Genetic characterization of vanG, a novel vancomycin resistance locus of Enterococcus faecalis.
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Enterococcus faecalis strain WCH9 displays a moderate level of resistance to vancomycin (MIC = 16 microgram/ml) and full susceptibility to teicoplanin but is negative by PCR analysis using primers specific for all known enterococcal vancomycin resistance genotypes (vanA, vanB, vanC, vanD, and vanE). We have isolated and sequenced a novel putative vancomycin resistance locus (designated vanG), which contains seven open reading frames, from this strain. These are organized differently from those of all the other enterococcal van loci, and, furthermore, the individual vanG gene products exhibit less than 50% amino acid sequence identity to other van gene products. (+info)
Nitrofurantoin is active against vancomycin-resistant enterococci.
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The activity of nitrofurantoin was tested against 300 isolates of Enterococcus faecium, Enterococcus faecalis, and Enterococcus gallinarum. No isolates tested were resistant to nitrofurantoin (MIC, >/=128 microg/ml), including vancomycin-resistant E. faecium isolates with vanA- and vanB-positive genotypes and vancomycin-resistant E. gallinarum isolates. We conclude that nitrofurantoin may provide effective treatment of urinary tract infections caused by vancomycin-resistant enterococci. (+info)
Linezolid therapy of vancomycin-resistant Enterococcus faecium experimental endocarditis.
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We compared the activities of linezolid (25 mg/kg of body weight, administered intraperitoneally every 8 h) and of vancomycin (25 mg/kg of body weight, administered intraperitoneally every 8 h) in a rat model of vanA vancomycin-resistant Enterococcus faecium experimental endocarditis. Results were expressed as median log(10) CFU per gram of vegetation after 3 days of treatment. The median log(10) CFU per gram of vegetation was 10.1 among 7 untreated control animals, 10.2 among 9 vancomycin-treated animals, and 7.9 among 10 linezolid-treated animals. Linezolid treatment was more active (P < 0.05) than vancomycin treatment or no treatment. (+info)
Restoration of vancomycin susceptibility in Enterococcus faecalis by antiresistance determinant gene transfer.
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We assessed the ability of gene transfer to reverse vancomycin resistance in class A (VanA) glycopeptide-resistant Enterococcus faecalis. Recombinant shuttle vectors containing a vanH promoter-vanA antisense gene cassette fully restored vancomycin susceptibility through a combined transcriptional activator binding domain decoy and inducible vanA antisense RNA effect. (+info)
Molecular analysis of Tn1546-like elements in vancomycin-resistant enterococci isolated from patients in Europe shows geographic transposon type clustering.
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Resistance mechanism relatedness was studied in 18 clinical, European vanA vancomycin-resistant enterococci. Molecular analysis revealed 10 Tn1546-like elements, suggesting two evolutionary lineages. Lineage I dominated the European mainland, and lineage II dominated the United Kingdom and Israel. Geographic clustering reflected different types of meat consumption between countries, since each lineage is associated with colonization of different animals. (+info)
Diversity of Tn1546 elements in clinical isolates of glycopeptide-resistant enterococci from Scottish hospitals.
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The Tn1546-related elements of 48 Van glycopetide-resistant enterococci were compared. Ten distinct Tn1546 types were identified with variation primarily due to IS1542 and IS1216V-like insertions. Clonal isolates frequently differed in their Tn1546 type, indicating instability of Tn1546-related elements. A putative hybrid promoter was identified, generated upstream of vanR by the insertion of IS1542. The presence of this hybrid promoter was associated with constitutive expression of the van genes and elevated teicoplanin resistance. (+info)
Probiotic Enterococcus faecium strain is a possible recipient of the vanA gene cluster.
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The characteristics of Enterococcus faecium have led to concern regarding the safety of probiotics that contain this bacterium. The results of an in vitro filter mating assay indicate that a probiotic E. faecium strain might be a potential recipient of vancomycin resistance genes. (+info)
Detection and typing of vancomycin-resistance genes of enterococci from clinical and nosocomial surveillance specimens by multiplex PCR.
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Ninety-three clinical isolates of vancomycin-resistant enterococci (VRE) collected from nine hospitals in Taiwan were examined for the presence of vanA, vanB, vanC1, or vanC2/vanC3 genes by a multiplex PCR. Forty-seven of these VRE isolates were vanA positive, 1 contained both vanC1 and vanA, 40 harboured vanB, 2 were vanC1, and 3 were identified to be vanC2/vanC3. Twenty-four vanA isolates were sensitive to teicoplanin and thus did not have a typical VanA phenotype. Five isolates with the VanC phenotype harboured vanB. None of the 40 clinically isolated vancomycin-susceptible E. faecium or E. faecalis and the vancomycin-resistant Leuconostoc and Pediococcus isolates were positive for any of the van genes. While performing nosocomial surveillance, VRE were isolated from 47 of 467 rectal swabs by culture. Compared with the conventional culture method, the sensitivity and specificity of the multiplex PCR for detecting and identifying vancomycin-resistance genes in enterococci directly from culture-positive broth were 97.9% and 100%, respectively. The results suggest that genotypic characterization of vancomycin-resistance is necessary for all clinical VRE isolates and that the multiplex PCR assay can be an alternative method for this purpose. (+info)