كليدواژه :
vanB , پلاسميد , فاضلاب , تهران , انتروكك , vanA
چكيده لاتين :
Background and objective: Enterococci are important not only because they are a leading cause of nosocomial infections, but also because they may have a significant role in dissemination and persistence of antimicrobial resistance. The aim of the study was to detect and analyze the antibiotic and genetic diversity of the Enterococcal strains in Tehran sewage and comparison between biochemical and genetic methods for identification of enterococcus spp.
Materials and methods: 712 isolates of Enterococci were selected on mEnterococcus agar medium and identified at the species level by the common biochemical tests and specific genus and species primers. Antibiotic susceptibility test of isolates and the MIC was also done using Etest. Analysis of the plasmid profiles and the PCR tests for vanA and vanB genes were also done.
Results: The biochemical tests showed that 402, 170, 82, 25, 16, 11, 3, 2 and 1 isolates were E. faecium, E. hirae, E. faecalis, E. gallinarum, E. casseliflavus, E. mundtii, E. raffmosus, E. dispar and E. avium respectively.
The antibiotic resistance of the isolates were as follow: 4, 4, 18, 20, 30 and 6% of the isolates were resistant to vancomycin, gentamicin, tetracycline, ciprofloxacin, erythromycin and chloramphenicol respectively. MIC test showed that 19 of the isolates were highly resistant to vancomycin (MIC>512 jig/ml). The plasmid profiles of the isolates showed foure different profiles. 100% and 32% of Vancomycin Resistant Enterococcus isolates had vanA and vanB gene respectively. Isolates tested by PCR agreed with results obtained using standard biochemical tests.
Conclusion: Enterococcal species is considered to have a high distribution in Tehran sewage. The presence of VRE was limited to E. faecium. PCR for genus and species determination of enterococci provide an improved, rapid and specific method for identification of this group of bacteria in contrast to Biochemical tests
