What a chronic ear infection looks like

These are images from the inside of two human ears. The ear on the top doesn't get chronic infections. The ear on the bottom does. The difference seems to be the presence of a biofilm—a little colony of bacteria or other microorganisms that build up in a thin layer.
Biofilms happen all over the place in nature. That slime that covers the surface of rocks at the bottom of a river or lake? That's a biofilm. The slick, green coating on the underside of a boat when you pull it out of the water? That's a biofilm, too. And so is the plaque that builds up on your teeth.
In the case of ears, though, biofilms might explain why it's so difficult to treat chronic ear infections—biofilms are not easily killed off by antibiotics. The image above, showing a biofilm-coated ear drum, was captured using a new imaging device that produces pictures from reflected light, the same way ultrasound makes images from reflected sound waves. It's part of a research paper that presents evidence about the role of biofilms in ear infection and long-term hearing loss.

Check out Scientific American for more information