TABLE 5.

Assays of clinical non-O1, non-O139 V. cholerae strains to determine their ability to lyse rabbit erythrocytes, extent of motility, formation of biofilm, and cytotoxic effect

Strain/serogroup	Presence or absence of potential virulence genesa					Phenotypes
	TTSSb	tcpAc	ctxA	rtxA	hlyA	Hemolytic titerd	Motility (cm)e	Biofilm assayf	Cytotoxic titerg
SC124/O36	+	+	+	+	+	64	2.9	0.62	128
SC72/ONT	+	+	−	+	+	16	4.1	0.31	256
SC103(a)/O48	+	+	−	+	+	32	5.2	0.78	128
SC113/O23	+	−	−	+	+	64	4.0	0.47	64
SC132/O48	+	+	−	+	+	32	4.2	0.41	128
SC182/O15	+	−	−	+	+	2	3.0	0.20	64
SC191/O48	+	+	−	+	+	16	4.1	0.43	128
SC130/O37	−	−	−	+	+	8	2.6	0.47	2048
SC164/O59	−	−	−	+	+	16	2.4	0.73	512
SC42/ONT	−	−	−	+	−	4	2.6	0.64	32
SC133/O6	−	−	−	+	−	8	3.0	0.58	128
SC65/ONT	−	−	−	−	−	2	2.3	0.25	32
SC108/O113	−	−	−	−	−	2	2.1	0.21	64

^aThe presence (+) or absence (−) of potential virulence genes is shown.

^bPCR-based detection of the TTSS cluster by the presence of vcsC2, vcsN2, vspD, and vcsV2.

^cThe strains possessed the tcpA^Env allele.

^dThe hemolytic titer was defined as the highest dilution of cell-free culture supernatants (BHI, 6 h, 37°C) sufficient to cause 50% lysis of rabbit erythrocytes in 2 h at 37°C. Photometric assay (OD₅₄₀) was used to quantify the percent lysis.

^eThe motility of V. cholerae strains was determined in centimeters and represents the diameter of the culture zone formed on the surface of the plate incubated at 30°C for 15 h.

^fRetention of crystal violet dye by V. cholerae cells that formed the biofilm on a glass surface was estimated at 570 nm.

^gInducing altered morphology in at least 50% HeLa cells was considered the endpoint.