There may be a danger, though, in underdosage. It is not difficult to make microbes resistant to penicillin in the laboratory by exposing them to concentrations not sufficient to kill them, and the same thing has occasionally happened in the body .
-Alexander Fleming (1945)
For those that do not know, Alexander Fleming is the founder of Penicillin – an antibiotic frequently used to treat bacterial infections. Antibiotics are the reason humans' lifespan has increased by decades since the 1940s. They save more than 200,000 American lives each year (2005). Fleming noted in 1945, the ignorant use of antibiotics could lead to the eventual resistance of them. Now in 2016, more and more cases of antibiotic resistant bacteria are showing up all over the world. In the United States alone, more than 2 million people become infected with microbes that are resistant to antibiotics (2013). Though there are a variety of reasons as to how they become resistant in the first place (i.e. doctors prescribing antibiotics for a non-bacterial infection, folks who don't finish their complete dosage of antibiotics, etc.), there is one that particularly stands out: Animal feed.
Antibiotics used in animal feed is a largely unaddressed issue. Farmers claim it's to keep animals healthy and free of infectious diseases. However, it's no secret they are almost always used for production purposes. For example, antibiotics assist the animals in growing faster and larger. If these antibiotics are abused in livestock, like Fleming said in humans, can't the same resistant result occur? The answer is of course! What some do not realize, however, is these antibiotic resistant microbes could spread to humans by eating that same meat found in your local grocery store. Thus, making humans resistant.
Unfortunately, antibiotics are sold four times as much to livestock than to fight actual human illnesses (Food Microbiology: In Human Health and Disease). Pharmaceutical companies are often more concerned with profit in livestock rather than developing antibiotics that bacteria aren't resistant to. In order to make any change in the animal industry, it's important to do research and be cautious of the food you buy. Who provides antibiotic free meat? How can one prevent getting infected in the first place? What's the perfect temperature for cooked meat? If enough people are not buying meat that are fed antibiotics, the corporation will eventually go bankrupt. On that note, check out the Centers for Disease Control and Prevention's website on monitoring antibiotic resistant bacteria: http://www.cdc.gov/narms/animals.html