[The role of heavy metals and their derivatives in the selection of antibiotics resistant gram-negative rods (author's transl)]

Abstract

The authors have studied 116 Gram-negative strains, 27 of which were sensitive to antibiotics and 89 showed multiple resistance. The MIC of mercury chloride, mercuric nitrate and of an aqueous solution of mercuresceine were much higher in the case of the sensitive strains. The transfer of resistance to mercury, which has been achieved in 56% of cases, was always accompanied by transfer of resistance to the antibiotics. The MIC of phenylmercury borate, mercurothiolic acid and other heavy metals (such as: cobaltous nitrate, silver nitrate, cadmium nitrate, nickel nitrate, zinc nitrate, copper sulphate and sodium arsenate) are approximatively the same for all strains. The normal concentrations of mercury in nature are lower than the rate of microbial selection. But in areas of accumulation, particularly in biological chains or in hospitals, the mercury compounds could play a part in the selection of antibiotic resistant Gram-negative bacteria.