Introduction to Antibiotics
Author: Rachel Hughes
Time:
1 class period
Preparation
Copying-30 minutes
Time:
Materials:
chart
computer access/library access
Abstract
Stumbling into the doctor’s office, the patient demands some antibiotics, but is that what is really
needed? In this exercise students are briefly introduced to the idea of antibiotic resistance as a
way to focus on antibiotics and the mechanisms by which they work. (Antibiotic resistance will be
covered in more detail in later classes.) Students decide whether antibiotics are the right
prescription or not. Working as a group, students review multiple illnesses and make the decision.
Objectives
Students will be able to:
1. describe the impact of antibiotics on disease
2. describe what infections antibiotics are useful for
National Science Education Standard:
CONTENT STANDARD F: Science in Personal and Social Perspectives
PERSONAL AND COMMUNITY HEALTH
The severity of disease symptoms is dependent on many factors, such as human resistance and
the virulence of the disease-producing organism. Many diseases can be prevented, controlled, or
cured. Some diseases, such as cancer, result from specific body dysfunctions and cannot be
transmitted.
CONTENT STANDARD G: History and Nature of Science
HISTORICAL PERSPECTIVES
In history, diverse cultures have contributed scientific knowledge and technologic inventions.
Modern science began to evolve rapidly in Europe several hundred years ago. During the past
two centuries, it has contributed significantly to the industrialization of Western and non-Western
cultures. However, other, non-European cultures have developed scientific ideas and solved
human problems through technology.
Usually, changes in science occur as small modifications in extant knowledge. The daily work of
science and engineering results in incremental advances in our understanding of the world and
our ability to meet human needs and aspirations. Much can be learned about the internal
workings of science and the nature of science from study of individual scientists, their daily work,
and their efforts to advance scientific knowledge in their area of study.
Occasionally, there are advances in science and technology that have important and long-lasting
effects on science and society. Examples of such advances include the following
Teacher Background
A seemingly incidental discovery had a revolutionary impact on medicine. Alexander Fleming
discovered penicillin, a mold growing on some Petri dishes and also noted that where the
penicillin grew, the bacteria did not. What Fleming found revolutionized medicine, as these
antibiotics were able to target bacterial cells, leaving the host relatively unaffected. This
significantly reduced the loss of life to infection during World War II.
Antibiotics attack bacteria without harming cells belonging to the host organism. There are two
ways that antibiotics do this. Antibiotics like penicillin are called Bactericidals and kill bacteria by
inhibiting cell wall synthesis and thereby damaging the cell. Human and animal cells do not have
cell walls, so these antibiotics do not damage them. Erythromycin and tetracycline are
bacteriostatic antibiotics; they inhibit nuclei acid and protein synthesis. This type of antibiotic can
affect the patient receiving them, but because they have a greater effect on bacterial cells than
animal cells they can still be useful.
Related and Resource Websites
Center for Disease Control http://www.cdc.gov
PBS Evolution website, complete with web activities, video clips etc. is very informative
http://www.pbs.org/wgbh/evolution/
Activity
1. On the board have the following statement: “You stumble into the doctor’s office, sick as
a dog. You have a fever and stomach ache, as well as a runny nose. Your doctor
suggests that you take to your bed, drink lots of fluids, but doesn’t give you any
medication. You’re so mad you could spit. Why hasn’t the doctor given you any
antibiotics?” As students walk in they should respond to this statement in a written form.
2. Once you have given students enough time to respond to the statement ask them why
the doctor doesn’t provide any antibiotics. [Antibiotics are not effective treatment for a
virus infection.]
3. Ask students what antibiotics are used for. [Treating infections of bacteria] Do they know
who ‘discovered’ the first antibiotic? [Alexander Fleming]
4. Lead the students in a discussion about the discovery of penicillin by Alexander Fleming
and the impact that it had on disease. Explain that antibiotics act on bacteria by either
inhibiting cell wall synthesis or inhibiting protein synthesis thereby damaging the cells.
Ask students why this wouldn’t affect the host cells. [Human and animal cells do not
have cell walls and so are not impacted by the antibiotic. Antibiotics affect bacteria
protein synthesis at a much greater rate than human or animal protein synthesis.]
5. Review what type of pathogen is impacted by antibiotics. [bacteria]
6. Now present students with the table. In pairs or threes they should work on the table.
They are to imagine that as a doctor they are actively trying to avoid the over prescription
of antibiotics. The table lists multiple types of diseases, students should identify what the
nature of the illness is, what kind of pathogen is being considered, if any, and if an
antibiotic will work.
Illness
Strep throat
Measles
Chicken pox
Ear ache
Common cold
Cause (Pathogen name and
type if appropriate)
Antibiotics –Yes/No
AIDS
Allergies
“Mono”
7. Students should research each common illness and complete the table.
8. Once they have finished the table they are to suggest at least two other illnesses that
might be a little tricky for their peers to work out.
9. Once students have completed the chart you may wish to direct them to the impressive
PBS website on evolution: http://www.pbs.org/wgbh/evolution/survival/enemy/ or to the
CDC pamphlets on Antibiotic resistance:
http://www.cdc.gov/drugresistance/community/files/CDC_parents_brochure1.pdf
10. Students should review the talks or the pamphlet and summarize what the problem is and
why it has occurred. Have patients played a role in the problem? Why and how?
Embedded Assessment
1. The written statement at the beginning of class allows for a pre-assessment of students’
knowledge about antibiotic targets.
2. The chart allows students to explore a variety of common illnesses and identify whether
they can be treated with antibiotics.
Homework