E. coli is the most common urinary tract pathogen (12). Moreover, most cases of E. coli infection in this study were related to the urinary system, accounting for more than half of the cases. Also, studies carried out in Iran and other neighboring and non-neighboring countries have confirmed this result (13, 14). In addition, women were the most infected individuals with E. coli (70.1%), which is consistent with other studies conducted in Tehran, Isfahan and Rasht (10, 15, 16). On the other hand, the bacterial isolates in the present study showed the lowest antibiotic resistance rates against amikacin in both hospitals. An Iranian study performed in 2019 showed that 2.2% of the clinical isolates of E. coli were resistant to this antibiotic (17). However, other studies conducted in Iran (18), Saudi Arabia (12) and Turkey (19), detected no amikacin resistant isolates of E. coli. These results indicate the good efficacy of amikacin as one of the effective antibiotics against infections caused by E. coli. Also, the results of this study showed low antibiotic resistance, except against ampicillin and cefalexin, in E. coli isolated from Bu-Ali Sina hospital compared to burn hospital. Due to the weakened immune system of burn patients, broad-spectrum antibiotics are used to treat bacterial infections in this group, which may increase the prevalence of antibiotic resistance (20). With the exception of carbapenems, the above results are consistent with other Iranian studies conducted in 2019 (21, 22). The antibiotic resistance rate of E. coli strains in Turkey was also much lower than in the present study (20). However, their research conducted on 21 urine samples, which may be the reason for lower resistance rate. Differences in antibiotic resistance rates in different regions of the world can be due to genetic differences in resistant strains, various antibiotic use policies in regional hospitals, levels of arbitrary use of antibiotics in the community and various study time (23). Among the antibiotics studied in this study, ampicillin was the least effective ones with the highest resistance rate, which was similar to the results obtained in other Iranian studies carried out in Ahvaz, Rasht and Kashan (15, 22, 24). These results indicate that unlike amikacin, ampicillin is not suitable for the treatment of E. coli infections in Iran. Moreover, resistance to carbapenems among isolates collected from Bu-Ali Sina hospital in this study was similar to other studies in Iran and neighboring countries (13, 19, 21, 22, 25), while the reported carbapenem resistance rates in non-neighboring countries such as Malaysia and Nigeria were 29.2% and 19.7%, respectively (26, 27). This discrepancies may be due to the differences in the type of sample, as Bu-Ali Sina hospital is a specialized pediatric hospital. However, resistance to carbapenems was observed extensively in the Zare as a burn hospital in the present study, which is justifiable given that the hospital is a specialized burn center. Beside, quinolones and fluoroquinolones such as nalidixic acid and ciprofloxacin are also used to treat UTIs. Similar studies, in Ahvaz (22) and Sanandaj (21), reported 64.2% and 78.8% ciprofloxacin resistance, respectively, which is consistent with the results of the burn hospital in the present study. In other studies (19, 27), the rate of quinolone resistance was higher than that of fluoroquinolones, which was consistent with the results of this study. This may be due to the greater use of drugs such as nalidixic acid to treat UTIs. Numerous factors, including supplementary use of antibiotics in agriculture and veterinary medicine, also contribute to the development of antibiotic resistance (28). Moreover, one of the serious problems worldwide is the multi-drug resistance and the development of MDR strains, which is a major concern in the treatment of infections caused by E. coli (8, 29). In this study, 80.9% of the urinary isolates of E. coli were MDR, which was very similar to the study performed in Ahwaz (22). In the research of Badamachi et al, (18), 54.6% of urinary isolates were MDR, while only 1 to 5-year-old children were studied. Since the prevalence of MDR E. coli strains, especially in burn patients, can increase morbidity and mortality rates (29), so their presence can be a major risk factor for the patients. Understanding the resistance rates of the clinical isolates of E. coli to common antibiotics in hospitals is essential to control the antibiotic resistance of this bacterium. According to the results of the present study and other studies, aminoglycosides are almost effective drugs against E. coli infections, which can be suggested as the selective antibiotics in the treatment of resistant strains in this area. On the other hand, caring for the elderly and the high risk patients for the infection with E. coli, such as burn and ICU patients, is of great importance, which can lead to reduced infection-related mortality and reduced rates of disease transmission.