en ميکروبيولوژي Microbiology پژوهشي Research <strong>Background:</strong> Isolation of the <em>TEM</em> beta-lactamase gene from clinical <em>Pseudomonas aeruginosa</em> and <em>Escherichia coli</em> samples provides useful information on the epidemiology of and factors involved in infections caused by these agents as well as their antibiotic resistance patterns. The aim of this study was to evaluate the antibiotic resistance of <em>P. aeruginosa</em> and <em>E. coli</em> isolated from specimens obtained in Isfahan, Iran via detection of the <em>TEM</em> gene.<br> <strong>Materials and methods:</strong> In this cross-sectional study, 120 <em>P. aeruginosa</em> and 86 <em>E. coli</em> samples isolated from urine and sputum were identified using biochemical methods. Their antimicrobial resistance pattern was investigated using the Kirby-Bauer disc diffusion method. Then, phenotypic detection of extended-spectrum beta-lactamases (ESBL) was performed using a combined disc method. Finally, the <em>TEM</em> gene in isolated samples was examined using polymerase chain reaction (PCR).&nbsp;<br> <strong>Results</strong>: <em>P. aeruginosa</em> isolates were found to show the highest resistance to tetracycline (97.5%) and amoxicillin (95%) and the highest sensitivity to aztreonam (97.5%) and amikacin (61.66%). 68 <em>P. aeruginosa</em> samples (56.6%) contained a <em>TEM</em> gene. <em>E. coli</em> isolates were found to show the highest resistance to co-trimoxazole (59.34%) and amoxicillin (55.04%), and the highest sensitivity to imipenem (69.66%) and chloramphenicol (61.92%). 62 <em>E. coli</em> samples (72.09%) contained a <em>TEM</em> gene. <div style="text-align: justify;"><strong>Conclusions:</strong>&nbsp; The alarming spread of ESBL-producing pathogens is a complicating factor in antimicrobial therapies. It is essential to employ diverse strategies for the supervision of the spread of these pathogens.</div> Antimicrobial, Escherichia coli, Pseudomonas aeruginosa, TEM, β‐lactamases 35 41 http://rmm.mazums.ac.ir/browse.php?a_code=A-10-1084-1&slc_lang=en&sid=1 Elahe Shams elahehshams80@yahoo.com 10031947532846007695 10031947532846007695 No Young Researchers and Elite Club, Falavarjan Branch, Islamic Azad University, Isfahan, Iran Behnaz Nateghi behnaz.nateqi@gmail.com 10031947532846007696 10031947532846007696 No Department of Biochemistry, Faculty of Science, Nourdanesh Institutions of Higher Education, Meimeh, Isfahan, Iran Amir Eshaghiyan amireashaghiyan@gmail.com 10031947532846007697 10031947532846007697 No Department of Genetics, Arsanjan Branch, Islamic Azad University, Arsanjan, Shiraz, Iran Parisa Behshood Parisa_behshood@yahoo.com 10031947532846007698 10031947532846007698 Yes Young Researchers and Elite Club, Falavarjan Branch, Islamic Azad University, Isfahan, Iran