Middle ear infections (acute otitis media). Bacteria can move from the nose, up the Eustachian tube and into the middle ear. As the bacteria multiply, the middle ear fills with pus, causing pain and irritability. Antibiotics should kill the bacteria and improve symptoms within a few days. Persisting middle ear infection (persistent acute otitis media). If the child is getting no improvement in his/her symptoms despite appropriate antibiotics, and the ear exam still shows signs of an infection, persistent acute otitis media is diagnosed. Recurring middle ear infections (recurrent acute otitis media). Some children's symptoms temporarily improve with antibiotics but then recur soon afterwards. Children having more than three symptomatic infections within a six-month period are classified as having recurrent acute otitis media. Middle ear fluid (otitis media with effusion). While antibiotics should kill the bacteria causing an infection within a few days, the middle ear fluid may take weeks to clear. During that time, the non-infected fluid is called otitis media with effusion. Some children, especially older children, develop middle ear fluid without ever having any actual infection.