Evaluation of presence of the bla-SHV and bla-AmpC (CITM, FOX) β-lactamase genes in clinical isolates of Escherichia coli

Resistance to beta-lactam antibiotics along withclinical isolates is frequently resulting production of β-lactamaseenzymes. In recent years, the production of extended spectrum β- lactamases (ESBLs) and AmpC β-lactamase among clinical isolateespecially Escherichia coli is greatly increased. On the other hand,beta lactamase genes have several subfamilies, and designing universal primers could be valuable to detect all of them. Therefore, the aim of this study was to survey prevalence of phenotypic ESBLsand detection of SHV and AmpC (CITM, FOX)-type β-lactamase genes by using universal primers through PCR. A total of 500 clinical samples were collected from hospitals of Tehran and 200 E.coli isolates were detected by standard biochemical tests. Subsequently, these isolates were screened for β-lactamase production by Disk diffusion method andcombined disk. Resistant isolates were evaluated for molecular assessing of SHV, CITM and FOX genes by using PCR. Among entire of 200 E.coli, 128(64%) isolates wereselected via phenotypic tests for detection of bla-SHV and bla- AmpC (CITM, FOX) genes via PCR. With 95% confidence, 7(5.5%) and 13(10.2%) E.coli harbor bla-SHV and bla-CITM,respectively. Fox gene was not detected in any samples. Results were showed that complete detection of β-lactamase enzymes is essential for resistant control and the appropriate prescription of β-lactam drugs. So using molecular assay with phenotypic test is important.