Medicines for bacteria only

The idea

Antibiotics are medicines that kill bacteria; they work only against bacterial infections because they target parts of bacterial cells unlike human or animal cells, and are ineffective against viruses or protozoa.

A visit to the doctor

If our immune system fails to protect us, we fall ill and visit a doctor. The doctor may give medicines called antibiotics.

Will an antibiotic help against an illness caused by a virus?

• Yes
• No
• Only a bigger dose will

Try the antibiotic

Choose an infection. Then give an antibiotic and see what happens.

Only against bacteria

Antibiotics are medicines that kill bacteria. They work only against bacterial infections because they target parts of bacterial cells that are different from human or other animal cells. They do not work against viruses or diseases caused by protozoa.

The first antibiotic, penicillin, was discovered in 1928 by Alexander Fleming. He noticed that a mould stopped bacteria from growing.

• Cause of the infection | Does an antibiotic work?
• Bacteria | Yes: it kills them
• Viruses | No
• Protozoa | No

Notes

Antibiotics kill bacteria. They work only against bacterial infections, because they target parts of bacterial cells unlike human or animal cells. They do not work against viruses or protozoa.

• Cause | Antibiotic works?
• Bacteria | Yes
• Viruses | No
• Protozoa | No

Check yourself

Antibiotics are medicines that kill...

A person has an infection caused by a virus. Will an antibiotic help?

Why do antibiotics work only on bacteria?

• bacteria — correct. Yes. Antibiotics kill bacteria.
• viruses. Antibiotics do not work against viruses.
• protozoa. Antibiotics do not work against diseases caused by protozoa.
• No. Antibiotics do not work against viruses — correct. Yes. They work only against bacterial infections.
• Yes. It kills all germs. Antibiotics kill bacteria only.
• Yes. It kills viruses first. Antibiotics do not work against viruses at all.
• They target parts of bacterial cells that are different from human or other animal cells — correct. Yes. That is why they work only against bacterial infections.
• They are made only for children. The reason is in the cells: they target parts of bacterial cells.
• They kill every kind of cell, so they are only used on bacteria. They target parts of bacterial cells that are different from human or other animal cells. They do not kill every kind of cell.