'Nanotech search' for antibiotics

UK researchers are using microscopic "nanoprobes" to find new drugs to tackle antibiotic resistance.

The tiny ultra-sensitive probes can measure how well a drug binds to bacteria and its ability to weaken and destroy the bug.

The researchers tested the silicon-based technology on vancomycin, one of the few remaining antibiotics against infections such as MRSA

The initial results are published in Nature Nanotechnology.

It is the first time this type of nanotechnology has been used in screening for new drugs.

The probes are no wider than a human hair - which may seem big by nanotechnology standards - but they are able to detect minute changes at the molecular level.

Antibiotics such as vancomycin bind to the bacterial cell wall, disrupting it and causing the bacteria to break down.

When bacteria become resistant, small changes occur in the structure of their cell wall making it far harder for the antibiotic to latch on and weaken the structure of the cell.

'Surface stress'

The researchers from the London Centre for Nanotechnology coated a series of the nanoprobes with the proteins that make up bacterial cell walls.

Like a tiny row of diving boards, the probes bend in response to the "surface stress" that occurs when the antibiotic binds to the cell.

The system was able to detect that it is 1,000 times harder for vancomycin to attach to resistant bacteria than to non-resistant bacteria.

They are now screening other potential antibiotics with the goal of finding a drug that is able to bind strongly to resistant bacteria and cause substantial structural weaknesses to the cell wall.

Study leader Dr Rachel McKendry said: "There has been an alarming growth in antibiotic-resistant hospital 'superbugs' such as MRSA and vancomycin resistant Enterococci (VRE).

"This a major global health problem and is driving the development of new technologies to investigate antibiotics and how they work."

She added that different drugs caused different structural weaknesses in the cell wall - some of which were more effective than others - and the nanotechnology they were using could help to pinpoint those that were likely to cause the most destruction.

Professor Jeff Errington, director of the Institute for Cell and Molecular Biosciences at the University of Newcastle said the technology was very interesting and obviously highly sensitive.

But he said it did not solve the problem of finding new antibiotics to test in the first place.

"The bottleneck is in finding new molecules that kill bacteria by novel pathways," he said.