Bacteriocin and antibiotic resistance plasmids in Bacillus cereus and Bacillus subtilis

Abstract

A number of plasmids have been isolated as covalently closed circular DNAs from strains of B. cereus and B. subtilis. From 12 out of 15 strains of B. cereus, plasmids could be isolated. Most of the B. cereus strains contained two or more plasmids. Their molecular weights ranged from 1.6x106 to 105x106. Bacteriocin production could be attributed to a 45x106-dalton plasmid (pBC7) from B. cereus DSM 336, and tetracycline resistance to a 2.8x106 plasmid (pBC16) from B. cereus GP7. Two streptomycin-resistant strains of B. subtilis harbored plasmids of 5.2x106 and 9x106, respectively, which were, however, not correlated with the antibiotic resistance. The plasmid carrying resistance to tetracycline, pBC16, which was originally isolated from B. cereus, could be subsequently transformed in B. subtilis, where it is stably maintained.