Marine bugs give new antibiotic hope
20 May 2011 by Evoluted New Media
Hybrid antibiotics may be key to wiping out drug-resistant strains of the MRSA superbug say researchers from the Universities of Bristol and Birmingham.
Hybrid antibiotics may be key to wiping out drug-resistant strains of the MRSA superbug say researchers from the Universities of Bristol and Birmingham.
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Hybrid antibiotics may be key to fighting MRSA Credit pre4med/flickr |
Chemists from Bristol and microbial geneticists from Birmingham discovered how marine bacteria join together two antibiotics they make independently of each other to produce a potent chemical that can kill drug-resistant strains of MRSA.
They hope these hybrid antibiotics could help solve the problem of bacterial infections which are resistant to virtually all antibiotics.
Researchers determined the sequence of the complete DNA content of the marine bacterium –Pseudoalteromonas SANK73390 – which produced the new antibiotic, thiomarinol. Thiomarinol is owned by Japanese pharmaceutical company Daiichi-Sankyo, who were also involved in the work.
They then identified genes responsible for making the antibiotic on the basis of their similarity to genes that make the related but less potent antibiotic mupirocin. The genes are located on a plasmid – a relatively small separate DNA molecule just big enough to carry genes for autonomous replication and to produce the antibiotic.
The plasmid carries genes to make the mupirocin-like antibiotic, plus a second antibiotic – holomycin – and a gene responsible for joining the antibiotics together to form a more potent molecule. The resulting chemical is able to inhibit the growth of MRSA strains that have become resistant to mupirocin, which is currently used to treat the superbug.
“This shows how mupoirocin can be modified to make it more potent and suggests that related molecules could be used against the increasingly problematic Enterobacteriacae like Escherichia coli and Klebsiella pneumonia,” said lead researcher Professor Chris Thomas.
By using mutant strains unable to make the mupirocin or holomycin part, the team fed alternative compounds to bacteria in a process called mutasynthesis to create a family of novel molecules. Some of these showed biological activity in tests.
“This provides hope that the system will allow the production of new antibiotics that may help to combat the growing problem of antibiotic resistance in pathogenic bacteria,” said Thomas.
