TABLE 6.
Frequency of virulence factor genes in E. coli isolates belonging to the B2 and D phylogroupsa
| VFG | Gene product (category) | Activity/effect | Pathotype(s) | No. of isolates (% prevalence) |
|
|---|---|---|---|---|---|
| Group B2 (n = 21) | Group D (n = 23) | ||||
| sfa/foc | Adhesin | Adhesion and colonization of uroepithelium and endothelium | UPEC, MNEC | 3 (14) | 0 |
| afa | Adhesin | Adhesion and colonization of uroepithelium, cytopathic effects | DAEC, UPEC | 0 | 0 |
| pap | Adhesin | Induction of cytokine expression, adhesion and colonization of uroepithelium | UPEC | 2 (9.5) | 0 |
| eaeA | Intimin | Adhesion and colonization of epithelial cells, induction of TH1 immune responses | EPEC, STEC | 2 (9.5) | 2 (8.7) |
| fyuA | Siderophore | Iron acquisition | Various | 15 (71) | 7 (30) |
| aer | Siderophore | Iron acquisition | EIEC, MNEC | 2 (9.5) | 3 (13) |
| stx1 | Toxin | Inhibition of protein synthesis, apoptosis induction | STEC | 0 | 0 |
| stx2 | Toxin | Inhibition of protein synthesis, apoptosis induction | STEC | 0 | 0 |
| hlyA | Alpha-hemolysin | Cell lysis | UPEC | 2 (9.5) | 0 |
| ibeA | Membrane protein | Promotes invasion | MNEC, UPEC | 13 (62) | 5 (22) |
| traT | Membrane protein | Serum survival | MNEC | 11 (52) | 13 (56) |
a
VFG, virulence factor gene; UPEC, uropathogenic E. coli, MNEC, sepsis-and meningitis-associated E. coli; DAEC, diffusely adherent E. coli; EPEC, enteropathogenic E. coli; STEC, Shiga toxin-producing E. coli; EIEC, enteroinvasive E. coli.