STUDY OF ENTEROCOCCAL SUSCEPTIBILITY PATTERNS ISOLATED FROM CLINICAL SPECIMENS IN TABRIZ, IRAN

Abstract

Objectives: To identify the prevalence of enteroccoci species in clinical specimens, to determine their susceptibilities to some antibiotics for treatment, and to detect the vanA-specific 377-bp fragment from the genomic DNA of all vancomycin resistant enteroccoci (VRE). Methodology: One hundred thirty seven isolates of enterococci species were obtained from samples of patients who were referred to microbiology laboratory of two hospitals in Tabriz from March 2001 to April 2002. After identification of enterococcal species by biochemical methods, the antibiotic susceptibility of isolates was determined by standard disk diffusion test according to NCCLS. MIC tests for vancomycin were also carried out for VRE strains by macro-dilution method. The vanA-specific 377-bp fragment was amplified from the genomic DNA of all VRE by PCR. Results: The isolates were found to consist of E. faecalis (90.5%), E. faecium (5.84%) and Enterococcus species (3.66%). According to susceptibility data obtained, six (4.38%) out of 137 isolates were found to be VRE with MIC e"32ig/ml. The vanA gene fragments of Enterococcus faecalis, Enterococcus faecium, Enterococcus gallinarum and Enterococcus durans, were amplified from isolates and were detected. Conclusion: Finding of this study shows an emergence of VRE along with increased rate of resistant enterococci in Tabriz.