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Updated: Jul 16, 2026
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Multiplex Detection of Bacteria in Complex Clinical and Environmental Samples using Oligonucleotide-coupled Fluorescent Microspheres
Published on: October 23, 2011
Does the bacterial DNA found in middle ear effusions come from viable bacteria?
Peizhong1, Whatmough, Birchall
1Departments of Physiology and ENT, University of Newcastle upon Tyne, Newcastle upon Tyne and Department of Otorhinolaryngology, University of Nottingham, Nottingham, UK).
Clinical Otolaryngology and Allied Sciences
|December 21, 2000
Summary
Middle ear effusions can protect bacterial DNA from breakdown, suggesting that positive polymerase chain reaction (PCR) results may indicate non-viable bacteria, not active infections.
Area of Science:
- Otolaryngology
- Microbiology
- Molecular Biology
Background:
- Otitis media with effusion (OME) frequently shows bacterial presence in middle ear fluid.
- Polymerase chain reaction (PCR) detects bacterial DNA in OME fluid, even when cultures are negative.
- This DNA detection is often attributed to bacterial biofilms, but fossilized DNA is an alternative explanation.
Purpose of the Study:
- To investigate whether middle ear effusions inhibit DNA breakdown by nucleases.
- To determine if this inhibition could explain the presence of bacterial DNA in OME fluid.
Main Methods:
- Middle ear effusion homogenates were incubated with DNA and DNase I.
- Viscosity assays measured DNA breakdown over time.
- DNase activity inhibition was quantified at different effusion concentrations.
Main Results:
- Middle ear effusions inhibited DNase activity in a concentration-dependent manner.
- Significant inhibition (48% and 91%) was observed with 1.5 ml and 3.0 ml of effusion, respectively.
- DNA breakdown was significantly reduced by the presence of effusion.
Conclusions:
- Middle ear effusions possess nuclease inhibitory properties.
- Bacterial DNA detected by PCR in OME may represent non-viable, fossilized remains rather than active bacterial infections.
- This finding has implications for interpreting molecular diagnostic results in OME.
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