The aim of this project is to assess the possible role of non-pathogenic food-associated Gram-positive bacteria in the dissemination of antibiotic resistance genes throughout human populations. For this purpose, a collection of tetracycline resistant strains will be collected encompassing Lactobacillus, Lactococcus, enterococcus and coagulase-negative staphylococci. These strains will be analyzed for the horizontal transferability of tetracycline resistance genes, the identity of these genes, and their phylogenetic relatitonship.