Prevalence of Urinary Tract Infection Caused by Escherichia coli and Determining Minimum Inhibitory Concentration for Common Antibiotics in Hospitals of Zanjan, Iran

Urinary tract infection (UTI) is one of the most common bacterial infection most commonly by Escherichia coli. The aim of this study was to evaluate the resistance pattern and susceptibility of some antibiotics to E. coli isolated from urinary tract infections and to determine the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the antibiotics used, would lead to prescribing the most effective antibiotics for the treatment of patients with UTIs. In this descriptive cross-sectional study, 524 samples were collected from hospitals in Zanjan for six months from April to October 2018. After sample collection of UTIs, culture, Gram stain and differential tests were done and bacteria species were identified. Antibiotic resistance assay was performed by disk diffusion method and also MIC and MBC were determined by agar dilution method. The highest rate of resistance was to Cefotaxime (89%) and the greatest sensitivity was to Nitrofurantoin (83.2%). Also, the highest concentration of MIC and MB was related to Amoxicillin (MIC=128 μg/ml; MBC=256 μg/ml) and the low concentration related to Ciprofloxacin (MIC=0.0625 μg/ml; MBC=0.125 μg/ml). This study showed that the resistance of E. coli to most antibiotics increased and also that early detection of antibiotic resistant strain is necessary in order to select appropriate treatment and prevent the spread of antibiotic resistance.