Effects of powdered human milk fortifiers on the antibacterial actions of human milk

Analyzing the Responses of Enteric Bacteria to Neonatal Intensive Care Supplements

In the neonatal intensive care unit, adequate nutrition requires various enteral products, including human milk and formula. Human milk is typically fortified to meet increased calorie goals, and infants commonly receive vitamin mixes, iron supplements, and less frequently, thickening agents. We examined the growth of 16 commensal microbes and 10 pathobionts found in the premature infant gut and found that formula, freshly pasteurized milk, and donated banked milk generally increased bacterial growth. Fortification of human milk significantly elevated the growth of all microbes. Supplementation with thickeners or NaCl in general did not stimulate additional growth. Vitamin mix promoted the growth of several commensals, while iron promoted growth of pathobionts. These data indicate that pathobionts in the preterm gut have significant growth advantage with preterm formula, fortified donor milk, and supplemented iron and suggest that the choice of milk and supplements may impact the infant gut microbiota.

Human milk nutrient fortifiers alter the developing gastrointestinal microbiota of very-low-birth-weight infants

Nutrient fortifiers are added to human milk to support the development of very-low-birth-weight infants. Currently, bovine-milk-based fortifiers (BMBFs) are predominantly administered, with increasing interest in adopting human-milk-based fortifiers (HMBFs). Although beneficial for growth, their effects on the gastrointestinal microbiota are unclear. This triple-blind, randomized clinical trial (NCT02137473) tested how nutrient-enriching human milk with HMBF versus BMBF affects the gastrointestinal microbiota of infants born < 1,250 g during hospitalization. HMBF-fed infants (n = 63, n = 269 stools) showed lower microbial diversity, altered microbial community structure, and changes in predicted microbial functions compared with BMBF-fed infants (n = 56, n = 239 stools). HMBF-fed infants had higher relative and normalized abundances of unclassified Enterobacteriaceae and lower abundances of Clostridium sensu stricto. Post hoc analyses identified dose-dependent relationships between individual feed components (volumes of mother's milk, donor milk, and fortifiers) and the microbiota. These results highlight how nutrient fortifiers impact the microbiota of very-low-birth-weight infants during a critical developmental window.

Powdered to Liquid Human Milk Fortifiers in the Preterm Infant

In preterm infants, the goal of aggressive extrauterine nutritional management is to mimic in utero growth and nutrient accretion. Over the latter half of the 20th century, nutritional optimization through the practice of fortifying human milk rose to practice with increased survival rates in preterm infants of younger gestational age. The quest for optimal preterm fortification and nutrition remains a contentious area of debate. This review aims to summarize the historical perspectives of human milk fortification as well as the current literature advocating for the use of liquid human milk fortifiers in enterally fed premature infants.

Fortification With Bovine Colostrum Enhances Antibacterial Activity of Human Milk

Objectives

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 mature bovine milk (BMFs) are routinely used for preterm infants despite risks of causing gut dysfunction and systemic infection. Gently‐processed bovine colostrum as a fortifier (BCF) may better protect against infection and inflammation. We hypothesized that BCF‐fortified HM has enhanced antimicrobial activity against pathogens that commonly cause neonatal sepsis, relative to BMF‐fortified HM.

Methods

Holder‐pasteurized HM samples (10 mothers) 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 against Staphylococcus epidermidis, Escherichia coli, and Enterococcus faecalis.

Results

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, with no difference between preterm and term HM. Addition of BMF abolished the antimicrobial effect of HM against S epidermidis and E faecalis but not E coli. By contrast, 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

BMF fortification decreased whereas BCF fortification enhanced in vitro antimicrobial activity of HM. This effect may partly be derived from the high levels of antimicrobial factors found in BCF, including lactoferrin. BCF may be a better fortifier than BMF for preterm infants.

Review concludes that specific recommendations are needed to harmonise the provision of fresh mother's milk to their preterm infants

AIM

There are no specific recommendations for using a mother's fresh milk for her preterm infant. We reviewed the available evidence on its collection, storage and administration.

