Detection and linkage to mobile genetic elements of tetracycline resistance gene tet(M) in Escherichia coli isolates from pigs

Background In Escherichia coli the genes involved in the acquisition of tetracycline resistance are mainly tet(A) and tet(B). In addition, tet(M) is the most common tetracycline resistance determinant in enterococci and it is associated with conjugative transposons and plasmids. Although tet(M) has been identified in E. coli, to our knowledge, there are no previous reports studying the linkage of the tet(M) gene in E. coli to different mobile genetic elements. The aim of this study was to determine the occurrence of tet(A), tet(B), and tet(M) genes in doxycycline-resistant E. coli isolates from pigs, as well as the detection of mobile genetic elements linked to tet(M) in E. coli and its possible transfer from enterococci.