The dynamics of bacteria in the middle ear during the course of acute otitis media with tympanostomy tube otorrhea.

BACKGROUND

Dynamics of bacteria during acute otitis media (AOM) has not been thoroughly studied because it requires repeated tympanocentesis. AOM with tympanostomy tube otorrhea provides a unique opportunity to study the appearance and disappearance of pathogens during the course of the disease without stressing the child.

METHODS

Middle ear fluid (MEF) samples were taken before treatment (amoxicillin clavulanate or placebo) and then daily during follow-up from 75 children having AOM with otorrhea through a tympanostomy tube. Bacteria were identified by culture, and typical AOM pathogens also by polymerase chain reaction.

RESULTS

Bacteria were initially shown in 67 (89%) children. New bacteria appeared in MEF more often in placebo than in amoxicillin clavulanate recipients [9 of 38 (24%) versus 2 of 37 (5%); P = 0.032]. During the follow-up, new occurrences of Moraxella catarrhalis were detected in MEF more frequently than those of Streptococcus pneumoniae or Haemophilus influenzae. Of the 28 patients with bilateral otorrhea, 11 (39%) had disparate bacteria at study entry and/or during the follow-up.

CONCLUSIONS

Changes in bacterial findings during the course of AOM are common in patients not receiving treatment, and even possible despite adequate treatment. In bilateral otorrhea, disparate bacterial findings are common.