Superbug silver bullet discovered
12 Jul 2010 by Evoluted New Media
A promising lead for new antibiotics that disrupts cell wall formation may be an effective weapon against dangerous bacteria like MRSA according to new research.
A promising lead for new antibiotics that disrupts cell wall formation may be an effective weapon against dangerous bacteria like MRSA according to new research.
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Scientists discover a new antibiotic that could be used to fight MRSA |
Plectasin – found in the Pezizalean fungus Pseudoplectania nigrella – is a small protein molecule that can destroy highly resistant bacteria and disrupts the formation of cell walls in bacteria so that the pathogen can no longer divide.
Plectasin behave like a thief, stealing stones from a mason, by binding to a cell-wall building block said Professor Hans-Georg Sahl from the University of Bonn.
“The building block (consisting of two sugars and five amino acids) is made inside the cells, translocated to the outside and then, by specific enzymes such as PBP2, incorporated into the cell wall polymer,” Sahl told Laboratory News, “Plectasin forms a complex with the building block named Lipid II when it appears on the outside and as a consequence the building block cannot be incorporated into the wall material.”
Plectasin is similar in its mode of action to vancomycin – a drug widely used to treat infections caused by Gram-positive bacteria and the drug of choice for treating MRSA. There are more and more bacteria becoming resistant to vancomycin, and according to Dr Tanja Schneider – also from the University of Bonn – these strains are still susceptible to plectasin.
There is no permanent solution to the resistance problem even with a new antibiotic: “It’s just a question of time until the pathogens mutate and become insensitive,” Schneider said, “It’s a never ending arms race.”
Plectasins belons to a call of small cysteine-rich cationic proteins called defensins. These defence molecule are widespread among fungi, lower animals and plants. Humans produce defensins on the skin to nip infections in the bud.
“Defensins not only kill pathogens but also alert the immune system so the pharmaceutical industry is setting its hopes on them,” said Dr Hans-Henrick Kristensen from Novozymes AS who have been working on the project with the Universities of Boon, Utrecht and Aalborg.
