A prospective multicenter , double-blinded , placebo-controlled , randomized trial compared daily administration of a probiotic combination ( Bifidobacterium infantis , Streptococcus thermophilus , and Bifidobacterium lactis , containing 1 10 ( 9 ) total organisms ) with placebo ( maltodextrin ) in infants born before 32 completed weeks ' gestation weighing < 1500 g.