TABLE 2.
Virulence gene characterization of the 52 O25:H4-ST131 ibeA-positive E. coli strains included in this studya
| Category | Gene(s) | Comment(s) | No. (%) of strains |
P valueb | ||
|---|---|---|---|---|---|---|
| Avian strains (n = 19) | Human ibeA-positive strains (n = 33) | Avian and human strains (n = 52) | ||||
| Adhesins | fimH | d-Mannose-specific adhesin, type 1 fimbriae | 19 (100) | 33 (100) | 52 (100) | 1.000 |
| fimAvMT78 | FimA variant MT78 of type 1 fimbriae | 0 | 0 | 0 | ||
| pap | Pilus associated with pyelonephritis (P fimbriae) | |||||
| papEF | Pilus assembly, central region of pap operon | 1 (8.3) | 12 (36.4) | 13 (25) | 0.011 | |
| papGI | Gal(α1-4) Gal-specific pilus tip adhesin molecule rare | 0 | 0 | 0 | ||
| papGII | Pyelonephritis-associated gene | 1 (8.3) | 0 | 1 (2) | 0.365 | |
| papGIII | Cystitis-associated gene | 0 | 12 (36.4) | 12 (23.1) | 0.002 | |
| sfa and focDE | Central region of sfa and foc operons | 0 | 0 | 0 | ||
| afa and draBC | Dr antigen-specific adhesin operons (AFA, Dr, F1845) | 0 | 5 (15.1) | 5 (9.6) | 0.091 | |
| bmaE | Blood group M-specific adhesin | 0 | 1 (3) | 1 (1.9) | 0.635 | |
| gafD | N-Acetyl-d-glucosamine-specific (G, F17c) fimbria adhesin | 0 | 0 | 0 | ||
| Toxins | cnf1 | Cytotoxic necrotizing factor 1 | 0 | 1 (3) | 1 (1.9) | 0.635 |
| cdtB | Cytolethal distending toxin | 1 (8.3) | 17 (51.5) | 18 (34.6) | 0.001 | |
| sat | Secreted autotransporter toxin | 0 | 7 (21.2) | 7 (13.5) | 0.032 | |
| hlyA | α-Hemolysin | 0 | 1 (3) | 1 (1.9) | 0.635 | |
| Siderophores | iucD | Ferric aerobactin receptor (iron uptake, transport) | 17 (89.5) | 24 (72.7) | 41 (78.8) | 0.142 |
| iroN | Novel catecholate siderophore receptor | 19 (100) | 17 (51.5) | 36 (69.2) | 0.000 | |
| Protectins | kpsMII | Group II capsule | 19 (100) | 33 (100) | 52 (100) | 1.000 |
| kpsMIIK2 | K2 group II capsule | 0 | 0 | 0 | ||
| kpsMIIK5 | K5 group II capsule | 5 (26.3) | 26 (78.8) | 31 (59.6) | 0.000 | |
| neuCK1 | K1 antigen | 14 (73.7) | 7 (21.2) | 21 (40.4) | 0.000 | |
| kpsMII | Group III capsule | 0 | 0 | 0 | ||
| cvaC | ColV; on plasmids with traT, iss, and antibiotic resistance genes | 17 (89.5) | 19 (57.6) | 36 (69.2) | 0.016 | |
| iss | Increased serum survival (outer membrane protein) | 19 (100) | 20 (60.6) | 39 (75) | 0.001 | |
| traT | Surface exclusion, serum survival (outer membrane protein) | 19 (100) | 28 (84.8) | 47 (90.4) | 0.091 | |
| Miscellaneous | malX (PAI) | Pathogenicity-associated island marker | 19 (100) | 33 (100) | 52 (100) | 1.000 |
| usp | Uropathogenic strain-specific protein (bacteriocin) | 19 (100) | 33 (100) | 52 (100) | 1.000 | |
| tsh | Tsh (temperature-sensitive hemagglutinin) serine protease | 15 (78.9) | 5 (15.1) | 20 (38.5) | 0.000 | |
| Mean for virulence genesc | 10.7 | 9.7 | 10.1 | |||
a
Boldface data indicate statistical significance.
b
For the avian versus human strains. For each comparison, a P value of <0.05 was considered statistically significant, and a P value of >0.05 was considered not statistically significant.
c
Range, 6 to 13.