Lactoferrin and prevention of late-onset sepsis in the pre-term neonates

Late-onset sepsis (LOS) affects a large proportion of pre-term neonates in neonatal intensive care units (NICUs) worldwide, with high morbidity and related mortality, and frequent occurrence of severe late neurodevelopmental impairment. Due to the frequency, severity and difficulties in early diagnosis and prompt therapy, prevention is crucial for decreasing the burden of infection-related complications in NICUs. It is well known that feeding with fresh maternal milk, hygiene measures and the cautious use of H2-blockers are related with a decreased risk of developing sepsis. However, evidence from randomised clinical trials exists only for fluconazole in the prevention of fungal infections in the NICU. Lactoferrin is the main whey protein in mammalian milk, and is involved in innate immune host defences. Notably, human lactoferrin can be found at increased concentrations in colostrum and in milk from mothers of premature neonates. Human (hLF) and bovine lactoferrin (bLF) share a high (77%) amino-acid homology, and the same N-terminal peptide responsible for antimicrobial activity, called lactoferricin. In vitro, bLF shows potent direct antimicrobial activity against all types of pathogens, which occurs via anti-cell wall actions and leads to disintegration of the micro-organism's membranes. bLF is also synergistic with many antimicrobials and antifungals, and promotes growth and differentiation of the immature gut. Based on this background data, a randomised clinical trial was recently conducted in very low birth weight pre-term neonates given bLF alone or with the probiotic Lactobacillus GG. The aim of the trial was to assess the ability of bLF to prevent late-onset sepsis of any origin in the studied infants during their stay in the NICU. This article discusses the preliminary data from this study, along with the proposed mechanisms of action of bLF in pre-term infants.