title: Detection of extended-spectrum β-lactamase (ESBL) and plasmid-borne blaCTX-Mand blaTEMgenes among clinical strains of Escherichia coli isolated from patients in the north of Iran.
abstract: Escherichia coli is an important cause of hospital-acquired infections worldwide. Antimicrobial resistance leads to treatment failure of hospital infections caused by E. coli. Production of extended-spectrum β-lactamases (ESBLs) is one of the major causes of antibiotic resistance in these bacteria. This study aimed to investigate the frequency of blaTEMand blaCTX-Mgenes in ESBL-producing E. coli strains isolated from clinical specimens of patients admitted to six hospitals in the north of Iran. A total of 160 E. coli strains were isolated from various clinical samples of hospitalised patients. Antibiotic resistance patterns were determined by the Kirby-Bauer disk diffusion method. The double-disk phenotypic confirmatory test was carried out amongst β-lactam-resistant isolates to detect ESBL-producing strains. Plasmid DNA of ESBL-producing strains was extracted and subjected to PCR for detection of the blaTEMand blaCTX-Mgenes, and isolates were extensively verified by sequencing. The highest resistance rate was to amoxicillin; all E. coli isolates (100%) were susceptible to imipenem. Amongst the 160 clinical E. coli isolates, 83 (51.9%) were ESBL-positive, of which 27 (32.5%) and 72 (86.7%) were positive for blaTEMand blaCTX-M, respectively. This study is the first report of an ESBL phenotype disseminated in hospitals in the north of Iran. These findings showed that there was a direct relationship between the development of resistance to β-lactam antibiotics and production of TEM and CTX-M enzymes.
authors.affiliation: Department of Microbiology, Islamic Azad University, Lahijan Branch, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Haghighatpanah
authors.affiliation: Department of Microbiology, Research Center for Molecular Medicine, Hamadan University of Medical Sciences, Hamadan, Iran.
authors.forename: Amir Sasan
authors.initials: AS
authors.lastname: Mozaffari Nejad
authors.affiliation: Department of Microbiology, Faculty of Medicine, Guilan University of Medical Sciences, Rasht, Iran. Electronic address: alimojtahedi@yahoo.com.
authors.forename: Ali
authors.initials: A
authors.lastname: Mojtahedi
authors.affiliation: Department of Microbiology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Nour
authors.initials: N
authors.lastname: Amirmozafari
authors.affiliation: Department of Microbiology, Faculty of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran.
authors.forename: Habib
authors.initials: H
authors.lastname: Zeighami
mesh_terms: D003430:Cross-Sectional Studies; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology; D006801:Humans; D007492:Iran / Q000453:epidemiology; D010957:Plasmids / Q000235:genetics*; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D001618:beta-Lactamases
keywords: CTX-M gene; ESBL; Escherichia coli; PCR; TEM gene