Abstract
417 strains of Proteus mirabilis were isolated and studied for their resistance to three metals and four drugs. Distribution patterns of susceptibility clearly revealed two peaks of resistance to Hg, Cd, and As, but only one peak in the case of Pb. The frequencies of resistance to Hg, Cd, As, SM, TC, CP, and KM were 28.8, 95.7, 57.1, 50.1, 41.7, 32.1, and 29.5%, respectively. And the frequency of Hg resistance in P. mirabilis isolates was 58.3% during 1975 to 1977 and decreased to 16.8% in 1979 to 1982.
Among these isolates, 120 Hg-resistant strains were tested for their ability to transfer this resistance to mercury and drug-sensitive recipients of E. coli K12-ML1410-Nx and E. coli JE17-Rif. 107 of these, or 89%, demonstrated Hg-resistant transferable R plasmids.
Further, using radioactive 203Hg2+, we tested the ability of strains containing these plasmids to volatilize mercury. It was found that all of these strains have inducible ability to volatilize to inorganic mercury.
