The human microbiome is a vast frontier of known and unknown microscopic creatures carrying out untold biochemical transformations for metabolic pathways we have yet to map out.
Trillions of microbes—including bacteria, viruses, and fungi—interact with human physiology, outnumbering human cells. Most microbes are “friendly,” and among their functions is keeping the disease-causing pathogenic ones from creating problems. Pathogenic bugs occasionally cause acute illnesses and play a role in chronic diseases.
