Table 1.

Lethality for mice according to B2 phylogenetic group status and number of virulence factorsa

No. of virulence factorscProportion of strains lethal to miceb
non-B2d(n = 45)B2d (n = 37)Total (n = 82)
00/300/30/33
11/71/22/9
26/86/812/16
>2(none)24/2424/24
  • a Data from reference 1.

  • b Lethal to one or more mice.

  • c Factors including hemolysin, MRHA, K1 antigen, sfa/foc, pap, hly, andibe10 (not afa and aer).

  • d P > 0.10 for proportion lethal to mice for phylogenetic group B2 versus non-B2 (i.e., A, B1, and D) strains within each virulence factor stratum (no, one, or two virulence factors).