Ciamak Ghazaei - Department of microbiology,Mohaghegh Ardabili University,Ardabil,Iran

Several metals such as copper, mercury, zinc, silver, arsenic and antimony have been applied since the pages of history in the treatment of bacterial diseases. While most metals have key roles in the metabolism in organisms, certain metals are toxic and while others are deleterious beyond a critical level. Research has shown that bacteria have evolved several pathways for homeostasis of these metals within the cell to ensure their survival even if the levels of the metals are high. These sophisticated mechanisms include chelation, EPS, metabolic bypass channels, enzymes that volatilize the metals, impermeability to metals and several mechanisms of efflux of metals from the cell.The levels of metals within the cell can be sensed and regulated by sensitive molecules called metal sensors that either upregulate the systems for efflux of metal or downregulate the import of metals within the cell. Studies have also shown a link between metal resistance as well as antibiotic resistance in certain cases, in the form of mobile genetic elements. This review also covers the specific pathways involved in the resistance of bacteria to metals: copper, arsenic, antimony, mercury, zinc and silver.

Bacteria, Metal resistance,Enzymes, Antibiotic,Copper