Antibiotics

Antibiotics, such as penicillin, are drugs developed to cure infections caused by bacteria. Some antibiotics work by destroying the cell wall of the bacteria so that they can't replicate.

• **Antibiotics do not affect viruses - **Antibiotics do not destroy viruses because viruses stay inside host cells and are not living cells.
• **Antibiotics are specific - **Specific antibiotics are prescribed by medical doctors for specific diseases. The use of antibiotics has greatly reduced the number of deaths from infectious bacterial diseases.

Antibiotic Resistance

Some strains of bacteria are resistant to certain antibiotics. This means that these antibiotics cannot kill them. MRSA is often called a “superbug” because it is resistant to many antibiotics.

How to stop antibiotic resistance?

To help prevent strains of resistant bacteria from developing:

• Doctors should only prescribe antibiotics if they are needed and not for minor infections or viral infections.
• Patients should complete their course of antibiotics to ensure all bacteria are killed.

Bacteria can become resistant to antibiotics. This is the process:

1. Random mutations - Within a population of bacteria, some will have random mutations (random change in DNA). The mutated bacteria are resistant to antibiotics and so they are able to survive, whilst the non-resistant bacteria die.
2. Natural selection - The resistant bacteria can reproduce rapidly because their competition (the non-resistant bacteria) has been destroyed by the antibiotic. When the resistant bacteria reproduce, they produce genetically-identical copies. These copies will all be resistant to the antibiotics.

In a population of bacteria, a random mutation can arise, which makes that bacteria more resistant to antibiotics. The resistant bacteria reproduce asexually, so the copies will be genetically identical.