Phenotypic and Molecular Characterization of Extended-Spectrum beta-Lactamase Produced by Escherichia coli, and Klebsiella pneumoniae Isolates in an Educational Hospital

Gholipour, A. and Soleimani, N. and Shokri, D. and Mobasherizadeh, S. and Kardi, M. and Baradaran, A. (2014) Phenotypic and Molecular Characterization of Extended-Spectrum beta-Lactamase Produced by Escherichia coli, and Klebsiella pneumoniae Isolates in an Educational Hospital. JUNDISHAPUR JOURNAL OF MICROBIOLOGY, 7 (10).

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Abstract

Background: Extended-spectrum beta-lactamases (ESBLs) are a group of enzymes that hydrolyze antibiotics, including those containing new cephalosporins, and they are found in a significant percentage of Escherichia coli and Klebsiella pneumoniae strains. With the widespread use of antibiotics, difficulties with infection therapy caused by drug resistant organisms, especially those that have acquired resistance to beta-lactams, such as broad-spectrum cephalosporins, have amplified the above-mentioned organisms. Objectives: This study was conducted to characterize ESBLs among E. coli and K. pneumonia isolates by molecular and phenotypic methods. Materials and Methods: Different strains of E. coli and K. pneumonia were collected from patients with urinary tract infections. The ESBL phenotype was determined by a double disk diffusion test (DDDT). In addition, polymerase chain reaction (PCR) analysis specific for beta-lactamase genes of the TEM and SHV family was carried out. The PCR products were run on agarose and examined for DNA bands. Results: A total of 245 E. coli and 55 K. pneumonia strains were isolated from different samples. In total, 128 of the 300 isolates were confirmed as potential ESBLs producers as follows: 107 (43.67%) E. coli and 21 (38.18%) K. pneumonia. ESBLs genes were found in 24 isolates (18.75%): 21 E. coli and 3 K. pneumonia isolates. The TEM gene was present in 13 (12.14%) E. coli strains, but it was not detected in K. pneumonia. In addition, the SHV gene was present in 8 (7.47%) E. coli and 3 (14.28%) K. pneumonia isolates. Five (4.67%) of the E. coli isolates harbored both TEM and SHV genes. All isolates (100%) were susceptible to imipenem. The lowest rates of resistance to other antibiotics were observed for; piperacillin-tazobactam (6.25%), amikacin (12.5%) and gentamicin (14.84%). The rates of resistance to other antibiotics were as follow: nitrofurantoin (16.4%), nalidixic acid (23.43), co-trimoxazole (25%), cefepime (32%), ciprofloxacin (55.46%), ampicillin (69.53%), ceftazidime (100%), and cefotaxime (100%). Conclusions: The results of this study indicate the widespread prevalence of ESBLs and multiple antibiotic resistance in E. coli and K. pneumoniae. Therefore, beta-lactam antibiotics and beta-lactamase inhibitors or carbapenems should be prescribed based on an antibacterial susceptibility test.

Item Type: Article
Uncontrolled Keywords: Phenotypic; Molecular; extended-spectrum beta-lactamase (ESBL); Escherichia coli; Klebsiella pneumoniae
Subjects: WC Communicable Diseases
QU Biochemistry > Cell biology and genetics
Divisions: Faculty of Medicine > Basic Sciences Academic Groups > Department of Immunology
Faculty of Medicine > Basic Sciences Academic Groups > Department of Microbiology
Depositing User: zahra bagheri .
Date Deposited: 30 Jul 2017 06:07
Last Modified: 30 Jul 2017 06:07
URI: http://eprints.skums.ac.ir/id/eprint/2049

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