The Gut Microbiome: An 80-Year Exploration

By Kate Anastas
Friday, September 10, 2021

Key milestones have shaped our knowledge of the gut microbiota and its role in human health.

1944: Pioneering microbial ecologist Robert. E. Hungate used a revolutionary roll-tube approach to successfully culture an anaerobe, leading to the first isolation of human-associated anaerobes.

1950s: Researchers discovered that a fecal enema could successfully treat pseudomembranous enterocolitis, an inflammation of the large intestine due to an overgrowth of C. difficile.

1965: The transfer of bacterial cultures to germ-free mice paved the way for research on the effects of the gut microbiota on the host.

1970s: Studies confirmed the role of the microbiota in drug metabolism, highlighting the implications for drug inactivation, toxicity and efficacy.

1980s: Three studies provided quantitative measurements of specific bacterial taxa in early life, showing how feeding shapes an individual’s initial microbiota.

1996: A study analyzed the diversity of cultivated and noncultivated bacteria within a human fecal sample using 16S ribosomal RNA sequencing. Sequencing of 16S rRNA has become a powerful tool for assessing microbial diversity.

2000s: Researchers investigated how the immune system senses microbiota and how bacteria modulate immune system development. Scientists also found that dietary changes can alter the degradative activity of colonic microbiota. Additionally, investigators explored how antibiotics impact microbiota composition and host health.

2019: Advances in computational methods (pioneered in the environmental microbiology field) enable the reconstruction of bacterial genomes from metagenomic datasets. Using this approach, scientists identified thousands of new uncultured candidate bacterial species from the gut and other parts of the body.

2020: A large international study identified 13 specific changes in DNA affecting the existence and amount of particular bacteria in the gut. This discovery may guide understanding and treatment for conditions ranging from irritable bowel syndrome to Alzheimer’s disease.

2021: Preliminary studies show evidence that poor gut health is linked to developing a more severe case of COVID-19. Researchers continue to study the role of a healthy microbiome in a strong immune system.