Frequency of E. coli Clinical Isolates Producing Blashv and Blatem Extended- Spectrum Beta-Lactamases


Fatemeh Gashgi 1 , Habib Zeighami 2 , * , Fakhri Haghi 2

1 MSc of Microbiology, Science and Research Branch, Islamic Azad University, Arak, Iran.

2 Assistant Professor Department of Microbiology, Zanjan University of Medical Sciences, Zanjan, Iran.

How to Cite: Gashgi F, Zeighami H, Haghi F . Frequency of E. coli Clinical Isolates Producing Blashv and Blatem Extended- Spectrum Beta-Lactamases, Hormozgan Med J. 2015 ; 19(4):e87554.


Hormozgan Medical Journal: 19 (4); e87554
Published Online: November 29, 2014
Article Type: Research Article
Received: August 21, 2013
Accepted: November 29, 2014


Introduction: Production of extended-spectrum beta-lactamase enzymes (ESBLs) in E. coli
creates many problems for patients. These enzymes are located on transferable elements and
can hydrolyze penicillins, broad-spectrum cephalosporins, and aztreonam. This study aimed to
determine the clinical isolates of E. coli producing ESBLs of blaSHV and blaTEM in the city of
Methods: This cross-sectional study was performed on 200 E. coli isolates from clinical
samples, including urine, feces, and secretions. The samples were cultured on EMB agar
medium and the isolates were confirmed with various diagnostic tests. Then the sensitivity
of strains to antibiotics and the production of ESBLs were determined by disc diffusion and
combined disc methods, respectively. Finally, the presence of blaSHV and blaTEM genes was
investigated by PCR using specific primers.
Results: Amoxicillin had the highest resistance by 68.5% (137 isolates) and imipenem the
lowest by zero percent. Resistance to the studied antibiotics were as follows; co-trimoxazole
46.5% (93 isolates), cefotaxime 34.5% (69 isolates), ceftazidime 31.5% (63 isolates),
cefepime 29.5% (59 isolates), gentamycin 28.5% (57 isolates), aztreonam 45% (90 isolates),
ciprofloxacin 25.5% (51 isolates), co-amoxiclave 18.5% (37 isolates), cefoxitin 19% (38
isolates), and amikacin 4.5% (9 isolates). According to the combined disc test, 66 strains
(33%) were ESBL-producing enzymes and the frequency of blaTEM and blaSHV genes was
46.9% (31 isolates) and 56% (37 isolates), respectively.
Conclusion: Given the resistance of ESBL strains to existing antibiotics and the ability to
transfer these genes to other clinical isolates, performing antibiotic sensitivity tests and
detection of ESBLs in laboratories is necessary for reducing treatment failure.



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