In vitro conjugal transfer of tetracycline resistance from Lactobacillus isolates to other Gram-positive bacteria

Authors

  • Dirk Gevers,

    Corresponding author
    1. Laboratory of Microbiology, Faculty of Sciences, Ghent University, B-9000 Ghent, Belgium
      *Corresponding author. Present address: Bioinformatics and Evolutionary Genomics, Ghent University/VIB, B-9052 Ghent, Belgium. Tel.: +32 (9) 33 13 800; Fax: +32 (9) 33 13 809, E-mail address: dirk.gevers@ugent.be
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  • Geert Huys,

    1. Laboratory of Microbiology, Faculty of Sciences, Ghent University, B-9000 Ghent, Belgium
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  • Jean Swings

    1. Laboratory of Microbiology, Faculty of Sciences, Ghent University, B-9000 Ghent, Belgium
    2. BCCM™/LMG Bacteria Collection, Faculty of Sciences, Ghent University, B-9000 Ghent, Belgium
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*Corresponding author. Present address: Bioinformatics and Evolutionary Genomics, Ghent University/VIB, B-9052 Ghent, Belgium. Tel.: +32 (9) 33 13 800; Fax: +32 (9) 33 13 809, E-mail address: dirk.gevers@ugent.be

Abstract

The ability of 14 Lactobacillus strains, isolated from fermented dry sausages, to transfer tetracycline resistance encoded by tet(M) through conjugation was examined using filter mating experiments. Seven out of 14 tetracycline-resistant Lactobacillus isolates were able to transfer in vitro this resistance to Enterococcus faecalis at frequencies ranging from 10−4 to 10−6 transconjugants per recipient. Two of these strains could also transfer their resistance to Lactococcus lactis subsp. lactis, whereas no conjugal transfer to a Staphylococcus aureus recipient was found. These data suggest that meat lactobacilli might be reservoir organisms for acquired resistance genes that can be spread to other lactic acid bacteria. In order to assess the risk of this potential hazard, the magnitude of transfer along the food chain merits further research.

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