Marine Microbe Could Help Clear Chronic Sinusitis

An enzyme isolated from the marine bacterium Bacillus licheniformis incorporated into a nasal spray could help relieve chronic rhinosinusitis (CRS), according to a new study.

Researchers at Newcastle University (United Kingdom) collected mucous and sinus biopsy samples from 20 different patients, isolating between two and six different species of bacteria from each individual. In the laboratory, 24 different strains were investigated, all of which produced a slimy protective biofilm made up of a mass of bacteria held in a web of extracellular DNA that bind the bacteria to each other. This clumping protects the bacteria from attack by antibiotics, making it very difficult to clear them from the sinuses.

Based on previous studies of the marine bacterium—investigated as a tool for cleaning ship hulls—the researchers found that when the bacteria want to move, they release a deoxyribonuclease enzyme, called NucB, which breaks down the external DNA, resulting in dissolution of the biofilm and release of the bacteria. When NucB was purified and added to 14 other biofilms, the researchers succeeded in quickly dissolving the slimy biofilm, exposing the bacteria and leaving them vulnerable. The study was published on February 19, 2013, in PLOS One.

“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. In the lab, NucB cleared over half of the organisms we tested,” said corresponding author Nicholas Jakubovics, PhD, of Newcastle University.

“For many people, symptoms include a blocked nose, nasal discharge, or congestion, recurrent headaches, loss of the sense of smell and facial pain,” added Mr. Mohamed Reda Elbadawey, a consultant of Otolaryngology Head and Neck Surgery at the Newcastle Hospitals NHS Foundation Trust (United Kingdom). “While steroid nasal sprays and antibiotics can help some people, for the patients I see, they have not been effective and these patients have to undergo the stress of surgery. If we can develop an alternative we could benefit thousands of patients a year.”

Persistent colonization of microbial biofilms is a major factor in the pathogenesis of CRS, with obstructive mucin biofilms detected on the mucosa in the paranasal sinuses, with or without polyps, and in the absence of other symptoms that would indicate fungal rhinosinusitis. The removal of this mucin, which is extremely tenacious, is the cornerstone of surgical treatment of CRS.

Related Links:
Newcastle University
Newcastle Hospitals NHS Foundation Trust