Antibacterial susceptibility of Escherichia coli among outpatients with community-acquired urinary tract infection in Hamadan, Iran

Escherichia coli is the main cause of community-acquired urinary tract infections (UTIs). The aims of the present study were to examine the susceptibility profile of E. coli causing UTIs and to identify factors associated with antimicrobial resistance. A cross-sectional study was conducted in Hamadan City, Iran, between 2012 and 2013. Patients referred to Farshchian or Shahid Beheshti Hospitals and diagnosed with UTI caused by E. coli were enrolled in the study. Susceptibility testing to commonly used antimicrobial agents was performed by the disk diffusion method. Relevant data were abstracted, and analysis was performed to identify factors associated with antimicrobial resistance. A total of 154 patients were enrolled in the study. Among the respective number of E. coli isolates, the highest susceptibility was observed to nitrofurantoin (94.1%) and gentamicin (86.4%) and the lowest to amoxicillin/clavulanic acid (35.1%), trimethoprim/sulfamethoxazole (38.3%) and ciprofloxacin (51.9%). Twenty-four isolates (15.6%) were susceptible to all antimicrobial tested, 31 (20.1%) were resistant to one agent and 99 (64.3%) exhibited resistance to at least two different classes of antibiotics [multidrug-resistant (MDR) phenotype]. Patients with prior use of antibiotics during the past 3 months and those who had an episode of UTI in the past 2 years were at higher risk of being infected with MDR E. coli (P = 0.034 and P = 0.001, respectively). In conclusion, a substantial proportion of E. coli causing UTI exhibited a MDR phenotype. History of UTI and prior use of antibiotics were associated with increased risk of infection caused by MDR E. coli.