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

2002 ◽  
Vol 46 (5) ◽  
pp. 1410-1416 ◽  
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.

scholarly journals Relationship between Copper, Glycopeptide, and Macrolide Resistance among Enterococcus faecium Strains Isolated from Pigs in Denmark between 1997 and 2003

2005 ◽  
Vol 49 (1) ◽  
pp. 454-456 ◽  
Author(s):  
Henrik Hasman ◽  
Frank M. Aarestrup
Keyword(s):  
Copper Sulfate ◽  
Significant Relationship ◽  
Enterococcus Faecium ◽  
Macrolide Resistance ◽  
Copper Resistance ◽  
Glycopeptide Resistance ◽  
Continued Use

ABSTRACT A significant relationship between copper resistance (tcrB), glycopeptide resistance (Tn1546), and macrolide resistance [erm(B)] in Enterococcus faecium isolated from pigs was found. The tcrB gene was located closely upstream of the Tn1546 element. However, the continued use of copper sulfate has not been able to maintain high levels of macrolide and glycopeptide resistance.

scholarly journals Antimicrobial Resistance among Enterococci from Pigs in Three European Countries

2002 ◽  
Vol 68 (8) ◽  
pp. 4127-4129 ◽  
Author(s):  
Frank Møller Aarestrup ◽  
Henrik Hasman ◽  
Lars Bogø Jensen ◽  
Miguel Moreno ◽  
Inmaculada A. Herrero ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Antimicrobial Agents ◽  
Animal Production ◽  
Copper Resistance ◽  
European Countries ◽  
Food Animal ◽  
Copper Resistance Gene ◽  
S Genes

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.

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

Microbiology ◽  
2005 ◽  
Vol 151 (9) ◽  
pp. 3019-3025 ◽  
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.

scholarly journals Microbiological Evaluation of Elastomeric Chains

2007 ◽  
Vol 77 (5) ◽  
pp. 890-893 ◽  
Author(s):  
Giovana Rembowski Casaccia ◽  
Janaína C. Gomes ◽  
Daniela Sales Alviano ◽  
Antonio Carlos de Oliveira Ruellas ◽  
Eduardo Franzotti Sant' Anna
Keyword(s):  
Antimicrobial Agents ◽  
Brain Heart Infusion ◽  
Inhibitory Effect ◽  
Pathogenic Microorganisms ◽  
Inhibition Zones ◽  
The Moment ◽  
Careful Manipulation ◽  
Elastomeric Chains ◽  
Infusion Agar

Abstract Objectives: To evaluate in vitro the surface of elastomeric chains of different manufacturers to verify the presence of pathogenic microorganisms at the moment of unpacking and analyze a possible inhibitory effect of the elastomeric chain when exposed to microorganisms of the oral cavity, for example, Streptococcus mutans, Lactobacillus casei, and Candida albicans. Materials and Methods: Elastomeric chains from Ortho-Organizers Inc, 3M Unitek, and Dental Morelli were placed in petri plates with brain heart infusion agar medium and in sterile test tubes with brain heart infusion broth. The samples were incubated at 37°C and analyzed at 24 hours, 48 hours, 3 days, and 7 days. In addition, elastomeric chains from the three manufacturers were placed in dishes, inoculated with microorganisms, incubated at 37°C, and analyzed after 24 and 72 hours. Results: No microorganism growth was detected after all incubation periods. No inhibition zones were identified surrounding the elastomeric chain. Conclusions: The results suggest that the fabrication of elastomeric chain is in accordance with biohazard concepts. However, careful manipulation is necessary to avoid colonization of pathogenic microorganisms since the composition of the elastomeric chains analyzed do not include antimicrobial agents.

Occurrence oftcrB, a Transferable Copper Resistance Gene, in Fecal Enterococci of Swine

2010 ◽  
Vol 7 (9) ◽  
pp. 1089-1097 ◽  
Author(s):  
Raghavendra G. Amachawadi ◽  
Nick W. Shelton ◽  
Megan E. Jacob ◽  
Xiaorong Shi ◽  
Sanjeev K. Narayanan ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Copper Resistance ◽  
Copper Resistance Gene

Characterization of Enterococcus faecium mutants resistant to mundticin KS, a class IIa bacteriocin

Microbiology ◽  
2003 ◽  
Vol 149 (10) ◽  
pp. 2901-2908 ◽  
Author(s):  
Youko Sakayori ◽  
Mizuho Muramatsu ◽  
Satoshi Hanada ◽  
Yoichi Kamagata ◽  
Shinichi Kawamoto ◽  
...  
Keyword(s):  
Enterococcus Faecium ◽  
Antimicrobial Agents ◽  
Wild Type Strain ◽  
Unsaturated Fatty Acids ◽  
Class I ◽  
Wild Type ◽  
Food Preservatives ◽  
In The Wild ◽  
Resistant Mutants

