Mercury is a metal found in the Earth's crust that often gets ingested through seafood, leading to serious health issues, including damage to the nervous, digestive and immune systems, lungs and kidneys. Children exposed to mercury in the womb can have brain damage, hearing and vision problems.

Although mercury exists in various forms, methylmercury is the form that gets absorbed easily through food, causing poisoning in children and posing a threat to fetal and neurodevelopment.

"It accumulates in living things, in plants and fish. We eat those things, and it accumulates in us," said Daniela Betancurt, lead researcher of a new study about mercury poisoning.

In the latest study, researchers developed a new probiotic bacteria that can express an enzyme to convert more absorbable forms of mercury into less absorbable forms. Using metagenomic sequencing, they evaluated how humans and mice respond to mercury exposure and used the insights to develop a probiotic bacteria that can detoxify mercury.

The researchers first analyzed organomercurial lyase, an enzyme that demethylates methylmercury, making it less absorbable. They then examined the bacteria in the gut to find the type most likely to express enzymes that would convert mercury into less deadly forms.

The study revealed that a gene in the nonpathogenic bacteria Bacillus megaterium codes for organomercurial lyase. The team then inserted the gene into the probiotic bacterial strain Lacticaseibacillus.

"We inserted a gene from Bacillus megaterium a bacteria isolated from an industrial disaster in Minimata Bay Japan. The gene provides the ability to convert methylmercury to poorly absorbed forms," Betancurt told Medical News Today. "It's a perfect probiotic for this because we have previously shown it works in humans, and now we are engineering it to make it even better. It is inside the gut, it grabs the methylmercury, then it goes out."

Researchers will now conduct mice study to evaluate the effectiveness of the bacteria, and how it affects the gut when the host is orally exposed to mercury.

"We are investigating other metals as well, and [are] interested in understanding how the microbial community reacts to different metals. There is already a precedent for Lactobacilli to improve iron absorption and we hope to examine this in further detail in coming work," Betancurt added.