METHODS

The working group of the French Neonatal Society on fresh human milk use in preterm infants searched the MEDLINE database and Cochrane Library up to June 2017 for papers published in English or French. They specifically analysed 282 papers providing information on prospective, retrospective and clinical studies and examined guidelines from various countries.

RESULTS

The review concluded that fresh mother's own milk should be favoured in accordance with the latest recommendations. However, it must be carried out under stringent conditions so that the expected benefits are not offset by risks related to different practices. The working group has summarised the best conditions for feeding preterm infants with human milk, balancing high nutritional and immunological quality with adequate virological and bacteriological safety. Professionals must provide parents with the necessary conditions to establish breastfeeding, together with specific and strong support.

CONCLUSION

Based on their review, the working group has made specific recommendations for using fresh mother's own milk under careful conditions, so that the expected benefits are not offset by risks related to practices.

ABM Clinical Protocol #29: Iron, Zinc, and Vitamin D Supplementation During Breastfeeding

A central goal of The Academy of Breastfeeding Medicine is the development of clinical protocols, free from commercial interest or influence, for managing common medical problems that may impact breastfeeding success. These protocols serve only as guidelines for the care of breastfeeding mothers and infants and do not delineate an exclusive course of treatment or serve as standards of medical care. Variations in treatment may be appropriate according to the needs of an individual patient.

Optimizing Nutrition in Preterm Low Birth Weight Infants-Consensus Summary

Preterm birth survivors are at a higher risk of growth and developmental disabilities compared to their term counterparts. Development of strategies to lower the complications of preterm birth forms the rising need of the hour. Appropriate nutrition is essential for the growth and development of preterm infants. Early administration of optimal nutrition to preterm birth survivors lowers the risk of adverse health outcomes and improves cognition in adulthood. A group of neonatologists, pediatricians, and nutrition experts convened to discuss and frame evidence-based recommendations for optimizing nutrition in preterm low birth weight (LBW) infants. The following were the primary recommendations of the panel: (1) enteral feeding is safe and may be preferred to parenteral nutrition due to the complications associated with the latter; however, parenteral nutrition may be a useful adjunct to enteral feeding in some critical cases; (2) early, fast, or continuous enteral feeding yields better outcomes compared to late, slow, or intermittent feeding, respectively; (3) routine use of nasogastric tubes is not advisable; (4) preterm infants can be fed while on ventilator or continuous positive airway pressure; (5) routine evaluation of gastric residuals and abdominal girth should be avoided; (6) expressed breast milk (EBM) is the first choice for feeding preterm infants due to its beneficial effects on cardiovascular, neurological, bone health, and growth outcomes; the second choice is donor pasteurized human milk; (7) EBM or donor milk may be fortified with human milk fortifiers, without increasing the osmolality of the milk, to meet the high protein requirements of preterm infants; (8) standard fortification is effective and safe but does not fulfill the high protein needs; (9) use of targeted and adjustable fortification, where possible, helps provide optimal nutrition; (10) optimizing weight gain in preterm infants prevents long-term cardiovascular complications; (11) checking for optimal weight and sucking/swallowing ability is essential prior to discharge of preterm infants; and (12) appropriate counseling and regular follow-up and monitoring after discharge will help achieve better long-term health outcomes. This consensus summary serves as a useful guide to clinicians in addressing the challenges and providing optimal nutrition to preterm LBW infants.

Comparison of a Powdered, Acidified Liquid, and Non-Acidified Liquid Human Milk Fortifier on Clinical Outcomes in Premature Infants

