Evaluation of Antibacterial Activity of Withania somnifera Leaf Extracts against Antibiotic-Resistant Isolates of Klebsiella pneumoniae

Abstract

Background: Herbal medicines has been a major remedy in traditional medical systems from thousands of years and made a great contribution in maintaining human health and in preventing many infectious diseases. Objectives: The aim of this study was to evaluate antibacterial activity of leaf extracts of Winter Cheery (Withania somnifera) against antibiotic-resistant isolates of Klebsiella pneumoniae isolated from the urinary tract infection patients. Materials and Methods: All 30 isolates of K. pneumoniae isolated from urine culture of hospitalized patients (Amir al-Mu'minin Hospital, Zabol, southeastern of Iran) suffered from urinary tract infection during the years 2011 and 2012. In this study, the extract of W. somnifera obtained by rotary evaporator. Then the minimum inhibitory concentrations were investigated to characterize the antibacterial activities of this extract. Results: The isolates of K. pneumoniae were resistance to four of the agents including ceftazidime (60% of isolates) cefixime (60% of isolates), erythromycin (66.6% of isolates). The highest MIC values of extract were found to be 250 ppm against K. pneumoniae and MIC values for K. pneumoniae were 63 ppm. Conclusions: This study confirmed the antimicrobial potential of investigated plants and their usefulness in treatment of resistant isolates of K. pneumoniae.