Sahar Serajian - Department of Medical Laboratory Sciences, School of Paramedical Sciences, Zanjan University of Medical Sciences, Zanjan, Iran.
mohammad mohyeddin kazemeini - Department of Biochemistry, Payame Noor University, Branch of Tehran- Shargh, Tehran, Iran.
Siamak Heidarzadeh - Department of Microbiology and Virology, School of Medicine Sciences, Zanjan University of Medical Sciences, Zanjan, Iran.

Introduction and Objectives: Urinary tract infection (UTI) is one of the most common bacterial infections. Antibiotic resistance patterns vary in different regions. According to the increasing antibiotic resistance among strains of E. coli, aim of this study was to determine the current pattern and also to investigate changes in the antibiotic resistance patterns of E. coli in outpatients referred to the Shahid Beheshti hospital in Zanjan. Materials and Methods: In this study, 3225 urine samples were examined during a twelve months period from December 2016 to April 2017. They were all cultured and then examined for E. coli. Morphological study and identification of isolated bacteria by differential biochemical tests and using hot dyeing were performed. Antibiogram profile of the bacteria was determined by disk-diffusion test (Kirby-Bauer) according to CLSI standards. Results: The urine test result was positive in 552 (17.11 %) patients of 3225 eligible ones. The most common isolated bacteria were E. coli; 464 (84.05%). Based on the results of antimicrobial resistance test, the highest resistance was with co-trimoxazol (50.64%), nalidixic acid (47.41%), ceftriaxone (24.35%) and ciprofloxacin (20.47%). Furthermore, the lowest resistance belonged to nitrofurantoin (5.81%), amikacin (6.68%), ceftizoxim (8.40%) and gentamicin (12.28%), respectively. Conclusion: The highest sensitivity was to nitrofurantoin and the highest resistance was to Co-trimoxazol. According to the data, the treatment of UTIs should be done according to the susceptibility and resistance pattern of the area in order to prevent the occurrence of a drug resistance and treatment failure that leads to the complication of the infection.

Antibiotic resistance pattern, E. coli, Urinary tract infections.