Antibacterial activity of silver-killed bacteria: the "zombies" effect

Sci Rep. 2015 Apr 23:5:9555. doi: 10.1038/srep09555.


We report a previously unrecognized mechanism for the prolonged action of biocidal agents, which we denote as the zombies effect: biocidally-killed bacteria are capable of killing living bacteria. The concept is demonstrated by first killing Pseudomonas aeruginosa PAO1 with silver nitrate and then challenging, with the dead bacteria, a viable culture of the same bacterium: Efficient antibacterial activity of the killed bacteria is observed. A mechanism is suggested in terms of the action of the dead bacteria as a reservoir of silver, which, due to Le-Chatelier's principle, is re-targeted to the living bacteria. Langmuirian behavior, as well as deviations from it, support the proposed mechanism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / chemistry
  • Anti-Bacterial Agents / pharmacology*
  • Mass Spectrometry
  • Microscopy, Electron, Transmission
  • Pseudomonas aeruginosa / drug effects*
  • Silver Nitrate / chemistry
  • Silver Nitrate / pharmacology*


  • Anti-Bacterial Agents
  • Silver Nitrate