Washington, June 18 (IANS) A single species of bacteria that lives in the gut can result in the development of arthritis, says new research.

The gut is filled with thousands of species of bacteria, many of which are helpful and aid in the development of a normal, healthy immune system.

Gut-residing bacteria can also play a role in autoimmune disorders in which the body attacks its own cells. It turns out that rheumatoid arthritis is one such disorder.

Researchers Christophe Benoist and Diane Mathis at Harvard Medical School (HMS) and Dan Littman at New York University made this discovery while working on mice prone to arthritis.

‘In the absence of bacteria, these mice didn’t develop arthritis, but the introduction of a single bacterium was enough to jump-start the immune process that leads to development of the disease,’ says Mathis, an HMS professor of pathology.

The researchers began by raising arthritis-prone mice in a germ-free environment. The mice had much lower levels of arthritis-causing auto-antibodies than mice raised in a germ-infested facility.

At three weeks of age, some mice were transferred to a germ-infested facility and the researchers introduced bacteria into their systems. After this, the animals rapidly began producing auto-antibodies and developed arthritis within four days.

The findings appear in the forthcoming June 25 issue of Immunity.