Fortification With Bovine Colostrum Enhances Antibacterial Activity of Human Milk
Human milk (HM) is the optimal diet for neonates, but it does not provide enough nutrients for preterm infants. HM fortifiers based on highly processed bovine milk (BMFs) are routinely used for preterm infants despite the risks of causing gut dysfunction and systemic infection. Bovine colostrum (BC) contains high levels of bioactive and immune factors, including IgG, lactoferrin, osteopontin, insulin-like growth factor, and epidermal growth factor. Gently processed bovine colostrum as a fortifier (BCF) may show enhanced antimicrobial activity against pathogens that commonly cause neonatal sepsis and protect against infection and inflammation. Pasteurized HM samples were aliquoted into 3 fractions: unfortified HM and HM fortified with either BMF or BCF. The samples were analyzed for pH, lactoferrin concentrations, and antimicrobial activities in vitro against Staphylococcus epidermidis, Escherichia coli, and Enterococcus faecalis. HM+BCF had a lower pH and higher lactoferrin levels than HM+BMF, with HM being intermediate. Relative to infant formula, HM decreased the growth of S. epidermidis, E. coli, and E. faecalis. The addition of BMF abolished the antimicrobial effect of HM against S. epidermidis and E. faecalis but not E. coli. By contrast, the addition of BCF into HM enhanced antimicrobial activity against S. epidermidis and E. coli, relative to unfortified HM. HM+BCF was superior to HM+BMF in inhibiting growth of all tested bacteria. Conclusion: A conventional fortifier decreased whereas BC fortification enhanced in vitro antimicrobial activity of HM. This effect may be derived from the high levels of antimicrobial factors found in BC, including lactoferrin. BCF may be a better fortifier than BMF for preterm infants.