WIKIMEDIA, MARIANA RUIZ VILLARREALIf the human digestive tract were a river from the mouth extending through the stomach and intestines, ending at the anus, the lungs would be pools alongside that river that are often swept by eddying currents, according to Gary Huffnagle from the University of Michigan, who began studying the bacterial communities that inhabit these pool-like organs nearly a decade ago. “There’s a constant flow into [the] lungs of aspirated bacteria from the mouth,” he said. But through the action of cilia and the cough reflex, among other things, there’s also an outward flow of microbes, making the lung microbiome a dynamic community.
Like the placenta, urethra, and other sites of the body now known to harbor commensal bacteria, researchers and clinicians once considered the lung to be sterile in the absence of infection. Over the last 10 years, however, evidence has been building that, although it is far less-populated than the mouth or gut, the disease-free lung, too, is populated by a persistent community of bacteria. Shifts in the lung microbiome have been correlated with the development of chronic lung conditions like cystic fibrosis (CF) or chronic obstructive pulmonary disease (COPD), although the relationship between the lung microbiome and disease is complicated.
The surface area of the healthy lung is a dynamic environment. The respiratory organ is constantly bombarded by debris and microbes that make their way ...
