Increase in prevalence of vancomycin resistant isolates of Enterococcous faecium at Labbafinejad hospital

Background: Vancomycin resistant isolates of Enterococcous faecium (VRE) have previously been reported from Tehran Hospitals. However, little data were available on the genetic heterogeneity of VRE isolates among the Iranian population. Therefore the emergence of infections with the new clones of VRE needs to be investigated. The drug resistance surveillance program at Labbafinejad hospital has to be continued. Patients and methods: Overall, 103 non-replicative isolates of enterococci grown from urine samples in the first quarter of 2005 were screened for their susceptibilities to different antibiotics. Ribotyping was then used to genetically characterize the isolates of VRE. Results: Using disk diffusion method, all isolates were found susceptible to linezolid. Resistance to high level concentration of gentamicin was detected in 65.7% of isolates. All isolates of E. faecalis (n=86) were susceptible to vancomycin. Conversely, over 70% of E. faecium isolates (n=12) showed resistance to this glycopeptide. The VRE isolates recovered from patients in 2005 were heterogeneous comparing with those of 2000. Conclusion: Conventional bacteriology confirmed the increase in the rate of VRE. It appears that a variety of new VRE clones have arisen recently at different wards of this hospital as determined by ribotyping.