The protein content of the only human milk fortifier available in South Africa was increased in 2017. The Original fortifier (OF) and the Reformulated fortifier (RF) provided similar energy. This study aimed to prospectively compare in-hospital growth during the intermediate stage of nutrition support of very low birth weight (VLBW) preterm infants receiving human milk fortified with these two formulations in a tertiary South African hospital. Intake of VLBW infants receiving exclusively human milk plus one of two fortifiers (OF 0.2gprotein/g powder; RF 0.4gprotein/g powder) was calculated. Change in Z-scores (Fenton, 2013) from start to end of fortification of weight, length and head circumference (HC) for age was calculated as primary outcomes. Additionally, weight gain velocity (g/kg/d) and gain in length and HC (cm/wk) were calculated. Fifty eight infants (52% female; gestational age: 30±2wk; birth weight: 1215±187g) received OF (2016 to 2017) and 59 infants (56% female; gestational age: 29±2wk; birth weight 1202±167g) received RF (2017 to 2018) for 15 days. Protein intake of RF (3.7±0.4g/kg/d) was significantly higher (p<0.001) than of OF (3.4±0.2g/kg/d). Protein-to-energy ratio of RF (2.6±0.2) was significantly higher (p<0.001) than of OF (2.3±0.1g/100kcal). No adverse effects were noted. In both groups Z-scores of weight and length dropped; Z-scores for HC showed slight improvements. There were no significant differences between the two groups in terms of Z-scores, weight gain velocity, length gain or HC gain. Analysed human milk from preterm infants’ mothers’ protein levels was higher than published values. In-hospital growth was not statistically different between groups, even though calculated protein intake and protein-to-energy ratio were significantly higher in RF group. / Thesis (PhD (Dietetics))--University of Pretoria, 2019. / Human Nutrition / PhD (Dietetics) / Unrestricted

INTRODUÇÃO: A lactoferrina disponível no leite materno desempenha função imunológica e protege recém-nascidos de infecções por se ligar ao ferro e privá-lo de bactérias patogênicas, o que resulta em atividade bacteriostática contra organismos patogênicos ferro dependentes. A utilização de aditivo de leite materno suplementado com ferro poderia prejudicar os efeitos protetores da lactoferrina e aumentar os riscos de infecção em recém-nascidos. OBJETIVO: Comparar o crescimento bacteriano no colostro puro versus colostro com aditivo de leite materno suplementado com ferro. MÉTODO: O crescimento bacteriano de Escherichia coli, Staphylococcus aureus e Pseudomonas aeruginosa foi comparado em 78 amostras de colostro puro ou colostro com aditivo do leite humano suplementado com ferro. Para análise qualitativa, discos de papel filtro foram imergidos nas amostras de leite materno puro ou leite materno com aditivo suplementado de ferro e incubados por 48 horas em placas de Petri contendo 101 Unidades Formadoras de Colônia por ml (UFC/ml) de cada cepa de bactérias. Para a análise quantitativa, 1ml de cada cepa de bactérias contendo 107 UFC/ml foi homogeneizado com 1ml de colostro puro ou colostro com aditivo do leite humano suplementado com ferro e semeado em placa de Petri. O número de UFC/ml foi contado após 24 horas de incubação a 37oC. RESULTADOS: A análise qualitativa não mostrou diferença no crescimento bacteriano. Na avaliação quantitativa, o crescimento de Escherichia coli no colostro puro foi de 29.4 ± 9.7 x 106CFU/ml e no colostro com aditivo de leite materno suplementado de ferro foi de 31.2 ± 10.8x 106CFU/ml, com diferença na média de crescimento de 1.9 ± 4.9 x 106CFU/ml (p = 0,001). O crescimento bacteriano nas cepas de Staphylococcus aureus e Pseudomonas aeruginosa no colostro puro e no colostro com aditivo de leite materno não apresentou diferença estatística. CONCLUSÃO: O acréscimo de aditivo de leite materno suplementado com ferro nesta concentração reduziu a ação bacteriostática contra Escherichia coli / BACKGROUND: Lactoferrin in human breast milk has been shown to protect newborns from infection by binding to iron and depriving it from pathologic bacteria that need iron to proliferate. If iron-enriched fortifier is added to breast milk, it might impair the protective effect of lactoferrin and increase the risk of infection in newborns. OBJECTIVE: To compare bacterial growth in pure colostrum versus colostrum with human milk fortifier containing iron. METHODS: The growth of Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa in 78 samples of pure colostrum or of colostrum with added human milk fortifier containing iron was compared. For qualitative analysis, filter