New antibiotic active against resistant bugs

NEW YORK (Reuters Health) - Researchers have discovered a natural antibiotic with a unique mechanism of action that allows it to knock out several bacteria that are often resistant to other agents, such as methicillin-resistant Staphylococcus aureus -- commonly known as MRSA.

The antibiotic, named platensimycin, is an antimicrobial compound produced by a bacterium called Streptomyces platensis. The antibiotic was discovered by screening 250,000 natural products, and came from "a strain of Streptomyces platensis recovered from a soil sample collected in South Africa."

In lab dish experiments and animal studies, Dr. Jun Wang and colleagues, from Merck Research Laboratories in Rahway, New Jersey, showed that platensimycin has potent, broad-spectrum activity against multiple microbes.

The drug works by blocking microbes' ability to synthesize lipids, which is essential for the bugs to survive.

In mice, treatment with platensimycin eradicated Staphylococcus aureus infection. In addition, further testing showed activity against a variety of drug-resistant organisms, including MRSA.

Also, platensimycin has "no observed toxicity," the researchers note.

They conclude that the discovery "provides a great opportunity for the development of critically need antibiotics."

SOURCE: Nature, May 18, 2006.