Resistant bacteriaSpec 4.6.3.7
Bacteria can evolve rapidly because they reproduce at a fast rate. Mutations of bacterial pathogens produce new strains.
- A mutation produces a strain that is resistant to antibiotics.
- When antibiotics are used, non-resistant bacteria are killed. The resistant bacteria are not killed.
- The resistant bacteria survive and reproduce, so the population of the resistant strain rises.
- The resistant strain spreads, because people are not immune to it and there is no effective treatment.
MRSA is resistant to antibiotics.
Reducing the rate of development of resistant strains
- Doctors should not prescribe antibiotics inappropriately, such as for 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.
Quick check
Triple only Give two reasons why Darwin's theory was only gradually accepted.
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Any two of: it challenged the idea that God made all animals and plants; there was insufficient evidence; the mechanism of inheritance was not known.
Triple only Who published joint writings with Darwin in 1858?
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Alfred Russel Wallace.
Why is the fossil record incomplete?
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Early life was soft-bodied and left few traces, and many traces were destroyed by geological activity.
Why do resistant strains of bacteria spread so quickly?
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Bacteria reproduce quickly, people are not immune and there is no effective treatment.
Give one way to reduce the development of antibiotic resistance.
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Do not prescribe antibiotics inappropriately, complete the course, or restrict agricultural use.