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Tn6198, a novel transposon containing the trimethoprim resistance gene dfrG embedded into a Tn916 element in Listeria monocytogenes

Bertsch, David ; Uruty, Anaïs ; Anderegg, Janine ; Lacroix, Christophe ; Perreten, Vincent ; Meile, Leo

In: Journal of Antimicrobial Chemotherapy, 2013, vol. 68, no. 5, p. 986-991

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    Titre
    • Tn6198, a novel transposon containing the trimethoprim resistance gene dfrG embedded into a Tn916 element in Listeria monocytogenes
    Auteur
    • Bertsch, David. Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, ETH Zurich, Schmelzbergstrasse 7, 8092 Zurich, Switzerland
    • Uruty, Anaïs. Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, ETH Zurich, Schmelzbergstrasse 7, 8092 Zurich, Switzerland
    • Anderegg, Janine. Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, ETH Zurich, Schmelzbergstrasse 7, 8092 Zurich, Switzerland
    • Lacroix, Christophe. Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, ETH Zurich, Schmelzbergstrasse 7, 8092 Zurich, Switzerland
    • Perreten, Vincent. Institute of Veterinary Bacteriology, University of Bern, Länggass-Strasse 122, 3012 Bern, Switzerland
    • Meile, Leo. Laboratory of Food Biotechnology, Institute of Food, Nutrition and Health, ETH Zurich, Schmelzbergstrasse 7, 8092 Zurich, Switzerland
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • Journal of Antimicrobial Chemotherapy, 2013, vol. 68, no. 5, p. 986-991. Oxford University Press
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:290815
    Summary
    Objectives To characterize Tn6198, a novel conjugative transposon from the clinical Listeria monocytogenes strain TTH-2007, which contains the tetracycline and trimethoprim resistance genes tet(M) and dfrG, respectively, and to assess its transferability in vitro and in situ. Methods The complete sequence of Tn6198 was determined using a primer walking strategy. Horizontal gene transfer studies were performed by filter matings, as well as on the surface of smear-ripened cheese and smoked salmon. The presence of Tn916-like circular intermediates was determined by PCR. Antibiotic resistance was determined by the broth microdilution method and microarray hybridization. Results Sequencing of Tn6198 revealed that a 3.3 kb fragment containing dfrG was integrated between open reading frames 23 and 24 of Tn916. Furthermore, an additional copy of Tn916 was present in L. monocytogenes TTH-2007. Both elements were transferred simultaneously and separately in vitro to recipients L. monocytogenes 10403S and Enterococcus faecalis JH2-2 by conjugation, resulting in either tetracycline- and trimethoprim-resistant or solely tetracycline-resistant transconjugants. On the surface of cheese and salmon, only L. monocytogenes 10403S transconjugants were detected. Conclusions This study reports the first Tn916-like element associated with a trimethoprim resistance gene, as well as the first fully characterized transposon conferring multidrug resistance in L. monocytogenes. This is of concern, as trimethoprim is administered to listeriosis patients with β-lactam allergy and as Tn6198 has a large potential for dissemination, indicated by both intra-species and inter-genus transfer