MOLECULAR EVOLUTION OF THE TET(M) GENE IN GARDNERELLA-VAGINALIS

Five clinical isolates of Gardnerella vaginalis known to carry the tet racycline resistance determinant Tet M were examined by hybridization and nucleotide sequencing. Four of the strains carried tet(M) genes wi th identical sequences. The two versions of the tet(M) gene found in G . vaginalis did not show complete identity with other published tet(M) sequences, but showed mosaic structures with regions of homology to t et(M) gene sequences from Tn916, Tn 1545 and the American type plasmid found in Neisseria gonorrhoeae. Hybridization studies showed that all isolates carried the tet(M) gene on a single HindII restriction fragm ent of variable length. No evidence was found for the presence of sequ ences homologous to the transposition functions of Tn916.