Researchers rely on nanotechnology to battle superbugs

October 13th, 2008 - 4:30 pm ICT by IANS  

Toronto, Oct 13 (IANS) Researchers are using the nanomechanical approach to probe the workings of Vancomycin, one of the few antibiotics that can combat highly resistant infections such as MRSA or methicillin-resistant Staphylococcus aureus. Researchers, led by Rachel McKendry and Gabriel Aeppli, of London Centre for Nanotechnology (LCN), University College of London (UCL), developed ultra-sensitive probes capable of providing new insight into how antibiotics work, paving the way for the development of more effective new drugs.

During the study McKendry, Joseph Ndieyira, Moyu Watari and coworkers used cantilever arrays - tiny levers no wider than a human hair - to examine the process which ordinarily takes place in the body when vancomycin binds itself to the surface of the bacteria.

They coated the cantilever array with mucopeptides from bacterial cell walls and found that as the antibiotic attaches itself, it generates a surface stress on the bacteria which can be detected by a tiny bending of the levers. The team suggests that this stress contributes to the disruption of the cell walls and the breakdown of the bacteria.

The interdisciplinary team went on to compare how vancomycin interacts with both non-resistant and resistant strains of bacteria. The ’superbugs’ are resistant to antibiotics because of a simple mutation which deletes a single hydrogen bond from the structure of their cell walls, according to a release of UCL.

This small change makes it approximately 1,000 times harder for the antibiotic to attach itself to the bug, leaving it much less able to disrupt the cells’ structure, and, therefore, therapeutically ineffective.

“There has been an alarming growth in antibiotic-resistant hospital ’superbugs’ such as MRSA and vancomycin-resistant Enterococci (VRE),” said McKendry. “This is a major global health problem and is driving the development of new technologies to investigate antibiotics and how they work.

“The cell wall of these bugs is weakened by the antibiotic, ultimately killing the bacteria,” she continued. “Our research on cantilever sensors suggests that the cell wall is disrupted by a combination of local antibiotic-mucopeptide binding and the spatial mechanical connectivity of these events. Investigating both these binding and mechanical influences on the cells’ structure could lead to the development of more powerful and effective antibiotics in future.”

“This work at the LCN demonstrates the effectiveness of silicon-based cantilevers for drug screening applications,” added Gabriel Aeppli, director LCN.

These findings were published on Sunday in Nature Nanotechnology.

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