Antimicrobial activities of thiazole, imidazolidine, tetrahydropyrimidine derivatives and silver/polyvinyl alcohol nanocomposites against selected zoonotic fish bacterial pathogens

Abstract

One of the serious problems faced by health and food security is the spread of drug-resistant zoonotic aquatic bacterial pathogens. For this reason, identification and application of new antibacterial agents are required. In this study, inhibitory effects of thiazole, imidazolidine and tetrahydropyrimidine derivatives and silver/polyvinyl alcohol (Ag/PVA) nanocomposites were evaluated against three important zoonotic fish bacterial pathogens namely Streptococcus iniae, Edwardsiella tarda and Aeromonas hydrophila. Ag/PVA nanocomposite was found to inhibit growth of all tested bacteria, the highest activity was observed against S. iniae with minimum inhibitory concentration (MIC) of 256 µg ml-1 and inhibition zone diameter (IZD) of 10.2 mm. No inhibitory effects were observed with imidazolidines10a-c, tetrahydropyrimidines 10d-e and thiazoles 6a-c. Among heterocyclic compounds, only thiazole derivatives 6d and 8 had inhibitory effects on S. iniae and E. tarda with MIC values of 32-256 µg ml-1 but lacked antibacterial activity against A. hydrophila.