A new antibiotic discovered that quells resistance

New antibiotic may work where others have failed

Published: Friday 30 June 2006

antibiotics may get a fresh lease of life following the discovery of a potent compound by a team of scientists at Merck Research Laboratories in Rahway, New Jersey, in the us.

Called platensimycin, the compound was isolated from a fungus-like bacterium found in a soil sample from South Africa. The team was led by Sheo Singh, the firm's director for natural products chemistry. The study was published in the May 18 issue of Nature (Vol 441, No 7091). If it passes the required clinical trials, platensimycin may herald the first major new class of antibiotics in decades.

Use of antibiotics as a line of treatment is falling out of grace due to increasing resistance acquired by microbes against the drugs. Some germs, 'superbugs', have become resistant to even the most potent antibiotics, and scientists fear that this may lead to certain infections becoming incurable.

Platensimycin (derived from Streptomyces platensis) may be able to address such concerns. In trial with mice, it was found to wipe out bacteria such as methicillin-resistant Staphylococcus aureus and the enterococcus species, which have become resistant to almost all antibiotics developed so far. The scientists claim the drug apparently does not have any toxic side effects.

What is significant about platensimycin is that its mechanism of fighting microbes is radically different from the way other antibiotics work. Conventionally, all antibiotics either paralyse a microbe's ability to build a protective cell wall or prevent the bugs from synthesising proteins or dna.

The similar mode of action of antibiotics means that microbes that become resistant to one antibiotic can often withstand many others as well. But the new Merck compound targets bacterial fatty acid synthesis. It binds to a crucial enzyme in the fatty acid pathway.

As many enzymes involved in synthesis of fatty acids in pathogenic microbes are highly conserved, the bugs may not be able to withstand the onslaught of the new drug by producing variant forms of the targeted enzymes.

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