Please help! what is the causative agent of otitis media?

Many possibilities: These can include a variety of respiratory viruses and bacteria that normally inhabit the throat. Pneumoccus, hemophillis influenza types, moxilla species, etc. These are often just opportunist germs that enter the space to take advantage of the fluid build up. A predisposing factor is the trapping of middle ear fluid behind a poorly draining eustachian tube.