Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 12 5 2020 10 31 388 394 Somayeh Bakhtiari Brucellosis Research Center, Hamadan University of Medical Sciences, Hamadan, Iran Hassan Mahmoudi Department of Microbiology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran Sara Khosravi Seftjani Department of Microbiology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran Mohammad Ali Amirzargar Urology and Nephrology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran Sima Ghiasvand Department of Microbiology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran Mohammad Ebrahim Ghaffari Department of Biostatistics and Epidemiology, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran Maryam Adabi Brucellosis Research Center, Hamadan University of Medical Sciences, Hamadan, Iran 2020 04 14 2020 07 13 Background and Objectives: Escherichia coli is the most common causative agent of urinary tract infections (UTIs) in 90-80% of patients in all age groups. Phylogenetic groups of these bacteria are variable and the most known groups are A, B1, B2 and D. The present study aimed to evaluate the phylogenetic groups of E. coli samples obtained from UTIs and their relation with antibiotic resistance patterns of isolates. Materials and Methods: In this study 113 E. coli isolates were isolated from distinct patients with UTIs referred to Hamadan hospitals. After biochemical and molecular identification of the isolates, typing and phylogenetic grouping of E. coli strains were performed using multiplex PCR targeting chu, yjaA and TSPE4.C2 genes. The anti-microbial susceptibility of the isolates to amikacin, ampicillin, trimethoprim-sulfamethoxazole, amoxicillin/clavulanic acid, ciprofloxacin, cefotaxime, imipenem, aztreonam, gentamicin, meropenem, nitrofurantoin, nalidixic acid and cefazolin was determined using disk diffusion method. Results: Of 113 isolates, 50 (44.2%), 35 (31%), 23 (20.4%) and 5 (4.4%) of samples belonged to group B2, group D, group A and group B1 phylogenetic groups respectively. All isolates were susceptible to meropenem, imipenem (100%), followed by amikacin (99.1%). The highest resistance rates were observed against ampicillin (74.3%) and nalidixic acid (70.8%). Correlation between phylogenetic groups and antibiotic susceptibilities was significant only with co-amoxiclav (P = 0.006), which had the highest resistance in phylogenetic group A. Conclusion: Prevalence of different phylogroup and resistance associated with them in E. coli samples could be variable in each region. Therefore, investigating of these items in E. coli infections, could be more helpful in selecting the appropriate antibiotic treatment and epidemiological studies. https://ijm.tums.ac.ir/index.php/ijm/article/view/2585 https://ijm.tums.ac.ir/index.php/ijm/article/download/2585/1270