Cobalt stress in Escherichia coli and Salmonella enterica: molecular bases for toxicity and resistance

Metallomics. 2011 Nov;3(11):1130-4. doi: 10.1039/c1mt00099c. Epub 2011 Sep 26.


Cobalt (Co) is present in trace amounts in the environment but it can be toxic when it accumulates in cells. The question of how Co produces its toxic effects and how living organisms protect themselves from, and resist to, such a stress remains to be clarified. Studies pertaining to these issues were recently carried out in Escherichia coli and Salmonella enterica. Iron-sulfur proteins were identified as primary targets of Co ions. Perturbation of iron homeostasis, oxidative stress and possible effects on sulfur assimilation were noticed. Cells were found to respond by up-regulating genes involved in the biosynthesis of Fe-S clusters as well as genes involved in Co efflux. These data are summarized in this review article to provide a preliminary general view of Co toxicity mechanisms in these two bacterial models.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Cobalt / pharmacology*
  • Drug Resistance, Bacterial / physiology*
  • Escherichia coli / drug effects*
  • Escherichia coli / genetics
  • Escherichia coli / metabolism*
  • Gene Expression Regulation, Bacterial / drug effects
  • Homeostasis
  • Iron / metabolism
  • Iron-Sulfur Proteins / genetics
  • Iron-Sulfur Proteins / metabolism
  • Oxidative Stress / drug effects
  • Salmonella enterica / drug effects*
  • Salmonella enterica / genetics
  • Salmonella enterica / metabolism*
  • Sulfur / metabolism


  • Bacterial Proteins
  • Iron-Sulfur Proteins
  • Cobalt
  • Sulfur
  • Iron