Soltan Dallal Mm, Mobasseri G, Mehrabadi Jf, Eshraghian Mr, Rastegar Lari A, Molla Aghamirzaei H, Sabbaghi A, Azarsa A,
Volume 69, Issue 1 (4-2011)
Abstract
Background: Resistance to beta-lactam antibiotics in clinical isolates frequently results
from the production of β-lactamase enzymes. In recent years, the production of extended spectrum β-lactamases (ESBLs) and AmpC β-lactamase have greatly increased, especially in clinically isolated Escherichia coli. On the other hand, beta lactamase genes have several subfamilies and designing universal primers could be valuable in their detection. The beta-lactamase-producing E. coli which is resistant to beta-lactam antibiotics may pose a great risk to the patients. The CTX-M-1 gene is responsible for beta lactamase resistance. The purpose of this study was to find the percentage of CTX-M-1 carrying E. coli strains.
Methods: A total of 500 urine samples were collected from different hospitals in Tehran, Iran during September to February 2009. The samples were cultured on EMB agar and incubated at 37 C for 24 hours. Some biochemical tests were carried out on
the isolated samples. The presence of CTX-M-1 gene was determined by PCR on the
isolates already identified phenotypically by disk diffusion agar and combined disks. Results: In general, 200 out of the initial 500 samples were identified as E. coli, among which 128 (79.5%) were ESBLs producing strains. PCR used for the detection of CTX-M-
1 gene, showed that 99 (77.34%) out of 128 isolates contained such gene.
Conclusion: The results of this study showed a high percentage of β-lactamase resistant E. coli strains. This is a serious matter and would pose a public hazard and every step should be taken to avoid such hazard.
Soltan Dallal Mm, Azarsa M, Shirazi Mh, Rastegar Lari A, Owlia P, Fallah Mehrabadi J, Sabbaghi A, Molla Aghamirzaei H, Shamkani F, Avadis Yans S, Mobasseri G, Bakhtiari R, Sharifi Yazdi Mk,
Volume 69, Issue 5 (8-2011)
Abstract
Background: Numerous use of Beta Lactame in treatment of bacterial infections resulted in increments of drug resistance of such bacteria. One of difficulties in treatment of hospital infections is Extended Spectrum Beta Lactamase (ESBL) among isolated clinical strains of E.coli. Since some of ESBL strains shows double reaction in drug sensitivity test at in vitro and in vivo condition, therefore it makes difficulties in selection of right treatment. In the last years, CTX-M enzymes have become the most prevalent ESBLs in worldwide. The prevalence of ESBL types largely remains unknown in many parts of the Iran. This study was made to find the prevalence of ESBL-producing E.coli and molecular detection of CTX-M-1 in Tabriz.
Methods: In the present study, 400 urine samples collected between November 2009 and April 2010, from Tabriz Hospitals were studied. Out of the 400 samples, 188 E.coli isolates were detected by standard biochemical tests. Susceptibility to antimicrobial agents was tested to 10 antibiotics by the disk agar diffusion (DAD) method. ESBL production was screened by phenotypic test that included both separate and combined disk agar diffusion techniques. The screened isolates were investigated by PCR assay to detect CTX-M-1 gene.
Results: From the total 188 E.coli isolates, 82 (43.6%) were shown to produce ESBLs by phenotypic test. During the PCR method on the 82 isolates, 69 (84.1%) were confirmed as CTX-M-1 producing group.
Conclusion: The present study showed that CTX-M-producing isolates were increasing among E.coli strains and indicated the need for adequate susceptibility tests in laboratories for choosing the appropriate antibiotics for treatment.