The emergence and spread of mutants resistant to bacteriocins would threaten the safety of using bacteriocins as food preservatives. To determine the physiological characteristics of resistant mutants, mutants of Enterococcus faecium resistant to mundticin KS, a class IIa bacteriocin, were isolated. Two types of mutant were found that had different sensitivities to other antimicrobial agents such as nisin (class I) and kanamycin. Both mutants were resistant to mundticin KS even in the absence of Mg2+ ions. The composition of unsaturated fatty acids in the resistant mutants was significantly increased in the presence of mundticin KS. The composition of the phospholipids in the two resistant mutants also differed from those in the wild-type strain. The putative zwitterionic amino-containing phospholipid in both mutants significantly increased, whereas amounts of phosphatidylglycerol and cardiolipin decreased. These changes in membrane structure may influence resistance of enterococci to class IIa and class I bacteriocins.

Efficacy of Nisin-Coated Polymer Films To Inactivate Salmonella Typhimurium on Fresh Broiler Skin†

2000 ◽  
Vol 63 (9) ◽  
pp. 1189-1196 ◽  
Author(s):  
NANDINI NATRAJAN ◽  
BRIAN W. SHELDON
Keyword(s):  
Salmonella Typhimurium ◽  
Shelf Life ◽  
Brain Heart Infusion ◽  
Tween 80 ◽  
Linear Low Density Polyethylene ◽  
Packaging Films ◽  
Gram Positive Bacteria ◽  
Subsequent Storage ◽  
Infusion Agar ◽  
Treatment Application

Nisin is an antimicrobial peptide produced by the food-grade microorganism Lactococcus lactis subsp. lactis. This peptide inhibits many gram-positive bacteria, and when combined with chelating agents it inhibits gram-negative bacteria such as Salmonella sp. The efficacy of packaging films treated with nisin-containing formulations to reduce Salmonella contamination of fresh broiler drumstick skin and increase the refrigerated shelf life was investigated. Three films (5.1 cm2) of varying hydrophobicities (polyvinyl chloride [PVC], linear low density polyethylene, nylon) were coated with one of three liquid formulations (pH 3.5 to 3.8) composed of 100 μg/ml nisin and varying concentrations of citric acid, EDTA, and Tween 80. The treated films were applied either wet or dry to 5.1-cm2 broiler drumstick skin samples inoculated with a nalidixic acid-resistant (NAr) strain of Salmonella Typhimurium. After incubation at 4°C for 24 h the populations of surviving Salmonella TyphimuriumNAr organisms were recovered from the skin and film samples using a rinse procedure and enumerated on brain heart infusion agar containing 800 ppm NA. Log reductions (untreated versus treated skin) in Salmonella TyphimuriumNAr populations ranged from 0.4 to 2.1. Treatment formulation compositions and wet versus dry treatment application also influenced the extent of kill. The shelf life of refrigerated broiler drumsticks was extended by 0.6 to 2.2 days following a 3-min immersion in a nisin-containing treatment solution and subsequent storage in a foam tray pack containing a nisin-treated PVC overwrap and a nisin-treated absorbent tray pad. These findings demonstrated that Salmonella Typhimurium and spoilage microorganism populations on the surface of fresh broiler skin and drumsticks can be significantly reduced using immersion treatments, absorbent tray pads, and packaging films treated with nisin-containing formulations.

scholarly journals Effects of the Movement of Insertion Sequences on the Structure of VanA Glycopeptide Resistance Elements in Enterococcus faecium

2000 ◽  
Vol 44 (5) ◽  
pp. 1362-1364 ◽  
Author(s):  
Ana L. C. Darini ◽  
Marie-France I. Palepou ◽  
Neil Woodford
Keyword(s):  
Structural Change ◽  
Inverted Repeat ◽  
Enterococcus Faecium ◽  
Insertion Sequence ◽  
Host Strain ◽  
Insertion Sequences ◽  
Glycopeptide Resistance ◽  
Related Element

ABSTRACT A Tn1546-related element with IS1216V at position 8839 underwent a structural change after storage of the host strain of Enterococcus faecium at 4°C. The element acquired IS1542 at position 3932, nucleotides 8732 to 8831 were deleted, and the first 3417 nucleotides were lost and replaced by an inverted copy of the IS1216V–vanY–vanZ-inverted-repeat block from the 3′ end. Insertion sequence movement is likely to play a key role in the evolution of VanA resistance elements.

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