Ingenius Bacterium Leads to Chronic Ear Infections
It has been widely reported that antibiotic resistance is on the rise. Now scientists at Nationwide Children’s Hospital have discovered an important clue about how one common bacterium seems able to elude the body’s own immune response.
Bacteria need a nutrient known as heme-iron to survive. Our bodies deprive the bacteria of this particular compound when infection is detected, sequestering heme-iron in the middle ear during the process. Amazingly, researchers have discovered that the bacterium takes refuge precisely where the compound is being “hidden,” then changes its shape to avoid detection by a roving army of white blood cells:
By devising a lab experiment that mimicked the body’s immune response to NTHI infection in the middle ear, the scientists were able to observe how the bacterium responds to this onslaught. They found that the serum that carries disease-fighting chemicals and white blood cells to the site of infection also includes heme-iron. When NTHI was re-exposed to heme-iron, it underwent structural changes that allowed it to divide much more slowly and become elongated and spaghetti-like in appearance. Because white blood cells typically target the rapidly dividing shorter cells, they ignored NTHI, leaving the bacterium to grow and thrive.
This is an elegant natural solution to a difficult puzzle, especially for an organism that cannot think. But it is yet more evidence that we have a formidable challenge ahead of us in finding new ways to defeat fast-adapting bacterial strains.