Episode Details

Russ Altman: Today, on The Future of Everything, the future of the microbiome. Now, the microbiome has gotten a lot of attention in the last few years.

Now, what is a microbiome? I guess we will learn more, but for the purposes of this discussion, it’s the full set of microbial organisms, chiefly bacteria, but maybe others, that live in different niches within our body. Our mouth, nasal cavity, skin folds, everywhere that has contact with the outside world.

The gut microbiome is one of those microbiomes and it’s the community of bacteria living in our digestive system, not necessarily related to disease, but as a normal part of our physiology. We have long known that there is a lot of bacteria in our digestive tract and we know, for example, that they help us digest our food. That’s what we were taught in medical school many decades ago when I was in medical school.

We also know that when we treat infections with antibiotics, it can alter these species because these species are sitting in your gut and they also can be very susceptible to antibiotics. So when I treat a patient for urinary tract infection or for pneumonia, not only am I killing the bacteria, hopefully, that’s causing the infection, but I’m probably altering the microbiome of that patient in ways that might lead to some symptoms. They might have some digestive issues that are associated with that antibiotic.

Now, it’s become clear that the bacteria living in our gut have much more complicated relationship with our health and with our disease. They seem to be involved in our immune system. They seem to be changing sometimes in both acute and chronic disease. The idea has even emerged that there’s a healthy microbiome, the set of bacteria that you would love to have and host in your bowel and that there might be treatments for some diseases that involve changing the microbiome to get it to be more healthy, so to speak. This has gotten probably the most publicity in the idea of fecal transplants. Yes, if you’re not familiar with that, you heard correctly. This is the idea where poop, forgive the terminology, the technical terminology, poop from healthy people is introduced into the digestive tract of people with disease in order to help them normalize their microbiome to hopefully get it back into a healthy state. So this is getting serious.

Ami Bhatt is a Professor of Medicine and Genetics at Stanford University. She has a medical specialty of hematology and studies the human microbiome, mostly in the gut, and has developed new ways to measure the presence of bacteria in the human body and ways to interpret these for health and disease.
Ami, you specialize in hematology, the study of blood and blood diseases. How does a hematologist get interested in bacteria that live in the gut?

Ami Bhatt: So, thanks a lot for having me, Russ. It’s a pleasure to be here. I actually first became interested in the bacteria viruses and fungi that live in and on us, as I think many young people did which was by watching a TV show. I remember being about, I don’t know, nine or ten years old, and I was left at home for the first time, for like ten minutes by myself or something like that, and so I turned on the TV. My younger brother and I were watching a television show about germs and, they showed these horrifying microscopic images of all of the bacteria that are squirming around everywhere. And I thought, “Wow, this is fantastic and also very gross, and we should really learn more about this.”

If you fast forward many years later, part of the reason I became interested as a hematologist and oncologist in viruses and bacteria was because I learned that viruses can cause cancers in some cases. And as you well know, there are viruses that cause well-known cancers like liver cancer. Liver cancer is caused, in some cases, by a hepatitis virus. We know that the human papilloma virus causes cervical cancer and other cancers. And I