Which bacteria or viruses cause ear infections ?

The ears have the same linings and are connected to the nose and throat through the eustacian tube. This means that any of the viruses that cause colds and sore throats can get through into your ears. Viruses are the main invaders, but bacteria can cause secondary infection. They seize the opportunity to invade after a virus has caused the initial problem - such as damaging the protective lining of the airway, or blocking up the eustacian tubes in your ears with mucus