A bacterium is found that is resistant to the antibiotic gentamicin.The bacterium was isolated in a hospital where patients were routinely given gentamicin for a variety of infections.What was the pressure that selected for this resistant population?
A) Presence of gentamicin in the environment.
B) High mutation rate for the bacterium.
C) Growth situation for the bacterium.
D) Patients not receiving antibiotic provided source of bacteria.
E) Tainted food.

Question

Quizplus · Accepted Answer

The presence of gentamicin in the hospital environment created a selective pressure for bacteria that were resistant to the antibiotic. As a result, bacteria that were not resistant to gentamicin were eliminated or had reduced fitness, leaving behind a population of bacteria that were able to survive and reproduce in the presence of gentamicin. This is an example of natural selection at work.

A Bacterium Is Found That Is Resistant to the Antibiotic