Research could turn the tables on superbugs

Dec 27 2007

Scientists in Australia and America believe they have found a way to deal with the increasing antibiotic resistance of deadly superbugs such as MRSA.

A team of researchers which includes Professor Ron Skurray and Dr. Neville Firth from the School of Biological Sciences at the University of Sydney and Dr. Maria Schumacher from the University of Texas, have been working on new ways to combat resistance.

They have already identified a potential method of stopping bacteria passing on resistance genes to the next generation when they divide.

Hospitals worldwide are facing serious problems in dealing with bacteria which are resistant to multiple types of antibiotics and particularly powerful bugs such as methicillin-resistant Staphylococcus aureus (MRSA) are entrenched in many hospitals.

The problem causes significant concern because such superbugs mean longer hospital stays and are a serious and sometimes fatal threat to patients' health.

The researchers say bacterial strains become resistant by acquiring a pre-existing resistance gene from other bacteria and this happens because resistance genes are often carried on mobile DNA molecules called plasmids, which are mini-chromosomes that can be transmitted between bacteria.

Bacteria that have these resistance genes are more likely to survive when exposed to the antibiotic, and as a result become more common.

The researchers have created a detailed picture of the golden staph bacteria's division process, and have identified a biological step they hope can be targeted to stop the plasmids being passed on to the next generation.

Lead researcher Dr. Neville Firth says it is this specific system which moves the plasmid DNA into the daughter cells when the cells divide into two - ensuring both daughter cells get a copy, rather than two in one cell and none in the other.

Dr. Firth says they hope they will eventually be able to disrupt that process and so force the cells to lose their resistance.

He says cells which lose their plasmids as a rule develop faster and become more prevalent and at present the resistance is all one way; as antibiotics are used the bacteria gets resistance and spreads and the situation gets worse.

Dr Firth suggests a biological agent designed to knock out the target, if one was found, could be included in a disinfectant to be used in hospitals and he says that would "throw a spanner in the works of the whole evolutionary process."

However such a spanner appears to be at least 10 years away but at least there does now seem to be a more detailed picture of a possible target which is an important step in being able to develop an agent, says Firth.

The researchers are looking for other possible targets within the division process.

The research, conducted in conjunction with University of Texas scientists, is published in the journal Nature.