• Hydrolytic enzymes have been shown to be present in middle ear effusions recovered from children with both persistent and acute otitis media. In the present study, we investigated the effect of ampicillin therapy on the expression of hydrolytic enzyme activity in acute middle ear effusions using the chinchilla animal model. The median values of enzyme activities were lower for the ampicillintreated animals when compared with the nontreated control animals. For the ampicillin-treated animals, eight of 12 assayed activities were characterized by a time-dependent decay of enzymatic activity. For the untreated animals, the majority of assayed activities (seven of 12) showed an increase in activity with time. These results show that sterilization of the middle ear cleft and elimination of the hydrolytic enzyme activity may be benefits of antimicrobial therapy and prerequisite to the healing of the inflamed mucosa. ( Arch Otolaryngol Head Neck Surg 1988;114:52-55)
