Abstract

Enterococcus faecalis has emerged as an important nosocomial pathogen worldwide, infections and outbreaks of Vancomycin-resistant enterococci (VRE) still appear to be rare in Baghdad. In the present study, 20 isolates of E. faecalis were collected from 252 clinical samples (151 urine and 101 blood) from different hospitals in Baghdad and 3 isolates from 50 stool samples from healthy people during the period 1/10/2010 to 1/12/2010. All isolates were identified through morphological, cultural and biochemical tests using Rapid ID-32 strep. Vancomycin-resistance phenotype was determined by the agar diffusion method; results showed that five clinical isolates (25%) and two faecal isolates (66.7%)were resistant to vancomycin. Minimum inhibitory concentrations (MIC) of clinical VRE isolates ranged between 4 to 512 µg/ml and the MICs for isolates of faecal origin were 64 and 128 µg/ml. Seven vancomycin-resistant E. faecalis isolates were examined for their drug resistance and plasmid DNAs. Of the 5 clinical isolates, 2 isolates exhibited resistance to azlocillin (Azl) and ofloxacillin (Ofx). All clinical and stool isolates were resistant to oxacillin (Ox), cefepime (Fep), rifampicin (Ra) and tetracycline (Te). Imipenem and ampicillin were found to be the most effective agents against the isolates. The detection of plasmid DNA by gel electrophoresis showed that some E. faecalis isolates carried a high molecular weight plasmid that was transferred to the recipient by filter mating. The putative presence of vanA gene was examined by PCR, using specific primers. Positive PCR amplifications were obtained in all 7 isolates for vanA gene.Vancomycin resistant E. faecalis increased gradually in Baghdad hospitals and high dissemination of vanA gene, which encoded high resistance level to vancomycin. Continued surveillance is required to prevent further spread of these serious resistances.

Key words: Bacteria, vancomycin, Enterococcus faecalis