Impact of bovine lactoferrin fortification on pathogenic organisms to attenuate the risk of infection for infants

Abstract

Cronobacter and Pseudomonas spp. are pathogenic organisms that are associated with neonatal morbidities such as bacteremia, sepsis, necrotizing enterocolitis (NEC), and infant meningitis. Lactoferrin (Lf) is a known bactericidal component of fresh human milk. Infants receiving formula or pasteurized donor milk however may not be receiving lactoferrin at same concentration as mother's own milk, so it is beneficial to understand an exogenous role for dairy bovine lactoferrin (bLf). Our aim was to investigate the potential for bLf to provide a novel way to inhibit the growth of these harmful organisms in infant feeding. Subinhibitory doses, Disc-diffusion assay, Minimum Inhibitory Concentrations (MIC), Minimum Bactericidal Concentrations (MBC), and challenge experiments in powder formula were used to investigate the effects of bLf on sepsis-causing bacteria such as C. muytjensii (ATCC-51329), C. sakazakii (ATCC-12868), C. sakazakii (ATCC-9027), P. aeruginosa (ATCC-19429), and P. aeruginosa (ATCC-9027). MIC and MBC of bLf in the range of 12.5–31.25 μM were sufficient to achieve a 3 log reduction of Cronobacter in nutrient broth (P < 0.0001). Similarly, minimum concentrations of 43.75–118.75 μM bLf against Pseudomonas (P < 0.0001) were demonstrated. After bactericidal concentrations were determined, higher resistant strains such as C. sakazakii (ATCC-12868) and P. aeruginosa (ATCC-19429) were chosen as ideal candidates for the bLf supplementation challenge studies. The bLf reduced the C. sakazakii (ATCC-12868) by 3.3 log at 35 °C, 2.8 log at 23 °C, and 1.9 log at 4 °C (P < 0.0001), whereas P. aeruginosa (ATCC-19429) showed 2.4 log reduction at 35 °C, 2.8 log at 23 °C (P < 0.0001), and 1.8 log at 4 °C (P < 0.01). Results indicated that bLf could effectively inactivate the sepsis-causing organisms in reconstituted infant formula and in bacterial growth media. Fortification of infant formula with bLf may address the problems of spoilage/contamination issues and provide a safety measure for feeding infants without mother's own milk.