserved.

Susceptible Host • Person who can become infected with a pathogen • Unable to resist a microorganism invading the body, multiplying, and causing infection Copyright © 2008 Delmar Learning. All rights reserved.

Reservoir • Source – Person, animal, or substance from which the infectious agent passes to the host – May also be an inanimate object, such as water, a sink or counter top, or doorknob Copyright © 2008 Delmar Learning. All rights reserved.

Source • Reservoir may be the same as the source or different from the source – Reservoir is where the pathogen lives or resides – Source is the site from which the pathogen is transmitted to a susceptible host • Directly or indirectly through an object or in the environment Copyright © 2008 Delmar Learning. All rights reserved.

Portals of Entry • Portals – Body openings, mucous membranes, and breaks in the skin • Portals also result from tubes placed in body – Urinary catheters, or from punctures produced by invasive procedures such as intravenous fluids Copyright © 2008 Delmar Learning. All rights reserved.

Portals of Exit • Infectious organisms leave the reservoir of the human host through body secretions or portals of exit • Portal provides a way for a pathogen to leave the reservoir – Leaving nose or mouth on a sneeze or cough Copyright © 2008 Delmar Learning. All rights reserved.

Mode of Transmission • Mode or method of transmission: – Method by which the infectious agent passes from a source to the host – May be transmitted by more than one route Copyright © 2008 Delmar Learning. All rights reserved.

Mode of Transmission • Methods of transmission are: – Direct contact – Indirect contact – Airborne and droplet spread – Fomites (a method of indirect contact) – Vectors – Common vehicles Copyright © 2008 Delmar Learning. All rights reserved.

Body Flora • They are not harmful in the area in which they normally reside – But may cause infection if they are moved to another area of the body Copyright © 2008 Delmar Learning. All rights reserved.

How Pathogens Affect the Body • Potential for infection depends on the risk factors listed previously • Two major factors are: – Susceptibility of the host – Amount of infectious agent that finds a portal of entry into the host Copyright © 2008 Delmar Learning. All rights reserved.

Body Defenses • The body has some natural defenses to protect itself from infections • There are several natural external defenses • The most important of these is the skin Copyright © 2008 Delmar Learning. All rights reserved.

Immunosuppression • Occurs when the body’s immune system is inadequate – Fails to respond to the challenge of infectious disease organisms that it normally would fight successfully Copyright © 2008 Delmar Learning. All rights reserved.

Serious Infections in Health Care Facilities • Serious bacterial and viral infections are increasing in health care facilities as well as in the general public Copyright © 2008 Delmar Learning. All rights reserved.

Bacterial Infections • Bacteria are often the cause of serious skin, respiratory, urinary, and gastrointestinal infections in patients • If a physician suspects that a patient has a bacterial infection: – Culture and sensitivity test may be ordered Copyright © 2008 Delmar Learning. All rights reserved.

MRSA and VRE • Two groups of organisms have become resistant to two powerful antibiotics – Methicillin and vancomycin • These organisms are: – Methicillin-resistant Staphylococcus aureus (MRSA) – Vancomycin-resistant enterococci (VRE) Copyright © 2008 Delmar Learning. All rights reserved.

Tuberculosis • Before the development of antibiotics: – Tuberculosis was a widespread disease with a high fatality rate • In the 1950 s: – Use of antibiotics effective against tuberculosis caused deaths to drop sharply Copyright © 2008 Delmar Learning. All rights reserved.

Escherichia Coli 0157: H 7 • You have learned that Escherichia coli can cause serious problems outside the intestinal tract. • E. coli 0157: H 7 – Caused outbreaks resulting in serious illness and death Copyright © 2008 Delmar Learning. All rights reserved.

Pseudomembranous Colitis • Many bacteria live in the bowel of a healthy person • Most of them are harmless – Some friendly bacteria help with digestion • A few of these have the potential to be troublemakers if they get out of control Copyright © 2008 Delmar Learning. All rights reserved.

Spores • Microscopic reproductive bodies are responsible for the spread of some diseases • They can survive in a dormant form until conditions are ideal for reproduction • Spores will multiply and continue to spread infection • They are very difficult to eliminate Copyright © 2008 Delmar Learning. All rights reserved.

Spores • Avoid alcohol products for cleansing hands if a patient has a disease spread by spores: – Alcohol will not kill spores – Mechanical action of washing with soap and water loosens spores and washes them down the drain Copyright © 2008 Delmar Learning. All rights reserved.

Severe Acute Respiratory Syndrome • SARS is a highly contagious viral respiratory illness caused by a coronavirus • Special isolation precautions are required • Much remains to be learned about SARS Copyright © 2008 Delmar Learning. All rights reserved.

Parasites • Survive by feeding off another human or animal – Head lice are parasites that spread by direct and indirect contact – Scabies is a skin disease caused by a parasite called a mite – Mites are microscopic organisms that cannot be seen with the eye Copyright © 2008 Delmar Learning. All rights reserved.

Bedbugs • There is no recorded incidence of disease as a result of bedbugs, although it is suspected • Bites cause a painful rash on the skin • Bedbugs feed at night Copyright © 2008 Delmar Learning. All rights reserved.

Smallpox • Smallpox is a serious viral infection that is sometimes fatal • Disease emerged thousands of years ago but was eliminated during the twentieth century Copyright © 2008 Delmar Learning. All rights reserved.

Outbreak of Infectious Disease in a Health Care Facility • An outbreak of an infection in a health care facility can be serious for all patients • Unless steps are taken immediately – Infection can spread rapidly Copyright © 2008 Delmar Learning. All rights reserved.