We previously compared infant outcomes between a powdered human milk fortifier (P-HMF) vs. acidified liquid HMF (AL-HMF). A non-acidified liquid HMF (NAL-HMF) is now commercially available. The purpose of this study is to compare growth and outcomes of premature infants receiving P-HMF, AL-HMF or NAL-HMF. An Institutional Review Board (IRB) approved retrospective chart review compared infant outcomes (born < 2000 g) who received one of three HMF. Growth, enteral nutrition, laboratory and demographic data were compared. 120 infants were included (P-HMF = 46, AL-HMF = 23, NAL-HMF = 51). AL-HMF infants grew slower in g/day (median 23.66 vs. P-HMF 31.27, NAL-HMF 31.74 (p < 0.05)) and in g/kg/day, median 10.59 vs. 15.37, 14.03 (p < 0.0001). AL-HMF vs. NAL-HMF infants were smaller at 36 weeks gestational age (median 2046 vs. 2404 g, p < 0.05). However AL-HMF infants received more daily calories (p = 0.21) and protein (p < 0.0001), mean 129 cal/kg, 4.2 g protein/kg vs. P-HMF 117 cal/kg, 3.7 g protein/kg , NAL-HMF 120 cal/kg, 4.0 g protein/kg. AL-HMF infants exhibited lower carbon dioxide levels after day of life 14 and 30 (p < 0.0001, p = 0.0038). Three AL-HMF infants (13%) developed necrotizing enterocolitis (NEC) vs. no infants in the remaining groups (p = 0.0056). A NAL-HMF is the most optimal choice for premature human milk-fed infants in a high acuity neonatal intensive care unit (NICU).

Human Milk Warming Temperatures Using a Simulation of Currently Available Storage and Warming Methods

Human milk handling guidelines are very demanding, based upon solid scientific evidence that handling methods can make a real difference in infant health and nutrition. Indeed, properly stored milk maintains many of its unique qualities and continues to be the second and third best infant feeding alternatives, much superior to artificial feeding. Container type and shape, mode of steering, amount of air exposure and storage temperature may adversely affect milk stability and composition. Heating above physiological temperatures significantly impacts nutritional and immunological properties of milk. In spite of this knowledge, there are no strict guidelines regarding milk warming. Human milk is often heated in electrical-based bottle warmers that can exceed 80°C, a temperature at which many beneficial human milk properties disappear. High temperatures can also induce fat profile variations as compared with fresh human milk. In this manuscript we estimate the amount of damage due to overheating during warming using a heat flow simulation of a regular water based bottle warmer. To do so, we carried out a series of warming simulations which provided us with dynamic temperature fields within bottled milk. We simulated the use of a hot water-bath at 80°C to heat bottled refrigerated milk (60 ml and 178 ml) to demonstrate that large milk portions are overheated (above 40°C). It seems that the contemporary storage method (upright feeding tool, i.e. bottle) and bottle warming device, are not optimize to preserve the unique properties of human milk. Health workers and parents should be aware of this problem especially when it relates to sick neonates and preemies that cannot be directly fed at the breast.

Antimicrobial protein and Peptide concentrations and activity in human breast milk consumed by preterm infants at risk of late-onset neonatal sepsis

Objective

We investigated the levels and antimicrobial activity of antimicrobial proteins and peptides (AMPs) in breast milk consumed by preterm infants, and whether deficiencies of these factors were associated with late-onset neonatal sepsis (LOS), a bacterial infection that frequently occurs in preterm infants in the neonatal period.

Study design

Breast milk from mothers of preterm infants (≤32 weeks gestation) was collected on days 7 (n = 88) and 21 (n = 77) postpartum. Concentrations of lactoferrin, LL-37, beta-defensins 1 and 2, and alpha-defensin 5 were measured by enzyme-linked immunosorbent assay. The antimicrobial activity of breast milk samples against Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, and Streptococcus agalactiae was compared to the activity of infant formula, alone or supplemented with physiological levels of AMPs. Samples of breast milk fed to infants with and without subsequent LOS were compared for levels of AMPs and inhibition of bacterial growth.

Results

Levels of most AMPs and antibacterial activity in preterm breast milk were higher at day 7 than at day 21. Lactoferrin was the only AMP that limited pathogen growth >50% when added to formula at a concentration equivalent to that present in breast milk. Levels of AMPs were similar in the breast milk fed to infants with and without LOS, however, infants who developed LOS consumed significantly less breast milk and lower doses of milk AMPs than those who were free from LOS.

Conclusions

The concentrations of lactoferrin and defensins in preterm breast milk have antimicrobial activity against common neonatal pathogens.

