Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 8 5 2016 12 19 298 306 EN Shadi Shahsavan Antimicrobial Resistance Research Center, Rasul-e-Akram Hospital, Iran University of Medical sciences, Tehran, Iran Maliheh Nobakht Antimicrobial Resistance Research Center, Rasul-e-Akram Hospital, Iran University of Medical Sciences,Tehran, Iran AND Department of Anatomy, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran Abdolaziz Rastegar-Lari Department of Microbiology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran Parviz Owlia Molecular Microbiology Research Center, Shahed University, Tehran, Iran Bita Bakhshi Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran 2016 01 16 2016 10 28 Background and Objectives: Strains of Shigella spp. can cause shigellosis, or bacillary dysentery.that is a public health problem worldwide. The aim of this study was to describe the population structure and genetic relatedness of multidrug resistant S. sonnei and S. flexneri isolated during a one year period from children with diarrhea in Tehran, Iran. Materials and Methods: A total of 70 Shigella spp. were detected during the study period . Twenty MDR isolates of Shigella spp. were randomly selected and used in this study. Bacterial identification was performed by conventional biochemical and serological and confirmed by molecular method. After antimicrobial susceptibility testing, we used Multilocus sequence typing (MLST) for subtyping isolates. Results: We found 14 Shigella sonnei and 6 Shigella flexneri isolates. Results of MLST showed five sequence types (ST) (145, 152, 241, 245, 1502) and BURST analysis revealed the largest number of single locus variant (SLV) and highest frequency (FREQ) for ST152. ST 152 with nine members was predicted as the founder by BURST. Frequency for ST 1502 and ST 245 was four isolates and the least frequency was seen for ST 241 and 145 with one and two members, respectively. ST 145 and ST 245 were described as singletons in BURST. All isolates with ST145 and ST245 were identified as Shigella flexneri. Conclusion: Annual Multi locus sequence typing of MDR Shigella would help us in better understanding of dominant species and comparing our results with the same studies in other countries especially our neighbor countries in source tracking purposes.   https://ijm.tums.ac.ir/index.php/ijm/article/view/888 https://ijm.tums.ac.ir/index.php/ijm/article/download/888/665