Comparative Antibacterial Activity of Synthetic N,S-Heterocyclic Derivatives, MgO Nanoparticles, and Glycine on Zoonotic Vibrio fluvialis

Background: Vibrio fluvialis is an emerging zoonotic pathogen that its antibiotic‑resistant strains are rapidly expanding. Discovering new antibacterial agents is one way to control it. 
Aims and Objectives: In this research, inhibitory potentials of glycine, magnesium oxide nanoparticles (NPs), and some synthesized thiazole, imidazolidine‑2‑thione, and tetrahydropyrimidine‑2‑thione derivatives were studied against V. fluvialis in an in vitro manner. 
Materials and Methods: Thiazoles were prepared through Hantzsch reaction. Cyclic thioureas were synthesized from the reaction of diaminoalkanes and carbon disulfde. MgO NPs were created in 23.7–25.7 nm by sol–gel processing. Antibacterial properties of all compounds as inhibition zone diameter, the minimum inhibitory concentration, and the minimum bactericidal concentration values were assessed through both disk diffusion and broth microdilution methods. 
Results: No inhibitory activity on V. fluvialis was observed with MgO NPs and glycine. Among thiazole derivatives, only compound 7e could effciently block the growth of this pathogen. All thioureas except derivative 6c showed antibacterial properties. The best results belonged to imidazolidine‑2‑thione 7a. 
Conclusion: Significant inhibitory potentials were observed with some synthetic thiazoles and cyclic thioureas. If antibacterial activates of these heterocycles are proved on resistant strains and their toxic effects are desirable, an important step will be taken in the introduction of these new antibacterial agents.