Smart drugs to fight superbugs

American scientists have created a new class of smart drugs that could offer an alternative to overused antibiotics and help to solve the problem of multi-drug resistant bacteria, or superbugs.

Dr Reza Ghadiri and scientists at the Scripps Research Institute in La Jolla, California, have designed a synthetic peptide, a molecule produced by plants and animals to fight bacterial infection, with powerful antibiotic properties.

Known as cyclic peptide nanotubes, they stack up like doughnuts inside the cell membranes of bacteria and poke holes through them to kill the cells.

They offer a new approach to fighting killer bacteria that have developed a resistance to antibiotics because they have been over-prescribed.

"The bacteria haven't seen these before," Dr Ghadiri said.

In a report in the science journal Nature, the scientists described how the tubes killed infections caused by the superbug Staphylococcus aureus in mice.

"The low molecular weight peptides offer an attractive complement to the current arsenal of naturally derived antibiotics, and hold considerable potential in combating a variety of existing and emerging infectious diseases," Dr Ghadiri said.

Superbugs have flourished because doctors have overused antibiotics and scientists have failed to realise just how dynamic bacteria are.

Antibiotics have been used to treat minor ailments and often they are misused and the full course of treatment is not taken which increases the buildup of resistance.

Because the microbes multiply so quickly, some bacteria can survive an assault from even the most powerful drugs.

The World Health Organisation has warned that all big infectious diseases are developing resistance to drugs.

In Nature, Tomas Ganz, a medical professor at the University of California, Los Angeles, described the research as "an exciting advance" in the search for new antibiotics.

"A ring-shaped peptide that might puncture microbial membranes could be the way forward."

- REUTERS