Table 1.
Distribution of virulence factors among the phylogenetic groups of 82 Escherichia coli causing bovine mastitis
| Gene or marker* | Prevalence by phylogenetic group (n, %) | ||||||
| A | B1 | B2 | C | D | E | F | |
| (n=25) | (n=34) | (n=2) | (n=9) | (n=8) | (n=2) | (n=2) | |
| ExPEC-associated genes | |||||||
| papAH | 2 (8.0) | 2 (5.9) | – | 3 (33.3) | – | – | – |
| papC | 2 (8.0) | 2 (5.9) | – | 3 (33.3) | – | – | – |
| papEF | – | – | – | 1 (11.1) | – | – | – |
| yfcv | – | – | 2 (100) | – | – | – | |
| hlyA | 1 (4.0) | 12 (35.3) | 1 (50) | – | 1 (12.5) | – | – |
| vat | 1 (50) | – | – | – | 2 (100) | ||
| fyuA | 6 (24.0) | 8 (23.5) | 1 (50) | 6 (66.7) | – | – | 2 (100) |
| iutA | 3 (12.0) | 5 (14.7) | 1 (50) | 5 (55.6) | 1 (12.5) | – | 2 (100) |
| KpsMII | – | – | 1 (50) | – | 1 (12.5) | – | – |
| PAI | – | – | 1 (50) | – | – | – | – |
| traT | 14 (56.0) | 27 (79.4) | 2 (100) | 8 (88.9) | 4 (50) | 2 (100) | 2 (100) |
| Virulence factor score (median, range) | 1, 0–4 | 2, 0–5 | 5, 2–8 | 3, 0–6 | 0.5, 0–3 | 1, 1–1 | 4, 4–4 |
| IPEC-associated genes | |||||||
| stx1a | 2 (8.0) | – | – | – | – | – | – |
| subAB | – | 1 (2.9) | – | – | – | – | – |
*aggR, afa, eae, LT, sfa, STh, STp and stx2 genes were not identified in any of the isolates.
–, not detected; ExPEC, extraintestinal pathogenic E. coli;fyuA, ferric yersiniabactin uptake protein; hlyA, haemolysin; IPEC, intestinal pathogenic E. coli; iutA, aerobactin siderophore receptor; KpsMII, group 2 polysaccharide capsule; PAI, right-hand terminus of pathogenicity island; papAH, pyelonephritis-associated major pilin protein; papC, outer membrane usher protein; papEF, fimbrial protein subunit; stx1a, Shiga toxin subunit; subAB, subtilase cytotoxin; traT, lipoprotein involved in serum resistance; vat, vacuolating autotransporter toxin; yfcv, major subunit of a chaperone-usher fimbria.