Concentrations of Copper Thought To Be Toxic to Escherichia coli Can Induce the Viable but Nonculturable Condition

We have determined that concentrations of copper considered to be toxic can induce a fraction of a population of Escherichia coli to enter the viable but nonculturable (VBNC) condition. Copper-induced VBNC cells could be resuscitated for up to 2 weeks after entering the VBNC state.