TABLE 2.

Different intimin alleles, their origins, and tissue tropism

Intimin typeCategory(ies) of E. coli,a serotypes, or species carrying the allelesHost and/or tissue specificityd
α (alpha)bEPEC 1Human proximal and distal small intestines as well as FAE
β (beta)bEPEC 2, EHEC 2, and Citrobacter rodentium, RDEC-1eAnimal and human (Peyer's patch lymphoid follicles in rabbits)
γ (gamma)bEHEC O157:H7, EPEC O55:H7, and O55:HHuman ileal FAE
δ (delta)bEPEC O86:H34Human
ε (epsilon)EHEC O8, O11, O45, O103, O121, and O165Bovine and human (O103 strains adhere to large intestine FAE)
ζ (zeta)cO84:NMBovine
η (eta)cO125: H, O84:H2Human
θ (theta)cO111:H8Human
ι (iota)cO145:H4, O98:H2Human
κ (kappa)O118:H5Human
UntypeableEPEC O127:H40Human
  • a Categories are based on the clonal relationships described by Whittam et al. (143).

  • b By restriction analysis, these intimins have been subgrouped as α1, α2, β1, β2, γ1, and γ2 (β2 is also known as δ).

  • c These are rare intimin alleles not frequently found in human isolates.

  • d FAE, follicle-associated epithelium of Peyer's patches.

  • e RDEC-1, rabbit diarrheagenic E. coli strain.