Objective: In this study we aimed to determine antimicrobial susceptibility profiles and ESBL ranges of E.coli strains which were isolated by department of Clinical Microbiology Laboratory in our hospital between March 2009- March 2010.

Materials and Methods: Antimicrobial susceptibilities of E.coli strains which identified by conventional methods and automated systems in several different samples were determined with Clinical Laboratory Standards Institute (CLSI) criteria between March 2009-March 2010.

Results: 747 of isolated 2459 strains of E. coli belong to the outpatients and the rest belong to the inpatients. The highest resistance ratio was detected against to ampicillin according to inpatients 84.8% and outpatients 77.3% treatments. The lowest resistance rates were found against imipenem and amikacin. The strains that were isolated from 104 (13.9%) outpatients and 471(27.5%) hospitalized patients detected extended spectrum β-lactamase(ESBL).

Conclusion: Detection of antimicrobial resistance ranges in our hospital and selection of antimicrobial therapies according to these results will prevent ESBL production and resistance to antimicrobials.