A new study helps explain how the lung acquires its microbiome, reports MedicalXpress.  

Writing in the journal mBio, researchers from the University of Michigan Medical School and VA Ann Arbor Healthcare System offer microbiome-based evidence that most of the bacteria in the lungs of healthy people got there by way of “microaspiration.”

In other words, they rode in on tiny droplets of saliva that made it from the microbe-filled mouth to the lungs. That means they avoided the movable “wall” of tissue called the epiglottis that keeps most saliva from getting into the lower respiratory tract.

By studying the DNA of these bacteria throughout the lungs of healthy volunteers, the researchers confirmed that the population of microbes in the lungs closely resembles the population found in the mouth. And by studying their distribution within the airways, the researchers could determine their most likely route of entry.

Read more at www.medicalexpress.com