From vanA Enterococcus hirae tovanA Enterococcus faecium: a Study of Feed Supplementation with Avoparcin and Tylosin in Young Chickens

ABSTRACT Fifteen newborn chickens were isolated in separate cages after 1 month of living together, divided into three groups, and challenged for 5 weeks with seed food which either was supplemented with avoparcin (10 mg/kg of animal food) or tylosin (40 mg/kg) or was nonsupplemented. At 9 weeks of age and after the 5-week challenge, all chickens received nonsupplemented feed for 4 additional weeks. At 4, 9, and 13 weeks of life, feces were collected and inoculated on M-Enterococcusagar plates with and without vancomycin (4 μg/ml).vanA-containing Enterococcus hirae was isolated from 11 of 15 chickens before antibiotic challenge, without detection of vancomycin-resistant Enterococcus faecium. At 9 weeks of age and after the 5-week avoparcin challenge, vanA E. hiraestrains were no longer detected, but five of five chickens now hadvanA E. faecium. At a lower frequency, vanA E. faecium had also displaced vanA E. hirae in both the tylosin group (one of four chickens) and the control group (two of five chickens). One month after avoparcin discontinuation, the number of chickens colonized with vanA E. faecium decreased from five to one. All vanA-containing E. hirae strains detected in the first month of life and most of thevanA-containing E. faecium strains detected in the second month of life showed identical ApaI andSmaI restriction patterns, respectively, when analyzed by pulsed-field gel electrophoresis. All vanA E. hiraeisolates transferred glycopeptide and macrolide resistance toEnterococcus faecalis JH2-2 in vitro; the level of glycopeptide resistance was higher in the transconjugants than in the donor E. hirae strains. These data suggest that E. hirae may be a significant source of vanAdeterminants with the potential of transfer to other enterococcal species from humans or animals.

Download Full-text

Copper Resistance in Enterococcus faecium, Mediated by the tcrB Gene, Is Selected by Supplementation of Pig Feed with Copper Sulfate

Applied and Environmental Microbiology ◽

10.1128/aem.02979-05 ◽

2006 ◽

Vol 72 (9) ◽

pp. 5784-5789 ◽

Cited By ~ 74

Author(s):

Henrik Hasman ◽

Isabelle Kempf ◽

Bï¿½rangï¿½re Chidaine ◽

Roland Cariolet ◽

Annette Kjï¿½r Ersbï¿½ll ◽

...

Keyword(s):

Enterococcus Faecium ◽

Copper Resistance ◽

Control Group ◽

Animal Group ◽

Young Pigs ◽

Enterococcal Species ◽

High Level ◽

First Time ◽

Selection Of

ABSTRACT The tcr gene cluster mediates in vitro copper resistance in Enterococcus faecium. Here we describe the selection of tcr-mediated copper resistance in E. faecium in an animal feeding experiment with young pigs fed 175 mg copper/kg feed (ppm), which is the concentration commonly used for piglets in European pig production. tcr-mediated copper resistance was not selected for in a control group fed low levels of copper (6 ppm). We also show coselection of macrolide- and glycopeptide-resistant E. faecium in the animal group fed the high level of copper. Finally, we identify the tcr genes in the enterococcal species E. mundtii, E. casseliflavus, and E. gallinarum for the first time.

Download Full-text

PCR Fragment Length Polymorphism Analysis of Vancomycin-Resistant Enterococcus faecium

Journal of Clinical Microbiology ◽

10.1128/jcm.38.8.2885-2888.2000 ◽

2000 ◽

Vol 38 (8) ◽

pp. 2885-2888 ◽

Cited By ~ 15

Author(s):

Susan Donabedian ◽

Ellie Hershberger ◽

Lee Ann Thal ◽

J. W. Chow ◽

Don B. Clewell ◽

...

