MRSA (methicillin-resistant Staphylococcus aureus) is a highly contagious strain of the Staphylococcus aureus family of bacteria. MRSA can exist harmlessly on people’s skins without their even knowing it, but if it infects someone who is already ill or weak, it can kill. Infections occur where there is opportunity for MRSA to get into the body, such as at surgical wounds or where a catheter or needle is inserted. The reason that MRSA is such a problem for hospitals and care homes – and why it has become known as a ‘superbug’ – is that it has developed resistance to methicillin and other antibiotics, so infections are much more difficult to treat.

This unit contains four possible activities. Each activity can be carried out independently of the others, using the same introduction to set a context. The first activity, ‘MRSA in the news’, and the timeline exercise in ‘Comparing the antibacterial properties of metals’ could be set as homework prior to the lesson.