# Antibiotic resistance

When bacteria evolve so that an antibiotic no longer kills them.

Biology (school) · Part 04: Health and disease · Card 9 of 10 · Last updated 2026-10-19

## Analogy

A lock that changes so the old key no longer fits.

## In practice

MRSA is a bacterium resistant to many antibiotics and is hard to treat.

## Practice

### Flashcards

- **What causes antibiotic resistance to spread?** Overuse of antibiotics lets resistant bacteria survive and multiply.

### Interview questions

**Explain why antibiotic resistance is a problem and how it can be reduced.**

- Mutations make some bacteria resistant
- Antibiotics kill non-resistant bacteria so resistant ones multiply
- Infections become harder to treat
- Doctors should prescribe antibiotics only when needed and patients should finish courses

## Questions people ask

### How does antibiotic resistance develop?

Bacteria reproduce quickly, and random mutations can make one resistant to a drug. When the antibiotic kills the non-resistant bacteria, the resistant ones survive and multiply, passing on the resistance. This is natural selection, and it happens faster the more antibiotics are used.

### What can we do about antibiotic resistance?

Doctors should prescribe antibiotics only when necessary and not for viral infections. Farmers should use fewer antibiotics on healthy animals. Patients should follow instructions. Hospitals use hygiene to stop resistant bacteria spreading. Scientists are also working to develop new antibiotics.

## Related concepts

- [Antibiotic](https://studyvisually.com/learn/science/biology-school/biology-school-part-4/biology-school-part-4-concept-8)

Web page: https://studyvisually.com/learn/science/biology-school/biology-school-part-4/biology-school-part-4-concept-9
Study this card in the app: https://studyvisually.com/app/learn?category=biology-school&card=biology-school-part-4-concept-9