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Headnote

MRSA has become a key election issue. But what is the truth behind the headlines? Biomedical scientist George Winter explains

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SUMMARY

This article explains what methicillin-resistant Staphy/ococcus aureus (MRSA) is, how it is spread and what the real challenges are in healthcare settings in the UK. It explores the different strains of MRSA and points out the main ways to control their spread. It is intended to be a reference source for all nurses.

Keywords

Methicillin-resistant Staphy/ococcus aureus * MRSA * Antibiotic resistance * Handwashing * Infection rates

Every year about 10 per cent of hospital patients develop a healthcare-associated infection (HAI). Such infections account for an estimated 5,000 deaths and cost the NHS £1 billion annually. Around 20 per cent of these deaths are blamed on the so-called 'superbug' methicillin-resistant Staphylococcus aureus (MRSA). But how much of a threat is it really?

S. aureus is a common bacterium. It is carried by around 30 per cent of healthy people and is found in the nose and in other moist and hairy areas of the body. S. aureus can cause not only relatively minor skin and soft tissue infections but also systemic infections such as abscesses, pneumonia, osteomyelitis and meningitis.

MRSA is the term for bacteria that have acquired resistance to the methicillin antibiotic. This means that although they are thought to be no more infectious to humans than antibiotic-sensitive S. aureus, the options for treatment of MRSA infections are more limited.

MRSA came to public attention in the 1980s when the first epidemic strain, EMRSA, was recognised in the UK. Since then a further 16 strains have been identified, each with a different genetic make-up and some with an extra resistance to antibiotics other than methicillin.

For example, EMRSA-15 is resistant to ciprofloxacin and sometimes erythromycin, and EMRS A-16 is resistant to ciprofloxacin, erythromycin and sometimes aminoglycosides. Currently EMRS A-15 and EMRSA-16 account for 96 per cent of all MRSA bloodstream infections in the UK.

The most recent strain, EMRSA-17, was isolated in 2000. Its emergence is worrying, since it is more resistant than any previous strains. As well as matching previous levels of resistance, EMRSA-17 is...

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