Fig. 3

Temporal distribution of gut microbiota phases, change in infant weight and meconium clearance. a All rectal samples from 95 preterm and 25 full-term infants are plotted against post menstrual age, stratified by subject and sorted by gestational age at birth. Samples for preterm infants include those collected weekly from birth through discharge. Samples for full-term infants include the first sample after birth (collected at ≤ 20 DOL) and a second sample, collected ≤ 50 DOL. Microbiota phases (P1, red circle; P2, orange circle; P3, green circle), birth (gray diamond), stool transition (blue arrowhead), and NEC diagnosis (black square) at discharge are also indicated. Change in weight Z-score from birth to discharge, and elemental feeding requirements (maroon E) at discharge for preterm infants are indicated in the right margin. The lowest to greatest change in weight Z-score from birth to discharge spans the spectrum from red to green. In all infants, except for J94F4, the total weight change in weight Z-score from birth to discharge was negative. Weight Z-score changes in full-term infants were both positive and negative, and negative changes tended to be smaller than those observed in preterms. b Day of life of stool transition and phase transition for 38 preterm subjects in phase one (P1) at the time of their first microbiota sample. The relationship between day of life (DOL) for the initial transition out of P1 and from meconium to normal infant stool was modeled by linear regression. These results demonstrate a highly significant association between the transition out of P1 and from meconium to normal infant stool that is independent of PMA or prematurity, suggesting that the P1 and meconium microbiota are closely associated