Overuse and misuse of antibiotics leads to increased occurrences of antibiotic resistant bacteria. We have an infestation of some mutant bug, a spider-cockroach hybrid that isn’t afraid to charge at us when we try to kill it. So, we call a professional to exterminate the hybrid monster bugs. The exterminator uses a substance that kills 95% of the spider-cockroach mutants but leaves 5% not killed. Now imagine, not only are these hybrid bugs not dead but they are now stronger. They have been exposed to the substance that killed the other 95% and have evolved to defend against that lethal substance. In addition, they are multiplying and passing their enhanced defense against the killing substance to their young. Antibiotics are designed to treat bacterial infection. Not unlike the substance used by the exterminator. They attack bacteria within the body by either killing the bacteria or stopping the bacteria from multiplying. Antibiotics are meant to be used as a last line of defense. The human body can usually stop an excess of harmful bacteria from multiplying without the use of antibiotics however, there are instances when the bacteria becomes too great for a healthy immune system, this is when antibiotics are effective.
Antibiotics are only effective when prescriptions are followed through. A doctor will prescribe a specific number of pills to rid the body of the infection. If we fail to follow though and take all the pills, then the above analogy proves true. We will have exposed some bacteria to the drug meant to destroy them but not enough to kill them. Now exposed, those bacteria grow stronger. They will no longer be killed by the antibiotic first prescribed. Thus, this misuse of antibiotics increases the likelihood of an antibiotic resistant bacteria.
The use of antibiotics in animal agriculture is also contributing to resistant bacteria. Most of the meat found at the local grocer is contaminated with antibiotics. The farmers we buy our meat from are using these antibiotics to increase their profits. Antibiotics both aid in weight gain of their livestock, giving them more inventory, and keeps their livestock healthier, giving them more inventory. The situation: animals take antibiotics, whether needed or not, increasing the likelihood of developing resistant bacteria, we eat the animals containing resistant bacteria resulting in the introduction of that resistant bacteria to our system. The microbial ecosystem of the animals we eat is interwoven in such a way that it is unable to be separated from our own. This makes this passing of resistant bacteria impossible to negate unless we were to not feed livestock antibiotics.
https://mmbr.asm.org/content/74/3/417.full#sec-16
https://www.medicalnewstoday.com/articles/10278.php
Counterintuitive 