Synergistic cytotoxicity between pentachlorophenol and copper in a bacterial model

Both pentachlorophenol (PCP) and copper compounds have been widely used as wood preservatives, and are commonly found not only in the area near wood-preserving facilities, but also in body fluids and tissues of people who are not occupationally exposed to them. In this study, we found that exposing bacteria to a combination of PCP and copper at non- or sub-toxic concentrations resulted in enhanced cytotoxic effect in a synergistic mode as indicated by both the inhibition of growth and the lowering of the colony-forming ability. The toxicity of the combination PCP/ Cu(II) was relieved by hydrophilic chelating agents, thiol compounds and adventitious proteins, but was markedly potentiated by low levels of the lipophilic metal chelating agents.