Genetic basis of tetracycline and minocychine resistance in potentially probiotic Lactobacillus plantarum strain CCUG 43738

The potentially probiotic strain Lactobacillus plantarum CCUG 43738, which displayed atypical phenotypic resistance to tetracycline (MIC, 512 mu g/ml) and minocycline (MIC, 256 mu g/ml), was found to contain a tet(S) gene located on a plasmid of approximately 14 kb. Plasmid curing with novobiocin eliminated this plasmid and restored the tetracycline-susceptible phenotype of the host strain.