MRSA is the most prevalent type of hospital-acquired infection in England, which strike around 100,000 people each year and cost the NHS £1bn, accounting for 44% of cases. MRSA, which stands for methicillin-resistant staphylococcus aureus, is one of a family of staphylococcal bacteria.

It is estimated that between 20% and 40% of people in the UK carry MRSA, mostly in our noses or on our skin. So-called community-acquired MRSA (C-MRSA) is usually relatively harmless for the general population, although it can cause boils or other minor infections. However, patients in hospital tend to be older, sicker and weaker than the general population, making them more vulnerable to MRSA.

MRSA can cause significant infections in deep wounds, on medical devices such as artificial hip joints or heart valves, or if it gets into the bloodstream via intravenous catheters, particularly in severely ill patients, such as those undergoing chemotherapy. Bloodstream MRSA infections can lead to kidney, liver and heart failure.

The over-use of antibiotics is also blamed for the rising rates of infection. Over-reliance on the drugs has helped speed up the ability of germs to mutate for self-preservation. Many people ignore their doctor's advice to finish an entire course of antibiotics. This means that not all the bugs are killed off and the ones that survive are most likely to be drug resistant.