Comparison of antibacterial effects of silver nanoparticles with thiazole, imidazoline and tetrahydropyridine derivatives against hospital gram negative bacterial pathogen

Progress of drug resistance in nosocomial gram negative bacteria is a serious threat to the health of patients, personnel of treatment sections and to public hygiene in total. Identifying and using novel antibacterial compounds such as thiazole, imidazole and tetrahydropyridine derivatives as well as silver nanoparticles could be a significant solution to this issue. In this regard, we accomplished the study and comparison of antibacterial effect of thiazole, imidazole and tetrahydropyridine derivatives as well as silver nanoparticles on three gram negative bacteria, Proteus mirabilis, Acinetobacter baumannii and Shigella dysenteriae.
To evaluate the antibacterial effect, the disk diffusion method was applied to measure the growth inhibition zone diameter and broth microdilution was performed to determine the minimum inhibitory concentration (MIC).
Results showed that thiazole, imidazole and tetrahydropyridine derivatives as well as silver nanoparticles had no inhibitory effect on Acinetobacter baumannii. Also there was no inhibitory effect from imidazole and tetrahydropyridine compounds beside 6a-c derivative of thiazole on bacteria. In this study the halo diameter of 17.3 and 18.5 mm and MIC of 125 and 62.5 µg/ml were recorded for inhibitory effect of 6d derivative of thiazole on Proteus mirabilis and Shigella dysenteriae, respectively. Furthermore, the silver nanoparticle had inhibitory effect with halo diameter of 13.4 and 15.2 mm and MIC of 1125 and 562.5 µg/ml on Proteus mirabilis and Shigella dysenteriae, respectively.
In this study the antibacterial potency of thiazole derivative was proved in comparison to silver nanoparticle.