Antibiotic resistance means that bacteria are unaffected by antibiotics. Bacteria have the ability to adapt quickly to their environment. Although this is a natural process, it also means they can get used to antibiotics and become resistant to them. The antibiotics then lose their effectiveness as a medicine. This unwanted adaptation process is helped and speeded up if antibiotics are used too often or wrongly.
So it is not people or animals that become resistant to antibiotics, but the bacteria. The resistant microbes are able to multiply very rapidly and can actually pass the resistance on to other bacteria. Since bacteria occur almost everywhere, they are easily transferred from one human being to another, or from an animal to a human and vice versa. If resistant bacteria cause a disease in humans or animals, it can be difficult or impossible to treat. In the worst-case scenario, it may even lead to death.