Table 1.

Number of bacteria and prevalence on bacterial types obtained in the lowest concentrations of heavy metals

Nutrient agar with:	CSS			UHS
	cfu/mL 5.3x105* (%)	% Bacteria		cfu/mL 4.2x105* (%)	% Bacteria
		G +	G -		G +	G -
K2Cr2°7 [60]	5.3x103 (1.0)	71.5**	28.5	5.5x103 (1.3)	68.4**	31.6
AgNO3 [20]	2.1x103 (0.4)	9.3	90.7***	2.1x103 (0.5)	48.4	51.6***
HgCl2 [60]	1.1x104 (2.0)	10.7	89.3	1.7x104 (4.1)	5.2	94.8

Abbreviations: CSS, Chemistry school; UHS, University hospital; G+, Gram positive; G-, Gram negative.

[ ]: μg/mL.

^*mean total count of cfu/mL obtained in media without metal.

^**100% in the concentration of 310 μg/mL of the metal.

^***100% in the concentration of 35 μg/mL of the metal.