Evolution and Antibiotic Resistance

Evolution and Antibiotic resistance

Evolution is a "genetic change in a population or species over generations" (Simon, 2010). Antibiotic resistance is the ability of a microorganism to handle the effects of an antibiotic. A resistance is a consequence of evolution through natural selection which deals with random mutation. Natural selection is the "process in which organisms with certain inherited characteristics are more likely to survive and reproduce than other organisms with different characteristics" (Simon, 2010). Mutation is the "change in sequence of DNA, a source of genetic diversity" (Simon, 2010). The action of an antibiotic is an environmental pressure, the bacteria which has a mutation that allows them to survive which are the ones that live and are able to reproduce.

Evolutionary theory contributes a large role in medicine and an example of such theory is the evolution of antibiotic resistance in bacteria. As stated in an article I found, "Microbiologists are continuing to study the way bacteria evolves so this way we can determine how microbes respond to treatments and they can manage the evolution of vicious diseases" (Pryce 2000).

Bacteria can evolve resistance to antibiotics in different ways. Bacterial resistance to antibiotics can take one of three forms. The three forms are a change in the permeability of the cell membrane. This either prevents the antibiotic from going into the cell or it can cause it to be pumped out of the cell. The second form is the ability to inactivate the antibiotic. The final form is to acquire a mutation that clarifies the target of an antibiotic so it's no longer sensitive. The way that bacteria can acquire resistance to an antibiotic is by the rise in population of cells by mutation or by a process called Horizontal Genes Transfer. In this process genes can be exchanged between unrelated microbial species.

Once antibiotics are prone to bacteria, they evolve mechanisms that make them resistant. Once an antibiotic is used because of an infectious disease, some will die while the other ones that are resistant to the antibiotic will remain alive and reproduce more. Genetics plays an important role in evolution, especially when it comes to mutation because of DNA. The process of mutation influences evolution due to chance. Some bacteria become resistant to antibiotics by mutation in their DNA. By gaining mutated DNA, bacteria can become antibiotic resistant because they can switch DNA, unlike humans, who have one set of DNA.

Bacteria become resistant to antibiotics by natural selection. "In the presence of antibiotics, the process of natural selection will occur, favoring the survival and reproduction of the mutant bacteria" (Answers, 2011). Mutation and Natural selection help the bacteria population in becoming resistant to antibiotics.