21 Journal NI, 2014, 1(2), 21-30 Antibiotic susceptibility patterns and ESBL of Escherichia coli isolated from hospitalized patients in Kermanshah, western Iran Zhaleh Dezfoolimanesh 1 , Nasrollah Sohrabi 1, 2* , Mohammad Rasoul Tohidnia 3 1- Department of Medical Laboratory Sciences, School of Paramedicine, Kermanshah University of Medical Sciences, Kermanshah, Iran. 2- Nosocomial Infection Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran. 3- Department of Radiology , School of Paramedicine, Kermanshah University of Medical Sciences, Kermanshah, Iran. *Corresponding author: Nasrollah Sohrabi Email: na.sohrabi@yahoo.com Article Type: Original Article Receive: Nov 2014 Revised: Jan 2015 Accept: Mar 2015 ABSTRACT Background and Objective: Production of extended-spectrum ß- lactamases (ESBLs) is the major cause of resistance to β-lactam antibiotics in Escherichia coli. In this study, the antibiotic susceptibility pattern and the prevalence of ESBL-producing E. coli isolates were studied in a hospital in Kermanshah, western Iran. Methods: E. coli isolates were identified using microbiological and biochemical standard tests. Antibiotic susceptibility testing and the detection of ESBL-producing E. coli isolates were done according to Clinical and Laboratory Standards Institute (CLSI) criteria. Results: The most frequent isolation source of E. coli clinical isolates was urine (94.1%). Most of the isolates were resistant against ampicillin (88.2%). Imipenem and amikacin were the most active antibiotics having 81.2% and 78.8% activity, respectively. Results of antimicrobial susceptibility showed that 57.6% of isolates were multidrug resistant (MDR). Results of Combined Disk Test (CDT) showed that 56.5% of isolates were ESBL positive, and among MDR isolates, 79.6% were ESBL producers. There was a significant difference in ESBL MDR patterns between ESBL producers and non-producer ESBL E.coli isolates (p<0.05). Conclusion: Results of this study showed that most isolates were MDR and pose problems for therapeutics. Prevention and control of antibiotics resistance requires efforts at increasing surveillance and infection control and limitation of unnecessary antibiotic use. Keywords: Antibiotic resistance, ESBL, Escherichia coli. Journal of Nosocomial Infection Original Article