Irish scientists have identified a major increase in new strains of the superbug MRSA, which are more likely to be found in the community.

MRSA (Methicillin-Resistant Staphylococcus Aureus) is a form of the bacteria, Staphylococcus aureus, which has become resistant to standard antibiotics - including the antibiotic methicillin. It is often referred to as a ‘superbug' due to its ability to resist treatment.

MRSA is most commonly associated with hospital patients, particularly older and more vulnerable patients.

However, these new strains - PVL-positive MRSA - are more likely to be found among younger people in the community. The PVL (Panton-Valentine leukocidin) toxin can increase the ability of Staphylococcus Aureus to cause disease via the destruction of white blood cells and damage to the body's soft tissues and skin.

An analysis by microbiologists at the Dental School in Trinity College Dublin (TCD) revealed that between 2002 and 2011 in Ireland, there were big increases in the prevalence and genetic diversity of these PVL-positive strains.

The TCD scientists are working in collaboration with the National MRSA Reference Laboratory at St James's Hospital in Dublin and Alere Technologies in Germany.

They found that among MRSA samples provided to the MRSA reference laboratory, there was a 44-fold increase in the prevalence of PVL-positive MRSA. There was also a six-fold increase in the number of PVL-positive samples that were found to be resistant to multiple antibiotics.

Commenting on the findings, Prof David Coleman of TCD described this as a ‘worrying development'.

"Enhanced surveillance in both hospitals and communities is vital to ensure that these strains do not spread and become more established," he said.

Using the latest technology, the scientists were able to identify ‘an unprecedented level of genetic diversity' among these PVL-positive strains.

"This diverse range of PVL-positive MRSA strains circulating appears to have increased in recent years and international travel is likely to have been a significant contributory factor," TCD said.

Details of the scientists' findings are published in The Journal of Clinical Microbiology.