Optimizing nutrition in preterm infants

Extrauterine growth restriction is common in very preterm infants. The incidence in very-low-birth-weight infants ranges between 43% and 97% in various centers, with a wide variability due to the use of different reference growth charts and nonstandard nutritional strategies. Extrauterine growth restriction is associated with an increased risk of poor neurodevelopmental outcome. Inadequate postnatal nutrition is an important factor contributing to growth failure, as most very preterm infants experience major protein and energy deficits during neonatal intensive care unit hospitalization. First-week protein and energy intake are associated with 18-month developmental outcomes in very preterm infants. Early aggressive nutrition, including parenteral and enteral, is well tolerated in the very preterm infant and is effective in improving growth. Continued provision of appropriate nutrition (fortified human milk or premature formula) is important throughout the growing care during the hospitalization. After discharge, exclusively breast-fed infants require additional supplementation. If formula-fed, nutrient-enriched postdischarge formula should be continued for approximately 9 months corrected age. Supplementation of the preterm formulas with protein would increase the protein/energy ratio (3 g/100 kcal), leading to increased lean mass with relatively decreased fat deposition. Further research is required to optimize the nutritional needs of preterm infants and to evaluate the effects of nutritional interventions on long-term growth, neurodevelopment, and other health outcomes.

Effects of human milk fortifier with iron on the bacteriostatic properties of breast milk

OBJECTIVE

To compare bacterial growth in pure colostrum versus colostrum with human milk fortifier (HMF) containing iron.

METHODS

The growth of Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa in 78 samples of pure colostrum or colostrum with added iron-containing HMF was compared. For qualitative analysis, filter paper discs were immersed in samples from each group and incubated for 48 hours with 10(1) colony forming units (CFUs)/mL of each strain. For quantitative assessment, 1 mL of each strain containing 10(7) CFUs/mL was homogenized with 1 mL of either colostrum or colostrum with human milk fortifier, seeded into a Petri dish, and incubated at 37°C. Twenty-four hours later, the number of CFUs was counted.

RESULTS

The qualitative analysis showed no difference in bacterial growth. In the quantitative evaluation, E. coli growth in the control group was 29.4±9.7×10(6)CFU/mL, while in the HMF group it was 31.2±10.8×10(6)CFU/mL. The difference between the average growth was 1.9±4.9×10(6)CFU/mL (p=0.001). There were no differences in S. aureus and P. aeruginosa growth.

CONCLUSION

Addition of iron at this concentration reduces breast milk bacteriostatic action against E. coli.

Recurrent late-onset group B Streptococcus sepsis in a preterm infant acquired by expressed breastmilk transmission: a case report

Group B Streptococcus is a known cause of neonatal sepsis, being more common in the early period by maternal genital tract transmission and less so in the late neonatal period, ascribed to intestinal colonization or horizontal transmission. Although breastmilk transmission of Group B Streptococcus has rarely been reported in the past, most cases are of patients nursed on the mother's breast and less commonly in expressed breastmilk-fed infants. This case describes a preterm infant (born at a gestational age of 24 weeks 6 days) in the neonatal intensive care unit who acquired recurrent late-onset sepsis with Group B Streptococcus with the mother's expressed breastmilk culture growing the same organism that was later matched to the infant's isolate. The mother had presented with features of mastitis only during the second episode of sepsis and was then treated with oral antibiotics. The infant was fed on formula feeds after the second incidence and remained healthy, being discharged on a regular follow-up plan at 39 weeks corrected gestational age.

