Retrospective detection of methicillin resistant and susceptible Staphylococcus aureus ST398 in Danish slaughter pigs

This retrospective study documents the first detection in Danish pigs of methicillin resistant and susceptible variants of the Staphylococcus aureus lineage ST398, which was previously described among pigs, pig farmers and veterinary staff in The Netherlands as well as in human patients and infected animals in Europe. Ten out of 100 pigs tested were shown to carry ST398 in the nasal cavity and two out of three farms tested were positive. The 10 porcine ST398 isolates had spa type t034 (n=9) and t1793 (n=1), and were resistant to erythromycin, clindamycin and tetracycline in addition to penicillin. The detection of ST398 in Danish pigs suggests that this new emerging zoonotic bacterium is rapidly spreading in the pig population in Europe.