Acute mastoiditis caused by Moraxella catarrhalis.

Acute mastoiditis is the most frequent intratemporal complication of otitis media. The bacteriology of acute otitis media is changing continuously and it differs markedly from the bacteriology of acute mastoiditis. Moraxella catarrhalis (M. catarrhalis) is the third most common bacteria found in acute otitis media, and in recent years its importance as an etiological factor of acute otitis media has markedly increased in certain geographic areas. However, there are no reports of acute mastoiditis caused solely by M. catarrhalis. This report describes a case of a 2-year-old girl with acute mastoiditis and M. catarrhalis in the bacterial culture of middle ear effusion.