Resistant bacteria

Bacteria can evolve rapidly because they reproduce at a fast rate.

Mutations of bacterial pathogens produce new strains. Some strains might be resistant to antibiotics, and so are not killed. They survive and reproduce, so the population of the resistant strain rises. The resistant strain will then spread because people are not immune to it and there is no effective treatment.

MRSA is resistant to antibiotics.

To reduce the rate of development of antibiotic resistant strains:

• doctors should not prescribe antibiotics inappropriately, such as treating non-serious or viral infections
• patients should complete their course of antibiotics so all bacteria are killed and none survive to mutate and form resistant strains
• the agricultural use of antibiotics should be restricted.

The development of new antibiotics is costly and slow. It is unlikely to keep up with the emergence of new resistant strains.

There are links with this content to Antibiotics and painkillers (page 37).