Genetic blueprint of MRSA cracked

Cracking MRSA's code could lead to new treatments

Scientists have hit back at hospital superbugs by cracking the genetic code of a common strain of MRSA.

The strain chosen causes a half of all the known UK outbreaks of MRSA.

The researchers from the Wellcome Trust Sanger Institute in Cambridgeshire hope they will be able to use the code to find weaknesses in MRSA.

The findings, published in Proceedings of the National Academy of Sciences, come at a time when scientists fear MRSA deaths could double in five years.

The strain of methicillin-resistant Staphylococcus aureus bacterium studied, called EMRSA-16, contains several unique genetic elements that are related to its virulence and drug resistance.

Dr Matt Holden and colleagues also looked at a "cousin" of the bacterium which is susceptible to antibiotics.

DNA swapping

Both showed evidence of movement and swapping of DNA with other organisms.

The researchers believe some of these DNA swaps might help MRSA to thrive in hospitals.

Dr Holden said: "This new atlas shows that the strain that is most prevalent in the UK is very different from previously sequenced superbugs.

The genome sequence and the light it sheds on evolution in MRSA gives us one more tool to understand how disease occurs and possibly to find new methods to combat these diseases Dr Sharon Peacock, honorary consultant in clinical microbiology at the John Radcliffe Hospital in Oxford

"It has evolved a 'Pick'n'Mix' genome that incorporates favoured genes that improve its resistance and ability to cause disease - genes that are vital to its spread and success."

Dr Julian Parkhill, project manager at the Wellcome Trust Sanger Institute, said: "MRSA and other pathogens are driven to acquire new tricks to evade or defeat the defences we put up.

"Our results clearly show that bacteria are capable of very rapid evolutionary change and remain a formidable enemy," he said.

Dr Sharon Peacock, honorary consultant in clinical microbiology at the John Radcliffe Hospital in Oxford, said: "The rise in hospital-acquired infections and the increase in resistance to antibiotics are major challenges to health service providers around the world.

"The genome sequence and the light it sheds on evolution in MRSA gives us one more tool to understand how disease occurs and possibly to find new methods to combat these diseases."