<p><i>Objectives - </i>To systematically review the impact of antibiotic therapy in the neonatal period on changes in the gut microbiota and/or antibiotic resistance development. <p><i>Methods - </i>Data sources were PubMed, Embase, Medline and the Cochrane Database, supplemented by manual searches of reference lists. Randomized controlled trials (RCTs) and observational studies were included if ...