If a Staphylococcus aureus biofilm encounters a sub-lethal dose of antibiotic, which consequence is most likely regarding antibiotic resistance?

💡 Explanation

Sub-lethal antibiotic exposure doesn't kill the bacteria outright, but rather it creates selective pressure. This favors bacteria with pre-existing mutations that enhance efflux pump activity or lead to increased mutation rates, because they can survive better in the presence of the drug. Therefore, antibiotic resistance increases, rather than reducing efflux or permeability.

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