Nasal and oropharyngeal samples were separately plated on chromID S. aureus and chromID MRSA agar plates (bioMérieux, La Balme, France), and subsequently placed in two Mueller–Hinton (MH) broth supplemented with 6.5% NaCl. The overnight MH broth were separately subcultured onto both chromID S. aureus and chromID MRSA agar plates. All agar plates were read after 18–24 h incubation at 35–37°C according to manufacturer's instructions [23] (link). All cefoxitin resistant isolates were tested using a PCR for the presence of the mecA and nuc gene [24] (link)–[25] . All S. aureus strains were genotyped by staphylococcal protein A (spa) typing [26] (link) and multiple-locus variable-number tandem repeat analysis (MLVA) as described previously [27] (link). MLVA types (MTs) were clustered using a categorical clustering coefficient and a minimum spanning tree was constructed to display the relationships between the various MTs. MLVA complexes (MC) were assigned if two neighbouring MTs did not differ in more than one variable number tandem repeat (VNTR) locus and if at least five neighbouring MTs fulfilled this criterion.
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