Investigation of the antibacterial effect of venom of the Iranian snake Cerastes cerastes Behrooz Fathi1, Abdoula Jamshidi1, Atena Jami al ahmadi1, Azam Mohamadi1 and Abbase Zare2 1 School of Veterinary Medicine, Ferdowsi University of Mashhad-Iran1 2 Razi Vaccine and Serum Research Institute, Tehran- Iran2 Introduction and objectives: The phenomenon of resistance is one of the major problems to fight against infection diseases because the patterns of resistance are constantly changing. In addition, the resistance of bacteria to current antibiotics is increasing. Therefore, discovery of new effective antibacterial agents is continuously necessary. Snake venoms contain a great variety of biologically active proteins. Although some venoms and their isolated compounds have been shown to have antibacterial properties, most have not been investigated for such activity. Cerastes cerastes is one of the most venomous snakes in the world and has potent and haematotoxic venom that destroys endothelial cells and causes haemorrhagia. In this study the antibacterial activity of this snake venom against five different bacteria including: Staphylococcus aureus, Meticillin resistance staphylococcus aureus (MRSA), Bacillus subtilis, Listeria monocytogenes, Salmonella typhimurium and E.coli O157.H7), has been investigated. . Materials and Methods: Lyophilized venom was a kind gift of the Razi Institute. All the mentioned bacteria were purchased from Mast International Inc-UK. We used Disc-diffusion and minimum inhibitory concentration (MIC) methods for this investigation. In Disc diffusion method we used 20µl/Disc of 100µg/ml concentration of venom and as positive control used different standard antibiotics. The (MIC) was studied by series of different concentration including 160, 80, 40, 20, 10, 5, 2.5, and 1.25µg/ ml which add 20µl of each dilution to each test tube and then 107 CFU of bacteria added to each test tube. In this method, different standard antibiotics were used as positive control and Tris buffer as negative control. . Results: The results of this study showed the strong effect of Cerastes cerastes venom on Staphylococcus aureus, Meticillin resistance staphylococcus aureus (MRSA), Listeria monocytogenes and E.coli while it has a moderate effect on Salmonella typhimurium. The venom has lack of antibacterial effect against Bacillus subtilis. The minimum inhibitory concentration (MIC) has been determined for those bacteria which showed sensitivity in Disc-diffusion test. . Conclusion: We concluded that the venom of Cerastes cerastes venom has effective proteins to be responsible for its antibacterial activity for some specific strains and need to be recognized and isolate. Also to determine whether Cerastes cerastes venom can inhibit other pathogens, further studies are needed using a wider spectrum of Gram-positive and Gram-negative bacteria and also other concentrations of this venom. Also it is concluded that snake venom could represent a powerful tool for discovery of novel and effective antibacterial drugs to fight resistant bacteria. .

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