Keywords
Infant very low birth weight
How to Cite
Abstract
Mortality in very low birth weight (VLBW) infants accounts for up to 50%-70% of neonatal mortality and up to 25%-30% of infant mortality. Despite the global increase in survival rates, this population continues to present an elevated risk of developing long-term neurodevelopmental delays, chronic lung disease, malnutrition, and visual and hearing impairments. The intestinal microbial composition of VLBW infants differs from that of full-term newborns and is typically dominated by pathobionts. In this study, we characterized the bacterial composition of the gut microbiota of VLBW infants born in a public, tertiary referral maternity hospital in Montevideo, Uruguay, through full-length 16S rRNA gene sequencing using Oxford Nanopore technologies. We described a high predominance of Klebsiella pneumoniae and Escherichia coli in these newborns. By sequencing stool samples at two different times during hospitalization, we showed that the diversity of the microbial community increases over time, with a higher relative abundance of Bacteroides and Veillonella. Furthermore, we described the effect of prolonged antibiotic exposure on the microbial composition. Different species of the genus Klebsiella, along with Escherichia coli, Enterobacter cloacae, Citrobacter freundii, and Veillonella parvula, were observed in higher relative abundance in patients treated with antibiotics for more than five days. Collectively, our findings shed light on the development and establishment of microbial communities in early life in South America. Our results point to postnatal antibiotics as a primary factor orchestrating this process. Integrating considerations of microbial community health into the clinical care of preterm infants is crucial to improving long-term development.
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Copyright (c) 2026 Catalina Vaz Ferreira, Josefina Vera, Mario Moraes, Nadia Riera