In vitro activity of salicylamide derivatives against vancomycin-resistant enterococci

Bioorg Med Chem Lett. 2018 Jul 1;28(12):2184-2188. doi: 10.1016/j.bmcl.2018.05.011. Epub 2018 May 14.

Abstract

A series of 13 salicylamide derivatives was assessed for antibacterial activity against three isolates of vancomycin-resistant Enterococcus faecalis (VRE) and Enterococcus faecalis ATCC 29212 as a quality standard. The minimum inhibitory concentration was determined by the broth microdilution method with subsequent subcultivation of aliquots to assess minimum bactericidal concentration. The growth kinetics was established by the time-kill assay. Ampicillin, ciprofloxacin, tetracycline and vancomycin were used as the reference antibacterial drugs. Three of the investigated compounds showed strong bacteriostatic activity against VRE (0.199-25 µM) comparable to or more potent than ampicillin and ciprofloxacin. In addition, these compounds were tested for synergistic effect with vancomycin, ciprofloxacin and tetracycline, while 5-chloro-2-hydroxy-N-[4-(trifluoromethyl)phenyl]benzamide showed the highest potency as well as synergistic activity with vancomycin against VRE 368. Screening of the cytotoxicity of the most effective compounds was performed using human monocytic leukemia THP-1 cells, and based on LD50 values, it can be stated that the compounds have insignificant toxicity against human cells.

Keywords: Antibacterial activity; Cytotoxicity; Enterococcus; Salicylamides; Time-kill assay.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / chemistry
  • Anti-Bacterial Agents / pharmacology*
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Dose-Response Relationship, Drug
  • Enterococcus faecalis / drug effects*
  • Humans
  • Microbial Sensitivity Tests
  • Molecular Structure
  • Structure-Activity Relationship
  • Vancomycin / chemistry
  • Vancomycin / pharmacology*
  • Vancomycin-Resistant Enterococci / drug effects*

Substances

  • Anti-Bacterial Agents
  • Vancomycin