Table 3

Distribution of aggregate virulence gene scores among 6 groups of extraintestinal E. coli isolates

Study groupVirulence score, median (range)aP valueb
ST131 (FQ-R)9 (8–12)
ST131 (FQ-S)11 (8–12)
Non-ST131 (FQ-R)7 (3–13)0.004
Non-ST131 (FQ-S)8 (2–17)
Classic ExPEC12 (6–17)0.01
ST131 case reports10 (9–11)
  • a Virulence score is the number of virulence-associated genes detected in each isolate, adjusted for multiple detection of the pap (P fimbriae), sfa/foc (S and F1C fimbriae), and kps II (group 2 capsule) operons.

  • b P values versus all other isolates (as calculated using the Mann-Whitney U test) are shown where P < 0.05.