In the last decades, more and more bacteria have acquired resistance to currently available antibiotics. In attempt to cope with increasing number of drug-resistant microbes, scientists are perpetually on the hunt for novel naturally produced antibiotics, or producing semi-synthetic compounds based on natural compounds. Genetic engineering have also been attempted to produce new antimicrobials.

Such is the approach taken by Daniel Santi of the Hayward, California-based polyketides, a class of molecules that are particularly difficult to produce because of their structure. Polyketides contain large rings of carbon and oxygen atoms, and include the well-known antibiotic erythromycin.

By inserting DNA sequences that produce parts of the proteins into E. coli, they were able to make E. coli produce the necessary building blocks for polyketides. And by adding special sequences to the ends of their genetic fragments, the protein fragments then "stick together" to assemble into new conformations and new polyketides.

The advance is welcome in a field running dry of ways to make new antibiotics, says pharmacologist Jon Clardy of the Harvard Medical School in Boston. "The need is obvious, and there has been very little in the way of new antibiotics in the past decade," he says.

Read the Nature report here. Research results are published in Nature Biotechnology: Menzella H. G., et al. Nature Biotech., Advanced Online Publication, doi: 10.1038/nbt1128 (2005).