Keyword(s):

Length Polymorphism ◽

Fragment Length ◽

Enterococcus Faecium ◽

Fragment Length Polymorphism ◽

Pulsed Field Gel Electrophoresis ◽

Polymorphism Analysis ◽

Vancomycin Resistant Enterococcus ◽

Glycopeptide Resistance ◽

Pcr Product ◽

Vancomycin Resistant

In this study, the glycopeptide resistance element, Tn1546, in 124 VanA Enterococcus faeciumclinical isolates from 13 Michigan hospitals was evaluated using PCR fragment length polymorphism. There were 26 pulsed-field gel electrophoresis (PFGE) types, which consisted of epidemiologically related and unrelated isolates from separate patients (1992 to 1996). Previously published oligonucleotides specific for regions in thevanA gene cluster of Tn1546 were used to amplify vanRS, vanSH, vanHAX,vanXY, and vanYZ. The glycopeptide resistance element, Tn1546, of E. faecium 228 was used as the basis of comparison for all the isolates in this study. Five PCR fragment length patterns were found, as follows. (i) PCR amplicons were the same size as those of EF228 for all genes in the vanAcluster in 19.4% of isolates. (ii) The PCR amplicon forvanSH was larger than that of EF228 (3.7 versus 2.3 kb) due to an insertion between the vanS and vanH genes (79.2% of isolates). (iii) One isolate in a unique PFGE group had avanSH amplicon larger than that of EF228 (5.7 versus 2.3 kb) due to an insertion in the vanS gene and an insertion between the vanS and vanH genes. (iv) One isolate did not produce a vanSH amplicon, but whenvanS and vanH were amplified separately, both amplicons were the same size as those as EF228. (v) One isolate had avanYZ PCR product larger than that of EF228 (2.8 versus 1.6 kb). This study shows that in a majority of the VanA E. faecium isolates, Tn1546 is altered compared to that of EF228. A total of 79.2% of the study isolates had the same-size insertion between the vanS and vanH genes. The results of this study show dissemination of an altered Tn1546 in heterologous VanA E. faecium in Michigan hospitals.

Download Full-text

Comparison of Genomic Methods for Differentiating Strains of Enterococcus faecium: Assessment Using Clinical Epidemiologic Data

Journal of Clinical Microbiology ◽

10.1128/jcm.36.11.3327-3331.1998 ◽

1998 ◽

Vol 36 (11) ◽

pp. 3327-3331 ◽

Cited By ~ 12

Author(s):

Connie Savor ◽

Michael A. Pfaller ◽

Julie A. Kruszynski ◽

Richard J. Hollis ◽

Gary A. Noskin ◽

...

Keyword(s):

Enterococcus Faecium ◽

Gel Electrophoresis ◽

Genomic Dna ◽

Restriction Endonuclease Analysis ◽

Pulsed Field Gel Electrophoresis ◽

Agarose Gel Electrophoresis ◽

Subspecies Level ◽

Vancomycin Resistant ◽

Ideal Method ◽

Endonuclease Analysis

Genomic DNA extracted from 45 vancomycin-resistantEnterococcus faecium (VRE) isolates was cleaved withHindIII and HaeIII and subjected to agarose gel electrophoresis. The ability of this method (restriction endonuclease analysis [REA]) to distinguish strains at the subspecies level was compared with results previously determined by pulsed-field gel electrophoresis (PFGE). Chart reviews were performed to provide a clinical correlation of possible epidemiologic relatedness. A likely clinical association was found for 29 patients as part of two outbreaks. REA found 21 of 21 isolates were the same type in the first outbreak, with PFGE calling 19 strains the same type. In the second outbreak with eight patient isolates, HindIII found six were the same type and two were unique types. HaeIII found three strains were the same type, two strains were a separate type, and three more strains were unique types, while PFGE found three were the same type and five were unique types. No single “ideal” method can be used without clinical epidemiologic investigation, but any of these techniques is helpful in providing focus to infection control practitioners assessing possible outbreaks of nosocomial infection.

