Asthma has long been assumed to be purely an allergic reaction. However, it turns out that bacterial infection may play an important role as well. Yvonne Huang of the University of California, San Francisco and her colleagues have found much richer and more diverse bacterial colonization in the airways of asthmatics, as opposed to healthy people.
The researchers assayed the bronchial tracts of 65 asthmatics and 10 healthy controls to look for numbers and types of bacteria. They used a tool that detects 16S ribosomal RNA (molecules that are present in all bacterial, but not human cells) to assess total numbers, and a DNA database of 8500 specimens to pick out specific species. The asthmatics not only had more total bacteria living in their respiratory tracts, but they had a much greater variety of types of bacteria.
This is interesting for two reasons. First, contrary to previous thought, our tracheas are not sterile, even in healthy people. We all have some microbiotica living in our airways. Second, and more importantly, this opens up new treatment possibilities for asthmatics. It will be interesting to see whether decreasing either the total number of bacteria or the diversity of species could alleviate symptoms.