New strains of superbug can kill in 24 hours

Highly virulent strains of the superbug MRSA which infect healthy young people with no connection to hospitals are appearing in the UK.

The new varieties cause skin and soft tissue infections such as boils, abscesses and inflammation and, in rare cases so far only seen in other countries, a severe pneumonia that can kill in 24 hours.

Since last April, dozens of Community-Acquired MRSA (CA-MRSA) cases have been identified by the Staphylococcus Reference Laboratory of the Health Protection Agency.

Healthy children seem to be most susceptible to this infection, as opposed to older people with weak immune systems who more commonly succumb to the strains found in Britain's hospitals.

Until now Britain had appeared untouched by CA-MRSA, which is distinct from the healthcare-associated strain. It is causing public health concern worldwide, particularly in the United States, where it has swept through prisons, military units and sports teams. It is spread by skin-to-skin contact, especially between people sharing towels or playing sports which can cause skin abrasion, such as American football or rugby. It has also been spreading among homosexual men in San Francisco. In some areas of the US, it now accounts for more than 70 per cent of MRSA cases reported.

'The kind of boils it can cause are not your average adolescent skin pimples, that's for sure,' said Angela Kearns, head of the Staphylococcus Reference Laboratory at the Health Protection Agency in north London. 'They can be quite severe infections which may need hospitalisation and drainage.'

But she emphasised that these infections are still rare: 'It's a watch-and-wait situation. Doctors are sending us isolated examples they are taking from infections that are not responding to the usual treatments.

'These are not, so far, what you might call the "epidemic" types of community strains which are infecting larger groups of people in the United States. In a handful of cases we have seen them passed between members of the same family. We're also seeing specific types infecting people who inject drugs.'

Although it is resistant to the penicillin class of antibiotics, unlike the hospital strains, CA-MRSA is not multi-drug resistant and treatment is straightforward in the majority of cases. Problems arise when doctors try to treat the skin infections using common penicillin drugs such as methicillin. The infection is then able to gain more of a foothold and can spread through the body.

Many MRSA experts now think it is inevitable that Britain will mirror the situation in America. 'MRSA is becoming a significant danger outside healthcare settings and it's spreading fast,' said Mark Enright of the University of Bath, who is working on several international studies of the origins and epidemiology of CA-MRSA.

'Some of these strains now produce a toxin that enables the bacterium to cause serious disease in healthy children and young adults.'

Outbreaks of CA-MRSA were first reported in the early 1980s, but it was not until the late 1990s that cases began to increase rapidly worldwide. Infections have been documented in countries including France, Denmark - where cases have more than doubled in the past two years - Switzerland, Saudi Arabia, India, Australia and New Zealand.