Nurses will collect the stool samples at 3 time points: prior to initiation, 1 week after and 4 weeks after probiotic or placebo administration is commenced. "Stool" will be collected directly from the infant's ostomy bag and diaper with a sterile spatula. As soon as a sample is collected, the nurse will contact the investigators. The samples will then be placed in a laboratory freezer (-80°C) within 24 hours of collection. Batched samples will be transported to the University of Calgary Genomics laboratory for subsequent microbiome processing.