The infant microbiome

The human microbiome is the collective term for all the microorganisms and their genetic material, known as microbes, that live and thrive upon and within our bodies. This includes bacteria, viruses, fungi, archaea and protozoa. Trillions of microbes are encompassed within the human microbiome, and these can be separated into subsections dependent on their location within the body. For example, ‘gut microbiomes’ refers to the microorganisms (and their genes) that reside in our gastro-intestinal system (The Human Microbiome Project Consortium, 2012; Prescott, 2017). The terms microbiota and microbiome are often used synonymously. However, there is a difference, as the microbiome definition refers to microorganisms and their genetic material, whereas the microbiota refers only to the microbes themselves. The microbiome is not exclusive to the human race, as animals, plants, soils and oceans all have their own microbiomes.

The human microbiome is an essential part of biology that supports many physiological functions and plays a major role in maintaining human health. The vertical transmission of microbiota from mothers to their infants has occurred throughout a period of millions of years, representing hundreds of thousands of host generations and untold billions of bacterial generations. The microbiome is a symbiotic ecosystem that has evolved alongside humanity and connects us to our ancestors and genetic lineage (Moeller et al, 2014).