Cronobacter (Enterobacter sakazakii): an opportunistic foodborne pathogen

Cronobacter spp. (Enterobacter sakazakii) are a recently described genus that is comprised of six genomospecies. The classification of these organisms was revised based on a detailed polyphasic taxonomic study. Cronobacter spp. are regarded as ubiquitous organisms having been isolated from a wide variety of foods. These bacteria are opportunistic pathogens and are linked with life-threatening infections in neonates. Clinical symptoms of Cronobacter infection include necrotizing enterocolitis, bacteremia, and meningitis, with case fatality rates of 50-80% being reported. Contaminated powdered infant formula has been epidemiologically linked with infections. Recently, infections among immunocompromised adults, mainly the elderly, have also been reported. A high tolerance to osmotic stress and elevated temperatures contribute to the survival of Cronobacter spp. in dried foods such as powdered infant formula. Controlling the organism in the production environment, thereby reducing dissemination, necessitates the provision of suitable diagnostic tools. Studies demonstrated that a high degree of variability exists amongst the phenotypic-based methods used to identify Cronobacter spp. However, advances in molecular detection and subtyping techniques have significantly improved the identification and characterization of Cronobacter spp. The dose required to induce infection has yet to be determined. In vitro virulence studies have shown that Cronobacter spp. may survive in macrophage cells and efficiently attach to and invade epithelial cell lines. The production of exopolysaccharide may contribute to the formation of biofilm and active efflux pumps promote resistance to antimicrobial agents such as bile salts and disinfectants. A holistic approach combining techniques such as comparative genome analysis, proteomics, and in vivo challenges could help unravel the complex interactions between this pathogen and its host. These data would help identify those properties in Cronobacter spp. which enable the bacterium to survive in the production environment and infect vulnerable neonates via the food chain.

Effects of a human milk-derived human milk fortifier on the antibacterial actions of human milk

OBJECTIVES

To compare the effects of a human breastmilk-derived fortifier on the antibacterial activity of milk obtained from lactating mothers delivering prematurely with the effects of a powdered fortifier on the same milk.

STUDY DESIGN

Human milk samples were obtained after the first week of postnatal life from 10 lactating mothers, who had delivered prematurely. A bovine milk-based powdered fortifier and a human breastmilk-based frozen fortifier were evaluated. All mothers were healthy and they were not on any medications, although they were taking prenatal vitamins during lactation. The effects of each fortifier on the antimicrobial activity of milk toward Enterobacter sakazaki (ES), Escherichia coli, Clostridium difficile (CD), and Shigella soneii (SS) were evaluated by both the filter paper method and the growth inhibition method.

RESULTS

Human milk inhibited the growth of all of the test organisms. This antibacterial activity was almost totally inhibited by the addition of the bovine protein-based human milk fortifier, while it remained unaffected by the addition of the human breastmilk-based fortifier.

CONCLUSIONS

Breastmilk from women who have delivered preterm has antibacterial activity that can be affected by the addition of bovine-based fortifier, but not by the addition of a human breastmilk-based fortifier.

Effects of human milk fortifier on the antimicrobial properties of human milk

OBJECTIVE

To evaluate the effects of addition of human milk (HM) fortifier and iron on the anti-infective properties of HM.

STUDY DESIGN

HM samples were collected from 28 lactating mothers who delivered prematurely, within the first week of post-natal life. HM fortifier Eoprotin was used. The effects of this fortifier against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans were evaluated using a filter paper method. The measurements were repeated with pure HM, fortified HM and iron-added HM.

RESULTS

HM inhibited the growth of S. aureus, E. coli, P. aeruginosa and Candida. Addition of HM fortifier did not result in any significant difference on this effect. The addition of iron to HM reduced antimicrobial effect against all three bacteria and the Candida.

CONCLUSION

Premature HM has strong antimicrobial activity and addition of the milk fortifier Eoprotin does not change this effect, but addition of iron reduces this antimicrobial activity.

Neonatal group B streptococcal infection related to breast milk

Group B streptococcus is currently the most common cause of sepsis and meningitis in newborns. How should mothers whose breast milk cultures show growth of this microorganism be managed regarding breastfeeding? This case study discusses the possible transfer of group B streptococcus to a preterm infant from mother's milk. It also describes the process that was taken to preserve the breastfeeding experience while the infant was treated. The questions provoked during this investigation prompted the authors to revise procedures in their special care nursery for dealing with infants and mothers presenting with signs of infection. In this case, providing treatment for the mother and infant and withholding breast milk from the infant until cultures were negative, while supporting the mother's milk supply, made it possible for this mother to continue to breastfeed.

