SuperbugsMRSA superbug spreads from big city hospitals to regional health centers

Published 15 May 2012

MRSA — methicillin-resistant Staphylococcus aureus — first started to appear around fifty years ago following the introduction of antibiotics, to which the bacteria has become increasingly resistant; scientists now find how the superbug spreads among different hospitals

Hospitals in large cities act as breeding grounds for the superbug MRSA prior to it spreading to smaller hospitals, a study suggests.

Researchers found evidence that shows for the first time how the superbug spreads among different hospitals throughout the country. The University of Edinburgh study involved looking at the genetic make-up of more than eighty variants of a major clone of MRSA found in hospitals.

Scientists were able to determine the entire genetic code of MRSA bacteria taken from infected patients. They then identified mutations in the bug which led to the emergence of new MRSA variants and traced their spread around the country

A University of Edinburgh release quotes Dr. Ross Fitzgerald, of the Roslin Institute at the University of Edinburgh, who led the study, to say: “We found that variants of MRSA circulating in regional hospitals probably originated in large city hospitals. 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.”

MRSA — methicillin-resistant Staphylococcus aureus — first started to appear around fifty years ago following the introduction of antibiotics, to which the bacteria has become increasingly resistant.

Paul McAdam, of the Roslin Institute and first author of the paper, said: “Our findings suggest that the referral of patients to different hospitals is a major cause of MRSA transmission around the country. This knowledge could help in finding ways to prevent the spread of infections.”

The paper, published in the journal PNAS, also found that the MRSA strain studied evolved from antibiotic-sensitive bacteria that existed more than 100 years ago.

— Read more in Paul R. McAdam et al., “Molecular tracing of the emergence, adaptation, and transmission of hospital-associated methicillin-resistant Staphylococcus aureus,” Proceedings of the National Academy of Sciences (14 May 2012) (doi: 10.1073/pnas.1202869109)