Table 5

Aggregate virulence and antimicrobial resistance scores of 200 selected extended-spectrum-β-lactamase-producing Escherichia coli isolates (collected in 2000 to 2009) in relation to ST131 and blaCTX-M-15 status

Type of scoreScore median (range)P valuea
ST131 M15 (group 1; n = 50)ST131 M15+ (group 2; n = 50)ST131+ M15 (group 3; n = 50)ST131+ M15+ (group 4; n = 50)Group 1 vs 2Group 3 vs 4Group 1 vs 3Group 2 vs 4
Virulence4 (0-18)4 (1-10)10 (2-13)10 (6-14)0.01< 0.001< 0.001
Resistance13 (4-19)15 (7-19)12 (4-19)13 (9-17)0.040.003
  • a P values (Mann-Whitney U test) are shown where P < 0.05.