TABLE 1.

Analysis of 46 strains of TCP-positive V. cholerae belonging to different serogroups for production of CTXΦ and VPIΦ particles

Strain(s)	No. of strains analyzed	Serogroup and/or biotype	Presence of genes							Production of phages in supernatantb
			tcpAa	tcpI	toxTa	acfB	rstR	ctxA	zot	VPIϕ	CTXΦc
Clinical isolates
S-224, S-262, L-351, L-262, O395, AE-2882	6	O1 classical	C	+	+	+	+	+	+	−	−
SA317, SA406, SA508	3	O1 El Tor	E	+	+	+	−	−	−	−	−
G-755, N-16961, P-27457, AM-13860, AM-11726, AF-1471, AP-13547, AP-13530, AM-11706	9	O1 El Tor	E	+	+	+	+	+	+	−	+
P-28108, P-27821, AL-12890	3	O1 El Tor	E	+	+	+	+	+	+	−	−
AI-1836	1	O139	E	+	+	+	+	+	+	−	−
AL-11089, AP-32541, AK-17334, AR-1432, AR-1468, AL-12077	6	O139	E	+	+	+	+	+	+	−	+
Surface water isolates
EV-02, EV-11, 102V138	3	O1 El Tor	E	+	+	+	+	+	+	−	+
SB-Lake, 224V541, Env-91	3	O139	E	+	+	+	+	+	+	−	+
SCE4, SCE359	2	O8	C	+	+	+	−	−	−	−	−
SCE223, SCE354	2	O27	Env	+	+	+	+	+	+	−	−
SCE225, SCE226, SCE227	3	O35	C	+	Env	+	+	−	−	−
SCE256, SCE264	2	O42	C	+	Env	+	+	−	−	−	−
SCE263	1	O10	C	+	Env	+	+	+	−	−	−
SCE340, SCE341	2	O69	E	+	Env	−	−	−	−	−	−

^aEnv,+, present; −, not present; new alleles of the tcpA or toxT genes, which are different from those normally found in epidemic strains; C, classical tcpA type gene present; E, El Tor type tcpA gene present.

^bMost strains carried other unidentified phage genomes, as shown by analysis of the total nucleic acids extracted from phage preparations of the strains, but these nucleic acids did not hybridize with probes for CTXΦ or VPIΦ. Strains were grown in the presence of mitomycin C (20 ng /ml) for phage induction (see text for details).

^cCTXΦ was produced irrespective of whether strains were grown at 30 or 37°C.