TABLE 3.

Phenotypic assessment of the wild-type HBL⁺ strain (MGBC145) and the isogenic HBL⁻ mutant (CJ145-1.1)

Strain	Phenotypic assay
	Hemolytic titera	Discontinuous hemolytic zoneb	Vascular permeabilityc	Sphingomyelinased (mean ± SD)	Phospholipase Ce	Proteasef
HBL+	1:8	Yes	Yes	0.023 ± 0.007	Yes	Yes
HBL−	1:32	No	No	0.036 ± 0.003	Yes	Yes

^aHemolytic assay of filtered supernatants of 18-h B. cereus cultures. A twofold difference in titer was considered significant. 

^bPresence or absence of a discontinuous hemolytic zone surrounding isolated B. cereus colonies on 2.5% sheep erythrocyte agar (6). The results of this assay are depicted in Fig. 3A. 

^cPresence or absence of bluing, necrotic foci following intradermal injection of 50 μl of concentrated B. cereus culture supernatants. The results of this assay are depicted in Fig. 3B. 

^dChromogenic TNPAL-sphingomyelinase assay (14). Values represent the OD₃₃₀ of filtered supernatants of 18-h B. cereus cultures (values represent two separate duplicate assays). Values were not significantly different (P = 0.154, Student’s t test). 

^ePresence or absence of turbidity surrounding isolated colonies of B. cereus on egg yolk agar (14). 

^fPresence or absence of a proteolytic zone surrounding isolated colonies on casein agar.