If you have signs and symptoms of an ear infection, your doctor will use an otoscope to visualize the outer ear and eardrum. If an infection is present, the ear may appear red and swollen. There may also be a fluid discharge. Unlike other infections, the exact bacteria that is responsible cannot always be determined. As such, doctors choose antibiotics that will cover the most likely organisms when they suspect a bacterial source. This is because it can be difficult to obtain a sample from the ear for a culture. Antibiotics will not cure a viral infection, and it can take as long as three weeks for your body to fight off the virus.