Journal article
Host range of enterococcal vanA plasmids among Gram-positive intestinal bacteria
Robert Koch Institute1
University of Porto2
Hospital Ramon y Cajal3
University of Tromsø – The Arctic University of Norway4
Statens Serum Institut5
National Food Institute, Technical University of Denmark6
Division of Microbiology and Risk Assessment, National Food Institute, Technical University of Denmark7
Hospital Universitario Marques de Valdecilla8
University Medical Centre Utrecht9
OBJECTIVES: The most prevalent type of acquired glycopeptide resistance is encoded by the vanA transposon Tn1546 located mainly on transferable plasmids in Enterococcus faecium. The limited occurrence in other species could be due to the lack of inter-species transferability and/or stability of Tn1546-containing plasmids in other species.
We investigated the in vitro transferability of 14 pre-characterized vanA-containing plasmids hosted by E. faecium (n = 9), Enterococcus faecalis (n = 4) and Enterococcus raffinosus (n = 1) into several enterococcal, lactobacterial, lactococcal and bifidobacterial recipients. METHODS: A filter-mating protocol was harmonized using procedures of seven partner laboratories.
Donor strains were mated with three E. faecium recipients, three E. faecalis recipients, a Lactobacillus acidophilus recipient, a Lactococcus lactis recipient and two Bifidobacterium recipients. Transfer rates were calculated per donor and recipient. Transconjugants were confirmed by determining their phenotypic and genotypic properties.
Stability of plasmids in the new host was assessed in long-term growth experiments. RESULTS: In total, 282 enterococcal matings and 73 inter-genus matings were performed and evaluated. In summary, intra-species transfer was far more frequent than inter-species transfer, if that was detectable at all.
All recipients of the same species behaved similarly. Inter-genus transfer was shown for broad host range control plasmids (pIP501/pAMβ1) only. Acquired resistance plasmids remained stable in the new host. CONCLUSIONS: Intra-species transfer of enterococcal vanA plasmids was far more frequent than transfer across species or genus barriers and may thus explain the preferred prevalence of vanA-containing plasmids among E. faecium.
A reservoir of vanA plasmids in non-enterococcal intestinal colonizers does not seem to be reasonable.
Language: | English |
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Publisher: | Oxford University Press |
Year: | 2010 |
Pages: | 273-82 |
ISSN: | 14602091 and 03057453 |
Types: | Journal article |
DOI: | 10.1093/jac/dkq455 |
ORCIDs: | Jensen, Lars Bogø |