The establishment of antibiotics almost ninety years ago with the creation of penicillin completely changed the impact of bacterial infections, making some previously fatal ailments into nothing more than brief illnesses that gave people several days of discomfort. These drugs are miraculous in this way, but the more they are used and exposed to bacteria, the more resistant bacteria can become to them. Antimicrobial resistance results from the overuse of antibiotics to treat illnesses and antibiotic use in agriculture for different purposes.
Bacteria become resistant to different antibiotics simply from continuous exposure to them due to natural selection. Biological evolution is something that is often thought of only occurring over a significant period of time, but it actually happens before our very eyes every day, just in organisms that are so small that we cannot even see them. In the simplest sense, natural selection takes place when an individual or a group within a species attains a trait through a genetic mutation at birth that makes it or them better suited for their environment than other members of their species, or even among other species. An example of this is the evolution of the polar bear, in which an individual or several brown bears were born with white fur in the arctic, giving them a distinct advantage while hunting seals that led to the local extinction of brown bears who had difficulties capturing food. As an isolated group, these bears developed more mutations over time until they became a distinct species.
In complex organisms, natural selection can take some time, but many minor changes still occur in the parts of the body that interact the most with stimuli, such as the teeth, fingers, and toes. However, due to their size, simple organisms are forced to interact with environmental stimuli with all of their body. With the case of introducing antibiotics into their colony, we are controlling their environment. Natural selection is accelerated in bacteria even without this process, since these organisms die and reproduce at such a rapid rate, allowing different mutations to occur that can then become the genetic norm throughout the colony. While using antibiotics kills these bacteria, it increases the possibility for a single cell to arise through microevolution that is resistant to the antibiotic used, which can then replicate this quality to its descendants.
One of the key reasons that have led to antimicrobial resistance is the misuse or overuse of antibiotics. Along with their use to treat bacterial infections, antibiotics are often used or prescribed for problems that they cannot solve, such as infections caused by viruses. This can then promote antibiotic-resistant materials into the bacteria that do not cause the ailment being treated, which can then be passed on to the bacteria that the antibiotics would otherwise prevent.
The problem of antimicrobial resistance is not entirely from continuous use on humans; it also derives from applications on livestock in agriculture. Farmers use antibiotics to treat different bacterial issues in livestock, but they have also used them in incredibly excessive amounts. Eighty percent of all antibiotics sold in the United States are for use in livestock and poultry, and farmers have made a habit of putting them into livestock feed of perfectly healthy animals to prevent any kind of disease. Additionally, antibiotics have been used in aquaculture and around crops. Using this much of this medicine greatly allows for the birth of resistant bacteria, which is then present throughout the surrounding environment of the farmlands and even on the food products that we consume.
Interestingly, resistance to antibiotics has actually derived from the existence from antibiotics themselves. Throughout the majority of human history, the population of the world has remained relatively low, and was only 1.65 billion people in the year 1900. However, from the innovations in science and medicine in the early Twentieth Century, the human lifespan has greatly expanded, with the current world population estimated at 7.3 billion. Antibiotics are one of the primary medical accomplishments that have encouraged population growth by keeping people alive. Obviously, as the result of people living longer, the population of the Earth has grown and more people require antibiotics. In addition, a swelling population has a greater need for food, which has led to an increase in livestock, along with more efficient methods of meat and produce production. One of the failures of these efficient methods has been excessive use of antibiotics to prevent illnesses in the animals.
According the WHO, antimicrobial resistance is a complex problem driven by many interconnected factors, and it can only be resolved properly if each related party takes action. Public policy is a huge part of this, since it can set regulations on the source of resistance, such as with farms and their livestock. The farmers themselves should try to use antibiotics when they are needed, but only under veterinary supervision. For individuals, it is necessary to maintain general good health, mainly keeping up-to-date with vaccinations and avoiding those that you know are sick. Additionally, people should not misuse their antibiotic prescriptions, and should never give any left over to somebody else. Doctors, like the public, should correctly use these drugs and only prescribe them when they are necessary to cure their patient.
Even though all of these efforts can help to reduce the amount of resistance that is built to antibiotics in the future, we cannot change the bacterial evolution that has occurred in the past. The solution to this is the pharmaceutical industry, in which newer antibiotics should be devised that bacteria have not became resistant to or are less prone to develop any amount of resistance. For example, a new antibiotic, Teixobactin, kills pathogens without detectable resistance being developed by bacteria in response to it. Developments like this can help to ensure that the process of antimicrobial resistance from the past is not repeated in the future.