Evaluation of toxicity of iron, chromium and cadmium on Bacillus cereus growth

ABSTRACT

High concentration of iron and other trace elements could restrict bacterial growth and modify their metabolic pattern as well. However, this study aimed to find out the influence of iron, chromium, cadmium and synergism or antagonism between these elements on the growth of a gram positive bacterium. In a series of experiments, Bucillus cereus was cultured in a nutrient broth which supplemented with Fe[+2], Fe[+3], Cr[+3], Cd[+2] separately, or in combination with each other, at 37°C for 5 hours. Bacterial growth was measured every half - hour, using spectrophotometer. The results indicated that bacterial growth rate reduced in the presence of 0.5 mM/L concentration of Fe[+2] or Fe[+3], in comparison with control and the growth of bacteria was inhibited by 1 mM/L concentration of iron. The results also revealed that Fe [III] as well as Fe [II] was toxic for bacteria. Chromium had partial inhibitory effects on the growth of bacteria and cadmium was very toxic. Cr[+3] and Cd[+] had antagonistic effect with iron on the growth of bacteria. Data obtained here provide a potentially interesting conceptual advance in toxic effects of trace elements on pathogenic bacteria