The combination of both rapid growth rates and clever adaptation mechanisms make antibiotic resistance an issue that can arise quickly. Antibiotic resistance is when infectious bacteria adapt and become immune to the harmful effects of administered drugs.
Antibiotic resistant bacteria strains arise from adaptations that allow them to perform the processes the drugs target in a different way. This is a natural, survival-based phenomenon that occurs irrespective of antibiotic misuse, the largest cause of resistance. Nevertheless, increased exposure to antibiotics creates a higher chance of one bacterium evolving an advantageous trait that allows it to survive. This bacterium can then replicate, and all its offspring will now possess the survival adaptation.
In addition to this, bacteria can also help each other by trading their drug resistance with one another. While humans have their genetic material constrained within the nucleus of the cell, bacteria possess circular DNA pieces called plasmids. These can be transferred between both the same and different strains of bacteria, through a process called conjugation. For this to occur, two bacteria need to come together and allow for the exchange of plasmids. The new plasmids are treated as if they were a native part of their genetic make-up.