Evaluation of Antibiotic Susceptibility of Escherichia coli and Klebsiella spp. Isolated from Urinary Tract Infections of Patients Attending a University Hospital in Tehran

E. coli and Klebsiella spp. are recognized as most prevalent bacteria causing urinary tract infection (UTI), the most common bacterial infection. Decreasing of antimicrobial susceptibility in urinary pathogens has made difficulty in treatment of UTI. The aim of this study was to determine antibiotic susceptibility of E. coli and Klebsiella spp. isolated from urine of patients with UTI attending a university hospital in Tehran (Iran) to guide the choice of empiric antibiotic treatment. All midstream urine samples obtained from patients with UTI from 23 October 2012 to 20 June 2013 at Shahid Mostafa Khomeini hospital in Tehran were cultured and bacterial isolates were identified by standard methods. Susceptibility pattern of E. coli and Klebsiella spp. isolates were determined by the disk diffusion method in accordance with CLSI guideline against ampicillin, amikacin, co-amoxiclav, cephalothin, cefotaxime, ciprofloxacin, co-trimoxazole, gentamicin, tetracycline, nalidixic acid and nitrofurantoin. During 8 month study period, altogether 331 urine had produced positive culture, which most common isolates were E. coli (n=216) and Klebsiella spp. (n=50). E. coli showed maximum susceptibility to amikacin (97%) and nitrofurantoin (92.5%), while Klebsiella spp. isolates had shown maximum susceptibility to amikacin (95.8%) and gentamicin (83.8%). Susceptibility to ampicillin and co-amoxiclav were very low. Decreased susceptibility to most common antibiotics in urine prevalent isolates in this study should be considered in treatment of UTI.