But the links between microbes and poor health can be more complicated. Our bodies are naturally home to tens of trillions of bacteria. Most are benign, or even beneficial. But often, these so-called microbiomes can shift into a negative state. For example, inflamed guts tend to house an unusually large number of bacteria from the Enterobacteriaceae family (pronounced En-ter-oh-back-tee-ree-ay-see-ay, and hereafter just “enteros”). There’s no villain in this scenario, no single antagonist as there would be in the case of tuberculosis or cholera. The enteros are part of a normal gut; it’s the same old community, just altered.
These kinds of shifts are harder to rectify. For a start, it’s often unclear if the enteros cause the inflammation, if the inflammation changes the microbes, or both. Even if the microbes are responsible, how do you fix that? Dietary changes are typically too imprecise. Antibiotics are too crude, killing off beneficial microbes while suppressing the problematic ones.
But Sebastian Winter, from the University of Texas Southwestern Medical Center,
has an alternative. His team showed that the blooming enteros rely on enzymes that, in turn, depend on the metal molybdenum. A related metal—tungsten—can take the place of molybdenum, and stop those enzymes from working properly.
By feeding mice small amounts of tungsten salts, Winter’s team managed to specifically prevent the growth of enteros, while leaving other microbes unaffected. Best of all, the tungsten treatment spared the enteros under normal conditions, suppressing them only in the context of an inflamed gut. It’s a far more precise and subtle way of changing the microbiome than, say, blasting it with antibiotics. It involves gentle nudges rather than killing blows.
To be clear, no one knows if this would work in people. “We can cure inflammatory bowel disease in mice, and that’s the best we can say at this point,” Winter says. “We’re far away from having a treatment. And of course, tungsten is toxic, so this is not an endorsement that people with IBD should drink tungsten-contaminated water. But we can now screen for molecules that have the same activity without the toxicity.”
