Source of bacterial RNA in chronic otitis media with effusion

The purpose of this study was to investigate whether the bacterial RNA detected by polymerase chain reaction (PCR) and reverse transcription (RT)-PCR methods in middle ear effusion (MEE) for pediatric chronic otitis media with effusion (OME) originated from live bacteria. Degradation of RNA was observed by spectroscopic analysis; we also investigated the effect of MEE on the digestive activity of RNase. The optical density of RNA solution was stable within 3 h. MEE could not degrade the RNA, while RNase could rapidly digest the RNA. MEE significantly inhibited the digestive activity of RNase, and the inhibitory effect was correlated with MEE concentration. The bacterial DNA and RNA detected by PCR and RT-PCR methods may not originate from live bacteria, but might instead originate from residues from previous bacterial infection(s). Chronic OME is not an infection of live bacteria, and therefore, antibiotics should be used with caution for clinical treatment of pediatric chronic OME.