A NOVEL TETRACYCLINE-RESISTANT DETERMINANT, TET(U), IS ENCODED ON THEPLASMID PKQ10 IN ENTEROCOCCUS-FAECIUM

Nine tetracycline (Tc)-resistant clinical isolates of Enterococcus fae cium were screened for plasmid content using agarose gel electrophores is. pKQ10, a 1.9-kb plasmid carrying a novel Tc resistance determinant , was isolated from one of the isolates. The nucleotide sequence of th is plasmid revealed an open reading frame corresponding to an 11.8-kDa protein and containing 105 amino acid residues. There was some limite d similarity between this protein and tet(M), ret(O), ter(Q), tet(S), terB(P), and otr(A), which overlapped, but did not include, the consen sus GTP-binding sequences. The low-level, Tc-resistant determinant of pKQ10, named ret(U), does not appear to correspond to any other known Tc resistance determinant. (C) 1996 Academic Press, Inc.