Bacterial drug resistance is becoming a problem in hospitals worldwide. "Superbugs" like MRSA and C. difficile are very difficult to treat and are showing up more and more in the human population. Many scientists believe that overuse of antibacterial medications has led to the
speedy evolution of these drug-resistant bacteria.
These drug-resistant bacteria become more common in the population through a series of steps. Number the steps from first to last.
= Drug-resistant bacteria build a large population in the host.
= A single bacterium develops a resistance to the drug due to a random genetic mutation.
= The host transmits the drug-resistant bacteria to the outside world.
= An antibacterial drug is used to treat an infection which kills off many honresistant bacteria.