Tehran University of Medical Sciences Journal of Medical Bacteriology 2251-8649 3 1-2 2015 10 13 22 27 EN Mohammad Dadook Faculty of Biological Sciences, Islamic Azad University, Tehran North Branch, Tehran, IR Iran. Sedigheh Mehrabian Faculty of Biological Sciences, Islamic Azad University, Tehran North Branch, Tehran, IR Iran. Saeed Irian Department of Cell and Molecular Biology, Faculty of Biological Sciences, Kharazmi University, Tehran, IR Iran. 2015 10 12 2015 10 12 Background: Due to the importance of the metal zinc as an essential biological element with known toxic properties, and considering the widespread secondary infections caused by Pseudomonas aeruginosa strains with resistance to antibiotics and disinfectants, the present study aimed at exploring the antimicrobial properties of the metal zinc in both clinical and environmental multiple drug resistant (MDR) strains of P. aeruginosa. MDR in P. aeruginosa is defined as the resistance to several antibiotics. Methods: Bacterial strains were cultured in cetrimide agar medium at 37 °C for 48 h. Strains were identified both morphologically and biochemically. MIC values of the metal zinc were reported using the broth microdilution method. Results: A total of 84 strains were isolated and identified. MIC values for sensitive and MDR strains were reported at 20 and 130 ppm, respectively. Conclusions: It was concluded that the metal zinc at concentrations greater than 130 ppmwill have an antimicrobial effect on all sensitive and MDR strains of P. aeruginosa. https://jmb.tums.ac.ir/index.php/jmb/article/view/14 https://jmb.tums.ac.ir/index.php/jmb/article/download/14/11