Shahrekord University of Medical Sciences Future Natural Products 2783-4662 4 1 2018 01 31 Investigating the antimicrobial effects of Withania somnifera methanol extract prepared by ultrasonic waves on omit Klebsiella pneumonia 47 57 EN Mohammad Amin Masshady Javad Roustakhiz Saphora Bazi Mehdi Hassanshaian Journal Article 2017 02 10 2017 03 27 Background and aims: 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. K. pneumonia is a bacterial negative intestinal bacillus and a member of Enterobacteriaceae family. This paper aims at investigating the antimicrobial effects of the methanol extract of wind cheese prepared by ultrasonic waves on the K. Pneumonia. Methods: All 12 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 2013 and 2014. In this study, the extract of W. somnifera obtained by ultrasonic waves. Then the minimum inhibitory concentrations and minimum bactericidal concentration were investigated to characterize the antibacterial activities of this extract. Results: The result showing that plant extracts from W. somnifera had inhibitory effect against K. pneumoniae. The MIC values were also determined against all the tested bacteria. The highest MIC values of extract were found to be 5mg/ml against K. pneumoniae and four of MIC value for K. pneumoniae was 2.5 mg/ml. (p<0.005). Conclusion: The obtained results showed that extraction by using ultrasonic method improved the efficiency and amount of the antimicrobial effects of the plant. So, ultrasonic waves can be used as a stimulus for increasing the antimicrobial effects of the plant.