New Method Tests for Cystic Fibrosis Infection Pathogens

A new method of testing the most common cause of life-threatening infection in people with cystic fibrosis could improve efforts to study and combat the illness.

Cystic fibrosis is a serious genetic disease that causes recurring lung infections, bacteria colonize a patient's lungs, usually beginning in childhood, leading to difficulty breathing. One of the most dangerous of these bacteria is Pseudomonas aeruginosa, which, within the unique mucus that forms in the lungs of a person with cystic fibrosis, develops into large, antibiotic-resistant colonies.

Scientists at the University of Texas (Austin, TX, USA) applied new technology to bacteria thriving in actual samples of the mucus from cystic fibrosis (CF) lungs to model the behavior of the bacterium in that environment. The team was then able to test tens of thousands of mutations of two strains of P. aeruginosa, which helped them identify key ways the pathogen behaves during an infection and the genes that might be essential for reproduction.

The new model allows scientists to run large-scale studies in conditions that are much more like the actual places where the bacteria colonize, without requiring scientists to collect countless specimens of actual mucus, called sputum, from humans. The ability to re-create conditions closer to the sputum in the lung of a CF patient will lead to better understanding of how different strains of the bacterium behave. It will also allow for easier identification of genes that contribute to the bacteria's spread from patient to patient, and more meaningful scientific trials to understand the bacteria’s resistance to antibiotics or identify new antimicrobial compounds that target specific genes necessary for maintaining these persistent infections.

John LiPuma, MD, a professor of pediatrics and epidemiology, said, “For the past decade, we have understood that Pseudomonas is arguably the major colonizing infection for people with cystic fibrosis. For a long time we have studied Pseudomonas the way we study other pathogens, but the cystic fibrosis lung is extraordinarily complex. In the scientific community, we've got to develop systems biology approaches, such as this one, that take a more sophisticated approach to get us where we need to be.” The study was published on March 16, 2015, in the journal Proceedings of the National Academy of Sciences of the United States of America (PNAS).

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