Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 8 3 2016 10 04 175 180 EN Mansour Rezaei School of Health, Kermanshah University of Medical Sciences, Kermanshah, Iran Alisha Akya Nosocomial Infection Research Centre, School of Medicine, Kermanshah University of Medical Sciences,Kermanshah, Iran Azam Elahi 3Department of Microbiology, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran Keyghobad Ghadiri Department of Microbiology, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran Somayeh Jafari Emam Reza hospital, Kermanshah University of Medical Sciences, Kermanshah, Iran 2015 10 23 2016 06 06 Background and Objectives: Citrobacter freundii is an opportunistic pathogen causing nosocomial infections and resistant to various antibiotics. We aimed to determine the clonal relationship of C. freundii isolates using Pulsed-Field Gel Electrophoresis (PFGE). Materials and Methods: Fifty clinical isolates of C. freundii were collected from the main hospital in Kermanshah. After antibiotic susceptibility testing and screening for extended-spectrum beta lactamase (ESBL), all isolates were genotyped by PFGE. The DNA fragment patterns were analysed using Gelcompar II version 6.6 software. The Dice coefficient was used to calculate similarities for cluster analysis. Results: The PFGE results of 12 (24%) and 38 (76%) ESBL positive and negative isolates, respectively, produced 39 clusters (X1-39) with different genotype patterns. The X1 and X2 clusters were the major clusters, each contained 3 isolates from different hospital wards. However, the majority of isolates showed a high genotypic diversity. Conclusion: Results revealed the genotypic diversity of C. freundii isolates indicating the various sources for the bacterial isolates. However, the presence of isolates with similar genotypes indicates the common origin for these strains and may reflect the strain dissemination within the hospital wards, in particular in infectious ward and intensive care unit. https://ijm.tums.ac.ir/index.php/ijm/article/view/742 https://ijm.tums.ac.ir/index.php/ijm/article/download/742/590