Effect of human milk fortifiers on bacterial growth in human milk

BACKGROUND

As a component in human milk fortifiers (HMF), iron may equilibrate with human milk for as long as 24 hours, bind important bacteriostatic proteins, and potentially affect the host defense properties of human milk.

OBJECTIVE

We compared bacterial growth in human milk prepared with each of two HMF differing in their content of iron.

STUDY DESIGN

Samples of human milk obtained from mothers of premature infants were divided and mixed with one of two HMF and maintained at refrigerator temperature. Refrigerated milk samples were removed at 0, 24, and 72 hours for determination of total bacterial colony counts (TBCC).

RESULTS

TBCC did not differ between groups but declined from 0 to 72 hours, p<0.001.

CONCLUSION

These data suggest that differences in iron content, or other nutrients in HMF, do not affect bacterial growth in human milk. Storage of fortified human milk at refrigerator temperature for 72 hours results in decreased bacterial growth. As a component in human milk fortifiers (HMF), iron may equilibrate with human milk for as long as 24 hours, bind important bacteriostatic proteins, and potentially affect the host defense properties of human milk. We compared bacterial growth in human milk prepared with each of two HMF differing in their content of iron. Samples of human milk obtained from mothers of premature infants were divided and mixed with one of two HMF and maintained at refrigerator temperature. Refrigerated milk samples were removed at 0, 24, and 72 hours for determination of total bacterial colony counts (TBCC).

Fortifying Fresh Human Milk with Commercial Powdered Human Milk Fortifiers Does Not Affect Bacterial Growth During 6 Hours at Room Temperature

OBJECTIVE

To evaluate the growth of resident aerobic mesophilic flora and added Enterobacter sakazakii in fresh, unfortified human milk; fresh human milk fortified with two commercial powdered fortifiers differing in iron content; and infant formula prepared from powder.

SUBJECTS

Eight mothers provided preterm breast milk samples.

METHODS

Breast milk samples were divided into three aliquots: unfortified, fortified with fortifier containing 1.44 mg iron/14 kcal, and fortified with fortifier containing 0.4 mg iron/14 kcal. Aliquots of formula were prepared. Breast milk and formula aliquots were divided into two test samples. Half were inoculated with low amounts of E sakazakii; half were not. All test samples were maintained at room temperature (22 degrees C), serially diluted, and plated onto agars after 0, 2, 4, and 6 hours. Plates were incubated at 35 degrees C and enumerated.

STATISTICAL ANALYSES

Data were analyzed using repeated measures analysis of variance. P<.05 was considered significant.

RESULTS

There were no differences in colony counts of aerobic bacteria among uninoculated or among inoculated human milk samples at any time; counts did not increase significantly over 6 hours. There were no differences in colony counts of E sakazakii among inoculated human milk samples at any time; counts did not increase significantly over 6 hours. Aerobic bacteria and E sakazakii colony counts from infant formula did not increase significantly over 6 hours.

CONCLUSIONS

During 6 hours at 22 degrees C, fresh human milk and formula had negligible bacterial growth; fortifying human milk with powdered fortifiers did not affect bacterial growth.

Growth, efficacy, and safety of feeding an iron-fortified human milk fortifier

OBJECTIVE

Survival rates for preterm infants who weigh between 501 and 1500 g at birth have continued to improve over time. In response to this continuing decrease in birth weight of surviving preterm infants, Enfamil Human Milk Fortifier has recently been reformulated to meet the nutritional requirements of these smaller, more rapidly growing infants. It now provides an increased protein level of 1.1 g/58 kJ, a decreased carbohydrate level of 0.2 g/58 kJ, and a combined linoleic and alpha-linolenic fatty acid content of 157 mg/58 kJ. As these very small preterm infants have an increased requirement for dietary iron, the fortifier has been supplemented with 1.44 mg/58 kJ of iron, an amount of iron similar to that provided in a typical iron-fortified term infant formula. An iron-fortified product obviates the need for administration of an iron supplement, a hyperosmolar-inducing intervention. The purpose of this prospective, double-blind, randomized, controlled study was to evaluate growth, safety, and efficacy in a population of very low birth weight (VLBW) preterm infants who received human milk fortified with either the reformulated iron-fortified powdered human milk fortifier test product (HMF-T) or a powdered commercially available human milk fortifier control product (HMF-C).

