In vitro conjugal transfer of tetracycline resistance from Lactobacillus isolates to other Gram-positive bacteria.
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.
Gevers
Dirk
D
Laboratory of Microbiology, Faculty of Sciences, Ghent University, B-9000 Ghent, Belgium. dirk.gevers@ugent.be
Huys
Geert
G
Swings
Jean
J
D000818:Animals; D001483:Base Sequence; D003227:Conjugation, Genetic; D004269:DNA, Bacterial / Q000235:genetics; D013293:Enterococcus faecalis / Q000187:drug effects / Q000235:genetics; D005516:Food Microbiology; D005798:Genes, Bacterial; D006094:Gram-Positive Bacteria / Q000187:drug effects* / Q000235:genetics*; D007778:Lactobacillus / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D013294:Lactococcus lactis / Q000187:drug effects / Q000235:genetics; D008461:Meat Products / Q000382:microbiology; D010957:Plasmids / Q000235:genetics; D013211:Staphylococcus aureus / Q000187:drug effects / Q000235:genetics; D013753:Tetracycline Resistance / Q000235:genetics*
D004269:DNA, Bacterial