Harmful Bacteria
Jessica Harwood
Douglas Wilkin, Ph.D.
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AUTHORS
Jessica Harwood
Douglas Wilkin, Ph.D.
EDITOR
Douglas Wilkin, Ph.D.
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Printed: February 15, 2015
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C HAPTER
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Chapter 1. Harmful Bacteria
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Harmful Bacteria
Describe how some bacteria are harmful.
Name human diseases caused by bacteria.
Describe bacterial contamination of foods.
Explain the use of bacteria as a weapon.
Could this organism make you sick?
This bacterium, called Mycobacterium tuberculosis, causes the disease Tuberculosis (TB). These bacteria usually
attack the lungs. If left untreated, the infection can be fatal. Many other illnesses, mild and severe, are also caused
by certain types of bacteria.
Harmful Bacteria
With so many species of bacteria, some are bound to be harmful. Harmful bacteria can make you sick. They can
also ruin food and be used to hurt people.
Diseases
There are also ways that bacteria can be harmful to humans and other animals. Bacteria are responsible for many
types of human illness ( Figure 1.1), including:
• Strep throat
• Tuberculosis
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• Pneumonia
• Leprosy
• Lyme disease
Luckily most of these can be treated with antibiotics.
FIGURE 1.1
The Black Death, which killed at least one
third of Europe’s population in the 1300s,
is believed to have been caused by the
bacterium Yersinia pestis.
Food Contamination
Bacterial contamination of foods can lead to digestive problems, an illness known as food poisoning. Raw eggs and
undercooked meats commonly carry the bacteria that can cause food poisoning. Food poisoning can be prevented
by cooking meat thoroughly and washing surfaces that have been in contact with raw meat. Washing your hands
before and after handling food also helps prevent contamination.
Weapons
Some bacteria also have the potential to be used as biological weapons by terrorists. An example is anthrax, a disease
caused by the bacterium Bacillus anthracis. Inhaling the spores of this bacterium can lead to a deadly infection, and,
therefore, it is a dangerous weapon. In 2001, an act of terrorism in the United States involved B. anthracis spores
sent in letters through the mail.
Summary
• Bacteria are responsible for many types of diseases in humans.
• Some bacteria can contaminate food and cause food poisoning.
• Some bacteria have been used as biological weapons by terrorists.
Explore More
Use these resources to answer the questions that follow.
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Chapter 1. Harmful Bacteria
Explore More I
• http://www.youtube.com/watch?v=j5GvvQJVD_Y (5:06)
MEDIA
Click image to the left or use the URL below.
URL: http://www.ck12.org/flx/render/embeddedobject/57429
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How does infection by the bacteria Salmonella typhimurium begin? Do all bacterial infections start this way?
Do all bacteria ingested make it to the intestines? Why or why not?
What does Salmonella typhimurium compete with in the intestines?
What are some possible effects of infection by Salmonella typhimurium?
Explore More II
• KidsHealth Food Poisoning at http://kidshealth.org/kid/ill_injure/sick/food_poisoning.html .
1. What are the common bacteria that cause food poisoning?
2. What steps can you take to keep your food safe?
Review
1. What are three examples of diseases caused by bacteria?
2. How can you prevent food poisoning?
3. How are bacterial diseases treated?
References
1. Unknown. Drawing of the Black Death, caused by the bacteria Yersinia pestis . Public Domain
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