METHODS

Infants who weighed < or =1500 g, had a gestational age < or =33 weeks postmenstrual age, and had an enteral intake of at least 100 mL/kg per day of unfortified human milk were stratified by gender and birth weight and randomized to receive HMF-T or HMF-C product from study day 1 to study day 28, hospital discharge, or the termination of human milk feedings, whichever came first. Unless medically indicated, investigators were not to administer iron supplements from study days 1 to 14. Infants were assessed serially for growth; enteral and parenteral intake; serum chemistry and hematologic values; clinical histories, including the administration of blood transfusions; feeding tolerance; respiratory outcomes; and morbidities, including adverse events.

RESULTS

Of the 181 participating infants in this study, 96 received HMF-T and 85 received HMF-C. At randomization, there were no significant differences in infant characteristics between the fortifier groups. The percentage of participants who remained in the study for 28 days was similar between fortifier groups (57% HMF-T, 46% HMF-C). For both fortifier groups, the most frequent reasons for discontinuing the study before study day 28 were unavailability of human milk and hospital discharge. Rate of weight gain was similar between the fortifier groups (17.5 +/- 0.53 g/kg per day for HMF-T and 17.3 +/- 0.59 g/kg per day for HMF-C). Mean achieved weight, length, and head circumference were comparable between groups across the 28-day study period. Total protein intake from enteral and parenteral nutrition was significantly greater for the HMF-T fortifier group; however, this difference did not result in any difference in growth between the 2 fortifier groups. An analysis of the growth and energy intake data of a subset of the intent-to-treat population who adhered more strictly to the study feeding protocol yielded results similar to those seen for the intent-to-treat population. There were no clinically significant differences in the results of laboratory studies between the groups at study days 0, 14, and 28. Anemia of prematurity was prevalent in both study groups; by study day 28, median hematocrit levels were 27.0% (interquartile range [IQR]: 24.0%-29.6%) for the HMF-T group and 26.0% (IQR: 24.0%-31.0%) for the HMF-C group. Median ferritin levels were 77.0 ng/mL (IQR: 37-155 ng/ml) for HMF-T and 92.0 ng/mL (IQR: 33-110 ng/mL) for HMF-C. There were no significant differences between the study fortifier groups in regard to the receipt of medically indicated iron supplements on or before study day 14 or in the administration of blood transfusions before study day 0 or from study days 0 through 14. However, from study day 15 to study day 28, fewer HMF-T infants (n = 12) required a blood transfusion than did HMF-C infants (n = 20). Although the higher levels of iron in the HMF-T fortifier (1.44 mg vs 0.35 mg for HMF-C per 4 packets of powdered fortifier) did not prevent anemia per se, it did reduce the frequency of one of the most serious outcomes of anemia: the need for a blood transfusion. There was no statistically significant difference between fortifier groups in regard to feeding tolerance. Rates of suspected sepsis (26% HMF-T vs 31% HMF-C) and confirmed sepsis (5% HMF-T, 7% HMF-C) were low as were the rates of suspected necrotizing enterocolitis (NEC; 6% HMF-T and 5% HMF-C) and confirmed Bell's stage 2 or more NEC (1% HMF-T and 1% HMF-C). There were no statistically significant differences between the study fortifier groups in regard to the incidence of confirmed and suspected sepsis and NEC.

CONCLUSION

Both human milk fortifiers studied are safe, are well tolerated, and facilitate comparable good growth; however, using the iron-fortified product may reduce the need for blood transfusions in VLBW infants. The similar low rates of suspected and confirmed NEC and sepsis seen in both fortifier groups in this study refutes the premise that the inclusion of iron in fortifiers will increase the incidence of sepsis and NEC. Indeed, the incidence for NEC and sepsis for both groups in this study was lower than is reported for VLBW infants and similar to that seen for infants who are fed human milk.