Resistant germs
Show on a big screenAn antibiotic that worked once may stop working. How can that be?
Bacteria multiply: each one divides in two, again and again.
Bacteria are not all alike. A few may survive an antibiotic. Those are resistant to it.
- A crowd of bacteria. Two are resistant.
- The antibiotic acts on the other ten.
- The two survivors multiply.
- Use after use, resistant ones fill the crowd.
Survivors resist it and multiply. After many uses, most bacteria resist it.
The rule
Some bacteria survive an antibiotic and multiply. These are resistant bacteria. Resistant bacteria can spread. Each use of an antibiotic leaves them behind. Using one when it is not needed gives them more chances. The bacteria are resistant, not the person.
| An antibiotic is used | Chances for resistant bacteria |
|---|---|
| Only when a doctor says it is needed | Fewer |
| When it is not needed | More |
Only a doctor decides who needs an antibiotic, and for how long. The numbers here are made up. A real worry goes to a parent, a teacher or a doctor.
Slide the number of uses. Watch the crowd.
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