Bacteria can evolve quickly because they reproduce at a fast rate. Mutations in the DNA of bacteria can produce new characteristics. A random mutation might cause some bacteria to become resistant to certain antibiotics, such as penicillin. Antibiotics usually kill bacteria, but in this case the mutation means the bacteria cannot be destroyed by the antibiotic. This evolution of antibiotic resistance in bacteria is an example of natural selection leading to evolution.
The main steps in the development of antibiotic resistance in bacteria are:
The number of resistant strains has increased, partly due to the misuse of antibiotics. This has resulted in more bacterial infections that are difficult to control.
MRSA is methicillin-resistant Staphylococcus aureus. It is a very dangerous bacteria because it is resistant to most antibiotics and so if someone gets infected with MRSA they cannot be treated easily.
In order to reduce the rate of development of antibiotic resistant strains:
Penicillin was the first antibiotic to be produced on a mass scale in the 1940s. It is derived from Penicillium fungi, shown here growing on an agar plate.
Many new types of antibiotics were discovered during the 1950s and 1960s, but more recently, this has slowed greatly. Many scientists even stopped looking for new antibiotics, as they felt it was unnecessary.
Recent concerns of increasing antibiotic resistance have created the need for new antibiotics. However, this development is costly and takes a long time. Some scientists fear that we are fighting a losing battle against antibiotic resistant bacteria, which may ultimately lead to people dying from simple infections, for example, following an operation.