The prevalence of TEM gene among extended-spectrum beta-lactamase producing Escherichia coli in Karaj, Iran

Resistance to usually used antibiotic drug therapy represents one of the most important concerns for the treatment of bacterial infections. The increasing resistance to cephalosporin and monobactam antimicrobials is due to the production of extended-spectrum beta-lactamases (ESBLs). These ESBLs enzymes evolved via point mutations of important amino acids of extended-spectrum beta-lactamases such as TEM-1, TEM-2 and SHV-1. The aim of the present study was to investigate the prevalence of TEM gene among extended-spectrum beta- lactamase producing Escherichia coli that isolated from hospitalized patients in Karaj hospitals. In this research, a total of 77 well-characterized isolates of E. coli from patents urines were selected and identified using standard microbiological screening tests and biochemical methods. , Disks containing 10 μg of clavulanic acid and 30 μg of ceftazidime or 30 μg ceftriaxone were placed on the inoculated plates containing Mueller-Hinton agar. The cultured colonies of extended-spectrum beta lactamase producing E. coli were suspended in 100 nicrolitter ddH2O and their DNA was isolated using simple boiling method.Genotypic assay of TEM gene among extended-spectrum beta- lactamase producing Escherichia coli was performed byPCR analysis. From 77 E.coli isolate samples phenotypically examination, disk diffusion method, showed that 39.7% of cases were ESBL producing samples and 60.3% were non- ESBL. Genotype examination with degenerative primers for all 119 types of TEM gene revealed that 74 (96.1) cases were TEM positive. These results indicated the importance of TEM gene in beta-lactam antibiotics hydrolysis between E. coli strains isolated in Karaj, Iran. The identification of this gene frequency in E. coli isolates can speed up the process of diagnosis and treating of patients in clinics.

کلیدواژه ها:

Escherichia coli ، TEM ، Extended-spectrum beta- lactamase