Silver-tainted "zombie" bacteria kill other bacteria

Silver has long been known to possess potent anti-bacterial properties. Silver damages bacterial membranes, penetrate the cells, bind DNA and inhibit essential functions for bacterial survival. This proves deadly to bacteria. New research suggests that silver-treated bacteria retain silver particles in their bodies after death, and the dead bacteria remain as a toxic vehicle for other surrounding bacteria. According to Emily Conover at AAAS, the researchers:

"First killed a sample of the bacterium Pseudomonas aeruginosausing a solution of silver nitrate. Then, they carefully separated the dead bacteria from the silver solution. When they exposed living bacteria to the dead, they witnessed a microscopic massacre-Up to 99.99% of the living bacteria met their doom."

Microscope images of P. aeruginosa before (a and d) and after (b, c and e) silver treatment; the black (b) and white (e) granules are silver deposits that trigger the "zombies" biocidal activity. Copyright 2015, Wakshlak et al. doi:10.1038/srep09555.

What is interesting about this finding is that silver solutions have long been used for its anti-septic and anti-germicidal properties. This new research suggests that bacteria exposed to silver take it up, die, and act like bacterial "zombies" when exposed to other healthy bacteria. So, rather than creating devices or engineered materials to release silver over a time-course for sustained silver release and thus, anti-bacterial efficacy of a silver treatment, recirculating silver-"infected" bacteria could also generate an extended temporal ability to promote bacterial death. Mostly, I think it is interesting that a simple experiment changed the perspective and potential use of a long utilized chemical for medically-related purposes. There are still basic experiments and simple ideas out there can that can make an impact if you know where to look and have an idea what you are looking for.

Racheli Ben-Knaz Wakshlak, 

Rami Pedahzur

& David Avnir

 (2015) Antibacterial activity of silver-killed bacteria: the "zombies" effect. 

Scientific Reports

 

5,

 

Article number:

 

9555

 

doi:10.1038/srep09555.

http://www.nature.com/srep/2015/150330/srep09555/full/srep09555.html

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