TABLE 2.
Distribution of virulence genes among the 42 isolates, the largest phylogenetic groups, and relevant ST clonal complexesb
| Virulence gene or E. coli type | Product(s) | No. (%) of isolates |
P valuea for phylogroup A/ST10 clonal complex vs phylogroup A/non-ST10 clonal complex | |||||
|---|---|---|---|---|---|---|---|---|
| Total (n = 42) | Phylogroup A (n = 15) | Phylogroup B1 (n = 18) | Phylogroup C (n = 7) | Phylogroup A/ST10 clonal complex (n = 8) | Phylogroup A/non-ST10 clonal complex (n = 7) | |||
| Virulence genes | ||||||||
| Adhesins | ||||||||
| fimH | d-Mannose-specific adhesin of type 1 fimbriae | 42 (100) | 15 (100) | 18 (100) | 7 (100) | 8 (100) | 7 (100) | |
| papEF | Pilus associated with pyelonephritis (P fimbriae) | 11 (26) | 5 (33) | 4 (22) | 0 | 5 (63) | 0 | 0.0256 |
| papG | P fimbriae carrying Gal(α1-4) Gal-specific PapG adhesin at its distal end | 3 (7) | 0 | 2 (11) | 0 | 0 | 0 | |
| papA | Major structural subunit of the P fimbrial shaft | 3 (7) | 0 | 3 (17) | 0 | 0 | 0 | |
| papC | Pilus assembly; central region of the pap operon | 4 (10) | 0 | 3 (17) | 0 | 0 | 0 | |
| sfa/focDE | Central region of the sfa and foc operons | 1 (2) | 0 | 1 (6) | 0 | 0 | 0 | |
| afa/draBC | Dr antigen-specific adhesin operons (AFA, Dr, F1845) | 0 | 0 | 0 | 0 | 0 | 0 | |
| Toxins | ||||||||
| cnf1 | Cytotoxic necrotizing factor 1 | 0 | 0 | 0 | 0 | 0 | 0 | |
| cdtB | Cytolethal distending toxin | 0 | 0 | 0 | 0 | 0 | 0 | |
| sat | Secreted autotransporter | 0 | 0 | 0 | 0 | 0 | 0 | |
| hlyD | Alpha-hemolysin | 0 | 0 | 0 | 0 | 0 | 0 | |
| hlyF | Hemolysin F | 37 (88) | 12 (80) | 16 (89) | 7 (100) | 8 (100) | 4 (57) | |
| astA | Enteroaggregative E. coli heat-stable toxin (EAST1) | 12 (29) | 7 (47) | 4 (22) | 0 | 7 (86) | 0 | 0.0014 |
| tsh | Temp-sensitive hemagglutinin-serine protease | 12 (29) | 2 (13) | 4 (22) | 6 (86) | 2 (25) | 0 | |
| stx1 | Shiga toxin 1 | 0 | 0 | 0 | 0 | 0 | 0 | |
| stx2 | Shiga toxin 2 | 0 | 0 | 0 | 0 | 0 | 0 | |
| Siderophores | ||||||||
| fyuA | Yersinia siderophore receptor (ferric yersiniabactin uptake) | 6 (14) | 0 | 3 (17) | 3 (43) | 0 | 0 | |
| iutA | Ferric aerobactin receptor (iron uptake; transport) | 32 (76) | 9 (60) | 15 (83) | 6 (86) | 8 (100) | 1 (14) | 0.0014 |
| iroN | Novel catecholate siderophore receptor | 33 (79) | 9 (60) | 15 (83) | 7 (100) | 8 (100) | 1 (14) | 0.0014 |
| ireA | Iron-regulated element (novel siderophore receptor) | 6 (14) | 0 | 5 (28) | 0 | 0 | 0 | |
| Protectins | ||||||||
| kpsM II | Group II capsule | 2 (5) | 1 (7) | 0 | 0 | 0 | 1 (14) | |
| kpsM II-K2 | K2 subgroup II capsule | 1 (2) | 1 (7) | 0 | 0 | 0 | 1 (14) | |
| kpsM II-K5 | K5 subgroup II capsule | 1 (2) | 0 | 1 (6) | 0 | 0 | 0 | |
| kpsM II-K1 | K1 subgroup II capsule | 0 | 0 | 0 | 0 | 0 | 0 | |
| kpsM III | Group III capsule | 10 (24) | 7 (47) | 2 (11) | 0 | 7 (86) | 0 | 0.0014 |
| cvaC | Colicin V from serum resistance-associated plasmids | 20 (48) | 1 (7) | 12 (67) | 6 (86) | 1 (13) | 0 | |
| iss | Increased serum survival (outer membrane protein) | 36 (86) | 10 (67) | 17 (94) | 7 (100) | 8 (100) | 2 (29) | 0.0070 |
| traT | Surface exclusion, serum survival (outer membrane protein) | 37 (88) | 12 (80) | 17 (94) | 6 (86) | 8 (100) | 4 (57) | |
| Miscellaneous | ||||||||
| ompT | Outer membrane protein (protease) T | 37 (88) | 12 (80) | 16 (89) | 7 (100) | 8 (100) | 4 (57) | |
| ibeA | Invasion of brain endothelium | 1 (2) | 1 (7) | 0 | 0 | 0 | 1 (14) | |
| malX | Pathogenicity-associated island marker | 1 (2) | 1 (7) | 0 | 0 | 1 (13) | 0 | |
| usp | Uropathogenic-specific protein (bacteriocin) | 1 (2) | 1 (7) | 0 | 0 | 0 | 1 (14) | |
| clbB | Hybrid peptide-polyketide synthase (colibactin) | 32 (76) | 12 (80) | 13 (72) | 6 (86) | 6 (75) | 6 (86) | |
| clbN | Nonribosomal synthetase (colibactin) | 0 | 0 | 0 | 0 | 0 | 0 | |
| fliCH7 | H7 flagellin variant | 1 (2) | 0 | 1 (6) | 0 | 0 | 0 | |
| E. coli types | ||||||||
| APEC | 34 (81) | 9 (60) | 17 (94) | 7 (100) | 8 (100) | 1 (14) | 0.0014 | |
| ExPEC | 12 (29) | 6 (40) | 4 (22) | 0 | 5 (63) | 1 (14) | ||
a
P values (by Fisher's exact test) are shown where the P value was <0.05.
b
The mean virulence scores (number of virulence genes detected), adjusted for multiple detections of the pap, sfa/foc, clbB-clbN, and kpsM II operons, were 8.8 (range, 1 to 12) for the total number of isolates and 7.8 (1 to 12) for phylogroup A, 9.1 (4 to 12) for phylogroup B1, 9.7 (6 to 11) for phylogroup C, 10.6 (10 to 12) for phylogroup A/ST10 clonal complex, and 4.6 (1 to 7) for phylogroup A/non-ST10 clonal complex isolates. Virulence scores were compared by use of the Mann-Whitney U test (P < 0.0001).