Background
Evolving resistant uropathogens are associated with elevated risk of morbidity and mortality both in nosocomial and in spinal cord injury (SCI)-associated urinary tract infections (UTIs). Clinico-epidemiological studies are therefore essential to facilitate empirical therapy and decrease treatment time.
Material and Method
This study was performed at Al-Zahra Hospital, Isfahan University of Medical Sciences, Isfahan, Iran. All E. coli-infected UTI hospitalized patients, except those with symptoms of UTI prior to admission or in the first 48 hours of hospitalization, were included in this study as group A. All E. coli-infected SCI-associated UTIs were included in group B. Urine samples were cultured and the MICs of nine antibiotics on the isolated bacteria were determined by the gradient concentration method with E. coli ATCC25922 as the standard control.
Results
Antibiotic-resistant uropathogens were more prevalent among the nosocomial than the SCI-associated UTIs. The antibiotic-resistance rates of isolated E. coli in the nosocomial and SCI-associated UTIs were 13.9% and 5.9% for amikacin, 65% and 40.5% for ceftazidime, 69.8% and 32.4% for ceftriaxone, 50% and 41.2% for ciprofloxacin, 56.9% and 13.6% for gentamicine, 2.1% and 0% for imipenem, 3.9% and 0% for meropenem, and 73.6% and 63.6% for trimethoprim/sulfamethoxazole, respectively. Only resistance to nalidixic acid was mildly higher in SCI E. coli. The MIC50 of all the antibiotics except nalidixic acid was higher in nosocomial E. coli.
Conclusions
Despite more risk factors for antibiotic-resistant E. coli in SCI patients, antibiotic-resistant E. coli was observed more in nosocomial UTIs, which may be attributable to the hospital environment.

Keywords: Urinary Tract Infections - microbiology, Spinal Cord Injuries - microbiology, Escherichia coli Infections - microbiology, Escherichia coli - isolation & purification, Disease Susceptibility, Cross Infection - microbiology