Effect of phenylalanine-arginine beta-naphthylamide on minimal inhibitory concentration of antibiotics in the case of salmonella enterica cells

Abstract

Resistance to antibiotics is the very common problem in medicine. It is important to understand the mechanisms of multidrug resistance in bacteria. We focused our study on efflux pump system using method of microdilutions. We used Salmonella enterica SL1344 (WT), L664 and ΔacrB strains to determine influence of phenylalanine-arginine β-naphthylamide (PAβN) on MICs of ampicillin, chloramphenicol and tetracycline. PAβN is very popular inhibitor of RND-type efflux pumps. It is toxic for bacterial cells only at high concentrations. We showed that low inactive concentrations of antibiotics can inhibit bacterial growth in combination with PAβN. Our results indicate that inhibitory activity of PAβN depends on the initial bacterial cell concentration. Such results suggest intensive binding of PAβN by the cells.