Table 1.
Distribution of genes coding for virulence factors and quinolone resistance among phylogenetic groups of intI-positive E. coli strains isolated from a wastewater treatment plant
| Virulence factor gene | Virulence factor | Prevalence in phylogenetic groups | ||||
|---|---|---|---|---|---|---|
| A (n = 33) | B1 (n = 21) | B2 (n = 15) | D (n = 40) | Total (n = 109) | ||
| eae | Intimin | 0 | 1 (4.8%) | 1 (6.7%) | 1 (2.5) | 3 (2.8%) |
| ST gene* | Heat-stable toxin | 2 (6.1%) | 7 (33.3%) | 0 | 3 (7.5%) | 12 (11.0%) |
| stx1, stx2 | Shiga toxin | 3 (9.1%) | 1 (4.8%) | 2 (13.3%) | 1 (4.8%) | 7 (6.4%) |
| fyuA | Yersiniabactin | 9 (27.3%) | 3 (14.3%) | 7 (46.7%) | 10 (25%) | 29 (26.6%) |
| iutA* | Aerobactin | 10 (30.3%) | 8 (38.0%) | 10 (66.7%) | 17 (52.5%) | 45 (41.3%) |
| hlyA | Haemolysin A | 1 (3.0%) | 1 (4.8%) | 1 (6.7%) | 1 (2.5%) | 4 (3.7%) |
| papA | P fimbriae | 5 (15.2%) | 3 (14.3%) | 2 (13.3%) | 8 (20.0%) | 18 (16.5%) |
| sfaS | S fimbriae | 9 (27.2%) | 4 (19.0%) | 2 (13.3%) | 3 (7.5%) | 18 (16.5%) |
| focG | F1C fimbriae | 2 (6.1%) | 2 (9.5%) | 2 (13.3%) | 4 (7.5%) | 10 (9.2%) |
| cnf1 | CNF | 1 (3.0%) | 1 (4.8%) | 1 (6.7%) | 2 (2.5%) | 5 (4.6%) |
| VF score (mean) | 0–4 (1.24) | 0–4 (1.52) | 0–5 (1.87) | 0–4 (1.28) | 0–5 (1.40) | |
| Quinolone resistance | 19 (57.6%) | 13 (61.9%) | 9 (60.0%) | 20 (50.0%) | 61 (56.0%) | |
| Fluoroquinolone resistance | 14 (42.2%) | 9 (42.9%) | 9 (60.0%) | 23 (57.5%) | 55 (50.4%) | |
* Statistically significant differences among phylogenetic groups (P < 0.05)