Elimination of mercury, cadmium and antibiotic resistance from Acinetobacter lwoffi and Micrococcus sp. at high...

Resistance determinants for HgCl2 and CdCl2 were eliminated along with a number of antibiotic resistance factors from Acinetobacter lwoffi and Micrococcus sp. at 44 degrees C. These organisms were orginally resistant to HgCl2, merbromin, CdCl2, Pb(NO3)2, benzylpenicillin, erythromycin, carbenicillin, tetracycline and sulfadiazine. Four different types of mutants from A. lwoffi (type I to IV) and one type of mutant from Micrococcus sp. (type V) were obtained, depending on the loss of particular resistance factors for HgCl2, merbromin, CdCl2 and antibiotics. In general, frequency of elimination of all the missing markers was very low (in the range of 10(-3) per bacterium). However, the missing determinants did not revert spontaneously.