Shahcheraghi F, Noveiri H, Nasiri S. Detection of bla TEM and bla SHVgenes among clinical isolates of E. coli from Tehran hospitals . Iran J Med Microbiol 2007; 1 (3) :1-8
URL:
http://ijmm.ir/article-1-88-en.html
1- Department of Microbiology, Pasteur Institute of Iran, Tehran , feresh100@yahoo.com
2- Islamic Azad University, Lahijan Branch, Lahijan
3- Department of Microbiology, Pasteur Institute of Iran, Tehran
Abstract: (16754 Views)
Background and Objectives: The pathogenic strains of Escherichia coli cause severe septicemia, urinary
tract infection and wound sepsis. Resistance of this organism to the expanded-spectrum cephalosporins
occurs via the production of extended-spectrum β-lactamases (ESBLs) such as TEM and SHV. These
enzymes hydrolyze oxyimino cephalosporins (cefotaxime, ceftazidime) and monobactams (aztreonam). This
study was conducted to determine the drug susceptibility and prevalence of ESBL phenotypes of E. coli
isolates at Tehran hospitals.
Material and Methods: collectively, 200 isolates of E. coli were obtained from 5 hospitals in Tehran. The
antibiotic susceptibility patterns of all clinical specimens were determined using disk diffusion method.
Phenotypic confirmatory test was used to detect ESBL producing isolates. The MICs of ceftazidime and
imipenem were determined using Microbroth dilution assay. Isolates with MIC≥2µg/ml were screened by
PCR to detect blaTEM and blaSHV genes.
Results: Resistance to ceftazidime and cefotaxime were 30.1% and 32.1% respectively. All isolates were
susceptible to imipenem. 52.5% of them (n=105) were positive in phenotypic confirmatory test. Resistance
to ciprofloxacin among ESBL positive strains was 41%. The blaTEM and blaSHV genes were found among
24% (n=48) and 6% (n=12) of isolates respectively. Six isolates (3%) contained both genes.
Conclusion:At Tehran hospitals, the rate of resistance to ceftazidime and prevalence of ESBL phenotype
among the isolates of E. coli are high. It is necessary to seek a remedy for monitoring the ESBLs in these
health settings. TEM is the dominant enzyme among the ESBL producing strains of E. coli in Iran.
Type of Study:
Original Research Article |
Subject:
Medical Bacteriology Received: 2013/11/12 | Accepted: 2013/11/14 | ePublished: 2013/11/14