Another weakness is that this study monitors colonisation at a single time-point, although colonisation is known to be variable over time and it should be differentiated between persistent and intermitted carriers [20]. Only nasal swab samples were used to determine S. aureus colonization status, as the study protocol did not include swabbing of extranasal body sites. While the prevalence might be underestimated by using nasal swabs, we assume our final sample of S. aureus to be representative of all carriage. We also assume that antimicrobial resistance patterns in the commensal flora of the nose are comparable with isolates of pathogenic staphylococci. However, for purposes of empirical treatment, data on resistance of pathogenic strains would also be required.