en ميکروب شناسي Microbiology Research Article Research Article <div style="text-align: justify;"><span style="font-size:12px;"><span style="font-family:Times New Roman;"><b>Background:</b> Urinary tract infections (UTIs) caused by uropathogenic Escherichia coli (UPEC) represent a significant global health concern. Virulence factors (VFs) expressed by UPEC strains play a crucial role in promoting bacterial pathogenicity within the urinary tract. Effective treatment of these infections is frequently complicated by the high prevalence of antimicrobial resistance exhibited by Escherichia coli. The objective of this study was to investigate the VFs and antibiotic susceptibility profiles of UPEC strains isolated in the northern region of Iran.<br> <b>Methods:</b> One hundred and five urine specimens were collected from female patients diagnosed with UTIs in Rasht, located in the north of Iran. These samples underwent culturing on both Eosin Methylene Blue (EMB) agar and MacConkey agar. Following a 24-hour incubation period at 37&deg;C, pure bacterial isolates were identified through Gram staining and a battery of standard biochemical assays. The prevalence of six VF genes - <i>papC</i>, <i>sfa/foc</i>, <i>fimH</i>, <i>afa</i>, <i>ibeA</i>, and <i>neuC</i> - within UPEC strains was determined utilizing polymerase chain reaction (PCR) and subsequently confirmed via direct sequencing. Antibiotic susceptibility testing (AST) was conducted using the disk diffusion method, adhering to the guidelines established by the Clinical and Laboratory Standards Institute (CLSI M02).<br> <b>Results:</b> The study identified 65.71% of the isolates as Escherichia coli. Among the virulence genes examined, <i>fimH</i> exhibited the highest prevalence (100%), while <i>afa</i> was the least frequent (1.44%). Antibiotic resistance analysis revealed the highest rate against Cefazolin (66.66%) and the lowest against Gentamicin (24.63%). Notably, the prevalence of multi-drug resistance (MDR) was determined to be 73.91%.<br> <b>Conclusion</b>: This study underscored the significance of localized surveillance of UPEC isolates. This emphasis stems from the pathogen&#39;s considerable capacity for genetic mutation, coupled with the influence of environmental variables and individual patient characteristics. Understanding these dynamic factors at a local level is crucial for formulating the most effective strategies to combat UTIs.</span></span></div> Uropathogenic Escherichia coli, Urinary Tract Infections, Virulence factor, Drug resistance, Multiple, Antimicrobial susceptibility 42 48 http://mlj.goums.ac.ir/browse.php?a_code=A-10-1386-1&slc_lang=en&sid=1 Zahra Askari banafsheh.as72@gmail.com 100319475328460030094 0009-0000-0526-8450 No Department of Microbiology, Faculty of Basic Science, Rasht branch, Islamic Azad University, Rasht, Iran Zeynab Mirzapour mirzapooor899@gmail.com 100319475328460030095 0009-0001-6184-4413 No Department of Microbiology, Faculty of Basic Science, Rasht branch, Islamic Azad University, Rasht, Iran Tooba Shafighi tshafighi@yahoo.com 100319475328460030096 100319475328460030096 Yes Department of Microbiology, Faculty of Basic Science, Rasht branch, Islamic Azad University, Rasht, Iran Reyhaneh Ghorbanpour reyhanehghorbanpour@yahoo.com 100319475328460030097 100319475328460030097 No Department of Immunology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran