SCIENTISTS have discovered a genetic variation that can make people twice as likely to survive severe infections such as pneumonia and MRSA.

The survivor gene, as it has been dubbed, has been discovered by doctors and researchers studying the genetic make-up of 150 intensive care patients and monitoring their survival rates.

Researchers at Newcastle University, working with doctors at the city's Royal Victoria Infirmary, found a variation in mitochondrial DNA in human cells leads to much higher survival rates.

About 40 per cent of the UK population has the survivor gene, which is inherited from each person's mother.

Experts say the findings could lead to screening of patients and new treatments, which are becoming increasingly important because of antibiotic-resistant diseases such as MRSA.

Each of the 150 patients who was monitored gave a blood sample so their DNA make-up could be determined.

The survival rate was then worked out for each variation of mitochondria.

In total, ten types of mitochondria were found, with the most common group - Haplogroup H - having the best survival rates

Professor Patrick Chinnery, who led the research with Dr Simon Baudouin, said: "Despite all the advances in modern medicine, the chance of people dying when they go to intensive care is still around 40 per cent.

"But this type of mitochondria makes you twice as likely to survive for six months after leaving intensive care. In medical terms, that is colossal."

The survivor gene was successful in increasing resistance to a range of infections, rather than just being able to fight a particular disease.

That resilience is likely to become important due to Britain's ageing population, which is becoming more susceptible to serious infections.

The findings were published in The Lancet medical journal.