Fig. 4

Source tracking of infant gut microbiome in the NICU. A Species-FEAST and B SNV-FEAST applied to infants in the NICU. Each bar represents one sampling day in the NICU stay of an infant. Infants 3 and 6 stayed in the same room, but at different times. The same applies to Infants 12 and 18. The contribution of a different room was determined by using samples from Infant 12’s room for Infants 3 and 6, and samples from Infants 6’s room for Infants 12 and 18 for each of the categories of surfaces per infant: touched surface, sink basin, or floor and isolette top surface. The asterisks represent the result of a paired Wilcoxon signed rank test indicating whether the total contribution of surfaces from the infant’s own room was higher than contributions from the other room. Iterative swapping of the infant sink and each potential source for source tracking with C species-FEAST and D SNV-FEAST. The first column shows source tracking results in which the infant was treated as the sink. In each column after the first column, a different environmental source was swapped with the infant and treated as a sink. The brackets indicate the pairs of results that are compared using a paired Wilcoxon signed rank test. For all results, the following symbols represent the results of the statistical test: **** for p-value < 0.0001, *** for p-value < 0.001, ** for p-value < 0.001, * for p-value < 0.05, and n.s. for p-value > 0.05