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 bacte- rium 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 Ente- robacteriaceae. The purpose of this study was to determine the antimicrobial resis- tance pattern of E. coli strains isolated from patients referred to the selected hospit- als in Zahedan by tracing the blaTEM beta-lactamase gene. Over a 12 month period, 200 clinical samples were examined. Antibiotic susceptibility was deter- mined by disk diffusion test and microdilution method and the presence of bla TEM gene was evaluated by PCR. 130 isolates were potentially extended-spectrum beta- lactamase-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. Keywords: Ecsherichia coli, Disk Diffusion Test, Extended Spectrum Beta- lactamases (ESBLs