Probiotics and necrotizing enterocolitis.

Probiotics for the prevention of necrotizing enterocolitis have attracted a huge interest. Combined data from heterogeneous randomised controlled trials suggest that probiotics may decrease the incidence of NEC. However, the individual studies use a variety of probiotic products, and the group at greatest risk of NEC, i.e., those with a birth weight of less than 1000 g, is relatively under-represented in these trials so we do not have adequate evidence of either efficacy or safety to recommend universal prophylactic administration of probiotics to premature infants. These problems have polarized neonatologists, with some taking the view that it is unethical not to universally administer probiotics to premature infants, whereas others regard the meta-analyses as flawed and that there is insufficient evidence to recommend routine probiotic administration. Another problem is that the mechanism by which probiotics might act is not clear, although some experimental evidence is starting to accumulate. This may allow development of surrogate endpoints of effectiveness, refinement of probiotic regimes, or even development of pharmacological agents that may act through the same mechanism. Hence, although routine probiotic administration is controversial, studies of probiotic effects may ultimately lead us to effective means to prevent this devastating disease.