Molecular detection of TEM broad spectrum β-lactamase in clinical isolates of Escherichia coli

Abstract

Resistance to β-lactam antibiotics, along with clinical isolates, frequently results to production of β- lactamase enzymes. In recent years, the production of extended spectrum β-lactamases (ESBLs) among clinical isolates, especially Escherichia coli has greatly increased. On the other hand, β lactamase genes have several subfamilies, and designing universal primers could be valuable to detect all of them. The beta lactamase enzyme producing E. coli, resistant to β-lactam antibiotics, created many problems for the patients. The TEM gene is responsible for β-lactamase resistance. The purpose of this study was to find out the percentage of E. coli strains that carry TEM in genes. In total, 500 clinical samples were collected from different Hospitals in Tehran. All the samples were isolated on EMB and MacConkey agar and incubated at 37°C for 24 h. The identification was carried out by conventional biochemical tests. Out of the 500 samples, 200 were identified as E. coli. The TEM gene was determined by PCR method on the isolates, which were already identified as Phenotypic by disk diffusion agar and combined disk. Out of the 200 isolated E. coli strains, 128 (64%) were producing ESBls. The PCR results show that 74 isolates of E. coli (57.8%) had the TEM gene. Our findings show that the majority of the ESBL positive clinical isolates of E. coli carried the TEM gene.

Key words: Escherichia coli, β-lactamase enzymes, TEM-type extended spectrum beta-lactamases.