In vitro activity of the extracts of medicinal plants Ecballium elaterium and Arnebia densiflora, which is endemic to Turkey, was screened against isolated strains of Klebsiella pneumoniae that were resistant in disc diffusion test (trimethoprime-sulfamethoxazol, sulbactam-ampicillin, clavulonat-amoxicillin, ceftriaxone, cefepime, imipenem, ceftazidime, tobramycin, gentamicin, ofloxacin, ciprofloxacin). Broth microdilution susceptibility testing was performed according to the Clinical and Laboratory Standards Institute. The extracts of A. densfilora root bark and E. elaterium leaf, stem and fruit samples were analyzed against the strains of K. pneumoniae at the concentrations range from 128 to 0.0312 ug/mL. This is the first report shows that the extracts of A. densiflora and E. elaterium are effective as much as the antibiotics amoxicillin and ofloxacin against some of the isolated strains of K. pneumoniae (K2, K3, Ks, K6, and KI0) at the concentration of 32 ug/mL. The extracts were active at the concentration of 64 ug/mL onto rest of the strains, which are close to the effective dose of controls as well. However, the activities of all the extracts against standard control strain of K. pneumoniae (RSKK 574) were comparatively better (8 ug/mL) than that of the tested isolated strains of K. pneumoniae, in which the activities varied between 32 to 64 ug/mL.

Keywords: Arnebia densiflora, Aktivite, GSßL, Ecballium elaterium