Caused by a mutation, cystic fibrosis (CF) isn’t contagious, but one serious complication definitely is: infection with Mycobacterium abscessus, an obscure agent related to the microbe that causes tuberculosis. Between 5% and 10% of CF patients become infected, and that number is growing. The bacterium thrives in the excess of thick mucus that builds up in the airways of CF patients—sometimes with fatal results.
Until recently, scientists believed that patients picked up the microbe at random, from the soil or water—making infection a case of bad luck. But an analysis of hundreds of bacterial genomes from patients around the world, published in this week’s issue of Science, tells a different story. It suggests that the bacterium has adapted to humans and that several dangerous strains are spreading from one CF treatment center to the next, from country to country, and even between continents in a silent epidemic.
The researchers have no good explanation for this unexpected mobility, and not everyone is convinced. But other CF experts say the study shows that hospitals need to do more to reduce the infection risk for their patients. “This has huge implications for CF center isolation and cleansing protocols,” says Brian O’Sullivan of the Geisel School of Medicine at Dartmouth College.
In CF a defect in a gene for a transporter protein involved in mucus production affects many organs and tissues, but its most serious effects are often seen in the lungs. The mucus-filled lungs are prone to infections, which lead to inflammation, which leads to more mucus production, worsening the disease or even suffocating the patient. M. abscessus, rare in healthy people, is notoriously difficult to treat because it is resistant to most antibiotics, O’Sullivan says. “Even when it seems to be gone it can resurface months or years later.”
We need to rethink infection control measures within CF centers.