Vancomycin-resistant enterococci among clinical isolates from north-west Iran: Identification of therapeutic surrogates

Tabriz University of Medical Sciences, Iran.
Journal of Medical Microbiology (Impact Factor: 2.25). 12/2011; 61(Pt 4):600-2. DOI: 10.1099/jmm.0.036780-0
Source: PubMed


Global emergence and dissemination of vancomycin resistance among enterococci is a serious concern especially in developing countries, requiring progressive research efforts. Present investigation was carried out on clinical isolates of enterococci obtained from three tertiary hospitals located in northwest of Iran. Multiplex PCR was performed on 220 enterococcal isolates for the presence of vanA, vanB, genus - species specific targets. Subsequently, alternative therapeutic options were evaluated for vancomycin resistant enterococci (VRE) strains. From isolated enterococci, 152 (69.1%) and 68 (30.9%) were E. faecalis and E. faecium, respectively. Of 48 VRE strains detected genotypically, vanA genotype was the predominant and three strains were found to possess vanB genes. One hundred and thirty three isolates (60.45%) revealed high level resistance to gentamicin. Amongst alternative agents, resistance towards quinipristin/dalfopristin was distinctly revealed by VRE isolates while, all were found sensitive to linezolid and except one strain to daptomycin, rendering latter antibiotics better therapeutic options. Clinicians and microbiologists should thus, be aware of the increasing prevalence of VRE and alternative agents should be evaluated against them.

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Available from: Yaeghob Sharifi, Feb 08, 2014
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    • "The prevalence of E. faecium has been increased in Iranian hospitals during the last few years. In the present study, the ratio of infections due to E. faecalis to those caused by E. faecium was 1.2: 1 (51.3% versus 41.4%) which is still higher than some previous reports published from Iran and some other countries [4,15,16]. The increased ratio was supported by enhancement of VREfm strains. "
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    ABSTRACT: Enterococcus faecium is a multi-resistant nosocomial pathogen causing infection in debilitated patients. Vancomycin-resistant enterococcus faecium (VREfm) are a major concern and increased dramatically worldwide especially in hospitals environment. The current study focused on determining the high prevalence and distribution patterns of antibiotic resistance and also its genetic linkages among various VREfm strains isolated from indoor hospitalized patients in four major Iranian teaching hospitals of Tehran. The clinical samples were obtained from hospitalized patients during September 2010 to June 2011 from different teaching hospitals of Tehran. Antibiotics Resistance patterns, minimum inhibition concentration (MIC) value for vancomycin, ampicillin, gentamicin and presence of genetic linkage among the isolates were determined by pulsed-field gel electrophoresis (PFGE). Overall, total of 92 (41.4%) isolates were identified as E. faecium, 45 (49%) were resistant to vancomycin with an MIC50 of [greater than or equal to] 128 mg/L. The results showed that simultaneous resistance to teicoplanin, ampicillin, gentamicin, ciprofloxacine, tetracycline and erythromycin were observed the most frequent pattern. All the vancomycin resistant E. faecium isolates carried the vanA gene. intensive care units (ICUs) and Kidney transplantation, are most probably the wards with highest risk of infection by VRE. 17 pulsotypes were also detected by PFGE, most of the related pulsotypes belongs to the same hospitals. This study shows the high alarming prevalence of Enterococcus faecium infection and similar clones of VREfm strains in Iranian hospitals with threatening resistance phenotypes. Virtual slides: The virtual slides for this article can be found here:
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    ABSTRACT: Enterococcis are a part of the normal flora of the human gastrointestinal tract, and play an important role in the spread of resistance genes and produce antibiotic-resistant strains. With increasing the use of vancomycin antibiotics, Vancomycin-resistant enterococci (VRE) are one of the major nosocomial pathogens in worldwide. The aim of this study was to investigate the frequency of phenotype and genotype of van genes in vancomycine resistant Enterococci. Methods: In this cross-sectional descriptive study, after isolating and identifying 165 strains of enterococci from clinical specimens in different wards of Alzahra hospital, the enterococcus isolates were identified by biochemical confirmation tests. Resistance of each isolate to vancomycin determined by disk diffusion and E-Test method and was tested for the presence of the Van A and Van B genes by Real time PCR. Results: The results of the 165 isolates of enterococci collected from clinical specimens showed 79 (48%) enterococcus was resistant by disk diffusion method to vancomycin, but using E-test, only 40 (25%) enterococci was resistant in high level to vancomycin. Real-time-PCR assay of 40 samples showed 37 patients (92/5%) included Van A gene and 3 (7/5%) with Van B gene. Conclusion: Based on the results of the present study, the rate of isolation of Van A-containing strains was higher than that of Van B-containing of Alzahra Hospital in Isfahan. Real Time-PCR has a high specificity compared to other phenotypic methods E-Test and disk diffusion method.
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