There are real dangers associated with bacteria evolving genes resistant to antibiotics as it then makes it much harder to treat those infections.

One example is tuberculosis or TB which is a bacterial lung disease. It was once a major cause of death within the UK but antibiotics succeeded in decreasing the death toll. However, recently TB bacteria have evolved resistance to the best antibiotics available at treating the infection making them multidrug resistant. Sufferers are now prescribed a combination of antibiotics which they have to take for six months. However, despite the best efforts of the drug companies, TB bacteria are evolving one step ahead of their efforts.

Another example of an antibiotic resistant bacteria is Methicillin-resistant Staphylococcus aureus or MRSA. This strain of Staphylococcus aureus has managed to evolve resistance to a number of the top antibiotics. In fact, some strains are actually resistant to basically all forms of antibiotics currently available. MRSA can cause only a minor skin infection but it can also lead to life threatening illnesses like septicaemia and meningitis. It can take a long time for a doctor to gauge which antibiotics, if any, are effective against a particular type and this may not be fast enough for some patients. As with TB, drug companies are working at developing different ways of dealing with this disease.