[Evaluation of presence of the bla-SHV and bla-AmpC [CITM, FOX] beta-lactamase genes in clinical isolates of Escherichia coli]

ABSTRACT

Resistance to beta-lactam antibiotics along with clinical isolates is frequently resulting production of beta-lactamase enzymes. In recent years, the production of extended spectrum beta-lactamases [ESBLs] and AmpC beta-lactamase among clinical isolate especially 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 ESBLs and detection of SHV and AmpC [CITM, FOX]-type beta-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 beta-lactamase production by Disk diffusion method and combined 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 were selected 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 beta-lactamase enzymes is essential for resistant control and the appropriate prescription of beta-lactam drugs. So using molecular assay with phenotypic test is important