Comparative DNA Analysis of Two
            <i>vanA</i>
            Plasmids from
            <i>Enterococcus faecium</i>
            Strains Isolated from Poultry and a Poultry Farmer in Norway

Sletvold, Hege; Johnsen, Pål Jarle; Simonsen, Gunnar Skov; Aasnæs, Bettina; Sundsfjord, Arnfinn; Nielsen, Kaare M.

doi:10.1128/aac.00557-06

Cited by 57 publications

(52 citation statements)

References 20 publications

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“…Furthermore, the ABC transport genes are also present in several other plasmids from VRE originating from broilers in Norway (Fig. 1, Sletvold et al, 2008;Sletvold et al, 2007). All annotated genes in the six plasmids are listed in Supplementary material S1 where the genes in the 5.9 kb area unique to the four plasmids of the isolates with elevated MIC of narasin are highlighted in bold text.…”

Section: Resultsmentioning

confidence: 99%

“…1. Comparison of the six plasmids sequenced in this study and pVEF2, pVEF3 and PVEF4 from vancomycin resistant enterococci isolated from broilers in Norway (Sletvold et al, 2008(Sletvold et al, , 2007(Sletvold et al, , 2010. The genes coding for vancomycin resistance are situated between 15 and 22 kbp whereas the genes coding for the ABC-transporter putatively conferring elevated MIC of narasin are located between 36 and 40 kbp.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Transferable genes putatively conferring elevated minimum inhibitory concentrations of narasin in Enterococcus faecium from Swedish broilers

Nilsson

Myrenås

Ågren

2016

Veterinary Microbiology

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Transferable genes putatively conferring elevated minimum inhibitory concentrations of narasin in Enterococcus faecium from Swedish broilers

Nilsson

Myrenås

Ågren

2016

Veterinary Microbiology

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“…antitoxin maintenance systems highly similar to that of pSM19035 have been seen in Enterococcus faecium and Enterococcus faecalis (32,54). The instability of cfr within this greater chromosomal insertion locus in the absence of selective pressure selects for recombination events whereby the gene is excised and may potentially be transmitted horizontally.…”

Section: Fig 5 Serial Passage Of Cm05 Under Nonselective Conditions mentioning

confidence: 86%

Genetic Environment and Stability of cfr in Methicillin-Resistant Staphylococcus aureus CM05

Locke

Rahawi²,

LaMarre

et al. 2012

Antimicrob Agents Chemother

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The Cfr methyltransferase confers resistance to many 50S ribosomal subunit-targeted antibiotics, including linezolid (LZD), via methylation of the 23S rRNA base A2503 in the peptidyl transferase center. Methicillin-resistant Staphylococcus aureus strain CM05 is the first clinical isolate documented to carry cfr. While cfr is typically plasmid borne, in CM05 it is located on the chromosome and is coexpressed with ermB as part of the mlr operon. Here we evaluated the chromosomal locus, association with mobile genetic elements, and stability of the cfr insertion region in CM05. The cfr-containing mlr operon is located within a 15.5-kb plasmid-like insertion into 23S rRNA allele 4. The region surrounding the cfr gene has a high degree of sequence similarity to the broad-host-range toxin/antitoxin multidrug resistance plasmid pSM19035, including a second ermB gene downstream of the mlr locus and istAS-istBS. Analysis of several individual CM05 colonies revealed two distinct populations for which LZD MICs were either 8 or 2 g/ml. In the LZD s colonies (designated CM05⌬), a recombination event involving the two ermB genes had occurred, resulting in the deletion of cfr and the 3= flanking region (cfr-istAS-istBS-ermB). The fitness advantage of CM05⌬ over CM05 (though not likely due to the cfr deletion itself) results in the predominance of CM05⌬ in the absence of selective pressure. Minicircles resulting from the ermB recombination event and the novel association of cfr with the pSM19035 plasmid system support the potential for the continued dissemination of cfr. R esistance to linezolid (LZD) was reported shortly after its introduction into the clinic and included both staphylococcal and enterococcal strains carrying G2576T mutations in one or more alleles of the domain V-encoding region of 23S rRNA genes (21, 57). These mutations perturb the conformation of the peptidyl transferase center, which is the target of oxazolidinones in the 50S ribosomal subunit (30,52,59). More recently, LZD resistance has been linked to additional mutations identified in the genes encoding 50S ribosomal proteins L3 and L4 (34, 58). Most problematic has been the identification of cfr, a horizontally transferable gene encoding a ribosomal methyltransferase that confers resistance to multiple classes of antibacterial agents targeting the peptidyl transferase center by posttranscriptional modification of the 23S rRNA (29). Recent studies have shown that Cfr methylates carbon 8 of nucleotide A2503 (20), thereby conferring a PhLOPS A phenotype characterized by decreased binding of phenicols, lincosamides, oxazolidinones, pleuromutilins, and streptogramin A class antibiotics (29,37,56), as well as of 16-membered ring macrolides (55), to Cfr-methylated ribosomes. Of further concern is the low fitness cost associated with Cfr methylation (31) and the documentation of clinical cfr strains possessing co-occurring mutations in 23S rRNA (14) and ribosomal proteins L3 (36) and L4 (5). The need to maintain potency against strains with cfr and/or other LZ...

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“…Exchange of resistant strains among different ecosystems is less probable due to the supposed ecovar association, especially among hospital-associated E. faecium strains (see chapter 5), although dissemination across host barriers of vancomycin-and multi-resistant enterococci was described anecdotally, especially for the less strongly host-adapted E. faecalis strains (Manson et al, 2003a;Manson et al, 2003b;Manson et al, 2004;Agerso et al, 2008;Larsen et al, 2010;Hammerum et al, 2010;Freitas et al, 2011a). Vancomycin resistance among enterococci most probably spreads via a dissemination of mobile genetic elements of variants of the vanA-type element Tn1546 mostly located on mobilizable or conjugative plasmids (Sletvold et al, 2007;Novais et al, 2008;Sletvold et al, 2008;Freitas et al, 2009;Rosvoll et al, 2009;Sletvold et al, 2010;Laverde Gomez et al, 2011;Werner et al, 2011b;Freitas et al, 2011b). In vitro transfer of vanA plasmids has been determined in a number of studies (Werner et al, 1997;van den Braak et al, 1998;Werner et al, 2010b) and transfer in vivo in digestive tracts of animals and human volunteers was also shown (Moubareck et al, 2003;Lester et al, 2006;Lester and Hammerum 2010).…”

Section: Localization and Spread Of Vana-and Vanb-type Resistancementioning

confidence: 99%

Current Trends of Emergence and Spread of Vancomycin-Resistant Enterococci

Werner¹

2012

Antibiotic Resistant Bacteria - A Continuous Challenge in the New Millennium

184

229

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Comparative DNA Analysis of Two vanA Plasmids from Enterococcus faecium Strains Isolated from Poultry and a Poultry Farmer in Norway

Cited by 57 publications

References 20 publications

Transferable genes putatively conferring elevated minimum inhibitory concentrations of narasin in Enterococcus faecium from Swedish broilers

Transferable genes putatively conferring elevated minimum inhibitory concentrations of narasin in Enterococcus faecium from Swedish broilers

Genetic Environment and Stability of cfr in Methicillin-Resistant Staphylococcus aureus CM05

Current Trends of Emergence and Spread of Vancomycin-Resistant Enterococci

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