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Relationship between Milk Microbiota, Bacterial Load, Macronutrients, and Human Cells during Lactation.

Boix-Amorós A, Collado MC, Mira A - Front Microbiol (2016)

Bottom Line: Fat, protein, lactose, and dry extract of milk as well as the number of somatic cells were also analyzed.We observed that milk bacterial communities were generally complex, and showed individual-specific profiles.The median bacterial load was 10(6) bacterial cells/ml through time, higher than those numbers reported by 16S gene PCR and culture methods.

View Article: PubMed Central - PubMed

Affiliation: Department of Health and Genomics, Center for Advanced Research in Public Health, FISABIO FoundationValencia, Spain; Department of Biotechnology, Institute of Agrochemistry and Food Technology, Spanish National Research CouncilValencia, Spain.

ABSTRACT
Human breast milk is considered the optimal nutrition for infants, providing essential nutrients and a broad range of bioactive compounds, as well as its own microbiota. However, the interaction among those components and the biological role of milk microorganisms is still uncovered. Thus, our aim was to identify the relationships between milk microbiota composition, bacterial load, macronutrients, and human cells during lactation. Bacterial load was estimated in milk samples from a total of 21 healthy mothers through lactation time by bacteria-specific qPCR targeted to the single-copy gene fusA. Milk microbiome composition and diversity was estimated by 16S-pyrosequencing and the structure of these bacteria in the fluid was studied by flow cytometry, qPCR, and microscopy. Fat, protein, lactose, and dry extract of milk as well as the number of somatic cells were also analyzed. We observed that milk bacterial communities were generally complex, and showed individual-specific profiles. Milk microbiota was dominated by Staphylococcus, Pseudomonas, Streptococcus, and Acinetobacter. Staphylococcus aureus was not detected in any of these samples from healthy mothers. There was high variability in composition and number of bacteria per milliliter among mothers and in some cases even within mothers at different time points. The median bacterial load was 10(6) bacterial cells/ml through time, higher than those numbers reported by 16S gene PCR and culture methods. Furthermore, milk bacteria were present in a free-living, "planktonic" state, but also in equal proportion associated to human immune cells. There was no correlation between bacterial load and the amount of immune cells in milk, strengthening the idea that milk bacteria are not sensed as an infection by the immune system.

No MeSH data available.


Related in: MedlinePlus

Richness and diversity of milk samples. (A) Shows the richness in the samples as inferred by computation of Chao1 index, compared with bacterial load in cells per ml, as estimated by qPCR. (B) Shows the diversity in the samples as inferred by Shannon index, compared with bacterial load. (n = 30 in both cases).
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Figure 6: Richness and diversity of milk samples. (A) Shows the richness in the samples as inferred by computation of Chao1 index, compared with bacterial load in cells per ml, as estimated by qPCR. (B) Shows the diversity in the samples as inferred by Shannon index, compared with bacterial load. (n = 30 in both cases).

Mentions: Additionally, we analyzed the diversity and richness of the bacteria present in these samples by the statistic indexes “Shannon” and “Chao1,” respectively. Neither diversity nor richness increased or decreased significantly with bacterial load (Figure 6). This also supports a lack of subclinical or sub-acute mastitis, as an increase of a few dominant bacteria would be expected in case of infection, and suggests that milk microbiota is not activating an immune response in the host, although inflammatory markers have not been measured.


Relationship between Milk Microbiota, Bacterial Load, Macronutrients, and Human Cells during Lactation.

Boix-Amorós A, Collado MC, Mira A - Front Microbiol (2016)

Richness and diversity of milk samples. (A) Shows the richness in the samples as inferred by computation of Chao1 index, compared with bacterial load in cells per ml, as estimated by qPCR. (B) Shows the diversity in the samples as inferred by Shannon index, compared with bacterial load. (n = 30 in both cases).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4837678&req=5

Figure 6: Richness and diversity of milk samples. (A) Shows the richness in the samples as inferred by computation of Chao1 index, compared with bacterial load in cells per ml, as estimated by qPCR. (B) Shows the diversity in the samples as inferred by Shannon index, compared with bacterial load. (n = 30 in both cases).
Mentions: Additionally, we analyzed the diversity and richness of the bacteria present in these samples by the statistic indexes “Shannon” and “Chao1,” respectively. Neither diversity nor richness increased or decreased significantly with bacterial load (Figure 6). This also supports a lack of subclinical or sub-acute mastitis, as an increase of a few dominant bacteria would be expected in case of infection, and suggests that milk microbiota is not activating an immune response in the host, although inflammatory markers have not been measured.

Bottom Line: Fat, protein, lactose, and dry extract of milk as well as the number of somatic cells were also analyzed.We observed that milk bacterial communities were generally complex, and showed individual-specific profiles.The median bacterial load was 10(6) bacterial cells/ml through time, higher than those numbers reported by 16S gene PCR and culture methods.

View Article: PubMed Central - PubMed

Affiliation: Department of Health and Genomics, Center for Advanced Research in Public Health, FISABIO FoundationValencia, Spain; Department of Biotechnology, Institute of Agrochemistry and Food Technology, Spanish National Research CouncilValencia, Spain.

ABSTRACT
Human breast milk is considered the optimal nutrition for infants, providing essential nutrients and a broad range of bioactive compounds, as well as its own microbiota. However, the interaction among those components and the biological role of milk microorganisms is still uncovered. Thus, our aim was to identify the relationships between milk microbiota composition, bacterial load, macronutrients, and human cells during lactation. Bacterial load was estimated in milk samples from a total of 21 healthy mothers through lactation time by bacteria-specific qPCR targeted to the single-copy gene fusA. Milk microbiome composition and diversity was estimated by 16S-pyrosequencing and the structure of these bacteria in the fluid was studied by flow cytometry, qPCR, and microscopy. Fat, protein, lactose, and dry extract of milk as well as the number of somatic cells were also analyzed. We observed that milk bacterial communities were generally complex, and showed individual-specific profiles. Milk microbiota was dominated by Staphylococcus, Pseudomonas, Streptococcus, and Acinetobacter. Staphylococcus aureus was not detected in any of these samples from healthy mothers. There was high variability in composition and number of bacteria per milliliter among mothers and in some cases even within mothers at different time points. The median bacterial load was 10(6) bacterial cells/ml through time, higher than those numbers reported by 16S gene PCR and culture methods. Furthermore, milk bacteria were present in a free-living, "planktonic" state, but also in equal proportion associated to human immune cells. There was no correlation between bacterial load and the amount of immune cells in milk, strengthening the idea that milk bacteria are not sensed as an infection by the immune system.

No MeSH data available.


Related in: MedlinePlus