TABLE 1

Examples of IS and composite transposons associated with resistance genes in Gram-negative bacteria

ISaTnbDeterminantResistance(s)c
IS1Tn9catA1Chloramphenicol
IS10Tn10tet(B)Tetracycline
IS26dTn4352aphA1Kanamycin
Tn6020aphA1Kanamycin
tet(C)Tetracycline
tet(D)Tetracycline
catA2Chloramphenicol
Tn2003blaSHVβ-Lactams
cfrPhenicols/lincosamides/oxazolidinones/pleuromutilins/streptogramin A
IS256ecfrPhenicols/lincosamides/oxazolidinones/pleuromutilins/streptogramin A
IS50Tn5aph(3′)-IIa-ble-aph(6)-IcKanamycin, bleomycin, streptomycin
IS903Tn903aphA1Kanamycin
IS1999Tn1999blaOXA-48-likeCarbapenems
ISApl1Tn6330mcr-1Colistin
ISEc69mcr-2Colistin
ISAs2blaFOX-5BLBLI
ISAba14TnaphA6aphA6Kanamycin
ISAba1Tn2006blaOXA-23Carbapenems
blaOXA-237Carbapenems
ISAba125Tn125blaNDMCarbapenems
  • a See ISfinder (https://www-is.biotoul.fr/) for details of IS.

  • b See the Tn registry (http://transposon.lstmed.ac.uk/) for further details, except for TnaphA6 (334).

  • c SHV enzymes can be broad-spectrum or extended-spectrum β-lactamases; BLBLI, β-lactam–β-lactamase inhibitor combinations.

  • d Regions flanked by two copies of IS26 and originally defined as composite transposons are listed, but recent findings suggest mobilization by a single copy of IS26 (see the text).

  • e IS256 is normally associated with Gram-positive bacteria (see Table 2); cfr is found in the same IS256-flanked transposon in Staphylococcus lentus (INSDC accession number KF029594).