<i>Objectives</i>: In 2014 probiotic supplementation (<i>Lactobacillus acidophilus and Bifidobacterium longum subspecies infantis;</i> Infloran®) was introduced as standard of care to prevent necrotizing enterocolitis (NEC) in extremely preterm infants in Norway. We aimed to evaluate the influence of probiotics and antibiotic therapy on the developing gut microbiota and antibiotic resistome in ...