[Researches on metal-resistance and conjugation-transfer in "Escherichia coli" strains (author's transl)].

The resistance for HgCl2, NaAsO2, Co(NO3)2, NiSO4, ZnSO4, Agtno3, and CdSO4 in 40 strains of Escherichia coli, was investigated. In 16 of 23 Hg-resistant strains, resistance transfer was obtained by means of conjugation with Salmonella typhi. Hg-resistance was present only in antibiotic-resistant strains, but no correlation was possible with any antibiotic-resistance determinants: because Hg-resistance transfer may occur independently, and it is possible to obtain clones spontaneously segregant for the mentioned trait. As for the possible mechanisms of bacterial metal-resistance, several hypothesis were prospected, the most credible one that of a detoxification of the metallic salt.