Which of the following best explains how a 'superbug' is created in a microbial population?

• A. By exposing bacteria to ultraviolet light, causing them to mutate into more virulent forms.
• B. Through the direct genetic engineering of bacteria to increase their pathogenicity.
• C. By mixing different species of bacteria together in a laboratory setting.
• D. Through the overuse and misuse of antibiotics, which select for resistant strains via natural selection.

Answer: (D)

Verified step by step guidance

1. Understand the concept of a 'superbug': it refers to bacteria that have developed resistance to multiple antibiotics, making infections difficult to treat.
2. Recognize that antibiotic resistance arises primarily through natural selection, where bacteria with mutations that confer resistance survive antibiotic exposure and reproduce.
3. Identify that overuse and misuse of antibiotics create selective pressure, killing susceptible bacteria but allowing resistant ones to thrive and multiply.
4. Note that other options like UV light causing mutations or genetic engineering are not the main natural mechanisms by which superbugs commonly arise in microbial populations.
5. Conclude that the best explanation for the creation of superbugs is the overuse and misuse of antibiotics leading to the selection of resistant bacterial strains.