Mechanism of mercuric chloride resistance in microorganisms, 1

Three strains of Escherichia coli possessing the multiple drug resistance were found to be resistant also to HgCl2, though they were sensitive to other heavy metal ions such as nickel, cobalt, cadmium and zinc ions. Like the resistance to drugs such as chloramphenicol and tetracycline, the HgCl2 resistance could be transferred from a resistant strain of E. coli to sensitive strains of E. coli and Aerobacter aerogenes. The resistant strains could grow in the presence of 0.02 mM HgCl2, whereas a sensitive strain failed to grow in the presence of 0.01 mM HgCl2. During cultivation in the presence of HgCl2, the cells of resistant strain vaporized a form of radioactive mercury when incubated with 203HgCl2, glucose and NaCl in phosphate buffer while the cells of sensitive strain showed no such activity. This phenomenon seemed to explain the HgCl2 resistance of the resistant strains.