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.
Highlights
A major mechanism of β-lactam resistance in bacteria is the expression of the prevalence of β-lactamase enzymes (TEM)-type β-lactamases (Mammeri et al, 2001)
Our findings show that the majority of the ESBL positive clinical isolates of E. coli carried the TEM gene
We identified 89.8% of the isolates tested as ESBL producing strains according to the recommendations set forth by the Clinical and Laboratory Standards Institute (CLSI)
Summary
A major mechanism of β-lactam resistance in bacteria is the expression of TEM-type β-lactamases (Mammeri et al, 2001). According to the recommendations of the Clinical and Laboratory Standards Institute (CLSI), isolates that show reduced susceptibility to β-lactam antibiotics, especially third generation antibiotics, such as cephalosporins, are potential ESBL-expressing strains and can be confirmed in phenotypic tests using clavulanate (Clinical and Laboratory Standards Institute [CLSI], 2005). The use of such phenotypic methods is not sufficient for the unequivocal detection of strains expressing these enzymes, and additional molecular techniques are required in addition to phenotypic assays (Netzel et al, 2007). We sought to determine the prevalence of ESBLs in clinical isolates of E. coli and to detect TEM using molecular methods. As β-lactamase genes have several subfamilies, universal primers that are able to detect all β-lactamase variants would be an invaluable diagnostic tool.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
