In short and quoting:
Resistant bacteria were identified by the presence of a gene which codes for antibiotic resistance.The bacteria (the ones that are able to at least, and there's a bunch of them!) can adapt to the "harsh" effects of an antibiotic, making themselves resistant, therefore surviving. This farmacological misuse should be stopped by educating the greater public that antibiotics aren't the solution to every disease. A continuous misuse of antibiotics should be handled with great care, since it can lead to killing the natural flora in several parts of our body, mainly the gut flora, such as Escherichia coli.
In children who did not receive an antibiotic, there was no increase in the proportion carrying resistant bacteria in the throat from the initial level at 2 or 12 weeks.
However, in children who received an antibiotic, the number carrying resistant bacteria more than doubled at the two week follow-up, but fell back close to the initial level by 12 weeks.