A strain of good gut bacteria that has been linked to providing relief in intestinal problems, respiratory infections and some skin disorders works largely as a facilitator, by modifying the activity of other gut bacteria, research has found.

The researchers studied how Lactobacillus rhamnosus GG (LGG) can help improve health and prevent disease.

"This species of bacteria has a reputation for being really useful to humans," said Claire Fraser, professor of medicine at the University of Maryland School of Medicine.

"So we wanted to better understand how it might work in the human intestine," Fraser noted.

For the study, the researchers tested 12 participants, who ingested LGG twice a day for 28 days.

They analysed gut bacteria before and after this regimen, and found that ingesting LGG led to increases in several genes that foster several species of gut bacteria, including Bacteroides, Eubacterium, Faecalibacterium, Bifidobacterium and Streptococcus.

These microbes have been shown to have a range of benefits in humans, including the promotion of a healthy immune system.

However, Fraser noted that LGG may also have direct effects, in addition to its ability to modify the overall ecosystem.

"This is a new idea, that some probiotics may work by affecting the overall ecosystem of the gut," Fraser pointed out.

The study was published in the journal mBio.