31 In the present study, term colostrum was used instead of preterm colostrum, and this might be a limitation, although lactoferrin levels between preterm and term colostrum appear not to be clearly defined. When the present results are extrapolated to clinical practice, it is important to highlight

that, although HMF is currently used for preterm infants, in Brazil a large number of preterm infants receive HMF added to human milk from the Human Milk Bank, and in that case they usually receive term milk. learn more None of the previous studies evaluated bacterial growth with the addition of the HMF used in this study, which is the only fortifier available in Brazil (0.28 mg of iron in 1 g of fortifier). It is also important to consider that in the studies by Chan et al., different bacteria

strains were analyzed: E. coli, Staphylococcus, Enterobacter sakazakii, and group B Streptococcus. In the present study, E. coli growth was higher in the samples with HMF, similarly to the studies by Chan et al. 7 and 8 The bacterial strains selected for this study are the most frequent reported by the Commission of Hospital Infection Control of the hospital where the study was performed. The correlation coefficients between C group samples Navitoclax chemical structure and HMF group samples were significant for all strains of bacteria, which Vildagliptin demonstrates that the bacterial growth was similar in all samples when the two groups were compared, indicating that bacterial growth followed the same pattern in both groups, regardless of the addition of HMF. The mechanism through which lactoferrin inhibits bacterial growth remains unclear. The bacteriostatic capacity of lactoferrin is often attributed to its ability to chelate iron, restricting this essential nutrient for pathogenic bacteria proliferation. However, it is important to highlight that studies have also shown that the bactericidal activity is not dependent on the degree of iron saturation of lactoferrin. Since lactoferrin has been shown to affect the

immune system and the mucosa immune function, the addition of iron may affect these actions. However, since the present study was in vitro, it was not possible to analyze those functions. 7, 11, 12, 13, 32 and 33 Care should be taken when extrapolating the present results to clinical practice. In vitro, it appears that the HMF currently available in Brazil may increase the risk for E. coli proliferation. However, in vivo studies are needed to test the clinical significance of these results. Contradictory results found in similar studies are probably due to different milk samples, which may vary depending on ethnic characteristics, infant age at the delivery time, milk maturity, time of sample collection, added iron amount, and strain of bacteria analyzed.