Development of antibiotic resistome in premature infants. Premature gut microbiome

Preterm birth is a major cause of neonatal mortality. The gut microbiome is a crucial aspect in infants' health, and is prone to dysbiosis in preterm infants, especially with antibiotic exposure. Understanding antibiotics' effects on the gut microbiome is vital for developing strategies to support healthy microbiome development. We analyzed gut microbiome samples from a prospective cohort of 100 preterm infants. Stool samples were collected weekly during hospitalization, at 6 months and 1 year. Clinical data on antibiotic use and feeding were incorporated. To analyze the impact of antibiotic treatment, we compared infants who did not receive any antibiotics (n=31) with those who received empirical treatment after birth without subsequent antibiotic treatment (n=58). Antibiotic treatment significantly altered gut microbiome composition and increased antibiotic resistance gene abundance, particularly during early weeks of life. Despite diminishing over time, the clinical implications of the effects remain uncertain and will require further explorations. Human milk provided a protective effect, promoting beneficial bacteria like Actinobacteriota, and beneficial HMO metabolizing genes, while reducing antibiotic resistance genes. These findings emphasize the importance of judicious antibiotic use and promoting human milk feeding to support healthy gut microbiome development in preterm infants.