‘Sheer Stress’ Could Make Bacteria in Cystic Fibrosis Less Virulent
A recent study from Belgium showed that a common bacterium found in the lungs of people with cystic fibrosis (CF) might be converted to a less dangerous form, and could possibly aid in the development of treatments for the disease.
The research report, “Effect of Shear Stress on Pseudomonas aeruginosa Isolated from the Cystic Fibrosis Lung” appeared in the American Society for Microbiology’s journal mBio.
Cystic fibrosis, a serious genetic condition characterized by the formation of thick mucus in the lungs, digestive tract and other body regions, is caused by mutations in the CFTR gene.
Scientists have identified over 2,000 mutations in the CFTR gene that are associated with the disease, which normally presents in patients at birth. CFTR — the cystic fibrosis transmembrane conductance regulator — helps shuttle chloride ions in and out of cells, balancing salt and water in the cells that line the lungs.
Chronic bacterial colonies can develop in the lungs of CF patients, and the bacterium Pseudomonas aeruginosa is a common culprit.
The researchers, led by Jozef Dingemans of the Department of Bioengineering Sciences, Research Group Microbiology, Vrije Universiteit Brussel, and VIB Structural Biology, Brussels, grew the bacteria in the lab and tried to determine conditions that best promoted growth.
They found that shear stress prevented the bacterium from being as infectious and hazardous (known as biofilm mode), and it transitioned to a less growth-promoting form (planktonic). Shear stress refers to forces being applied in parallel to the surface where the bacteria grows.
Investigators noted that “our study revealed a way to modulate the behavior of a highly adapted P. aeruginosa CF strain by means of introducing shear stress, driving it from a biofilm lifestyle to a more planktonic lifestyle.”
The question then becomes, how can shear stress be applied to the lungs of people with CF? According to the study’s authors, this could be accomplished through specific types of physical therapies, or by ventilation of the lungs.
“These techniques could possibly introduce shear stress in the lungs of CF patients, thereby causing P. aeruginosa to transition from a biofilm mode of growth to a planktonic lifestyle,” they wrote.