Tehran University of Medical Sciences Journal of Medical Bacteriology 2251-8649 4 5-6 2015 12 15 7 12 EN Behzad Ghasemi Faculty of Veterinary Medicine, University of Zabol, Zabol, Iran. Hamid Beyzaei Department of Chemistry, Faculty of Sciences, University of Zabol, Zabol, Iran. Seyed Hadi Hashemi Faculty of Veterinary Medicine, University of Zabol, Zabol, Iran. Hamidreza Majidiani Department of Medical Parasitology and Entomology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran. 2017 01 11 2017 01 11 Background: Escherichia coli is one of the important pathogens in human with global importance. Because of the necessity for identification and the use of novel antibacterial compounds against E. coli, in this present study we focused on the antibacterial effects of synthesized thiazole, imidazole and tetrahydropyridine derivatives on E. coli.  Methods: For evaluation of antibacterial effect, the disk diffusion method was applied to measure the growth inhibition zone diameter and broth micro-dilution was performed to determine the minimum inhibitory concentration (MIC).  Results: Assessing the antibacterial effect showed that only 6d derivative of thiazole had inhibitory effect on E. coli and the other thiazole, imidazole and tetrahydropyridine derivatives lacked any inhibitory result on this organism. The inhibitory effect of 6d derivative of thiazole was MIC=125 and growth inhibition zone diameter of 16±0.1.  Discussion: The antibacterial effect of thiazole, imidazole and tetrahydropyridine derivatives differs from each other and chemical linkages such as oxygen to thiazole ring in 6d derivative, could have reinforced this effect. The next step is determination of the toxicity and therapeutic effects in the laboratory animals. https://jmb.tums.ac.ir/index.php/jmb/article/view/242 https://jmb.tums.ac.ir/index.php/jmb/article/download/242/176