title: Identification of tetracycline-resistant R-plasmids in Streptococcus agalactiae (group B).
abstract: In this report, 30 tetracycline-resistant clinical isolates of group B Streptococcus were examined to assess the extent to which tetracycline resistance is plasmid mediated. Of these, 27 showed no physical or genetic evidence of plasmid-mediated resistance; however, one conjugative and two small (3.5 X 10(6)-dalton) multicopy non-self-transmissible tetracycline resistance plasmids were identified. The conjugative plasmid was transmissible to Streptococcus faecalis as well as to Streptococcus agalactiae (group B). The two nonconjugative plasmids were readily mobilized by a number of sex factors into these same two backgrounds and, in addition, readily transformed Streptococcus sanguis Challis to tetracycline resistance. Due to readily available sites for several site-specific endonuycleases, these small, multicopy plasmids should prove useful as cloning vehicles in this host system.
mesh_terms: D003470:Culture Media; D011815:R Factors; D013292:Streptococcus agalactiae / Q000187:drug effects*; D013754:Tetracyclines / Q000494:pharmacology*; D014169:Transformation, Bacterial
chemical_list: D003470:Culture Media; D013754:Tetracyclines