Clonal heterogeneity of clinical isolates of vancomycin-resistant Enterococcus faecium with unique vanS.
ABSTRACT To examine the clonal diversity of vancomycin-resistant enterococci (VRE).
A total of 900 clinical isolates of enterococci were obtained, and VRE isolates were subjected to antimicrobial susceptibility tests, biochemical fingerprinting with the PhPlate system (PhP), ribotyping and pulsed-field gel electrophoresis (PFGE) typing.
Forty-nine of all enterococcal isolates were resistant to high levels of vancomycin (MIC >or= 128) and identified as Enterococcus faecium. Biochemical fingerprinting with PhP showed that the VRE isolates were highly diverse (diversity index, D(i) = 0.93) and belonged to 24 PhP-types. The VRE could be separated into 34 and 27 types with PFGE and ribotyping, giving diversity indices of 0.98 and 0.97, respectively. The PFGE method was more discriminatory than ribotyping and PhP system for E. faecium isolates. A combination of either of the two typing methods resulted in at least 44 types. Furthermore, sequencing analysis of vanS of Tn1546 showed one nucleotide mutation (C-->A) at position 5727 in comparison with the prototype BM4147, which was found to be unique in all Iranian VRE isolates.
The isolated clinical VRE strains were highly diverse in Tehran.
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ABSTRACT: To assess the molecular characterization of disseminated vancomycin-resistant enterococci (VRE) in the intensive care units, 546 enterococci isolates were collected from different clinical samples in a prospective observational study. The results showed that a total number of 33 isolates (6 %) were resistant to vancomycin. Most of the VRE isolates 11 (34 %) were isolated from intensive care units (ICUs). 18 (55 %) VRE isolates were obtained from urinary tract infections. The results from pulsed-field gel electrophoresis showed five common types (CT) and 13 single types (ST) among the VRE isolates. The analysis showed two and one major CTs and ST among the ICUs isolates, respectively. Tn1546 transposon was analyzed using ClaI-digested long PCR (L-PCR) RFLP followed by sequencing. The results showed the presence of two different lineages of transposon among the two clonal groups. Lineage 1 with the arrangement of Tn1546 prototype in the first clonal group and the second lineage with 13 kb harboring two insertion sequences, IS1216 V and IS1542. DNA hybridization showed that vanA gene in all VRE isolates, with an exception of one isolate, was present in the same location on the genome. Overall, the results suggest that a few VRE clonal types were disseminated in ICUs in hospitals in Iran which were able to transfer their vanA with high conjugation frequency.Current Microbiology 01/2014; · 1.52 Impact Factor
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ABSTRACT: Vancomycin-resistant enterococci (VRE) represent as an immediate threat to public health. Since few active compounds are available for VRE infections, rapid identification of these isolates are essential. In the absence of any report on the genetic relatedness of Enterococcus faecalis especially Vancomycin-resistant E. faecalis (VREF) isolates in Iran, we undertook this study to characterize these isolates using random amplification of polymorphic DNA (RAPD-PCR) genotyping method. In this study, E. faecalis strains isolated from various samples collected from different wards of Children Medical Hospital (Tehran, Iran). These isolates were identified by standard laboratory procedures and tested for antimicrobial resistance to vancomycin and teicoplanin. The genetic similarity of the strains was investigated by amplification of the RAPD-PCR. In our study among 91 E. faecalis isolates, 15 (16%) were identified as VREF. The similarity pattern built for E. faecalis isolates by RAPD-PCR, demonstrated the presence of four distinct clusters (A, B, C, D). It is of interest to note that 100% of VREF isolates belonged to Clusters A, indicating that there may have occurred horizontal transmission of the same strain between patients. In conclusion, rapid spread of VREF from a clonal origin calls for implementation of careful isolation and infection control measures. Therefore, environmental control by routine disinfection of patient area as well as screening of high risk patients and isolation of colonized patients should be imposed in order to diminish risk of acquiring nosocomial VRE.Journal of preventive medicine and hygiene 06/2013; 54(2):87-9.
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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: http://www.diagnosticpathology.diagnomx.eu/vs/1270863903102282.Diagnostic Pathology 10/2013; 8(1):163. · 1.85 Impact Factor