Loss of cutaneous microbial diversity during first 3 weeks of life in very low birthweight infants.

Neonatal sepsis (NS) is a frequent problem in neonatal intensive care, especially in preterm and very low birthweight (VLBW) infants. The objective of the study was to characterize the cutaneous bacterial microbiome in VLBW infants treated in the neonatal intensive care unit (NICU). Non-invasive skin microbiome specimens were taken repeatedly from 12 VLBW infants during treatment in NICU starting on the first day of life. All infants received benzylpenicillin and netilmicin during the first 1-5 postnatal days. Samples were also collected from incubators. High cutaneous microbial diversity was present at birth in 11 of 12 of the infants, but the diversity decreased substantially after the first weeks of life in all infants regardless of their infection status. After the loss of diversity, one Staphylococcus operational taxonomic unit dominated the skin microbiome. Recovery of microbial diversity was seen in six of 12 neonates. The microbiome of incubators showed typical environmental bacterial genera. Maternal antibiotic treatment, the aetiology of the preterm birth or being born by C-section did not appear to affect the diversity of skin microbiota at birth, and no correlation was found between cutaneous microbiome and NS.