<qa>  What is the differential effect of narrow spectrum and broad spectrum on the nasal and gastrointestinal microbioDifferential effect of narrow spectrum flucloxacillin and broad spectrum ceftriaxone on the nasal and gastrointestinal microbiome from nasal swabs and stool samples collected within 48 hours, after 7-14 days, 3 months and 1 year after starting antibiotics. 