MRSA superbug "Achilles heel" found

UK scientists have identified an "Achilles heel" gene that may help the MRSA superbug survive antibiotic treatment.

They say the discovery could help in the development of future drugs to overcome MRSA’s defence systems.

The latest statistics for 2009 show there were 781 deaths in the UK involving Methicillin-resistant staphylococcus aureus (MRSA) infections. 'Methicillin-resistant' means the bacteria are unaffected by Methicillin, an antibiotic that killed them in the past.

Scientists at the Medical Research Council Human Genetics Unit in Edinburgh, along with others at the Universities of St Andrews, Dundee and London, have developed a gene map which makes it easier to understand how MRSA manages to escape being killed by antimicrobial agents.

The gene map has allowed them to work out the relationships between 95 per cent of MRSA genes, and possible roles for 22 genes that help the bacterium cause disease in humans.

One particular gene, called ftsH, was singled out as a possible Achilles’ heel in MRSA and has the potential to be a focus for new drug development, the researchers said.

As part of the study, the researchers also investigated how an antimicrobial agent derived from the skin of bullfrogs kills MRSA.

Computer analysis, coupled with laboratory tests, showed that the agent - called Ranalexin - appears to work by weakening both the bacterial cell wall and membrane.

Dr Ian Overton at the MRC Human Genetics Unit said: “Multidrug resistant Staphylococcal infections such as MRSA are a worldwide problem and strains resistant to existing treatments continue to emerge. The development of new drugs is therefore important.

Our network biology approach has given insights into how Ranalexin works to kill MRSA and helped us to understand more about how infections may develop. This knowledge contributes towards new strategies for treating MRSA.”

The findings are published in BMC Systems Biology.

This article was published on Thu 12 May 2011