Table 3.

Mechanisms of resistance for characterized tet and otrgenesa

Genes
Efflux
tet(A),tet(B), tet(C), tet(D),tet(E), tet(G), tet(H),tet(I), tet(J),  tet(Z),tet(30)b tet(31)b
tet(K),tet(L)
otr(B),tcr3c
tetP(A)
tet(V)
tet(Y)d
Ribosomal protection
tet(M), tet(O),tet(S), tet(W)
tet(Q),tet(T)
otr(A),tetP(B),e tetc
Emzymatic,tet(X)
Unknownf
tet(U),otr(C)
  • a Grouped according to McMurry and Levy (173).

  • b First numbered genes (150).

  • c These genes have not been given new designations (150).

  • d Relatedness to groups 1 to 6 is unclear, since the gene has not been studied extensively.

  • etetP(B) is not found alone, andtetP(A) and tetP(B) are counted as one gene (164, 273).

  • f tet(U) has been sequenced but does not appear to be related to either efflux or ribosomal protection proteins; otr(C) has not been sequenced (207,220).