paper discs were immersed in samples from each group and incubated for 48 hours with 101Colony Forming Units/ml of each strain. For quantitative assessment, 1 ml of each strain containing 107Colony Forming Units/ml was homogenized with 1 ml of either colostrum or colostrum with human milk fortifier, seeded into a Petri dish, and incubated at 37oC. Twenty-four hours later the number of Colony Forming Units was counted. RESULTS: Qualitative analysis showed no difference in bacterial growth. In the quantitative evaluation, Escherichia coli growth in the pure colostrum group was 29.4 ± 9.7 x 106CFU/ml while in the human milk fortifier group it was 31.2 ± 10.8x 106CFU/ml; the difference between average growth was 1.9 ± 4.9 x 106CFU/ml (p = 0.001). There were no differences in Staphylococcus aureus and Pseudomonas aeruginosa growth. CONCLUSION: Addition of iron at this concentration reduced breast milk bacteriostatic action against Escherichia coli

INTRODUÇÃO: A lactoferrina disponível no leite materno desempenha função imunológica e protege recém-nascidos de infecções por se ligar ao ferro e privá-lo de bactérias patogênicas, o que resulta em atividade bacteriostática contra organismos patogênicos ferro dependentes. A utilização de aditivo de leite materno suplementado com ferro poderia prejudicar os efeitos protetores da lactoferrina e aumentar os riscos de infecção em recém-nascidos. OBJETIVO: Comparar o crescimento bacteriano no colostro puro versus colostro com aditivo de leite materno suplementado com ferro. MÉTODO: O crescimento bacteriano de Escherichia coli, Staphylococcus aureus e Pseudomonas aeruginosa foi comparado em 78 amostras de colostro puro ou colostro com aditivo do leite humano suplementado com ferro. Para análise qualitativa, discos de papel filtro foram imergidos nas amostras de leite materno puro ou leite materno com aditivo suplementado de ferro e incubados por 48 horas em placas de Petri contendo 101 Unidades Formadoras de Colônia por ml (UFC/ml) de cada cepa de bactérias. Para a análise quantitativa, 1ml de cada cepa de bactérias contendo 107 UFC/ml foi homogeneizado com 1ml de colostro puro ou colostro com aditivo do leite humano suplementado com ferro e semeado em placa de Petri. O número de UFC/ml foi contado após 24 horas de incubação a 37oC. RESULTADOS: A análise qualitativa não mostrou diferença no crescimento bacteriano. Na avaliação quantitativa, o crescimento de Escherichia coli no colostro puro foi de 29.4 ± 9.7 x 106CFU/ml e no colostro com aditivo de leite materno suplementado de ferro foi de 31.2 ± 10.8x 106CFU/ml, com diferença na média de crescimento de 1.9 ± 4.9 x 106CFU/ml (p = 0,001). O crescimento bacteriano nas cepas de Staphylococcus aureus e Pseudomonas aeruginosa no colostro puro e no colostro com aditivo de leite materno não apresentou diferença estatística. CONCLUSÃO: O acréscimo de aditivo de leite materno suplementado com ferro nesta concentração reduziu a ação bacteriostática contra Escherichia coli / BACKGROUND: Lactoferrin in human breast milk has been shown to protect newborns from infection by binding to iron and depriving it from pathologic bacteria that need iron to proliferate. If iron-enriched fortifier is added to breast milk, it might impair the protective effect of lactoferrin and increase the risk of infection in newborns. OBJECTIVE: To compare bacterial growth in pure colostrum versus colostrum with human milk fortifier containing iron. METHODS: The growth of Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa in 78 samples of pure colostrum or of colostrum with added human milk fortifier containing iron was compared. For qualitative analysis, filter paper discs were immersed in samples from each group and incubated for 48 hours with 101Colony Forming Units/ml of each strain. For quantitative assessment, 1 ml of each strain containing 107Colony Forming Units/ml was homogenized with 1 ml of either colostrum or colostrum with human milk fortifier, seeded into a Petri dish, and incubated at 37oC. Twenty-four hours later the number of Colony Forming Units was counted. RESULTS: Qualitative analysis showed no difference in bacterial growth. In the quantitative evaluation, Escherichia coli growth in the pure colostrum group was 29.4 ± 9.7 x 106CFU/ml while in the human milk fortifier group it was 31.2 ± 10.8x 106CFU/ml; the difference between average growth was 1.9 ± 4.9 x 106CFU/ml (p = 0.001). There were no differences in Staphylococcus aureus and Pseudomonas aeruginosa growth. CONCLUSION: Addition of iron at this concentration reduced breast milk bacteriostatic action against Escherichia coli