Probiotics seem to be good for everybody. That even includes extremely premature babies.
Dr. Mohamad Al-Hosni along with colleagues from three medical centers, gave supplemental feeding of probiotics to fifty extremely premature babies each weighing two pounds two ounces or less.
Supplementation was 500 million colony-forming units (CFU) of Lactobacillus rhamnosus GG and 500 CFU of Bifidobacterium infantis once a day until the babies were discharged from the hospital or until they reached thirty-four weeks postmenstrual age. Fifty-one extremely premature babies did not receive supplemental feeding of probiotics.
"Results showed superior weight gain in infants who received the probiotics even though the average daily volume of their feedings was less than infants in the control group. There were no statistically significant differences in other complications of prematurity such as sepsis or necrotising enterocolitis. In addition, no side effects were seen as a result of probiotic supplementation, according to Dr Al-Hosni, an assistant professor of paediatrics at Saint Louis University School of Medicine in the division of neonatal-perinatal medicine at SSM Cardinal Glennon Children's Medical Center."
http://www.virtualmedicalcentre.com/news/Probiotics-help-extremely-premature-infants-gain-weight/14977