Table. Phenotypic and genotypic traits of Vibrio cholerae O1 clinical strains isolated from northern India, 2002–2007*.

Year of isolation or type of strain	Phenotypic tests					PCR amplicons
	VP	Polymyxin B (50 U) susceptibility	CCA	Sheep erythrocyte hemolysis		tcpA	ctxB (MAMA-PCR)	rstR
2002 (n = 20)	+	Resistant	+	+		E	E	E
2003 (n = 4)	+	Resistant	+	+		E	E	E
2004 (n = 19)	+	Resistant	+	+		E	E	E
2007 (n = 26)	+	Resistant	+	+		E	E + C (n = 21)†	E
Environmental (n = 1)	+	Resistant	+	+		E	E + C	E
Classical 569B	–	Sensitive	–	–		C	C	C
El Tor N16961	+	Resistant	+	+		E	E	E
Hybrid NICED, India	+	Resistant	+	+		E	C	E + C

*VP, Voges-Proskauer; CCA, chick cell agglutination; MAMA, mismatch amplification mutation assay; +, positive; –, negative; E, El Tor type; C, classical type; NICED, National Institute of Cholera and Enteric Diseases, Kolkata, India.
†Remainder had ctxB of El Tor type.