Download Full-text

Oritavancin Activity against Vancomycin-Susceptible and Vancomycin-Resistant Enterococci with Molecularly Characterized Glycopeptide Resistance Genes Recovered from Bacteremic Patients, 2009-2010

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.06067-11 ◽

2011 ◽

Vol 56 (3) ◽

pp. 1639-1642 ◽

Cited By ~ 23

Author(s):

Rodrigo E. Mendes ◽

Leah N. Woosley ◽

David J. Farrell ◽

Helio S. Sader ◽

Ronald N. Jones

Keyword(s):

Resistance Genes ◽

Glycopeptide Resistance ◽

Content Type ◽

Vancomycin Resistant Enterococci ◽

Vancomycin Resistant

ABSTRACTOritavancin exhibited potent activity against vancomycin-susceptible (MIC50and MIC90, 0.015/0.03 μg/ml) andvanB-carryingE. faecalisisolates (MIC50and MIC90, 0.015 and 0.015 μg/ml). Higher (16- to 32-fold) MIC50s and MIC90s forvanA-harboringE. faecaliswere noted (MIC50and MIC90, 0.25 and 0.5 μg/ml), although oritavancin inhibited all strains at ≤0.5 μg/ml. Vancomycin-susceptible andvanB-carryingE. faeciumstrains (MIC50and MIC90, ≤0.008 and ≤0.008 μg/ml for both) were very susceptible to oritavancin, as were VanA-producing isolates (MIC50and MIC90, 0.03 and 0.06 μg/ml). Oritavancin exhibited goodin vitropotency against this collection of organisms, including vancomycin-resistant enterococci.

Download Full-text

Identification of a Novel Genomic Island Associated withvanD-Type Vancomycin Resistance in Six Dutch Vancomycin-ResistantEnterococcus faeciumIsolates

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01793-17 ◽

2018 ◽

Vol 62 (3) ◽

Cited By ~ 6

Author(s):

Janetta Top ◽

Jan C. Sinnige ◽

Ellen C. Brouwer ◽

Guido Werner ◽

Jukka Corander ◽

...

Keyword(s):

Genetic Variation ◽

Enterococcus Faecium ◽

Genomic Island ◽

Gene Clusters ◽

Genomic Comparison ◽

Variable Size ◽

Content Type ◽

Enterococcal Species ◽

Vancomycin Resistant ◽

Species Specific

ABSTRACTGenomic comparison of the first six DutchvanD-type vancomycin-resistantEnterococcus faecium(VRE) isolates with fourvanDgene clusters from other enterococcal species and anaerobic gut commensals revealed that thevanDgene cluster was located on a genomic island of variable size. Phylogenetic inferences revealed that the Dutch VRE isolates were genetically not closely related and that genetic variation of thevanD-containing genomic island was not species specific, suggesting that this island is transferred horizontally between enterococci and anaerobic gut commensals.

Download Full-text

Characterization of Vancomycin-Resistant Enterococcus faecium Isolates from the United States and Their Susceptibility In Vitro to Dalfopristin-Quinupristin

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.42.5.1088 ◽

1998 ◽

Vol 42 (5) ◽

pp. 1088-1092 ◽

Cited By ~ 55

Author(s):

G. M. Eliopoulos ◽

C. B. Wennersten ◽

H. S. Gold ◽

T. Schülin ◽

M. Souli ◽

...

Keyword(s):

