Table 2. Composition and concentrations used in the reactions of the molecular study of V. cholerae strains isolated from water and sediments collected in four estuaries in Ceará, Brazil, between January and April 2009.

Reagents of the reaction*	PCR		Multiplex PCR
	Species-specific gene		Virulence genes
	ompW	ctxAB	tcp	rfbO1	zot
Buffer 10X	20 mM Tris pH 8.4, 50 mM KCl		20 mM Tris pH 8.4, 50 mM KCl
dNTP's (2.5 mM)	0.25 µM		0.25 µM
Primer F (10 µM)	0.4 µM	0.4 µM	0.4 µM	0.4 µM	0.4 µM
Primer R (10 µM)	0.4 µM	0.4 µM	0.4 µM	0.4 µM	0.4 µM
MgCl2 (50 mM)	1.5 mM		1.5 mM
Taq polymerase (500 U)	4 U		4 U
Sample	20-35 ng**		20-35 ng**
Final reaction volume	25 µL		25 µL

^*= water q.s. was added to each reaction;

^**= sample concentration varied from 20 to 25 ng.