Study of the inhibitory effects of n-heterocycles, magnesium oxide nanoparticles, nisin and poly-l-lysine on Enterobacter aerogenes (hospital pathogen)

Enterobacter aerogenes (E. aerogenes) is one of the causes of hospital-acquired infections, which its standard strains quickly become resistant to the antibiotics. The discovery of new inhibitory agents against this pathogen is constantly expanding. In this study, the inhibitory effects of several synthetic chemical compounds including magnesium oxide nanoparticles and thiazole, imidazolidine and tetrahydropyrimidine derivatives and natural compounds including nisin and poly-L-lysine were evaluated against E. aerogenes.

The project is an experimental study. Solutions of all compounds with a specific initial concentration were prepared in 10% DMSO. Antibiogram tests were performed by disc diffusion and broth micro dilution methods according to CLSI guidelines.

Thiazole and tetrahydropyrimidine derivatives, magnesium oxide nanoparticles, nisin and poly-L-lysine had no inhibitory effects on E. aerogenes. Only, imidazolidines 10a and 10c were effective against E. aerogenes with Inhibition Zone Diameter (IZD) = 6.12 and 11.52 mm, Minimum Inhibitory Concentration (MIC) = 1024 and 256 μg/ml, and Minimum Bactericidal Concentration (MBC) = 2048 and 512 μg/ml, respectively.

The inhibitory effects of imidazolidines10a and 10c were proved on the standard strains of E. aerogenes. Design and synthesis of new and more effective derivatives having imidazolidine skeletons can be considered in future studies.