Inhale, exhale. Humans breathe between 17,000 to 23,000 times a day, on average. But for more than 70,000 children and young adults around the world, taking a breath can be a struggle because of the rare disease cystic fibrosis. A gene that normally triggers a certain protein to move chloride, found in salt, to cell surfaces, where it can attract water, malfunctions in cystic fibrosis patients, so their mucus becomes thick and sticky. In the lungs, the thick mucus clogs airways. It also becomes a breeding ground for harmful bacteria likePseudomonas aeruginosa, a particularly nasty pathogen that can quickly lead to inflammation and life-threatening infections.