Having found a novel genetic arrangement that may help Bacteroides fragilis protect itself from tetracycline in the human gut, researchers at the Marine Biological Laboratory (MBL) and collaborators say they have discovered previously unseen genetic arrangements that confer antibiotic resistance.

The findings reported in the journal mBio involved Bacteroides fragilis recovered from a patient with ulcerative colitis. The team had a large set of samples to analyze from patients with inflammatory bowel disease that had been surgically treated to alleviate inflammation.

Ultimately, they discovered high-copy sections of the genome that contained DNA fragments that can move around in the genome or even jump into a different genome. These transposons have a high potential for exchange in the human intestines, where vast numbers of species of gut bacteria are constantly in close proximity. And it appears the rate of exchange increases when there is inflammation. Researchers further believe these transposons are a key vehicle for horizontal gene transfer.

Although the researchers do not think their findings will dramatically impact understanding of antibiotic resistance, they say it opens new avenues for study.