TABLE 6

Main characteristics of known resistance plasmids in Enterobacteriaceae

IncaReplicon(s)Rep domainbCopy no.cMOBdHost rangeConjugation or pilus descriptione
A/C (P-3)A/CLMOBH12BroadThick and flexible
FFIIFIILMOBF12EnterobacteriaceaeThick and flexible
FIARep_3
FIBRep_3
G (P-6)GLMOBP14Broad, γMobilizable
HI1HI1AeLMOBH11EnterobacteriaceaeThick and flexibleg
HI1B
FIA-like repliconRep_3
HI2HI1AfLMOBH11EnterobacteriaceaeThick and flexibleg
HI2f
I complexI1/Iγ/B/O/K/ZFIILMOBP12EnterobacteriaceaeRigid plus thin and flexibleh
I2I2FIILMOBP6EnterobacteriaceaeRigid plus thin and flexibleh
J (ICE)JMOBH12Thick and flexible
L/ML/MFIILMOBP13Broad, α, β, γRigid
NNRep_3LMOBF11BroadRigid
P (P-1)PRep_3LMOBP111Broad, α, β, γRigid
Q-1Q-1RepCHMOBQ1Gram-negative and -positive bacteriaMobilizable
Q-3Q-3RepCH?BroadMobilizable
RRRep_3L?
TTfLMOBH12?Thick and flexibleg
UULMOBP4Broad, α, β, γRigid
WWRep_3LMOBF11Broad, α, β, γRigid
XXRep_3LMOBP3EnterobacteriaceaeThin and flexible
YYfLEnterobacteriaceaePlasmid-like prophage
ColE1ColE1RNA IIHMOBP5/HENiMobilizable
  • a P-numbers show designations used for Pseudomonas.

  • b All plasmid types use a θ replication mechanism, except for Q plasmids, which use a strand displacement mechanism. Rep domains (see text on plasmids in Gram-positive bacteria for more details) from the conserved domains database (CDD) (141) were identified using BLASTp searches. —, no Rep domain identified in BLASTp searches. ColE1-like plasmids encode an RNA primer rather than a replication initiation protein.

  • c H, high; L, low.

  • d MOB type usually associated with the replicon(s) in known resistance plasmids. For details of MOB classification, see reference 174.

  • e From reference 512.

  • f RepHI1A, HI2, T, and Y replicons seem to belong to the same protein family.

  • g Conjugation is temperature sensitive (209), and host range appears to be broader at lower temperatures (513).

  • h The PilV tip adhesin of the thin pilus is varied by the shufflon recombination system.

  • i HEN stands for amino acids H97, E104, and N106, whereas most relaxase active sites have three histidines (311).