Urease positive bacteria caused by Breast Milk Urea

 By: Karla Hinojosa 

Figure. A) Specifies the type of urease gene clusters that are found in B. infantis. B) A software application was used to generate a phylogenetic tree that showed the urease subunit alpha genes that were expected to be located in the human stomach. C) Metagenomic urease gene hits that were retrieved from urease protein subunits. D) Ratio of reads showing the urease proteins of all the bacterial species depending on infants being breastfed or through formula. 

In infants, human milk supports the growth of a beneficial microbiome. Human milk contains urea. The study investigates whether the microbiota can utilize urea from human milk, as well as how the microbiota restores and uses nitrogen from breast milk. It is critical since infants rely on feeding and are required for health reasons. The microbiome assists infants in receiving amino acids and vitamins, as well as gut maturation and immunological development. In order to feed bacterial demands, bacterial urease can play a role in the gut nitrogen cycle. Nitrogen, particularly urea, has a significant impact on the human gut flora. In comparison to formula-fed infants, breast-fed newborns had a higher urea level. Urease-related genes were studied using an infant gut metagenome database. Urease-related hits, such as urease protein subunits, urea transporters, urease accessory proteins, and urease activity regulating genes, were filtered out of the alignment findings. Bifidobacterium longum subsp. Infantis and Bifidobacterium breve were cultivated on a special Bifidobacterium agar medium designed for counting Bifidobacterium species. A colorimetric urea assay was used to determine the urea levels. Five Bifidobacterium urease genes were discovered in seven species related to the human gut, one of which is Bifidobacterium infantis. The metagenome revealed a total of 27 taxa for urease protein components, with Bifidobacterium accounting for 9% of the total. Further research concluded that B. infantis may utilize urea as its primary nitrogen source. Urease can be used as a growth factor to use urea as the main nitrogen source. Urea in breast milk can shape a microbial potentially beneficial strain is based on the discovery that urea in breast milk can influence a microbial population. As a result, Bifidobacterium urease is an important component of the microbiota that uses urea in breastfed newborns. Bifidobacteria is essential for the well-being of infants. 

Original Article: 

Schimmel P., Kleinjans L., Bongers S. R., Knol J., Belzer C. (2021). Breast milk urea as a nitrogen source for urease positive Bifidobacterium infantis. FEMS Microbiology Ecology, Volume 97, Issue 3, fiab019, https://doi.org/10.1093/femsec/fiab019