British scientists trace spread of superbug through healthcare system

A new study from Great Britain suggests that hospitals in large cities may be acting as breeding grounds for the superbug methicillin-resistant Staphylococcus aureus before spreading it to smaller hospitals.

The researchers have evidence that demonstrates for the first time how MSRA bacteria may be spreading in the U.K. through the healthcare system, according to

The investigation, conducted by scientists at the University of Edinburgh, examined the genetic structure of more than 80 variants of a major clone of MSRA that has been found in hospitals. The researchers were able to determine the genetic code of MSRA bacteria that had been taken from hospital patients.

Once the entire code was identified, the team looked at mutations that led to new variants of the bacteria that could then be traced as they spread to various locations.

"We found that variants of MRSA circulating in regional hospitals probably originated in large city hospitals," Dr. Ross Fitzgerald of The Roslin Institute of the University of Edinburgh said, said. "The high levels of patient traffic in large hospitals means they act as a hub for transmission between patients, who may then be transferred or treated in regional hospitals."

The study, published in the journal PNAS, also traced back the origin of the MSRA strain used for the research over 100 years to an antibiotic-sensitive bacteria. MRSA appeared approximately 50 years ago after the introduction of antibiotics.