Question

If the bacterium Staphylococcus aureus experiences a cost for maintaining one or more antibiotic-resistance genes, then what should happen in environments from which antibiotics are missing?
A) These genes should continue to be maintained in case the antibiotics ever appear.B) These bacteria should be outcompeted and replaced by bacteria that have lost these genes.C) The bacteria should try to make the cost worthwhile by locating, and migrating to, microenvironments where traces of antibiotics are present.D) The bacteria should start making and secreting their own antibiotics.

Answer 1

Answer:

The correct answer is B) These bacteria should be outcompeted and replaced by bacteria that have lost these genes.

Explanation:

If a bacteria experience a cost of maintaining some antibiotic-resistant gene, then they will able to flourish more in that environment which contains the antibiotic against which the antibiotic-resistant gene is present in the bacteria.

But if this bacteria is grown in medium that lack antibiotic then this bacteria will be outcompeted replaced by those bacteria who have lost these genes because these new bacteria are more adapted to this condition than the antibiotic-resistant bacteria. Therefore the correct answer is B.