Characterization of the Mechanisms of Fluoroquinolone Resistance in Vancomycin-Resistant Enterococci of Different Origins

Background Vancomycin-resistant enterococci (VRE) represent several types of transferable vancomycin resistance gene clusters. The vanD type, associated with moderate to high level vancomycin resistance, has only sporadically been described in clinical isolates. The aim of this study was to perform a genetic characterization of the first VanD-type VRE strains detected in Norway. Methods The VanD-type VRE-strains (n = 6) from two patient cases were examined by antimicrobial susceptibility testing and whole genome sequencing (WGS) to uncover Van-phenotype, strain phylogeny, the vanD gene clusters, and their genetic surroundings. The putative transferability of vanD was examined by circularization PCR and filter mating. Results The VanD-type Enterococcus faecium (n = 4) and Enterococcus casseliflavus (n = 2) strains recovered from two cases (A and B), expressed moderate to high level vancomycin resistance (MIC 64—>256 mg/L) and various levels of teicoplanin susceptibility (MIC 2—>256 mg/L). WGS analyses revealed phylogenetically different E. faecium strains (A1, A2, and A3 of case A and B1 from case B) as well as vanD gene clusters located on different novel genomic islands (GIs). The E. casseliflavus strains (B2 and B3 of case B) were not clonally related, but harbored nearly identical novel GIs. The vanD cluster of case B strains represents a novel vanD-subtype. All the vanD-GIs were integrated at the same chromosomal site and contained genes consistent with a Clostridiales origin. Circular forms of the vanD-GIs were detected in all strains except B1. Transfer of vanD to an E. faecium recipient was unsuccessful. Conclusions We describe the first VanD-type E. casseliflavus strains, a novel vanD-subtype, and three novel vanD-GIs with a genetic content consistent with a Clostridiales order origin. Despite temporal occurrence, case A and B E. faecium strains were phylogenetically diverse and harbored different vanD subtypes and vanD-GIs.

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Characterization of fecal vancomycin-resistant enterococci with acquired and intrinsic resistance mechanisms in wild animals, Spain

Microbial Ecology ◽

10.1007/s00248-015-0648-x ◽

2015 ◽

Vol 72 (4) ◽

pp. 813-820 ◽

Cited By ~ 13

Author(s):

Carmen Lozano ◽

David Gonzalez-Barrio ◽

Maria Cruz Camacho ◽

Jose Francisco Lima-Barbero ◽

Javier de la Puente ◽

...

Keyword(s):

Resistance Mechanisms ◽

Wild Animals ◽

Intrinsic Resistance ◽

Vancomycin Resistant Enterococci ◽

Vancomycin Resistant

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Molecular characterization of vancomycin-resistant enterococci and extended-spectrum β-lactamase-containingEscherichia coliisolates in wild birds from the Azores Archipelago

Avian Pathology ◽

10.1080/03079457.2011.599061 ◽

2011 ◽

Vol 40 (5) ◽

pp. 473-479 ◽

Cited By ~ 24

Author(s):

Nuno Silva ◽

Gilberto Igrejas ◽

Pedro Rodrigues ◽

Tiago Rodrigues ◽

Alexandre Gonçalves ◽

...

Keyword(s):

Molecular Characterization ◽

Wild Birds ◽

Azores Archipelago ◽

Vancomycin Resistant Enterococci ◽

Extended Spectrum ◽

Vancomycin Resistant

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A Clonal Lineage of VanA-Type Enterococcus faecalis Predominates in Vancomycin-Resistant Enterococci Isolated in New Zealand

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.47.1.204-210.2003 ◽

2003 ◽

Vol 47 (1) ◽

pp. 204-210 ◽

Cited By ~ 41

Author(s):

Janet M. Manson ◽

Stefanie Keis ◽

John M. B. Smith ◽

Gregory M. Cook

Keyword(s):

New Zealand ◽

Enterococcus Faecalis ◽

Pfge Pattern ◽

Pulsed Field Gel Electrophoresis ◽

Feed Additive ◽

Clonal Lineage ◽

M Gene ◽

Vancomycin Resistant Enterococci ◽

Vancomycin Resistant

ABSTRACT Avoparcin was used as a feed additive in New Zealand broiler production from 1977 until June 2000. We report here on the effects of the usage and discontinuation of avoparcin on the prevalence of vancomycin-resistant enterococci (VRE) in broilers. Eighty-two VRE isolates were recovered from poultry fecal samples between 2000 and mid-2001. VRE isolates were only obtained from broiler farms that were using, or had previously used, avoparcin as a dietary supplement. Of these VRE isolates, 73 (89%) were VanA-type Enterococcus faecalis and nine (11%) were VanA-type Enterococcus faecium. All E. faecalis isolates were found to have an identical or closely related pulsed-field gel electrophoresis (PFGE) pattern of SmaI-digested DNA and were susceptible to both ampicillin and gentamicin. The PFGE patterns of the nine E. faecium isolates were heterogeneous. All VRE contained both the vanA and ermB genes, which, regardless of species or PFGE pattern, resided on the same plasmid. Eighty-seven percent of the VRE isolates also harbored the tet(M) gene, while for 63 and 100%, respectively, of these isolates, the avilamycin and bacitracin MICs were high (≥256 μg/ml). Five of eight vancomycin-resistant E. faecalis isolates recovered from humans in New Zealand revealed a PFGE pattern identical or closely related to that of the E. faecalis poultry VRE isolates. Molecular characterization of Tn1546-like elements from the VRE showed that identical transposons were present in isolates from poultry and humans. Based on the findings presented here, a clonal lineage of VanA-type E. faecalis dominates in VRE isolated from poultry and humans in New Zealand.

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