Question

Explain how using a combination of two antimicrobial drugs helps prevent the development of spontaneously resistant mutants?

1) All drugs work synergistically with each other. Their combined effects are far greater than either could achieve individually. Two drugs together helps to eliminate microbes, even if they have developed spontaneous mutations that would make them resistant to the drugs.
2) It is highly unlikely that the microbe might spontaneously develop two specific mutations to resist the effects of a pair of drugs. As such, even if one drug is resisted by the microbe, the second drug will eliminate the mutated microbe, thus preventing the development of spontaneously resistant mutants overall.
3) All drugs work antagonistically with each other. Their combined effects are far greater than either could achieve individually. Two drugs together helps to eliminate microbes, even if they have developed spontaneous mutations that would make them resistant to the drugs.
4) Drugs can also select for mutations that will enhance the activity of another drug. Therefore, each of the paired drugs will help to select for spontaneous mutations that enhance the activity of the other drug in the pair.
5) Bacteria can only ever develop resistance to a single antibiotic. If more than one drug is used, the organisms will definitely become resistant to one of them but it will not become resistant to both of them. The second antibiotic will kill the organism.

Answer 1

Using a combination of two antimicrobial drugs helps prevent the development of spontaneously resistant mutants by their synergistic effects, preventing the development of multiple specific mutations, and selecting for enhanced activity.

Step-by-step explanation:

Using a combination of two antimicrobial drugs can help prevent the development of spontaneously resistant mutants in several ways:

1. Synergistic effects: When two drugs work synergistically, their combined effects are greater than what they can achieve individually. This means that even if a microbe has developed spontaneous mutations that would make it resistant to one drug, the second drug can still eliminate the microbe.
2. Unlikely development of multiple specific mutations: It is highly unlikely that a microbe would spontaneously develop two specific mutations to resist the effects of a pair of drugs. So even if one drug is resisted by the microbe, the second drug can still eliminate the mutated microbe, preventing the development of spontaneously resistant mutants overall.
3. Selection for enhanced activity: Sometimes, the use of two drugs can select for mutations that enhance the activity of the other drug. Each of the paired drugs can help select for spontaneous mutations that enhance the activity of the other drug in the pair.