If mothers own milk or donor human milk is not available, 1 sachet will be added to a minimum of 1 mL of sterile water or formula (in formula fed babies) once a day. All empty sachets will be placed into biohazard container. Placebo sachet will be made of 0.3 g maltodextrin and be administered to the control group in the same manner. If the infant is placed NPO, the study drug will be stopped and restarted together with refeeding. Both probiotic and placebo will be packaged as single dose sachet. They will be maintained, blinded and dispensed by the pharmacists at the study sites, who will be the only ones knowing the subject assignment.