Objective <p>This study investigates antibiotic resistance patterns, virulence factors, and phylogenetic groups of O25 and O16 serogroups in uropathogenic <i>Escherichia coli</i> (UPEC) isolates from kidney transplant recipients (KTPs) and non-KTPs. The presence of serogroups O25 and O16, resistance genes (e.g., <i>bla</i>_CTX-M, <i>bla</i>_TEM), and virulence factors (e.g., <i>fimH</i>, <i>PAI</i>) were determined using PCR. Phylogenetic groups were identified via quadruplex PCR, and genetic diversity was assessed using ERIC-PCR.</p> Results <p>A total of 111 <i>E. coli</i> isolates were examined in the present study. The O-serotyping results indicated that 18% and 3.6% of isolates were positive for O25 and O16 serogroup, respectively. In serogroup O25, the highest resistance rates were observed for nalidixic acid and cotrimoxazole, whereas in serogroup O16, the highest resistance rates were against cotrimoxazole and ampicillin-sulbactam. ESBL production was identified in 30% of O25 and 25% of O16 isolates. O25 isolates belonged to phylogenetic group B2, whereas O16 isolates were grouped in B1. ERIC-PCR revealed significant genetic diversity among isolates. The O25 serogroup is prevalent and closely associated with high antibiotic resistance and virulence, suggesting its critical role in UTI pathogenesis in transplant patients. These findings underscore the importance of monitoring resistance patterns and developing targeted therapeutic and preventive strategies for managing UPEC infections.</p>