Tehran University of Medical Sciences Journal of Medical Bacteriology 2251-8649 4 1-2 2015 01 17 53 57 EN Mohammad Bokaeian Infectious Diseases and Tropical Medicine Research Center, Zahedan University of Medical Sciences, Zahedan, Iran. Barat Ali Fakheri Department of Plant Breeding and Biotechnology, Faculty of Agriculture, University of Zabol, Zabol, Iran. Nafise Mahdi Nejad Department of Plant Breeding and Biotechnology, Faculty of Agriculture, University of Zabol, Zabol, Iran. Mehdi Hassansahian Departments of Biology, Faculty of Science, Shahid Bahonar University of Kerman, Kerman, Iran. Saeide Saeidi Institute of Agriculture Biotechnology, University of Zabol, Zabol, Iran. 2016 08 08 2016 08 08 Introduction: Due to more resistance of pathogenic bacteria to new and current antibiotics researchers are looking to find the agents of herbal with antimicrobial activities in order to replace chemical drugs. Methods: The herbal extract of Withani somnifera was done by using a rotary vacuum, 20 strains of Pseudomonas aeruginosa were isolated from urinary infections hospitalized patients in city of Zabol hospital. The MIC Withani somnifera were determined by dilution method in various concentrations. Sensitivity of strains to multiple antibiotics was evaluated by standard disk diffusion Kirby-Bauer. Results: The result showed that P. aeruginosa were resistance to 4 of the agents including ampicillin (85%), nitrofurantoin (65%), nalidixic acid (65%), ciprofloxacin (15%) and for 5 strains of Pseudomonas showed MIC with activity of 100 ppm. Conclusion: This study has suggested the effect of winter cherry extract on P. aeruginosa in the in vitro assay. It s effectiveness of on in vivo system can be examined in future. https://jmb.tums.ac.ir/index.php/jmb/article/view/175 https://jmb.tums.ac.ir/index.php/jmb/article/download/175/120