Fears over new strain of MRSA bug

THERE are fears that a new form of the MRSA superbug discovered in two Irish hospitals could share its genetic information with a more virulent strain.

Professor David Coleman of Trinity College Dublin, who led the international team that identified the bacterium, said it was totally different from other types discovered throughout the world.

While a test had been developed to detect the organism that was not particularly resistant to antibiotics, it could cause problems in the future.

“These strains tend to share genetic information — they pass it around, and it is quite possible that this new MRSA could transfer its methicillin resistance into a more virulent strain. If that happened, then there could be problems,” he said.

Prof Coleman said the organism discovered in patients in a Dublin hospital and a hospital in the south did not develop in humans.

“It developed, more than likely, in an animal population. We don’t know what that animal population is yet,” he said.

MRSA (Methicillin resistant Staphylococcus aureus) is a bacterium, first described in the 1960s, that is responsible for several difficult to treat infections in humans because of its strong resistance to antibiotics.

Prof Coleman said the new strain transferred simultaneously into the human population in Ireland, Britain and Germany very recently. “It is very likely that this has happened before but was not picked up,” he pointed out.

“The organism is so different that it would not be detected by routinely-used genetic tests for screening patients for MRSA,” he said.

Prof Coleman said they picked up the MRSA as a result of working very closely with the national MRSA reference laboratory and hospitals would now be warned to look out for the organism.

“I have worked on MRSA for 25 years and we use high throughput screening systems which are very sensitive and DNA microarray tests that look at the entire genetic structure of the organism,” he said.

Prof Coleman said the research team at Trinity’s School of Dental Science took a closer look at two isolates by the laboratory because they looked peculiar. “When we screened them we knew we were looking at something different,” he said.

The team sequenced the entire genome and when they examined the DNA sequence they found it was completely different to all known MRSA types.

During the publication process they became aware that British scientists had made a similar finding.