Effects of In-Feed Copper, Chlortetracycline, and Tylosin on the Prevalence of Transferable Copper Resistance Gene,tcrB, Among Fecal Enterococci of Weaned Piglets

ABSTRACT Enterococci from pigs in Denmark, Spain, and Sweden were examined for susceptibility to antimicrobial agents and copper and the presence of selected resistance genes. The greatest levels of resistance were found among isolates from Spain and Denmark compared to those from Sweden, which corresponds to the amounts of antimicrobial agents used in food animal production in those countries. Similar genes were found to encode resistance in the different countries, but the tet(L) and tet(S) genes were more frequently found among isolates from Spain. A recently identified transferable copper resistance gene was found in all copper-resistant isolates from the different countries.

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Characterization of a unique copper resistance gene cluster in Xanthomonas campestris pv. campestris isolated in Trinidad, West Indies

European Journal of Plant Pathology ◽

10.1007/s10658-016-1035-2 ◽

2016 ◽

Vol 147 (3) ◽

pp. 671-681 ◽

Cited By ~ 7

Author(s):

Franklin Behlau ◽

Alberto M. Gochez ◽

Alshia Janel Lugo ◽

Winston Elibox ◽

Gerald V. Minsavage ◽

...

Keyword(s):

Gene Cluster ◽

Resistance Gene ◽

West Indies ◽

Xanthomonas Campestris ◽

Copper Resistance ◽

Resistance Gene Cluster ◽

Copper Resistance Gene ◽

Xanthomonas Campestris Pv Campestris

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Selection of Fecal Enterococci ExhibitingtcrB-Mediated Copper Resistance in Pigs Fed Diets Supplemented with Copper

Applied and Environmental Microbiology ◽

10.1128/aem.00364-11 ◽

2011 ◽

Vol 77 (16) ◽

pp. 5597-5603 ◽

Cited By ~ 41

Author(s):

R. G. Amachawadi ◽

N. W. Shelton ◽

X. Shi ◽

J. Vinasco ◽

S. S. Dritz ◽

...

Keyword(s):

Growth Promotion ◽

Copper Resistance ◽

Weaned Piglets ◽

S1 Nuclease ◽

Content Type ◽

Copper Supplementation ◽

The Relationship ◽

Swine Diets ◽

Ppm Level ◽

Selection Of

ABSTRACTCopper, as copper sulfate, is increasingly used as an alternative to in-feed antibiotics for growth promotion in weaned piglets. Acquired copper resistance, conferred by a plasmid-borne, transferable copper resistance (tcrB) gene, has been reported inEnterococcus faeciumandE. faecalis. A longitudinal field study was undertaken to determine the relationship between copper supplementation and the prevalence oftcrB-positive enterococci in piglets. The study was done with weaned piglets, housed in 10 pens with 6 piglets per pen, fed diets supplemented with a normal (16.5 ppm; control) or an elevated (125 ppm) level of copper. Fecal samples were randomly collected from three piglets per pen on days 0, 14, 28, and 42 and plated on M-Enterococcusagar, and three enterococcal isolates were obtained from each sample. The overall prevalence oftcrB-positive enterococci was 21.1% (38/180) in piglets fed elevated copper and 2.8% (5/180) in the control. Among the 43tcrB-positive isolates, 35 wereE. faeciumand 8 wereE. faecalis. The mean MICs of copper fortcrB-negative andtcrB-positive enterococci were 6.2 and 22.2 mM, respectively. The restriction digestion of the genomic DNA ofE. faeciumorE. faecaliswith S1 nuclease yielded a band of ∼194-kbp size to which bothtcrBand theerm(B) gene probes hybridized. A conjugation assay demonstrated cotransfer oftcrBanderm(B) genes betweenE. faeciumandE. faecalisstrains. The higher prevalence oftcrB-positive enterococci in piglets fed elevated copper compared to that in piglets fed normal copper suggests that supplementation of copper in swine diets selected for resistance.

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tcrB, a Gene Conferring Transferable Copper Resistance in Enterococcus faecium: Occurrence, Transferability, and Linkage to Macrolide and Glycopeptide Resistance

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.46.5.1410-1416.2002 ◽

2002 ◽

Vol 46 (5) ◽

pp. 1410-1416 ◽

Cited By ~ 130

Author(s):

Henrik Hasman ◽

Frank M. Aarestrup

Keyword(s):

Enterococcus Faecium ◽

Antimicrobial Agents ◽

Brain Heart Infusion ◽

Copper Resistance ◽

Conjugative Plasmid ◽

Feed Additive ◽

Strongly Correlated ◽

Glycopeptide Resistance ◽

Copper Resistance Gene ◽

Infusion Agar

ABSTRACT A newly discovered gene, designated tcrB, which is located on a conjugative plasmid conferring acquired copper resistance in Enterococcus faecium, was identified in an isolate from a pig. The tcrB gene encodes a putative protein belonging to the CPx-type ATPase family with homology (46%) to the CopB protein from Enterococcus hirae. The tcrB gene was found in E. faecium isolated from pigs (75%), broilers (34%), calves (16%), and humans (10%) but not in isolates from sheep. Resistant isolates, containing the tcrB gene, grew on brain heart infusion agar plates containing up to 28 mM CuSO4 compared to only 4 mM for the susceptible isolates. Copper resistance, and therefore the presence of the tcrB gene, was strongly correlated to macrolide and glycopeptide resistance in isolates from pigs, and the tcrB gene was shown to be located on the same conjugative plasmid as the genes responsible for resistance to these two antimicrobial agents. The frequent occurrence of this new copper resistance gene in isolates from pigs, where copper sulfate is being used in large amounts as feed additive, suggests that the use of copper has selected for resistance.

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The tcrB gene is part of the tcrYAZB operon conferring copper resistance in Enterococcus faecium and Enterococcus faecalis

Microbiology ◽

10.1099/mic.0.28109-0 ◽

2005 ◽

Vol 151 (9) ◽

pp. 3019-3025 ◽

Cited By ~ 28

Author(s):

Henrik Hasman

Keyword(s):

Binding Sites ◽

Enterococcus Faecium ◽

Copper Sulphate ◽

Copper Resistance ◽

Putative Promoter ◽

Promoter Probe ◽

Copper Resistance Gene ◽

Promoter Probe Vector ◽

Isogenic Strains ◽

Sublethal Concentrations

The plasmid-localized tcrB (transferable copper-resistance gene B) gene from Enterococcus faecium was identified to be part of an operon called the tcrYAZB operon, which has a genetic organization similar to the copYZAB copper-homeostasis gene cluster from Enterococcus hirae. Putative promoter (P tcr )- and repressor-binding sites highly similar to the E. hirae cop-promoter region were identified upstream of the tcrYAZB genes. The P tcr promoter was cloned in both the absence and the presence of the proximal repressor-encoding tcrY gene into a promoter-probe vector. Induction of the promoter was shown in liquid growth medium containing increasing concentrations of copper sulphate. To determine the growth advantage conferred by the tcrYAZB genes in a copper environment, a tcr-deletion mutant was isolated, and its growth was compared with that of its copper-resistant ancestor (strain A17sv1) in sublethal concentrations of copper sulphate. A competition assay using these two isogenic strains showed that copper sulphate concentrations of 3 mmol l−1 and above are sufficient to select for copper resistance.

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