Misusing antibiotics is a problem that can be harmful to the individual and to society. explain why the proper use of antibiotics is so important?

 Antibiotics need to be used with caution because of evolution. If you treat bacteria with an antibiotic, some will be resistant by sheer chance. Those ones will survive and go on to divide - producing more antibiotic resistant bacteria. With medical antibiotics, they must be taken for the entire course. Even after symptoms have passed, bacteria remain in the body. If a patient stops taking antibiotics too early, the survivors can keep dividing and cause a new antibiotic resistant infection. With the normal course of medication, antibiotics kill off enough bacteria and keep them at bay long enough for the immune system to finish the job and take care of any resistant stragglers. 

The real danger, though, comes from antibiotic use in livestock. It's more cost effective to feed cattle with a constant supply of antibiotics, whether they're sick or not (as opposed to just treating them when they're sick). These antibiotics keep them from getting sick, but it means that eventually bacteria adapt to them and gain resistant. To make matters worse, the antibiotics are often passed from their bodies in their waste, which can go on to contaminate waterways. This can disrupt ecosystems and produce antibiotic-resistant bacteria in the wild. This type of usage is of much more concern because of its scale - there are far more cows on antibiotics than people