United States ◽

Enterococcus Faecium ◽

Multiple Drug Resistance ◽

The United States ◽

Multiple Drug ◽

Data Set ◽

Vancomycin Resistant ◽

High Level

ABSTRACT In the course of clinical studies with the investigational streptogramin antimicrobial dalfopristin-quinupristin, isolates of vancomycin-resistant Enterococcus faecium were referred to our laboratory from across the United States. Seventy-two percent of the strains were of the VanA type, phenotypically and genotypically, while 28% were of the VanB type. High-level resistance to streptomycin or gentamicin was observed in 86 and 81%, respectively, of the VanA strains but in only 69 and 66%, respectively, of the VanB strains. These enterococci were resistant to ampicillin (MIC for 50% of the isolates tested [MIC50] and MIC90, 128 and 256 μg/ml, respectively) and to the other approved agents tested, with the exception of chloramphenicol (MIC90, 8 μg/ml) and novobiocin (MIC90, 1 μg/ml). Considering all of the isolates submitted, dalfopristin-quinupristin inhibited 86.4% of them at concentrations of ≤1 μg/ml and 95.1% of them at ≤2 μg/ml. However, for the data set comprised of only the first isolate submitted for each patient, 94.3% of the strains were inhibited at concentrations of ≤1 μg/ml and 98.9% were inhibited at concentrations of ≤2 μg/ml. Multiple drug resistance was very common among these isolates of vancomycin-resistant E. faecium, while dalfopristin-quinupristin inhibited the majority at concentrations that are likely to be clinically relevant.

Download Full-text

In Vitro Activity of Trovafloxacin against Bacteroides fragilis in Mixed Culture with either Escherichia coli or a Vancomycin- Resistant Strain of Enterococcus faecium Determined by an Anaerobic Time-Kill Technique

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.45.1.243-251.2001 ◽

2001 ◽

Vol 45 (1) ◽

pp. 243-251 ◽

Cited By ~ 16

Author(s):

Lorna E. T. Stearne ◽

Clarissa Kooi ◽

Wil H. F. Goessens ◽

Irma A. J. M. Bakker-Woudenberg ◽

Inge C. Gyssens

Keyword(s):

Escherichia Coli ◽

Resistant Strain ◽

Enterococcus Faecium ◽

Mixed Cultures ◽

E Coli ◽

Abdominal Abscesses ◽

Pure Cultures ◽

Vancomycin Resistant ◽

Time Kill

ABSTRACT To determine the efficacy of trovafloxacin as a possible treatment for intra-abdominal abscesses, we have developed an anaerobic time-kill technique using different inocula to study the in vitro killing ofBacteroides fragilis in pure culture or in mixed culture with either Escherichia coli or a vancomycin-resistant strain of Enterococcus faecium (VREF). With inocula of 5 × 105 CFU/ml and trovafloxacin concentrations of ≤2 μg/ml, a maximum observed effect (E max) of ≥6.1 (log10 CFU/ml) was attained with all pure and mixed cultures within 24 h. With inocula of 108CFU/ml, a similar E max and a similar concentration to produce 50% of E max(EC50) for B. fragilis were found in both pure cultures and mixed cultures with E. coli. However, to produce a similar killing of B. fragilis in the mixed cultures with VREF, a 14-fold increase in the concentration of trovafloxacin was required. A vancomycin-susceptible strain of E. faecium and a trovafloxacin-resistant strain of E. coli were also found to confer a similar “protective” effect on B. fragilis against the activity of trovafloxacin. Using inocula of 109 CFU/ml, the activity of trovafloxacin was retained for E. coli and B. fragilis and was negligible against VREF. We conclude that this is a useful technique to study the anaerobic killing of mixed cultures in vitro and may be of value in predicting the killing of mixed infections in vivo. The importance of using mixed cultures and not pure cultures is clearly shown by the difference in the killing of B. fragilis in the mixed cultures tested. Trovafloxacin will probably be ineffective in the treatment of infections involving large numbers of enterococci. However, due to its ability to retain activity against large cultures of B. fragilis and E. coli, trovafloxacin could be beneficial in the treatment of intra-abdominal abscesses.

Download Full-text

Vancomycin-Resistant Enterococcus faecium: Catheter Colonization, esp Gene, and Decreased Susceptibility to Antibiotics in Biofilm

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.49.12.5046-5050.2005 ◽

2005 ◽

Vol 49 (12) ◽

pp. 5046-5050 ◽

Cited By ~ 41

Author(s):

Issam I. Raad ◽

Hend A. Hanna ◽

Maha Boktour ◽

Gassan Chaiban ◽

Ray Y. Hachem ◽

...

