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, %)
AB1B2CDEF
(n=25)(n=34)(n=2)(n=9)(n=8)(n=2)(n=2)
ExPEC-associated genes
papAH2 (8.0)2 (5.9)3 (33.3)
papC2 (8.0)2 (5.9)3 (33.3)
papEF1 (11.1)
yfcv2 (100)
hlyA1 (4.0)12 (35.3)1 (50)1 (12.5)
vat1 (50)2 (100)
fyuA6 (24.0)8 (23.5)1 (50)6 (66.7)2 (100)
iutA3 (12.0)5 (14.7)1 (50)5 (55.6)1 (12.5)2 (100)
 KpsMII1 (50)1 (12.5)
 PAI1 (50)
traT14 (56.0)27 (79.4)2 (100)8 (88.9)4 (50)2 (100)2 (100)
 Virulence factor score (median, range)1, 0–42, 0–55, 2–83, 0–60.5, 0–31, 1–14, 4–4
IPEC-associated genes
stx1a2 (8.0)
subAB1 (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.