Evaluation of Toxicity of Iron, Chromium and Cadmium on Bacillus cereus Growth

Document Type : Original Article


Para-medicine Faculty, Babol University of Medical Sciences, Babol, Iran


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.
Materials and Methods
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.


1.Yamini H,  Shrivastava S, Devaraj N, Balachandran UN. A Schiff base complex of chromium (III): an efficient inhibitor for the pathogenic and invasive potential of Shigella dysenteriae. J Inorg Biochem 2004; 98:387-392.
2. Neilands JB. Iron and its role in microbial physiology. In: Neilands J B. (ed.). Microbial iron metabolism. New York: Academic Press Inc; 1974. 3-34.
3. Sussman M. Iron and infection. In Jacobs, Worwood AM. (ed.). Iron in biochemistry and medicine. London: Academic Press Inc; 1974. 649-679.
4. Andrews SC, Robinson AK, Rodríguez-Quiñones F. Bacterial iron homeostasis.  FEMS Microbiol Rev 2003; 27: 215-237.
5. Köster W. ABC transporter-mediated uptake of iron, siderophores, heme and vitamin B12. Res Microbiol 2001; 152: 291–301.
6. Velayudhan J,  Hughes NJ, McColm AA,  Bagshaw J, Clayton CL, Andrews SC, Kelly DJ. Iron acquisition and virulence in Helicobacter pylori: a major role for FeoB, a high-affinity ferrous iron transporter. Mol Microbiol 2000; 37: 274–286.
7. Marlovits TC, Haase W, Herrmann C, Aller SG, Unger VM. The membrane protein FeoB contains an intramolecular G protein essential for Fe (II) uptake in bacteria. Proc Natl Acad Sci. 2002; 99: 16243–16248.
8. Andrews SC. Iron storage in bacteria. Adv Microb Physiol 1998;40: 281–351.
9. Litwin CM, Calderwood SB. Role of iron in regulation of virulence genes. Clin Microbiol Rev 1993; 6: 137–149.
10.Calderwood SB, Mekalanos JJ. Iron regulation of Shiga-like toxin expression in Escherichia coli is mediated by the fur locus. J Bacteriol 1987; 169: 4759–4764.
11. Gelvan D. Enhancement of adriamycin toxicity by iron chelates is not a free radical mechanism. Biol Trace Elem Res 1997; 56: 295-309.
12. Chamnongpol S, Dodson W, Cromie MJ, Harris ZL , Groisman EA.12 Fe (III) mediated cellular toxicity. Mol Microbiol 2002; 45: 711-719.
13. Slepenkin A,  Enquist PA, Hägglund U, de la Maza LM, Elofsson M, Peterson EM. Reversal of the Antichlamydial Activity of Putative Type III Secretion Inhibitors by Iron. Infect Immun 2007; 75:3478-89. 
14. Simonet M, Berche P, Fauchere JL, Veron M. Impaired resistance to Listeria monocytogenes in mice chronically exposed to cadmium. Immunology 1984; 53:155-63.
15. Tornabene TG, Edwards HW. Microbial uptake of lead. Science 1972; 176: 1334-1335.
16. Juturu V, Komorowski JR. Chromium supplements, glucose, and insulin responses. Am J Clin Nutr 2003; 78: 192-3.
17. Ryan GJ, Wanko NS, Redman AR Cook CB. Chromium as adjunctive treatment for type 2 diabetes. Ann Pharmacother 2003; 37: 876-85.
18. Sultana N, Arayne MS, Sabr R. Erythromycin synergism with essential and trace elements. Pak J Pharm Sci  2005; 18: 35-9.
19. Arayne, M S, Sultana N, Zaman M K, Faroog A.Synthesis and characterization of gliclazide complexes of magnesium, calcium, chromium, manganese, iron, nickel, copper, zinc and cadmium salts. Pak J Pharm Sci  2005; 18: 35-40
20. Epand RM, Vogel HJ. Diversity of antimicrobial peptides and their mechanisms of action. Biochim Biophys Acta 1999; 1462: 11–28.
21. Vaara M. Agents that increase the permeability of the outer membrane. Microbiol Rev 1992; 56: 395–411.
22. Braun V.Avoidance of iron toxicity through regulation of bacterial iron transport. Biol Chem1997; 378: 779-786.
23. Bruins MR, Kapil S, Oehme FW. Microbial resistance to metals in the environment. Ecotoxicol Environ Saf 2000; 45: 198–207.
24. Laddaga RA, Silver S.Cadmium uptake in Escherichia coli K-12. J Bacteriol 1985; 162: 1100-5.
25. Prozialeck WC, Wellington DR, Mosher TL, Lamar PC, Laddaga RA. The cadmium-induced disruption of tight junctions in LLC-PK1 cells does not result from apoptosis. Life Sci 1995; 57:199-204.
26. Stern NJ, Kazmi SU, Roberson BS, Ono K, Juven BJ. Response of Campylobacter jejuni to combinations of ferrous sulphate and cadmium chloride. J Appl Bacteriol 1988; 64: 247-55.
27. Valenti P, Stasio A, Seganti L, Mastromarino P, Sinibaldi L, Orsi N. Capacity of Staphylococci to grow in the presence of ovotransferrin or CrCl3 as a character of potential pathogenicity. J Clin Microbiol 1980; 11: 445-447.