Nasal microbiota and symptom persistence in acute respiratory tract infections in infants

Neumann, Roland P.; Hilty, Markus; Xu, Binbin; Usemann, Jakob; Korten, Insa; Mika, Moana; Müller, Loretta; Latzin, Philipp; Frey, Urs

This study was performed as part of the Basel Bern Infant Lung Development (BILD) cohort study [20] . The study was approved by the local ethics committees (Ethics Committee of the Canton of Bern and Ethics Committee of Basel (EKBB)). Informed written parental consent was obtained prior to enrolment in the study. Infants from this prospective birth cohort were followed by weekly standardised telephone interviews, as previously described [21] . Parents were advised to call the study team as soon as their child presented with symptoms of an ARI, which was defined as more than two consecutive days of cough and/ or wheeze accompanied by fever (>38°C), rhinitis, otitis media or pharyngitis [20] . Nasal swabs were taken at the onset of the ARI (swab A) and 3 weeks later (swab B), as described in the supplementary methods. Nasal swabs were analysed by real-time PCR assays targeting five different respiratory viruses (human rhinovirus/enterovirus (HRV/EV), respiratory syncytial virus (RSV), human metapneumovirus (HMPV), human coronavirus (HCoV) and human parainfluenza virus (HPIV)), which have been shown to be the most common viruses in our population [2] . Details on the methods of viral analysis are provided in the supplementary methods. The results of viral studies of a subset of infants, also reported in this study, have been reported previously [2] . Infants were regarded to be at an increased risk for atopy if the infants' mother, father or siblings were suffering from eczema, allergic rhinitis or allergic asthma. Extensive data on several host factors were collected using questionnaires [20] .