Beating Bacteria with Bacteria

New Antibiotic Tackles Multi-Resistant Germs

There is new hope in the battle against bacterial pathogens resistant to “last line of defence” drugs. Scientists at the German Research Centre for Biotechnology (GBF) in Braunschweig have discovered a novel – and natural – substance that inhibits the growth of such bacteria. This new substance, which goes by the name MMA, or 7-O-malonyl-macrolactin A, has proven effective against several multi-resistant germs. Its discovery is published in the latest issue of Antimicrobial Agents and Chemotherapy.
“Multi-drug resistance in infectious agents, particularly in hospitals, is one of the most important challenges facing medicine today”, explains Professor Timmis, Head of the Division of Microbiology in the GBF. “The widespread non-clinical use of antibiotics as growth promoters in animal feeds and, more recently, in aquaculture, has resulted in the rapid evolution and spread of resistance to a wide range of antibiotics in pathogenic microbes, and compromised the clinical management of infections. Moreover, the exceptional success of early antibiotics in the treatment of infections led to complacency and a focusing on other diseases and treatments. As a result, the pipeline of new antibiotics is practically empty, so that the prospects of new antibiotics effective against current multi-resistant bugs are bleak.”
The new antibiotic, MMA, was discovered through a GBF research programme to explore new microbial diversity for new drugs, and involved a collaboration with Indonesian colleagues. It is produced by a new strain of the soil bacterium Bacillus subtilis, which may produce it as an ecological weapon to compete with other bacteria in the soil. According to Professor Timmis, “more than 90% of thus far unexplored biodiversity is microbial diversity, so the microbial world represents a treasure chest for future discoveries of new drugs and other useful bioproducts”.

MMA versus MRSA

GBF scientists see a promising future for MMA, which not only inhibits MRSA, the notorious strain of methicillin-resistant Staphylococcus aureus, but also vancomycin-resistant enterococci (VRE), both of which cause potentially lethal infections in hospitalized patients. MMA inhibits cell division by the bacteria, so they are unable to divide and spread. "Antibiotics have been our strongest weapon against bacterial pathogens," explains Dr. Gabriella Molinari, Head of the Drug Discovery Unit of the GBF. " The acquisition of new weapons to either kill or inhibit bacterial growth is one of the greatest imperatives in medicine, so MMA and other lead molecules spinning-off our natural products drug discovery program are promising tools in the fight against infections ”. However, it will take a few more years before it is known whether MMA can find its way into the clinic. "The substance first needs to be studied more closely and thoroughly tested," notes Dr. Molinari, “and ultimately clinical trials will be needed to show whether MMA is really suitable for human use."

Source Material for the Media

Further information is provided in the original article: M. Romero-Tabarez, R. Jansen, M. Sylla, H. Lünsdorf, S. Häußler, D. Santosa, K. Timmis, G. Molinari. 7-O-Malonyl Macrolactin A, a New Macrolactin Antibiotic from Bacillus subtilis Active against Methicillin-Resistant Staphylococcus aureus, Vancomycin-Resistant Enterococci, and a Small-Colony Variant of Burkholderia cepacia. Antimicrob. Agents Chemother. 2006 50: 1701-1709. (http://aac.asm.org/)

Photo legend

GBF scientist Dr. Gabriella Molinari
Photograph: GBF/Bierstedt

Searching for new antibiotics: A test for substances that inhibit the growth of bacteria.
Photograph: GBF/Bierstedt

A dangerous resistant pathogen: Staphylococcus aureus.
Photograph: GBF/Bierstedt

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