Chronic sinusitis, which typically lasts more than 4 weeks and occurs more than 4 times a year, is one of the more prevalent chronic illnesses in the United States, affecting about 1 in 8 adults annually, resulting in almost 12 million visits to physician offices. Many types of chronic sinusitis are associated with the buildup of microbial biofilms that can make it difficult for antimicrobial drugs to reach the infecting bacteria. Microbes living under biofilms can be up to 1000-fold more resistant to antibiotics than free-living cells of the same species.
Previous studies had demonstrated that the enzyme, extracellular DNase (NucB), produced by marine-derived Bacillus licheniformis, can disperse bacterial biofilms, so the Newcastle researchers decided to see if it worked on bacteria specifically associated with chronic sinusitis. To test their hypothesis, they collected mucous and sinus biopsy samples from 20 different patients, isolating between 2 and 6 different bacterial species from each individual, and cultured 24 different strains on glass surfaces. Of these, 14 strains (58%) were disrupted by treatment with NucB.
“In effect, the enzyme breaks down the extracellular DNA, which is acting like a glue to hold the cells to the surface of the sinuses,” said Nicholas Jakubovics, PhD, a coauthor of the Newcastle study in a release. “In the lab, NucB cleared over half of the organisms we tested.”
The researchers cautioned that their findings were very preliminary. They are currently testing the safety of NucB, with a view to conducting animal and clinical trials.