Impact of nasopharyngeal microbiota on the developmentof respiratory tract diseases

Abstract Knowledge of whether and how respiratory microbiotacomposition can prime the immune system and providecolonisation resistance, limiting consecutive pathobiont overgrowthand infections, is essential to improving the preventionand therapy of respiratory disorders. Modulation of dysbioticecosystems or reconstitution of missing microbes might be apossible measure to reduce respiratory diseases. The aim ofthis review is to analyse the role of nasopharyngeal microbiotain the development of respiratory tract disease in paediatricagesubjects. PubMed was used to search for all studies publishedover the last 15 years using the following key words:Bmicrobiota^ or Bmicrobioma^ and Bnasopharyngeal^ orBrespiratory^ or Bnasal^ and Bchildren^ or Bpaediatric^ orBinfant^. Analysis of the literature showed that respiratorymicrobiota can regulate health and disease development inthe respiratory tract. Like the gut microbiota, the respiratorymicrobiota is established at birth, and early respiratory microbiotacomposition determines bacterial succession patternsand respiratory health in children. Protective and dangerousbacteria have been identified, and this can be considered thebase for developing new approaches to diseases that respondpoorly to traditional interventions. Reconstitution of missingmicrobes can be achieved by the administration of pre- andprobiotics. Modulation of respiratory microbiota by favouring colonisation of the upper respiratory tract by beneficial commensalscan interfere with the proliferation and activity ofresident pathobionts and is a possible new measure to reducethe risk of disease. However, further studies are needed becausea deeper understanding of these and related issues canbe transferred to clinical practic