ena-STUDY-IATA-CSIC-03-02-2017-07:34:47:274-43
Multiple approaches detect the presence of fungi in human breast milk samples.
BackgroundHuman breast milk contains a variety of bacteria, which is transmitted to the infant and contributes to microbiota development and immune maturation. The description of fungal organisms in breastmilk from healthy mothers is uncovered although the presence of fungal species has been reported in the human gut and in other mammalians’ milk.  Methods  Breast milk samples from healthy lactating mothers (n=65) within 1 month after birth were analyzed. Fungal presence was confirmed by microscopy using fungal-specific fluorescent probes (FISH), isolation in culture media and isolates identification by specific ITS and 18S PCR and Sanger-sequencing.  Total fungal load was estimated by qPCR using fungal-specific primers, and the fungal composition was determined by 28S high-throughput rDNA sequencing. In addition, milk macronutrients and human somatic cells were also quantified by spectrophotometry and cytometry. ResultsUsing different culture media, we isolated 18 strains, whose ITS and 18S rDNA genes sequencing led to confirm the presence of viable fungal species. The qPCR data showed that 89% of the samples had detectable levels of fungal DNA, at an estimated median load of 4,1x105 cells/ml in colostrum, 4,5x105 cells/ml in transition milk and 2,8x105 cells/ml in mature milk samples. Pyrosequencing of the PCR-amplified 28S rDNA gene showed that the most common genera detected were Malassezia (44%), followed by Candida (19%) and Saccharomyces (12%). Nutrient analysis of the milk samples showed significant positive correlations of Malassezia presence with lactose content, and Candida presence with protein content. We also found a significant negative correlation between Lodderomyces genus and human somatic cells, as well as positive correlations of Cladosporium and Alternaria with bacterial load. ConclusionsIn this study we have detected the presence of viable fungal species in human breast milk.  Interaction between fungi and milk’s components and bacteria present may have a relevant role for infant’s health development. However, further research should be performed to understand the origin and role of these microorganisms and their potential transmission to the developing infant.
BackgroundHuman breast milk contains a variety of bacteria, which is transmitted to the infant and contributes to microbiota development and immune maturation. The description of fungal organisms in breastmilk from healthy mothers is uncovered although the presence of fungal species has been reported in the human gut and in other mammalians’ milk.  Methods  Breast milk samples from healthy lactating mothers (n=65) within 1 month after birth were analyzed. Fungal presence was confirmed by microscopy using fungal-specific fluorescent probes (FISH), isolation in culture media and isolates identification by specific ITS and 18S PCR and Sanger-sequencing.  Total fungal load was estimated by qPCR using fungal-specific primers, and the fungal composition was determined by 28S high-throughput rDNA sequencing. In addition, milk macronutrients and human somatic cells were also quantified by spectrophotometry and cytometry. ResultsUsing different culture media, we isolated 18 strains, whose ITS and 18S rDNA genes sequencing led to confirm the presence of viable fungal species. The qPCR data showed that 89% of the samples had detectable levels of fungal DNA, at an estimated median load of 4,1x105 cells/ml in colostrum, 4,5x105 cells/ml in transition milk and 2,8x105 cells/ml in mature milk samples. Pyrosequencing of the PCR-amplified 28S rDNA gene showed that the most common genera detected were Malassezia (44%), followed by Candida (19%) and Saccharomyces (12%). Nutrient analysis of the milk samples showed significant positive correlations of Malassezia presence with lactose content, and Candida presence with protein content. We also found a significant negative correlation between Lodderomyces genus and human somatic cells, as well as positive correlations of Cladosporium and Alternaria with bacterial load. ConclusionsIn this study we have detected the presence of viable fungal species in human breast milk.  Interaction between fungi and milk’s components and bacteria present may have a relevant role for infant’s health development. However, further research should be performed to understand the origin and role of these microorganisms and their potential transmission to the developing infant.