TETRACYCLINE RESISTANCE DETERMINANTS AMONG STREPTOCOCCI OF SEROLOGICAL GROUP-G AND GROUP-L

In the present study 56 streptococci of serological group G and L isol ated from various animal species and from humans were investigated for tetracycline and minocycline resistance and for the presence of genes conferring this combined resistance. Among the 45 group G streptococc i, 2 isolates from dogs, 3 from cattle and 2 from humans, respectively , as well as all 11 group L streptococci isolated from cable, pigs or poultry were resistant to tetracycline and simultaneously to minocycli ne. The restriction endonuclease digested and blotted DNA-preparation of the tetracycline-and minocycline resistant group G streptococci fro m dogs and humans hybridized with the tet (M) gene probe, those from b ovines with the tet (O) gene probe. Six group L streptococci carried t he gene tet (M), whereas 5 isolates harboured the gene tet (O). The te t (M)-and tet (O) gene probes recognized complementary sequences on Ec oRI-fragments of various sizes.