TABLE 2.

Logistic regression analysis of multiple virulence factors and B2 status as predictors of mouse lethality^a

Lethality criterion	Multiple virulence factorsb		B2 phylogenetic group
	RRc	P	RR	P
≥1 mouse (model 1)	82	<0.001	6	0.04
All 10 mice (model 2)	31	0.003	2	0.33
Accelerated lethalityd (model 3)	37	0.001	3	0.11

^aResults are based on data from reference 1. 

^bTwo or more factors including hemolysin, MRHA, K1 antigen, sfa/foc, pap, hly, and ibe10 (not afa and aer). 

^cRR, relative risk. 

^dAccelerated lethality as indicated by + in the column labeled “Lethality in mice” of Table 1 of reference 1.