Natural Selection is defined as the process by which organism that are better adapted to their environment will survive and produce more offspring. Evolution is defined as the gradual development of something, from simple to a more complex form (Merriam-Webster dictionary).
These two processes together are responsible for why our once "miracle" medicines are no longer as effective after the introduction of antibiotics.
Antibiotic Resistance Evolution
Since the introduction of antibiotics, bacteria have evolved by natural selection adapting to become more suited for their environments. When treated with an antibiotic, the drug kills most of the bacteria, but the few surviving strands will survive to reproduce offspring also resistant to the antibiotic, eventually causing the an antibiotic resistant infection.
Causes of Antibiotic Resistance
Anitbiotic resistant bacteria can be born from the overperscription of antibiotics (Singh, 2012). Too often, patients are uninformed about the inability of antibiotics to treat viral infections. These patients then demand antibiotics from their doctors to treat their symptoms. Some doctors succumb to the requests of their patients and perscribe antibiotics when they are not needed, leading to the current trend in overperscritpion that is seen in the United States (Singh, 2012). Along these same lines, much of the public is unaware of the negative effects of high powered cleaning products used in households. These high powered antibacterial soaps set the stage for the evolution of "superbugs" which could adversly effect human health (Schorr, 2013).
Strategies to Combat Antibiotic Resistence
There are several campaigns that have been started to educate the general public on the problems associated with overperscription of antibiotics (See the "Get Smart" campaign offered by the CDC). The hope is that more knowledge about this topic will decrease the trend in overperscription. Drug over-kill is used through using a combination of strategies to kill all infectious agents so there are none to pass on resistance to future generations. Also, direct observation therapy has been used to ensure patients who are perscribed antibiotics finish their rounds of antibiotics, ensuring there is less of a chance the bacteria becomes resistant. Another strategy used is withholding the most powerful drugs until absolutely necessary. This helps make sure that bacteria are not coming in contact with the drug frequently, thus extending the usefulness of the drug (Palumbi, 2001).
Palumbi, S. 2001. Humans as the World's Greatest Evolutionary Force. Science, New Series, 293: 5536, 1786-1790.
Schorr, M. (2013, September 7). Antibacterial Soaps Concern Experts. Retrieved from http://abcnews.go.com/Health/story?id=117985
Singh, M. (2012, October 4). Despite Many Warnings, Antibiotics Are Still Overprescribed. Retrieved from http://www.npr.org/blogs/health/2013/10/04/229167826/despite-many-warnings-antibiotics-are-still-...
n.a. (2013, November 4). Get Smart: Know When Antibiotics Work. Retrieved from http://www.cdc.gov/getsmart/antibiotic-use/know-and-do.html