Sample collection

Pig samples were obtained at a commercial slaughterhouse (Danish Crown, Ringsted, Denmark), immediately following controlled atmosphere stunning by CO₂ but prior to euthanasia. Each animal (n = 30) was sampled behind one ear, in the nose and on the ventral and dorsal skin surface by use of individual ESwabs (Copan Diagnostics Inc., Murrieta, CA, USA) for a total of 120 samples. The ear was sampled by three gliding motions behind the pinna, the nose by a rotary motion ~1 cm inside each of the nares and on the two skin surfaces by three consecutive ~3 cm strokes in the same location. All handling of animals was in accordance with regulations from the Danish Ministry of Justice.

Mink samples, some positive and some negative for MRSA were acquired from routine diagnostics of clinical mink sent to DTU-VET. Swab samples from throat were obtained as described by Hansen et al.².

A Staphylococcus control was made by a mixing cultures of S. aureus (both resistant and sensitive to methicillin), S. cohnii, S. delphini, S. equorum, S. epidermidis, S. haemolyticus, S. hyicus, S. schleiferi, S. sciuri, S. succinus, and S. xylosus equally, which subsequently was subjected to the same purification, PCR-amplification and sequencing procedure as the pig and mink samples.