Changes in the Bacterial Diversity of Human Milk during Late Lactation Period (Weeks 21 to 48)

Marin-Gómez, Wendy; Grande, Ma José; Pulido, Rubén Pérez; Gálvez, Antonio; Lucas, Rosario

doi:10.3390/foods9091184

Cited by 8 publications

(5 citation statements)

References 38 publications

(60 reference statements)

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“…Firmicutes significantly increased over time while Proteobacteria significantly decreased from week 4 to 24 lactation. This is in line with other studies that have reported that Firmicutes and Proteobacteria dominate in milk samples, but their proportions change considerably depending on sampling week 43 .…”

Section: Discussionsupporting

confidence: 93%

The human milk microbiome aligns with lactation stage and not birth mode

Lyons

Shea

Grimaud

et al. 2022

Sci Rep

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We analysed the human milk microbiome in a cohort of 80 lactating women and followed the dynamics in taxa over the course of lactation from birth to 6 months. Two hundred and thirty one milk samples were collected from full-term lactating women at 1, 4, 8 and 24 weeks following birth and analysed for microbiota composition using 16S rRNA sequencing. A significant decrease in milk microbiota diversity was observed throughout the first 6 months of lactation, with the greatest difference seen between week 8 and week 24. Nine genera predominated in milk over lactation from week 1 to week 24, comprising of Staphylococcus, Streptococcus, Pseudomonas, Acinetobacter, Bifidobacterium, Mesorhizobium, Brevundimonas, Flavobacterium, and Rhodococcus; however, fluctuations in these core genera were apparent over time. There was a significant effect of stage of lactation on the microbiome, while no effect of birth mode, infant sex and maternal BMI was observed throughout lactation. Streptococcus had the highest mean relative abundance at week 1 and 24 (17.3% and 24% respectively), whereas Pseudomonas predominated at week 4 (22%) and week 8 (19%). Bifidobacterium and Lactobacillus had the highest mean relative abundance at week 4 (5% and 1.4% respectively), and occurred at a relative abundance of ≤ 1% at all other time points. A decrease in milk microbiota diversity throughout lactation was also observed. This study concluded that lactation stage was the primary driving factor in milk microbiota compositional changes over lactation from birth to 6 months, while mode of delivery was not a factor driving compositional changes throughout human lactation.

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Section: Discussionsupporting

confidence: 93%

The human milk microbiome aligns with lactation stage and not birth mode

Lyons

Shea

Grimaud

et al. 2022

Sci Rep

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“…This is probably due to the inclusion of the phylum Proteobacteria , which together with the Bacteroidetes , Firmicutes , and Actinobacteria phyla represents approximately 98% of the bacterial phyla present in human milk. Similar findings have been observed by others [ 36 , 37 , 38 ]. As in the human intestine, the proportions of Firmicutes and Bacteroidetes had higher medians than the phylum Actinobacteria [ 3 , 26 ].…”

Section: Discussionsupporting

confidence: 93%

Firmicutes, Bacteroidetes and Actinobacteria in Human Milk and Maternal Adiposity

et al. 2022

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The main objective was to explore the relationship between the microbiota of human milk and adiposity in Mexican mothers during the first lactation stage. Methods: Seventy lactating women were included. Adiposity by anthropometric measurements and by bioelectric impedance was obtained. The donation of human milk was requested, from which bacterial DNA was extracted and qPCR of the 16S region was performed. The Mann–Whitney U test, Spearman and Pearson correlations, and multiple linear regressions models were also calculated. Results: The median percentage of Bacteroidetes had a direct and significant correlation with normal adiposity, current BMI, waist circumference, and body fat percentage. The correlation with current BMI became significantly inverse in women with BMI ≥ 25. In women with normal BMI, the percentage of Actinobacteria showed a direct and significant correlation with current BMI, waist circumference, and percentage of body fat. Multiple linear regressions showed that pre-pregnancy BMI was the variable with the highest predictive value with the Bacteroidetes phyla in normal BMI and in BMI ≥ 25. Conclusions: the adiposity of the woman before pregnancy and during lactation would have an important effect on the abundance of Bacteroidetes and Actinobacteria in human milk.

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“…Preparation of Bacterial Cultures and Spore Suspensions for Human Milk Inoculation. Vegetative bacterial strains (Cronobacter sakazakii, 34 Enterococcus faecium, 35 Listeria monocytogenes 36 , and Staphylococcus aureus 37 ) and spore-forming bacteria (Bacillus subtilis, Bacillus cereus, Paenibacillus macerans, and Paenibacillus polymyxa 38 ) were selected for inoculation in this study based on their potential presence in donor human milk and/or the detection of their species or genera in donor human milk as contaminants (Supplementary Table 1). All bacteria were maintained cryogenically by the Food Safety Systems Lab (Oregon State University, Corvallis, OR).…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

Optimized Ultraviolet-C Processing Inactivates Pathogenic and Spoilage-Associated Bacteria while Preserving Bioactive Proteins, Vitamins, and Lipids in Human Milk

Liang,

Mohamed,

Pung

et al. 2024

J. Agric. Food Chem.

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Holder pasteurization (HoP) enhances donor human milk microbiological safety but damages many bioactive milk proteins. Though ultraviolet-C irradiation (UV−C) can enhance safety while better preserving some milk proteins, it has not been optimized for dose or effect on a larger array of bioactive proteins. We determined the minimal UV−C parameters that provide >5log reductions of relevant bacteria in human milk and how these treatments affect an array of bioactive proteins, vitamin E, and lipid oxidation. Treatment at 6000 and 12 000 J/L of UV−C resulted in >5-log reductions of all vegetative bacteria and bacterial spores, respectively. Both dosages improved retention of immunoglobulin A (IgA), IgG, IgM, lactoferrin, cathepsin D, and elastase and activities of bile-salt-stimulated lipase and lysozyme compared with HoP. These UV−C doses caused minor reductions in αtocopherol but not γ-tocopherol and no increases in lipid oxidation products. UV−C treatment is a promising approach for donor human milk processing.

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Changes in the Bacterial Diversity of Human Milk during Late Lactation Period (Weeks 21 to 48)

Cited by 8 publications

References 38 publications

The human milk microbiome aligns with lactation stage and not birth mode

The human milk microbiome aligns with lactation stage and not birth mode

Firmicutes, Bacteroidetes and Actinobacteria in Human Milk and Maternal Adiposity

Optimized Ultraviolet-C Processing Inactivates Pathogenic and Spoilage-Associated Bacteria while Preserving Bioactive Proteins, Vitamins, and Lipids in Human Milk

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