Assessment of Third Generation Cephalosporin (Ceftazidime and Ceftriaxone) Resistant Escherichia Coli Strains Isolated from Zahedan Hospitals by Tracing the TEM Gene

Escherichia coli is a Gram-negative, facultative anaerobic, rod-shaped bacterium and member of the Enterobacteriaceae family. E. coli is common in various infections, including hospital-acquired urinary tract infections. Ceftriaxone and ceftazidime are most commonly-used antibiotics to treat infections caused by Enterobacteriaceae. The purpose of this study was to determine the antimicrobial resistance pattern of E. coli strains isolated from patients referred to the selected hospitals in Zahedan by tracing the blaTEM beta-lactamase gene. Over a 12 month period, 200 clinical samples were examined. Antibiotic susceptibility was determined by disk diffusion test and microdilution method and the presence of bla TEM gene was evaluated by PCR. 130 isolates were potentially extended-spectrum betalactamase- producing and 72 isolates contained the TEM gene. The results of the present study indicate a high rate of antibiotic resistance among E. coli isolates to ceftriaxone and ceftazidime. Therefore, it is recommended to perform antibiogram tests before prescribing antibiotic therapy.