Gentamicin resistance gene transfer from Enterococcus faecalis and E. faecium to Staphylococcus aureus, S. intermedius and S. hyicus

Transfer of gentamicin resistance from Enterococcus faecalis and E. faecium to Staphylococcus aureus, S. hyicus and S. intermedius was accomplished by filter mating. Transfer from E. faecalis was plasmid mediated and a probe to the gentamicin resistance gene aac(6′)- aph(2″) hybridized to HindIII fragments of various sizes (7.5, 6.2 and 4.7 kbp) of these plasmids. Transfer from E. faecium was apparently to the chromosome in 9 of 10 instances with HindIII fragments of 3.3 or 3.0 kbp hybridizing to the probe. These results are consistent with transposon mediated resistance. Plasmid transfers to S. intermedius were at much lower frequencies than to S. aureus or to S. hyicus but presumed transposon transfer direct to the chromosome was equal in all three species.