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Q1.
Colistin is an antibiotic used to treat infections in the bloodstream.
Some bacteria are resistant to Colistin.
Explain how these bacteria have become resistant to Colistin.
(4)
When people do not finish their course of antibiotics, such as Colistin, not all the bacteria are killed. Some bacteria are left behind, especially the ones that are more resistant to the drug. This is similar to overusing or repeatedly using antibiotics, which gives bacteria more chances to adapt.
Some of these bacteria may have a mutation or a genetic variation. This means that they are slightly different from other bacteria and might have a gene or allele that makes them resistant to the antibiotic.
Because of this mutation, these resistant bacteria are more likely to survive when the antibiotic is used. The non-resistant bacteria die, but the resistant ones stay alive.
These resistant bacteria then reproduce and pass on their resistance to their offspring. Over time, more and more of the bacteria population become resistant. This is an example of natural selection or evolution, where only the fittest bacteria survive and reproduce.
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