Keyword(s):

Enterococcus Faecium ◽

Gel Electrophoresis ◽

Antibiotic Susceptibility ◽

Pulsed Field Gel Electrophoresis ◽

Molecular Characteristics ◽

Vancomycin Resistant Enterococcus ◽

Catheter Colonization ◽

Pulsed Field ◽

Vancomycin Resistant ◽

Gastrointestinal Colonization

ABSTRACT To evaluate the molecular characteristics and antibiotic susceptibility in biofilm of vancomycin-resistant Enterococcus faecium (VREF) organisms that had caused catheter-related VREF bacteremia (VREF-CRB), we compared 22 isolates causing bacteremia obtained from patients with VREF-CRB with 30 isolates from control patients with gastrointestinal colonization by VREF. Using pulsed-field gel electrophoresis, we identified 17 unique strains among the 22 VREF-CRB isolates and 23 strains among the gastrointestinal isolates. The esp gene was detected in 53% (9 of 17) of the VREF-CRB and 61% (14 of 23) of the control strains (P = 0.6). VREF-CRB produced heavier biofilm colonization of silicone disks than did control organisms (P < 0.001). Daptomycin, minocycline, and quinupristin-dalfopristin were each independently more active than linezolid in reducing biofilm colonization by VREF-CRB (P < 0.01), with daptomycin being the most active, followed by minocycline. In conclusion, the esp gene in VREF is not associated with heavy biofilm colonization or catheter-related bacteremia. In biofilm, daptomycin and minocycline were the most active antibiotics against VREF, and linezolid was the least active.

Download Full-text

VanB-Type Enterococcus faecium Clinical Isolate Successively Inducibly Resistant to, Dependent on, and Constitutively Resistant to Vancomycin

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00034-09 ◽

2009 ◽

Vol 53 (5) ◽

pp. 1974-1982 ◽

Cited By ~ 12

Author(s):

Alvaro San Millan ◽

Florence Depardieu ◽

Sylvain Godreuil ◽

Patrice Courvalin

Keyword(s):

Resistance Genes ◽

Enterococcus Faecium ◽

Constitutive Expression ◽

Pulsed Field Gel Electrophoresis ◽

Northern Hybridization ◽

Compensatory Mutation ◽

Transcription Terminator ◽

Dependent Strain ◽

Vancomycin Resistant ◽

Dipeptidase Activity

ABSTRACT Three Enterococcus faecium strains isolated successively from the same patient, vancomycin-resistant strain BM4659, vancomycin-dependent strain BM4660, and vancomycin-revertant strain BM4661, were indistinguishable by pulsed-field gel electrophoresis and harbored plasmid pIP846, which confers VanB-type resistance. The vancomycin dependence of strain BM4660 was due to mutation P175L, which suppressed the activity of the host Ddl d-Ala:d-Ala ligase. Reversion to resistance in strain BM4661 was due to a G-to-C transversion in the transcription terminator of the vanRSB operon that lowered the free energy of pairing from −13.08 to −6.65 kcal/mol, leading to low-level constitutive expression of the resistance genes from the PRB promoter, as indicated by analysis of peptidoglycan precursors and of VanXB d,d-dipeptidase activity. Transcription of the resistance genes, studied by Northern hybridization and reverse transcription, initiated from the PYB resistance promoter, was inducible in strains BM4659 and BM4660, whereas it started from the PRB regulatory promoter in strain BM4661, where it was superinducible. Strain BM4661 provides the first example of reversion to vancomycin resistance of a VanB-type dependent strain not due to a compensatory mutation in the ddl or vanSB gene. Instead, a mutation in the transcription terminator of the regulatory genes resulted in transcriptional readthrough of the resistance genes from the PRB promoter in the absence of vancomycin.

Download Full-text