Question

How does antibiotic resistance develop when mutation was previously present, and drugs don't induce the resistance, but the environmental stress of the antibiotic drug affects that mutation?

Answer 1

Antibiotic resistance develops when pre-existing mutations allow bacteria to survive in the presence of antibiotics. The environmental stress of the antibiotic drug indirectly affects the pre-existing mutation by providing a selective advantage. The gene for resistance is already present in the bacterial gene pool at a low frequency.

Step-by-step explanation:

Antibiotic resistance develops when pre-existing mutations allow bacteria to survive in the presence of antibiotics. The gene for resistance is already present in the bacterial gene pool at a low frequency. When antibiotics are applied, they selectively kill bacteria without the resistance gene, leaving behind the resistant ones to survive and reproduce. The environmental stress of the antibiotic drug indirectly affects the pre-existing mutation by providing a selective advantage to bacteria with the resistance gene.