Evidence of vancomycin resistance gene transfer between enterococci of human origin in the gut of mice harbouring human microbiota.
OBJECTIVE
Potential intra- and inter-species transfers of vancomycin resistance genes (vanA gene cluster) between Enterococcus strains were evaluated in the gut of heteroxenic mice harbouring a human microbiota.


METHODS
Mice colonized with a stable population of E. faecium 64/3 or E. faecalis JH2-2 recipient strain and harbouring an enterococci-free human microbiota were obtained. Donor strain E. faecium HC-VI2 of clinical origin was administered orogastrically to these mice and transfers were evaluated over time in faecal samples.


RESULTS
Only intraspecies transfers were detected in the digestive tract (DT) of mice harbouring a human microbiota. E. faecium 64/3 transconjugants were detected at several sampling times over the 60 day experiment to levels up to 10(3) cfu/g of faeces, but they did not steadily colonize the DT.


CONCLUSIONS
Here, we show for the first time that transfer of the vanA gene cluster can occur between Enterococcus strains in the DT colonized with a human microbiota and in the absence of selective pressure. The colonization properties of other enterococci transconjugants and the influence of vancomycin intake should be further investigated since transfers in the DT of animals and humans might contribute to emergence and dissemination of new vancomycin-resistant bacteria.
Mater
Denis D G
DD
Unité d'Ecologie et de Physiologie du Système Digestif, Institut National de la Recherche Agronomique, 78352 Jouy-en-Josas cedex, France.
Langella
Philippe
P
Corthier
Gérard
G
Flores
María José
MJ
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics; D019729:Carbon-Oxygen Ligases / Q000235:genetics; D013293:Enterococcus faecalis / Q000187:drug effects / Q000235:genetics*; D016984:Enterococcus faecium / Q000187:drug effects / Q000235:genetics*; D005243:Feces / Q000382:microbiology; D041981:Gastrointestinal Tract / Q000382:microbiology*; D022761:Gene Transfer, Horizontal; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology; D006801:Humans; D051379:Mice; D008809:Mice, Inbred C3H; D023421:Models, Animal; D020713:Vancomycin Resistance / Q000235:genetics*
D001426:Bacterial Proteins; C071437:VanA ligase, Bacteria; D019729:Carbon-Oxygen Ligases